diff mbox

[v16,3/4] ata: Add APM X-Gene SoC AHCI SATA host controller driver

Message ID 1394575895-7039-4-git-send-email-lho@apm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Loc Ho March 11, 2014, 10:11 p.m. UTC
This patch adds support for the APM X-Gene SoC AHCI SATA host controller
driver. It requires the corresponding APM X-Gene SoC PHY driver. This
initial version only supports Gen3 speed.

Signed-off-by: Loc Ho <lho@apm.com>
Signed-off-by: Tuan Phan <tphan@apm.com>
Signed-off-by: Suman Tripathi <stripathi@apm.com>
---
 drivers/ata/Kconfig      |    7 +
 drivers/ata/Makefile     |    1 +
 drivers/ata/ahci_xgene.c |  490 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 498 insertions(+), 0 deletions(-)
 create mode 100644 drivers/ata/ahci_xgene.c

Comments

Bartlomiej Zolnierkiewicz March 12, 2014, 6:10 p.m. UTC | #1
Hi,

Thanks for updating this patch, there are still some issue left though
(please see below).

On Tuesday, March 11, 2014 04:11:34 PM Loc Ho wrote:
> This patch adds support for the APM X-Gene SoC AHCI SATA host controller
> driver. It requires the corresponding APM X-Gene SoC PHY driver. This
> initial version only supports Gen3 speed.
> 
> Signed-off-by: Loc Ho <lho@apm.com>
> Signed-off-by: Tuan Phan <tphan@apm.com>
> Signed-off-by: Suman Tripathi <stripathi@apm.com>
> ---
>  drivers/ata/Kconfig      |    7 +
>  drivers/ata/Makefile     |    1 +
>  drivers/ata/ahci_xgene.c |  490 ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 498 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/ata/ahci_xgene.c
> 
> diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
> index 93fc2f0..9de4ca5 100644
> --- a/drivers/ata/Kconfig
> +++ b/drivers/ata/Kconfig
> @@ -115,6 +115,13 @@ config AHCI_SUNXI
>  
>  	  If unsure, say N.
>  
> +config AHCI_XGENE
> +	tristate "APM X-Gene 6.0Gbps AHCI SATA host controller support"
> +	depends on SATA_AHCI_PLATFORM && (ARM64 || COMPILE_TEST)
> +	select PHY_XGENE
> +	help
> +	 This option enables support for APM X-Gene SoC SATA host controller.
> +
>  config SATA_FSL
>  	tristate "Freescale 3.0Gbps SATA support"
>  	depends on FSL_SOC
> diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
> index 246050b..72b423b 100644
> --- a/drivers/ata/Makefile
> +++ b/drivers/ata/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_SATA_DWC)		+= sata_dwc_460ex.o
>  obj-$(CONFIG_SATA_HIGHBANK)	+= sata_highbank.o libahci.o
>  obj-$(CONFIG_AHCI_IMX)		+= ahci_imx.o
>  obj-$(CONFIG_AHCI_SUNXI)	+= ahci_sunxi.o
> +obj-$(CONFIG_AHCI_XGENE)	+= ahci_xgene.o
>  
>  # SFF w/ custom DMA
>  obj-$(CONFIG_PDC_ADMA)		+= pdc_adma.o
> diff --git a/drivers/ata/ahci_xgene.c b/drivers/ata/ahci_xgene.c
> new file mode 100644
> index 0000000..df37c78
> --- /dev/null
> +++ b/drivers/ata/ahci_xgene.c

[...]

> +static struct ata_port_operations xgene_ahci_ops = {
> +	.inherits = &ahci_ops,
> +	.hardreset = xgene_ahci_hardreset,
> +	.read_id = xgene_ahci_read_id,
> +};

[...]

