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[RFC,06/27] PM / Domains: add debugfs 'states' and 'timings' seq files

Message ID 1447799871-56374-7-git-send-email-lina.iyer@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Lina Iyer Nov. 17, 2015, 10:37 p.m. UTC
From: Marc Titinger <mtitinger@baylibre.com>

This purpose of these debug seq-files is to help investigate
generic power domain state transitions, based on device constraints.
requires the "multiple states" patches from Axel Haslam.

also rename 'summary' from 'pm_genpd_summary'

sample output for 'states'

Comments

Ulf Hansson Dec. 11, 2015, 11:46 a.m. UTC | #1
On 17 November 2015 at 23:37, Lina Iyer <lina.iyer@linaro.org> wrote:
> From: Marc Titinger <mtitinger@baylibre.com>
>
> This purpose of these debug seq-files is to help investigate
> generic power domain state transitions, based on device constraints.
> requires the "multiple states" patches from Axel Haslam.

This last sentence doesn't belong in the change-log, please remove it.

>
> also rename 'summary' from 'pm_genpd_summary'
>
> sample output for 'states'
> ==========================
>
>   Domain             State name        Eval = 2200nter + Exit = Min_off_on (ns)
> -----------------------------------------------------------------------
> a53_pd               cluster-sleep-0      1500000+800000=2300000
> a57_pd               d1-retention         1000000+800000=1800000
> a57_pd               cluster-sleep-0      1500000+800000=2300000
>
> sample output for 'timings'
> ===========================
>
>     Domain Devices, Timings in ns
>                        Stop/Start Save/Restore, Effective
> ----------------------------------------------------  ---
> a53_pd
>     /cpus/cpu@100        1060  /660    1580  /1940  ,0 (cached stop)
>     /cpus/cpu@101        1060  /740    1520  /1600  ,0 (cached stop)
>     /cpus/cpu@102        880   /620    1380  /1780  ,0 (cached stop)
>     /cpus/cpu@103        1080  /640    1340  /1600  ,0 (cached stop)
> a57_pd
>     /cpus/cpu@0          1160  /740    3280  /1800  ,0 (cached stop)
>     /cpus/cpu@1          780   /1400   1440  /2080  ,0 (cached stop)
>     /D1                  600   /540    7140  /6420  ,2199460 (cached stop)
>
> Signed-off-by: Marc Titinger <mtitinger@baylibre.com>

A general comment. Static functions in genpd shall start with one of
the following prefix.

genpd_*
_genpd_*
__genpd_*

Please change accordingly.

> ---
>  drivers/base/power/domain.c | 115 +++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 107 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index c300293..9a0df09 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -2169,21 +2169,120 @@ static const struct file_operations pm_genpd_summary_fops = {
>         .release = single_release,
>  };
>
> +static int pm_genpd_states_show(struct seq_file *s, void *data)
> +{
> +       struct generic_pm_domain *genpd;
> +
> +       seq_puts(s,
> +                "\n  Domain             State name        Enter + Exit = Min_off_on (ns)\n");
> +       seq_puts(s,
> +                "-----------------------------------------------------------------------\n");
> +

You must hold the gpd_list_lock while traversing the gpd list.

> +       list_for_each_entry(genpd, &gpd_list, gpd_list_node) {
> +
> +               int i;
> +
> +               for (i = 0; i < genpd->state_count; i++) {

To be sure you have valid data, you should hold the genpd lock here.

> +                       seq_printf(s, "%-20s %-20s %lld+%lld=%lld\n",
> +                                  genpd->name,
> +                                  genpd->states[i].name,
> +                                  genpd->states[i].power_on_latency_ns,
> +                                  genpd->states[i].power_off_latency_ns,
> +                                  genpd->states[i].power_off_latency_ns
> +                                  + genpd->states[i].power_on_latency_ns);
> +               }
> +
> +       }
> +
> +       seq_puts(s, "\n");
> +
> +       return 0;
> +}
> +
> +static int pm_genpd_states_open(struct inode *inode, struct file *file)
> +{
> +       return single_open(file, pm_genpd_states_show, NULL);
> +}
> +
> +static const struct file_operations pm_genpd_states_fops = {
> +       .open = pm_genpd_states_open,
> +       .read = seq_read,
> +       .llseek = seq_lseek,
> +       .release = single_release,
> +};
> +
> +static int pm_genpd_timing_show(struct seq_file *s, void *data)
> +{
> +       struct generic_pm_domain *genpd;
> +
> +       seq_puts(s, "\n    Domain Devices, Timings in ns\n");
> +       seq_puts(s,
> +                "                       Stop/Start Save/Restore, Effective\n");
> +       seq_puts(s,
> +                "----------------------------------------------------  ---\n");
> +

You must hold the gpd_list_lock while traversing the gpd list.


