diff mbox

[v18,3/4] ata: Add APM X-Gene SoC AHCI SATA host controller driver

Message ID 1394841201-29495-4-git-send-email-lho@apm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Loc Ho March 14, 2014, 11:53 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 |  486 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 494 insertions(+), 0 deletions(-)
 create mode 100644 drivers/ata/ahci_xgene.c

Comments

Arnd Bergmann March 15, 2014, 9:19 a.m. UTC | #1
On Saturday 15 March 2014, 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.

This version seems workable, thanks for the quick follow-up.

The comment about Gen3 speed above reminds me that you took some
shortcuts to get here and you removed support for some features
as well as some bug workarounds in the process. I'm guessing some
of them won't be necessary because they are only for prototype
hardware or for early boot loader versions that don't yet set up
the hardware right, but others actually need to come back.

That is usually a good approach, but I'd also like to make sure we can
deal with them nicely when you have to add them back later, and don't
have to add ugly extensions to the DT binding to support the old dtb
files.

Can you list (also in the changelog) the parts of the driver that you
have taken out for now and that you expect to add back at later
stage? I think that would be helpful for perspective.

Regarding the support for multiple link speeds, how do you think
it will be done? Can you have a driver-side link speed autoconfiguration,
or do you have to add DT properties and let the driver know about
the attached device?

	Arnd
Loc Ho March 16, 2014, 6:17 a.m. UTC | #2
Hi,

>> 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.
>
> This version seems workable, thanks for the quick follow-up.
>
> The comment about Gen3 speed above reminds me that you took some
> shortcuts to get here and you removed support for some features
> as well as some bug workarounds in the process. I'm guessing some
> of them won't be necessary because they are only for prototype
> hardware or for early boot loader versions that don't yet set up
> the hardware right, but others actually need to come back.
>
> That is usually a good approach, but I'd also like to make sure we can
> deal with them nicely when you have to add them back later, and don't
> have to add ugly extensions to the DT binding to support the old dtb
> files.
>
> Can you list (also in the changelog) the parts of the driver that you
> have taken out for now and that you expect to add back at later
> stage? I think that would be helpful for perspective.
>

Here is an list of patches that we will be preparing for once the
basic driver is completed. Do you want me to re-generate the patch
change log with this info?

1. Support for Gen1/Gen2/Gen3
Solution: The simplest solution is to have the PHY framework support
setting the desire speed. I had argued with the TI folks but they are
reluctant to add this function to the framework. They argued that this
is still not generic enough. I will start the discussion again later
on. The other possibility (but not sure if this is doable) is to have
the PHY init function to be smarter and do the necessary operation
assuming the underlying PHY is capable in detecting the link up speed.
I will need to check the spec of this.

2. Retry COMRESET (hardreset) if failed first time
Solution: This code is purely in the host driver hardreset function.
It isn't for sure that we will need this. Given our current initial
board design, this seems to required 1 out of many, many power cycle
boot.

3. Cleaning the receiver line when SER_DISPARITY/SER_10B_8B error
during COMRESET (hardreset function call)
Solution: It is observed that during COMRESET, the receiver line can
report these errors and an clean up is required. For this, the code
will be with in the host driver and an call into the PHY layer. The
solution is the similar to #1 above.

4. IO flush before servicing completed operations (mostly read operations)
Solution: The read IO operations require an flush from the host
controller hardware side. For this, we will need to change the libahci
to call an function that is provided by the host driver if non-NULL.

5. PM (power management) support
Solution: Due to an errata in the host controller, stopping the
controller requires an slightly modified version in the way it detects
the host port completed the requested operation. For this we will have
to introduce an AHCI_HFLAG_XXX to detect the completion of FIS_RX
stopped by the CI register instead the PORT_CMD register or just delay
for 500ms.

> Regarding the support for multiple link speeds, how do you think
> it will be done?
> Can you have a driver-side link speed autoconfiguration,
> or do you have to add DT properties and let the driver know about
> the attached device?
>

See above #1.

-Loc
Loc Ho April 28, 2014, 11:12 p.m. UTC | #3
Hi Kishon/Felipe,

> >> 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.
> >
> > This version seems workable, thanks for the quick follow-up.
> >
> > The comment about Gen3 speed above reminds me that you took some
> > shortcuts to get here and you removed support for some features
> > as well as some bug workarounds in the process. I'm guessing some
> > of them won't be necessary because they are only for prototype
> > hardware or for early boot loader versions that don't yet set up
> > the hardware right, but others actually need to come back.
> >
> > That is usually a good approach, but I'd also like to make sure we can
> > deal with them nicely when you have to add them back later, and don't
> > have to add ugly extensions to the DT binding to support the old dtb
> > files.
> >
> > Can you list (also in the changelog) the parts of the driver that you
> > have taken out for now and that you expect to add back at later
> > stage? I think that would be helpful for perspective.
> >
>
> Here is an list of patches that we will be preparing for once the
> basic driver is completed. Do you want me to re-generate the patch
> change log with this info?
>
> 1. Support for Gen1/Gen2/Gen3
> Solution: The simplest solution is to have the PHY framework support
> setting the desire speed. I had argued with the TI folks but they are
> reluctant to add this function to the framework. They argued that this
> is still not generic enough. I will start the discussion again later
> on. The other possibility (but not sure if this is doable) is to have
> the PHY init function to be smarter and do the necessary operation
> assuming the underlying PHY is capable in detecting the link up speed.
> I will need to check the spec of this.


