diff mbox

[v14,6/9] HISI LPC: Support the LPC host on Hip06/Hip07 with DT bindings

Message ID 1519062520-198902-7-git-send-email-john.garry@huawei.com (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

John Garry Feb. 19, 2018, 5:48 p.m. UTC
From: Zhichang Yuan <yuanzhichang@hisilicon.com>

The low-pin-count(LPC) interface of Hip06/Hip07 accesses the peripherals in
I/O port addresses. This patch implements the LPC host controller driver
which perform the I/O operations on the underlying hardware.
We don't want to touch those existing peripherals' driver, such as ipmi-bt.
So this driver applies the indirect-IO introduced in the previous patch
after registering an indirect-IO node to the indirect-IO devices list which
will be searched in the I/O accessors to retrieve the host-local I/O port.

The driver config is set as a bool instead of a trisate. The reason
here is that, by the very nature of the driver providing a logical
PIO range, it does not make sense to have this driver as a loadable
module. Another more specific reason is that the Huawei D03 board
which includes hip06 SoC requires the LPC bus for UART console, so
should be built in.

Signed-off-by: Zou Rongrong <zourongrong@huawei.com>
Signed-off-by: Zhichang Yuan <yuanzhichang@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Acked-by: Rob Herring <robh@kernel.org> #dts part
---
 .../arm/hisilicon/hisilicon-low-pin-count.txt      |  33 ++
 drivers/bus/Kconfig                                |   8 +
 drivers/bus/Makefile                               |   1 +
 drivers/bus/hisi_lpc.c                             | 449 +++++++++++++++++++++
 4 files changed, 491 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
 create mode 100644 drivers/bus/hisi_lpc.c

Comments

Andy Shevchenko Feb. 20, 2018, 2:50 p.m. UTC | #1
On Mon, Feb 19, 2018 at 7:48 PM, John Garry <john.garry@huawei.com> wrote:
> From: Zhichang Yuan <yuanzhichang@hisilicon.com>
>
> The low-pin-count(LPC) interface of Hip06/Hip07 accesses the peripherals in
> I/O port addresses. This patch implements the LPC host controller driver
> which perform the I/O operations on the underlying hardware.
> We don't want to touch those existing peripherals' driver, such as ipmi-bt.
> So this driver applies the indirect-IO introduced in the previous patch
> after registering an indirect-IO node to the indirect-IO devices list which
> will be searched in the I/O accessors to retrieve the host-local I/O port.
>
> The driver config is set as a bool instead of a trisate. The reason
> here is that, by the very nature of the driver providing a logical
> PIO range, it does not make sense to have this driver as a loadable
> module. Another more specific reason is that the Huawei D03 board
> which includes hip06 SoC requires the LPC bus for UART console, so
> should be built in.

> +config HISILICON_LPC
> +       bool "Support for ISA I/O space on Hisilicon hip06/7"
> +       depends on (ARM64 && (ARCH_HISI || COMPILE_TEST))

Redundant parens.

> +       select INDIRECT_PIO
> +       help
> +         Driver needed for some legacy ISA devices attached to Low-Pin-Count
> +         on Hisilicon hip06/7 SoC.



> +#if LPC_MAX_DULEN > LPC_MAX_BURST
> +#error "LPC.. MAX_DULEN must be not bigger than MAX_OPCNT!"
> +#endif

But here you can easily avoid an #error, by making them equal, just
issue a warning instead.

> +#if LPC_MAX_BURST % LPC_MAX_DULEN
> +#error "LPC.. LPC_MAX_BURST must be multiple of LPC_MAX_DULEN!"
> +#endif

Is it like this, or also should be power of two?

> +/* The command register fields */
> +#define LPC_CMD_SAMEADDR       0x08
> +#define LPC_CMD_TYPE_IO                0x00

> +#define LPC_CMD_WRITE          0x01
> +#define LPC_CMD_READ           0x00
> +/* the bit attribute is W1C. 1 represents OK. */
> +#define LPC_STAT_BYIRQ         0x02

BIT() ?

> +#define LPC_STATUS_IDLE                0x01
> +#define LPC_OP_FINISHED                0x02
> +
> +#define LPC_START_WORK         0x01

Ditto?

> +static inline int wait_lpc_idle(unsigned char *mbase,
> +                               unsigned int waitcnt) {
> +       u32 opstatus;
> +
> +       while (waitcnt--) {
> +               ndelay(LPC_NSEC_PERWAIT);
> +               opstatus = readl(mbase + LPC_REG_OP_STATUS);
> +               if (opstatus & LPC_STATUS_IDLE)
> +                       return (opstatus & LPC_OP_FINISHED) ? 0 : (-EIO);
> +       }
> +       return -ETIME;

Personally I prefer timeout loops in a do {} while (--count) style.

