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

[Lina Iyer <ilina@codeaurora.org>]

To enable better debug of PM domains, let's keep a track of the success
and failures 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@codeaurora.org>

---
This patch depends-on: https://lkml.org/lkml/2020/9/24/465
---
 drivers/base/power/domain.c | 7 +++++--
 include/linux/pm_domain.h   | 2 ++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index f001ac6326fb..ba3355f935da 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -564,6 +564,7 @@ static int genpd_power_off(struct generic_pm_domain *genpd, bool one_dev_on,
 
 	genpd->status = GENPD_STATE_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);
@@ -574,6 +575,7 @@ static int genpd_power_off(struct generic_pm_domain *genpd, bool one_dev_on,
 
 	return 0;
 busy:
+	genpd->states[genpd->state_idx].failed++;
 	if (nr_calls)
 		__raw_notifier_call_chain(&genpd->power_notifiers,
 					  GENPD_STATE_ON, NULL,
@@ -3053,7 +3055,7 @@ 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          Failed\n");
 
 	for (i = 0; i < genpd->state_count; i++) {
 		ktime_t delta = 0;
@@ -3065,7 +3067,8 @@ 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].failed);
 	}
 
 	genpd_unlock(genpd);
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 3b2b561ce846..c30994ec0cec 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 failed;
 	struct fwnode_handle *fwnode;
 	ktime_t idle_time;
 	void *data;
-- 
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