diff mbox

[v17,3/4] ata: Add APM X-Gene SoC AHCI SATA host controller driver

Message ID 1394655573-32645-4-git-send-email-lho@apm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Loc Ho March 12, 2014, 8:19 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 |  497 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 505 insertions(+), 0 deletions(-)
 create mode 100644 drivers/ata/ahci_xgene.c

Comments

Bartlomiej Zolnierkiewicz March 13, 2014, 5:01 p.m. UTC | #1
On Wednesday, March 12, 2014 02:19:32 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>

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

Thanks for fixing all the remaining issues.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
Arnd Bergmann March 14, 2014, 11:41 a.m. UTC | #2
On Wednesday 12 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.
> 
> Signed-off-by: Loc Ho <lho@apm.com>
> Signed-off-by: Tuan Phan <tphan@apm.com>
> Signed-off-by: Suman Tripathi <stripathi@apm.com>

Sorry I've skipped the last ten review rounds. I'm glad to see the
code has improved so much in the meantime!

I hope the points I'm making here were not already covered in the
many previous review rounds.

> +/* 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"

Please remove these macros, they don't help anything at all
but make it harder to follow what's going on.

Regarding the actual strings, reflecting them now I think listing 'pcie'
and 'sgmii' is not really helpful to the reader. The difference to
the AHCI driver should not be which device it's sharing its PHY with,
but rather how that looks from software side.

The only difference in your current driver is whether this function

+/* MUX CSR */
+#define SATA_ENET_CONFIG_REG           0x00000000
+#define  CFG_SATA_ENET_SELECT_MASK     0x00000001
+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;
+}

gets called. Can you clarify what this register access does?
If it's just setting a index into a mux output, would it make
sense to have an optional DT property containing an integer with
the mux setting you want to set? That way you wouldn't even
have to have two compatible strings but just do

	ret = of_property_read_u32(node, "apm,ahci-mux", &mux);
	if (!ret)
		xgene_ahci_mux_select(ctx, mux);

> +	/*
> +	 * 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;
> +	}

I still think we should try not to have overlapping memory areas here.
Could you split up the registers into another range in the reg property
to leave the PHY registers out?

> +	/* 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");
> +		goto disable_resources;
> +	}

This is something we definitely have to fix properly. We are hitting
the problem of dma masks for internal devices on arm32 now, and there
is ongoing discussion about whether a device driver should touch these
at all, or rather rely on the DT core to set up the masks in a generic
way. This device is probably the first DMA master capable device we
have on arm64, other than PCI devices, and we must be careful to get it
right.

In either way, the mask of the device must *not* depend on sizeof(void*):
If the device is capable of doing 64-bit DMA, it should also be able
to do that when running a 32-bit kernel.

Please change this to DMA_BIT_MASK(64) for now, and add a comment
explaining that it is preliminary.

Also, please read the thread named "[PATCH 0/7] of: setup dma
parameters using dma-ranges and dma-coherent" and comment there
about what you think we should do here. I assume we will have to
add "dma-ranges" properties in a number of places to get this
all to work fine any 64-bit SoC. Do you know if you have any
DMA master devices in x-gene that are not 64-bit capable?

	Arnd
Loc Ho March 14, 2014, 6:49 p.m. UTC | #3
Hi,

> On Wednesday 12 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.
> >
> > Signed-off-by: Loc Ho <lho@apm.com>
> > Signed-off-by: Tuan Phan <tphan@apm.com>
> > Signed-off-by: Suman Tripathi <stripathi@apm.com>
>
> Sorry I've skipped the last ten review rounds. I'm glad to see the
> code has improved so much in the meantime!
>
> I hope the points I'm making here were not already covered in the
> many previous review rounds.
>
> > +/* 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"
>
> Please remove these macros, they don't help anything at all
> but make it harder to follow what's going on.
>
> Regarding the actual strings, reflecting them now I think listing 'pcie'
> and 'sgmii' is not really helpful to the reader. The difference to
> the AHCI driver should not be which device it's sharing its PHY with,
> but rather how that looks from software side.
>
> The only difference in your current driver is whether this function
>
> +/* MUX CSR */
> +#define SATA_ENET_CONFIG_REG           0x00000000
> +#define  CFG_SATA_ENET_SELECT_MASK     0x00000001
> +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;
> +}
>
> gets called. Can you clarify what this register access does?
> If it's just setting a index into a mux output, would it make
> sense to have an optional DT property containing an integer with
> the mux setting you want to set? That way you wouldn't even
> have to have two compatible strings but just do
>
>         ret = of_property_read_u32(node, "apm,ahci-mux", &mux);
>         if (!ret)
>                 xgene_ahci_mux_select(ctx, mux);
>

Given that fact that I will break up the resource. Let's just use the
resource for the MUX to handle this. For the IP that doesn't existed,
I will just not list it.


