Re: [PATCHv2 1/2] coresight: Do not default to CPU0 for missing CPU phandle

[Sai Prakash Ranjan]

Hello Suzuki,

On 6/21/2019 3:18 PM, Suzuki K Poulose wrote:
> Hi Sai,
>
>
> On 06/20/2019 07:31 PM, Sai Prakash Ranjan wrote:
> > Coresight platform support assumes that a missing "cpu" phandle
> > defaults to CPU0. This could be problematic and unnecessarily binds
> > components to CPU0, where they may not be. Let us make the DT binding
> > rules a bit stricter by not defaulting to CPU0 for missing "cpu"
> > affinity information.
> >
> > Also in coresight etm and cpu-debug drivers, abort the probe
> > for such cases.
> >
> > Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
> > Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
>
> Please drop this tag for now.

Ok will drop this.

> > ---
> > Â Documentation/devicetree/bindings/arm/coresight.txt |Â 2 +-
> > Â drivers/hwtracing/coresight/coresight-cpu-debug.cÂÂ |Â 3 +++
> > Â drivers/hwtracing/coresight/coresight-etm3x.cÂÂÂÂÂÂ |Â 3 +++
> > Â drivers/hwtracing/coresight/coresight-etm4x.cÂÂÂÂÂÂ |Â 3 +++
> > Â drivers/hwtracing/coresight/coresight-platform.cÂÂÂ | 10 +++++-----
> > Â 5 files changed, 15 insertions(+), 6 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/arm/coresight.txt 
> > b/Documentation/devicetree/bindings/arm/coresight.txt
> > index 8a88ddebc1a2..c4659ba9457d 100644
> > --- a/Documentation/devicetree/bindings/arm/coresight.txt
> > +++ b/Documentation/devicetree/bindings/arm/coresight.txt
> > @@ -88,7 +88,7 @@ its hardware characteristcs.
> > ÂÂÂÂÂÂÂ registers via co-processor 14.
> > ÂÂÂÂÂ * cpu: the cpu phandle this ETM/PTM is affined to. When omitted the
> > -ÂÂÂÂÂ source is considered to belong to CPU0.
> > +ÂÂÂÂÂ affinity is set to invalid.
>
> Please move this from the "Optional properties". It is not "Optional"
> anymore with this change. Please make sure it is evident that this
> is mandatory. Also please fix the bindings document for cpu-debug.txt.
>
>
> > Â * Optional property for TMC:
>
> > diff --git a/drivers/hwtracing/coresight/coresight-platform.c 
> > b/drivers/hwtracing/coresight/coresight-platform.c
> > index 3c5ceda8db24..8b03fa573684 100644
> > --- a/drivers/hwtracing/coresight/coresight-platform.c
> > +++ b/drivers/hwtracing/coresight/coresight-platform.c
> > @@ -159,16 +159,16 @@ static int of_coresight_get_cpu(struct device *dev)
> > ÂÂÂÂÂ struct device_node *dn;
> > ÂÂÂÂÂ if (!dev->of_node)
> > -ÂÂÂÂÂÂÂ return 0;
> > +ÂÂÂÂÂÂÂ return -ENODEV;
> > +
> > ÂÂÂÂÂ dn = of_parse_phandle(dev->of_node, "cpu", 0);
> > -ÂÂÂ /* Affinity defaults to CPU0 */
> > ÂÂÂÂÂ if (!dn)
> > -ÂÂÂÂÂÂÂ return 0;
> > +ÂÂÂÂÂÂÂ return -ENODEV;
> > +
> > ÂÂÂÂÂ cpu = of_cpu_node_to_id(dn);
> > ÂÂÂÂÂ of_node_put(dn);
>
> Please fix the acpi_coresight_get_cpu() for ACPI.

Ok will do it. Thanks again for the review comments.

-Sai

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