> +}

> +static int
> +hisi_lpc_target_in(struct hisi_lpc_dev *lpcdev, struct lpc_cycle_para *para,
> +                 unsigned long addr, unsigned char *buf,
> +                 unsigned long opcnt)
> +{
> +       unsigned int cmd_word;
> +       unsigned int waitcnt;
> +       unsigned long flags;
> +       int ret;
> +
> +       if (!buf || !opcnt || !para || !para->csize || !lpcdev)
> +               return -EINVAL;

> +
> +       cmd_word = LPC_CMD_TYPE_IO | LPC_CMD_READ;
> +       waitcnt = LPC_PEROP_WAITCNT;
> +       if (!(para->opflags & FG_INCRADDR_LPC)) {
> +               cmd_word |= LPC_CMD_SAMEADDR;
> +               waitcnt = LPC_MAX_WAITCNT;
> +       }
> +

> +       ret = 0;
> +

Sounds redundant.

> +       /* whole operation must be atomic */
> +       spin_lock_irqsave(&lpcdev->cycle_lock, flags);
> +
> +       writel_relaxed(opcnt, lpcdev->membase + LPC_REG_OP_LEN);
> +
> +       writel_relaxed(cmd_word, lpcdev->membase + LPC_REG_CMD);
> +
> +       writel_relaxed(addr, lpcdev->membase + LPC_REG_ADDR);
> +
> +       writel(LPC_START_WORK, lpcdev->membase + LPC_REG_START);
> +
> +       /* whether the operation is finished */
> +       ret = wait_lpc_idle(lpcdev->membase, waitcnt);

> +       if (!ret) {

I would rather go with usual pattern
if (ret) {
 ...
 return ret;
}


> +               for (; opcnt; opcnt--, buf++)
> +                       *buf = readb(lpcdev->membase + LPC_REG_RDATA);

Looks like a do {} while (slightly better for my opinion).

do {
              *buf++ = readb(lpcdev->membase + LPC_REG_RDATA);
} while (--opcnt);

> +       }
> +
> +       spin_unlock_irqrestore(&lpcdev->cycle_lock, flags);
> +
> +       return ret;
> +}

> +       for (; opcnt; buf++, opcnt--)
> +               writeb(*buf, lpcdev->membase + LPC_REG_WDATA);

Ditto.

> +static u32 hisi_lpc_comm_in(void *hostdata, unsigned long pio, size_t dwidth)

> +       if (!lpcdev || !dwidth || dwidth > LPC_MAX_DULEN)
> +               return -1;

~0 ?

> +       if (ret)
> +               return -1;

Ditto.

> +       do {
> +               int ret;
> +
> +               ret = hisi_lpc_target_in(lpcdev, &iopara, addr,
> +                                       buf, dwidth);
> +               if (ret)
> +                       return ret;
> +               buf += dwidth;

> +               count--;
> +       } while (count);

} while (--count);

> +       do {
> +               if (hisi_lpc_target_out(lpcdev, &iopara, addr, buf,
> +                                               dwidth))
> +                       break;
> +               buf += dwidth;
> +               count--;
> +       } while (count);

Ditto.

> +static int hisi_lpc_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct acpi_device *acpi_device = ACPI_COMPANION(dev);
> +       struct logic_pio_hwaddr *range;
> +       struct hisi_lpc_dev *lpcdev;
> +       struct resource *res;

> +       int ret = 0;

Redundant assignment.

> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

> +       if (!res)
> +               return -ENODEV;

Redundant.

> +
> +       lpcdev->membase = devm_ioremap_resource(dev, res);
> +       if (IS_ERR(lpcdev->membase)) {

> +               dev_err(dev, "remap failed\n");

Redundant.

> +               return PTR_ERR(lpcdev->membase);
> +       }

> +       /* register the LPC host PIO resources */

> +       if (!acpi_device)
> +               ret = of_platform_populate(dev->of_node, NULL, NULL, dev);

> +       if (ret) {

> +               dev_err(dev, "populate children failed (%d)\n", ret);

JFYI: ret is printed by device core if ->probe() fails.