> > +     /*
> > +      * 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;
> > +     }
>
> I still think we should try not to have overlapping memory areas here.
> Could you split up the registers into another range in the reg property
> to leave the PHY registers out?

Let me do this:

1. One resource for the RAM shutdown
2. One resource for the host controller
3. One optional resource for the MUX if needed.

With #3, this also solved the MUX detection and avoid having another
node "apm,ahci-mux".

>
> > +     /* 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");
> > +             goto disable_resources;
> > +     }
>
> This is something we definitely have to fix properly. We are hitting
> the problem of dma masks for internal devices on arm32 now, and there
> is ongoing discussion about whether a device driver should touch these
> at all, or rather rely on the DT core to set up the masks in a generic
> way. This device is probably the first DMA master capable device we
> have on arm64, other than PCI devices, and we must be careful to get it
> right.
>
> In either way, the mask of the device must *not* depend on sizeof(void*):
> If the device is capable of doing 64-bit DMA, it should also be able
> to do that when running a 32-bit kernel.
>
> Please change this to DMA_BIT_MASK(64) for now, and add a comment
> explaining that it is preliminary.

okay.

>
> Also, please read the thread named "[PATCH 0/7] of: setup dma
> parameters using dma-ranges and dma-coherent" and comment there
> about what you think we should do here. I assume we will have to
> add "dma-ranges" properties in a number of places to get this
> all to work fine any 64-bit SoC. Do you know if you have any
> DMA master devices in x-gene that are not 64-bit capable?
>

I will read and follow later. We do have non-64-bit devices such as
SDIO and SPI. But these IP's have translation in the bus similar to
PCIe PIM.

-Loc
Arnd Bergmann March 14, 2014, 7:05 p.m. UTC | #4
On Friday 14 March 2014, Loc Ho wrote:
> > On Wednesday 12 March 2014, Loc Ho wrote:

> > gets called. Can you clarify what this register access does?
> > If it's just setting a index into a mux output, would it make
> > sense to have an optional DT property containing an integer with
> > the mux setting you want to set? That way you wouldn't even
> > have to have two compatible strings but just do
> >
> >         ret = of_property_read_u32(node, "apm,ahci-mux", &mux);
> >         if (!ret)
> >                 xgene_ahci_mux_select(ctx, mux);
> >
> 
> Given that fact that I will break up the resource. Let's just use the
> resource for the MUX to handle this. For the IP that doesn't existed,
> I will just not list it.

Ah, that sounds good. It also means that if the firmware has set up
the mux already, you don't have to touch it again. That would probably
be the preferred case.

I'm undecided about the value that you write in there. That could either
be passed through DT as I suggested above for extra flexibility, or you
can keep it hardcoded if you are absolutely sure that there will never
need to be a case where you have to set it to something other than '1',

> > > +     /*
> > > +      * 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;
> > > +     }
> >
> > I still think we should try not to have overlapping memory areas here.
> > Could you split up the registers into another range in the reg property
> > to leave the PHY registers out?
> 
> Let me do this:
> 
> 1. One resource for the RAM shutdown
> 2. One resource for the host controller
> 3. One optional resource for the MUX if needed.
> 
> With #3, this also solved the MUX detection and avoid having another
> node "apm,ahci-mux".

My suggestion was not to have another device node, just a property that
contains a value to be written into the mux register if present.

> > Also, please read the thread named "[PATCH 0/7] of: setup dma
> > parameters using dma-ranges and dma-coherent" and comment there
> > about what you think we should do here. I assume we will have to
> > add "dma-ranges" properties in a number of places to get this
> > all to work fine any 64-bit SoC. Do you know if you have any
> > DMA master devices in x-gene that are not 64-bit capable?
> >
> 
> I will read and follow later. We do have non-64-bit devices such as
> SDIO and SPI. But these IP's have translation in the bus similar to
> PCIe PIM.

Is there also an IOMMU, or just the PIM? If there is no IOMMU,
we will actually have to use the swiotlb code here, otherwise we
can rely on the IOMMU to do the translation so we can pretend that
there is always 64-bit DMA capability.

