diff mbox series

[v6,08/11] cpufreq: amd_pstate: add driver working mode status sysfs entry

Message ID 20221202074719.623673-9-perry.yuan@amd.com
State New
Headers
Series Implement AMD Pstate EPP Driver |

Commit Message

Yuan, Perry Dec. 2, 2022, 7:47 a.m. UTC 
  From: Perry Yuan <Perry.Yuan@amd.com>

While amd-pstate driver was loaded with specific driver mode, it will
need to check which mode is enabled for the pstate driver,add this sysfs
entry to show the current status

$ cat /sys/devices/system/cpu/amd-pstate/status
active

Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 44 ++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

Comments

Mario Limonciello Dec. 2, 2022, 3:57 p.m. UTC | #1 
On 12/2/2022 01:47, Perry Yuan wrote:
> From: Perry Yuan <Perry.Yuan@amd.com>
> 
> While amd-pstate driver was loaded with specific driver mode, it will

The *driver* doesn't need to check which mode is enabled from the sysfs 
file, but userspace may want to check this.  I think you should reword 
this accordingly in the commit message.

> need to check which mode is enabled for the pstate driver,add this sysfs
> entry to show the current status
> 
> $ cat /sys/devices/system/cpu/amd-pstate/status
> active
> 
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> ---
>   drivers/cpufreq/amd-pstate.c | 44 ++++++++++++++++++++++++++++++++++++
>   1 file changed, 44 insertions(+)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 6936df6e8642..7f748a579023 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -66,6 +66,8 @@ static bool cppc_active;
>   static int cppc_load __initdata;
>   
>   static struct cpufreq_driver *default_pstate_driver;
> +static struct cpufreq_driver amd_pstate_epp_driver;
> +static struct cpufreq_driver amd_pstate_driver;
>   static struct amd_cpudata **all_cpu_data;
>   static struct amd_pstate_params global_params;
>   
> @@ -807,6 +809,46 @@ static ssize_t store_boost(struct kobject *a,
>   	return count;
>   }
>   
> +static ssize_t amd_pstate_show_status(char *buf)
> +{
> +	if (!default_pstate_driver)
> +		return sysfs_emit(buf, "off\n");
> +
> +	return sysfs_emit(buf, "%s\n", default_pstate_driver == &amd_pstate_epp_driver ?
> +					"active" : "passive");
> +}
> +
> +static int amd_pstate_update_status(const char *buf, size_t size)
> +{
> +	/* FIXME! */
> +	return -EOPNOTSUPP;
> +}

Why not just fix this as part of the series?  It should be no different 
than unloading the driver and reloading it in the appropriate mode, right?

Is this going to be a short term FIXME/TODO or a long term?  If it's 
long term, it might be better to just make the attribute ro and and have 
just the show callback.  Then when you're ready to make it rw you can 
add the store callback, change it from ro to rw and update documentation 
at that time.

> +
> +static ssize_t show_status(struct kobject *kobj,
> +			   struct kobj_attribute *attr, char *buf)
> +{
> +	ssize_t ret;
> +
> +	mutex_lock(&amd_pstate_driver_lock);
> +	ret = amd_pstate_show_status(buf);
> +	mutex_unlock(&amd_pstate_driver_lock);
> +
> +	return ret;
> +}
> +
> +static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
> +			    const char *buf, size_t count)
> +{
> +	char *p = memchr(buf, '\n', count);
> +	int ret;
> +
> +	mutex_lock(&amd_pstate_driver_lock);
> +	ret = amd_pstate_update_status(buf, p ? p - buf : count);
> +	mutex_unlock(&amd_pstate_driver_lock);
> +
> +	return ret < 0 ? ret : count;
> +}
> +
>   cpufreq_freq_attr_ro(amd_pstate_max_freq);
>   cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>   
> @@ -814,6 +856,7 @@ cpufreq_freq_attr_ro(amd_pstate_highest_perf);
>   cpufreq_freq_attr_rw(energy_performance_preference);
>   cpufreq_freq_attr_ro(energy_performance_available_preferences);
>   define_one_global_rw(boost);
> +define_one_global_rw(status);
>   
>   static struct freq_attr *amd_pstate_attr[] = {
>   	&amd_pstate_max_freq,
> @@ -833,6 +876,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
>   
>   static struct attribute *pstate_global_attributes[] = {
>   	&boost.attr,
> +	&status.attr,

In the series I didn't see a matching Documentation update for the new 
sysfs file, can you please add one?