> +               return ret;
> +       }

This condition should go under if (!acpi_device) case.
John Garry Feb. 20, 2018, 3:39 p.m. UTC | #2
On 20/02/2018 14:50, Andy Shevchenko wrote:
> On Mon, Feb 19, 2018 at 7:48 PM, John Garry <john.garry@huawei.com> wrote:
>> From: Zhichang Yuan <yuanzhichang@hisilicon.com>
>>
>> The low-pin-count(LPC) interface of Hip06/Hip07 accesses the peripherals in
>> I/O port addresses. This patch implements the LPC host controller driver
>> which perform the I/O operations on the underlying hardware.
>> We don't want to touch those existing peripherals' driver, such as ipmi-bt.
>> So this driver applies the indirect-IO introduced in the previous patch
>> after registering an indirect-IO node to the indirect-IO devices list which
>> will be searched in the I/O accessors to retrieve the host-local I/O port.
>>
>> The driver config is set as a bool instead of a trisate. The reason
>> here is that, by the very nature of the driver providing a logical
>> PIO range, it does not make sense to have this driver as a loadable
>> module. Another more specific reason is that the Huawei D03 board
>> which includes hip06 SoC requires the LPC bus for UART console, so
>> should be built in.
>

Hi Andy,

>> +config HISILICON_LPC
>> +       bool "Support for ISA I/O space on Hisilicon hip06/7"
>> +       depends on (ARM64 && (ARCH_HISI || COMPILE_TEST))
>
> Redundant parens.

OK, these can be removed

>
>> +       select INDIRECT_PIO
>> +       help
>> +         Driver needed for some legacy ISA devices attached to Low-Pin-Count
>> +         on Hisilicon hip06/7 SoC.
>
>
>
>> +#if LPC_MAX_DULEN > LPC_MAX_BURST
>> +#error "LPC.. MAX_DULEN must be not bigger than MAX_OPCNT!"
>> +#endif
>
> But here you can easily avoid an #error, by making them equal, just
> issue a warning instead.

These values are dictated by the HW. Well the burst length is. 
Regardless I have simplified the driver not to use the burst mode so I 
can remove.

>
>> +#if LPC_MAX_BURST % LPC_MAX_DULEN
>> +#error "LPC.. LPC_MAX_BURST must be multiple of LPC_MAX_DULEN!"
>> +#endif
>
> Is it like this, or also should be power of two?
>

As above

>> +/* The command register fields */
>> +#define LPC_CMD_SAMEADDR       0x08
>> +#define LPC_CMD_TYPE_IO                0x00
>
>> +#define LPC_CMD_WRITE          0x01
>> +#define LPC_CMD_READ           0x00
>> +/* the bit attribute is W1C. 1 represents OK. */
>> +#define LPC_STAT_BYIRQ         0x02
>
> BIT() ?

Not all, but I'll fix them up to be clearer

>
>> +#define LPC_STATUS_IDLE                0x01
>> +#define LPC_OP_FINISHED                0x02
>> +
>> +#define LPC_START_WORK         0x01
>
> Ditto?
>
>> +static inline int wait_lpc_idle(unsigned char *mbase,
>> +                               unsigned int waitcnt) {
>> +       u32 opstatus;
>> +
>> +       while (waitcnt--) {
>> +               ndelay(LPC_NSEC_PERWAIT);
>> +               opstatus = readl(mbase + LPC_REG_OP_STATUS);
>> +               if (opstatus & LPC_STATUS_IDLE)
>> +                       return (opstatus & LPC_OP_FINISHED) ? 0 : (-EIO);
>> +       }
>> +       return -ETIME;
>
> Personally I prefer timeout loops in a do {} while (--count) style.

OK, I think it's fine to change as mentioned

>
>> +}
>
>> +static int
>> +hisi_lpc_target_in(struct hisi_lpc_dev *lpcdev, struct lpc_cycle_para *para,
>> +                 unsigned long addr, unsigned char *buf,
>> +                 unsigned long opcnt)
>> +{
>> +       unsigned int cmd_word;
>> +       unsigned int waitcnt;
>> +       unsigned long flags;
>> +       int ret;
>> +
>> +       if (!buf || !opcnt || !para || !para->csize || !lpcdev)
>> +               return -EINVAL;
>
>> +
>> +       cmd_word = LPC_CMD_TYPE_IO | LPC_CMD_READ;
>> +       waitcnt = LPC_PEROP_WAITCNT;
>> +       if (!(para->opflags & FG_INCRADDR_LPC)) {
>> +               cmd_word |= LPC_CMD_SAMEADDR;
>> +               waitcnt = LPC_MAX_WAITCNT;
>> +       }
>> +
>
>> +       ret = 0;
>> +
>
> Sounds redundant.

it is, so I'll fix

>
>> +       /* whole operation must be atomic */
>> +       spin_lock_irqsave(&lpcdev->cycle_lock, flags);
>> +
>> +       writel_relaxed(opcnt, lpcdev->membase + LPC_REG_OP_LEN);
>> +
>> +       writel_relaxed(cmd_word, lpcdev->membase + LPC_REG_CMD);
>> +
>> +       writel_relaxed(addr, lpcdev->membase + LPC_REG_ADDR);
>> +
>> +       writel(LPC_START_WORK, lpcdev->membase + LPC_REG_START);
>> +
>> +       /* whether the operation is finished */
>> +       ret = wait_lpc_idle(lpcdev->membase, waitcnt);
>
>> +       if (!ret) {
>
> I would rather go with usual pattern
> if (ret) {
>  ...
>  return ret;
> }
>

The intention was to not have 2 calls to free the spinlock. But we can 
go with the usual pattern.

