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

Message ID 1459497178-31090-3-git-send-email-srinivas.kandagatla@linaro.org
State Accepted
Commit 17dcc37e3e847bc0e67a5b1ec52471fcc6c18682
Headers show

Commit Message

Srinivas Kandagatla April 1, 2016, 7:52 a.m. UTC 
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(+)

-- 
2.5.0
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Patch

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;