* [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up
@ 2020-10-16 10:10 Sai Prakash Ranjan
2020-10-16 11:21 ` Suzuki Poulose
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Sai Prakash Ranjan @ 2020-10-16 10:10 UTC (permalink / raw)
To: Mathieu Poirier, Suzuki K Poulose, Mike Leach
Cc: coresight, Stephen Boyd, denik, linux-arm-msm, linux-kernel,
linux-arm-kernel, Sai Prakash Ranjan
There is a bug on the systems supporting to skip power up
(qcom,skip-power-up) where setting LPOVERRIDE bit(low-power
state override behaviour) will result in CPU hangs/lockups
even on the implementations which supports it. So skip
setting the LPOVERRIDE bit for such platforms.
Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace unit power up")
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
---
drivers/hwtracing/coresight/coresight-etm4x-core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index abd706b216ac..6096d7abf80d 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -779,7 +779,7 @@ static void etm4_init_arch_data(void *info)
* LPOVERRIDE, bit[23] implementation supports
* low-power state override
*/
- if (BMVAL(etmidr5, 23, 23))
+ if (BMVAL(etmidr5, 23, 23) && (!drvdata->skip_power_up))
drvdata->lpoverride = true;
else
drvdata->lpoverride = false;
base-commit: 3477326277451000bc667dfcc4fd0774c039184c
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up
2020-10-16 10:10 [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up Sai Prakash Ranjan
@ 2020-10-16 11:21 ` Suzuki Poulose
2020-10-16 11:47 ` Sai Prakash Ranjan
2020-10-16 16:31 ` Mathieu Poirier
2020-12-29 20:15 ` patchwork-bot+linux-arm-msm
2 siblings, 1 reply; 7+ messages in thread
From: Suzuki Poulose @ 2020-10-16 11:21 UTC (permalink / raw)
To: Sai Prakash Ranjan, Mathieu Poirier, Mike Leach
Cc: coresight, Stephen Boyd, denik, linux-arm-msm, linux-kernel,
linux-arm-kernel
Hi Sai,
On 10/16/20 11:10 AM, Sai Prakash Ranjan wrote:
> There is a bug on the systems supporting to skip power up
> (qcom,skip-power-up) where setting LPOVERRIDE bit(low-power
> state override behaviour) will result in CPU hangs/lockups
> even on the implementations which supports it. So skip
> setting the LPOVERRIDE bit for such platforms.
>
> Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace unit power up")
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
The fix is fine by me. Btw, is there a hardware Erratum assigned for
this ? It would be good to have the Erratum documented somewhere,
preferrably ( Documentation/arm64/silicon-errata.rst )
> ---
> drivers/hwtracing/coresight/coresight-etm4x-core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index abd706b216ac..6096d7abf80d 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -779,7 +779,7 @@ static void etm4_init_arch_data(void *info)
> * LPOVERRIDE, bit[23] implementation supports
> * low-power state override
> */
> - if (BMVAL(etmidr5, 23, 23))
> + if (BMVAL(etmidr5, 23, 23) && (!drvdata->skip_power_up))
> drvdata->lpoverride = true;
> else
> drvdata->lpoverride = false;
>
> base-commit: 3477326277451000bc667dfcc4fd0774c039184c
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up
2020-10-16 11:21 ` Suzuki Poulose
@ 2020-10-16 11:47 ` Sai Prakash Ranjan
2020-10-16 13:15 ` Suzuki Poulose
0 siblings, 1 reply; 7+ messages in thread
From: Sai Prakash Ranjan @ 2020-10-16 11:47 UTC (permalink / raw)
To: Suzuki Poulose
Cc: Mathieu Poirier, Mike Leach, coresight, Stephen Boyd, denik,
linux-arm-msm, linux-kernel, linux-arm-kernel
Hi Suzuki,
On 2020-10-16 16:51, Suzuki Poulose wrote:
> Hi Sai,
>
> On 10/16/20 11:10 AM, Sai Prakash Ranjan wrote:
>> There is a bug on the systems supporting to skip power up
>> (qcom,skip-power-up) where setting LPOVERRIDE bit(low-power
>> state override behaviour) will result in CPU hangs/lockups
>> even on the implementations which supports it. So skip
>> setting the LPOVERRIDE bit for such platforms.