>
>> +               for (; opcnt; opcnt--, buf++)
>> +                       *buf = readb(lpcdev->membase + LPC_REG_RDATA);
>
> Looks like a do {} while (slightly better for my opinion).
>
> do {
>               *buf++ = readb(lpcdev->membase + LPC_REG_RDATA);
> } while (--opcnt);
>

ok

>> +       }
>> +
>> +       spin_unlock_irqrestore(&lpcdev->cycle_lock, flags);
>> +
>> +       return ret;
>> +}
>
>> +       for (; opcnt; buf++, opcnt--)
>> +               writeb(*buf, lpcdev->membase + LPC_REG_WDATA);
>
> Ditto.
>

Ditto

>> +static u32 hisi_lpc_comm_in(void *hostdata, unsigned long pio, size_t dwidth)
>
>> +       if (!lpcdev || !dwidth || dwidth > LPC_MAX_DULEN)
>> +               return -1;
>
> ~0 ?
>

I need to check the patchset for all of these :)

>> +       if (ret)
>> +               return -1;
>
> Ditto.
>
>> +       do {
>> +               int ret;
>> +
>> +               ret = hisi_lpc_target_in(lpcdev, &iopara, addr,
>> +                                       buf, dwidth);
>> +               if (ret)
>> +                       return ret;
>> +               buf += dwidth;
>
>> +               count--;
>> +       } while (count);
>
> } while (--count);
>
>> +       do {
>> +               if (hisi_lpc_target_out(lpcdev, &iopara, addr, buf,
>> +                                               dwidth))
>> +                       break;
>> +               buf += dwidth;
>> +               count--;
>> +       } while (count);
>
> Ditto.

ok, we can use the do-while loop

>
>> +static int hisi_lpc_probe(struct platform_device *pdev)
>> +{
>> +       struct device *dev = &pdev->dev;
>> +       struct acpi_device *acpi_device = ACPI_COMPANION(dev);
>> +       struct logic_pio_hwaddr *range;
>> +       struct hisi_lpc_dev *lpcdev;
>> +       struct resource *res;
>
>> +       int ret = 0;
>
> Redundant assignment.

Right

>
>> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>
>> +       if (!res)
>> +               return -ENODEV;
>
> Redundant.
>

Right, devm_ioremap_resource() can deal with res = NULL.

>> +
>> +       lpcdev->membase = devm_ioremap_resource(dev, res);
>> +       if (IS_ERR(lpcdev->membase)) {
>
>> +               dev_err(dev, "remap failed\n");
>
> Redundant.

right, an error is printed in devm_ioremap_resource()

>
>> +               return PTR_ERR(lpcdev->membase);
>> +       }
>
>> +       /* register the LPC host PIO resources */
>
>> +       if (!acpi_device)
>> +               ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
>
>> +       if (ret) {
>
>> +               dev_err(dev, "populate children failed (%d)\n", ret);
>
> JFYI: ret is printed by device core if ->probe() fails.

OK, so then this is superfluous

>
>> +               return ret;
>> +       }
>
> This condition should go under if (!acpi_device) case.
>

Thanks,
John


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diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt b/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
new file mode 100644
index 0000000..213181f
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
@@ -0,0 +1,33 @@ 
+Hisilicon Hip06 low-pin-count device
+  Hisilicon Hip06 SoCs implement a Low Pin Count (LPC) controller, which
+  provides I/O access to some legacy ISA devices.
+  Hip06 is based on arm64 architecture where there is no I/O space. So, the
+  I/O ports here are not cpu addresses, and there is no 'ranges' property in
+  LPC device node.
+
+Required properties:
+- compatible:  value should be as follows:
+	(a) "hisilicon,hip06-lpc"
+	(b) "hisilicon,hip07-lpc"
+- #address-cells: must be 2 which stick to the ISA/EISA binding doc.
+- #size-cells: must be 1 which stick to the ISA/EISA binding doc.
+- reg: base memory range where the LPC register set is mapped.
+
+Note:
+  The node name before '@' must be "isa" to represent the binding stick to the
+  ISA/EISA binding specification.
+
+Example:
+
+isa@a01b0000 {
+	compatible = "hisilicon,hip06-lpc";
+	#address-cells = <2>;
+	#size-cells = <1>;
+	reg = <0x0 0xa01b0000 0x0 0x1000>;
+
+	ipmi0: bt@e4 {
+		compatible = "ipmi-bt";
+		device_type = "ipmi";
+		reg = <0x01 0xe4 0x04>;
+	};
+};
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index 57e011d..91debe4 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -65,6 +65,14 @@  config BRCMSTB_GISB_ARB
 	  arbiter. This driver provides timeout and target abort error handling
 	  and internal bus master decoding.
 