In theory, the PIM could be dynamically reprogrammed for each
DMA, as an extremely primitive IOMMU implementation, but I don't
know what the impact on performance would be from doing that.
It would also prevent you from starting multiple concurrent DMAs,
although I suspect that is not an important case for SPI and SDIO.

	Arnd
Loc Ho March 14, 2014, 8:27 p.m. UTC | #5
Hi,

>> > gets called. Can you clarify what this register access does?
>> > If it's just setting a index into a mux output, would it make
>> > sense to have an optional DT property containing an integer with
>> > the mux setting you want to set? That way you wouldn't even
>> > have to have two compatible strings but just do
>> >
>> >         ret = of_property_read_u32(node, "apm,ahci-mux", &mux);
>> >         if (!ret)
>> >                 xgene_ahci_mux_select(ctx, mux);
>> >
>>
>> Given that fact that I will break up the resource. Let's just use the
>> resource for the MUX to handle this. For the IP that doesn't existed,
>> I will just not list it.
>
> Ah, that sounds good. It also means that if the firmware has set up
> the mux already, you don't have to touch it again. That would probably
> be the preferred case.
>
> I'm undecided about the value that you write in there. That could either
> be passed through DT as I suggested above for extra flexibility, or you
> can keep it hardcoded if you are absolutely sure that there will never
> need to be a case where you have to set it to something other than '1',

It is only a mux between two IP's. Writing 1 is fine. For ACPI, it can
be missing and handled by the firmware or can be handled just like the
DTS way.

>
>> > > +     /*
>> > > +      * 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;
>> > > +     }
>> >
>> > I still think we should try not to have overlapping memory areas here.
>> > Could you split up the registers into another range in the reg property
>> > to leave the PHY registers out?
>>
>> Let me do this:
>>
>> 1. One resource for the RAM shutdown
>> 2. One resource for the host controller
>> 3. One optional resource for the MUX if needed.
>>
>> With #3, this also solved the MUX detection and avoid having another
>> node "apm,ahci-mux".
>
> My suggestion was not to have another device node, just a property that
> contains a value to be written into the mux register if present.
>
>> > Also, please read the thread named "[PATCH 0/7] of: setup dma
>> > parameters using dma-ranges and dma-coherent" and comment there
>> > about what you think we should do here. I assume we will have to
>> > add "dma-ranges" properties in a number of places to get this
>> > all to work fine any 64-bit SoC. Do you know if you have any
>> > DMA master devices in x-gene that are not 64-bit capable?
>> >
>>
>> I will read and follow later. We do have non-64-bit devices such as
>> SDIO and SPI. But these IP's have translation in the bus similar to
>> PCIe PIM.
>
> Is there also an IOMMU, or just the PIM? If there is no IOMMU,
> we will actually have to use the swiotlb code here, otherwise we
> can rely on the IOMMU to do the translation so we can pretend that
> there is always 64-bit DMA capability.
>
> In theory, the PIM could be dynamically reprogrammed for each
> DMA, as an extremely primitive IOMMU implementation, but I don't
> know what the impact on performance would be from doing that.
> It would also prevent you from starting multiple concurrent DMAs,
> although I suspect that is not an important case for SPI and SDIO.

This first generation don't support IOMMU and rely on swiotlb. In any
case, for SDIO, the solution is to reprogram the PIM and limit to SDMA
- single buffer - for each operation.

-Loc
Arnd Bergmann March 14, 2014, 9:06 p.m. UTC | #6
On Friday 14 March 2014, Loc Ho wrote:
> Hi,
> 
> >> > gets called. Can you clarify what this register access does?
> >> > If it's just setting a index into a mux output, would it make
> >> > sense to have an optional DT property containing an integer with
> >> > the mux setting you want to set? That way you wouldn't even
> >> > have to have two compatible strings but just do
> >> >
> >> >         ret = of_property_read_u32(node, "apm,ahci-mux", &mux);
> >> >         if (!ret)
> >> >                 xgene_ahci_mux_select(ctx, mux);
> >> >
> >>
> >> Given that fact that I will break up the resource. Let's just use the
> >> resource for the MUX to handle this. For the IP that doesn't existed,
> >> I will just not list it.
> >
> > Ah, that sounds good. It also means that if the firmware has set up
> > the mux already, you don't have to touch it again. That would probably
> > be the preferred case.
> >
> > I'm undecided about the value that you write in there. That could either
> > be passed through DT as I suggested above for extra flexibility, or you
> > can keep it hardcoded if you are absolutely sure that there will never
> > need to be a case where you have to set it to something other than '1',
> 
> It is only a mux between two IP's. Writing 1 is fine. For ACPI, it can
> be missing and handled by the firmware or can be handled just like the
> DTS way.

