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SubjectRe: [PATCH] coresight: replicator: Reset replicator if context is lost
Hi Mathieu,

On 2020-05-11 21:49, Mathieu Poirier wrote:
> Hi Sai,
>
> On Mon, 11 May 2020 at 02:34, Sai Prakash Ranjan
> <saiprakash.ranjan@codeaurora.org> wrote:
>>
>> On some QCOM SoCs, replicators in Always-On domain loses its
>> context as soon as the clock is disabled. Currently as a part
>> of pm_runtime workqueue, clock is disabled after the replicator
>> is initialized by amba_pm_runtime_suspend assuming that context
>> is not lost which is not true for replicators with such
>> limitations. Hence check the replicator idfilter registers
>> in dynamic_replicator_enable() and reset again.
>>
>> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
>> ---
>>
>> More info here - https://lore.kernel.org/patchwork/patch/1231182/
>>
>> ---
>> drivers/hwtracing/coresight/coresight-replicator.c | 11 +++++++++++
>> 1 file changed, 11 insertions(+)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-replicator.c
>> b/drivers/hwtracing/coresight/coresight-replicator.c
>> index e7dc1c31d20d..11df63f51071 100644
>> --- a/drivers/hwtracing/coresight/coresight-replicator.c
>> +++ b/drivers/hwtracing/coresight/coresight-replicator.c
>> @@ -68,6 +68,17 @@ static int dynamic_replicator_enable(struct
>> replicator_drvdata *drvdata,
>> int rc = 0;
>> u32 reg;
>>
>> + /*
>> + * On some QCOM SoCs with replicators in Always-On domain,
>> disabling
>> + * clock will result in replicator losing its context.
>> Currently
>> + * as a part of pm_runtime workqueue, amba_pm_runtime_suspend
>> disables
>> + * clock assuming the context is not lost which is not true
>> for cases
>> + * with hardware limitations as the above.
>> + */
>> + if ((readl_relaxed(drvdata->base + REPLICATOR_IDFILTER0) == 0)
>> &&
>> + (readl_relaxed(drvdata->base + REPLICATOR_IDFILTER1) ==
>> 0))
>> + dynamic_replicator_reset(drvdata);
>> +
>
> Based on your comment here[1] and the ongoing conversation, I will
> wait for a V2.
>
> Thanks,
> Mathieu
>
> [1]. https://lkml.org/lkml/2020/5/11/650
>

Yes, I will post a v2 once we have consensus regarding which way we need
to
add a workaround for such QCOM SoCs.

Thanks,
Sai

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