+config HISILICON_LPC
+	bool "Support for ISA I/O space on Hisilicon hip06/7"
+	depends on (ARM64 && (ARCH_HISI || COMPILE_TEST))
+	select INDIRECT_PIO
+	help
+	  Driver needed for some legacy ISA devices attached to Low-Pin-Count
+	  on Hisilicon hip06/7 SoC.
+
 config IMX_WEIM
 	bool "Freescale EIM DRIVER"
 	depends on ARCH_MXC
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
index 9bcd0bf..abc7a42 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -8,6 +8,7 @@  obj-$(CONFIG_ARM_CCI)		+= arm-cci.o
 obj-$(CONFIG_ARM_CCN)		+= arm-ccn.o
 
 obj-$(CONFIG_BRCMSTB_GISB_ARB)	+= brcmstb_gisb.o
+obj-$(CONFIG_HISILICON_LPC)	+= hisi_lpc.o
 obj-$(CONFIG_IMX_WEIM)		+= imx-weim.o
 obj-$(CONFIG_MIPS_CDMM)		+= mips_cdmm.o
 obj-$(CONFIG_MVEBU_MBUS) 	+= mvebu-mbus.o
diff --git a/drivers/bus/hisi_lpc.c b/drivers/bus/hisi_lpc.c
new file mode 100644
index 0000000..8036291
--- /dev/null
+++ b/drivers/bus/hisi_lpc.c
@@ -0,0 +1,449 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
+ * Author: Zhichang Yuan <yuanzhichang@hisilicon.com>
+ * Author: Zou Rongrong <zourongrong@huawei.com>
+ * Author: John Garry <john.garry@huawei.com>
+ *
+ */
+
+#include <linux/acpi.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/logic_pio.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+
+#define DRV_NAME "hisi-lpc"
+
+/*
+ * Setting this bit means each IO operation will target to a
+ * different port address:
+ * 0 means repeatedly IO operations will stick on the same port,
+ * such as BT;
+ */
+#define FG_INCRADDR_LPC		0x02
+
+struct lpc_cycle_para {
+	unsigned int opflags;
+	unsigned int csize; /* the data length of each operation */
+};
+
+struct hisi_lpc_dev {
+	spinlock_t cycle_lock;
+	void __iomem  *membase;
+	struct logic_pio_hwaddr *io_host;
+};
+
+/* The maximum continuous cycles per burst */
+#define LPC_MAX_BURST	16
+/* The IO cycle counts supported is four per operation at maximum */
+#define LPC_MAX_DULEN	4
+#if LPC_MAX_DULEN > LPC_MAX_BURST
+#error "LPC.. MAX_DULEN must be not bigger than MAX_OPCNT!"
+#endif
+
+#if LPC_MAX_BURST % LPC_MAX_DULEN
+#error "LPC.. LPC_MAX_BURST must be multiple of LPC_MAX_DULEN!"
+#endif
+
+#define LPC_REG_START		0x00 /* start a new LPC cycle */
+#define LPC_REG_OP_STATUS	0x04 /* the current LPC status */
+#define LPC_REG_IRQ_ST		0x08 /* interrupt enable&status */
+#define LPC_REG_OP_LEN		0x10 /* how many LPC cycles each start */
+#define LPC_REG_CMD		0x14 /* command for the required LPC cycle */
+#define LPC_REG_ADDR		0x20 /* LPC target address */
+#define LPC_REG_WDATA		0x24 /* data to be written */
+#define LPC_REG_RDATA		0x28 /* data coming from peer */
+
+
+/* The command register fields */
+#define LPC_CMD_SAMEADDR	0x08
+#define LPC_CMD_TYPE_IO		0x00
+#define LPC_CMD_WRITE		0x01
+#define LPC_CMD_READ		0x00
+/* the bit attribute is W1C. 1 represents OK. */
+#define LPC_STAT_BYIRQ		0x02
+
+#define LPC_STATUS_IDLE		0x01
+#define LPC_OP_FINISHED		0x02
+
+#define LPC_START_WORK		0x01
+
+/* The minimal nanosecond interval for each query on LPC cycle status. */
+#define LPC_NSEC_PERWAIT	100
+
+/*
+ * The maximum waiting time is about 128us.
+ * It is specific for stream I/O, such as ins.
+ * The fastest IO cycle time is about 390ns, but the worst case will wait
+ * for extra 256 lpc clocks, so (256 + 13) * 30ns = 8 us. The maximum