Why can't you have it handled by the firmware in the DTS case?

I still think it's rather unlikely that we will actually see ACPI support
on your platform, btw.

I'm willing to look at the patches you need for it, but I'm not very
optimistic, in particular because of the kind of hacks you need
for random bits of hardware.

> > Is there also an IOMMU, or just the PIM? If there is no IOMMU,
> > we will actually have to use the swiotlb code here, otherwise we
> > can rely on the IOMMU to do the translation so we can pretend that
> > there is always 64-bit DMA capability.
> >
> > In theory, the PIM could be dynamically reprogrammed for each
> > DMA, as an extremely primitive IOMMU implementation, but I don't
> > know what the impact on performance would be from doing that.
> > It would also prevent you from starting multiple concurrent DMAs,
> > although I suspect that is not an important case for SPI and SDIO.
> 
> This first generation don't support IOMMU and rely on swiotlb. In any
> case, for SDIO, the solution is to reprogram the PIM and limit to SDMA
> - single buffer - for each operation.

Ok, interesting. In that case, I suppose the DMA mask is actually 64-bit.

	Arnd
Loc Ho March 14, 2014, 9:38 p.m. UTC | #7
Hi

>> >> > gets called. Can you clarify what this register access does?
>> >> > If it's just setting a index into a mux output, would it make
>> >> > sense to have an optional DT property containing an integer with
>> >> > the mux setting you want to set? That way you wouldn't even
>> >> > have to have two compatible strings but just do
>> >> >
>> >> >         ret = of_property_read_u32(node, "apm,ahci-mux", &mux);
>> >> >         if (!ret)
>> >> >                 xgene_ahci_mux_select(ctx, mux);
>> >> >
>> >>
>> >> Given that fact that I will break up the resource. Let's just use the
>> >> resource for the MUX to handle this. For the IP that doesn't existed,
>> >> I will just not list it.
>> >
>> > Ah, that sounds good. It also means that if the firmware has set up
>> > the mux already, you don't have to touch it again. That would probably
>> > be the preferred case.
>> >
>> > I'm undecided about the value that you write in there. That could either
>> > be passed through DT as I suggested above for extra flexibility, or you
>> > can keep it hardcoded if you are absolutely sure that there will never
>> > need to be a case where you have to set it to something other than '1',
>>
>> It is only a mux between two IP's. Writing 1 is fine. For ACPI, it can
>> be missing and handled by the firmware or can be handled just like the
>> DTS way.
>
> Why can't you have it handled by the firmware in the DTS case?
>
> I still think it's rather unlikely that we will actually see ACPI support
> on your platform, btw.
>
> I'm willing to look at the patches you need for it, but I'm not very
> optimistic, in particular because of the kind of hacks you need
> for random bits of hardware.
>

I am about to post another version. Can you look at the next version?
If you still think it needs to be moved to the FW (either U-Boot or
Tianocore UEFI boot loader), I will then move out of the Linux driver
code.

-Loc
Arnd Bergmann March 15, 2014, 9:01 a.m. UTC | #8
On Friday 14 March 2014, Loc Ho wrote:

> > I still think it's rather unlikely that we will actually see ACPI support
> > on your platform, btw.
> >
> > I'm willing to look at the patches you need for it, but I'm not very
> > optimistic, in particular because of the kind of hacks you need
> > for random bits of hardware.
> >
> 
> I am about to post another version. Can you look at the next version?
> If you still think it needs to be moved to the FW (either U-Boot or
> Tianocore UEFI boot loader), I will then move out of the Linux driver
> code.

I would certainly be happier if it could just be moved into the
firmware or boot loader all the time. The only times we actually
want to do this stuff in the kernel is when we can't trust the
boot loader to get it right, or when the kernel has to support
alternative configurations that the boot loader is not aware of,
e.g. when you can plug in different kinds of extension boards but
the boot loader doesn't know which one you have.

	Arnd
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..e0e637a
--- /dev/null
+++ b/drivers/ata/ahci_xgene.c
@@ -0,0 +1,497 @@ 
+/*
+ * 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"
+
+/* 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 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_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");
+		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 = 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");