> +static int xgene_ahci_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct ahci_host_priv *hpriv;
> +	struct xgene_ahci_context *ctx;
> +	struct resource *res;
> +	int rc;
> +
> +	hpriv = ahci_platform_get_resources(pdev);
> +	if (IS_ERR(hpriv))
> +		return PTR_ERR(hpriv);
> +
> +	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
> +	if (!ctx) {
> +		dev_err(dev, "can't allocate host context\n");
> +		return -ENOMEM;
> +	}
> +	hpriv->plat_data = ctx;
> +	ctx->hpriv = hpriv;
> +	ctx->dev = dev;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +	if (!res) {
> +		dev_err(dev, "no csr space\n");
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * Can't use devm_ioremap_resource due to overlapping region.
> +	 * 0xYYYY.0000 - host core
> +	 * 0xYYYY.7000 - Mux (if applicable)
> +	 * 0xYYYY.A000 - PHY indirect access
> +	 * 0xYYYY.C000 - Clock
> +	 * 0xYYYY.D000 - RAM shutdown removal
> +	 * As we map the entire region as one, it overlaps with the PHY driver.
> +	 */
> +	ctx->csr_base = devm_ioremap(dev, res->start, resource_size(res));
> +	if (!ctx->csr_base) {
> +		dev_err(dev, "can't map %pR\n", res);
> +		return -ENOMEM;
> +	}
> +
> +	dev_dbg(dev, "VAddr 0x%p Mmio VAddr 0x%p\n", ctx->csr_base,
> +		hpriv->mmio);
> +
> +	/* Select ATA */
> +	if (of_device_is_compatible(pdev->dev.of_node,
> +		XGENE_AHCI_SGMII_DTS)) {
> +		if (xgene_ahci_mux_select(ctx)) {
> +			dev_err(dev, "SATA mux selection failed\n");
> +			return -ENODEV;
> +		}
> +	}
> +
> +	/* Due to errata, HW requires full toggle transition */
> +	rc = ahci_platform_enable_clks(hpriv);
> +	if (rc)
> +		goto disable_resources;
> +	ahci_platform_disable_clks(hpriv);
> +
> +	rc = ahci_platform_enable_resources(hpriv);
> +	if (rc)
> +		goto disable_resources;
> +
> +	/* Configure the host controller */
> +	xgene_ahci_hw_init(hpriv);
> +
> +	/* Setup DMA mask - 32 for 32-bit system and 64 for 64-bit system */
> +	rc = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(8*sizeof(void *)));
> +	if (rc) {
> +		dev_err(dev, "Unable to set dma mask\n");
> +		phy_exit(hpriv->phy);
> +		goto disable_resources;

Since the code has been switched to use generic ahci_platform ->phy
support phy_exit() is now handled by ahci_platform_disable_resources()
and the direct call should be removed.

> +	}
> +
> +	rc = ahci_platform_init_host(pdev, hpriv, &xgene_ahci_port_info, 0, 0);
> +	if (rc) {
> +		phy_exit(hpriv->phy);

ditto

> +		goto disable_resources;
> +	}
> +
> +	dev_dbg(dev, "X-Gene SATA host controller initialized\n");
> +	return 0;
> +
> +disable_resources:
> +	ahci_platform_disable_resources(hpriv);
> +	return rc;
> +}
> +
> +static const struct of_device_id xgene_ahci_of_match[] = {
> +	{.compatible = XGENE_AHCI_SGMII_DTS,},
> +	{.compatible = XGENE_AHCI_PCIE_DTS,},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, xgene_ahci_of_match);
> +
> +static struct platform_driver xgene_ahci_driver = {
> +	.probe = xgene_ahci_probe,
> +	.remove = ata_platform_remove_one,

It is good to use ata_platform_remove_one() here but some code still needs
to callback ahci_platform_disable_resources() before the driver is removed
completely.  The way other drivers do it is to define custom ->host_stop
method and add it to port ops (xgene_ahci_ops in this case).  For X-Gene
AHCI driver ->host_stop function can be quite simple and look like this:

static void xgene_ahci_host_stop(struct ata_host *host)
{
	struct ahci_host_priv *hpriv = host->private_data;

	ahci_platform_disable_resources(hpriv);
}

> +	.driver = {
> +		.name = "xgene-ahci",
> +		.owner = THIS_MODULE,
> +		.of_match_table = xgene_ahci_of_match,
> +	},

Power Management support is missing for this driver.  If your platform
doesn't support Suspend to RAM yet it would be good to add a comment
about this explaining the lack of PM.  Otherwise it should be fixed (you
can take a look at ahci_imx.c and ahci_sunxi.c for examples).