+ * burst cycles is 16. So, the maximum waiting time is about 128us under
+ * worst case.
+ * choose 1300 as the maximum.
+ */
+#define LPC_MAX_WAITCNT		1300
+/* About 10us. This is specific for single IO operation, such as inb. */
+#define LPC_PEROP_WAITCNT	100
+
+static inline int wait_lpc_idle(unsigned char *mbase,
+				unsigned int waitcnt) {
+	u32 opstatus;
+
+	while (waitcnt--) {
+		ndelay(LPC_NSEC_PERWAIT);
+		opstatus = readl(mbase + LPC_REG_OP_STATUS);
+		if (opstatus & LPC_STATUS_IDLE)
+			return (opstatus & LPC_OP_FINISHED) ? 0 : (-EIO);
+	}
+	return -ETIME;
+}
+
+/*
+ * hisi_lpc_target_in - trigger a series of LPC cycles for read operation
+ * @lpcdev: pointer to hisi lpc device
+ * @para: some parameters used to control the lpc I/O operations
+ * @addr: the lpc I/O target port address
+ * @buf: where the read back data is stored
+ * @opcnt: how many I/O operations required, i.e. data width
+ *
+ * Returns 0 on success, non-zero on fail.
+ */
+static int
+hisi_lpc_target_in(struct hisi_lpc_dev *lpcdev, struct lpc_cycle_para *para,
+		  unsigned long addr, unsigned char *buf,
+		  unsigned long opcnt)
+{
+	unsigned int cmd_word;
+	unsigned int waitcnt;
+	unsigned long flags;
+	int ret;
+
+	if (!buf || !opcnt || !para || !para->csize || !lpcdev)
+		return -EINVAL;
+
+	cmd_word = LPC_CMD_TYPE_IO | LPC_CMD_READ;
+	waitcnt = LPC_PEROP_WAITCNT;
+	if (!(para->opflags & FG_INCRADDR_LPC)) {
+		cmd_word |= LPC_CMD_SAMEADDR;
+		waitcnt = LPC_MAX_WAITCNT;
+	}
+
+	ret = 0;
+
+	/* whole operation must be atomic */
+	spin_lock_irqsave(&lpcdev->cycle_lock, flags);
+
+	writel_relaxed(opcnt, lpcdev->membase + LPC_REG_OP_LEN);
+
+	writel_relaxed(cmd_word, lpcdev->membase + LPC_REG_CMD);
+
+	writel_relaxed(addr, lpcdev->membase + LPC_REG_ADDR);
+
+	writel(LPC_START_WORK, lpcdev->membase + LPC_REG_START);
+
+	/* whether the operation is finished */
+	ret = wait_lpc_idle(lpcdev->membase, waitcnt);
+	if (!ret) {
+		for (; opcnt; opcnt--, buf++)
+			*buf = readb(lpcdev->membase + LPC_REG_RDATA);
+	}
+
+	spin_unlock_irqrestore(&lpcdev->cycle_lock, flags);
+
+	return ret;
+}
+
+/*
+ * hisi_lpc_target_out - trigger a series of LPC cycles for write operation
+ * @lpcdev: pointer to hisi lpc device
+ * @para: some parameters used to control the lpc I/O operations
+ * @addr: the lpc I/O target port address
+ * @buf: where the data to be written is stored
+ * @opcnt: how many I/O operations required, i.e. data width
+ *
+ * Returns 0 on success, non-zero on fail.
+ */
+static int
+hisi_lpc_target_out(struct hisi_lpc_dev *lpcdev, struct lpc_cycle_para *para,
+		    unsigned long addr, const unsigned char *buf,
+		    unsigned long opcnt)
+{
+	unsigned int cmd_word;
+	unsigned int waitcnt;
+	unsigned long flags;
+	int ret;
+
+	if (!buf || !opcnt || !para || !lpcdev)
+		return -EINVAL;
+
+	/* default is increasing address */
+	cmd_word = LPC_CMD_TYPE_IO | LPC_CMD_WRITE;
+	waitcnt = LPC_PEROP_WAITCNT;
+	if (!(para->opflags & FG_INCRADDR_LPC)) {
+		cmd_word |= LPC_CMD_SAMEADDR;
+		waitcnt = LPC_MAX_WAITCNT;
+	}
+
+	spin_lock_irqsave(&lpcdev->cycle_lock, flags);
+
+	writel_relaxed(opcnt, lpcdev->membase + LPC_REG_OP_LEN);
+	writel_relaxed(cmd_word, lpcdev->membase + LPC_REG_CMD);
+	writel_relaxed(addr, lpcdev->membase + LPC_REG_ADDR);
+
+	for (; opcnt; buf++, opcnt--)