> +       list_for_each_entry(genpd, &gpd_list, gpd_list_node) {
> +               struct pm_domain_data *pm_data;
> +
> +               seq_printf(s, "%-30s", genpd->name);
> +

You must hold the genpd lock while traversing the device list.

> +               list_for_each_entry(pm_data, &genpd->dev_list, list_node) {
> +                       struct gpd_timing_data *td = &to_gpd_data(pm_data)->td;
> +
> +                       if (!pm_data->dev->of_node)
> +                               continue;
> +
> +                       seq_printf(s,
> +                                  "\n    %-20s %-6lld/%-6lld %-6lld/%-6lld,%lld %s%s",
> +                                  pm_data->dev->of_node->full_name,
> +                                  td->stop_latency_ns, td->start_latency_ns,
> +                                  td->save_state_latency_ns,
> +                                  td->restore_state_latency_ns,

This needs a re-base as these values have been merged.

> +                                  td->effective_constraint_ns,
> +                                  td->cached_stop_ok ? "(cached stop) " : "",
> +                                  td->constraint_changed ? "(changed)" : "");
> +               }
> +               seq_puts(s, "\n");
> +       }
> +       return 0;
> +}
> +
> +static int pm_genpd_timing_open(struct inode *inode, struct file *file)
> +{
> +       return single_open(file, pm_genpd_timing_show, NULL);
> +}
> +
> +static const struct file_operations pm_genpd_timing_fops = {
> +       .open = pm_genpd_timing_open,
> +       .read = seq_read,
> +       .llseek = seq_lseek,
> +       .release = single_release,
> +};
> +
>  static int __init pm_genpd_debug_init(void)
>  {
> -       struct dentry *d;
> +       struct dentry *d = NULL;
>
>         pm_genpd_debugfs_dir = debugfs_create_dir("pm_genpd", NULL);
>
> -       if (!pm_genpd_debugfs_dir)
> -               return -ENOMEM;
> +       if (pm_genpd_debugfs_dir)

In case when CONFIG_DEBUG_FS is unset, this doesn't work very well, as
pm_genpd_debugfs_dir will contain an error code.

Since you are anyway make quite big change to the debugfs support for
genpd, perhaps you can try to fix that up as well!?

> +               d = debugfs_create_file("summary", S_IRUGO,
> +                               pm_genpd_debugfs_dir, NULL,
> +                               &pm_genpd_summary_fops);
> +       if (d)
> +               d = debugfs_create_file("states", S_IRUGO,
> +                               pm_genpd_debugfs_dir, NULL,
> +                               &pm_genpd_states_fops);
> +       if (d)
> +               d = debugfs_create_file("timings", S_IRUGO,
> +                               pm_genpd_debugfs_dir, NULL,
> +                               &pm_genpd_timing_fops);
> +       if (d)
> +               return 0;
>
> -       d = debugfs_create_file("pm_genpd_summary", S_IRUGO,
> -                       pm_genpd_debugfs_dir, NULL, &pm_genpd_summary_fops);
> -       if (!d)
> -               return -ENOMEM;
> +       debugfs_remove_recursive(pm_genpd_debugfs_dir /*can be null*/);
>
> -       return 0;
> +       return -ENOMEM;
>  }
>  late_initcall(pm_genpd_debug_init);
>

Kind regards
Uffe
Marc Titinger Dec. 16, 2015, 11:07 a.m. UTC | #2
On 11/12/2015 12:46, Ulf Hansson wrote:
> On 17 November 2015 at 23:37, Lina Iyer <lina.iyer@linaro.org> wrote:


Hi Ulf,

thanks for the review, comments and questions below.

Best Regards,
Marc.

