diff mbox

[v8,1/3] Documentation/devicetree: Add new property to specify the max link speed

Message ID 1476755110-22647-1-git-send-email-shawn.lin@rock-chips.com (mailing list archive)
State New, archived
Headers show

Commit Message

Shawn Lin Oct. 18, 2016, 1:45 a.m. UTC
Some of the host drivers have the requirement of knowing whether the
EP would never train at some link speed at all. For instance, on some
boards, the link won't train at 5 GT/s but the host driver still sacrifice
some cycle to wait for the resule of training at 5 GT/s as the host could
actually support 5 GT/s. So we could parse this new property and make the
host drivers be aware of these cases.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
---

Changes in v8: None
Changes in v7: None
Changes in v6: None
Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2: None

 Documentation/devicetree/bindings/pci/pci.txt | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Rob Herring Oct. 18, 2016, 4:41 p.m. UTC | #1
On Tue, Oct 18, 2016 at 09:45:08AM +0800, Shawn Lin wrote:
> Some of the host drivers have the requirement of knowing whether the
> EP would never train at some link speed at all. For instance, on some
> boards, the link won't train at 5 GT/s but the host driver still sacrifice
> some cycle to wait for the resule of training at 5 GT/s as the host could
> actually support 5 GT/s. So we could parse this new property and make the
> host drivers be aware of these cases.
> 
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> ---
> 
> Changes in v8: None
> Changes in v7: None
> Changes in v6: None
> Changes in v5: None
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None

Humm, either you are respinning versions too quickly or failed to copy 
the DT list.

> 
>  Documentation/devicetree/bindings/pci/pci.txt | 6 ++++++
>  1 file changed, 6 insertions(+)

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

> 
> diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt
> index 08dcfad..e7d97a3 100644
> --- a/Documentation/devicetree/bindings/pci/pci.txt
> +++ b/Documentation/devicetree/bindings/pci/pci.txt
> @@ -18,3 +18,9 @@ driver implementation may support the following properties:
>     host bridges in the system, otherwise potentially conflicting domain numbers
>     may be assigned to root buses behind different host bridges.  The domain
>     number for each host bridge in the system must be unique.
> +- max-link-speed:
> +   If present this property specifies PCI gen for link capability. The host drivers
> +   could add this as a strategy to avoid unnecessary operation for unsupported
> +   link speed, for instance, trying to do training for unsupported link speed, etc.
> +   Must be '4' for gen4, '3' for gen3, '2' for gen2, and '1' for gen1. Any other
> +   values are invalid.
> -- 
> 2.3.7
> 
>
Bjorn Helgaas Nov. 11, 2016, 10:24 p.m. UTC | #2
On Tue, Oct 18, 2016 at 09:45:08AM +0800, Shawn Lin wrote:
> Some of the host drivers have the requirement of knowing whether the
> EP would never train at some link speed at all. For instance, on some
> boards, the link won't train at 5 GT/s but the host driver still sacrifice
> some cycle to wait for the resule of training at 5 GT/s as the host could
> actually support 5 GT/s. So we could parse this new property and make the
> host drivers be aware of these cases.
> 
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

Applied all three, with Rob's acks on the first two, to pci/host-rockchip
for v4.10, thanks!

> ---
> 
> Changes in v8: None
> Changes in v7: None
> Changes in v6: None
> Changes in v5: None
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None
> 
>  Documentation/devicetree/bindings/pci/pci.txt | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt
> index 08dcfad..e7d97a3 100644
> --- a/Documentation/devicetree/bindings/pci/pci.txt
> +++ b/Documentation/devicetree/bindings/pci/pci.txt
> @@ -18,3 +18,9 @@ driver implementation may support the following properties:
>     host bridges in the system, otherwise potentially conflicting domain numbers
>     may be assigned to root buses behind different host bridges.  The domain
>     number for each host bridge in the system must be unique.
> +- max-link-speed:
> +   If present this property specifies PCI gen for link capability. The host drivers
> +   could add this as a strategy to avoid unnecessary operation for unsupported
> +   link speed, for instance, trying to do training for unsupported link speed, etc.
> +   Must be '4' for gen4, '3' for gen3, '2' for gen2, and '1' for gen1. Any other
> +   values are invalid.
> -- 
> 2.3.7
> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/pci/pci.txt b/Documentation/devicetree/bindings/pci/pci.txt
index 08dcfad..e7d97a3 100644
--- a/Documentation/devicetree/bindings/pci/pci.txt
+++ b/Documentation/devicetree/bindings/pci/pci.txt
@@ -18,3 +18,9 @@  driver implementation may support the following properties:
    host bridges in the system, otherwise potentially conflicting domain numbers
    may be assigned to root buses behind different host bridges.  The domain
    number for each host bridge in the system must be unique.
+- max-link-speed:
+   If present this property specifies PCI gen for link capability. The host drivers
+   could add this as a strategy to avoid unnecessary operation for unsupported
+   link speed, for instance, trying to do training for unsupported link speed, etc.
+   Must be '4' for gen4, '3' for gen3, '2' for gen2, and '1' for gen1. Any other
+   values are invalid.