From: punit.agrawal@arm•com (Punit Agrawal)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] drivers: CCI: add ARM CCI PMU support
Date: Fri, 16 Aug 2013 11:31:08 +0100 [thread overview]
Message-ID: <520DFF6C.1040500@arm.com> (raw)
In-Reply-To: <ADB3A138-838D-4437-853A-ABFCB0B32FAB@codeaurora.org>
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@arm•com>
>>>> Cc: Nicolas Pitre <nico@linaro•org>
>>>> Cc: Dave Martin <dave.martin@linaro•org>
>>>> Cc: Rob Herring <rob.herring@calxeda•com>
>>>> Cc: Will Deacon <will.deacon@arm•com>
>>>> Signed-off-by: Punit Agrawal <punit.agrawal@arm•com>
>>>> Reviewed-by: Will Deacon <will.deacon@arm•com>
>>>> ---
>>>> 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?
Cheers,
Punit
> - k
>
next prev parent reply other threads:[~2013-08-16 10:31 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-11 3:00 [PATCH] drivers: CCI: add ARM CCI PMU support Punit Agrawal
2013-08-05 11:37 ` Punit Agrawal
2013-08-07 1:45 ` Will Deacon
2013-08-12 13:59 ` Will Deacon
2013-08-12 16:08 ` Will Deacon
2013-08-12 16:58 ` Punit Agrawal
2013-08-14 21:03 ` Kumar Gala
2013-08-14 22:38 ` Rob Herring
2013-08-15 10:01 ` Punit Agrawal
2013-08-15 9:10 ` Punit Agrawal
2013-08-15 16:25 ` Kumar Gala
2013-08-16 10:31 ` Punit Agrawal [this message]
2013-08-16 10:53 ` Kumar Gala
2013-08-15 19:00 ` Kumar Gala
2013-08-16 10:56 ` Punit Agrawal
2013-08-16 11:31 ` Kumar Gala
2013-08-16 12:41 ` Punit Agrawal
2013-08-14 21:06 ` Stephen Warren
2013-08-14 21:09 ` Kumar Gala
2013-08-14 21:13 ` Stephen Warren
2013-08-14 21:16 ` Kumar Gala
2013-08-15 10:09 ` Punit Agrawal
2013-08-16 17:19 ` [PATCH v2] " Punit Agrawal
2013-08-16 18:31 ` Stephen Warren
2013-08-19 11:14 ` Punit Agrawal
2013-08-19 16:15 ` Stephen Warren
2013-08-16 18:47 ` Kumar Gala
2013-08-19 11:21 ` Punit Agrawal
2013-08-20 15:07 ` Will Deacon
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