>> From: Marc Titinger <mtitinger@baylibre.com>
>>
>> This purpose of these debug seq-files is to help investigate
>> generic power domain state transitions, based on device constraints.
>> requires the "multiple states" patches from Axel Haslam.
>
> This last sentence doesn't belong in the change-log, please remove it.
>
>>
>> also rename 'summary' from 'pm_genpd_summary'
>>
>> sample output for 'states'
>> ==========================
>>
>>    Domain             State name        Eval = 2200nter + Exit = Min_off_on (ns)
>> -----------------------------------------------------------------------
>> a53_pd               cluster-sleep-0      1500000+800000=2300000
>> a57_pd               d1-retention         1000000+800000=1800000
>> a57_pd               cluster-sleep-0      1500000+800000=2300000
>>
>> sample output for 'timings'
>> ===========================
>>
>>      Domain Devices, Timings in ns
>>                         Stop/Start Save/Restore, Effective
>> ----------------------------------------------------  ---
>> a53_pd
>>      /cpus/cpu@100        1060  /660    1580  /1940  ,0 (cached stop)
>>      /cpus/cpu@101        1060  /740    1520  /1600  ,0 (cached stop)
>>      /cpus/cpu@102        880   /620    1380  /1780  ,0 (cached stop)
>>      /cpus/cpu@103        1080  /640    1340  /1600  ,0 (cached stop)
>> a57_pd
>>      /cpus/cpu@0          1160  /740    3280  /1800  ,0 (cached stop)
>>      /cpus/cpu@1          780   /1400   1440  /2080  ,0 (cached stop)
>>      /D1                  600   /540    7140  /6420  ,2199460 (cached stop)
>>
>> Signed-off-by: Marc Titinger <mtitinger@baylibre.com>
>
> A general comment. Static functions in genpd shall start with one of
> the following prefix.
>
> genpd_*
> _genpd_*
> __genpd_*
>
> Please change accordingly.

Many static routines were already prefixed like the exported functions 
with "pm_", shall I make a separate patch for this renaming ?

>
>> ---
>>   drivers/base/power/domain.c | 115 +++++++++++++++++++++++++++++++++++++++++---
>>   1 file changed, 107 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>> index c300293..9a0df09 100644
>> --- a/drivers/base/power/domain.c
>> +++ b/drivers/base/power/domain.c
>> @@ -2169,21 +2169,120 @@ static const struct file_operations pm_genpd_summary_fops = {
>>          .release = single_release,
>>   };
>>
>> +static int pm_genpd_states_show(struct seq_file *s, void *data)
>> +{
>> +       struct generic_pm_domain *genpd;
>> +
>> +       seq_puts(s,
>> +                "\n  Domain             State name        Enter + Exit = Min_off_on (ns)\n");
>> +       seq_puts(s,
>> +                "-----------------------------------------------------------------------\n");
>> +
>
> You must hold the gpd_list_lock while traversing the gpd list.
>
>> +       list_for_each_entry(genpd, &gpd_list, gpd_list_node) {
>> +
>> +               int i;
>> +
>> +               for (i = 0; i < genpd->state_count; i++) {
>
> To be sure you have valid data, you should hold the genpd lock here.
>

At some point while testing with calling suspend from the power_off 
handler, the cpu would go to sleep with the lock held, hence using this 
seq-file would not work.

while I agree, I think it is not super likely that a 
domain/child/devices/states are added or removed at this point (the DT 
is parsed already), would using list_for_each_entry_safe be safe enough ?

