tree e5219e173278994cc4dc42e941237abafe16bf88
parent 2fd0f46cb1b82587c7ae4a616d69057fb9bd0af7
author Srinivas Kandagatla <srinivas.kandagatla@linaro.org> 1459497177 +0100
committer Tejun Heo <tj@kernel.org> 1459521030 -0400

ata: ahci-platform: Add ports-implemented DT bindings.

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")
Cc: stable@vger.kernel.org # v4.5+
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Tejun Heo <tj@kernel.org>