Otherwise the driver looks good to me and (FWIW) you can add:

	Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

Once the aforementioned issues are fixed.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
Loc Ho March 12, 2014, 7:01 p.m. UTC | #2
Hi,

>> +MODULE_DEVICE_TABLE(of, xgene_ahci_of_match);
>> +
>> +static struct platform_driver xgene_ahci_driver = {
>> +     .probe = xgene_ahci_probe,
>> +     .remove = ata_platform_remove_one,
>
> It is good to use ata_platform_remove_one() here but some code still needs
> to callback ahci_platform_disable_resources() before the driver is removed
> completely.  The way other drivers do it is to define custom ->host_stop
> method and add it to port ops (xgene_ahci_ops in this case).  For X-Gene
> AHCI driver ->host_stop function can be quite simple and look like this:
>
> static void xgene_ahci_host_stop(struct ata_host *host)
> {
>         struct ahci_host_priv *hpriv = host->private_data;
>
>         ahci_platform_disable_resources(hpriv);
> }

Will do.

>
>> +     .driver = {
>> +             .name = "xgene-ahci",
>> +             .owner = THIS_MODULE,
>> +             .of_match_table = xgene_ahci_of_match,
>> +     },
>
> Power Management support is missing for this driver.  If your platform
> doesn't support Suspend to RAM yet it would be good to add a comment
> about this explaining the lack of PM.  Otherwise it should be fixed (you
> can take a look at ahci_imx.c and ahci_sunxi.c for examples).

In order to support PM, I will need an other errata fix in libachi.c.
For now PM, will NOT be support.

>
> Otherwise the driver looks good to me and (FWIW) you can add:
>
>         Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
>
> Once the aforementioned issues are fixed.

I will post another version. If you ack'ed that version, Tejun can add
you to the Reviewed-by list.

-Loc
diff mbox

Patch

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index 93fc2f0..9de4ca5 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -115,6 +115,13 @@  config AHCI_SUNXI
 
 	  If unsure, say N.
 
+config AHCI_XGENE
+	tristate "APM X-Gene 6.0Gbps AHCI SATA host controller support"
+	depends on SATA_AHCI_PLATFORM && (ARM64 || COMPILE_TEST)
+	select PHY_XGENE
+	help
+	 This option enables support for APM X-Gene SoC SATA host controller.
+
 config SATA_FSL
 	tristate "Freescale 3.0Gbps SATA support"
 	depends on FSL_SOC
diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
index 246050b..72b423b 100644
--- a/drivers/ata/Makefile
+++ b/drivers/ata/Makefile
@@ -12,6 +12,7 @@  obj-$(CONFIG_SATA_DWC)		+= sata_dwc_460ex.o
 obj-$(CONFIG_SATA_HIGHBANK)	+= sata_highbank.o libahci.o
 obj-$(CONFIG_AHCI_IMX)		+= ahci_imx.o
 obj-$(CONFIG_AHCI_SUNXI)	+= ahci_sunxi.o
+obj-$(CONFIG_AHCI_XGENE)	+= ahci_xgene.o
 
