[v6,1/3] dmaengine: Add support for APM X-Gene SoC DMA engine driver

Commit Message

Rameshwar Prasad Sahu Feb. 24, 2015, 12:53 p.m. UTC

This patch implements the APM X-Gene SoC DMA engine driver. The APM X-Gene
SoC DMA engine consists of 4 DMA channels for performing DMA operations.
These DMA operations include memory copy and scatter-gather memory copy
offloading.

Signed-off-by: Rameshwar Prasad Sahu <[e-mail]>
Signed-off-by: Loc Ho <[e-mail]>
---
 drivers/dma/Kconfig     |    8 +
 drivers/dma/Makefile    |    1 +
 drivers/dma/xgene-dma.c | 1738 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1747 insertions(+)
 create mode 100755 drivers/dma/xgene-dma.c

--
1.8.2.1

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Comments

Rameshwar Prasad Sahu Feb. 26, 2015, 12:31 p.m. UTC | #1

Hi Vinod,


On Tue, Feb 24, 2015 at 6:23 PM, Rameshwar Prasad Sahu <[e-mail]> wrote:
> This patch implements the APM X-Gene SoC DMA engine driver. The APM X-Gene
> SoC DMA engine consists of 4 DMA channels for performing DMA operations.
> These DMA operations include memory copy and scatter-gather memory copy
> offloading.
>
> Signed-off-by: Rameshwar Prasad Sahu <[e-mail]>
> Signed-off-by: Loc Ho <[e-mail]>
> ---
>  drivers/dma/Kconfig     |    8 +
>  drivers/dma/Makefile    |    1 +
>  drivers/dma/xgene-dma.c | 1738 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1747 insertions(+)
>  create mode 100755 drivers/dma/xgene-dma.c
>
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index a874b6e..0e05831 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -425,6 +425,14 @@ config IMG_MDC_DMA
>         help
>           Enable support for the IMG multi-threaded DMA controller (MDC).
>
> +config XGENE_DMA
> +       tristate "APM X-Gene DMA support"
> +       depends on ARCH_XGENE
> +       select DMA_ENGINE
> +       select ASYNC_TX_ENABLE_CHANNEL_SWITCH
> +       help
> +         Enable support for the APM X-Gene SoC DMA engine.
> +
>  config DMA_ENGINE
>         bool
>
> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
> index f915f61..06c1576 100644
> --- a/drivers/dma/Makefile
> +++ b/drivers/dma/Makefile
> @@ -51,3 +51,4 @@ obj-$(CONFIG_INTEL_MIC_X100_DMA) += mic_x100_dma.o
>  obj-$(CONFIG_NBPFAXI_DMA) += nbpfaxi.o
>  obj-$(CONFIG_DMA_SUN6I) += sun6i-dma.o
>  obj-$(CONFIG_IMG_MDC_DMA) += img-mdc-dma.o
> +obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
> diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
> new file mode 100755
> index 0000000..e736c2e
> --- /dev/null
> +++ b/drivers/dma/xgene-dma.c
> @@ -0,0 +1,1738 @@
> +/*
> + * Applied Micro X-Gene SoC DMA engine Driver
> + *
> + * Copyright (c) 2015, Applied Micro Circuits Corporation
> + * Authors: Rameshwar Prasad Sahu <[e-mail]>
> + *         Loc Ho <[e-mail]>
> + *
> + * This program is free software; you can redistribute  it and/or modify it
> + * under  the terms of  the GNU General  Public License as published by the
> + * Free Software Foundation;  either version 2 of the  License, or (at your
> + * option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + *
> + * NOTE: PM support is currently not available.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dmapool.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +
> +#include "dmaengine.h"
> +
> +/* DMA ring csr registers and bit definations */
> +#define DMA_RING_CONFIG                        0x04
> +#define DMA_RING_ENABLE                        BIT(31)
> +#define DMA_RING_ID                    0x08
> +#define DMA_RING_ID_SETUP(v)           ((v) | BIT(31))
> +#define DMA_RING_ID_BUF                        0x0C
> +#define DMA_RING_ID_BUF_SETUP(v)       (((v) << 9) | BIT(21))
> +#define DMA_RING_THRESLD0_SET1         0x30
> +#define DMA_RING_THRESLD0_SET1_VAL     0X64
> +#define DMA_RING_THRESLD1_SET1         0x34
> +#define DMA_RING_THRESLD1_SET1_VAL     0xC8
> +#define DMA_RING_HYSTERESIS            0x68
> +#define DMA_RING_HYSTERESIS_VAL                0xFFFFFFFF
> +#define DMA_RING_STATE                 0x6C
> +#define DMA_RING_STATE_WR_BASE         0x70
> +#define DMA_RING_NE_INT_MODE           0x017C
> +#define DMA_RING_NE_INT_MODE_SET(m, v) \
> +       ((m) = ((m) & ~BIT(31 - (v))) | BIT(31 - (v)))
> +#define DMA_RING_NE_INT_MODE_RESET(m, v)       \
> +       ((m) &= (~BIT(31 - (v))))
> +#define DMA_RING_CLKEN                 0xC208
> +#define DMA_RING_SRST                  0xC200
> +#define DMA_RING_MEM_RAM_SHUTDOWN      0xD070
> +#define DMA_RING_BLK_MEM_RDY           0xD074
> +#define DMA_RING_BLK_MEM_RDY_VAL       0xFFFFFFFF
> +#define DMA_RING_DESC_CNT(v)           (((v) & 0x0001FFFE) >> 1)
> +#define DMA_RING_ID_GET(owner, num)    (((owner) << 6) | (num))
> +#define DMA_RING_DST_ID(v)             ((1 << 10) | (v))
> +#define DMA_RING_CMD_OFFSET            0x2C
> +#define DMA_RING_CMD_BASE_OFFSET(v)    ((v) << 6)
> +#define DMA_RING_COHERENT_SET(m)       (((u32 *)(m))[2] |= BIT(4))
> +#define DMA_RING_ADDRL_SET(m, v)       (((u32 *)(m))[2] |= (((v) >> 8) << 5))
> +#define DMA_RING_ADDRH_SET(m, v)       (((u32 *)(m))[3] |= ((v) >> 35))
> +#define DMA_RING_ACCEPTLERR_SET(m)     (((u32 *)(m))[3] |= BIT(19))
> +#define DMA_RING_SIZE_SET(m, v)                (((u32 *)(m))[3] |= ((v) << 23))
> +#define DMA_RING_RECOMBBUF_SET(m)      (((u32 *)(m))[3] |= BIT(27))
> +#define DMA_RING_RECOMTIMEOUTL_SET(m)  (((u32 *)(m))[3] |= (0x7 << 28))
> +#define DMA_RING_RECOMTIMEOUTH_SET(m)  (((u32 *)(m))[4] |= 0x3)
> +#define DMA_RING_SELTHRSH_SET(m)       (((u32 *)(m))[4] |= BIT(3))
> +#define DMA_RING_TYPE_SET(m, v)                (((u32 *)(m))[4] |= ((v) << 19))
> +
> +/* DMA device csr registers and bit definitions */
> +#define DMA_IPBRR              0x0
> +#define DMA_DEV_ID_RD(v)       ((v) & 0x00000FFF)
> +#define DMA_BUS_ID_RD(v)       (((v) >> 12) & 3)
> +#define DMA_REV_NO_RD(v)       (((v) >> 14) & 3)
> +#define DMA_GCR                        0x10
> +#define DMA_CH_SETUP(v)                ((v) = ((v) & ~0x000FFFFF) | 0x000AAFFF)
> +#define DMA_ENABLE(v)          ((v) |= BIT(31))
> +#define DMA_DISABLE(v)         ((v) &= ~BIT(31))
> +#define DMA_INT                        0x70
> +#define DMA_INT_MASK           0x74
> +#define DMA_INT_ALL_MASK       0xFFFFFFFF
> +#define DMA_INT_ALL_UNMASK     0x0
> +#define DMA_INT_MASK_SHIFT     0x14
> +#define DMA_RING_INT0_MASK     0x90A0
> +#define DMA_RING_INT1_MASK     0x90A8
> +#define DMA_RING_INT2_MASK     0x90B0
> +#define DMA_RING_INT3_MASK     0x90B8
> +#define DMA_RING_INT4_MASK     0x90C0
> +#define DMA_CFG_RING_WQ_ASSOC  0x90E0
> +#define DMA_ASSOC_RING_MNGR1   0xFFFFFFFF
> +#define DMA_MEM_RAM_SHUTDOWN   0xD070
> +#define DMA_BLK_MEM_RDY                0xD074
> +#define DMA_BLK_MEM_RDY_VAL    0xFFFFFFFF
> +
> +/* DMA Descriptor format */
> +#define DMA_DESC_ELERR_RD(m)           (((m) >> 46) & 0x3)
> +#define DMA_DESC_NV_SET(m)             (((u64 *)(m))[0] |= BIT_ULL(50))
> +#define DMA_DESC_IN_SET(m)             (((u64 *)(m))[0] |= BIT_ULL(55))
> +#define DMA_DESC_RTYPE_SET(m, v)       (((u64 *)(m))[0] |= ((u64)(v) << 56))
> +#define DMA_DESC_LERR_RD(m)            (((m) >> 60) & 0x7)
> +#define DMA_DESC_BUFADDR_SET(m, v)     (((u64 *)(m))[0] |= (v))
> +#define DMA_DESC_BUFLEN_SET(m, v)      (((u64 *)(m))[0] |= ((u64)(v) << 48))
> +#define DMA_DESC_C_SET(m)              (((u64 *)(m))[1] |= BIT_ULL(63))
> +#define DMA_DESC_DR_SET(m)             (((u64 *)(m))[2] |= BIT_ULL(61))
> +#define DMA_DESC_DST_ADDR_SET(m, v)    (((u64 *)(m))[3] |= (v))
> +#define DMA_DESC_H0ENQ_NUM_SET(m, v)   (((u64 *)(m))[3] |= ((u64)(v) << 48))
> +#define DMA_DESC_STATUS(x, y)          (((x) << 4) | (y))
> +
> +/* DMA descriptor empty s/w signature */
> +#define DMA_DESC_EMPTY_INDEX           0
> +#define DMA_DESC_EMPTY_SIGNATURE       ~0ULL
> +#define DMA_DESC_SET_EMPTY(m)          \
> +       (((u64 *)(m))[DMA_DESC_EMPTY_INDEX] = DMA_DESC_EMPTY_SIGNATURE)
> +#define DMA_DESC_IS_EMPTY(m)           \
> +       (((u64 *)(m))[DMA_DESC_EMPTY_INDEX] == DMA_DESC_EMPTY_SIGNATURE)
> +
> +/* DMA configurable parameters defines */
> +#define DMA_RING_NUM                   512
> +#define DMA_BUFNUM                     0x0
> +#define DMA_CPU_BUFNUM                 0x18
> +#define DMA_RING_OWNER_DMA             0x03
> +#define DMA_RING_OWNER_CPU             0x0F
> +#define DMA_RING_TYPE_REGULAR          0x01
> +#define DMA_RING_WQ_DESC_SIZE          32
> +#define DMA_RING_NUM_CONFIG            5
> +#define DMA_MAX_CHANNEL                        4
> +#define DMA_MAX_BYTE_CNT               0x4000  /* 16 KB */
> +#define DMA_MAX_64B_DESC_BYTE_CNT      0x14000 /* 80 KB */
> +#define DMA_16K_BUFFER_LEN_CODE                0x0
> +#define DMA_INVALID_LEN_CODE           0x7800
> +
> +/* DMA descriptor error codes */
> +#define ERR_DESC_AXI           0x01
> +#define ERR_BAD_DESC           0x02
> +#define ERR_READ_DATA_AXI      0x03
> +#define ERR_WRITE_DATA_AXI     0x04
> +#define ERR_FBP_TIMEOUT                0x05
> +#define ERR_ECC                        0x06
> +#define ERR_DIFF_SIZE          0x08
> +#define ERR_SCT_GAT_LEN                0x09
> +#define ERR_CRC_ERR            0x11
> +#define ERR_CHKSUM             0x12
> +#define ERR_DIF                        0x13
> +
> +/* DMA error interrupt codes */
> +#define ERR_DIF_SIZE_INT       0x0
> +#define ERR_GS_ERR_INT         0x1
> +#define ERR_FPB_TIMEO_INT      0x2
> +#define ERR_WFIFO_OVF_INT      0x3
> +#define ERR_RFIFO_OVF_INT      0x4
> +#define ERR_WR_TIMEO_INT       0x5
> +#define ERR_RD_TIMEO_INT       0x6
> +#define ERR_WR_ERR_INT         0x7
> +#define ERR_RD_ERR_INT         0x8
> +#define ERR_BAD_DESC_INT       0x9
> +#define ERR_DESC_DST_INT       0xA
> +#define ERR_DESC_SRC_INT       0xB
> +
> +/* Define to dump DMA descriptor */
> +#define DMA_DESC_ERR_DUMP(desc)        \
> +       print_hex_dump(KERN_ERR, "X-Gene DMA: Rx ERR DESC ",    \
> +                       DUMP_PREFIX_ADDRESS, 16, 8, (desc), 32, 0)
> +
> +#define to_dma_desc_sw(tx)     \
> +       container_of(tx, struct xgene_dma_desc_sw, tx)
> +#define to_dma_chan(dchan)     \
> +       container_of(dchan, struct xgene_dma_chan, dma_chan)
> +
> +#define chan_dbg(chan, fmt, arg...)    \
> +       dev_dbg(chan->dev, "%s: " fmt, chan->name, ##arg)
> +#define chan_err(chan, fmt, arg...)    \
> +       dev_err(chan->dev, "%s: " fmt, chan->name, ##arg)
> +
> +struct xgene_dma_desc_hw {
> +       u64 m0;
> +       u64 m1;
> +       u64 m2;
> +       u64 m3;
> +};
> +
> +enum xgene_dma_ring_cfgsize {
> +       DMA_RING_CFG_SIZE_512B,
> +       DMA_RING_CFG_SIZE_2KB,
> +       DMA_RING_CFG_SIZE_16KB,
> +       DMA_RING_CFG_SIZE_64KB,
> +       DMA_RING_CFG_SIZE_512KB,
> +       DMA_RING_CFG_SIZE_INVALID
> +};
> +
> +struct xgene_dma_ring {
> +       struct xgene_dma *pdma;
> +       u8 buf_num;
> +       u16 id;
> +       u16 num;
> +       u16 head;
> +       u16 owner;
> +       u16 slots;
> +       u16 dst_ring_num;
> +       u32 size;
> +       void __iomem *cmd;
> +       void __iomem *cmd_base;
> +       dma_addr_t desc_paddr;
> +       u32 state[DMA_RING_NUM_CONFIG];
> +       enum xgene_dma_ring_cfgsize cfgsize;
> +       union {
> +               void *desc_vaddr;
> +               struct xgene_dma_desc_hw *desc_hw;
> +       };
> +};
> +
> +struct xgene_dma_desc_sw {
> +       struct xgene_dma_desc_hw desc1;
> +       struct xgene_dma_desc_hw desc2;
> +       u8 desc_cnt;
> +       struct list_head node;
> +       struct list_head tx_list;
> +       struct dma_async_tx_descriptor tx;
> +};
> +
> +/**
> + * struct xgene_dma_chan - internal representation of an DMA channel
> + * @dma_chan: dmaengine channel object member
> + * @pdma: DMA device structure reference
> + * @dev: struct device reference for dma mapping api
> + * @id: raw id of this channel
> + * @rx_irq: channel IRQ
> + * @name: name of DMA channel
> + * @lock: serializes enqueue/dequeue operations to the descriptor pool
> + * @pending: number of transaction request pushed to DMA controller for
> + *     execution, but still waiting for completion,
> + * @ld_pending: descriptors which are queued to run, but have not yet been
> + *     submitted to the hardware for execution
> + * @ld_running: descriptors which are currently being executing by the hardware
> + * @ld_completed: descriptors which have finished execution by the hardware.
> + *     These descriptors have already had their cleanup actions run. They
> + *     are waiting for the ACK bit to be set by the async tx API.
> + * @desc_pool: descriptor pool for DMA operations
> + * @tasklet: bottom half where all completed descriptors cleans
> + * @tx_ring: transmit ring descriptor that we use to prepare actual
> + *     descriptors for further executions
> + * @rx_ring: receive ring descriptor that we use to get completed DMA
> + *     descriptors during cleanup time
> + */
> +struct xgene_dma_chan {
> +       struct dma_chan dma_chan;
> +       struct xgene_dma *pdma;
> +       struct device *dev;
> +       int id;
> +       int rx_irq;
> +       char name[8];
> +       spinlock_t lock;
> +       int pending;
> +       struct list_head ld_pending;
> +       struct list_head ld_running;
> +       struct list_head ld_completed;
> +       struct dma_pool *desc_pool;
> +       struct tasklet_struct tasklet;
> +       struct xgene_dma_ring tx_ring;
> +       struct xgene_dma_ring rx_ring;
> +};
> +
> +/**
> + * struct xgene_dma - internal representation of an DMA device
> + * @err_irq: DMA error irq number
> + * @ring_num: start id number for DMA ring
> + * @csr_dma: base for DMA register access
> + * @csr_ring: base for DMA ring register access
> + * @csr_ring_cmd: base for DMA ring command register access
> + * @dma_dev: embedded struct dma_device
> + * @chan: reference to DMA channels
> + */
> +struct xgene_dma {
> +       struct device *dev;
> +       struct clk *clk;
> +       int err_irq;
> +       int ring_num;
> +       void __iomem *csr_dma;
> +       void __iomem *csr_ring;
> +       void __iomem *csr_ring_cmd;
> +       struct dma_device dma_dev[DMA_MAX_CHANNEL];
> +       struct xgene_dma_chan chan[DMA_MAX_CHANNEL];
> +};
> +
> +static const char * const xgene_dma_desc_hw_err[] = {
> +       [ERR_DESC_AXI] = "AXI error when reading src/dst link list",
> +       [ERR_BAD_DESC] = "ERR or El_ERR fields not set to zero in desc",
> +       [ERR_READ_DATA_AXI] = "AXI error when reading data",
> +       [ERR_WRITE_DATA_AXI] = "AXI error when writing data",
> +       [ERR_FBP_TIMEOUT] = "Timeout on bufpool fetch",
> +       [ERR_ECC] = "ECC double bit error",
> +       [ERR_DIFF_SIZE] = "Bufpool too small to hold all the DIF result",
> +       [ERR_SCT_GAT_LEN] = "Gather and scatter data length not same",
> +       [ERR_CRC_ERR] = "CRC error",
> +       [ERR_CHKSUM] = "Checksum error",
> +       [ERR_DIF] = "DIF error",
> +};
> +
> +static const char * const xgene_dma_err[] = {
> +       [ERR_DIF_SIZE_INT] = "DIF size error",
> +       [ERR_GS_ERR_INT] = "Gather scatter not same size error",
> +       [ERR_FPB_TIMEO_INT] = "Free pool time out error",
> +       [ERR_WFIFO_OVF_INT] = "Write FIFO over flow error",
> +       [ERR_RFIFO_OVF_INT] = "Read FIFO over flow error",
> +       [ERR_WR_TIMEO_INT] = "Write time out error",
> +       [ERR_RD_TIMEO_INT] = "Read time out error",
> +       [ERR_WR_ERR_INT] = "HBF bus write error",
> +       [ERR_RD_ERR_INT] = "HBF bus read error",
> +       [ERR_BAD_DESC_INT] = "Ring descriptor HE0 not set error",
> +       [ERR_DESC_DST_INT] = "HFB reading dst link address error",
> +       [ERR_DESC_SRC_INT] = "HFB reading src link address error",
> +};
> +
> +static void xgene_dma_cpu_to_le64(u64 *desc, int count)
> +{
> +       int i;
> +
> +       for (i = 0; i < count; i++)
> +               desc[i] = cpu_to_le64(desc[i]);
> +}
> +
> +static u16 xgene_dma_encode_len(u32 len)
> +{
> +       return (len < DMA_MAX_BYTE_CNT) ?
> +               len : DMA_16K_BUFFER_LEN_CODE;
> +}
> +
> +static u32 xgene_dma_ring_desc_cnt(struct xgene_dma_ring *ring)
> +{
> +       u32 __iomem *cmd_base = ring->cmd_base;
> +       u32 ring_state = ioread32(&cmd_base[1]);
> +
> +       return DMA_RING_DESC_CNT(ring_state);
> +}
> +
> +static void xgene_dma_set_src_buffer(void *ext8, size_t *len,
> +                                    dma_addr_t *paddr)
> +{
> +       size_t nbytes = (*len < DMA_MAX_BYTE_CNT) ?
> +                       *len : DMA_MAX_BYTE_CNT;
> +
> +       DMA_DESC_BUFADDR_SET(ext8, *paddr);
> +       DMA_DESC_BUFLEN_SET(ext8, xgene_dma_encode_len(*len));
> +       *len -= nbytes;
> +       *paddr += nbytes;
> +}
> +
> +static void xgene_dma_invalidate_buffer(void *ext8)
> +{
> +       DMA_DESC_BUFLEN_SET(ext8, DMA_INVALID_LEN_CODE);
> +}
> +
> +static void *xgene_dma_lookup_ext8(u64 *desc, int idx)
> +{
> +       return (idx % 2) ? (desc + idx - 1) : (desc + idx + 1);
> +}
> +
> +static void xgene_dma_init_desc(void *desc, u16 dst_ring_num)
> +{
> +       DMA_DESC_C_SET(desc); /* Coherent IO */
> +       DMA_DESC_IN_SET(desc);
> +       DMA_DESC_DR_SET(desc);
> +       DMA_DESC_RTYPE_SET(desc, DMA_RING_OWNER_DMA);
> +       DMA_DESC_H0ENQ_NUM_SET(desc, dst_ring_num);
> +}
> +
> +static void xgene_dma_prep_cpy_desc(struct xgene_dma_chan *chan,
> +                                   struct xgene_dma_desc_sw *desc_sw,
> +                                   dma_addr_t dst, dma_addr_t src,
> +                                   size_t len)
> +{
> +       struct xgene_dma_ring *ring = &chan->tx_ring;
> +       void *desc1, *desc2;
> +       int i;
> +
> +       /* Get 1st descriptor */
> +       desc1 = &desc_sw->desc1;
> +       xgene_dma_init_desc(desc1, ring->dst_ring_num);
> +       DMA_DESC_DST_ADDR_SET(desc1, dst);
> +
> +       /* Set 1st source address */
> +       xgene_dma_set_src_buffer(desc1 + 8, &len, &src);
> +
> +       if (len <= 0) {
> +               desc2 = NULL;
> +               desc_sw->desc_cnt = 1;
> +               goto skip_additional_src;
> +       }
> +
> +       /*
> +        * We need to split this source buffer,
> +        * and need to use 2nd descriptor
> +        */
> +       desc2 = &desc_sw->desc2;
> +       DMA_DESC_NV_SET(desc1);
> +
> +       /* Set 2nd to 5th source address */
> +       for (i = 0; i < 4 && len; i++)
> +               xgene_dma_set_src_buffer(xgene_dma_lookup_ext8(desc2, i),
> +                                        &len, &src);
> +
> +       /* Invalidate unused source address field */
> +       for (; i < 4; i++)
> +               xgene_dma_invalidate_buffer(xgene_dma_lookup_ext8(desc2, i));
> +
> +       desc_sw->desc_cnt = 2;
> +
> +skip_additional_src:
> +       /* Hardware stores descriptor in little endian format */
> +       xgene_dma_cpu_to_le64(desc1, 4);
> +       if (desc2)
> +               xgene_dma_cpu_to_le64(desc2, 4);
> +}
> +
> +static dma_cookie_t xgene_dma_tx_submit(struct dma_async_tx_descriptor *tx)
> +{
> +       struct xgene_dma_desc_sw *desc;
> +       struct xgene_dma_chan *chan;
> +       dma_cookie_t cookie;
> +
> +       if (unlikely(!tx))
> +               return -EINVAL;
> +
> +       chan = to_dma_chan(tx->chan);
> +       desc = to_dma_desc_sw(tx);
> +
> +       spin_lock_bh(&chan->lock);
> +
> +       cookie = dma_cookie_assign(tx);
> +
> +       /* Add this transaction list onto the tail of the pending queue */
> +       list_splice_tail_init(&desc->tx_list, &chan->ld_pending);
> +
> +       spin_unlock_bh(&chan->lock);
> +
> +       return cookie;
> +}
> +
> +static void xgene_dma_free_descriptor(struct xgene_dma_chan *chan,
> +                                     struct xgene_dma_desc_sw *desc)
> +{
> +       list_del(&desc->node);
> +       chan_dbg(chan, "LD %p free\n", desc);
> +       dma_pool_free(chan->desc_pool, desc, desc->tx.phys);
> +}
> +
> +static struct xgene_dma_desc_sw *xgene_dma_alloc_descriptor(
> +                                struct xgene_dma_chan *chan)
> +{
> +       struct xgene_dma_desc_sw *desc;
> +       dma_addr_t phys;
> +
> +       desc = dma_pool_alloc(chan->desc_pool, GFP_NOWAIT, &phys);
> +       if (!desc) {
> +               chan_dbg(chan, "Failed to allocate LDs\n");
> +               return NULL;
> +       }
> +
> +       memset(desc, 0, sizeof(*desc));
> +
> +       INIT_LIST_HEAD(&desc->tx_list);
> +       desc->tx.phys = phys;
> +       desc->tx.tx_submit = xgene_dma_tx_submit;
> +       dma_async_tx_descriptor_init(&desc->tx, &chan->dma_chan);
> +
> +       chan_dbg(chan, "LD %p allocated\n", desc);
> +
> +       return desc;
> +}
> +
> +/**
> + * xgene_dma_clean_completed_descriptor - free all descriptors which
> + * has been completed and acked
> + * @chan: DMA channel
> + *
> + * This function is used on all completed and acked descriptors.
> + * All descriptors should only be freed in this function.
> + */
> +static void xgene_dma_clean_completed_descriptor(struct xgene_dma_chan *chan)
> +{
> +       struct xgene_dma_desc_sw *desc, *_desc;
> +
> +       /* Run the callback for each descriptor, in order */
> +       list_for_each_entry_safe(desc, _desc, &chan->ld_completed, node) {
> +               if (async_tx_test_ack(&desc->tx))
> +                       xgene_dma_free_descriptor(chan, desc);
> +       }
> +}
> +
> +/**
> + * xgene_dma_run_tx_complete_actions - cleanup a single link descriptor
> + * @chan: DMA channel
