Re: [PATCH] coresight: add PM runtime calls to coresight_simple_func()

From	Mathieu Poirier <mathieu.poirier@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] coresight: add PM runtime calls to coresight_simple_func()
Date	2016-06-23 19:20 +0200
Message-ID	<rNgsh-4IF-5@gated-at.bofh.it> (permalink)
References	<rL642-15V-33@gated-at.bofh.it> <rNfPz-4cB-19@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 23 June 2016 at 10:37, Sudeep Holla <sudeep.holla@arm.com> wrote:
>
>
> On 17/06/16 18:41, Mathieu Poirier wrote:
>>
>> It is mandatory to enable a coresight block's power domain before
>> trying to access management registers.  Otherwise the transaction
>> simply stalls, leading to a system hang.
>>
>> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
>> ---
>>   drivers/hwtracing/coresight/coresight-priv.h | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-priv.h
>> b/drivers/hwtracing/coresight/coresight-priv.h
>> index ad975c58080d..b047241e7496 100644
>> --- a/drivers/hwtracing/coresight/coresight-priv.h
>> +++ b/drivers/hwtracing/coresight/coresight-priv.h
>> @@ -16,6 +16,7 @@
>>   #include <linux/bitops.h>
>>   #include <linux/io.h>
>>   #include <linux/coresight.h>
>> +#include <linux/pm_runtime.h>
>>
>>   /*
>>    * Coresight management registers (0xf00-0xfcc)
>> @@ -42,8 +43,10 @@ static ssize_t name##_show(struct device *_dev,
>> \
>>                            struct device_attribute *attr, char *buf)    \
>>   {                                                                     \
>>         type *drvdata = dev_get_drvdata(_dev->parent);                  \
>> +       pm_runtime_get_sync(_dev->parent);                              \
>>         return scnprintf(buf, PAGE_SIZE, "0x%x\n",                      \
>>                          readl_relaxed(drvdata->base + offset));        \
>> +       pm_runtime_put_sync(_dev->parent);                              \
>
>
> This is wrong, I just noticed when I was playing around this.
> Perhaps you meant to do this before returning ? I wonder why compiler
> doesn't throw any error.

Yes of course - I'll respin.

>
> --
> Regards,
> Sudeep

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[PATCH] coresight: add PM runtime calls to coresight_simple_func() Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-06-17 19:50 +0200
  Re: [PATCH] coresight: add PM runtime calls to  coresight_simple_func() Sudeep Holla <sudeep.holla@arm.com> - 2016-06-23 18:40 +0200
    Re: [PATCH] coresight: add PM runtime calls to coresight_simple_func() Mathieu Poirier <mathieu.poirier@linaro.org> - 2016-06-23 19:20 +0200

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