[PATCH v3] PM / Domains: enable domain idle state accounting

[Lina Iyer <ilina@xxxxxxxxxxxxxx>]

To enable better debug of PM domains, let's keep a track of the success
and rejections in entering each domain idle state.

This statistics is exported in debugfs when reading the idle_states
node, associated with each PM domain.

Signed-off-by: Lina Iyer <ilina@xxxxxxxxxxxxxx>
---
Changes in v3:
	- Rebased on top of mainline
---
 drivers/base/power/domain.c | 10 +++++++---
 include/linux/pm_domain.h   |  2 ++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 2cb5e04cf86c..20ecc1a7113c 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -559,12 +559,15 @@ static int genpd_power_off(struct generic_pm_domain *genpd, bool one_dev_on,
 		 * happen very often).
 		 */
 		ret = _genpd_power_off(genpd, true);
-		if (ret)
+		if (ret) {
+			genpd->states[genpd->state_idx].rejected++;
 			return ret;
+		}
 	}
 
 	genpd->status = GPD_STATE_POWER_OFF;
 	genpd_update_accounting(genpd);
+	genpd->states[genpd->state_idx].usage++;
 
 	list_for_each_entry(link, &genpd->child_links, child_node) {
 		genpd_sd_counter_dec(link->parent);
@@ -2932,7 +2935,7 @@ static int idle_states_show(struct seq_file *s, void *data)
 	if (ret)
 		return -ERESTARTSYS;
 
-	seq_puts(s, "State          Time Spent(ms)\n");
+	seq_puts(s, "State          Time Spent(ms) Usage          Rejected\n");
 
 	for (i = 0; i < genpd->state_count; i++) {
 		ktime_t delta = 0;
@@ -2944,7 +2947,8 @@ static int idle_states_show(struct seq_file *s, void *data)
 
 		msecs = ktime_to_ms(
 			ktime_add(genpd->states[i].idle_time, delta));
-		seq_printf(s, "S%-13i %lld\n", i, msecs);
+		seq_printf(s, "S%-13i %-14lld %-14llu %llu\n", i, msecs,
+			      genpd->states[i].usage, genpd->states[i].rejected);
 	}
 
 	genpd_unlock(genpd);
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index ee11502a575b..1d9a8de6b7ac 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -82,6 +82,8 @@ struct genpd_power_state {
 	s64 power_off_latency_ns;
 	s64 power_on_latency_ns;
 	s64 residency_ns;
+	u64 usage;
+	u64 rejected;
 	struct fwnode_handle *fwnode;
 	ktime_t idle_time;
 	void *data;
-- 
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