> + * @desc: descriptor to cleanup and free
> + *
> + * This function is used on a descriptor which has been executed by the DMA
> + * controller. It will run any callbacks, submit any dependencies.
> + */
> +static void xgene_dma_run_tx_complete_actions(struct xgene_dma_chan *chan,
> +                                             struct xgene_dma_desc_sw *desc)
> +{
> +       struct dma_async_tx_descriptor *tx = &desc->tx;
> +
> +       if (tx->cookie == 0)
> +               return;
> +
> +       dma_cookie_complete(tx);
> +
> +       /* Run the link descriptor callback function */
> +       if (tx->callback)
> +               tx->callback(tx->callback_param);
> +
> +       dma_descriptor_unmap(tx);
> +
> +       /* Run any dependencies */
> +       dma_run_dependencies(tx);
> +}
> +
> +/**
> + * xgene_dma_clean_running_descriptor - move the completed descriptor from
> + * ld_running to ld_completed
> + * @chan: DMA channel
> + * @desc: the descriptor which is completed
> + *
> + * Free the descriptor directly if acked by async_tx api, or move it to
> + * queue ld_completed.
> + */
> +static void xgene_dma_clean_running_descriptor(struct xgene_dma_chan *chan,
> +                                              struct xgene_dma_desc_sw *desc)
> +{
> +       /* Remove from the list of transactions */
> +       list_del(&desc->node);
> +
> +       /*
> +        * the client is allowed to attach dependent operations
> +        * until 'ack' is set
> +        */
> +       if (!async_tx_test_ack(&desc->tx)) {
> +               /*
> +                * Move this descriptor to the list of descriptors which is
> +                * completed, but still awaiting the 'ack' bit to be set.
> +                */
> +               list_add_tail(&desc->node, &chan->ld_completed);
> +               return;
> +       }
> +
> +       chan_dbg(chan, "LD %p free\n", desc);
> +       dma_pool_free(chan->desc_pool, desc, desc->tx.phys);
> +}
> +
> +/**
> + * xgene_chan_xfer_ld_pending - push any pending transactions to hw
> + * @chan : DMA channel
> + *
> + * LOCKING: must hold chan->desc_lock
> + */
> +static void xgene_chan_xfer_ld_pending(struct xgene_dma_chan *chan)
> +{
> +       struct xgene_dma_ring *ring = &chan->tx_ring;
> +       struct xgene_dma_desc_sw *desc_sw, *_desc_sw;
> +       struct xgene_dma_desc_hw *desc_hw;
> +
> +       /*
> +        * If the list of pending descriptors is empty, then we
> +        * don't need to do any work at all
> +        */
> +       if (list_empty(&chan->ld_pending)) {
> +               chan_dbg(chan, "No pending LDs\n");
> +               return;
> +       }
> +
> +       /*
> +        * Move elements from the queue of pending transactions onto the list
> +        * of running transactions and push it to hw for further executions
> +        */
> +
> +       list_for_each_entry_safe(desc_sw, _desc_sw, &chan->ld_pending, node) {
> +               /*
> +                * Check if have pushed max number of transactions to hw
> +                * as capable, so let's stop here and will push remaining
> +                * elements from pening ld queue after completing some
> +                * descriptors that we have already pushed
> +                */
> +               if ((chan->pending >= ring->slots) ||
> +                   (xgene_dma_ring_desc_cnt(ring) > (ring->slots - 2)))
> +                       break;
> +
> +               /* Get hw descriptor from DMA tx ring */
> +               desc_hw = &ring->desc_hw[ring->head];
> +
> +               /*
> +                * Increment the head count to point next
> +                * descriptor for next time
> +                */
> +               if (++ring->head == ring->slots)
> +                       ring->head = 0;
> +
> +               /* Copy prepared sw descriptor data to hw descriptor */
> +               memcpy(desc_hw, &desc_sw->desc1, sizeof(*desc_hw));
> +
> +               /*
> +                * Check if we have prepared 64B descriptor,
> +                * in this case we need one more hw descriptor
> +                */
> +               if (desc_sw->desc_cnt == 2) {
> +                       desc_hw = &ring->desc_hw[ring->head];
> +
> +                       if (++ring->head == ring->slots)
> +                               ring->head = 0;
> +
> +                       memcpy(desc_hw, &desc_sw->desc2, sizeof(*desc_hw));
> +               }
> +
> +               /*
> +                * Delete this element from ld pending queue and append it to
> +                * ld running queue
> +                */
> +               list_move_tail(&desc_sw->node, &chan->ld_running);
> +
> +               /* Increment the pending transaction count */
> +               chan->pending++;
> +
> +               /* Notify the hw that we have descriptor ready for execution */
> +               iowrite32(desc_sw->desc_cnt, ring->cmd);
> +       }
> +}
> +
> +/**
> + * xgene_dma_cleanup_descriptors - cleanup link descriptors which are completed
> + * and move them to ld_completed to free until flag 'ack' is set
> + * @chan: DMA channel
> + *
> + * This function is used on descriptors which have been executed by the DMA
> + * controller. It will run any callbacks, submit any dependencies, then
> + * free these descriptors if flag 'ack' is set.
> + */
> +static void xgene_dma_cleanup_descriptors(struct xgene_dma_chan *chan)
> +{
> +       struct xgene_dma_ring *ring = &chan->rx_ring;
> +       struct xgene_dma_desc_sw *desc_sw, *_desc_sw;
> +       struct xgene_dma_desc_hw *desc_hw;
> +       u8 status;
> +
> +       /* Clean already completed and acked descriptors */
> +       xgene_dma_clean_completed_descriptor(chan);
> +
> +       /* Run the callback for each descriptor, in order */
> +       list_for_each_entry_safe(desc_sw, _desc_sw, &chan->ld_running, node) {
> +               /* Get subsequent hw descriptor from DMA rx ring */
> +               desc_hw = &ring->desc_hw[ring->head];
> +
> +               /* Check if this descriptor has been completed */
> +               if (unlikely(DMA_DESC_IS_EMPTY(desc_hw)))
> +                       break;
> +
> +               if (++ring->head == ring->slots)
> +                       ring->head = 0;
> +
> +               /* Check if we have any error with DMA transactions */
> +               status = DMA_DESC_STATUS(
> +                               DMA_DESC_ELERR_RD(le64_to_cpu(desc_hw->m0)),
> +                               DMA_DESC_LERR_RD(le64_to_cpu(desc_hw->m0)));
> +               if (status) {
> +                       chan_err(chan, "%s\n", xgene_dma_desc_hw_err[status]);
> +                       DMA_DESC_ERR_DUMP(desc_hw);
> +               }
> +
> +               /* Notify the hw about this completed descriptor */
> +               iowrite32(-1, ring->cmd);
> +
> +               /* Mark this hw descriptor as processed */
> +               DMA_DESC_SET_EMPTY(desc_hw);
> +
> +               xgene_dma_run_tx_complete_actions(chan, desc_sw);
> +
> +               xgene_dma_clean_running_descriptor(chan, desc_sw);
> +
> +               /*
> +                * Decrement the pending transaction count
> +                * as we have processed one
> +                */
> +               chan->pending--;
> +       }
> +
> +       /*
> +        * Start any pending transactions automatically
> +        *
> +        * In the ideal case, we keep the DMA controller busy while we go
> +        * ahead and free the descriptors below.
> +        */
> +       xgene_chan_xfer_ld_pending(chan);
> +}
> +
> +static int xgene_dma_alloc_chan_resources(struct dma_chan *dchan)
> +{
> +       struct xgene_dma_chan *chan = to_dma_chan(dchan);
> +
> +       /* Has this channel already been allocated? */
> +       if (chan->desc_pool)
> +               return 1;
> +
> +       chan->desc_pool = dma_pool_create(chan->name, chan->dev,
> +                                         sizeof(struct xgene_dma_desc_sw),
> +                                         0, 0);
> +       if (!chan->desc_pool) {
> +               chan_err(chan, "Failed to allocate descriptor pool\n");
> +               return -ENOMEM;
> +       }
> +
> +       chan_dbg(chan, "Allocate descripto pool\n");
> +
> +       return 1;
> +}
> +
> +/**
> + * xgene_dma_free_desc_list - Free all descriptors in a queue
> + * @chan: DMA channel
> + * @list: the list to free
> + *
> + * LOCKING: must hold chan->desc_lock
> + */
> +static void xgene_dma_free_desc_list(struct xgene_dma_chan *chan,
> +                                    struct list_head *list)
> +{
> +       struct xgene_dma_desc_sw *desc, *_desc;
> +
> +       list_for_each_entry_safe(desc, _desc, list, node)
> +               xgene_dma_free_descriptor(chan, desc);
> +}
> +
> +static void xgene_dma_free_desc_list_reverse(struct xgene_dma_chan *chan,
> +                                            struct list_head *list)
> +{
> +       struct xgene_dma_desc_sw *desc, *_desc;
> +
> +       list_for_each_entry_safe_reverse(desc, _desc, list, node)
> +               xgene_dma_free_descriptor(chan, desc);
> +}
> +
> +static void xgene_dma_free_chan_resources(struct dma_chan *dchan)
> +{
> +       struct xgene_dma_chan *chan = to_dma_chan(dchan);
> +
> +       chan_dbg(chan, "Free all resources\n");
> +
> +       if (!chan->desc_pool)
> +               return;
> +
> +       spin_lock_bh(&chan->lock);
> +
> +       /* Process all running descriptor */
> +       xgene_dma_cleanup_descriptors(chan);
> +
> +       /* Clean all link descriptor queues */
> +       xgene_dma_free_desc_list(chan, &chan->ld_pending);
> +       xgene_dma_free_desc_list(chan, &chan->ld_running);
> +       xgene_dma_free_desc_list(chan, &chan->ld_completed);
> +
> +       /* Delete this channel DMA pool */
> +       dma_pool_destroy(chan->desc_pool);
> +       chan->desc_pool = NULL;
> +
> +       spin_unlock_bh(&chan->lock);
> +}
> +
> +static struct dma_async_tx_descriptor *xgene_dma_prep_memcpy(
> +       struct dma_chan *dchan, dma_addr_t dst, dma_addr_t src,
> +       size_t len, unsigned long flags)
> +{
> +       struct xgene_dma_desc_sw *first = NULL, *new;
> +       struct xgene_dma_chan *chan;
> +       size_t copy;
> +
> +       if (unlikely(!dchan || (len == 0)))
> +               return NULL;
> +
> +       chan = to_dma_chan(dchan);
> +
> +       do {
> +               /* Allocate the link descriptor from DMA pool */
> +               new = xgene_dma_alloc_descriptor(chan);
> +               if (!new)
> +                       goto fail;
> +
> +               /* Create the largest transaction possible */
> +               copy = min_t(size_t, len, DMA_MAX_64B_DESC_BYTE_CNT);
> +
> +               /* Prepare DMA descriptor */
> +               xgene_dma_prep_cpy_desc(chan, new, dst, src, copy);
> +
> +               if (!first)
> +                       first = new;
> +
> +               new->tx.cookie = 0;
> +               async_tx_ack(&new->tx);
> +
> +               /* Update metadata */
> +               len -= copy;
> +               dst += copy;
> +               src += copy;
> +
> +               /* Insert the link descriptor to the LD ring */
> +               list_add_tail(&new->node, &first->tx_list);
> +       } while (len);
> +
> +       new->tx.flags = flags; /* client is in control of this ack */
> +       new->tx.cookie = -EBUSY;
> +       list_splice(&first->tx_list, &new->tx_list);
> +
> +       return &new->tx;
> +
> +fail:
> +       if (!first)
> +               return NULL;
> +
> +       xgene_dma_free_desc_list_reverse(chan, &first->tx_list);
> +       return NULL;
> +}
> +
> +static struct dma_async_tx_descriptor *xgene_dma_prep_sg(
> +       struct dma_chan *dchan, struct scatterlist *dst_sg,
> +       unsigned int dst_nents, struct scatterlist *src_sg,
> +       unsigned int src_nents, unsigned long flags)
> +{
> +       struct xgene_dma_desc_sw *first = NULL, *new = NULL;
> +       struct xgene_dma_chan *chan;
> +       size_t dst_avail, src_avail;
> +       dma_addr_t dst, src;
> +       size_t len;
> +
> +       if (unlikely(!dchan))
> +               return NULL;
> +
> +       if (unlikely(dst_nents == 0 || src_nents == 0))
> +               return NULL;
> +
> +       if (unlikely(!dst_sg || !src_sg))
> +               return NULL;
> +
> +       chan = to_dma_chan(dchan);
> +
> +       /* Get prepared for the loop */
> +       dst_avail = sg_dma_len(dst_sg);
> +       src_avail = sg_dma_len(src_sg);
> +       dst_nents--;
> +       src_nents--;
> +
> +       /* Run until we are out of scatterlist entries */
> +       while (true) {
> +               /* Create the largest transaction possible */
> +               len = min_t(size_t, src_avail, dst_avail);
> +               len = min_t(size_t, len, DMA_MAX_64B_DESC_BYTE_CNT);
> +               if (len == 0)
> +                       goto fetch;
> +
> +               dst = sg_dma_address(dst_sg) + sg_dma_len(dst_sg) - dst_avail;
> +               src = sg_dma_address(src_sg) + sg_dma_len(src_sg) - src_avail;
> +
> +               /* Allocate the link descriptor from DMA pool */
> +               new = xgene_dma_alloc_descriptor(chan);
> +               if (!new)
> +                       goto fail;
> +
> +               /* Prepare DMA descriptor */
> +               xgene_dma_prep_cpy_desc(chan, new, dst, src, len);
> +
> +               if (!first)
> +                       first = new;
> +
> +               new->tx.cookie = 0;
> +               async_tx_ack(&new->tx);
> +
> +               /* update metadata */
> +               dst_avail -= len;
> +               src_avail -= len;
> +
> +               /* Insert the link descriptor to the LD ring */
> +               list_add_tail(&new->node, &first->tx_list);
> +
> +fetch:
> +               /* fetch the next dst scatterlist entry */
> +               if (dst_avail == 0) {
> +                       /* no more entries: we're done */
> +                       if (dst_nents == 0)
> +                               break;
> +
> +                       /* fetch the next entry: if there are no more: done */
> +                       dst_sg = sg_next(dst_sg);
> +                       if (!dst_sg)
> +                               break;
> +
> +                       dst_nents--;
> +                       dst_avail = sg_dma_len(dst_sg);
> +               }
> +
> +               /* fetch the next src scatterlist entry */
> +               if (src_avail == 0) {
> +                       /* no more entries: we're done */
> +                       if (src_nents == 0)
> +                               break;
> +
> +                       /* fetch the next entry: if there are no more: done */
> +                       src_sg = sg_next(src_sg);
> +                       if (!src_sg)
> +                               break;
> +
> +                       src_nents--;
> +                       src_avail = sg_dma_len(src_sg);
> +               }
> +       }
> +
> +       if (!new)
> +               return NULL;
> +
> +       new->tx.flags = flags; /* client is in control of this ack */
> +       new->tx.cookie = -EBUSY;
> +       list_splice(&first->tx_list, &new->tx_list);
> +
> +       return &new->tx;
> +
> +fail:
> +       if (!first)
> +               return NULL;
> +
> +       xgene_dma_free_desc_list_reverse(chan, &first->tx_list);
> +       return NULL;
> +}
> +
> +static void xgene_dma_issue_pending(struct dma_chan *dchan)
> +{
> +       struct xgene_dma_chan *chan = to_dma_chan(dchan);
> +
> +       spin_lock_bh(&chan->lock);
> +       xgene_chan_xfer_ld_pending(chan);
> +       spin_unlock_bh(&chan->lock);
> +}
> +
> +static enum dma_status xgene_dma_tx_status(struct dma_chan *dchan,
> +                                          dma_cookie_t cookie,
> +                                          struct dma_tx_state *txstate)
> +{
> +       struct xgene_dma_chan *chan = to_dma_chan(dchan);
> +       enum dma_status status;
> +
> +       status = dma_cookie_status(dchan, cookie, txstate);
> +       if (status == DMA_COMPLETE)
> +               return status;
> +
> +       /* Cleanup any running and executed descriptors */
> +       spin_lock_bh(&chan->lock);
> +       xgene_dma_cleanup_descriptors(chan);
> +       spin_unlock_bh(&chan->lock);
> +
> +       return dma_cookie_status(dchan, cookie, txstate);
> +}
> +
> +static void xgene_dma_tasklet_cb(unsigned long data)
> +{
> +       struct xgene_dma_chan *chan = (struct xgene_dma_chan *)data;
> +
> +       spin_lock_bh(&chan->lock);
> +
> +       /* Run all cleanup for descriptors which have been completed */
> +       xgene_dma_cleanup_descriptors(chan);
> +
> +       /* Re-enable DMA channel IRQ */
> +       enable_irq(chan->rx_irq);
> +
> +       spin_unlock_bh(&chan->lock);
> +}
> +
> +static irqreturn_t xgene_dma_chan_ring_isr(int irq, void *id)
> +{
> +       struct xgene_dma_chan *chan = (struct xgene_dma_chan *)id;
> +
> +       BUG_ON(!chan);
> +
> +       /*
> +        * Disable DMA channel IRQ until we process completed
> +        * descriptors
> +        */
> +       disable_irq_nosync(chan->rx_irq);
> +
> +       /*
> +        * Schedule the tasklet to handle all cleanup of the current
> +        * transaction. It will start a new transaction if there is
> +        * one pending.
> +        */
> +       tasklet_schedule(&chan->tasklet);
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t xgene_dma_err_isr(int irq, void *id)
> +{
> +       struct xgene_dma *pdma = (struct xgene_dma *)id;
> +       unsigned long int_mask;
> +       u32 val, i;
> +
> +       val = ioread32(pdma->csr_dma + DMA_INT);
> +
> +       /* Clear DMA interrupts */
> +       iowrite32(val, pdma->csr_dma + DMA_INT);
> +
> +       /* Print DMA error info */
> +       int_mask = val >> DMA_INT_MASK_SHIFT;
> +       for_each_set_bit(i, &int_mask, ARRAY_SIZE(xgene_dma_err))
> +               dev_err(pdma->dev,
> +                       "Interrupt status 0x%08X %s\n", val, xgene_dma_err[i]);
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static void xgene_dma_wr_ring_state(struct xgene_dma_ring *ring)
> +{
> +       int i;
> +
> +       iowrite32(ring->num, ring->pdma->csr_ring + DMA_RING_STATE);
> +
> +       for (i = 0; i < DMA_RING_NUM_CONFIG; i++)
> +               iowrite32(ring->state[i], ring->pdma->csr_ring +
> +                         DMA_RING_STATE_WR_BASE + (i * 4));
> +}
> +
> +static void xgene_dma_clr_ring_state(struct xgene_dma_ring *ring)
> +{
> +       memset(ring->state, 0, sizeof(u32) * DMA_RING_NUM_CONFIG);
> +       xgene_dma_wr_ring_state(ring);
> +}
> +
> +static void xgene_dma_setup_ring(struct xgene_dma_ring *ring)
> +{
> +       void *ring_cfg = ring->state;
> +       u64 addr = ring->desc_paddr;
> +       void *desc;
> +       u32 i, val;
> +
> +       ring->slots = ring->size / DMA_RING_WQ_DESC_SIZE;
> +
> +       /* Clear DMA ring state */
> +       xgene_dma_clr_ring_state(ring);
> +
> +       /* Set DMA ring type */
> +       DMA_RING_TYPE_SET(ring_cfg, DMA_RING_TYPE_REGULAR);
> +
> +       if (ring->owner == DMA_RING_OWNER_DMA) {
> +               /* Set recombination buffer and timeout */
> +               DMA_RING_RECOMBBUF_SET(ring_cfg);
> +               DMA_RING_RECOMTIMEOUTL_SET(ring_cfg);
> +               DMA_RING_RECOMTIMEOUTH_SET(ring_cfg);
> +       }
> +
> +       /* Initialize DMA ring state */
> +       DMA_RING_SELTHRSH_SET(ring_cfg);
> +       DMA_RING_ACCEPTLERR_SET(ring_cfg);
> +       DMA_RING_COHERENT_SET(ring_cfg);
> +       DMA_RING_ADDRL_SET(ring_cfg, addr);
> +       DMA_RING_ADDRH_SET(ring_cfg, addr);
> +       DMA_RING_SIZE_SET(ring_cfg, ring->cfgsize);
> +
> +       /* Write DMA ring configurations */
> +       xgene_dma_wr_ring_state(ring);
> +
> +       /* Set DMA ring id */
> +       iowrite32(DMA_RING_ID_SETUP(ring->id),
> +                 ring->pdma->csr_ring + DMA_RING_ID);
> +
> +       /* Set DMA ring buffer */
> +       iowrite32(DMA_RING_ID_BUF_SETUP(ring->num),
> +                 ring->pdma->csr_ring + DMA_RING_ID_BUF);
> +
> +       if (ring->owner != DMA_RING_OWNER_CPU)
> +               return;
> +
> +       /* Set empty signature to DMA Rx ring descriptors */
> +       for (i = 0; i < ring->slots; i++) {
> +               desc = &ring->desc_hw[i];
> +               DMA_DESC_SET_EMPTY(desc);
> +       }
> +
> +       /* Enable DMA Rx ring interrupt */
> +       val = ioread32(ring->pdma->csr_ring + DMA_RING_NE_INT_MODE);
> +       DMA_RING_NE_INT_MODE_SET(val, ring->buf_num);
> +       iowrite32(val, ring->pdma->csr_ring + DMA_RING_NE_INT_MODE);
> +}
> +
> +static void xgene_dma_clear_ring(struct xgene_dma_ring *ring)
> +{
> +       u32 ring_id, val;
> +
> +       if (ring->owner == DMA_RING_OWNER_CPU) {
> +               /* Disable DMA Rx ring interrupt */
> +               val = ioread32(ring->pdma->csr_ring + DMA_RING_NE_INT_MODE);
> +               DMA_RING_NE_INT_MODE_RESET(val, ring->buf_num);
> +               iowrite32(val, ring->pdma->csr_ring + DMA_RING_NE_INT_MODE);
> +       }
> +
> +       /* Clear DMA ring state */
> +       ring_id = DMA_RING_ID_SETUP(ring->id);
> +       iowrite32(ring_id, ring->pdma->csr_ring + DMA_RING_ID);
> +
> +       iowrite32(0, ring->pdma->csr_ring + DMA_RING_ID_BUF);
> +       xgene_dma_clr_ring_state(ring);
> +}
> +
