RE: [PATCH v4 1/3] PM: wakeup: Add routine to help fetch wakeup source object.

Ran Wang
2019-06-19T09:36:27Z

Hi Rafael,

On Wednesday, June 19, 2019 06:45, Rafael J. Wysocki wrote:
>
> On Monday, May 20, 2019 11:52:36 AM CEST Ran Wang wrote:
> > Some user might want to go through all registered wakeup sources and
> > doing things accordingly. For example, SoC PM driver might need to do
> > HW programming to prevent powering down specific IP which wakeup
> > source depending on. And is user's responsibility to identify if this
> > wakeup source he is interested in.
>
> I guess the idea here is that you need to walk wakeup devices and you noticed
> that there was a wakeup source object for each of them and those wakeup
> source objects were on a list, so you could walk wakeup devices by walking the
> list of wakeup source objects.
>
> That is fair enough, but the changelog above doesn't even talk about that.

How about this:
"Providing a API for helping walk through all registered wakeup devices on the list.
It will be useful for SoC PMU driver to know which device will work as a wakeup
source then do specific HW programming for them."

> > Signed-off-by: Ran Wang <ran.wang_1@nxp.com>
> > ---
> > Change in v4:
> > - None.
> >
> > Change in v3:
> > - Adjust indentation of *attached_dev;.
> >
> > Change in v2:
> > - None.
> >
> > drivers/base/power/wakeup.c | 18 ++++++++++++++++++
> > include/linux/pm_wakeup.h | 3 +++
> > 2 files changed, 21 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
> > index 5b2b6a0..6904485 100644
> > --- a/drivers/base/power/wakeup.c
> > +++ b/drivers/base/power/wakeup.c
> > @@ -14,6 +14,7 @@
> > #include <linux/suspend.h>
> > #include <linux/seq_file.h>
> > #include <linux/debugfs.h>
> > +#include <linux/of_device.h>
> > #include <linux/pm_wakeirq.h>
> > #include <trace/events/power.h>
> >
> > @@ -226,6 +227,22 @@ void wakeup_source_unregister(struct
> wakeup_source *ws)
> > }
> > }
> > EXPORT_SYMBOL_GPL(wakeup_source_unregister);
> > +/**
> > + * wakeup_source_get_next - Get next wakeup source from the list
> > + * @ws: Previous wakeup source object, null means caller want first one.
> > + */
> > +struct wakeup_source *wakeup_source_get_next(struct wakeup_source
> > +*ws) {
> > + struct list_head *ws_head = &wakeup_sources;
> > +
> > + if (ws)
> > + return list_next_or_null_rcu(ws_head, &ws->entry,
> > + struct wakeup_source, entry);
> > + else
> > + return list_entry_rcu(ws_head->next,
> > + struct wakeup_source, entry);
> > +}
> > +EXPORT_SYMBOL_GPL(wakeup_source_get_next);
>
> This needs to be arranged along the lines of
> wakeup_sources_stats_seq_start/next/stop()
> because of the SRCU protection of the list.

Got it, how about this:
230 /**
231 * wakeup_source_get_next - Get next wakeup source from the list
232 * @ws: Previous wakeup source object, null means caller want first one.
233 */
234 struct wakeup_source *wakeup_source_get_next(struct wakeup_source *ws)
235 {
236 struct list_head *ws_head = &wakeup_sources;
237 struct wakeup_source *next_ws = NULL;
238 int idx;
239
240 idx = srcu_read_lock(&wakeup_srcu);
241 if (ws)
242 next_ws = list_next_or_null_rcu(ws_head, &ws->entry,
243 struct wakeup_source, entry);
244 else
245 next_ws = list_entry_rcu(ws_head->next,
246 struct wakeup_source, entry);
247 srcu_read_unlock(&wakeup_srcu, idx);
248
249 return next_ws;
250 }
251 EXPORT_SYMBOL_GPL(wakeup_source_get_next);

> >
> > /**
> > * device_wakeup_attach - Attach a wakeup source object to a device object.
> > @@ -242,6 +259,7 @@ static int device_wakeup_attach(struct device *dev,
> struct wakeup_source *ws)
> > return -EEXIST;
> > }
> > dev->power.wakeup = ws;
> > + ws->attached_dev = dev;
> > if (dev->power.wakeirq)
> > device_wakeup_attach_irq(dev, dev->power.wakeirq);
> > spin_unlock_irq(&dev->power.lock);
> > diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
> > index 0ff134d..913b2fb 100644
> > --- a/include/linux/pm_wakeup.h
> > +++ b/include/linux/pm_wakeup.h
> > @@ -50,6 +50,7 @@
> > * @wakeup_count: Number of times the wakeup source might abort suspend.
> > * @active: Status of the wakeup source.
> > * @has_timeout: The wakeup source has been activated with a timeout.
> > + * @attached_dev: The device it attached to
> > */
> > struct wakeup_source {
> > const char *name;
> > @@ -70,6 +71,7 @@ struct wakeup_source {
> > unsigned long wakeup_count;
> > bool active:1;
> > bool autosleep_enabled:1;
> > + struct device *attached_dev;
>
> Please (a) call it just dev and (b) move it up (before wakeirq, say)

Got it, will update in next version.

Thanks & Regards,
Ran
>
> > };
> >
> > #ifdef CONFIG_PM_SLEEP
> > @@ -101,6 +103,7 @@ static inline void device_set_wakeup_path(struct
> > device *dev) extern void wakeup_source_remove(struct wakeup_source
> > *ws); extern struct wakeup_source *wakeup_source_register(const char
> > *name); extern void wakeup_source_unregister(struct wakeup_source
> > *ws);
> > +extern struct wakeup_source *wakeup_source_get_next(struct
> > +wakeup_source *ws);
> > extern int device_wakeup_enable(struct device *dev); extern int
> > device_wakeup_disable(struct device *dev); extern void
> > device_set_wakeup_capable(struct device *dev, bool capable);
> >
>
>
>