[PATCH v10 01/27] PM / Domains: Add generic data pointer to genpd_power_state struct

[Ulf Hansson <ulf.hansson@linaro.org>]

Let's add a data pointer to the genpd_power_state struct, to allow a genpd
backend driver to store per state specific data. In order to introduce the
pointer, we also need to adopt how genpd frees the allocated data for the
default genpd_power_state struct, that it may allocate at pm_genpd_init().

More precisely, let's use an internal genpd flag to understand when the
states needs to be freed by genpd. When freeing the states data in
genpd_remove(), let's also clear the corresponding genpd->states pointer
and reset the genpd->state_count. In this way, a genpd backend driver
becomes aware of when there is state specific data for it to free.

Cc: Lina Iyer <ilina@codeaurora.org>
Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---

Changes in v10:
	- Update the patch allow backend drivers to free the states specific
	  data during genpd removal. Due to this added complexity, I decided to
	  keep the patch separate, rather than fold it into the patch that makes
	  use of the new void pointer, which was suggested by Rafael.
	- Claim authorship of the patch as lots of changes has been done since
	  the original pick up from Lina Iyer.

---
 drivers/base/power/domain.c | 8 ++++++--
 include/linux/pm_domain.h   | 3 ++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 7f38a92b444a..e27b91d36a2a 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1620,7 +1620,7 @@ static int genpd_set_default_power_state(struct generic_pm_domain *genpd)
 
 	genpd->states = state;
 	genpd->state_count = 1;
-	genpd->free = state;
+	genpd->free_state = true;
 
 	return 0;
 }
@@ -1736,7 +1736,11 @@ static int genpd_remove(struct generic_pm_domain *genpd)
 	list_del(&genpd->gpd_list_node);
 	genpd_unlock(genpd);
 	cancel_work_sync(&genpd->power_off_work);
-	kfree(genpd->free);
+	if (genpd->free_state) {
+		kfree(genpd->states);
+		genpd->states = NULL;
+		genpd->state_count = 0;
+	}
 	pr_debug("%s: removed %s\n", __func__, genpd->name);
 
 	return 0;
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 3b5d7280e52e..f9e09bd4152c 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -69,6 +69,7 @@ struct genpd_power_state {
 	s64 residency_ns;
 	struct fwnode_handle *fwnode;
 	ktime_t idle_time;
+	void *data;
 };
 
 struct genpd_lock_ops;
@@ -110,7 +111,7 @@ struct generic_pm_domain {
 	struct genpd_power_state *states;
 	unsigned int state_count; /* number of states */
 	unsigned int state_idx; /* state that genpd will go to when off */
-	void *free; /* Free the state that was allocated for default */
+	bool free_state; /* Free the state that was allocated for default */
 	ktime_t on_time;
 	ktime_t accounting_time;
 	const struct genpd_lock_ops *lock_ops;
-- 
2.17.1