>> +                       seq_printf(s, "%-20s %-20s %lld+%lld=%lld\n",
>> +                                  genpd->name,
>> +                                  genpd->states[i].name,
>> +                                  genpd->states[i].power_on_latency_ns,
>> +                                  genpd->states[i].power_off_latency_ns,
>> +                                  genpd->states[i].power_off_latency_ns
>> +                                  + genpd->states[i].power_on_latency_ns);
>> +               }
>> +
>> +       }
>> +
>> +       seq_puts(s, "\n");
>> +
>> +       return 0;
>> +}
>> +
>> +static int pm_genpd_states_open(struct inode *inode, struct file *file)
>> +{
>> +       return single_open(file, pm_genpd_states_show, NULL);
>> +}
>> +
>> +static const struct file_operations pm_genpd_states_fops = {
>> +       .open = pm_genpd_states_open,
>> +       .read = seq_read,
>> +       .llseek = seq_lseek,
>> +       .release = single_release,
>> +};
>> +
>> +static int pm_genpd_timing_show(struct seq_file *s, void *data)
>> +{
>> +       struct generic_pm_domain *genpd;
>> +
>> +       seq_puts(s, "\n    Domain Devices, Timings in ns\n");
>> +       seq_puts(s,
>> +                "                       Stop/Start Save/Restore, Effective\n");
>> +       seq_puts(s,
>> +                "----------------------------------------------------  ---\n");
>> +
>
> You must hold the gpd_list_lock while traversing the gpd list.
>
>
>> +       list_for_each_entry(genpd, &gpd_list, gpd_list_node) {
>> +               struct pm_domain_data *pm_data;
>> +
>> +               seq_printf(s, "%-30s", genpd->name);
>> +
>
> You must hold the genpd lock while traversing the device list.
>
>> +               list_for_each_entry(pm_data, &genpd->dev_list, list_node) {
>> +                       struct gpd_timing_data *td = &to_gpd_data(pm_data)->td;
>> +
>> +                       if (!pm_data->dev->of_node)
>> +                               continue;
>> +
>> +                       seq_printf(s,
>> +                                  "\n    %-20s %-6lld/%-6lld %-6lld/%-6lld,%lld %s%s",
>> +                                  pm_data->dev->of_node->full_name,
>> +                                  td->stop_latency_ns, td->start_latency_ns,
>> +                                  td->save_state_latency_ns,
>> +                                  td->restore_state_latency_ns,
>
> This needs a re-base as these values have been merged.
>
>> +                                  td->effective_constraint_ns,
>> +                                  td->cached_stop_ok ? "(cached stop) " : "",
>> +                                  td->constraint_changed ? "(changed)" : "");
>> +               }
>> +               seq_puts(s, "\n");
>> +       }
>> +       return 0;
>> +}
>> +
>> +static int pm_genpd_timing_open(struct inode *inode, struct file *file)
>> +{
>> +       return single_open(file, pm_genpd_timing_show, NULL);
>> +}
>> +
>> +static const struct file_operations pm_genpd_timing_fops = {
>> +       .open = pm_genpd_timing_open,
>> +       .read = seq_read,
>> +       .llseek = seq_lseek,
>> +       .release = single_release,
>> +};
>> +
>>   static int __init pm_genpd_debug_init(void)
>>   {
>> -       struct dentry *d;
>> +       struct dentry *d = NULL;
>>
>>          pm_genpd_debugfs_dir = debugfs_create_dir("pm_genpd", NULL);
>>
>> -       if (!pm_genpd_debugfs_dir)
>> -               return -ENOMEM;
>> +       if (pm_genpd_debugfs_dir)
>
> In case when CONFIG_DEBUG_FS is unset, this doesn't work very well, as
> pm_genpd_debugfs_dir will contain an error code.
>
> Since you are anyway make quite big change to the debugfs support for
> genpd, perhaps you can try to fix that up as well!?

Ah yes ok, will do.

>
>> +               d = debugfs_create_file("summary", S_IRUGO,
>> +                               pm_genpd_debugfs_dir, NULL,
>> +                               &pm_genpd_summary_fops);
>> +       if (d)
>> +               d = debugfs_create_file("states", S_IRUGO,
>> +                               pm_genpd_debugfs_dir, NULL,
>> +                               &pm_genpd_states_fops);
>> +       if (d)
>> +               d = debugfs_create_file("timings", S_IRUGO,
>> +                               pm_genpd_debugfs_dir, NULL,
>> +                               &pm_genpd_timing_fops);
>> +       if (d)
>> +               return 0;
>>
>> -       d = debugfs_create_file("pm_genpd_summary", S_IRUGO,
>> -                       pm_genpd_debugfs_dir, NULL, &pm_genpd_summary_fops);
>> -       if (!d)
>> -               return -ENOMEM;
>> +       debugfs_remove_recursive(pm_genpd_debugfs_dir /*can be null*/);
>>
>> -       return 0;
>> +       return -ENOMEM;
>>   }
>>   late_initcall(pm_genpd_debug_init);
>>
>
> Kind regards
> Uffe
>
Ulf Hansson Dec. 16, 2015, 12:48 p.m. UTC | #3
[...]

>>
>> A general comment. Static functions in genpd shall start with one of
>> the following prefix.
>>
>> genpd_*
>> _genpd_*
>> __genpd_*
>>
>> Please change accordingly.
>
>
> Many static routines were already prefixed like the exported functions with
> "pm_", shall I make a separate patch for this renaming ?