 # SFF w/ custom DMA
 obj-$(CONFIG_PDC_ADMA)		+= pdc_adma.o
diff --git a/drivers/ata/ahci_xgene.c b/drivers/ata/ahci_xgene.c
new file mode 100644
index 0000000..df37c78
--- /dev/null
+++ b/drivers/ata/ahci_xgene.c
@@ -0,0 +1,490 @@ 
+/*
+ * AppliedMicro X-Gene SoC SATA Host Controller Driver
+ *
+ * Copyright (c) 2014, Applied Micro Circuits Corporation
+ * Author: Loc Ho <lho@apm.com>
+ *         Tuan Phan <tphan@apm.com>
+ *         Suman Tripathi <stripathi@apm.com>
+ *
+ * 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/>.
+ *
+ */
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/ahci_platform.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/phy/phy.h>
+#include "ahci.h"
+
+/* Controller who PHY shared with SGMII Ethernet PHY */
+#define XGENE_AHCI_SGMII_DTS		"apm,xgene-ahci-sgmii"
+
+/* Controller who PHY (internal reference clock macro) shared with PCIe */
+#define XGENE_AHCI_PCIE_DTS		"apm,xgene-ahci-pcie"
+
+/* Max # of disk per a controller */
+#define MAX_AHCI_CHN_PERCTR		2
+
+#define SATA_ENET_MUX_OFFSET		0x00007000
+#define SATA_DIAG_OFFSET		0x0000D000
+#define SATA_GLB_OFFSET			0x0000D850
+#define SATA_SHIM_OFFSET		0x0000E000
+#define SATA_MASTER_OFFSET		0x0000F000
+#define SATA_PORT0_OFFSET		0x00000100
+#define SATA_PORT1_OFFSET		0x00000180
+
+/* MUX CSR */
+#define SATA_ENET_CONFIG_REG		0x00000000
+#define  CFG_SATA_ENET_SELECT_MASK	0x00000001
+
+/* SATA host controller CSR */
+#define SLVRDERRATTRIBUTES		0x00000000
+#define SLVWRERRATTRIBUTES		0x00000004
+#define MSTRDERRATTRIBUTES		0x00000008
+#define MSTWRERRATTRIBUTES		0x0000000c
+#define BUSCTLREG			0x00000014
+#define IOFMSTRWAUX			0x00000018
+#define INTSTATUSMASK			0x0000002c
+#define ERRINTSTATUS			0x00000030
+#define ERRINTSTATUSMASK		0x00000034
+
+/* SATA host AHCI CSR */
+#define PORTCFG				0x000000a4
+#define  PORTADDR_SET(dst, src) \
+		(((dst) & ~0x0000003f) | (((u32)(src)) & 0x0000003f))
+#define PORTPHY1CFG		0x000000a8
+#define PORTPHY1CFG_FRCPHYRDY_SET(dst, src) \
+		(((dst) & ~0x00100000) | (((u32)(src) << 0x14) & 0x00100000))
+#define PORTPHY2CFG			0x000000ac
+#define PORTPHY3CFG			0x000000b0
+#define PORTPHY4CFG			0x000000b4
+#define PORTPHY5CFG			0x000000b8
+#define SCTL0				0x0000012C
+#define PORTPHY5CFG_RTCHG_SET(dst, src) \
+		(((dst) & ~0xfff00000) | (((u32)(src) << 0x14) & 0xfff00000))
+#define PORTAXICFG_EN_CONTEXT_SET(dst, src) \
+		(((dst) & ~0x01000000) | (((u32)(src) << 0x18) & 0x01000000))
+#define PORTAXICFG			0x000000bc
+#define PORTAXICFG_OUTTRANS_SET(dst, src) \
+		(((dst) & ~0x00f00000) | (((u32)(src) << 0x14) & 0x00f00000))
+
+/* SATA host controller slave CSR */
+#define INT_SLV_TMOMASK			0x00000010
+
+/* SATA global diagnostic CSR */
+#define CFG_MEM_RAM_SHUTDOWN		0x00000070
+#define BLOCK_MEM_RDY			0x00000074
+
+struct xgene_ahci_context {
+	struct ahci_host_priv *hpriv;
+	struct device *dev;
+	void __iomem *csr_base;		/* CSR base address of IP */
+};
+
+static int xgene_ahci_init_memram(struct xgene_ahci_context *ctx)
+{
+	void __iomem *diagcsr = ctx->csr_base + SATA_DIAG_OFFSET;
+
+	dev_dbg(ctx->dev, "Release memory from shutdown\n");
