diff mbox

[v2,2/2] Documentation: dt-bindings: Add option to workaround STE.VALID in Broadcom Vulcan

Message ID 1450346376-30920-2-git-send-email-pmallapp@broadcom.com (mailing list archive)
State New, archived
Headers show

Commit Message

pmallapp@broadcom.com Dec. 17, 2015, 9:59 a.m. UTC
Signed-off-by: Prem Mallappa <pmallapp@broadcom.com>
---
 Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Will Deacon Dec. 17, 2015, 11:51 a.m. UTC | #1
[adding devicetree since I'd like an Ack from them if possible]

On Thu, Dec 17, 2015 at 03:29:36PM +0530, Prem Mallappa wrote:
> Signed-off-by: Prem Mallappa <pmallapp@broadcom.com>

Please can you add a commit message for this?

> ---
>  Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
> index 947863a..9c1218e 100644
> --- a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
> @@ -43,6 +43,11 @@ the PCIe specification.
>  - hisilicon,broken-prefetch-cmd
>                      : Avoid sending CMD_PREFETCH_* commands to the SMMU.
>  
> +- broadcom,broken-ste-valid-check
> +                    : Broadcom specific, h/w peeks into more than just 
> +		      STE.VALID bit in "Bypass" mode. Enabling this, 
> +		      populates needed bits.

This should really describe more about what happens, I think. For example,

"Enable ATS and Stage-2 AArch64 translation in bypass STEs, since some
 hardware requires this in order for an STE to be treated as valid."

Will
Mark Rutland Dec. 17, 2015, noon UTC | #2
On Thu, Dec 17, 2015 at 11:51:03AM +0000, Will Deacon wrote:
> [adding devicetree since I'd like an Ack from them if possible]
> 
> On Thu, Dec 17, 2015 at 03:29:36PM +0530, Prem Mallappa wrote:
> > Signed-off-by: Prem Mallappa <pmallapp@broadcom.com>
> 
> Please can you add a commit message for this?
> 
> > ---
> >  Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
> > index 947863a..9c1218e 100644
> > --- a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
> > +++ b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
> > @@ -43,6 +43,11 @@ the PCIe specification.
> >  - hisilicon,broken-prefetch-cmd
> >                      : Avoid sending CMD_PREFETCH_* commands to the SMMU.
> >  
> > +- broadcom,broken-ste-valid-check
> > +                    : Broadcom specific, h/w peeks into more than just 
> > +		      STE.VALID bit in "Bypass" mode. Enabling this, 
> > +		      populates needed bits.
> 
> This should really describe more about what happens, I think. For example,
> 
> "Enable ATS and Stage-2 AArch64 translation in bypass STEs, since some
>  hardware requires this in order for an STE to be treated as valid."

We certainly need to define the "needed bits".

Assuming your example cover all of those, it sounds fine to me.

Mark.
diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
index 947863a..9c1218e 100644
--- a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
+++ b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.txt
@@ -43,6 +43,11 @@  the PCIe specification.
 - hisilicon,broken-prefetch-cmd
                     : Avoid sending CMD_PREFETCH_* commands to the SMMU.
 
+- broadcom,broken-ste-valid-check
+                    : Broadcom specific, h/w peeks into more than just 
+		      STE.VALID bit in "Bypass" mode. Enabling this, 
+		      populates needed bits.
+
 ** Example
 
         smmu@2b400000 {