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SubjectRe: [PATCH] coresight: etm4x: Modify core-commit of cpu to avoid the overflow of HiSilicon ETM
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On 2020/11/23 22:12, Suzuki K Poulose wrote:
> Hi Qi
>
> Thanks for the changes. Mostly looks good to me, except for the
> name of the call back.
>
>
Hi Suzuki,
ok, I'll send a new patch to change the name of call back.

Thanks
Qi
> On 11/23/20 1:29 PM, Qi Liu wrote:
>> The ETM device can't keep up with the core pipeline when cpu core
>> is at full speed. This may cause overflow within core and its ETM.
>> This is a common phenomenon on ETM devices.
>>
>> On HiSilicon Hip08 platform, a specific feature is added to set
>> core pipeline. So commit rate can be reduced manually to avoid ETM
>> overflow.
>>
>> Signed-off-by: Qi Liu <liuqi115@huawei.com>
>
>
>> ---
>> Change since v1:
>> - add CONFIG_ETM4X_IMPDEF_FEATURE and CONFIG_ETM4X_IMPDEF_HISILICON
>> to keep specific feature off platforms which don't use it.
>> Change since v2:
>> - remove some unused variable.
>> Change since v3:
>> - use read/write_sysreg_s() to access register.
>>
>> drivers/hwtracing/coresight/Kconfig | 9 +++
>> drivers/hwtracing/coresight/coresight-etm4x-core.c | 84 ++++++++++++++++++++++
>> drivers/hwtracing/coresight/coresight-etm4x.h | 12 ++++
>> 3 files changed, 105 insertions(+)
>>
>
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
>> index eefc737..1784975 100644
>> --- a/drivers/hwtracing/coresight/coresight-etm4x.h
>> +++ b/drivers/hwtracing/coresight/coresight-etm4x.h
>> @@ -8,6 +8,7 @@
>>
>> #include <asm/local.h>
>> #include <linux/spinlock.h>
>> +#include <linux/types.h>
>> #include "coresight-priv.h"
>>
>> /*
>> @@ -203,6 +204,11 @@
>> /* Interpretation of resource numbers change at ETM v4.3 architecture */
>> #define ETM4X_ARCH_4V3 0x43
>>
>> +enum etm_impdef_type {
>> + ETM4_IMPDEF_HISI_CORE_COMMIT,
>> + ETM4_IMPDEF_FEATURE_MAX,
>> +};
>> +
>> /**
>> * struct etmv4_config - configuration information related to an ETMv4
>> * @mode: Controls various modes supported by this ETM.
>> @@ -415,6 +421,7 @@ struct etmv4_save_state {
>> * @state_needs_restore: True when there is context to restore after PM exit
>> * @skip_power_up: Indicates if an implementation can skip powering up
>> * the trace unit.
>> + * @arch_features: Bitmap of arch features of etmv4 devices.
>> */
>> struct etmv4_drvdata {
>> void __iomem *base;
>> @@ -463,6 +470,11 @@ struct etmv4_drvdata {
>> struct etmv4_save_state *save_state;
>> bool state_needs_restore;
>> bool skip_power_up;
>> + DECLARE_BITMAP(arch_features, ETM4_IMPDEF_FEATURE_MAX);
>> +};
>> +
>> +struct etm4_arch_features {
>> + void (*set_commit)(bool enable);
>
> The set_commit is too hisilicon specific :-). Could we please rename
> this to soemthing more generic. The callback for hisilicon etms, could still
> be xx_commit". May be simply call it
>
> callback() ?
>
> or may be even
> arch_callback() ?
>
>
>> };
>
> nit: This need not be part of the header file, as it is not used
> outside the etm4x-core.c
>
> Suzuki
>
> .
>

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