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Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon SoC event counters

From Anurup M <anurupvasu@gmail.com>
Newsgroups linux.kernel
Subject Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon SoC event counters
Date 2017-03-27 08:40 +0200
Message-ID <tpwtP-3Lz-9@gated-at.bofh.it> (permalink)
References <tjmdQ-87B-9@gated-at.bofh.it> <tnviy-5Yp-25@gated-at.bofh.it> <touu5-8u8-13@gated-at.bofh.it> <tow2S-10z-21@gated-at.bofh.it>
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On Friday 24 March 2017 05:27 PM, Mark Rutland wrote:
>> +/* hip05/06 chips L3C bank identifier */
>> >+static u32 l3c_bankid_map_v1[MAX_BANKS] = {
>> >+    0x02, 0x04, 0x01, 0x08,
>> >+};
>> >+
>> >+/* hip07 chip L3C bank identifier */
>> >+static u32 l3c_bankid_map_v2[MAX_BANKS] = {
>> >+    0x01, 0x02, 0x03, 0x04,
>> >+};
>> >
>> >Is my approach OK? or can be improved?
> I think it would make more sense for this to be described in the DT.

Ok. Shall describe it in DT.

> [...]
>
>> I shall handle the error internally and propagate it until a void
>> >function (pmu->start, pmu->stop, pmu->del etc. are void).
>> >e.g. in the scenario pmu->add ---> pmu->start. If start fail,
>> >pmu->add cannot catch it and continues.
>> >the counter index could be cleared when pmu->del is called later.
>> >
>> >Is this fine? Any suggestion to handle it?
> Propagating it up to a void function, only to silently fail is not good.
>
> Given it seems this should only happen if there is a major HW problem,
> I'd be happier with a BUG_ON() in the djtag accessors.

Yes, it occur only when major HQ problem. I would add BUG_ON in djtag 
and simplify callers.

> [...]
>
>>> > >In the absence of pmu::{enable,disable}, you must disallow groups, since
>>> > >their events will be enabled for different periods of time.
>> >
>> >For L3 cache and MN PMU, pmu::{enable,disable}is present. But in
>> >case of Hisilicon DDRC PMU,
>> >it is not available. It only support continuous counting. I shall
>> >disallow groups when adding support
>> >for DDRC PMU.
> Given this code does not currently support the DDRC, please simplify
> the coder to assume these callbacks always exist. We can alter it when
> DDRC support arrives.

Ok. Sure. Shall remove all similar checks added for DDRC in this file to 
simplify.

Thanks,
Anurup

> Thanks,
> Mark.

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Thread

Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon  SoC event counters Mark Rutland <mark.rutland@arm.com> - 2017-03-21 18:00 +0100
  Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon  SoC event counters Anurup M <anurupvasu@gmail.com> - 2017-03-24 11:20 +0100
    Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon  SoC event counters Mark Rutland <mark.rutland@arm.com> - 2017-03-24 13:00 +0100
      Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon  SoC event counters Anurup M <anurupvasu@gmail.com> - 2017-03-27 08:40 +0200
  Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon  SoC event counters Anurup M <anurupvasu@gmail.com> - 2017-03-30 11:50 +0200
    Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon  SoC event counters Mark Rutland <mark.rutland@arm.com> - 2017-03-30 12:50 +0200
      Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon  SoC event counters Anurup M <anurupvasu@gmail.com> - 2017-03-31 16:20 +0200
        Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon  SoC event counters Mark Rutland <mark.rutland@arm.com> - 2017-03-31 16:30 +0200
          Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon  SoC event counters Anurup M <anurupvasu@gmail.com> - 2017-03-31 17:10 +0200

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