+		writeb(*buf, lpcdev->membase + LPC_REG_WDATA);
+
+	writel(LPC_START_WORK, lpcdev->membase + LPC_REG_START);
+
+	/* whether the operation is finished */
+	ret = wait_lpc_idle(lpcdev->membase, waitcnt);
+
+	spin_unlock_irqrestore(&lpcdev->cycle_lock, flags);
+
+	return ret;
+}
+
+static inline unsigned long
+hisi_lpc_pio_to_addr(struct hisi_lpc_dev *lpcdev, unsigned long pio)
+{
+	return pio - lpcdev->io_host->io_start +
+		lpcdev->io_host->hw_start;
+}
+
+/*
+ * hisi_lpc_comm_in - input the data in a single operation
+ * @hostdata: pointer to the device information relevant to LPC controller.
+ * @pio: the target I/O port address.
+ * @dwidth: the data length required to read from the target I/O port.
+ *
+ * When success, data is returned. Otherwise, -1 is returned.
+ */
+static u32 hisi_lpc_comm_in(void *hostdata, unsigned long pio, size_t dwidth)
+{
+	struct hisi_lpc_dev *lpcdev = hostdata;
+	struct lpc_cycle_para iopara;
+	u32 rd_data = 0;
+	unsigned long addr;
+	int ret = 0;
+
+	if (!lpcdev || !dwidth || dwidth > LPC_MAX_DULEN)
+		return -1;
+
+	addr = hisi_lpc_pio_to_addr(lpcdev, pio);
+
+	iopara.opflags = FG_INCRADDR_LPC;
+	iopara.csize = dwidth;
+
+	ret = hisi_lpc_target_in(lpcdev, &iopara, addr,
+				 (unsigned char *)&rd_data, dwidth);
+	if (ret)
+		return -1;
+
+	return le32_to_cpu(rd_data);
+}
+
+/*
+ * hisi_lpc_comm_out - output the data in a single operation
+ * @hostdata: pointer to the device information relevant to LPC controller.
+ * @pio: the target I/O port address.
+ * @val: a value to be outputted from caller, maximum is four bytes.
+ * @dwidth: the data width required writing to the target I/O port.
+ *
+ * This function is corresponding to out(b,w,l) only
+ *
+ */
+static void hisi_lpc_comm_out(void *hostdata, unsigned long pio,
+			     u32 val, size_t dwidth)
+{
+	struct hisi_lpc_dev *lpcdev = hostdata;
+	struct lpc_cycle_para iopara;
+	const unsigned char *buf;
+	unsigned long addr;
+
+	if (!lpcdev || !dwidth || dwidth > LPC_MAX_DULEN)
+		return;
+
+	val = cpu_to_le32(val);
+
+	buf = (const unsigned char *)&val;
+	addr = hisi_lpc_pio_to_addr(lpcdev, pio);
+
+	iopara.opflags = FG_INCRADDR_LPC;
+	iopara.csize = dwidth;
+
+	hisi_lpc_target_out(lpcdev, &iopara, addr, buf, dwidth);
+}
+
+/*
+ * hisi_lpc_comm_ins - input the data in the buffer in multiple operations
+ * @hostdata: pointer to the device information relevant to LPC controller.
+ * @pio: the target I/O port address.
+ * @buffer: a buffer where read/input data bytes are stored.
+ * @dwidth: the data width required writing to the target I/O port.
+ * @count: how many data units whose length is dwidth will be read.
+ *
+ * When success, the data read back is stored in buffer pointed by buffer.
+ * Returns 0 on success, -errno otherwise
+ *
+ */
+static u32
+hisi_lpc_comm_ins(void *hostdata, unsigned long pio, void *buffer,
+		  size_t dwidth, unsigned int count)
+{
+	struct hisi_lpc_dev *lpcdev = hostdata;
+	unsigned char *buf = buffer;
+	struct lpc_cycle_para iopara;
+	unsigned long addr;
+
+	if (!lpcdev || !buf || !count || !dwidth || dwidth > LPC_MAX_DULEN)
+		return -EINVAL;
+
+	iopara.opflags = 0;
+	if (dwidth > 1)
+		iopara.opflags |= FG_INCRADDR_LPC;
+	iopara.csize = dwidth;
+
+	addr = hisi_lpc_pio_to_addr(lpcdev, pio);
+
+	do {
+		int ret;
+
+		ret = hisi_lpc_target_in(lpcdev, &iopara, addr,