+	writel(0x0, diagcsr + CFG_MEM_RAM_SHUTDOWN);
+	readl(diagcsr + CFG_MEM_RAM_SHUTDOWN); /* Force a barrier */
+	msleep(1);	/* reset may take up to 1ms */
+	if (readl(diagcsr + BLOCK_MEM_RDY) != 0xFFFFFFFF) {
+		dev_err(ctx->dev, "failed to release memory from shutdown\n");
+		return -ENODEV;
+	}
+	return 0;
+}
+
+/**
+ * xgene_ahci_read_id - Read ID data from the specified device
+ * @dev: device
+ * @tf: proposed taskfile
+ * @id: data buffer
+ *
+ * This custom read ID function is required due to the fact that the HW
+ * does not support DEVSLP and the controller state machine may get stuck
+ * after processing the ID query command.
+ */
+static unsigned int xgene_ahci_read_id(struct ata_device *dev,
+				       struct ata_taskfile *tf, u16 *id)
+{
+	u32 err_mask;
+	void __iomem *port_mmio = ahci_port_base(dev->link->ap);
+
+	err_mask = ata_do_dev_read_id(dev, tf, id);
+	if (err_mask)
+		return err_mask;
+
+	/*
+	 * Mask reserved area. Word78 spec of Link Power Management
+	 * bit15-8: reserved
+	 * bit7: NCQ autosence
+	 * bit6: Software settings preservation supported
+	 * bit5: reserved
+	 * bit4: In-order sata delivery supported
+	 * bit3: DIPM requests supported
+	 * bit2: DMA Setup FIS Auto-Activate optimization supported
+	 * bit1: DMA Setup FIX non-Zero buffer offsets supported
+	 * bit0: Reserved
+	 *
+	 * Clear reserved bit 8 (DEVSLP bit) as we don't support DEVSLP
+	 */
+	id[ATA_ID_FEATURE_SUPP] &= ~(1 << 8);
+
+	/*
+	 * Due to HW errata, restart the port if no other command active.
+	 * Otherwise the controller may get stuck.
+	 */
+	if (!readl(port_mmio + PORT_CMD_ISSUE)) {
+		writel(PORT_CMD_FIS_RX, port_mmio + PORT_CMD);
+		readl(port_mmio + PORT_CMD);	/* Force a barrier */
+		writel(PORT_CMD_FIS_RX | PORT_CMD_START, port_mmio + PORT_CMD);
+		readl(port_mmio + PORT_CMD);	/* Force a barrier */
+	}
+	return 0;
+}
+
+static void xgene_ahci_set_phy_cfg(struct xgene_ahci_context *ctx, int channel)
+{
+	void __iomem *mmio = ctx->hpriv->mmio;
+	u32 val;
+
+	dev_dbg(ctx->dev, "port configure mmio 0x%p channel %d\n",
+		mmio, channel);
+	val = readl(mmio + PORTCFG);
+	val = PORTADDR_SET(val, channel == 0 ? 2 : 3);
+	writel(val, mmio + PORTCFG);
+	readl(mmio + PORTCFG);  /* Force a barrier */
+	/* Disable fix rate */
+	writel(0x0001fffe, mmio + PORTPHY1CFG);
+	readl(mmio + PORTPHY1CFG); /* Force a barrier */
+	writel(0x5018461c, mmio + PORTPHY2CFG);
+	readl(mmio + PORTPHY2CFG); /* Force a barrier */
+	writel(0x1c081907, mmio + PORTPHY3CFG);
+	readl(mmio + PORTPHY3CFG); /* Force a barrier */
+	writel(0x1c080815, mmio + PORTPHY4CFG);
+	readl(mmio + PORTPHY4CFG); /* Force a barrier */
+	/* Set window negotiation */
+	val = readl(mmio + PORTPHY5CFG);
+	val = PORTPHY5CFG_RTCHG_SET(val, 0x300);
+	writel(val, mmio + PORTPHY5CFG);
+	readl(mmio + PORTPHY5CFG); /* Force a barrier */
+	val = readl(mmio + PORTAXICFG);
+	val = PORTAXICFG_EN_CONTEXT_SET(val, 0x1); /* Enable context mgmt */
+	val = PORTAXICFG_OUTTRANS_SET(val, 0xe); /* Set outstanding */
+	writel(val, mmio + PORTAXICFG);
+	readl(mmio + PORTAXICFG); /* Force a barrier */
+}
+
+/**