> +static void xgene_dma_set_ring_cmd(struct xgene_dma_ring *ring)
> +{
> +       ring->cmd_base = ring->pdma->csr_ring_cmd +
> +                       DMA_RING_CMD_BASE_OFFSET((ring->num - DMA_RING_NUM));
> +       ring->cmd = ring->cmd_base + DMA_RING_CMD_OFFSET;
> +}
> +
> +static int xgene_dma_get_ring_size(struct xgene_dma_chan *chan,
> +                                  enum xgene_dma_ring_cfgsize cfgsize)
> +{
> +       int size;
> +
> +       switch (cfgsize) {
> +       case DMA_RING_CFG_SIZE_512B:
> +               size = 0x200;
> +               break;
> +       case DMA_RING_CFG_SIZE_2KB:
> +               size = 0x800;
> +               break;
> +       case DMA_RING_CFG_SIZE_16KB:
> +               size = 0x4000;
> +               break;
> +       case DMA_RING_CFG_SIZE_64KB:
> +               size = 0x10000;
> +               break;
> +       case DMA_RING_CFG_SIZE_512KB:
> +               size = 0x80000;
> +               break;
> +       default:
> +               chan_err(chan, "Unsupported cfg ring size %d\n", cfgsize);
> +               return -EINVAL;
> +       }
> +
> +       return size;
> +}
> +
> +static void xgene_dma_delete_ring_one(struct xgene_dma_ring *ring)
> +{
> +       /* Clear DMA ring configurations */
> +       xgene_dma_clear_ring(ring);
> +
> +       /* De-allocate DMA ring descriptor */
> +       if (ring->desc_vaddr) {
> +               dma_free_coherent(ring->pdma->dev, ring->size,
> +                                 ring->desc_vaddr, ring->desc_paddr);
> +               ring->desc_vaddr = NULL;
> +       }
> +}
> +
> +static void xgene_dma_delete_chan_rings(struct xgene_dma_chan *chan)
> +{
> +       xgene_dma_delete_ring_one(&chan->rx_ring);
> +       xgene_dma_delete_ring_one(&chan->tx_ring);
> +}
> +
> +static int xgene_dma_create_ring_one(struct xgene_dma_chan *chan,
> +                                    struct xgene_dma_ring *ring,
> +                                    enum xgene_dma_ring_cfgsize cfgsize)
> +{
> +       /* Setup DMA ring descriptor variables */
> +       ring->pdma = chan->pdma;
> +       ring->cfgsize = cfgsize;
> +       ring->num = chan->pdma->ring_num++;
> +       ring->id = DMA_RING_ID_GET(ring->owner, ring->buf_num);
> +
> +       ring->size = xgene_dma_get_ring_size(chan, cfgsize);
> +       if (ring->size <= 0)
> +               return ring->size;
> +
> +       /* Allocate memory for DMA ring descriptor */
> +       ring->desc_vaddr = dma_zalloc_coherent(chan->dev, ring->size,
> +                                              &ring->desc_paddr, GFP_KERNEL);
> +       if (!ring->desc_vaddr) {
> +               chan_err(chan, "Failed to allocate ring desc\n");
> +               return -ENOMEM;
> +       }
> +
> +       /* Configure and enable DMA ring */
> +       xgene_dma_set_ring_cmd(ring);
> +       xgene_dma_setup_ring(ring);
> +
> +       return 0;
> +}
> +
> +static int xgene_dma_create_chan_rings(struct xgene_dma_chan *chan)
> +{
> +       struct xgene_dma_ring *rx_ring = &chan->rx_ring;
> +       struct xgene_dma_ring *tx_ring = &chan->tx_ring;
> +       int ret;
> +
> +       /* Create DMA Rx ring descriptor */
> +       rx_ring->owner = DMA_RING_OWNER_CPU;
> +       rx_ring->buf_num = DMA_CPU_BUFNUM + chan->id;
> +
> +       ret = xgene_dma_create_ring_one(chan, rx_ring, DMA_RING_CFG_SIZE_64KB);
> +       if (ret)
> +               return ret;
> +
> +       chan_dbg(chan, "Rx ring id 0x%X num %d desc 0x%p\n",
> +                rx_ring->id, rx_ring->num, rx_ring->desc_vaddr);
> +
> +       /* Create DMA Tx ring descriptor */
> +       tx_ring->owner = DMA_RING_OWNER_DMA;
> +       tx_ring->buf_num = DMA_BUFNUM + chan->id;
> +
> +       ret = xgene_dma_create_ring_one(chan, tx_ring, DMA_RING_CFG_SIZE_64KB);
> +       if (ret) {
> +               xgene_dma_delete_ring_one(rx_ring);
> +               return ret;
> +       }
> +
> +       tx_ring->dst_ring_num = DMA_RING_DST_ID(rx_ring->num);
> +
> +       chan_dbg(chan,
> +                "Tx ring id 0x%X num %d desc 0x%p\n",
> +                tx_ring->id, tx_ring->num, tx_ring->desc_vaddr);
> +
> +       return ret;
> +}
> +
> +static int xgene_dma_init_rings(struct xgene_dma *pdma)
> +{
> +       int ret, i, j;
> +
> +       for (i = 0; i < DMA_MAX_CHANNEL; i++) {
> +               ret = xgene_dma_create_chan_rings(&pdma->chan[i]);
> +               if (ret) {
> +                       for (j = 0; j < i; j++)
> +                               xgene_dma_delete_chan_rings(&pdma->chan[j]);
> +                       return ret;
> +               }
> +       }
> +
> +       return ret;
> +}
> +
> +static void xgene_dma_enable(struct xgene_dma *pdma)
> +{
> +       u32 val;
> +
> +       /* Configure and enable DMA engine */
> +       val = ioread32(pdma->csr_dma + DMA_GCR);
> +       DMA_CH_SETUP(val);
> +       DMA_ENABLE(val);
> +       iowrite32(val, pdma->csr_dma + DMA_GCR);
> +}
> +
> +static void xgene_dma_disable(struct xgene_dma *pdma)
> +{
> +       u32 val;
> +
> +       val = ioread32(pdma->csr_dma + DMA_GCR);
> +       DMA_DISABLE(val);
> +       iowrite32(val, pdma->csr_dma + DMA_GCR);
> +}
> +
> +static void xgene_dma_mask_interrupts(struct xgene_dma *pdma)
> +{
> +       /*
> +        * Mask DMA ring overflow, underflow and
> +        * AXI write/read error interrupts
> +        */
> +       iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_RING_INT0_MASK);
> +       iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_RING_INT1_MASK);
> +       iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_RING_INT2_MASK);
> +       iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_RING_INT3_MASK);
> +       iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_RING_INT4_MASK);
> +
> +       /* Mask DMA error interrupts */
> +       iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_INT_MASK);
> +}
> +
> +static void xgene_dma_unmask_interrupts(struct xgene_dma *pdma)
> +{
> +       /*
> +        * Unmask DMA ring overflow, underflow and
> +        * AXI write/read error interrupts
> +        */
> +       iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_RING_INT0_MASK);
> +       iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_RING_INT1_MASK);
> +       iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_RING_INT2_MASK);
> +       iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_RING_INT3_MASK);
> +       iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_RING_INT4_MASK);
> +
> +       /* Unmask DMA error interrupts */
> +       iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_INT_MASK);
> +}
> +
> +static void xgene_dma_init_hw(struct xgene_dma *pdma)
> +{
> +       u32 val;
> +
> +       /* Associate DMA ring to corresponding ring HW */
> +       iowrite32(DMA_ASSOC_RING_MNGR1,
> +                 pdma->csr_dma + DMA_CFG_RING_WQ_ASSOC);
> +
> +       xgene_dma_enable(pdma);
> +       xgene_dma_unmask_interrupts(pdma);
> +
> +       /* Get DMA id and version info */
> +       val = ioread32(pdma->csr_dma + DMA_IPBRR);
> +
> +       /* DMA device info */
> +       dev_info(pdma->dev,
> +                "X-Gene DMA v%d.%02d.%02d driver registered %d channels",
> +                DMA_REV_NO_RD(val), DMA_BUS_ID_RD(val),
> +                DMA_DEV_ID_RD(val), DMA_MAX_CHANNEL);
> +}
> +
> +int xgene_dma_init_ring_mngr(struct xgene_dma *pdma)
> +{
> +       if (ioread32(pdma->csr_ring + DMA_RING_CLKEN) &&
> +           (!ioread32(pdma->csr_ring + DMA_RING_SRST)))
> +               return 0;
> +
> +       iowrite32(0x3, pdma->csr_ring + DMA_RING_CLKEN);
> +       iowrite32(0x0, pdma->csr_ring + DMA_RING_SRST);
> +
> +       /* Bring up memory */
> +       iowrite32(0x0, pdma->csr_ring + DMA_RING_MEM_RAM_SHUTDOWN);
> +
> +       /* Force a barrier */
> +       ioread32(pdma->csr_ring + DMA_RING_MEM_RAM_SHUTDOWN);
> +
> +       /* reset may take up to 1ms */
> +       usleep_range(1000, 1100);
> +
> +       if (ioread32(pdma->csr_ring + DMA_RING_BLK_MEM_RDY)
> +               != DMA_RING_BLK_MEM_RDY_VAL) {
> +               dev_err(pdma->dev,
> +                       "Failed to release ring mngr memory from shutdown\n");
> +               return -ENODEV;
> +       }
> +
> +       /* program threshold set 1 and all hysteresis */
> +       iowrite32(DMA_RING_THRESLD0_SET1_VAL,
> +                 pdma->csr_ring + DMA_RING_THRESLD0_SET1);
> +       iowrite32(DMA_RING_THRESLD1_SET1_VAL,
> +                 pdma->csr_ring + DMA_RING_THRESLD1_SET1);
> +       iowrite32(DMA_RING_HYSTERESIS_VAL,
> +                 pdma->csr_ring + DMA_RING_HYSTERESIS);
> +
> +       /* Enable QPcore and assign error queue */
> +       iowrite32(DMA_RING_ENABLE, pdma->csr_ring + DMA_RING_CONFIG);
> +
> +       return 0;
> +}
> +
> +static int xgene_dma_init_mem(struct xgene_dma *pdma)
> +{
> +       int ret;
> +
> +       ret = xgene_dma_init_ring_mngr(pdma);
> +       if (ret)
> +               return ret;
> +
> +       /* Bring up memory */
> +       iowrite32(0x0, pdma->csr_dma + DMA_MEM_RAM_SHUTDOWN);
> +
> +       /* Force a barrier */
> +       ioread32(pdma->csr_dma + DMA_MEM_RAM_SHUTDOWN);
> +
> +       /* reset may take up to 1ms */
> +       usleep_range(1000, 1100);
> +
> +       if (ioread32(pdma->csr_dma + DMA_BLK_MEM_RDY)
> +               != DMA_BLK_MEM_RDY_VAL) {
> +               dev_err(pdma->dev,
> +                       "Failed to release DMA memory from shutdown\n");
> +               return -ENODEV;
> +       }
> +
> +       return 0;
> +}
> +
> +static int xgene_dma_request_irqs(struct xgene_dma *pdma)
> +{
> +       struct xgene_dma_chan *chan;
> +       int ret, i, j;
> +
> +       /* Register DMA error irq */
> +       ret = devm_request_irq(pdma->dev, pdma->err_irq, xgene_dma_err_isr,
> +                              0, "dma_error", pdma);
> +       if (ret) {
> +               dev_err(pdma->dev,
> +                       "Failed to register error IRQ %d\n", pdma->err_irq);
> +               return ret;
> +       }
> +
> +       /* Register DMA channel rx irq */
> +       for (i = 0; i < DMA_MAX_CHANNEL; i++) {
> +               chan = &pdma->chan[i];
> +               ret = devm_request_irq(chan->dev, chan->rx_irq,
> +                                      xgene_dma_chan_ring_isr,
> +                                      0, chan->name, chan);
> +               if (ret) {
> +                       chan_err(chan, "Failed to register Rx IRQ %d\n",
> +                                chan->rx_irq);
> +                       devm_free_irq(pdma->dev, pdma->err_irq, pdma);
> +
> +                       for (j = 0; j < i; j++) {
> +                               chan = &pdma->chan[i];
> +                               devm_free_irq(chan->dev, chan->rx_irq, chan);
> +                       }
> +
> +                       return ret;
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +static void xgene_dma_free_irqs(struct xgene_dma *pdma)
> +{
> +       struct xgene_dma_chan *chan;
> +       int i;
> +
> +       /* Free DMA device error irq */
> +       devm_free_irq(pdma->dev, pdma->err_irq, pdma);
> +
> +       for (i = 0; i < DMA_MAX_CHANNEL; i++) {
> +               chan = &pdma->chan[i];
> +               devm_free_irq(chan->dev, chan->rx_irq, chan);
> +       }
> +}
> +
> +static void xgene_dma_set_caps(struct xgene_dma_chan *chan,
> +                              struct dma_device *dma_dev)
> +{
> +       /* Initialize DMA device capability mask */
> +       dma_cap_zero(dma_dev->cap_mask);
> +
> +       /* Set DMA device capability */
> +       dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
> +       dma_cap_set(DMA_SG, dma_dev->cap_mask);
> +
> +       /* Set base and prep routines */
> +       dma_dev->dev = chan->dev;
> +       dma_dev->device_alloc_chan_resources = xgene_dma_alloc_chan_resources;
> +       dma_dev->device_free_chan_resources = xgene_dma_free_chan_resources;
> +       dma_dev->device_issue_pending = xgene_dma_issue_pending;
> +       dma_dev->device_tx_status = xgene_dma_tx_status;
> +       dma_dev->device_prep_dma_memcpy = xgene_dma_prep_memcpy;
> +       dma_dev->device_prep_dma_sg = xgene_dma_prep_sg;
> +}
> +
> +static int xgene_dma_async_register(struct xgene_dma *pdma, int id)
> +{
> +       struct xgene_dma_chan *chan = &pdma->chan[id];
> +       struct dma_device *dma_dev = &pdma->dma_dev[id];
> +       int ret;
> +
> +       chan->dma_chan.device = dma_dev;
> +
> +       spin_lock_init(&chan->lock);
> +       INIT_LIST_HEAD(&chan->ld_pending);
> +       INIT_LIST_HEAD(&chan->ld_running);
> +       INIT_LIST_HEAD(&chan->ld_completed);
> +       tasklet_init(&chan->tasklet, xgene_dma_tasklet_cb,
> +                    (unsigned long)chan);
> +
> +       chan->pending = 0;
> +       chan->desc_pool = NULL;
> +       dma_cookie_init(&chan->dma_chan);
> +
> +       /* Setup dma device capabilities and prep routines */
> +       xgene_dma_set_caps(chan, dma_dev);
> +
> +       /* Initialize DMA device list head */
> +       INIT_LIST_HEAD(&dma_dev->channels);
> +       list_add_tail(&chan->dma_chan.device_node, &dma_dev->channels);
> +
> +       /* Register with Linux async DMA framework*/
> +       ret = dma_async_device_register(dma_dev);
> +       if (ret) {
> +               chan_err(chan, "Failed to register async device %d", ret);
> +               tasklet_kill(&chan->tasklet);
> +
> +               return ret;
> +       }
> +
> +       /* DMA capability info */
> +       dev_info(pdma->dev,
> +                "%s: CAPABILITY ( %s%s)\n", dma_chan_name(&chan->dma_chan),
> +                dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask) ? "MEMCPY " : "",
> +                dma_has_cap(DMA_SG, dma_dev->cap_mask) ? "SGCPY " : "");
> +
> +       return 0;
> +}
> +
> +static int xgene_dma_init_async(struct xgene_dma *pdma)
> +{
> +       int ret, i, j;
> +
> +       for (i = 0; i < DMA_MAX_CHANNEL ; i++) {
> +               ret = xgene_dma_async_register(pdma, i);
> +               if (ret) {
> +                       for (j = 0; j < i; j++) {
> +                               dma_async_device_unregister(&pdma->dma_dev[j]);
> +                               tasklet_kill(&pdma->chan[j].tasklet);
> +                       }
> +
> +                       return ret;
> +               }
> +       }
> +
> +       return ret;
> +}
> +
> +static void xgene_dma_async_unregister(struct xgene_dma *pdma)
> +{
> +       int i;
> +
> +       for (i = 0; i < DMA_MAX_CHANNEL; i++)
> +               dma_async_device_unregister(&pdma->dma_dev[i]);
> +}
> +
> +static void xgene_dma_init_channels(struct xgene_dma *pdma)
> +{
> +       struct xgene_dma_chan *chan;
> +       int i;
> +
> +       pdma->ring_num = DMA_RING_NUM;
> +
> +       for (i = 0; i < DMA_MAX_CHANNEL; i++) {
> +               chan = &pdma->chan[i];
> +               chan->dev = pdma->dev;
> +               chan->pdma = pdma;
> +               chan->id = i;
> +               sprintf(chan->name, "chan%d", chan->id);
> +       }
> +}
> +
> +static int xgene_dma_get_resources(struct platform_device *pdev,
> +                                  struct xgene_dma *pdma)
> +{
> +       struct resource *res;
> +       int irq, i;
> +
> +       /* Get DMA csr region */
> +       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dma_csr");
> +       if (!res) {
> +               dev_err(&pdev->dev, "Failed to get csr region\n");
> +               return -ENXIO;
> +       }
> +
> +       pdma->csr_dma = devm_ioremap(&pdev->dev, res->start,
> +                                    resource_size(res));
> +       if (IS_ERR(pdma->csr_dma)) {
> +               dev_err(&pdev->dev, "Failed to ioremap csr region");
> +               return PTR_ERR(pdma->csr_dma);
> +       }
> +
> +       /* Get DMA ring csr region */
> +       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ring_csr");
> +       if (!res) {
> +               dev_err(&pdev->dev, "Failed to get ring csr region\n");
> +               return -ENXIO;
> +       }
> +
> +       pdma->csr_ring =  devm_ioremap(&pdev->dev, res->start,
> +                                      resource_size(res));
> +       if (IS_ERR(pdma->csr_ring)) {
> +               dev_err(&pdev->dev, "Failed to ioremap ring csr region");
> +               return PTR_ERR(pdma->csr_ring);
> +       }
> +
> +       /* Get DMA ring cmd csr region */
> +       res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> +                                          "ring_cmd_csr");
> +       if (!res) {
> +               dev_err(&pdev->dev, "Failed to get ring cmd csr region\n");
> +               return -ENXIO;
> +       }
> +
> +       pdma->csr_ring_cmd = devm_ioremap(&pdev->dev, res->start,
> +                                         resource_size(res));
> +       if (IS_ERR(pdma->csr_ring_cmd)) {
> +               dev_err(&pdev->dev, "Failed to ioremap ring cmd csr region");
> +               return PTR_ERR(pdma->csr_ring_cmd);
> +       }
> +
> +       /* Get DMA error interrupt */
> +       irq = platform_get_irq(pdev, 0);
> +       if (irq <= 0) {
> +               dev_err(&pdev->dev, "Failed to get Error IRQ\n");
> +               return -ENXIO;
> +       }
> +
> +       pdma->err_irq = irq;
> +
> +       /* Get DMA Rx ring descriptor interrupts for all DMA channels */
> +       for (i = 1; i <= DMA_MAX_CHANNEL; i++) {
> +               irq = platform_get_irq(pdev, i);
> +               if (irq <= 0) {
> +                       dev_err(&pdev->dev, "Failed to get Rx IRQ\n");
> +                       return -ENXIO;
> +               }
> +
> +               pdma->chan[i - 1].rx_irq = irq;
> +       }
> +
> +       return 0;
> +}
> +
> +static int xgene_dma_probe(struct platform_device *pdev)
> +{
> +       struct xgene_dma *pdma;
> +       int ret, i;
> +
> +       pdma = devm_kzalloc(&pdev->dev, sizeof(*pdma), GFP_KERNEL);
> +       if (!pdma)
> +               return -ENOMEM;
> +
> +       pdma->dev = &pdev->dev;
> +       platform_set_drvdata(pdev, pdma);
> +
> +       ret = xgene_dma_get_resources(pdev, pdma);
> +       if (ret)
> +               return ret;
> +
> +       pdma->clk = devm_clk_get(&pdev->dev, NULL);
> +       if (IS_ERR(pdma->clk)) {
> +               dev_err(&pdev->dev, "Failed to get clk\n");
> +               return PTR_ERR(pdma->clk);
> +       }
> +
> +       /* Enable clk before accessing registers */
> +       ret = clk_prepare_enable(pdma->clk);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Failed to enable clk %d\n", ret);
> +               return ret;
> +       }
> +
> +       /* Remove DMA RAM out of shutdown */
> +       ret = xgene_dma_init_mem(pdma);
> +       if (ret)
> +               goto err_clk_enable;
> +
> +       ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(42));
> +       if (ret) {
> +               dev_err(&pdev->dev, "No usable DMA configuration\n");
> +               goto err_dma_mask;
> +       }
> +
> +       /* Initialize DMA channels software state */
> +       xgene_dma_init_channels(pdma);
> +
> +       /* Configue DMA rings */
> +       ret = xgene_dma_init_rings(pdma);
> +       if (ret)
> +               goto err_clk_enable;
> +
> +       ret = xgene_dma_request_irqs(pdma);
> +       if (ret)
> +               goto err_request_irq;
> +
> +       /* Configure and enable DMA engine */
> +       xgene_dma_init_hw(pdma);
> +
> +       /* Register DMA device with linux async framework */
> +       ret = xgene_dma_init_async(pdma);
> +       if (ret)
> +               goto err_async_init;
> +
> +       return 0;
> +
> +err_async_init:
> +       xgene_dma_free_irqs(pdma);
> +
> +err_request_irq:
> +       for (i = 0; i < DMA_MAX_CHANNEL; i++)
> +               xgene_dma_delete_chan_rings(&pdma->chan[i]);
> +
> +err_dma_mask:
> +err_clk_enable:
> +       clk_disable_unprepare(pdma->clk);
> +
> +       return ret;
> +}
> +
> +static int xgene_dma_remove(struct platform_device *pdev)
> +{
> +       struct xgene_dma *pdma = platform_get_drvdata(pdev);
> +       struct xgene_dma_chan *chan;
> +       int i;
> +
> +       xgene_dma_async_unregister(pdma);
> +
> +       /* Mask interrupts and disable DMA engine */
> +       xgene_dma_mask_interrupts(pdma);
> +       xgene_dma_disable(pdma);
> +       xgene_dma_free_irqs(pdma);
> +
> +       for (i = 0; i < DMA_MAX_CHANNEL; i++) {
> +               chan = &pdma->chan[i];
> +               tasklet_kill(&chan->tasklet);
> +               xgene_dma_delete_chan_rings(chan);
> +       }
> +
> +       clk_disable_unprepare(pdma->clk);
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id xgene_dma_of_match_ptr[] = {
> +       {.compatible = "apm,xgene-dma",},
> +       {},
> +};
> +MODULE_DEVICE_TABLE(of, xgene_dma_of_match_ptr);
> +
> +static struct platform_driver xgene_dma_driver = {
> +       .probe = xgene_dma_probe,
> +       .remove = xgene_dma_remove,
> +       .driver = {
> +               .name = "X-Gene-DMA",
> +               .owner = THIS_MODULE,
> +               .of_match_table = xgene_dma_of_match_ptr,
> +       },
> +};
> +
> +module_platform_driver(xgene_dma_driver);
> +
> +MODULE_DESCRIPTION("APM X-Gene SoC DMA driver");
> +MODULE_AUTHOR("Rameshwar Prasad Sahu <[e-mail]>");
> +MODULE_AUTHOR("Loc Ho <[e-mail]>");
> +MODULE_LICENSE("GPL");
> +MODULE_VERSION("1.0");
> --
> 1.8.2.1
>