>>
>> Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace unit
>> power up")
>> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
>
> The fix is fine by me. Btw, is there a hardware Erratum assigned for
> this ? It would be good to have the Erratum documented somewhere,
> preferrably ( Documentation/arm64/silicon-errata.rst )
>
No, afaik we don't have any erratum assigned to this bug.
It was already present in downstream kernel and since we
support these targets with the previous HW bug
(qcom,skip-power-up) now in upstream, we would need this
fix in upstream kernel as well.
Thanks,
Sai
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up
2020-10-16 11:47 ` Sai Prakash Ranjan
@ 2020-10-16 13:15 ` Suzuki Poulose
2020-10-16 13:40 ` Sai Prakash Ranjan
0 siblings, 1 reply; 7+ messages in thread
From: Suzuki Poulose @ 2020-10-16 13:15 UTC (permalink / raw)
To: Sai Prakash Ranjan
Cc: Mathieu Poirier, Mike Leach, coresight, Stephen Boyd, denik,
linux-arm-msm, linux-kernel, linux-arm-kernel
On 10/16/20 12:47 PM, Sai Prakash Ranjan wrote:
> Hi Suzuki,
>
> On 2020-10-16 16:51, Suzuki Poulose wrote:
>> Hi Sai,
>>
>> On 10/16/20 11:10 AM, Sai Prakash Ranjan wrote:
>>> There is a bug on the systems supporting to skip power up
>>> (qcom,skip-power-up) where setting LPOVERRIDE bit(low-power
>>> state override behaviour) will result in CPU hangs/lockups
>>> even on the implementations which supports it. So skip
>>> setting the LPOVERRIDE bit for such platforms.
>>>
>>> Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace
>>> unit power up")
>>> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
>>
>> The fix is fine by me. Btw, is there a hardware Erratum assigned for
>> this ? It would be good to have the Erratum documented somewhere,
>> preferrably ( Documentation/arm64/silicon-errata.rst )
>>
>
> No, afaik we don't have any erratum assigned to this bug.
Ok. Please double check, if there are any.
> It was already present in downstream kernel and since we
> support these targets with the previous HW bug
> (qcom,skip-power-up) now in upstream, we would need this
> fix in upstream kernel as well.
I understand the need for the fix and we must fix it. I was
looking to document this in the central place for errata's
handled in the kernel. And I missed asking this question
when the original patch was posted. So, thought of asking
the question now anyways. Better late than never ;-)
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up
2020-10-16 13:15 ` Suzuki Poulose
@ 2020-10-16 13:40 ` Sai Prakash Ranjan
0 siblings, 0 replies; 7+ messages in thread
From: Sai Prakash Ranjan @ 2020-10-16 13:40 UTC (permalink / raw)
To: Suzuki Poulose
Cc: Mathieu Poirier, Mike Leach, coresight, Stephen Boyd, denik,
linux-arm-msm, linux-kernel, linux-arm-kernel
Hi Suzuki,
On 2020-10-16 18:45, Suzuki Poulose wrote:
> On 10/16/20 12:47 PM, Sai Prakash Ranjan wrote:
>> Hi Suzuki,
>>
>> On 2020-10-16 16:51, Suzuki Poulose wrote:
>>> Hi Sai,
>>>
>>> On 10/16/20 11:10 AM, Sai Prakash Ranjan wrote:
>>>> There is a bug on the systems supporting to skip power up
>>>> (qcom,skip-power-up) where setting LPOVERRIDE bit(low-power
>>>> state override behaviour) will result in CPU hangs/lockups
>>>> even on the implementations which supports it. So skip
>>>> setting the LPOVERRIDE bit for such platforms.
>>>>
>>>> Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace
>>>> unit power up")
>>>> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
>>>
>>> The fix is fine by me. Btw, is there a hardware Erratum assigned for
>>> this ? It would be good to have the Erratum documented somewhere,
>>> preferrably ( Documentation/arm64/silicon-errata.rst )
>>>
>>
>> No, afaik we don't have any erratum assigned to this bug.