+ * xgene_ahci_do_hardreset - Issue the actual COMRESET
+ * @link: link to reset
+ * @deadline: deadline jiffies for the operation
+ * @online: Return value to indicate if device online
+ *
+ * Due to the limitation of the hardware PHY, a difference set of setting is
+ * required for each supported disk speed - Gen3 (6.0Gbps), Gen2 (3.0Gbps),
+ * and Gen1 (1.5Gbps). Otherwise during long IO stress test, the PHY will
+ * report disparity error and etc. In addition, during COMRESET, there can
+ * be error reported in the register PORT_SCR_ERR. For SERR_DISPARITY and
+ * SERR_10B_8B_ERR, the PHY receiver line must be reseted. The following
+ * algorithm is followed to proper configure the hardware PHY during COMRESET:
+ *
+ * Alg Part 1:
+ * 1. Start the PHY at Gen3 speed (default setting)
+ * 2. Issue the COMRESET
+ * 3. If no link, go to Alg Part 3
+ * 4. If link up, determine if the negotiated speed matches the PHY
+ *    configured speed
+ * 5. If they matched, go to Alg Part 2
+ * 6. If they do not matched and first time, configure the PHY for the linked
+ *    up disk speed and repeat step 2
+ * 7. Go to Alg Part 2
+ *
+ * Alg Part 2:
+ * 1. On link up, if there are any SERR_DISPARITY and SERR_10B_8B_ERR error
+ *    reported in the register PORT_SCR_ERR, then reset the PHY receiver line
+ * 2. Go to Alg Part 3
+ *
+ * Alg Part 3:
+ * 1. Clear any pending from register PORT_SCR_ERR.
+ *
+ * NOTE: First the initial version, we will NOT support Gen1/Gen2. In addition
+ *       and until the underlying PHY support an method to reset the receiver
+ *       line, on detection of SERR_DISPARITY or SERR_10B_8B_ERR error,
+ *       an warning message will be printed.
+ */
+static int xgene_ahci_do_hardreset(struct ata_link *link,
+				   unsigned long deadline, bool *online)
+{
+	const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context);
+	struct ata_port *ap = link->ap;
+	struct ahci_host_priv *hpriv = ap->host->private_data;
+	struct xgene_ahci_context *ctx = hpriv->plat_data;
+	struct ahci_port_priv *pp = ap->private_data;
+	u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
+	void __iomem *port_mmio = ahci_port_base(ap);
+	struct ata_taskfile tf;
+	int rc;
+	u32 val;
+
+	/* clear D2H reception area to properly wait for D2H FIS */
+	ata_tf_init(link->device, &tf);
+	tf.command = ATA_BUSY;
+	ata_tf_to_fis(&tf, 0, 0, d2h_fis);
+	rc = sata_link_hardreset(link, timing, deadline, online,
+				 ahci_check_ready);
+
+	val = readl(port_mmio + PORT_SCR_ERR);
+	if (val & (SERR_DISPARITY | SERR_10B_8B_ERR))
+		dev_warn(ctx->dev, "link has error\n");
+
+	/* clear all errors if any pending */
+	val = readl(port_mmio + PORT_SCR_ERR);
+	writel(val, port_mmio + PORT_SCR_ERR);
+
+	return rc;
+}
+
+static int xgene_ahci_hardreset(struct ata_link *link, unsigned int *class,
+				unsigned long deadline)
+{
+	struct ata_port *ap = link->ap;
+        struct ahci_host_priv *hpriv = ap->host->private_data;
+	void __iomem *port_mmio = ahci_port_base(ap);
+	bool online;
+	int rc;
+	u32 portcmd_saved;
+	u32 portclb_saved;
+	u32 portclbhi_saved;
+	u32 portrxfis_saved;
+	u32 portrxfishi_saved;
+
