[PATCH v3 0/3] ahci: add ports-implemented dt bindings

[PATCH v3 0/3] ahci: add ports-implemented dt bindings

[Srinivas Kandagatla]

Hi Tejun,

On some SOCs PORTS_IMPL register value is never programmed by the BIOS
and left at zero value. Which means that no sata ports are available for
software. AHCI driver used to cope up with this by fabricating the
port_map if the PORTS_IMPL register is read zero, but recent patch [1]
broke this workaround as zero value was valid for nvme disks.

This patch adds ports-implemented dt bindings as workaround for this issue
in a way that DT can dictate the port_map incase where the SOCs does not
program it already.

Am sure that there are more than one SOC that hits this issue.

Without this patchset, ACHI on APQ8064 Qualcomm platform is broken in mainline.
With the below patchset am able to get back the functionality.

Can you take all the patches via libata tree, I have collected the
acks required for DT.

Changes since v2:
	- reordered compatible strings in DT spotted by Sergei.

Changes since RFC:
	- Remove DT example as suggested by Rob.
	- Fixed comments on DT binding patch as suggested by Rob.
	- removed unused variable spotted by kernel test robot.

Thanks,
srini
[1] 566d18 "libata: disable forced PORTS_IMPL for >= AHCI 1.3"

Srinivas Kandagatla (3):
  libahci: save port map for forced port map
  ata: ahci-platform: Add ports-implemented DT bindings.
  ARM: dts: apq8064: add ahci ports-implemented mask

 Documentation/devicetree/bindings/ata/ahci-platform.txt | 4 ++++
 arch/arm/boot/dts/qcom-apq8064.dtsi                     | 3 ++-
 drivers/ata/ahci_platform.c                             | 3 +++
 drivers/ata/libahci.c                                   | 1 +
 4 files changed, 10 insertions(+), 1 deletion(-)

-- 
2.5.0

[PATCH v3 1/3] libahci: save port map for forced port map

[Srinivas Kandagatla]

In usecases where force_port_map is used saved_port_map is never set,
resulting in not programming the PORTS_IMPL register as part of initial
config. This patch fixes this by setting it to port_map even in case
where force_port_map is used, making it more inline with other parts of
the code.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Acked-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Reviewed-by: Andy Gross <andy.gross-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 drivers/ata/libahci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 3982054..a5d7c1c 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -507,6 +507,7 @@ void ahci_save_initial_config(struct device *dev, struct ahci_host_priv *hpriv)
 		dev_info(dev, "forcing port_map 0x%x -> 0x%x\n",
 			 port_map, hpriv->force_port_map);
 		port_map = hpriv->force_port_map;
+		hpriv->saved_port_map = port_map;
 	}
 
 	if (hpriv->mask_port_map) {
-- 
2.5.0

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[PATCH v3 2/3] ata: ahci-platform: Add ports-implemented DT bindings.

[Srinivas Kandagatla]

On some SOCs PORTS_IMPL register value is never programmed by the
firmware and left at zero value. Which means that no sata ports are
available for software. AHCI driver used to cope up with this by
fabricating the port_map if the PORTS_IMPL register is read zero,
but recent patch broke this workaround as zero value was valid for
NVMe disks.

This patch adds ports-implemented DT bindings as workaround for this issue
in a way that DT can can override the PORTS_IMPL register in cases where
the firmware did not program it already.

Fixes: 566d1827df2e ("libata: disable forced PORTS_IMPL for >= AHCI 1.3)
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
---
 Documentation/devicetree/bindings/ata/ahci-platform.txt | 4 ++++
 drivers/ata/ahci_platform.c                             | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/ata/ahci-platform.txt b/Documentation/devicetree/bindings/ata/ahci-platform.txt
index 30df832..87adfb2 100644
--- a/Documentation/devicetree/bindings/ata/ahci-platform.txt
+++ b/Documentation/devicetree/bindings/ata/ahci-platform.txt
@@ -32,6 +32,10 @@ Optional properties:
 - target-supply     : regulator for SATA target power
 - phys              : reference to the SATA PHY node
 - phy-names         : must be "sata-phy"
+- ports-implemented : Mask that indicates which ports that the HBA supports
+		      are available for software to use. Useful if PORTS_IMPL
+		      is not programmed by the BIOS, which is true with
+		      some embedded SOC's.
 