>
> Ok. Please double check, if there are any.
>
Sure I will check again.
>> It was already present in downstream kernel and since we
>> support these targets with the previous HW bug
>> (qcom,skip-power-up) now in upstream, we would need this
>> fix in upstream kernel as well.
>
> I understand the need for the fix and we must fix it. I was
> looking to document this in the central place for errata's
> handled in the kernel. And I missed asking this question
> when the original patch was posted. So, thought of asking
> the question now anyways. Better late than never ;-)
>
> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Thanks. One more thing, does the internal erratum
number (if it exists) is good enough to be documented in
the Documentation/arm64/silicon-errata.rst ? I ask this
because outside qualcomm, it won't mean much right.
Thanks,
Sai
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up
2020-10-16 10:10 [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up Sai Prakash Ranjan
2020-10-16 11:21 ` Suzuki Poulose
@ 2020-10-16 16:31 ` Mathieu Poirier
2020-12-29 20:15 ` patchwork-bot+linux-arm-msm
2 siblings, 0 replies; 7+ messages in thread
From: Mathieu Poirier @ 2020-10-16 16:31 UTC (permalink / raw)
To: Sai Prakash Ranjan
Cc: Suzuki K Poulose, Mike Leach, coresight, Stephen Boyd, denik,
linux-arm-msm, linux-kernel, linux-arm-kernel
On Fri, Oct 16, 2020 at 03:40:25PM +0530, Sai Prakash Ranjan wrote:
> There is a bug on the systems supporting to skip power up
> (qcom,skip-power-up) where setting LPOVERRIDE bit(low-power
> state override behaviour) will result in CPU hangs/lockups
> even on the implementations which supports it. So skip
> setting the LPOVERRIDE bit for such platforms.
>
> Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace unit power up")
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> ---
> drivers/hwtracing/coresight/coresight-etm4x-core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index abd706b216ac..6096d7abf80d 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -779,7 +779,7 @@ static void etm4_init_arch_data(void *info)
> * LPOVERRIDE, bit[23] implementation supports
> * low-power state override
> */
> - if (BMVAL(etmidr5, 23, 23))
> + if (BMVAL(etmidr5, 23, 23) && (!drvdata->skip_power_up))
> drvdata->lpoverride = true;
> else
> drvdata->lpoverride = false;
>
I have applied your patch.
Thanks,
Mathieu
> base-commit: 3477326277451000bc667dfcc4fd0774c039184c
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up
2020-10-16 10:10 [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up Sai Prakash Ranjan
2020-10-16 11:21 ` Suzuki Poulose
2020-10-16 16:31 ` Mathieu Poirier
@ 2020-12-29 20:15 ` patchwork-bot+linux-arm-msm
2 siblings, 0 replies; 7+ messages in thread
From: patchwork-bot+linux-arm-msm @ 2020-12-29 20:15 UTC (permalink / raw)
To: Sai Prakash Ranjan; +Cc: linux-arm-msm
Hello:
This patch was applied to qcom/linux.git (refs/heads/for-next):
On Fri, 16 Oct 2020 15:40:25 +0530 you wrote:
> There is a bug on the systems supporting to skip power up
> (qcom,skip-power-up) where setting LPOVERRIDE bit(low-power
> state override behaviour) will result in CPU hangs/lockups
> even on the implementations which supports it. So skip
> setting the LPOVERRIDE bit for such platforms.
>
> Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace unit power up")
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
>
> [...]
Here is the summary with links:
- coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up
https://git.kernel.org/qcom/c/ac0f82b1b495
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-12-29 20:18 UTC | newest]
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2020-10-16 10:10 [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up Sai Prakash Ranjan
2020-10-16 11:21 ` Suzuki Poulose
2020-10-16 11:47 ` Sai Prakash Ranjan
2020-10-16 13:15 ` Suzuki Poulose
2020-10-16 13:40 ` Sai Prakash Ranjan
2020-10-16 16:31 ` Mathieu Poirier
2020-12-29 20:15 ` patchwork-bot+linux-arm-msm
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