>   	NULL
>   };
>
Yuan, Perry Dec. 8, 2022, 3:55 p.m. UTC | #2 
[AMD Official Use Only - General]

Hi Mario.

> -----Original Message-----
> From: Limonciello, Mario <Mario.Limonciello@amd.com>
> Sent: Friday, December 2, 2022 11:57 PM
> To: Yuan, Perry <Perry.Yuan@amd.com>; rafael.j.wysocki@intel.com; Huang,
> Ray <Ray.Huang@amd.com>; viresh.kumar@linaro.org
> Cc: Sharma, Deepak <Deepak.Sharma@amd.com>; Fontenot, Nathan
> <Nathan.Fontenot@amd.com>; Deucher, Alexander
> <Alexander.Deucher@amd.com>; Huang, Shimmer
> <Shimmer.Huang@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>; Meng,
> Li (Jassmine) <Li.Meng@amd.com>; Karny, Wyes <Wyes.Karny@amd.com>;
> linux-pm@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v6 08/11] cpufreq: amd_pstate: add driver working
> mode status sysfs entry
> 
> On 12/2/2022 01:47, Perry Yuan wrote:
> > From: Perry Yuan <Perry.Yuan@amd.com>
> >
> > While amd-pstate driver was loaded with specific driver mode, it will
> 
> The *driver* doesn't need to check which mode is enabled from the sysfs
> file, but userspace may want to check this.  I think you should reword this
> accordingly in the commit message.
> 
> > need to check which mode is enabled for the pstate driver,add this
> > sysfs entry to show the current status
> >
> > $ cat /sys/devices/system/cpu/amd-pstate/status
> > active
> >
> > Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> > ---
> >   drivers/cpufreq/amd-pstate.c | 44
> ++++++++++++++++++++++++++++++++++++
> >   1 file changed, 44 insertions(+)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 6936df6e8642..7f748a579023 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -66,6 +66,8 @@ static bool cppc_active;
> >   static int cppc_load __initdata;
> >
> >   static struct cpufreq_driver *default_pstate_driver;
> > +static struct cpufreq_driver amd_pstate_epp_driver; static struct
> > +cpufreq_driver amd_pstate_driver;
> >   static struct amd_cpudata **all_cpu_data;
> >   static struct amd_pstate_params global_params;
> >
> > @@ -807,6 +809,46 @@ static ssize_t store_boost(struct kobject *a,
> >   	return count;
> >   }
> >
> > +static ssize_t amd_pstate_show_status(char *buf) {
> > +	if (!default_pstate_driver)
> > +		return sysfs_emit(buf, "off\n");
> > +
> > +	return sysfs_emit(buf, "%s\n", default_pstate_driver ==
> &amd_pstate_epp_driver ?
> > +					"active" : "passive");
> > +}
> > +
> > +static int amd_pstate_update_status(const char *buf, size_t size) {
> > +	/* FIXME! */
> > +	return -EOPNOTSUPP;
> > +}
> 
> Why not just fix this as part of the series?  It should be no different than
> unloading the driver and reloading it in the appropriate mode, right?

There is one kernel hang issue for the amd-pstate driver when unloading it before this. 
I have added one fix patch for this in V7, and added the driver mode switching code as well.
The driver mode can be switched now.

Perry.

> 
> Is this going to be a short term FIXME/TODO or a long term?  If it's long term,
> it might be better to just make the attribute ro and and have just the show
> callback.  Then when you're ready to make it rw you can add the store
> callback, change it from ro to rw and update documentation at that time.
> 

Fixed in V7. It is working well now. 