any comments on above patch.

Thanks,
with regards,
Ram
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Ben Dooks Feb. 26, 2015, 2:25 p.m. UTC | #2

On 26/02/15 12:31, Rameshwar Sahu wrote:
> Hi Vinod,
> 
> 
> On Tue, Feb 24, 2015 at 6:23 PM, Rameshwar Prasad Sahu <[e-mail]> wrote:
>> This patch implements the APM X-Gene SoC DMA engine driver. The APM X-Gene
>> SoC DMA engine consists of 4 DMA channels for performing DMA operations.
>> These DMA operations include memory copy and scatter-gather memory copy
>> offloading.
>>
>> Signed-off-by: Rameshwar Prasad Sahu <[e-mail]>
>> Signed-off-by: Loc Ho <[e-mail]>
>> ---
>>  drivers/dma/Kconfig     |    8 +
>>  drivers/dma/Makefile    |    1 +
>>  drivers/dma/xgene-dma.c | 1738 +++++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 1747 insertions(+)
>>  create mode 100755 drivers/dma/xgene-dma.c
>>
>> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
>> index a874b6e..0e05831 100644
>> --- a/drivers/dma/Kconfig
>> +++ b/drivers/dma/Kconfig
>> @@ -425,6 +425,14 @@ config IMG_MDC_DMA
>>         help
>>           Enable support for the IMG multi-threaded DMA controller (MDC).
>>
>> +config XGENE_DMA
>> +       tristate "APM X-Gene DMA support"
>> +       depends on ARCH_XGENE
>> +       select DMA_ENGINE
>> +       select ASYNC_TX_ENABLE_CHANNEL_SWITCH
>> +       help
>> +         Enable support for the APM X-Gene SoC DMA engine.
>> +
>>  config DMA_ENGINE
>>         bool
>>
>> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
>> index f915f61..06c1576 100644
>> --- a/drivers/dma/Makefile
>> +++ b/drivers/dma/Makefile
>> @@ -51,3 +51,4 @@ obj-$(CONFIG_INTEL_MIC_X100_DMA) += mic_x100_dma.o
>>  obj-$(CONFIG_NBPFAXI_DMA) += nbpfaxi.o
>>  obj-$(CONFIG_DMA_SUN6I) += sun6i-dma.o
>>  obj-$(CONFIG_IMG_MDC_DMA) += img-mdc-dma.o
>> +obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
>> diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
>> new file mode 100755
>> index 0000000..e736c2e
>> --- /dev/null
>> +++ b/drivers/dma/xgene-dma.c
>> @@ -0,0 +1,1738 @@
>> +/*
>> + * Applied Micro X-Gene SoC DMA engine Driver
>> + *
>> + * Copyright (c) 2015, Applied Micro Circuits Corporation
>> + * Authors: Rameshwar Prasad Sahu <[e-mail]>
>> + *         Loc Ho <[e-mail]>
>> + *
>> + * This program is free software; you can redistribute  it and/or modify it
>> + * under  the terms of  the GNU General  Public License as published by the
>> + * Free Software Foundation;  either version 2 of the  License, or (at your
>> + * option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>> + *
>> + * NOTE: PM support is currently not available.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/delay.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/dmaengine.h>
>> +#include <linux/dmapool.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/io.h>
>> +#include <linux/module.h>
>> +#include <linux/of_device.h>
>> +
>> +#include "dmaengine.h"
>> +
>> +/* DMA ring csr registers and bit definations */
>> +#define DMA_RING_CONFIG                        0x04
>> +#define DMA_RING_ENABLE                        BIT(31)
>> +#define DMA_RING_ID                    0x08
>> +#define DMA_RING_ID_SETUP(v)           ((v) | BIT(31))
>> +#define DMA_RING_ID_BUF                        0x0C
>> +#define DMA_RING_ID_BUF_SETUP(v)       (((v) << 9) | BIT(21))
>> +#define DMA_RING_THRESLD0_SET1         0x30
>> +#define DMA_RING_THRESLD0_SET1_VAL     0X64
>> +#define DMA_RING_THRESLD1_SET1         0x34
>> +#define DMA_RING_THRESLD1_SET1_VAL     0xC8
>> +#define DMA_RING_HYSTERESIS            0x68
>> +#define DMA_RING_HYSTERESIS_VAL                0xFFFFFFFF
>> +#define DMA_RING_STATE                 0x6C
>> +#define DMA_RING_STATE_WR_BASE         0x70
>> +#define DMA_RING_NE_INT_MODE           0x017C
>> +#define DMA_RING_NE_INT_MODE_SET(m, v) \
>> +       ((m) = ((m) & ~BIT(31 - (v))) | BIT(31 - (v)))
>> +#define DMA_RING_NE_INT_MODE_RESET(m, v)       \
>> +       ((m) &= (~BIT(31 - (v))))
>> +#define DMA_RING_CLKEN                 0xC208
>> +#define DMA_RING_SRST                  0xC200
>> +#define DMA_RING_MEM_RAM_SHUTDOWN      0xD070
>> +#define DMA_RING_BLK_MEM_RDY           0xD074
>> +#define DMA_RING_BLK_MEM_RDY_VAL       0xFFFFFFFF
>> +#define DMA_RING_DESC_CNT(v)           (((v) & 0x0001FFFE) >> 1)
>> +#define DMA_RING_ID_GET(owner, num)    (((owner) << 6) | (num))
>> +#define DMA_RING_DST_ID(v)             ((1 << 10) | (v))
>> +#define DMA_RING_CMD_OFFSET            0x2C
>> +#define DMA_RING_CMD_BASE_OFFSET(v)    ((v) << 6)
>> +#define DMA_RING_COHERENT_SET(m)       (((u32 *)(m))[2] |= BIT(4))
>> +#define DMA_RING_ADDRL_SET(m, v)       (((u32 *)(m))[2] |= (((v) >> 8) << 5))
>> +#define DMA_RING_ADDRH_SET(m, v)       (((u32 *)(m))[3] |= ((v) >> 35))
>> +#define DMA_RING_ACCEPTLERR_SET(m)     (((u32 *)(m))[3] |= BIT(19))
>> +#define DMA_RING_SIZE_SET(m, v)                (((u32 *)(m))[3] |= ((v) << 23))
>> +#define DMA_RING_RECOMBBUF_SET(m)      (((u32 *)(m))[3] |= BIT(27))
>> +#define DMA_RING_RECOMTIMEOUTL_SET(m)  (((u32 *)(m))[3] |= (0x7 << 28))
>> +#define DMA_RING_RECOMTIMEOUTH_SET(m)  (((u32 *)(m))[4] |= 0x3)
>> +#define DMA_RING_SELTHRSH_SET(m)       (((u32 *)(m))[4] |= BIT(3))
>> +#define DMA_RING_TYPE_SET(m, v)                (((u32 *)(m))[4] |= ((v) << 19))
>> +
>> +/* DMA device csr registers and bit definitions */
>> +#define DMA_IPBRR              0x0
>> +#define DMA_DEV_ID_RD(v)       ((v) & 0x00000FFF)
>> +#define DMA_BUS_ID_RD(v)       (((v) >> 12) & 3)
>> +#define DMA_REV_NO_RD(v)       (((v) >> 14) & 3)
>> +#define DMA_GCR                        0x10
>> +#define DMA_CH_SETUP(v)                ((v) = ((v) & ~0x000FFFFF) | 0x000AAFFF)
>> +#define DMA_ENABLE(v)          ((v) |= BIT(31))
>> +#define DMA_DISABLE(v)         ((v) &= ~BIT(31))
>> +#define DMA_INT                        0x70
>> +#define DMA_INT_MASK           0x74
>> +#define DMA_INT_ALL_MASK       0xFFFFFFFF
>> +#define DMA_INT_ALL_UNMASK     0x0
>> +#define DMA_INT_MASK_SHIFT     0x14
>> +#define DMA_RING_INT0_MASK     0x90A0
>> +#define DMA_RING_INT1_MASK     0x90A8
>> +#define DMA_RING_INT2_MASK     0x90B0
>> +#define DMA_RING_INT3_MASK     0x90B8
>> +#define DMA_RING_INT4_MASK     0x90C0
>> +#define DMA_CFG_RING_WQ_ASSOC  0x90E0
>> +#define DMA_ASSOC_RING_MNGR1   0xFFFFFFFF
>> +#define DMA_MEM_RAM_SHUTDOWN   0xD070
>> +#define DMA_BLK_MEM_RDY                0xD074
>> +#define DMA_BLK_MEM_RDY_VAL    0xFFFFFFFF
>> +
>> +/* DMA Descriptor format */
>> +#define DMA_DESC_ELERR_RD(m)           (((m) >> 46) & 0x3)
>> +#define DMA_DESC_NV_SET(m)             (((u64 *)(m))[0] |= BIT_ULL(50))
>> +#define DMA_DESC_IN_SET(m)             (((u64 *)(m))[0] |= BIT_ULL(55))
>> +#define DMA_DESC_RTYPE_SET(m, v)       (((u64 *)(m))[0] |= ((u64)(v) << 56))
>> +#define DMA_DESC_LERR_RD(m)            (((m) >> 60) & 0x7)
>> +#define DMA_DESC_BUFADDR_SET(m, v)     (((u64 *)(m))[0] |= (v))
>> +#define DMA_DESC_BUFLEN_SET(m, v)      (((u64 *)(m))[0] |= ((u64)(v) << 48))
>> +#define DMA_DESC_C_SET(m)              (((u64 *)(m))[1] |= BIT_ULL(63))
>> +#define DMA_DESC_DR_SET(m)             (((u64 *)(m))[2] |= BIT_ULL(61))
>> +#define DMA_DESC_DST_ADDR_SET(m, v)    (((u64 *)(m))[3] |= (v))
>> +#define DMA_DESC_H0ENQ_NUM_SET(m, v)   (((u64 *)(m))[3] |= ((u64)(v) << 48))
>> +#define DMA_DESC_STATUS(x, y)          (((x) << 4) | (y))

This is very difficult to read.