In order for the X-Gene SATA PHY to support SATA Gen1 and Gen2 speed,
we need an method to instruct the underlying PHY driver to switch to
an specified setting after link up. For this errata, Suman Tripathi
had submitted the patch [1]. It is not possible to hide this within
the PHY driver. Each instance of the PHY driver controls two ports. By
calling the exit function and then init function, it will affect the
other ports - which is not the correct behavior. At this point, we
don't see any solution besides introduce an PHY framework function
set_rate. Can you let us know if this solution is acceptable?

[1] https://lkml.org/lkml/2014/4/18/491

-Loc
Felipe Balbi April 28, 2014, 11:58 p.m. UTC | #4
On Mon, Apr 28, 2014 at 04:12:02PM -0700, Loc Ho wrote:
> Hi Kishon/Felipe,
> 
> > >> 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.
> > >
> > > This version seems workable, thanks for the quick follow-up.
> > >
> > > The comment about Gen3 speed above reminds me that you took some
> > > shortcuts to get here and you removed support for some features
> > > as well as some bug workarounds in the process. I'm guessing some
> > > of them won't be necessary because they are only for prototype
> > > hardware or for early boot loader versions that don't yet set up
> > > the hardware right, but others actually need to come back.
> > >
> > > That is usually a good approach, but I'd also like to make sure we can
> > > deal with them nicely when you have to add them back later, and don't
> > > have to add ugly extensions to the DT binding to support the old dtb
> > > files.
> > >
> > > Can you list (also in the changelog) the parts of the driver that you
> > > have taken out for now and that you expect to add back at later
> > > stage? I think that would be helpful for perspective.
> > >
> >
> > Here is an list of patches that we will be preparing for once the
> > basic driver is completed. Do you want me to re-generate the patch
> > change log with this info?
> >
> > 1. Support for Gen1/Gen2/Gen3
> > Solution: The simplest solution is to have the PHY framework support
> > setting the desire speed. I had argued with the TI folks but they are
> > reluctant to add this function to the framework. They argued that this
> > is still not generic enough. I will start the discussion again later
> > on. The other possibility (but not sure if this is doable) is to have
> > the PHY init function to be smarter and do the necessary operation
> > assuming the underlying PHY is capable in detecting the link up speed.
> > I will need to check the spec of this.
> 
> 
> In order for the X-Gene SATA PHY to support SATA Gen1 and Gen2 speed,
> we need an method to instruct the underlying PHY driver to switch to
> an specified setting after link up. For this errata, Suman Tripathi
> had submitted the patch [1]. It is not possible to hide this within
> the PHY driver. Each instance of the PHY driver controls two ports. By
> calling the exit function and then init function, it will affect the
> other ports - which is not the correct behavior. At this point, we
> don't see any solution besides introduce an PHY framework function
> set_rate. Can you let us know if this solution is acceptable?
> 
> [1] https://lkml.org/lkml/2014/4/18/491

that 'lane' argument isn't acceptable. If one PHY talks to two Links,
your PHY driver should register two providers, then the lane argument
can be ignored.

Rate can be reused for different things depending on the underlying Bus;
in case of USB, it could be for switching among
Superspeed10/Superspeed5Highspeed; or 1Gbit/100Mbit switch on Networking
interfaces; or Gen1/2/3 selection for PCI controllers and so on. The
only thing I can't find a way to abstract is that 'lane' argument which
isn't even specific to SATA, it's particular to how you guys wrote your
driver. Should you have one PHY per SATA link, you wouldn't have added
that 'lane' argument at all.