> > +
> > +static ssize_t show_status(struct kobject *kobj,
> > +			   struct kobj_attribute *attr, char *buf)
> > +{
> > +	ssize_t ret;
> > +
> > +	mutex_lock(&amd_pstate_driver_lock);
> > +	ret = amd_pstate_show_status(buf);
> > +	mutex_unlock(&amd_pstate_driver_lock);
> > +
> > +	return ret;
> > +}
> > +
> > +static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
> > +			    const char *buf, size_t count)
> > +{
> > +	char *p = memchr(buf, '\n', count);
> > +	int ret;
> > +
> > +	mutex_lock(&amd_pstate_driver_lock);
> > +	ret = amd_pstate_update_status(buf, p ? p - buf : count);
> > +	mutex_unlock(&amd_pstate_driver_lock);
> > +
> > +	return ret < 0 ? ret : count;
> > +}
> > +
> >   cpufreq_freq_attr_ro(amd_pstate_max_freq);
> >   cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
> >
> > @@ -814,6 +856,7 @@ cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> >   cpufreq_freq_attr_rw(energy_performance_preference);
> >   cpufreq_freq_attr_ro(energy_performance_available_preferences);
> >   define_one_global_rw(boost);
> > +define_one_global_rw(status);
> >
> >   static struct freq_attr *amd_pstate_attr[] = {
> >   	&amd_pstate_max_freq,
> > @@ -833,6 +876,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
> >
> >   static struct attribute *pstate_global_attributes[] = {
> >   	&boost.attr,
> > +	&status.attr,
> 
> In the series I didn't see a matching Documentation update for the new
> sysfs file, can you please add one?

Added in V7.
Please help to take a look

> 
> >   	NULL
> >   };
> >
diff mbox series

Patch

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 6936df6e8642..7f748a579023 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -66,6 +66,8 @@  static bool cppc_active;
 static int cppc_load __initdata;
 
 static struct cpufreq_driver *default_pstate_driver;
+static struct cpufreq_driver amd_pstate_epp_driver;
+static struct cpufreq_driver amd_pstate_driver;
 static struct amd_cpudata **all_cpu_data;
 static struct amd_pstate_params global_params;
 
@@ -807,6 +809,46 @@  static ssize_t store_boost(struct kobject *a,
 	return count;
 }
 
+static ssize_t amd_pstate_show_status(char *buf)
+{
+	if (!default_pstate_driver)
+		return sysfs_emit(buf, "off\n");
+
+	return sysfs_emit(buf, "%s\n", default_pstate_driver == &amd_pstate_epp_driver ?
+					"active" : "passive");
+}
+
+static int amd_pstate_update_status(const char *buf, size_t size)
+{
+	/* FIXME! */
+	return -EOPNOTSUPP;
+}
+
+static ssize_t show_status(struct kobject *kobj,
+			   struct kobj_attribute *attr, char *buf)
+{
+	ssize_t ret;
+
+	mutex_lock(&amd_pstate_driver_lock);
+	ret = amd_pstate_show_status(buf);
+	mutex_unlock(&amd_pstate_driver_lock);
+
+	return ret;
+}
+
+static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
+			    const char *buf, size_t count)
+{
+	char *p = memchr(buf, '\n', count);
+	int ret;
+
+	mutex_lock(&amd_pstate_driver_lock);
+	ret = amd_pstate_update_status(buf, p ? p - buf : count);
+	mutex_unlock(&amd_pstate_driver_lock);
+
+	return ret < 0 ? ret : count;
+}
+
 cpufreq_freq_attr_ro(amd_pstate_max_freq);
 cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
 
@@ -814,6 +856,7 @@  cpufreq_freq_attr_ro(amd_pstate_highest_perf);
 cpufreq_freq_attr_rw(energy_performance_preference);
 cpufreq_freq_attr_ro(energy_performance_available_preferences);
 define_one_global_rw(boost);
+define_one_global_rw(status);
 
 static struct freq_attr *amd_pstate_attr[] = {
 	&amd_pstate_max_freq,
@@ -833,6 +876,7 @@  static struct freq_attr *amd_pstate_epp_attr[] = {
 
 static struct attribute *pstate_global_attributes[] = {
 	&boost.attr,
+	&status.attr,
 	NULL
 };