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

Rafael J. Wysocki
2019-06-18T22:44:44Z

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.

> 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.

>
> /**
> * 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).

> };
>
> #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);
>