cheers
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..fcf21f1
--- /dev/null
+++ b/drivers/ata/ahci_xgene.c
@@ -0,0 +1,486 @@ 
+/*
+ * 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/>.
+ *
+ * NOTE: PM support is not currently available.
+ *
+ */
+#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"
+
+/* Max # of disk per a controller */
+#define MAX_AHCI_CHN_PERCTR		2
+
+/* MUX CSR */
+#define SATA_ENET_CONFIG_REG		0x00000000
+#define  CFG_SATA_ENET_SELECT_MASK	0x00000001
+
+/* SATA core 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 AXI CSR */
+#define INT_SLV_TMOMASK			0x00000010
+
+/* SATA 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_core;		/* Core CSR address of IP */
+	void __iomem *csr_diag;		/* Diag CSR address of IP */
+	void __iomem *csr_axi;		/* AXI CSR address of IP */
+	void __iomem *csr_mux;		/* MUX CSR address of IP */
+};
+
+static int xgene_ahci_init_memram(struct xgene_ahci_context *ctx)
+{
+	dev_dbg(ctx->dev, "Release memory from shutdown\n");
+	writel(0x0, ctx->csr_diag + CFG_MEM_RAM_SHUTDOWN);
+	readl(ctx->csr_diag + CFG_MEM_RAM_SHUTDOWN); /* Force a barrier */
+	msleep(1);	/* reset may take up to 1ms */
+	if (readl(ctx->csr_diag + 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: For the initial version, we will NOT support Gen1/Gen2. In addition
+ *       and until the underlying PHY supports an method to reset the receiver
+ *       line, on detection of SERR_DISPARITY or SERR_10B_8B_ERR errors,
+ *       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 void xgene_ahci_host_stop(struct ata_host *host)
+{
+	struct ahci_host_priv *hpriv = host->private_data;
+
+	ahci_platform_disable_resources(hpriv);
+}
+
+static struct ata_port_operations xgene_ahci_ops = {
+	.inherits = &ahci_ops,
+	.host_stop = xgene_ahci_host_stop,
+	.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_core + INTSTATUSMASK);
+	readl(ctx->csr_core + INTSTATUSMASK); /* Force a barrier */
+	dev_dbg(ctx->dev, "top level interrupt mask 0x%X value 0x%08X\n",
+		INTSTATUSMASK, val);
+
+	writel(0x0, ctx->csr_core + ERRINTSTATUSMASK);
+	readl(ctx->csr_core + ERRINTSTATUSMASK); /* Force a barrier */
+	writel(0x0, ctx->csr_axi + INT_SLV_TMOMASK);
+	readl(ctx->csr_axi + INT_SLV_TMOMASK);
+
+	/* Enable AXI Interrupt */
+	writel(0xffffffff, ctx->csr_core + SLVRDERRATTRIBUTES);
+	writel(0xffffffff, ctx->csr_core + SLVWRERRATTRIBUTES);
+	writel(0xffffffff, ctx->csr_core + MSTRDERRATTRIBUTES);
+	writel(0xffffffff, ctx->csr_core + MSTWRERRATTRIBUTES);
+
+	/* Enable coherency */
+	val = readl(ctx->csr_core + BUSCTLREG);
+	val &= ~0x00000002;     /* Enable write coherency */
+	val &= ~0x00000001;     /* Enable read coherency */
+	writel(val, ctx->csr_core + BUSCTLREG);
+
+	val = readl(ctx->csr_core + IOFMSTRWAUX);
+	val |= (1 << 3);        /* Enable read coherency */
+	val |= (1 << 9);        /* Enable write coherency */
+	writel(val, ctx->csr_core + IOFMSTRWAUX);
+	val = readl(ctx->csr_core + 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)
+{
+	u32 val;
+
+	/* Check for optional MUX resource */
+	if (IS_ERR(ctx->csr_mux))
+		return 0;
+
+	val = readl(ctx->csr_mux + SATA_ENET_CONFIG_REG);
+	val &= ~CFG_SATA_ENET_SELECT_MASK;
+	writel(val, ctx->csr_mux + SATA_ENET_CONFIG_REG);
+	val = readl(ctx->csr_mux + 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)
+		return -ENOMEM;
+
+	hpriv->plat_data = ctx;
+	ctx->hpriv = hpriv;
+	ctx->dev = dev;
+
+	/* Retrieve the IP core resource */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	ctx->csr_core = devm_ioremap_resource(dev, res);
+	if (IS_ERR(ctx->csr_core))
+		return PTR_ERR(ctx->csr_core);
+
+	/* Retrieve the IP diagnostic resource */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+	ctx->csr_diag = devm_ioremap_resource(dev, res);
+	if (IS_ERR(ctx->csr_diag))
+		return PTR_ERR(ctx->csr_diag);
+
+	/* Retrieve the IP AXI resource */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 3);
+	ctx->csr_axi = devm_ioremap_resource(dev, res);
+	if (IS_ERR(ctx->csr_axi))
+		return PTR_ERR(ctx->csr_axi);
+
+	/* Retrieve the optional IP mux resource */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 4);
+	ctx->csr_mux = devm_ioremap_resource(dev, res);
+
+	dev_dbg(dev, "VAddr 0x%p Mmio VAddr 0x%p\n", ctx->csr_core,
+		hpriv->mmio);
+
+	/* Select ATA */
+	if ((rc = xgene_ahci_mux_select(ctx))) {
+		dev_err(dev, "SATA mux selection failed error %d\n", rc);
+		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. This is preliminary until the DMA range is sorted
+	 * out.
+	 */
+	rc = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
+	if (rc) {
+		dev_err(dev, "Unable to set dma mask\n");
+		goto disable_resources;
+	}
+
+	rc = ahci_platform_init_host(pdev, hpriv, &xgene_ahci_port_info, 0, 0);
+	if (rc)
+		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 = "apm,xgene-ahci"},
+	{},
+};
+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");