Rameshwar Prasad Sahu Feb. 27, 2015, 4:09 a.m. UTC | #3

Hi,


On Thu, Feb 26, 2015 at 7:55 PM, Ben Dooks <[e-mail]> wrote:
> On 26/02/15 12:31, Rameshwar Sahu wrote:
>> Hi Vinod,
>>
>>
>> On Tue, Feb 24, 2015 at 6:23 PM, Rameshwar Prasad Sahu <[e-mail]> wrote:
>>> This patch implements the APM X-Gene SoC DMA engine driver. The APM X-Gene
>>> SoC DMA engine consists of 4 DMA channels for performing DMA operations.
>>> These DMA operations include memory copy and scatter-gather memory copy
>>> offloading.
>>>
>>> Signed-off-by: Rameshwar Prasad Sahu <[e-mail]>
>>> Signed-off-by: Loc Ho <[e-mail]>
>>> ---
>>>  drivers/dma/Kconfig     |    8 +
>>>  drivers/dma/Makefile    |    1 +
>>>  drivers/dma/xgene-dma.c | 1738 +++++++++++++++++++++++++++++++++++++++++++++++
>>>  3 files changed, 1747 insertions(+)
>>>  create mode 100755 drivers/dma/xgene-dma.c
>>>
>>> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
>>> index a874b6e..0e05831 100644
>>> --- a/drivers/dma/Kconfig
>>> +++ b/drivers/dma/Kconfig
>>> @@ -425,6 +425,14 @@ config IMG_MDC_DMA
>>>         help
>>>           Enable support for the IMG multi-threaded DMA controller (MDC).
>>>
>>> +config XGENE_DMA
>>> +       tristate "APM X-Gene DMA support"
>>> +       depends on ARCH_XGENE
>>> +       select DMA_ENGINE
>>> +       select ASYNC_TX_ENABLE_CHANNEL_SWITCH
>>> +       help
>>> +         Enable support for the APM X-Gene SoC DMA engine.
>>> +
>>>  config DMA_ENGINE
>>>         bool
>>>
>>> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
>>> index f915f61..06c1576 100644
>>> --- a/drivers/dma/Makefile
>>> +++ b/drivers/dma/Makefile
>>> @@ -51,3 +51,4 @@ obj-$(CONFIG_INTEL_MIC_X100_DMA) += mic_x100_dma.o
>>>  obj-$(CONFIG_NBPFAXI_DMA) += nbpfaxi.o
>>>  obj-$(CONFIG_DMA_SUN6I) += sun6i-dma.o
>>>  obj-$(CONFIG_IMG_MDC_DMA) += img-mdc-dma.o
>>> +obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
>>> diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
>>> new file mode 100755
>>> index 0000000..e736c2e
>>> --- /dev/null
>>> +++ b/drivers/dma/xgene-dma.c
>>> @@ -0,0 +1,1738 @@
>>> +/*
>>> + * Applied Micro X-Gene SoC DMA engine Driver
>>> + *
>>> + * Copyright (c) 2015, Applied Micro Circuits Corporation
>>> + * Authors: Rameshwar Prasad Sahu <[e-mail]>
>>> + *         Loc Ho <[e-mail]>
>>> + *
>>> + * This program is free software; you can redistribute  it and/or modify it
>>> + * under  the terms of  the GNU General  Public License as published by the
>>> + * Free Software Foundation;  either version 2 of the  License, or (at your
>>> + * option) any later version.
>>> + *
>>> + * This program is distributed in the hope that it will be useful,
>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>>> + * GNU General Public License for more details.
>>> + *
>>> + * You should have received a copy of the GNU General Public License
>>> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>>> + *
>>> + * NOTE: PM support is currently not available.
>>> + */
>>> +
>>> +#include <linux/clk.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/dma-mapping.h>
>>> +#include <linux/dmaengine.h>
>>> +#include <linux/dmapool.h>
>>> +#include <linux/interrupt.h>
>>> +#include <linux/io.h>
>>> +#include <linux/module.h>
>>> +#include <linux/of_device.h>
>>> +
>>> +#include "dmaengine.h"
>>> +
>>> +/* DMA ring csr registers and bit definations */
>>> +#define DMA_RING_CONFIG                        0x04
>>> +#define DMA_RING_ENABLE                        BIT(31)
>>> +#define DMA_RING_ID                    0x08
>>> +#define DMA_RING_ID_SETUP(v)           ((v) | BIT(31))
>>> +#define DMA_RING_ID_BUF                        0x0C
>>> +#define DMA_RING_ID_BUF_SETUP(v)       (((v) << 9) | BIT(21))
>>> +#define DMA_RING_THRESLD0_SET1         0x30
>>> +#define DMA_RING_THRESLD0_SET1_VAL     0X64
>>> +#define DMA_RING_THRESLD1_SET1         0x34
>>> +#define DMA_RING_THRESLD1_SET1_VAL     0xC8
>>> +#define DMA_RING_HYSTERESIS            0x68
>>> +#define DMA_RING_HYSTERESIS_VAL                0xFFFFFFFF
>>> +#define DMA_RING_STATE                 0x6C
>>> +#define DMA_RING_STATE_WR_BASE         0x70
>>> +#define DMA_RING_NE_INT_MODE           0x017C
>>> +#define DMA_RING_NE_INT_MODE_SET(m, v) \
>>> +       ((m) = ((m) & ~BIT(31 - (v))) | BIT(31 - (v)))
>>> +#define DMA_RING_NE_INT_MODE_RESET(m, v)       \
>>> +       ((m) &= (~BIT(31 - (v))))
>>> +#define DMA_RING_CLKEN                 0xC208
>>> +#define DMA_RING_SRST                  0xC200
>>> +#define DMA_RING_MEM_RAM_SHUTDOWN      0xD070
>>> +#define DMA_RING_BLK_MEM_RDY           0xD074
>>> +#define DMA_RING_BLK_MEM_RDY_VAL       0xFFFFFFFF
>>> +#define DMA_RING_DESC_CNT(v)           (((v) & 0x0001FFFE) >> 1)
>>> +#define DMA_RING_ID_GET(owner, num)    (((owner) << 6) | (num))
>>> +#define DMA_RING_DST_ID(v)             ((1 << 10) | (v))
>>> +#define DMA_RING_CMD_OFFSET            0x2C
>>> +#define DMA_RING_CMD_BASE_OFFSET(v)    ((v) << 6)
>>> +#define DMA_RING_COHERENT_SET(m)       (((u32 *)(m))[2] |= BIT(4))
>>> +#define DMA_RING_ADDRL_SET(m, v)       (((u32 *)(m))[2] |= (((v) >> 8) << 5))
>>> +#define DMA_RING_ADDRH_SET(m, v)       (((u32 *)(m))[3] |= ((v) >> 35))
>>> +#define DMA_RING_ACCEPTLERR_SET(m)     (((u32 *)(m))[3] |= BIT(19))
>>> +#define DMA_RING_SIZE_SET(m, v)                (((u32 *)(m))[3] |= ((v) << 23))
>>> +#define DMA_RING_RECOMBBUF_SET(m)      (((u32 *)(m))[3] |= BIT(27))
>>> +#define DMA_RING_RECOMTIMEOUTL_SET(m)  (((u32 *)(m))[3] |= (0x7 << 28))
>>> +#define DMA_RING_RECOMTIMEOUTH_SET(m)  (((u32 *)(m))[4] |= 0x3)
>>> +#define DMA_RING_SELTHRSH_SET(m)       (((u32 *)(m))[4] |= BIT(3))
>>> +#define DMA_RING_TYPE_SET(m, v)                (((u32 *)(m))[4] |= ((v) << 19))
>>> +
>>> +/* DMA device csr registers and bit definitions */
>>> +#define DMA_IPBRR              0x0
>>> +#define DMA_DEV_ID_RD(v)       ((v) & 0x00000FFF)
>>> +#define DMA_BUS_ID_RD(v)       (((v) >> 12) & 3)
>>> +#define DMA_REV_NO_RD(v)       (((v) >> 14) & 3)
>>> +#define DMA_GCR                        0x10
>>> +#define DMA_CH_SETUP(v)                ((v) = ((v) & ~0x000FFFFF) | 0x000AAFFF)
>>> +#define DMA_ENABLE(v)          ((v) |= BIT(31))
>>> +#define DMA_DISABLE(v)         ((v) &= ~BIT(31))
>>> +#define DMA_INT                        0x70
>>> +#define DMA_INT_MASK           0x74
>>> +#define DMA_INT_ALL_MASK       0xFFFFFFFF
>>> +#define DMA_INT_ALL_UNMASK     0x0
>>> +#define DMA_INT_MASK_SHIFT     0x14
>>> +#define DMA_RING_INT0_MASK     0x90A0
>>> +#define DMA_RING_INT1_MASK     0x90A8
>>> +#define DMA_RING_INT2_MASK     0x90B0
>>> +#define DMA_RING_INT3_MASK     0x90B8
>>> +#define DMA_RING_INT4_MASK     0x90C0
>>> +#define DMA_CFG_RING_WQ_ASSOC  0x90E0
>>> +#define DMA_ASSOC_RING_MNGR1   0xFFFFFFFF
>>> +#define DMA_MEM_RAM_SHUTDOWN   0xD070
>>> +#define DMA_BLK_MEM_RDY                0xD074
>>> +#define DMA_BLK_MEM_RDY_VAL    0xFFFFFFFF
>>> +
>>> +/* DMA Descriptor format */
>>> +#define DMA_DESC_ELERR_RD(m)           (((m) >> 46) & 0x3)
>>> +#define DMA_DESC_NV_SET(m)             (((u64 *)(m))[0] |= BIT_ULL(50))
>>> +#define DMA_DESC_IN_SET(m)             (((u64 *)(m))[0] |= BIT_ULL(55))
>>> +#define DMA_DESC_RTYPE_SET(m, v)       (((u64 *)(m))[0] |= ((u64)(v) << 56))
>>> +#define DMA_DESC_LERR_RD(m)            (((m) >> 60) & 0x7)
>>> +#define DMA_DESC_BUFADDR_SET(m, v)     (((u64 *)(m))[0] |= (v))
>>> +#define DMA_DESC_BUFLEN_SET(m, v)      (((u64 *)(m))[0] |= ((u64)(v) << 48))
>>> +#define DMA_DESC_C_SET(m)              (((u64 *)(m))[1] |= BIT_ULL(63))
>>> +#define DMA_DESC_DR_SET(m)             (((u64 *)(m))[2] |= BIT_ULL(61))
>>> +#define DMA_DESC_DST_ADDR_SET(m, v)    (((u64 *)(m))[3] |= (v))
>>> +#define DMA_DESC_H0ENQ_NUM_SET(m, v)   (((u64 *)(m))[3] |= ((u64)(v) << 48))
>>> +#define DMA_DESC_STATUS(x, y)          (((x) << 4) | (y))
>
> This is very difficult to read.
>
In the original source file it is well aligned, when I generate patch
and send, it scattered like this.
>
> --
> Ben Dooks                               http://www.codethink.co.uk/
> Senior Engineer                         Codethink - Providing Genius
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Rameshwar Prasad Sahu Feb. 27, 2015, 6:29 a.m. UTC | #4

Hi


On Fri, Feb 27, 2015 at 9:39 AM, Rameshwar Sahu <[e-mail]> wrote:
> Hi,
>
>
> On Thu, Feb 26, 2015 at 7:55 PM, Ben Dooks <[e-mail]> wrote:
>> On 26/02/15 12:31, Rameshwar Sahu wrote:
>>> Hi Vinod,
>>>
>>>
>>> On Tue, Feb 24, 2015 at 6:23 PM, Rameshwar Prasad Sahu <[e-mail]> wrote:
>>>> This patch implements the APM X-Gene SoC DMA engine driver. The APM X-Gene
>>>> SoC DMA engine consists of 4 DMA channels for performing DMA operations.
>>>> These DMA operations include memory copy and scatter-gather memory copy
>>>> offloading.
>>>>
>>>> Signed-off-by: Rameshwar Prasad Sahu <[e-mail]>
>>>> Signed-off-by: Loc Ho <[e-mail]>
>>>> ---
>>>>  drivers/dma/Kconfig     |    8 +
>>>>  drivers/dma/Makefile    |    1 +
>>>>  drivers/dma/xgene-dma.c | 1738 +++++++++++++++++++++++++++++++++++++++++++++++
>>>>  3 files changed, 1747 insertions(+)
>>>>  create mode 100755 drivers/dma/xgene-dma.c
>>>>
>>>> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
>>>> index a874b6e..0e05831 100644
>>>> --- a/drivers/dma/Kconfig
>>>> +++ b/drivers/dma/Kconfig
>>>> @@ -425,6 +425,14 @@ config IMG_MDC_DMA
>>>>         help
>>>>           Enable support for the IMG multi-threaded DMA controller (MDC).
>>>>
>>>> +config XGENE_DMA
>>>> +       tristate "APM X-Gene DMA support"
>>>> +       depends on ARCH_XGENE
>>>> +       select DMA_ENGINE
>>>> +       select ASYNC_TX_ENABLE_CHANNEL_SWITCH
>>>> +       help
>>>> +         Enable support for the APM X-Gene SoC DMA engine.
>>>> +
>>>>  config DMA_ENGINE
>>>>         bool
>>>>
>>>> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
>>>> index f915f61..06c1576 100644
>>>> --- a/drivers/dma/Makefile
>>>> +++ b/drivers/dma/Makefile
>>>> @@ -51,3 +51,4 @@ obj-$(CONFIG_INTEL_MIC_X100_DMA) += mic_x100_dma.o
>>>>  obj-$(CONFIG_NBPFAXI_DMA) += nbpfaxi.o
>>>>  obj-$(CONFIG_DMA_SUN6I) += sun6i-dma.o
>>>>  obj-$(CONFIG_IMG_MDC_DMA) += img-mdc-dma.o
>>>> +obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
>>>> diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
>>>> new file mode 100755
>>>> index 0000000..e736c2e
>>>> --- /dev/null
>>>> +++ b/drivers/dma/xgene-dma.c
>>>> @@ -0,0 +1,1738 @@
>>>> +/*
>>>> + * Applied Micro X-Gene SoC DMA engine Driver
>>>> + *
>>>> + * Copyright (c) 2015, Applied Micro Circuits Corporation
>>>> + * Authors: Rameshwar Prasad Sahu <[e-mail]>
>>>> + *         Loc Ho <[e-mail]>
>>>> + *
>>>> + * This program is free software; you can redistribute  it and/or modify it
>>>> + * under  the terms of  the GNU General  Public License as published by the
>>>> + * Free Software Foundation;  either version 2 of the  License, or (at your
>>>> + * option) any later version.
>>>> + *
>>>> + * This program is distributed in the hope that it will be useful,
>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>>>> + * GNU General Public License for more details.
>>>> + *
>>>> + * You should have received a copy of the GNU General Public License
>>>> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>>>> + *
>>>> + * NOTE: PM support is currently not available.
>>>> + */
>>>> +
>>>> +#include <linux/clk.h>
>>>> +#include <linux/delay.h>
>>>> +#include <linux/dma-mapping.h>
>>>> +#include <linux/dmaengine.h>
>>>> +#include <linux/dmapool.h>
>>>> +#include <linux/interrupt.h>
>>>> +#include <linux/io.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/of_device.h>
>>>> +
>>>> +#include "dmaengine.h"
>>>> +
>>>> +/* DMA ring csr registers and bit definations */
>>>> +#define DMA_RING_CONFIG                        0x04
>>>> +#define DMA_RING_ENABLE                        BIT(31)
>>>> +#define DMA_RING_ID                    0x08
>>>> +#define DMA_RING_ID_SETUP(v)           ((v) | BIT(31))
>>>> +#define DMA_RING_ID_BUF                        0x0C
>>>> +#define DMA_RING_ID_BUF_SETUP(v)       (((v) << 9) | BIT(21))
>>>> +#define DMA_RING_THRESLD0_SET1         0x30
>>>> +#define DMA_RING_THRESLD0_SET1_VAL     0X64
>>>> +#define DMA_RING_THRESLD1_SET1         0x34
>>>> +#define DMA_RING_THRESLD1_SET1_VAL     0xC8
>>>> +#define DMA_RING_HYSTERESIS            0x68
>>>> +#define DMA_RING_HYSTERESIS_VAL                0xFFFFFFFF
>>>> +#define DMA_RING_STATE                 0x6C
>>>> +#define DMA_RING_STATE_WR_BASE         0x70
>>>> +#define DMA_RING_NE_INT_MODE           0x017C
>>>> +#define DMA_RING_NE_INT_MODE_SET(m, v) \
>>>> +       ((m) = ((m) & ~BIT(31 - (v))) | BIT(31 - (v)))
>>>> +#define DMA_RING_NE_INT_MODE_RESET(m, v)       \
>>>> +       ((m) &= (~BIT(31 - (v))))
>>>> +#define DMA_RING_CLKEN                 0xC208
>>>> +#define DMA_RING_SRST                  0xC200
>>>> +#define DMA_RING_MEM_RAM_SHUTDOWN      0xD070
>>>> +#define DMA_RING_BLK_MEM_RDY           0xD074
>>>> +#define DMA_RING_BLK_MEM_RDY_VAL       0xFFFFFFFF
>>>> +#define DMA_RING_DESC_CNT(v)           (((v) & 0x0001FFFE) >> 1)
>>>> +#define DMA_RING_ID_GET(owner, num)    (((owner) << 6) | (num))
>>>> +#define DMA_RING_DST_ID(v)             ((1 << 10) | (v))
>>>> +#define DMA_RING_CMD_OFFSET            0x2C
>>>> +#define DMA_RING_CMD_BASE_OFFSET(v)    ((v) << 6)
>>>> +#define DMA_RING_COHERENT_SET(m)       (((u32 *)(m))[2] |= BIT(4))
>>>> +#define DMA_RING_ADDRL_SET(m, v)       (((u32 *)(m))[2] |= (((v) >> 8) << 5))
>>>> +#define DMA_RING_ADDRH_SET(m, v)       (((u32 *)(m))[3] |= ((v) >> 35))
>>>> +#define DMA_RING_ACCEPTLERR_SET(m)     (((u32 *)(m))[3] |= BIT(19))
>>>> +#define DMA_RING_SIZE_SET(m, v)                (((u32 *)(m))[3] |= ((v) << 23))
>>>> +#define DMA_RING_RECOMBBUF_SET(m)      (((u32 *)(m))[3] |= BIT(27))
>>>> +#define DMA_RING_RECOMTIMEOUTL_SET(m)  (((u32 *)(m))[3] |= (0x7 << 28))
>>>> +#define DMA_RING_RECOMTIMEOUTH_SET(m)  (((u32 *)(m))[4] |= 0x3)
>>>> +#define DMA_RING_SELTHRSH_SET(m)       (((u32 *)(m))[4] |= BIT(3))
>>>> +#define DMA_RING_TYPE_SET(m, v)                (((u32 *)(m))[4] |= ((v) << 19))
>>>> +
>>>> +/* DMA device csr registers and bit definitions */
>>>> +#define DMA_IPBRR              0x0
>>>> +#define DMA_DEV_ID_RD(v)       ((v) & 0x00000FFF)
>>>> +#define DMA_BUS_ID_RD(v)       (((v) >> 12) & 3)
>>>> +#define DMA_REV_NO_RD(v)       (((v) >> 14) & 3)
>>>> +#define DMA_GCR                        0x10
>>>> +#define DMA_CH_SETUP(v)                ((v) = ((v) & ~0x000FFFFF) | 0x000AAFFF)
>>>> +#define DMA_ENABLE(v)          ((v) |= BIT(31))
>>>> +#define DMA_DISABLE(v)         ((v) &= ~BIT(31))
>>>> +#define DMA_INT                        0x70
>>>> +#define DMA_INT_MASK           0x74
>>>> +#define DMA_INT_ALL_MASK       0xFFFFFFFF
>>>> +#define DMA_INT_ALL_UNMASK     0x0
>>>> +#define DMA_INT_MASK_SHIFT     0x14
>>>> +#define DMA_RING_INT0_MASK     0x90A0
>>>> +#define DMA_RING_INT1_MASK     0x90A8
>>>> +#define DMA_RING_INT2_MASK     0x90B0
>>>> +#define DMA_RING_INT3_MASK     0x90B8
>>>> +#define DMA_RING_INT4_MASK     0x90C0
>>>> +#define DMA_CFG_RING_WQ_ASSOC  0x90E0
>>>> +#define DMA_ASSOC_RING_MNGR1   0xFFFFFFFF
>>>> +#define DMA_MEM_RAM_SHUTDOWN   0xD070
>>>> +#define DMA_BLK_MEM_RDY                0xD074
>>>> +#define DMA_BLK_MEM_RDY_VAL    0xFFFFFFFF
>>>> +
>>>> +/* DMA Descriptor format */
>>>> +#define DMA_DESC_ELERR_RD(m)           (((m) >> 46) & 0x3)
>>>> +#define DMA_DESC_NV_SET(m)             (((u64 *)(m))[0] |= BIT_ULL(50))
>>>> +#define DMA_DESC_IN_SET(m)             (((u64 *)(m))[0] |= BIT_ULL(55))
>>>> +#define DMA_DESC_RTYPE_SET(m, v)       (((u64 *)(m))[0] |= ((u64)(v) << 56))
>>>> +#define DMA_DESC_LERR_RD(m)            (((m) >> 60) & 0x7)
>>>> +#define DMA_DESC_BUFADDR_SET(m, v)     (((u64 *)(m))[0] |= (v))
>>>> +#define DMA_DESC_BUFLEN_SET(m, v)      (((u64 *)(m))[0] |= ((u64)(v) << 48))
>>>> +#define DMA_DESC_C_SET(m)              (((u64 *)(m))[1] |= BIT_ULL(63))
>>>> +#define DMA_DESC_DR_SET(m)             (((u64 *)(m))[2] |= BIT_ULL(61))
>>>> +#define DMA_DESC_DST_ADDR_SET(m, v)    (((u64 *)(m))[3] |= (v))
>>>> +#define DMA_DESC_H0ENQ_NUM_SET(m, v)   (((u64 *)(m))[3] |= ((u64)(v) << 48))
>>>> +#define DMA_DESC_STATUS(x, y)          (((x) << 4) | (y))
>>
>> This is very difficult to read.
>>
> In the original source file it is well aligned, when I generate patch
> and send, it scattered like this.
>>

Sorry I mis interpreted your comments. I will make these above define simpler.
>> --
>> Ben Dooks                               http://www.codethink.co.uk/
>> Senior Engineer                         Codethink - Providing Genius
--
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Patch

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index a874b6e..0e05831 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -425,6 +425,14 @@  config IMG_MDC_DMA
 	help
 	  Enable support for the IMG multi-threaded DMA controller (MDC).