My point is that I don't want it to becomes worse.

If you follow the above rule for new changes, I am happy.

Whether you want to send a separate patch fixing the other existing
name to be consistent with above rule, I would also be happy. :-)

>
>
>>
>>> ---
>>>   drivers/base/power/domain.c | 115
>>> +++++++++++++++++++++++++++++++++++++++++---
>>>   1 file changed, 107 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>>> index c300293..9a0df09 100644
>>> --- a/drivers/base/power/domain.c
>>> +++ b/drivers/base/power/domain.c
>>> @@ -2169,21 +2169,120 @@ static const struct file_operations
>>> pm_genpd_summary_fops = {
>>>          .release = single_release,
>>>   };
>>>
>>> +static int pm_genpd_states_show(struct seq_file *s, void *data)
>>> +{
>>> +       struct generic_pm_domain *genpd;
>>> +
>>> +       seq_puts(s,
>>> +                "\n  Domain             State name        Enter + Exit =
>>> Min_off_on (ns)\n");
>>> +       seq_puts(s,
>>> +
>>> "-----------------------------------------------------------------------\n");
>>> +
>>
>>
>> You must hold the gpd_list_lock while traversing the gpd list.
>>
>>> +       list_for_each_entry(genpd, &gpd_list, gpd_list_node) {
>>> +
>>> +               int i;
>>> +
>>> +               for (i = 0; i < genpd->state_count; i++) {
>>
>>
>> To be sure you have valid data, you should hold the genpd lock here.
>>
>
> At some point while testing with calling suspend from the power_off handler,
> the cpu would go to sleep with the lock held, hence using this seq-file
> would not work.

That seems like a bad behaviour during suspend. Why does it hold the lock?

On the other it shouldn't matter as userspace can't access the debugfs
nodes, since its frozen at those times, right!?

>
> while I agree, I think it is not super likely that a
> domain/child/devices/states are added or removed at this point (the DT is
> parsed already), would using list_for_each_entry_safe be safe enough ?

No it's not.

The gpd_list is protected with the gdp_list_lock, which is needed
because new genpds can be added at any point.

You also need the genpd lock here, as otherwise you may print the
latency-values in the middle of when these are being updated.

>
>
>>> +                       seq_printf(s, "%-20s %-20s %lld+%lld=%lld\n",
>>> +                                  genpd->name,
>>> +                                  genpd->states[i].name,
>>> +                                  genpd->states[i].power_on_latency_ns,
>>> +                                  genpd->states[i].power_off_latency_ns,
>>> +                                  genpd->states[i].power_off_latency_ns
>>> +                                  +
>>> genpd->states[i].power_on_latency_ns);
>>> +               }
>>> +
>>> +       }
>>> +
>>> +       seq_puts(s, "\n");
>>> +
>>> +       return 0;
>>> +}
>>> +

[...]

Kind regards
Uffe
Marc Titinger Dec. 16, 2015, 2:12 p.m. UTC | #4
On 16/12/2015 13:48, Ulf Hansson wrote:
> [...]
>
>>>
>>> A general comment. Static functions in genpd shall start with one of
>>> the following prefix.
>>>
>>> genpd_*
>>> _genpd_*
>>> __genpd_*
>>>
>>> Please change accordingly.
>>
>>
>> Many static routines were already prefixed like the exported functions with
>> "pm_", shall I make a separate patch for this renaming ?
>
> My point is that I don't want it to becomes worse.
>
> If you follow the above rule for new changes, I am happy.
>
> Whether you want to send a separate patch fixing the other existing
> name to be consistent with above rule, I would also be happy. :-)

Fair enough, I'll do a renaming patch :)