+	/* As hardreset resets these CSR, save it to restore later */
+	portcmd_saved = readl(port_mmio + PORT_CMD);
+	portclb_saved = readl(port_mmio + PORT_LST_ADDR);
+	portclbhi_saved = readl(port_mmio + PORT_LST_ADDR_HI);
+	portrxfis_saved = readl(port_mmio + PORT_FIS_ADDR);
+	portrxfishi_saved = readl(port_mmio + PORT_FIS_ADDR_HI);
+
+	ahci_stop_engine(ap);
+
+	rc = xgene_ahci_do_hardreset(link, deadline, &online);
+
+	/* As controller hardreset clears them, restore them */
+	writel(portcmd_saved, port_mmio + PORT_CMD);
+	writel(portclb_saved, port_mmio + PORT_LST_ADDR);
+	writel(portclbhi_saved, port_mmio + PORT_LST_ADDR_HI);
+	writel(portrxfis_saved, port_mmio + PORT_FIS_ADDR);
+	writel(portrxfishi_saved, port_mmio + PORT_FIS_ADDR_HI);
+
+	hpriv->start_engine(ap);
+
+	if (online)
+		*class = ahci_dev_classify(ap);
+
+	return rc;
+}
+
+static struct ata_port_operations xgene_ahci_ops = {
+	.inherits = &ahci_ops,
+	.hardreset = xgene_ahci_hardreset,
+	.read_id = xgene_ahci_read_id,
+};
+
+static const struct ata_port_info xgene_ahci_port_info = {
+	AHCI_HFLAGS(AHCI_HFLAG_NO_PMP | AHCI_HFLAG_YES_NCQ),
+	.flags = AHCI_FLAG_COMMON | ATA_FLAG_NCQ,
+	.pio_mask = ATA_PIO4,
+	.udma_mask = ATA_UDMA6,
+	.port_ops = &xgene_ahci_ops,
+};
+
+static int xgene_ahci_hw_init(struct ahci_host_priv *hpriv)
+{
+	struct xgene_ahci_context *ctx = hpriv->plat_data;
+	int i;
+	int rc;
+	u32 val;
+
+	/* Remove IP RAM out of shutdown */
+	rc = xgene_ahci_init_memram(ctx);
+	if (rc)
+		return rc;
+
+	for (i = 0; i < MAX_AHCI_CHN_PERCTR; i++)
+		xgene_ahci_set_phy_cfg(ctx, i);
+
+	/* AXI disable Mask */
+	writel(0xffffffff, hpriv->mmio + HOST_IRQ_STAT);
+	readl(hpriv->mmio + HOST_IRQ_STAT); /* Force a barrier */
+	writel(0, ctx->csr_base + INTSTATUSMASK);
+	readl(ctx->csr_base + INTSTATUSMASK); /* Force a barrier */
+	dev_dbg(ctx->dev, "top level interrupt mask 0x%X value 0x%08X\n",
+		INTSTATUSMASK, val);
+
+	writel(0x0, ctx->csr_base + ERRINTSTATUSMASK);
+	readl(ctx->csr_base + ERRINTSTATUSMASK); /* Force a barrier */
+	writel(0x0, ctx->csr_base + SATA_SHIM_OFFSET + INT_SLV_TMOMASK);
+	readl(ctx->csr_base + SATA_SHIM_OFFSET + INT_SLV_TMOMASK);
+
+	/* Enable AXI Interrupt */
+	writel(0xffffffff, ctx->csr_base + SLVRDERRATTRIBUTES);
+	writel(0xffffffff, ctx->csr_base + SLVWRERRATTRIBUTES);
+	writel(0xffffffff, ctx->csr_base + MSTRDERRATTRIBUTES);
+	writel(0xffffffff, ctx->csr_base + MSTWRERRATTRIBUTES);
+
+	/* Enable coherency */
+	val = readl(ctx->csr_base + BUSCTLREG);
+	val &= ~0x00000002;     /* Enable write coherency */
+	val &= ~0x00000001;     /* Enable read coherency */
+	writel(val, ctx->csr_base + BUSCTLREG);
+
+	val = readl(ctx->csr_base + IOFMSTRWAUX);
+	val |= (1 << 3);        /* Enable read coherency */
+	val |= (1 << 9);        /* Enable write coherency */
+	writel(val, ctx->csr_base + IOFMSTRWAUX);
+	val = readl(ctx->csr_base + IOFMSTRWAUX);
+	dev_dbg(ctx->dev, "coherency 0x%X value 0x%08X\n",
+		IOFMSTRWAUX, val);
+
+	return rc;
+}
+
+static int xgene_ahci_mux_select(struct xgene_ahci_context *ctx)
+{
+	void *mux_csr = ctx->csr_base + SATA_ENET_MUX_OFFSET;
+	u32 val;
+
