On Aug 16, 2013, at 5:31 AM, Punit Agrawal wrote: > On 15/08/13 17:25, Kumar Gala wrote: >> >> On Aug 15, 2013, at 4:10 AM, Punit Agrawal wrote: >> >>> Hi Kumar, >>> >>> Thanks for a review of the bindings. >>> >>> On 14/08/13 22:03, Kumar Gala wrote: >>>> >>>> On Jul 23, 2013, at 4:19 AM, Punit Agrawal wrote: >>>> >>>>> The CCI PMU can profile bus transactions at the master and slave >>>>> interfaces of the CCI. The PMU can be used to observe an aggregated view >>>>> of the bus traffic between the various components connected to the CCI. >>>>> >>>>> Extend the existing CCI driver to support the PMU by registering a perf >>>>> backend for it. >>>>> >>>>> Document the device tree binding to describe the CCI PMU. >>>>> >>>>> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> >>>>> Cc: Nicolas Pitre <nico@xxxxxxxxxx> >>>>> Cc: Dave Martin <dave.martin@xxxxxxxxxx> >>>>> Cc: Rob Herring <rob.herring@xxxxxxxxxxx> >>>>> Cc: Will Deacon <will.deacon@xxxxxxx> >>>>> Signed-off-by: Punit Agrawal <punit.agrawal@xxxxxxx> >>>>> Reviewed-by: Will Deacon <will.deacon@xxxxxxx> >>>>> --- >>>>> Documentation/devicetree/bindings/arm/cci.txt | 38 ++ >>>>> drivers/bus/arm-cci.c | 642 +++++++++++++++++++++++++ >>>>> 2 files changed, 680 insertions(+) >>>>> >>>>> diff --git a/Documentation/devicetree/bindings/arm/cci.txt b/Documentation/devicetree/bindings/arm/cci.txt >>>>> index 92d36e2..5bc95e5 100644 >>>>> --- a/Documentation/devicetree/bindings/arm/cci.txt >>>>> +++ b/Documentation/devicetree/bindings/arm/cci.txt >>>>> @@ -79,6 +79,34 @@ specific to ARM. >>>>> corresponding interface programming >>>>> registers. >>>>> >>>>> + - CCI PMU node >>>>> + >>>>> + Node name must be "pmu". >>>>> + Parent node must be CCI interconnect node. >>>>> + >>>>> + A CCI pmu node must contain the following properties: >>>>> + >>>>> + - compatible >>>>> + Usage: required >>>>> + Value type: <string> >>>>> + Definition: must be set to one of >>>>> + "arm,cci-400-pmu" >>>>> + "arm,cci-400-pmu,rev0" >>>>> + "arm,cci-400-pmu,rev1" >>>> >>>> Do you really mean only one? Seems like ""arm,cci-400-pmu,rev0", "arm,cci-400-pmu" would be valid. >>>> >>> >>> Hmm... yes both would be valid. But... >>> >>> The event numbering scheme changed between Rev 0 and Rev 1 of the CCI. If the revision is specified then it is used to get the event ranges to validate the events. If not, i.e., "arm,cci-400-pmu" is used, then the driver tries to find the the revision by reading the peripheral id registers. >>> >>> I was trying to make the bindings robust in the face of change in behaviour between different revisons of the IP. >> >> If there is a periph id register why bother with the device tree having different version info in it? >> > > The different version strings are useful when the identification registers are either incorrect or broken. > > But I am not aware of any such platforms currently out there. I can remove the additional compatible strings and rely on the peripheral id register solely. Do you prefer that? Yes please make this change. While I agree the compat field is useful when ID registers are broken, if they are known to be correct I would recommend utilizing them until the situation arises that they arent. -- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