>
>>
>>
>>>
>>>> ---
>>>>    drivers/base/power/domain.c | 115
>>>> +++++++++++++++++++++++++++++++++++++++++---
>>>>    1 file changed, 107 insertions(+), 8 deletions(-)
>>>>
>>>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>>>> index c300293..9a0df09 100644
>>>> --- a/drivers/base/power/domain.c
>>>> +++ b/drivers/base/power/domain.c
>>>> @@ -2169,21 +2169,120 @@ static const struct file_operations
>>>> pm_genpd_summary_fops = {
>>>>           .release = single_release,
>>>>    };
>>>>
>>>> +static int pm_genpd_states_show(struct seq_file *s, void *data)
>>>> +{
>>>> +       struct generic_pm_domain *genpd;
>>>> +
>>>> +       seq_puts(s,
>>>> +                "\n  Domain             State name        Enter + Exit =
>>>> Min_off_on (ns)\n");
>>>> +       seq_puts(s,
>>>> +
>>>> "-----------------------------------------------------------------------\n");
>>>> +
>>>
>>>
>>> You must hold the gpd_list_lock while traversing the gpd list.
>>>
>>>> +       list_for_each_entry(genpd, &gpd_list, gpd_list_node) {
>>>> +
>>>> +               int i;
>>>> +
>>>> +               for (i = 0; i < genpd->state_count; i++) {
>>>
>>>
>>> To be sure you have valid data, you should hold the genpd lock here.
>>>
>>
>> At some point while testing with calling suspend from the power_off handler,
>> the cpu would go to sleep with the lock held, hence using this seq-file
>> would not work.
>
> That seems like a bad behaviour during suspend. Why does it hold the lock?

that was in the scenario where 2 or more cpus are devices of the same 
power domain. IIRC you would have something like:

arm_enter_idle_state(cpu)
	pm_runtime_put_sync
		rpm_suspend
		__rpm_get_callback
			pm_genpd_runtime_suspend
				[Take lock]
				->platform code to enter sleep...

and race condition with another cpu of the same cluster trying to 
suspend or resume at the same time. it is a bad behaviour, I cannot test
the os-initiated mode here but I assume this is done differently and is 
no longer an issue (sorry for not being more specific).

>
> On the other it shouldn't matter as userspace can't access the debugfs
> nodes, since its frozen at those times, right!?

you can have cpu_j off, and cpu_i running the shell, in the scenario 
above. But since this was while hacking calling psci from 
genpd.power_off, I'm not sure it's worth mentioning...

>
>>
>> while I agree, I think it is not super likely that a
>> domain/child/devices/states are added or removed at this point (the DT is
>> parsed already), would using list_for_each_entry_safe be safe enough ?
>
> No it's not.
>
> The gpd_list is protected with the gdp_list_lock, which is needed
> because new genpds can be added at any point.
>
> You also need the genpd lock here, as otherwise you may print the
> latency-values in the middle of when these are being updated.

Understood, I'll put the lock back.

>
>>
>>
>>>> +                       seq_printf(s, "%-20s %-20s %lld+%lld=%lld\n",
>>>> +                                  genpd->name,
>>>> +                                  genpd->states[i].name,
>>>> +                                  genpd->states[i].power_on_latency_ns,
>>>> +                                  genpd->states[i].power_off_latency_ns,
>>>> +                                  genpd->states[i].power_off_latency_ns
>>>> +                                  +
>>>> genpd->states[i].power_on_latency_ns);
>>>> +               }
>>>> +
>>>> +       }
>>>> +
>>>> +       seq_puts(s, "\n");
>>>> +
>>>> +       return 0;
>>>> +}
>>>> +
>
> [...]
>
> Kind regards
> Uffe
>
diff mbox

Patch

==========================

  Domain             State name        Eval = 2200nter + Exit = Min_off_on (ns)
-----------------------------------------------------------------------
a53_pd               cluster-sleep-0      1500000+800000=2300000
a57_pd               d1-retention         1000000+800000=1800000
a57_pd               cluster-sleep-0      1500000+800000=2300000

sample output for 'timings'
===========================

    Domain Devices, Timings in ns
                       Stop/Start Save/Restore, Effective
----------------------------------------------------  ---
a53_pd
    /cpus/cpu@100        1060  /660    1580  /1940  ,0 (cached stop)
    /cpus/cpu@101        1060  /740    1520  /1600  ,0 (cached stop)
    /cpus/cpu@102        880   /620    1380  /1780  ,0 (cached stop)
    /cpus/cpu@103        1080  /640    1340  /1600  ,0 (cached stop)
a57_pd
    /cpus/cpu@0          1160  /740    3280  /1800  ,0 (cached stop)
    /cpus/cpu@1          780   /1400   1440  /2080  ,0 (cached stop)
    /D1                  600   /540    7140  /6420  ,2199460 (cached stop)