+	val = readl(mux_csr + SATA_ENET_CONFIG_REG);
+	val &= ~CFG_SATA_ENET_SELECT_MASK;
+	writel(val, mux_csr + SATA_ENET_CONFIG_REG);
+	val = readl(mux_csr + SATA_ENET_CONFIG_REG);
+	return val & CFG_SATA_ENET_SELECT_MASK ? -1 : 0;
+}
+
+static int xgene_ahci_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ahci_host_priv *hpriv;
+	struct xgene_ahci_context *ctx;
+	struct resource *res;
+	int rc;
+
+	hpriv = ahci_platform_get_resources(pdev);
+	if (IS_ERR(hpriv))
+		return PTR_ERR(hpriv);
+
+	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx) {
+		dev_err(dev, "can't allocate host context\n");
+		return -ENOMEM;
+	}
+	hpriv->plat_data = ctx;
+	ctx->hpriv = hpriv;
+	ctx->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res) {
+		dev_err(dev, "no csr space\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Can't use devm_ioremap_resource due to overlapping region.
+	 * 0xYYYY.0000 - host core
+	 * 0xYYYY.7000 - Mux (if applicable)
+	 * 0xYYYY.A000 - PHY indirect access
+	 * 0xYYYY.C000 - Clock
+	 * 0xYYYY.D000 - RAM shutdown removal
+	 * As we map the entire region as one, it overlaps with the PHY driver.
+	 */
+	ctx->csr_base = devm_ioremap(dev, res->start, resource_size(res));
+	if (!ctx->csr_base) {
+		dev_err(dev, "can't map %pR\n", res);
+		return -ENOMEM;
+	}
+
+	dev_dbg(dev, "VAddr 0x%p Mmio VAddr 0x%p\n", ctx->csr_base,
+		hpriv->mmio);
+
+	/* Select ATA */
+	if (of_device_is_compatible(pdev->dev.of_node,
+		XGENE_AHCI_SGMII_DTS)) {
+		if (xgene_ahci_mux_select(ctx)) {
+			dev_err(dev, "SATA mux selection failed\n");
+			return -ENODEV;
+		}
+	}
+
+	/* Due to errata, HW requires full toggle transition */
+	rc = ahci_platform_enable_clks(hpriv);
+	if (rc)
+		goto disable_resources;
+	ahci_platform_disable_clks(hpriv);
+
+	rc = ahci_platform_enable_resources(hpriv);
+	if (rc)
+		goto disable_resources;
+
+	/* Configure the host controller */
+	xgene_ahci_hw_init(hpriv);
+
+	/* Setup DMA mask - 32 for 32-bit system and 64 for 64-bit system */
+	rc = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(8*sizeof(void *)));
+	if (rc) {
+		dev_err(dev, "Unable to set dma mask\n");
+		phy_exit(hpriv->phy);
+		goto disable_resources;
+	}
+
+	rc = ahci_platform_init_host(pdev, hpriv, &xgene_ahci_port_info, 0, 0);
+	if (rc) {
+		phy_exit(hpriv->phy);
+		goto disable_resources;
+	}
+
+	dev_dbg(dev, "X-Gene SATA host controller initialized\n");
+	return 0;
+
+disable_resources:
+	ahci_platform_disable_resources(hpriv);
+	return rc;
+}
+
+static const struct of_device_id xgene_ahci_of_match[] = {
+	{.compatible = XGENE_AHCI_SGMII_DTS,},
+	{.compatible = XGENE_AHCI_PCIE_DTS,},
+	{},
+};
+MODULE_DEVICE_TABLE(of, xgene_ahci_of_match);
+
+static struct platform_driver xgene_ahci_driver = {
+	.probe = xgene_ahci_probe,
+	.remove = ata_platform_remove_one,
+	.driver = {
+		.name = "xgene-ahci",
+		.owner = THIS_MODULE,
+		.of_match_table = xgene_ahci_of_match,
+	},
+};
+
+module_platform_driver(xgene_ahci_driver);
+
+MODULE_DESCRIPTION("APM X-Gene AHCI SATA driver");
+MODULE_AUTHOR("Loc Ho <lho@apm.com>");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.4");