+config XGENE_DMA
+	tristate "APM X-Gene DMA support"
+	depends on ARCH_XGENE
+	select DMA_ENGINE
+	select ASYNC_TX_ENABLE_CHANNEL_SWITCH
+	help
+	  Enable support for the APM X-Gene SoC DMA engine.
+
 config DMA_ENGINE
 	bool

diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index f915f61..06c1576 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -51,3 +51,4 @@  obj-$(CONFIG_INTEL_MIC_X100_DMA) += mic_x100_dma.o
 obj-$(CONFIG_NBPFAXI_DMA) += nbpfaxi.o
 obj-$(CONFIG_DMA_SUN6I) += sun6i-dma.o
 obj-$(CONFIG_IMG_MDC_DMA) += img-mdc-dma.o
+obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
new file mode 100755
index 0000000..e736c2e
--- /dev/null
+++ b/drivers/dma/xgene-dma.c
@@ -0,0 +1,1738 @@ 
+/*
+ * Applied Micro X-Gene SoC DMA engine Driver
+ *
+ * Copyright (c) 2015, Applied Micro Circuits Corporation
+ * Authors: Rameshwar Prasad Sahu <[e-mail]>
+ *	    Loc Ho <[e-mail]>
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * NOTE: PM support is currently not available.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/dmapool.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+#include "dmaengine.h"
+
+/* DMA ring csr registers and bit definations */
+#define DMA_RING_CONFIG			0x04
+#define DMA_RING_ENABLE			BIT(31)
+#define DMA_RING_ID			0x08
+#define DMA_RING_ID_SETUP(v)		((v) | BIT(31))
+#define DMA_RING_ID_BUF			0x0C
+#define DMA_RING_ID_BUF_SETUP(v)	(((v) << 9) | BIT(21))
+#define DMA_RING_THRESLD0_SET1		0x30
+#define DMA_RING_THRESLD0_SET1_VAL	0X64
+#define DMA_RING_THRESLD1_SET1		0x34
+#define DMA_RING_THRESLD1_SET1_VAL	0xC8
+#define DMA_RING_HYSTERESIS		0x68
+#define DMA_RING_HYSTERESIS_VAL		0xFFFFFFFF
+#define DMA_RING_STATE			0x6C
+#define DMA_RING_STATE_WR_BASE		0x70
+#define DMA_RING_NE_INT_MODE		0x017C
+#define DMA_RING_NE_INT_MODE_SET(m, v)	\
+	((m) = ((m) & ~BIT(31 - (v))) | BIT(31 - (v)))
+#define DMA_RING_NE_INT_MODE_RESET(m, v)	\
+	((m) &= (~BIT(31 - (v))))
+#define DMA_RING_CLKEN			0xC208
+#define DMA_RING_SRST			0xC200
+#define DMA_RING_MEM_RAM_SHUTDOWN	0xD070
+#define DMA_RING_BLK_MEM_RDY		0xD074
+#define DMA_RING_BLK_MEM_RDY_VAL	0xFFFFFFFF
+#define DMA_RING_DESC_CNT(v)		(((v) & 0x0001FFFE) >> 1)
+#define DMA_RING_ID_GET(owner, num)	(((owner) << 6) | (num))
+#define DMA_RING_DST_ID(v)		((1 << 10) | (v))
+#define DMA_RING_CMD_OFFSET		0x2C
+#define DMA_RING_CMD_BASE_OFFSET(v)	((v) << 6)
+#define DMA_RING_COHERENT_SET(m)	(((u32 *)(m))[2] |= BIT(4))
+#define DMA_RING_ADDRL_SET(m, v)	(((u32 *)(m))[2] |= (((v) >> 8) << 5))
+#define DMA_RING_ADDRH_SET(m, v)	(((u32 *)(m))[3] |= ((v) >> 35))
+#define DMA_RING_ACCEPTLERR_SET(m)	(((u32 *)(m))[3] |= BIT(19))
+#define DMA_RING_SIZE_SET(m, v)		(((u32 *)(m))[3] |= ((v) << 23))
+#define DMA_RING_RECOMBBUF_SET(m)	(((u32 *)(m))[3] |= BIT(27))
+#define DMA_RING_RECOMTIMEOUTL_SET(m)	(((u32 *)(m))[3] |= (0x7 << 28))
+#define DMA_RING_RECOMTIMEOUTH_SET(m)	(((u32 *)(m))[4] |= 0x3)
+#define DMA_RING_SELTHRSH_SET(m)	(((u32 *)(m))[4] |= BIT(3))
+#define DMA_RING_TYPE_SET(m, v)		(((u32 *)(m))[4] |= ((v) << 19))
+
+/* DMA device csr registers and bit definitions */
+#define DMA_IPBRR		0x0
+#define DMA_DEV_ID_RD(v)	((v) & 0x00000FFF)
+#define DMA_BUS_ID_RD(v)	(((v) >> 12) & 3)
+#define DMA_REV_NO_RD(v)	(((v) >> 14) & 3)
+#define DMA_GCR			0x10
+#define DMA_CH_SETUP(v)		((v) = ((v) & ~0x000FFFFF) | 0x000AAFFF)
+#define DMA_ENABLE(v)		((v) |= BIT(31))
+#define DMA_DISABLE(v)		((v) &= ~BIT(31))
+#define DMA_INT			0x70
+#define DMA_INT_MASK		0x74
+#define DMA_INT_ALL_MASK	0xFFFFFFFF
+#define DMA_INT_ALL_UNMASK	0x0
+#define DMA_INT_MASK_SHIFT	0x14
+#define DMA_RING_INT0_MASK	0x90A0
+#define DMA_RING_INT1_MASK	0x90A8
+#define DMA_RING_INT2_MASK	0x90B0
+#define DMA_RING_INT3_MASK	0x90B8
+#define DMA_RING_INT4_MASK	0x90C0
+#define DMA_CFG_RING_WQ_ASSOC	0x90E0
+#define DMA_ASSOC_RING_MNGR1	0xFFFFFFFF
+#define DMA_MEM_RAM_SHUTDOWN	0xD070
+#define DMA_BLK_MEM_RDY		0xD074
+#define DMA_BLK_MEM_RDY_VAL	0xFFFFFFFF
+
+/* DMA Descriptor format */
+#define DMA_DESC_ELERR_RD(m)		(((m) >> 46) & 0x3)
+#define DMA_DESC_NV_SET(m)		(((u64 *)(m))[0] |= BIT_ULL(50))
+#define DMA_DESC_IN_SET(m)		(((u64 *)(m))[0] |= BIT_ULL(55))
+#define DMA_DESC_RTYPE_SET(m, v)	(((u64 *)(m))[0] |= ((u64)(v) << 56))
+#define DMA_DESC_LERR_RD(m)		(((m) >> 60) & 0x7)
+#define DMA_DESC_BUFADDR_SET(m, v)	(((u64 *)(m))[0] |= (v))
+#define DMA_DESC_BUFLEN_SET(m, v)	(((u64 *)(m))[0] |= ((u64)(v) << 48))
+#define DMA_DESC_C_SET(m)		(((u64 *)(m))[1] |= BIT_ULL(63))
+#define DMA_DESC_DR_SET(m)		(((u64 *)(m))[2] |= BIT_ULL(61))
+#define DMA_DESC_DST_ADDR_SET(m, v)	(((u64 *)(m))[3] |= (v))
+#define DMA_DESC_H0ENQ_NUM_SET(m, v)	(((u64 *)(m))[3] |= ((u64)(v) << 48))
+#define DMA_DESC_STATUS(x, y)		(((x) << 4) | (y))
+
+/* DMA descriptor empty s/w signature */
+#define DMA_DESC_EMPTY_INDEX		0
+#define DMA_DESC_EMPTY_SIGNATURE	~0ULL
+#define DMA_DESC_SET_EMPTY(m)		\
+	(((u64 *)(m))[DMA_DESC_EMPTY_INDEX] = DMA_DESC_EMPTY_SIGNATURE)
+#define DMA_DESC_IS_EMPTY(m)		\
+	(((u64 *)(m))[DMA_DESC_EMPTY_INDEX] == DMA_DESC_EMPTY_SIGNATURE)
+
+/* DMA configurable parameters defines */
+#define DMA_RING_NUM			512
+#define DMA_BUFNUM			0x0
+#define DMA_CPU_BUFNUM			0x18
+#define DMA_RING_OWNER_DMA		0x03
+#define DMA_RING_OWNER_CPU		0x0F
+#define DMA_RING_TYPE_REGULAR		0x01
+#define DMA_RING_WQ_DESC_SIZE		32
+#define DMA_RING_NUM_CONFIG		5
+#define DMA_MAX_CHANNEL			4
+#define DMA_MAX_BYTE_CNT		0x4000	/* 16 KB */
+#define DMA_MAX_64B_DESC_BYTE_CNT	0x14000	/* 80 KB */
+#define DMA_16K_BUFFER_LEN_CODE		0x0
+#define DMA_INVALID_LEN_CODE		0x7800
+
+/* DMA descriptor error codes */
+#define ERR_DESC_AXI		0x01
+#define ERR_BAD_DESC		0x02
+#define ERR_READ_DATA_AXI	0x03
+#define ERR_WRITE_DATA_AXI	0x04
+#define ERR_FBP_TIMEOUT		0x05
+#define ERR_ECC			0x06
+#define ERR_DIFF_SIZE		0x08
+#define ERR_SCT_GAT_LEN		0x09
+#define ERR_CRC_ERR		0x11
+#define ERR_CHKSUM		0x12
+#define ERR_DIF			0x13
+
+/* DMA error interrupt codes */
+#define ERR_DIF_SIZE_INT	0x0
+#define ERR_GS_ERR_INT		0x1
+#define ERR_FPB_TIMEO_INT	0x2
+#define ERR_WFIFO_OVF_INT	0x3
+#define ERR_RFIFO_OVF_INT	0x4
+#define ERR_WR_TIMEO_INT	0x5
+#define ERR_RD_TIMEO_INT	0x6
+#define ERR_WR_ERR_INT		0x7
+#define ERR_RD_ERR_INT		0x8
+#define ERR_BAD_DESC_INT	0x9
+#define ERR_DESC_DST_INT	0xA
+#define ERR_DESC_SRC_INT	0xB
+
+/* Define to dump DMA descriptor */
+#define DMA_DESC_ERR_DUMP(desc)	\
+	print_hex_dump(KERN_ERR, "X-Gene DMA: Rx ERR DESC ",	\
+			DUMP_PREFIX_ADDRESS, 16, 8, (desc), 32, 0)
+
+#define to_dma_desc_sw(tx)	\
+	container_of(tx, struct xgene_dma_desc_sw, tx)
+#define to_dma_chan(dchan)	\
+	container_of(dchan, struct xgene_dma_chan, dma_chan)
+
+#define chan_dbg(chan, fmt, arg...)	\
+	dev_dbg(chan->dev, "%s: " fmt, chan->name, ##arg)
+#define chan_err(chan, fmt, arg...)	\
+	dev_err(chan->dev, "%s: " fmt, chan->name, ##arg)
+
+struct xgene_dma_desc_hw {
+	u64 m0;
+	u64 m1;
+	u64 m2;
+	u64 m3;
+};
+
+enum xgene_dma_ring_cfgsize {
+	DMA_RING_CFG_SIZE_512B,
+	DMA_RING_CFG_SIZE_2KB,
+	DMA_RING_CFG_SIZE_16KB,
+	DMA_RING_CFG_SIZE_64KB,
+	DMA_RING_CFG_SIZE_512KB,
+	DMA_RING_CFG_SIZE_INVALID
+};
+
+struct xgene_dma_ring {
+	struct xgene_dma *pdma;
+	u8 buf_num;
+	u16 id;
+	u16 num;
+	u16 head;
+	u16 owner;
+	u16 slots;
+	u16 dst_ring_num;
+	u32 size;
+	void __iomem *cmd;
+	void __iomem *cmd_base;
+	dma_addr_t desc_paddr;
+	u32 state[DMA_RING_NUM_CONFIG];
+	enum xgene_dma_ring_cfgsize cfgsize;
+	union {
+		void *desc_vaddr;
+		struct xgene_dma_desc_hw *desc_hw;
+	};
+};
+
+struct xgene_dma_desc_sw {
+	struct xgene_dma_desc_hw desc1;
+	struct xgene_dma_desc_hw desc2;
+	u8 desc_cnt;
+	struct list_head node;
+	struct list_head tx_list;
+	struct dma_async_tx_descriptor tx;
+};
+
+/**
+ * struct xgene_dma_chan - internal representation of an DMA channel
+ * @dma_chan: dmaengine channel object member
+ * @pdma: DMA device structure reference
+ * @dev: struct device reference for dma mapping api
+ * @id: raw id of this channel
+ * @rx_irq: channel IRQ
+ * @name: name of DMA channel
+ * @lock: serializes enqueue/dequeue operations to the descriptor pool
+ * @pending: number of transaction request pushed to DMA controller for
+ *	execution, but still waiting for completion,
+ * @ld_pending: descriptors which are queued to run, but have not yet been
+ *	submitted to the hardware for execution
+ * @ld_running: descriptors which are currently being executing by the hardware
+ * @ld_completed: descriptors which have finished execution by the hardware.
+ *	These descriptors have already had their cleanup actions run. They
+ *	are waiting for the ACK bit to be set by the async tx API.
+ * @desc_pool: descriptor pool for DMA operations
+ * @tasklet: bottom half where all completed descriptors cleans
+ * @tx_ring: transmit ring descriptor that we use to prepare actual
+ *	descriptors for further executions
+ * @rx_ring: receive ring descriptor that we use to get completed DMA
+ *	descriptors during cleanup time
+ */
+struct xgene_dma_chan {
+	struct dma_chan dma_chan;
+	struct xgene_dma *pdma;
+	struct device *dev;
+	int id;
+	int rx_irq;
+	char name[8];
+	spinlock_t lock;
+	int pending;
+	struct list_head ld_pending;
+	struct list_head ld_running;
+	struct list_head ld_completed;
+	struct dma_pool *desc_pool;
+	struct tasklet_struct tasklet;
+	struct xgene_dma_ring tx_ring;
+	struct xgene_dma_ring rx_ring;
+};
+
+/**
+ * struct xgene_dma - internal representation of an DMA device
+ * @err_irq: DMA error irq number
+ * @ring_num: start id number for DMA ring
+ * @csr_dma: base for DMA register access
+ * @csr_ring: base for DMA ring register access
+ * @csr_ring_cmd: base for DMA ring command register access
+ * @dma_dev: embedded struct dma_device
+ * @chan: reference to DMA channels
+ */
+struct xgene_dma {
+	struct device *dev;
+	struct clk *clk;
+	int err_irq;
+	int ring_num;
+	void __iomem *csr_dma;
+	void __iomem *csr_ring;
+	void __iomem *csr_ring_cmd;
+	struct dma_device dma_dev[DMA_MAX_CHANNEL];
+	struct xgene_dma_chan chan[DMA_MAX_CHANNEL];
+};
+
+static const char * const xgene_dma_desc_hw_err[] = {
+	[ERR_DESC_AXI] = "AXI error when reading src/dst link list",
+	[ERR_BAD_DESC] = "ERR or El_ERR fields not set to zero in desc",
+	[ERR_READ_DATA_AXI] = "AXI error when reading data",
+	[ERR_WRITE_DATA_AXI] = "AXI error when writing data",
+	[ERR_FBP_TIMEOUT] = "Timeout on bufpool fetch",
+	[ERR_ECC] = "ECC double bit error",
+	[ERR_DIFF_SIZE] = "Bufpool too small to hold all the DIF result",
+	[ERR_SCT_GAT_LEN] = "Gather and scatter data length not same",
+	[ERR_CRC_ERR] = "CRC error",
+	[ERR_CHKSUM] = "Checksum error",
+	[ERR_DIF] = "DIF error",
+};
+
+static const char * const xgene_dma_err[] = {
+	[ERR_DIF_SIZE_INT] = "DIF size error",
+	[ERR_GS_ERR_INT] = "Gather scatter not same size error",
+	[ERR_FPB_TIMEO_INT] = "Free pool time out error",
+	[ERR_WFIFO_OVF_INT] = "Write FIFO over flow error",
+	[ERR_RFIFO_OVF_INT] = "Read FIFO over flow error",
+	[ERR_WR_TIMEO_INT] = "Write time out error",
+	[ERR_RD_TIMEO_INT] = "Read time out error",
+	[ERR_WR_ERR_INT] = "HBF bus write error",
+	[ERR_RD_ERR_INT] = "HBF bus read error",
+	[ERR_BAD_DESC_INT] = "Ring descriptor HE0 not set error",
+	[ERR_DESC_DST_INT] = "HFB reading dst link address error",
+	[ERR_DESC_SRC_INT] = "HFB reading src link address error",
+};
+
+static void xgene_dma_cpu_to_le64(u64 *desc, int count)
+{
+	int i;
+
+	for (i = 0; i < count; i++)
+		desc[i] = cpu_to_le64(desc[i]);
+}
+
+static u16 xgene_dma_encode_len(u32 len)
+{
+	return (len < DMA_MAX_BYTE_CNT) ?
+		len : DMA_16K_BUFFER_LEN_CODE;
+}
+
+static u32 xgene_dma_ring_desc_cnt(struct xgene_dma_ring *ring)
+{
+	u32 __iomem *cmd_base = ring->cmd_base;
+	u32 ring_state = ioread32(&cmd_base[1]);
+
+	return DMA_RING_DESC_CNT(ring_state);
+}
+
+static void xgene_dma_set_src_buffer(void *ext8, size_t *len,
+				     dma_addr_t *paddr)
+{
+	size_t nbytes = (*len < DMA_MAX_BYTE_CNT) ?
+			*len : DMA_MAX_BYTE_CNT;
+
+	DMA_DESC_BUFADDR_SET(ext8, *paddr);
+	DMA_DESC_BUFLEN_SET(ext8, xgene_dma_encode_len(*len));
+	*len -= nbytes;
+	*paddr += nbytes;
+}
+
+static void xgene_dma_invalidate_buffer(void *ext8)
+{
+	DMA_DESC_BUFLEN_SET(ext8, DMA_INVALID_LEN_CODE);
+}
+
+static void *xgene_dma_lookup_ext8(u64 *desc, int idx)
+{
+	return (idx % 2) ? (desc + idx - 1) : (desc + idx + 1);
+}
+
+static void xgene_dma_init_desc(void *desc, u16 dst_ring_num)
+{
+	DMA_DESC_C_SET(desc); /* Coherent IO */
+	DMA_DESC_IN_SET(desc);
+	DMA_DESC_DR_SET(desc);
+	DMA_DESC_RTYPE_SET(desc, DMA_RING_OWNER_DMA);
+	DMA_DESC_H0ENQ_NUM_SET(desc, dst_ring_num);
+}
+
+static void xgene_dma_prep_cpy_desc(struct xgene_dma_chan *chan,
+				    struct xgene_dma_desc_sw *desc_sw,
+				    dma_addr_t dst, dma_addr_t src,
+				    size_t len)
+{
+	struct xgene_dma_ring *ring = &chan->tx_ring;
+	void *desc1, *desc2;
+	int i;
+
+	/* Get 1st descriptor */
+	desc1 = &desc_sw->desc1;
+	xgene_dma_init_desc(desc1, ring->dst_ring_num);
+	DMA_DESC_DST_ADDR_SET(desc1, dst);
+
+	/* Set 1st source address */
+	xgene_dma_set_src_buffer(desc1 + 8, &len, &src);
+
+	if (len <= 0) {
+		desc2 = NULL;
+		desc_sw->desc_cnt = 1;
+		goto skip_additional_src;
+	}
+
+	/*
+	 * We need to split this source buffer,
+	 * and need to use 2nd descriptor
+	 */
+	desc2 = &desc_sw->desc2;
+	DMA_DESC_NV_SET(desc1);
+
+	/* Set 2nd to 5th source address */
+	for (i = 0; i < 4 && len; i++)
+		xgene_dma_set_src_buffer(xgene_dma_lookup_ext8(desc2, i),
+					 &len, &src);
+
+	/* Invalidate unused source address field */
+	for (; i < 4; i++)
+		xgene_dma_invalidate_buffer(xgene_dma_lookup_ext8(desc2, i));
+
+	desc_sw->desc_cnt = 2;
+
+skip_additional_src:
+	/* Hardware stores descriptor in little endian format */
+	xgene_dma_cpu_to_le64(desc1, 4);
+	if (desc2)
+		xgene_dma_cpu_to_le64(desc2, 4);
+}
+
+static dma_cookie_t xgene_dma_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	struct xgene_dma_desc_sw *desc;
+	struct xgene_dma_chan *chan;
+	dma_cookie_t cookie;
+
+	if (unlikely(!tx))
+		return -EINVAL;
+
+	chan = to_dma_chan(tx->chan);
+	desc = to_dma_desc_sw(tx);
+
+	spin_lock_bh(&chan->lock);
+
+	cookie = dma_cookie_assign(tx);
+
+	/* Add this transaction list onto the tail of the pending queue */
+	list_splice_tail_init(&desc->tx_list, &chan->ld_pending);
+
+	spin_unlock_bh(&chan->lock);
+
+	return cookie;
+}
+
+static void xgene_dma_free_descriptor(struct xgene_dma_chan *chan,
+				      struct xgene_dma_desc_sw *desc)
+{
+	list_del(&desc->node);
+	chan_dbg(chan, "LD %p free\n", desc);
+	dma_pool_free(chan->desc_pool, desc, desc->tx.phys);
+}
+
+static struct xgene_dma_desc_sw *xgene_dma_alloc_descriptor(
+				 struct xgene_dma_chan *chan)
+{
+	struct xgene_dma_desc_sw *desc;
+	dma_addr_t phys;
+
+	desc = dma_pool_alloc(chan->desc_pool, GFP_NOWAIT, &phys);
+	if (!desc) {
+		chan_dbg(chan, "Failed to allocate LDs\n");
+		return NULL;
+	}
+
+	memset(desc, 0, sizeof(*desc));
+
+	INIT_LIST_HEAD(&desc->tx_list);
+	desc->tx.phys = phys;
+	desc->tx.tx_submit = xgene_dma_tx_submit;
+	dma_async_tx_descriptor_init(&desc->tx, &chan->dma_chan);
+
+	chan_dbg(chan, "LD %p allocated\n", desc);
+
+	return desc;
+}
+
+/**
+ * xgene_dma_clean_completed_descriptor - free all descriptors which
+ * has been completed and acked
+ * @chan: DMA channel
+ *
+ * This function is used on all completed and acked descriptors.
+ * All descriptors should only be freed in this function.
+ */
+static void xgene_dma_clean_completed_descriptor(struct xgene_dma_chan *chan)
+{
+	struct xgene_dma_desc_sw *desc, *_desc;
+
+	/* Run the callback for each descriptor, in order */
+	list_for_each_entry_safe(desc, _desc, &chan->ld_completed, node) {
+		if (async_tx_test_ack(&desc->tx))
+			xgene_dma_free_descriptor(chan, desc);
+	}
+}
+
+/**
+ * xgene_dma_run_tx_complete_actions - cleanup a single link descriptor
+ * @chan: DMA channel
+ * @desc: descriptor to cleanup and free
+ *
+ * This function is used on a descriptor which has been executed by the DMA
+ * controller. It will run any callbacks, submit any dependencies.
+ */