+					buf, dwidth);
+		if (ret)
+			return ret;
+		buf += dwidth;
+		count--;
+	} while (count);
+
+	return 0;
+}
+
+/*
+ * hisi_lpc_comm_outs - output the data in the buffer in multiple operations
+ * @hostdata: pointer to the device information relevant to LPC controller.
+ * @pio: the target I/O port address.
+ * @buffer: a buffer where write/output data bytes are stored.
+ * @dwidth: the data width required writing to the target I/O port .
+ * @count: how many data units whose length is dwidth will be written.
+ *
+ */
+static void
+hisi_lpc_comm_outs(void *hostdata, unsigned long pio, const void *buffer,
+		   size_t dwidth, unsigned int count)
+{
+	struct hisi_lpc_dev *lpcdev = hostdata;
+	struct lpc_cycle_para iopara;
+	const unsigned char *buf = buffer;
+	unsigned long addr;
+
+	if (!lpcdev || !buf || !count || !dwidth || dwidth > LPC_MAX_DULEN)
+		return;
+
+	iopara.opflags = 0;
+	if (dwidth > 1)
+		iopara.opflags |= FG_INCRADDR_LPC;
+	iopara.csize = dwidth;
+
+	addr = hisi_lpc_pio_to_addr(lpcdev, pio);
+	do {
+		if (hisi_lpc_target_out(lpcdev, &iopara, addr, buf,
+						dwidth))
+			break;
+		buf += dwidth;
+		count--;
+	} while (count);
+}
+
+static const struct logic_pio_host_ops hisi_lpc_ops = {
+	.in = hisi_lpc_comm_in,
+	.out = hisi_lpc_comm_out,
+	.ins = hisi_lpc_comm_ins,
+	.outs = hisi_lpc_comm_outs,
+};
+
+/*
+ * hisi_lpc_probe - the probe callback function for hisi lpc host,
+ *		   will finish all the initialization.
+ * @pdev: the platform device corresponding to hisi lpc host
+ *
+ * Returns 0 on success, non-zero on fail.
+ */
+static int hisi_lpc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct acpi_device *acpi_device = ACPI_COMPANION(dev);
+	struct logic_pio_hwaddr *range;
+	struct hisi_lpc_dev *lpcdev;
+	struct resource *res;
+	int ret = 0;
+
+	lpcdev = devm_kzalloc(dev, sizeof(struct hisi_lpc_dev), GFP_KERNEL);
+	if (!lpcdev)
+		return -ENOMEM;
+
+	spin_lock_init(&lpcdev->cycle_lock);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	lpcdev->membase = devm_ioremap_resource(dev, res);
+	if (IS_ERR(lpcdev->membase)) {
+		dev_err(dev, "remap failed\n");
+		return PTR_ERR(lpcdev->membase);
+	}
+
+	range = devm_kzalloc(dev, sizeof(*range), GFP_KERNEL);
+	if (!range)
+		return -ENOMEM;
+	range->fwnode = dev->fwnode;
+	range->flags = PIO_INDIRECT;
+	range->size = PIO_INDIRECT_SIZE;
+
+	ret = logic_pio_register_range(range);
+	if (ret) {
+		dev_err(dev, "register IO range failed (%d)!\n", ret);
+		return ret;
+	}
+	lpcdev->io_host = range;
+
+	/* register the LPC host PIO resources */
+	if (!acpi_device)
+		ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
+	if (ret) {
+		dev_err(dev, "populate children failed (%d)\n", ret);
+		return ret;
+	}
+
+	lpcdev->io_host->hostdata = lpcdev;
+	lpcdev->io_host->ops = &hisi_lpc_ops;
+
+	dev_info(dev, "registered range[%pa - sz:%pa]\n",
+		 &lpcdev->io_host->io_start,
+		 &lpcdev->io_host->size);
+
+	return ret;
+}
+
+static const struct of_device_id hisi_lpc_of_match[] = {
+	{ .compatible = "hisilicon,hip06-lpc", },
+	{ .compatible = "hisilicon,hip07-lpc", },
+	{}
+};
+
+static struct platform_driver hisi_lpc_driver = {
+	.driver = {
+		.name           = DRV_NAME,
+		.of_match_table = hisi_lpc_of_match,
+	},
+	.probe = hisi_lpc_probe,
+};
+
+builtin_platform_driver(hisi_lpc_driver);