 Required properties when using sub-nodes:
 - #address-cells    : number of cells to encode an address
diff --git a/drivers/ata/ahci_platform.c b/drivers/ata/ahci_platform.c
index 4044233..62a04c8 100644
--- a/drivers/ata/ahci_platform.c
+++ b/drivers/ata/ahci_platform.c
@@ -51,6 +51,9 @@ static int ahci_probe(struct platform_device *pdev)
 	if (rc)
 		return rc;
 
+	of_property_read_u32(dev->of_node,
+			     "ports-implemented", &hpriv->force_port_map);
+
 	if (of_device_is_compatible(dev->of_node, "hisilicon,hisi-ahci"))
 		hpriv->flags |= AHCI_HFLAG_NO_FBS | AHCI_HFLAG_NO_NCQ;
 
-- 
2.5.0

Re: [PATCH v3 2/3] ata: ahci-platform: Add ports-implemented DT bindings.

[Rob Herring]

On Fri, Apr 01, 2016 at 08:52:57AM +0100, Srinivas Kandagatla wrote:
> On some SOCs PORTS_IMPL register value is never programmed by the
> firmware and left at zero value. Which means that no sata ports are
> available for software. AHCI driver used to cope up with this by
> fabricating the port_map if the PORTS_IMPL register is read zero,
> but recent patch broke this workaround as zero value was valid for
> NVMe disks.
> 
> This patch adds ports-implemented DT bindings as workaround for this issue
> in a way that DT can can override the PORTS_IMPL register in cases where
> the firmware did not program it already.
> 
> Fixes: 566d1827df2e ("libata: disable forced PORTS_IMPL for >= AHCI 1.3)
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> Acked-by: Tejun Heo <tj@kernel.org>
> Reviewed-by: Andy Gross <andy.gross@linaro.org>
> ---
>  Documentation/devicetree/bindings/ata/ahci-platform.txt | 4 ++++
>  drivers/ata/ahci_platform.c                             | 3 +++
>  2 files changed, 7 insertions(+)

Acked-by: Rob Herring <robh@kernel.org>

[PATCH v3 3/3] ARM: dts: apq8064: add ahci ports-implemented mask

[Srinivas Kandagatla]

This patch adds new ports-implemented mask, which is required to get
achi working on the mainline. Without this patch value read from
PORTS_IMPL register which is zero would not enable any ports for
software to use.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
---
 arch/arm/boot/dts/qcom-apq8064.dtsi | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/qcom-apq8064.dtsi b/arch/arm/boot/dts/qcom-apq8064.dtsi
index 252b310..36e058c 100644
--- a/arch/arm/boot/dts/qcom-apq8064.dtsi
+++ b/arch/arm/boot/dts/qcom-apq8064.dtsi
@@ -696,7 +696,7 @@
 		};
 
 		sata0: sata@29000000 {
-			compatible		= "generic-ahci";
+			compatible		= "qcom,apq8064-ahci", "generic-ahci";
 			status			= "disabled";
 			reg			= <0x29000000 0x180>;
 			interrupts		= <GIC_SPI 209 IRQ_TYPE_NONE>;
@@ -718,6 +718,7 @@
 
 			phys			= <&sata_phy0>;
 			phy-names		= "sata-phy";
+			ports-implemented	= <0x1>;
 		};
 
 		/* Temporary fixed regulator */
-- 
2.5.0

Re: [PATCH v3 0/3] ahci: add ports-implemented dt bindings

[Tejun Heo]

On Fri, Apr 01, 2016 at 08:52:55AM +0100, Srinivas Kandagatla wrote:
> On some SOCs PORTS_IMPL register value is never programmed by the BIOS
> and left at zero value. Which means that no sata ports are available for
> software. AHCI driver used to cope up with this by fabricating the
> port_map if the PORTS_IMPL register is read zero, but recent patch [1]
> broke this workaround as zero value was valid for nvme disks.
> 
> This patch adds ports-implemented dt bindings as workaround for this issue
> in a way that DT can dictate the port_map incase where the SOCs does not
> program it already.

Applied all three patches to libata/for-4.6-fixes w/ stable cc'd.

Thanks.

-- 
tejun