+static void xgene_dma_run_tx_complete_actions(struct xgene_dma_chan *chan,
+					      struct xgene_dma_desc_sw *desc)
+{
+	struct dma_async_tx_descriptor *tx = &desc->tx;
+
+	if (tx->cookie == 0)
+		return;
+
+	dma_cookie_complete(tx);
+
+	/* Run the link descriptor callback function */
+	if (tx->callback)
+		tx->callback(tx->callback_param);
+
+	dma_descriptor_unmap(tx);
+
+	/* Run any dependencies */
+	dma_run_dependencies(tx);
+}
+
+/**
+ * xgene_dma_clean_running_descriptor - move the completed descriptor from
+ * ld_running to ld_completed
+ * @chan: DMA channel
+ * @desc: the descriptor which is completed
+ *
+ * Free the descriptor directly if acked by async_tx api, or move it to
+ * queue ld_completed.
+ */
+static void xgene_dma_clean_running_descriptor(struct xgene_dma_chan *chan,
+					       struct xgene_dma_desc_sw *desc)
+{
+	/* Remove from the list of transactions */
+	list_del(&desc->node);
+
+	/*
+	 * the client is allowed to attach dependent operations
+	 * until 'ack' is set
+	 */
+	if (!async_tx_test_ack(&desc->tx)) {
+		/*
+		 * Move this descriptor to the list of descriptors which is
+		 * completed, but still awaiting the 'ack' bit to be set.
+		 */
+		list_add_tail(&desc->node, &chan->ld_completed);
+		return;
+	}
+
+	chan_dbg(chan, "LD %p free\n", desc);
+	dma_pool_free(chan->desc_pool, desc, desc->tx.phys);
+}
+
+/**
+ * xgene_chan_xfer_ld_pending - push any pending transactions to hw
+ * @chan : DMA channel
+ *
+ * LOCKING: must hold chan->desc_lock
+ */
+static void xgene_chan_xfer_ld_pending(struct xgene_dma_chan *chan)
+{
+	struct xgene_dma_ring *ring = &chan->tx_ring;
+	struct xgene_dma_desc_sw *desc_sw, *_desc_sw;
+	struct xgene_dma_desc_hw *desc_hw;
+
+	/*
+	 * If the list of pending descriptors is empty, then we
+	 * don't need to do any work at all
+	 */
+	if (list_empty(&chan->ld_pending)) {
+		chan_dbg(chan, "No pending LDs\n");
+		return;
+	}
+
+	/*
+	 * Move elements from the queue of pending transactions onto the list
+	 * of running transactions and push it to hw for further executions
+	 */
+
+	list_for_each_entry_safe(desc_sw, _desc_sw, &chan->ld_pending, node) {
+		/*
+		 * Check if have pushed max number of transactions to hw
+		 * as capable, so let's stop here and will push remaining
+		 * elements from pening ld queue after completing some
+		 * descriptors that we have already pushed
+		 */
+		if ((chan->pending >= ring->slots) ||
+		    (xgene_dma_ring_desc_cnt(ring) > (ring->slots - 2)))
+			break;
+
+		/* Get hw descriptor from DMA tx ring */
+		desc_hw = &ring->desc_hw[ring->head];
+
+		/*
+		 * Increment the head count to point next
+		 * descriptor for next time
+		 */
+		if (++ring->head == ring->slots)
+			ring->head = 0;
+
+		/* Copy prepared sw descriptor data to hw descriptor */
+		memcpy(desc_hw, &desc_sw->desc1, sizeof(*desc_hw));
+
+		/*
+		 * Check if we have prepared 64B descriptor,
+		 * in this case we need one more hw descriptor
+		 */
+		if (desc_sw->desc_cnt == 2) {
+			desc_hw = &ring->desc_hw[ring->head];
+
+			if (++ring->head == ring->slots)
+				ring->head = 0;
+
+			memcpy(desc_hw, &desc_sw->desc2, sizeof(*desc_hw));
+		}
+
+		/*
+		 * Delete this element from ld pending queue and append it to
+		 * ld running queue
+		 */
+		list_move_tail(&desc_sw->node, &chan->ld_running);
+
+		/* Increment the pending transaction count */
+		chan->pending++;
+
+		/* Notify the hw that we have descriptor ready for execution */
+		iowrite32(desc_sw->desc_cnt, ring->cmd);
+	}
+}
+
+/**
+ * xgene_dma_cleanup_descriptors - cleanup link descriptors which are completed
+ * and move them to ld_completed to free until flag 'ack' is set
+ * @chan: DMA channel
+ *
+ * This function is used on descriptors which have been executed by the DMA
+ * controller. It will run any callbacks, submit any dependencies, then
+ * free these descriptors if flag 'ack' is set.
+ */
+static void xgene_dma_cleanup_descriptors(struct xgene_dma_chan *chan)
+{
+	struct xgene_dma_ring *ring = &chan->rx_ring;
+	struct xgene_dma_desc_sw *desc_sw, *_desc_sw;
+	struct xgene_dma_desc_hw *desc_hw;
+	u8 status;
+
+	/* Clean already completed and acked descriptors */
+	xgene_dma_clean_completed_descriptor(chan);
+
+	/* Run the callback for each descriptor, in order */
+	list_for_each_entry_safe(desc_sw, _desc_sw, &chan->ld_running, node) {
+		/* Get subsequent hw descriptor from DMA rx ring */
+		desc_hw = &ring->desc_hw[ring->head];
+
+		/* Check if this descriptor has been completed */
+		if (unlikely(DMA_DESC_IS_EMPTY(desc_hw)))
+			break;
+
+		if (++ring->head == ring->slots)
+			ring->head = 0;
+
+		/* Check if we have any error with DMA transactions */
+		status = DMA_DESC_STATUS(
+				DMA_DESC_ELERR_RD(le64_to_cpu(desc_hw->m0)),
+				DMA_DESC_LERR_RD(le64_to_cpu(desc_hw->m0)));
+		if (status) {
+			chan_err(chan, "%s\n", xgene_dma_desc_hw_err[status]);
+			DMA_DESC_ERR_DUMP(desc_hw);
+		}
+
+		/* Notify the hw about this completed descriptor */
+		iowrite32(-1, ring->cmd);
+
+		/* Mark this hw descriptor as processed */
+		DMA_DESC_SET_EMPTY(desc_hw);
+
+		xgene_dma_run_tx_complete_actions(chan, desc_sw);
+
+		xgene_dma_clean_running_descriptor(chan, desc_sw);
+
+		/*
+		 * Decrement the pending transaction count
+		 * as we have processed one
+		 */
+		chan->pending--;
+	}
+
+	/*
+	 * Start any pending transactions automatically
+	 *
+	 * In the ideal case, we keep the DMA controller busy while we go
+	 * ahead and free the descriptors below.
+	 */
+	xgene_chan_xfer_ld_pending(chan);
+}
+
+static int xgene_dma_alloc_chan_resources(struct dma_chan *dchan)
+{
+	struct xgene_dma_chan *chan = to_dma_chan(dchan);
+
+	/* Has this channel already been allocated? */
+	if (chan->desc_pool)
+		return 1;
+
+	chan->desc_pool = dma_pool_create(chan->name, chan->dev,
+					  sizeof(struct xgene_dma_desc_sw),
+					  0, 0);
+	if (!chan->desc_pool) {
+		chan_err(chan, "Failed to allocate descriptor pool\n");
+		return -ENOMEM;
+	}
+
+	chan_dbg(chan, "Allocate descripto pool\n");
+
+	return 1;
+}
+
+/**
+ * xgene_dma_free_desc_list - Free all descriptors in a queue
+ * @chan: DMA channel
+ * @list: the list to free
+ *
+ * LOCKING: must hold chan->desc_lock
+ */
+static void xgene_dma_free_desc_list(struct xgene_dma_chan *chan,
+				     struct list_head *list)
+{
+	struct xgene_dma_desc_sw *desc, *_desc;
+
+	list_for_each_entry_safe(desc, _desc, list, node)
+		xgene_dma_free_descriptor(chan, desc);
+}
+
+static void xgene_dma_free_desc_list_reverse(struct xgene_dma_chan *chan,
+					     struct list_head *list)
+{
+	struct xgene_dma_desc_sw *desc, *_desc;
+
+	list_for_each_entry_safe_reverse(desc, _desc, list, node)
+		xgene_dma_free_descriptor(chan, desc);
+}
+
+static void xgene_dma_free_chan_resources(struct dma_chan *dchan)
+{
+	struct xgene_dma_chan *chan = to_dma_chan(dchan);
+
+	chan_dbg(chan, "Free all resources\n");
+
+	if (!chan->desc_pool)
+		return;
+
+	spin_lock_bh(&chan->lock);
+
+	/* Process all running descriptor */
+	xgene_dma_cleanup_descriptors(chan);
+
+	/* Clean all link descriptor queues */
+	xgene_dma_free_desc_list(chan, &chan->ld_pending);
+	xgene_dma_free_desc_list(chan, &chan->ld_running);
+	xgene_dma_free_desc_list(chan, &chan->ld_completed);
+
+	/* Delete this channel DMA pool */
+	dma_pool_destroy(chan->desc_pool);
+	chan->desc_pool = NULL;
+
+	spin_unlock_bh(&chan->lock);
+}
+
+static struct dma_async_tx_descriptor *xgene_dma_prep_memcpy(
+	struct dma_chan *dchan, dma_addr_t dst, dma_addr_t src,
+	size_t len, unsigned long flags)
+{
+	struct xgene_dma_desc_sw *first = NULL, *new;
+	struct xgene_dma_chan *chan;
+	size_t copy;
+
+	if (unlikely(!dchan || (len == 0)))
+		return NULL;
+
+	chan = to_dma_chan(dchan);
+
+	do {
+		/* Allocate the link descriptor from DMA pool */
+		new = xgene_dma_alloc_descriptor(chan);
+		if (!new)
+			goto fail;
+
+		/* Create the largest transaction possible */
+		copy = min_t(size_t, len, DMA_MAX_64B_DESC_BYTE_CNT);
+
+		/* Prepare DMA descriptor */
+		xgene_dma_prep_cpy_desc(chan, new, dst, src, copy);
+
+		if (!first)
+			first = new;
+
+		new->tx.cookie = 0;
+		async_tx_ack(&new->tx);
+
+		/* Update metadata */
+		len -= copy;
+		dst += copy;
+		src += copy;
+
+		/* Insert the link descriptor to the LD ring */
+		list_add_tail(&new->node, &first->tx_list);
+	} while (len);
+
+	new->tx.flags = flags; /* client is in control of this ack */
+	new->tx.cookie = -EBUSY;
+	list_splice(&first->tx_list, &new->tx_list);
+
+	return &new->tx;
+
+fail:
+	if (!first)
+		return NULL;
+
+	xgene_dma_free_desc_list_reverse(chan, &first->tx_list);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *xgene_dma_prep_sg(
+	struct dma_chan *dchan, struct scatterlist *dst_sg,
+	unsigned int dst_nents, struct scatterlist *src_sg,
+	unsigned int src_nents, unsigned long flags)
+{
+	struct xgene_dma_desc_sw *first = NULL, *new = NULL;
+	struct xgene_dma_chan *chan;
+	size_t dst_avail, src_avail;
+	dma_addr_t dst, src;
+	size_t len;
+
+	if (unlikely(!dchan))
+		return NULL;
+
+	if (unlikely(dst_nents == 0 || src_nents == 0))
+		return NULL;
+
+	if (unlikely(!dst_sg || !src_sg))
+		return NULL;
+
+	chan = to_dma_chan(dchan);
+
+	/* Get prepared for the loop */
+	dst_avail = sg_dma_len(dst_sg);
+	src_avail = sg_dma_len(src_sg);
+	dst_nents--;
+	src_nents--;
+
+	/* Run until we are out of scatterlist entries */
+	while (true) {
+		/* Create the largest transaction possible */
+		len = min_t(size_t, src_avail, dst_avail);
+		len = min_t(size_t, len, DMA_MAX_64B_DESC_BYTE_CNT);
+		if (len == 0)
+			goto fetch;
+
+		dst = sg_dma_address(dst_sg) + sg_dma_len(dst_sg) - dst_avail;
+		src = sg_dma_address(src_sg) + sg_dma_len(src_sg) - src_avail;
+
+		/* Allocate the link descriptor from DMA pool */
+		new = xgene_dma_alloc_descriptor(chan);
+		if (!new)
+			goto fail;
+
+		/* Prepare DMA descriptor */
+		xgene_dma_prep_cpy_desc(chan, new, dst, src, len);
+
+		if (!first)
+			first = new;
+
+		new->tx.cookie = 0;
+		async_tx_ack(&new->tx);
+
+		/* update metadata */
+		dst_avail -= len;
+		src_avail -= len;
+
+		/* Insert the link descriptor to the LD ring */
+		list_add_tail(&new->node, &first->tx_list);
+
+fetch:
+		/* fetch the next dst scatterlist entry */
+		if (dst_avail == 0) {
+			/* no more entries: we're done */
+			if (dst_nents == 0)
+				break;
+
+			/* fetch the next entry: if there are no more: done */
+			dst_sg = sg_next(dst_sg);
+			if (!dst_sg)
+				break;
+
+			dst_nents--;
+			dst_avail = sg_dma_len(dst_sg);
+		}
+
+		/* fetch the next src scatterlist entry */
+		if (src_avail == 0) {
+			/* no more entries: we're done */
+			if (src_nents == 0)
+				break;
+
+			/* fetch the next entry: if there are no more: done */
+			src_sg = sg_next(src_sg);
+			if (!src_sg)
+				break;
+
+			src_nents--;
+			src_avail = sg_dma_len(src_sg);
+		}
+	}
+
+	if (!new)
+		return NULL;
+
+	new->tx.flags = flags; /* client is in control of this ack */
+	new->tx.cookie = -EBUSY;
+	list_splice(&first->tx_list, &new->tx_list);
+
+	return &new->tx;
+
+fail:
+	if (!first)
+		return NULL;
+
+	xgene_dma_free_desc_list_reverse(chan, &first->tx_list);
+	return NULL;
+}
+
+static void xgene_dma_issue_pending(struct dma_chan *dchan)
+{
+	struct xgene_dma_chan *chan = to_dma_chan(dchan);
+
+	spin_lock_bh(&chan->lock);
+	xgene_chan_xfer_ld_pending(chan);
+	spin_unlock_bh(&chan->lock);
+}
+
+static enum dma_status xgene_dma_tx_status(struct dma_chan *dchan,
+					   dma_cookie_t cookie,
+					   struct dma_tx_state *txstate)
+{
+	struct xgene_dma_chan *chan = to_dma_chan(dchan);
+	enum dma_status status;
+
+	status = dma_cookie_status(dchan, cookie, txstate);
+	if (status == DMA_COMPLETE)
+		return status;
+
+	/* Cleanup any running and executed descriptors */
+	spin_lock_bh(&chan->lock);
+	xgene_dma_cleanup_descriptors(chan);
+	spin_unlock_bh(&chan->lock);
+
+	return dma_cookie_status(dchan, cookie, txstate);
+}
+
+static void xgene_dma_tasklet_cb(unsigned long data)
+{
+	struct xgene_dma_chan *chan = (struct xgene_dma_chan *)data;
+
+	spin_lock_bh(&chan->lock);
+
+	/* Run all cleanup for descriptors which have been completed */
+	xgene_dma_cleanup_descriptors(chan);
+
+	/* Re-enable DMA channel IRQ */
+	enable_irq(chan->rx_irq);
+
+	spin_unlock_bh(&chan->lock);
+}
+
+static irqreturn_t xgene_dma_chan_ring_isr(int irq, void *id)
+{
+	struct xgene_dma_chan *chan = (struct xgene_dma_chan *)id;
+
+	BUG_ON(!chan);
+
+	/*
+	 * Disable DMA channel IRQ until we process completed
+	 * descriptors
+	 */
+	disable_irq_nosync(chan->rx_irq);
+
+	/*
+	 * Schedule the tasklet to handle all cleanup of the current
+	 * transaction. It will start a new transaction if there is
+	 * one pending.
+	 */
+	tasklet_schedule(&chan->tasklet);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t xgene_dma_err_isr(int irq, void *id)
+{
+	struct xgene_dma *pdma = (struct xgene_dma *)id;
+	unsigned long int_mask;
+	u32 val, i;
+
+	val = ioread32(pdma->csr_dma + DMA_INT);
+
+	/* Clear DMA interrupts */
+	iowrite32(val, pdma->csr_dma + DMA_INT);
+
+	/* Print DMA error info */
+	int_mask = val >> DMA_INT_MASK_SHIFT;
+	for_each_set_bit(i, &int_mask, ARRAY_SIZE(xgene_dma_err))
+		dev_err(pdma->dev,
+			"Interrupt status 0x%08X %s\n", val, xgene_dma_err[i]);
+
+	return IRQ_HANDLED;
+}
+
+static void xgene_dma_wr_ring_state(struct xgene_dma_ring *ring)
+{
+	int i;
+
+	iowrite32(ring->num, ring->pdma->csr_ring + DMA_RING_STATE);
+
+	for (i = 0; i < DMA_RING_NUM_CONFIG; i++)
+		iowrite32(ring->state[i], ring->pdma->csr_ring +
+			  DMA_RING_STATE_WR_BASE + (i * 4));
+}
+
+static void xgene_dma_clr_ring_state(struct xgene_dma_ring *ring)
+{
+	memset(ring->state, 0, sizeof(u32) * DMA_RING_NUM_CONFIG);
+	xgene_dma_wr_ring_state(ring);
+}
+
+static void xgene_dma_setup_ring(struct xgene_dma_ring *ring)
+{
+	void *ring_cfg = ring->state;
+	u64 addr = ring->desc_paddr;
+	void *desc;
+	u32 i, val;
+
+	ring->slots = ring->size / DMA_RING_WQ_DESC_SIZE;
+
+	/* Clear DMA ring state */
+	xgene_dma_clr_ring_state(ring);
+
+	/* Set DMA ring type */
+	DMA_RING_TYPE_SET(ring_cfg, DMA_RING_TYPE_REGULAR);
+
+	if (ring->owner == DMA_RING_OWNER_DMA) {
+		/* Set recombination buffer and timeout */
+		DMA_RING_RECOMBBUF_SET(ring_cfg);
+		DMA_RING_RECOMTIMEOUTL_SET(ring_cfg);
+		DMA_RING_RECOMTIMEOUTH_SET(ring_cfg);
+	}
+
+	/* Initialize DMA ring state */
+	DMA_RING_SELTHRSH_SET(ring_cfg);
+	DMA_RING_ACCEPTLERR_SET(ring_cfg);
+	DMA_RING_COHERENT_SET(ring_cfg);
+	DMA_RING_ADDRL_SET(ring_cfg, addr);
+	DMA_RING_ADDRH_SET(ring_cfg, addr);
+	DMA_RING_SIZE_SET(ring_cfg, ring->cfgsize);
+
+	/* Write DMA ring configurations */
+	xgene_dma_wr_ring_state(ring);
+
+	/* Set DMA ring id */
+	iowrite32(DMA_RING_ID_SETUP(ring->id),
+		  ring->pdma->csr_ring + DMA_RING_ID);
+
+	/* Set DMA ring buffer */
+	iowrite32(DMA_RING_ID_BUF_SETUP(ring->num),
+		  ring->pdma->csr_ring + DMA_RING_ID_BUF);
+
+	if (ring->owner != DMA_RING_OWNER_CPU)
+		return;
+
+	/* Set empty signature to DMA Rx ring descriptors */
+	for (i = 0; i < ring->slots; i++) {
+		desc = &ring->desc_hw[i];
+		DMA_DESC_SET_EMPTY(desc);
+	}
+
+	/* Enable DMA Rx ring interrupt */
+	val = ioread32(ring->pdma->csr_ring + DMA_RING_NE_INT_MODE);
+	DMA_RING_NE_INT_MODE_SET(val, ring->buf_num);
+	iowrite32(val, ring->pdma->csr_ring + DMA_RING_NE_INT_MODE);
+}
+
+static void xgene_dma_clear_ring(struct xgene_dma_ring *ring)
+{
+	u32 ring_id, val;
+
+	if (ring->owner == DMA_RING_OWNER_CPU) {
+		/* Disable DMA Rx ring interrupt */
+		val = ioread32(ring->pdma->csr_ring + DMA_RING_NE_INT_MODE);
+		DMA_RING_NE_INT_MODE_RESET(val, ring->buf_num);
+		iowrite32(val, ring->pdma->csr_ring + DMA_RING_NE_INT_MODE);
+	}
+
+	/* Clear DMA ring state */
+	ring_id = DMA_RING_ID_SETUP(ring->id);
+	iowrite32(ring_id, ring->pdma->csr_ring + DMA_RING_ID);
+
+	iowrite32(0, ring->pdma->csr_ring + DMA_RING_ID_BUF);
+	xgene_dma_clr_ring_state(ring);
+}
+
+static void xgene_dma_set_ring_cmd(struct xgene_dma_ring *ring)
+{
+	ring->cmd_base = ring->pdma->csr_ring_cmd +
+			DMA_RING_CMD_BASE_OFFSET((ring->num - DMA_RING_NUM));
