Re: [PATCH 3/7] ARM: perf_event: Add basic support for Krait CPU PMUs

[Stephen Boyd <sboyd@codeaurora.org>]

(Adding DT reviewers)

On 01/09/14 03:04, Will Deacon wrote:
> On Wed, Jan 08, 2014 at 10:59:40PM +0000, Stephen Boyd wrote:
>
>> +static int krait_pmu_init(struct arm_pmu *cpu_pmu)
>> +{
>> +	u32 id = read_cpuid_id() & 0xffffff00;
>> +
>> +	armv7pmu_init(cpu_pmu);
>> +	cpu_pmu->name		= "ARMv7 Krait";
>> +	/* Some early versions of Krait don't support PC write events */
>> +	if (id == 0x511f0400 || id == 0x510f0600)
>> +		cpu_pmu->map_event	= krait_map_event_no_branch;
> Hmm, I'd really rather this information came via the DT. In fact, you could
> just drop the branch event from your main map_event_function and keep things
> simple. It depends how badly you want to advertise it in perf list :)
>

Not every version of Krait is missing support for this event, so I'd
like to keep it so things like perf stat show branch counts. How about I
add a bool property to the pmu node indicating that this PMU is missing
support for the PC write events? Something like "no-pc-write"?

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