Signed-off-by: Marc Titinger <mtitinger@baylibre.com>
---
 drivers/base/power/domain.c | 115 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 107 insertions(+), 8 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index c300293..9a0df09 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2169,21 +2169,120 @@  static const struct file_operations pm_genpd_summary_fops = {
 	.release = single_release,
 };
 
+static int pm_genpd_states_show(struct seq_file *s, void *data)
+{
+	struct generic_pm_domain *genpd;
+
+	seq_puts(s,
+		 "\n  Domain             State name        Enter + Exit = Min_off_on (ns)\n");
+	seq_puts(s,
+		 "-----------------------------------------------------------------------\n");
+
+	list_for_each_entry(genpd, &gpd_list, gpd_list_node) {
+
+		int i;
+
+		for (i = 0; i < genpd->state_count; i++) {
+			seq_printf(s, "%-20s %-20s %lld+%lld=%lld\n",
+				   genpd->name,
+				   genpd->states[i].name,
+				   genpd->states[i].power_on_latency_ns,
+				   genpd->states[i].power_off_latency_ns,
+				   genpd->states[i].power_off_latency_ns
+				   + genpd->states[i].power_on_latency_ns);
+		}
+
+	}
+
+	seq_puts(s, "\n");
+
+	return 0;
+}
+
+static int pm_genpd_states_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pm_genpd_states_show, NULL);
+}
+
+static const struct file_operations pm_genpd_states_fops = {
+	.open = pm_genpd_states_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static int pm_genpd_timing_show(struct seq_file *s, void *data)
+{
+	struct generic_pm_domain *genpd;
+
+	seq_puts(s, "\n    Domain Devices, Timings in ns\n");
+	seq_puts(s,
+		 "                       Stop/Start Save/Restore, Effective\n");
+	seq_puts(s,
+		 "----------------------------------------------------  ---\n");
+
+	list_for_each_entry(genpd, &gpd_list, gpd_list_node) {
+		struct pm_domain_data *pm_data;
+
+		seq_printf(s, "%-30s", genpd->name);
+
+		list_for_each_entry(pm_data, &genpd->dev_list, list_node) {
+			struct gpd_timing_data *td = &to_gpd_data(pm_data)->td;
+
+			if (!pm_data->dev->of_node)
+				continue;
+
+			seq_printf(s,
+				   "\n    %-20s %-6lld/%-6lld %-6lld/%-6lld,%lld %s%s",
+				   pm_data->dev->of_node->full_name,
+				   td->stop_latency_ns, td->start_latency_ns,
+				   td->save_state_latency_ns,
+				   td->restore_state_latency_ns,
+				   td->effective_constraint_ns,
+				   td->cached_stop_ok ? "(cached stop) " : "",
+				   td->constraint_changed ? "(changed)" : "");
+		}
+		seq_puts(s, "\n");
+	}
+	return 0;
+}
+
+static int pm_genpd_timing_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pm_genpd_timing_show, NULL);
+}
+
+static const struct file_operations pm_genpd_timing_fops = {
+	.open = pm_genpd_timing_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
 static int __init pm_genpd_debug_init(void)
 {
-	struct dentry *d;
+	struct dentry *d = NULL;
 
 	pm_genpd_debugfs_dir = debugfs_create_dir("pm_genpd", NULL);
 
-	if (!pm_genpd_debugfs_dir)
-		return -ENOMEM;
+	if (pm_genpd_debugfs_dir)
+		d = debugfs_create_file("summary", S_IRUGO,
+				pm_genpd_debugfs_dir, NULL,
+				&pm_genpd_summary_fops);
+	if (d)
+		d = debugfs_create_file("states", S_IRUGO,
+				pm_genpd_debugfs_dir, NULL,
+				&pm_genpd_states_fops);
+	if (d)
+		d = debugfs_create_file("timings", S_IRUGO,
+				pm_genpd_debugfs_dir, NULL,
+				&pm_genpd_timing_fops);
+	if (d)
+		return 0;
 
-	d = debugfs_create_file("pm_genpd_summary", S_IRUGO,
-			pm_genpd_debugfs_dir, NULL, &pm_genpd_summary_fops);
-	if (!d)
-		return -ENOMEM;
+	debugfs_remove_recursive(pm_genpd_debugfs_dir /*can be null*/);
 
-	return 0;
+	return -ENOMEM;
 }
 late_initcall(pm_genpd_debug_init);