+	ring->cmd = ring->cmd_base + DMA_RING_CMD_OFFSET;
+}
+
+static int xgene_dma_get_ring_size(struct xgene_dma_chan *chan,
+				   enum xgene_dma_ring_cfgsize cfgsize)
+{
+	int size;
+
+	switch (cfgsize) {
+	case DMA_RING_CFG_SIZE_512B:
+		size = 0x200;
+		break;
+	case DMA_RING_CFG_SIZE_2KB:
+		size = 0x800;
+		break;
+	case DMA_RING_CFG_SIZE_16KB:
+		size = 0x4000;
+		break;
+	case DMA_RING_CFG_SIZE_64KB:
+		size = 0x10000;
+		break;
+	case DMA_RING_CFG_SIZE_512KB:
+		size = 0x80000;
+		break;
+	default:
+		chan_err(chan, "Unsupported cfg ring size %d\n", cfgsize);
+		return -EINVAL;
+	}
+
+	return size;
+}
+
+static void xgene_dma_delete_ring_one(struct xgene_dma_ring *ring)
+{
+	/* Clear DMA ring configurations */
+	xgene_dma_clear_ring(ring);
+
+	/* De-allocate DMA ring descriptor */
+	if (ring->desc_vaddr) {
+		dma_free_coherent(ring->pdma->dev, ring->size,
+				  ring->desc_vaddr, ring->desc_paddr);
+		ring->desc_vaddr = NULL;
+	}
+}
+
+static void xgene_dma_delete_chan_rings(struct xgene_dma_chan *chan)
+{
+	xgene_dma_delete_ring_one(&chan->rx_ring);
+	xgene_dma_delete_ring_one(&chan->tx_ring);
+}
+
+static int xgene_dma_create_ring_one(struct xgene_dma_chan *chan,
+				     struct xgene_dma_ring *ring,
+				     enum xgene_dma_ring_cfgsize cfgsize)
+{
+	/* Setup DMA ring descriptor variables */
+	ring->pdma = chan->pdma;
+	ring->cfgsize = cfgsize;
+	ring->num = chan->pdma->ring_num++;
+	ring->id = DMA_RING_ID_GET(ring->owner, ring->buf_num);
+
+	ring->size = xgene_dma_get_ring_size(chan, cfgsize);
+	if (ring->size <= 0)
+		return ring->size;
+
+	/* Allocate memory for DMA ring descriptor */
+	ring->desc_vaddr = dma_zalloc_coherent(chan->dev, ring->size,
+					       &ring->desc_paddr, GFP_KERNEL);
+	if (!ring->desc_vaddr) {
+		chan_err(chan, "Failed to allocate ring desc\n");
+		return -ENOMEM;
+	}
+
+	/* Configure and enable DMA ring */
+	xgene_dma_set_ring_cmd(ring);
+	xgene_dma_setup_ring(ring);
+
+	return 0;
+}
+
+static int xgene_dma_create_chan_rings(struct xgene_dma_chan *chan)
+{
+	struct xgene_dma_ring *rx_ring = &chan->rx_ring;
+	struct xgene_dma_ring *tx_ring = &chan->tx_ring;
+	int ret;
+
+	/* Create DMA Rx ring descriptor */
+	rx_ring->owner = DMA_RING_OWNER_CPU;
+	rx_ring->buf_num = DMA_CPU_BUFNUM + chan->id;
+
+	ret = xgene_dma_create_ring_one(chan, rx_ring, DMA_RING_CFG_SIZE_64KB);
+	if (ret)
+		return ret;
+
+	chan_dbg(chan, "Rx ring id 0x%X num %d desc 0x%p\n",
+		 rx_ring->id, rx_ring->num, rx_ring->desc_vaddr);
+
+	/* Create DMA Tx ring descriptor */
+	tx_ring->owner = DMA_RING_OWNER_DMA;
+	tx_ring->buf_num = DMA_BUFNUM + chan->id;
+
+	ret = xgene_dma_create_ring_one(chan, tx_ring, DMA_RING_CFG_SIZE_64KB);
+	if (ret) {
+		xgene_dma_delete_ring_one(rx_ring);
+		return ret;
+	}
+
+	tx_ring->dst_ring_num = DMA_RING_DST_ID(rx_ring->num);
+
+	chan_dbg(chan,
+		 "Tx ring id 0x%X num %d desc 0x%p\n",
+		 tx_ring->id, tx_ring->num, tx_ring->desc_vaddr);
+
+	return ret;
+}
+
+static int xgene_dma_init_rings(struct xgene_dma *pdma)
+{
+	int ret, i, j;
+
+	for (i = 0; i < DMA_MAX_CHANNEL; i++) {
+		ret = xgene_dma_create_chan_rings(&pdma->chan[i]);
+		if (ret) {
+			for (j = 0; j < i; j++)
+				xgene_dma_delete_chan_rings(&pdma->chan[j]);
+			return ret;
+		}
+	}
+
+	return ret;
+}
+
+static void xgene_dma_enable(struct xgene_dma *pdma)
+{
+	u32 val;
+
+	/* Configure and enable DMA engine */
+	val = ioread32(pdma->csr_dma + DMA_GCR);
+	DMA_CH_SETUP(val);
+	DMA_ENABLE(val);
+	iowrite32(val, pdma->csr_dma + DMA_GCR);
+}
+
+static void xgene_dma_disable(struct xgene_dma *pdma)
+{
+	u32 val;
+
+	val = ioread32(pdma->csr_dma + DMA_GCR);
+	DMA_DISABLE(val);
+	iowrite32(val, pdma->csr_dma + DMA_GCR);
+}
+
+static void xgene_dma_mask_interrupts(struct xgene_dma *pdma)
+{
+	/*
+	 * Mask DMA ring overflow, underflow and
+	 * AXI write/read error interrupts
+	 */
+	iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_RING_INT0_MASK);
+	iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_RING_INT1_MASK);
+	iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_RING_INT2_MASK);
+	iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_RING_INT3_MASK);
+	iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_RING_INT4_MASK);
+
+	/* Mask DMA error interrupts */
+	iowrite32(DMA_INT_ALL_MASK, pdma->csr_dma + DMA_INT_MASK);
+}
+
+static void xgene_dma_unmask_interrupts(struct xgene_dma *pdma)
+{
+	/*
+	 * Unmask DMA ring overflow, underflow and
+	 * AXI write/read error interrupts
+	 */
+	iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_RING_INT0_MASK);
+	iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_RING_INT1_MASK);
+	iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_RING_INT2_MASK);
+	iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_RING_INT3_MASK);
+	iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_RING_INT4_MASK);
+
+	/* Unmask DMA error interrupts */
+	iowrite32(DMA_INT_ALL_UNMASK, pdma->csr_dma + DMA_INT_MASK);
+}
+
+static void xgene_dma_init_hw(struct xgene_dma *pdma)
+{
+	u32 val;
+
+	/* Associate DMA ring to corresponding ring HW */
+	iowrite32(DMA_ASSOC_RING_MNGR1,
+		  pdma->csr_dma + DMA_CFG_RING_WQ_ASSOC);
+
+	xgene_dma_enable(pdma);
+	xgene_dma_unmask_interrupts(pdma);
+
+	/* Get DMA id and version info */
+	val = ioread32(pdma->csr_dma + DMA_IPBRR);
+
+	/* DMA device info */
+	dev_info(pdma->dev,
+		 "X-Gene DMA v%d.%02d.%02d driver registered %d channels",
+		 DMA_REV_NO_RD(val), DMA_BUS_ID_RD(val),
+		 DMA_DEV_ID_RD(val), DMA_MAX_CHANNEL);
+}
+
+int xgene_dma_init_ring_mngr(struct xgene_dma *pdma)
+{
+	if (ioread32(pdma->csr_ring + DMA_RING_CLKEN) &&
+	    (!ioread32(pdma->csr_ring + DMA_RING_SRST)))
+		return 0;
+
+	iowrite32(0x3, pdma->csr_ring + DMA_RING_CLKEN);
+	iowrite32(0x0, pdma->csr_ring + DMA_RING_SRST);
+
+	/* Bring up memory */
+	iowrite32(0x0, pdma->csr_ring + DMA_RING_MEM_RAM_SHUTDOWN);
+
+	/* Force a barrier */
+	ioread32(pdma->csr_ring + DMA_RING_MEM_RAM_SHUTDOWN);
+
+	/* reset may take up to 1ms */
+	usleep_range(1000, 1100);
+
+	if (ioread32(pdma->csr_ring + DMA_RING_BLK_MEM_RDY)
+		!= DMA_RING_BLK_MEM_RDY_VAL) {
+		dev_err(pdma->dev,
+			"Failed to release ring mngr memory from shutdown\n");
+		return -ENODEV;
+	}
+
+	/* program threshold set 1 and all hysteresis */
+	iowrite32(DMA_RING_THRESLD0_SET1_VAL,
+		  pdma->csr_ring + DMA_RING_THRESLD0_SET1);
+	iowrite32(DMA_RING_THRESLD1_SET1_VAL,
+		  pdma->csr_ring + DMA_RING_THRESLD1_SET1);
+	iowrite32(DMA_RING_HYSTERESIS_VAL,
+		  pdma->csr_ring + DMA_RING_HYSTERESIS);
+
+	/* Enable QPcore and assign error queue */
+	iowrite32(DMA_RING_ENABLE, pdma->csr_ring + DMA_RING_CONFIG);
+
+	return 0;
+}
+
+static int xgene_dma_init_mem(struct xgene_dma *pdma)
+{
+	int ret;
+
+	ret = xgene_dma_init_ring_mngr(pdma);
+	if (ret)
+		return ret;
+
+	/* Bring up memory */
+	iowrite32(0x0, pdma->csr_dma + DMA_MEM_RAM_SHUTDOWN);
+
+	/* Force a barrier */
+	ioread32(pdma->csr_dma + DMA_MEM_RAM_SHUTDOWN);
+
+	/* reset may take up to 1ms */
+	usleep_range(1000, 1100);
+
+	if (ioread32(pdma->csr_dma + DMA_BLK_MEM_RDY)
+		!= DMA_BLK_MEM_RDY_VAL) {
+		dev_err(pdma->dev,
+			"Failed to release DMA memory from shutdown\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int xgene_dma_request_irqs(struct xgene_dma *pdma)
+{
+	struct xgene_dma_chan *chan;
+	int ret, i, j;
+
+	/* Register DMA error irq */
+	ret = devm_request_irq(pdma->dev, pdma->err_irq, xgene_dma_err_isr,
+			       0, "dma_error", pdma);
+	if (ret) {
+		dev_err(pdma->dev,
+			"Failed to register error IRQ %d\n", pdma->err_irq);
+		return ret;
+	}
+
+	/* Register DMA channel rx irq */
+	for (i = 0; i < DMA_MAX_CHANNEL; i++) {
+		chan = &pdma->chan[i];
+		ret = devm_request_irq(chan->dev, chan->rx_irq,
+				       xgene_dma_chan_ring_isr,
+				       0, chan->name, chan);
+		if (ret) {
+			chan_err(chan, "Failed to register Rx IRQ %d\n",
+				 chan->rx_irq);
+			devm_free_irq(pdma->dev, pdma->err_irq, pdma);
+
+			for (j = 0; j < i; j++) {
+				chan = &pdma->chan[i];
+				devm_free_irq(chan->dev, chan->rx_irq, chan);
+			}
+
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static void xgene_dma_free_irqs(struct xgene_dma *pdma)
+{
+	struct xgene_dma_chan *chan;
+	int i;
+
+	/* Free DMA device error irq */
+	devm_free_irq(pdma->dev, pdma->err_irq, pdma);
+
+	for (i = 0; i < DMA_MAX_CHANNEL; i++) {
+		chan = &pdma->chan[i];
+		devm_free_irq(chan->dev, chan->rx_irq, chan);
+	}
+}
+
+static void xgene_dma_set_caps(struct xgene_dma_chan *chan,
+			       struct dma_device *dma_dev)
+{
+	/* Initialize DMA device capability mask */
+	dma_cap_zero(dma_dev->cap_mask);
+
+	/* Set DMA device capability */
+	dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
+	dma_cap_set(DMA_SG, dma_dev->cap_mask);
+
+	/* Set base and prep routines */
+	dma_dev->dev = chan->dev;
+	dma_dev->device_alloc_chan_resources = xgene_dma_alloc_chan_resources;
+	dma_dev->device_free_chan_resources = xgene_dma_free_chan_resources;
+	dma_dev->device_issue_pending = xgene_dma_issue_pending;
+	dma_dev->device_tx_status = xgene_dma_tx_status;
+	dma_dev->device_prep_dma_memcpy = xgene_dma_prep_memcpy;
+	dma_dev->device_prep_dma_sg = xgene_dma_prep_sg;
+}
+
+static int xgene_dma_async_register(struct xgene_dma *pdma, int id)
+{
+	struct xgene_dma_chan *chan = &pdma->chan[id];
+	struct dma_device *dma_dev = &pdma->dma_dev[id];
+	int ret;
+
+	chan->dma_chan.device = dma_dev;
+
+	spin_lock_init(&chan->lock);
+	INIT_LIST_HEAD(&chan->ld_pending);
+	INIT_LIST_HEAD(&chan->ld_running);
+	INIT_LIST_HEAD(&chan->ld_completed);
+	tasklet_init(&chan->tasklet, xgene_dma_tasklet_cb,
+		     (unsigned long)chan);
+
+	chan->pending = 0;
+	chan->desc_pool = NULL;
+	dma_cookie_init(&chan->dma_chan);
+
+	/* Setup dma device capabilities and prep routines */
+	xgene_dma_set_caps(chan, dma_dev);
+
+	/* Initialize DMA device list head */
+	INIT_LIST_HEAD(&dma_dev->channels);
+	list_add_tail(&chan->dma_chan.device_node, &dma_dev->channels);
+
+	/* Register with Linux async DMA framework*/
+	ret = dma_async_device_register(dma_dev);
+	if (ret) {
+		chan_err(chan, "Failed to register async device %d", ret);
+		tasklet_kill(&chan->tasklet);
+
+		return ret;
+	}
+
+	/* DMA capability info */
+	dev_info(pdma->dev,
+		 "%s: CAPABILITY ( %s%s)\n", dma_chan_name(&chan->dma_chan),
+		 dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask) ? "MEMCPY " : "",
+		 dma_has_cap(DMA_SG, dma_dev->cap_mask) ? "SGCPY " : "");
+
+	return 0;
+}
+
+static int xgene_dma_init_async(struct xgene_dma *pdma)
+{
+	int ret, i, j;
+
+	for (i = 0; i < DMA_MAX_CHANNEL ; i++) {
+		ret = xgene_dma_async_register(pdma, i);
+		if (ret) {
+			for (j = 0; j < i; j++) {
+				dma_async_device_unregister(&pdma->dma_dev[j]);
+				tasklet_kill(&pdma->chan[j].tasklet);
+			}
+
+			return ret;
+		}
+	}
+
+	return ret;
+}
+
+static void xgene_dma_async_unregister(struct xgene_dma *pdma)
+{
+	int i;
+
+	for (i = 0; i < DMA_MAX_CHANNEL; i++)
+		dma_async_device_unregister(&pdma->dma_dev[i]);
+}
+
+static void xgene_dma_init_channels(struct xgene_dma *pdma)
+{
+	struct xgene_dma_chan *chan;
+	int i;
+
+	pdma->ring_num = DMA_RING_NUM;
+
+	for (i = 0; i < DMA_MAX_CHANNEL; i++) {
+		chan = &pdma->chan[i];
+		chan->dev = pdma->dev;
+		chan->pdma = pdma;
+		chan->id = i;
+		sprintf(chan->name, "chan%d", chan->id);
+	}
+}
+
+static int xgene_dma_get_resources(struct platform_device *pdev,
+				   struct xgene_dma *pdma)
+{
+	struct resource *res;
+	int irq, i;
+
+	/* Get DMA csr region */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dma_csr");
+	if (!res) {
+		dev_err(&pdev->dev, "Failed to get csr region\n");
+		return -ENXIO;
+	}
+
+	pdma->csr_dma = devm_ioremap(&pdev->dev, res->start,
+				     resource_size(res));
+	if (IS_ERR(pdma->csr_dma)) {
+		dev_err(&pdev->dev, "Failed to ioremap csr region");
+		return PTR_ERR(pdma->csr_dma);
+	}
+
+	/* Get DMA ring csr region */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ring_csr");
+	if (!res) {
+		dev_err(&pdev->dev, "Failed to get ring csr region\n");
+		return -ENXIO;
+	}
+
+	pdma->csr_ring =  devm_ioremap(&pdev->dev, res->start,
+				       resource_size(res));
+	if (IS_ERR(pdma->csr_ring)) {
+		dev_err(&pdev->dev, "Failed to ioremap ring csr region");
+		return PTR_ERR(pdma->csr_ring);
+	}
+
+	/* Get DMA ring cmd csr region */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+					   "ring_cmd_csr");
+	if (!res) {
+		dev_err(&pdev->dev, "Failed to get ring cmd csr region\n");
+		return -ENXIO;
+	}
+
+	pdma->csr_ring_cmd = devm_ioremap(&pdev->dev, res->start,
+					  resource_size(res));
+	if (IS_ERR(pdma->csr_ring_cmd)) {
+		dev_err(&pdev->dev, "Failed to ioremap ring cmd csr region");
+		return PTR_ERR(pdma->csr_ring_cmd);
+	}
+
+	/* Get DMA error interrupt */
+	irq = platform_get_irq(pdev, 0);
+	if (irq <= 0) {
+		dev_err(&pdev->dev, "Failed to get Error IRQ\n");
+		return -ENXIO;
+	}
+
+	pdma->err_irq = irq;
+
+	/* Get DMA Rx ring descriptor interrupts for all DMA channels */
+	for (i = 1; i <= DMA_MAX_CHANNEL; i++) {
+		irq = platform_get_irq(pdev, i);
+		if (irq <= 0) {
+			dev_err(&pdev->dev, "Failed to get Rx IRQ\n");
+			return -ENXIO;
+		}
+
+		pdma->chan[i - 1].rx_irq = irq;
+	}
+
+	return 0;
+}
+
+static int xgene_dma_probe(struct platform_device *pdev)
+{
+	struct xgene_dma *pdma;
+	int ret, i;
+
+	pdma = devm_kzalloc(&pdev->dev, sizeof(*pdma), GFP_KERNEL);
+	if (!pdma)
+		return -ENOMEM;
+
+	pdma->dev = &pdev->dev;
+	platform_set_drvdata(pdev, pdma);
+
+	ret = xgene_dma_get_resources(pdev, pdma);
+	if (ret)
+		return ret;
+
+	pdma->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(pdma->clk)) {
+		dev_err(&pdev->dev, "Failed to get clk\n");
+		return PTR_ERR(pdma->clk);
+	}
+
+	/* Enable clk before accessing registers */
+	ret = clk_prepare_enable(pdma->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to enable clk %d\n", ret);
+		return ret;
+	}
+
+	/* Remove DMA RAM out of shutdown */
+	ret = xgene_dma_init_mem(pdma);
+	if (ret)
+		goto err_clk_enable;
+
+	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(42));
+	if (ret) {
+		dev_err(&pdev->dev, "No usable DMA configuration\n");
+		goto err_dma_mask;
+	}
+
+	/* Initialize DMA channels software state */
+	xgene_dma_init_channels(pdma);
+
+	/* Configue DMA rings */
+	ret = xgene_dma_init_rings(pdma);
+	if (ret)
+		goto err_clk_enable;
+
+	ret = xgene_dma_request_irqs(pdma);
+	if (ret)
+		goto err_request_irq;
+
+	/* Configure and enable DMA engine */
+	xgene_dma_init_hw(pdma);
+
+	/* Register DMA device with linux async framework */
+	ret = xgene_dma_init_async(pdma);
+	if (ret)
+		goto err_async_init;
+
+	return 0;
+
+err_async_init:
+	xgene_dma_free_irqs(pdma);
+
+err_request_irq:
+	for (i = 0; i < DMA_MAX_CHANNEL; i++)
+		xgene_dma_delete_chan_rings(&pdma->chan[i]);
+
+err_dma_mask:
+err_clk_enable:
+	clk_disable_unprepare(pdma->clk);
+
+	return ret;
+}
+
+static int xgene_dma_remove(struct platform_device *pdev)
+{
+	struct xgene_dma *pdma = platform_get_drvdata(pdev);
+	struct xgene_dma_chan *chan;
+	int i;
+
+	xgene_dma_async_unregister(pdma);
+
+	/* Mask interrupts and disable DMA engine */
+	xgene_dma_mask_interrupts(pdma);
+	xgene_dma_disable(pdma);
+	xgene_dma_free_irqs(pdma);
+
+	for (i = 0; i < DMA_MAX_CHANNEL; i++) {
+		chan = &pdma->chan[i];
+		tasklet_kill(&chan->tasklet);
+		xgene_dma_delete_chan_rings(chan);
+	}
+
+	clk_disable_unprepare(pdma->clk);
+
+	return 0;
+}
+
+static const struct of_device_id xgene_dma_of_match_ptr[] = {
+	{.compatible = "apm,xgene-dma",},
+	{},
+};
+MODULE_DEVICE_TABLE(of, xgene_dma_of_match_ptr);
+
+static struct platform_driver xgene_dma_driver = {
+	.probe = xgene_dma_probe,
+	.remove = xgene_dma_remove,
+	.driver = {
+		.name = "X-Gene-DMA",
+		.owner = THIS_MODULE,
+		.of_match_table = xgene_dma_of_match_ptr,
+	},
+};
+
+module_platform_driver(xgene_dma_driver);
+
+MODULE_DESCRIPTION("APM X-Gene SoC DMA driver");
+MODULE_AUTHOR("Rameshwar Prasad Sahu <[e-mail]>");
+MODULE_AUTHOR("Loc Ho <[e-mail]>");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.0");