linux-kernel - [PATCH 3/3] pmdomain: core: Extend statistics for domain idle states with s2idle data

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Message-ID: <20260119143121.161583-4-ulf.hansson@linaro.org>
Date: Mon, 19 Jan 2026 15:31:15 +0100
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Ulf Hansson <ulf.hansson@...aro.org>,
	Dhruva Gole <d-gole@...com>,
	linux-pm@...r.kernel.org
Cc: "Rafael J . Wysocki" <rafael@...nel.org>,
	Kevin Hilman <khilman@...libre.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] pmdomain: core: Extend statistics for domain idle states with s2idle data

To allow user space to monitor the selection of the domain idle state
during s2idle for a CPU PM domain, let's extend the debugfs support in
genpd with this information.

Suggested-by: Dhruva Gole <d-gole@...com>
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
---
 drivers/pmdomain/core.c   | 13 ++++++++++---
 include/linux/pm_domain.h |  1 +
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index bf512ff0857d..bb04cb7ccdcd 100644
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -1438,6 +1438,13 @@ static void genpd_sync_power_off(struct generic_pm_domain *genpd, bool use_lock,
 		return;
 	} else {
 		genpd->states[genpd->state_idx].usage++;
+
+		/*
+		 * The ->system_power_down_ok() callback is currently used only
+		 * for s2idle. Use it to know when to update the usage counter.
+		 */
+		if (genpd->gov && genpd->gov->system_power_down_ok)
+			genpd->states[genpd->state_idx].usage_s2idle++;
 	}
 
 	genpd->status = GENPD_STATE_OFF;
@@ -3772,7 +3779,7 @@ static int idle_states_show(struct seq_file *s, void *data)
 	if (ret)
 		return -ERESTARTSYS;
 
-	seq_puts(s, "State  Time(ms)       Usage      Rejected   Above      Below\n");
+	seq_puts(s, "State  Time(ms)       Usage      Rejected   Above      Below      S2idle\n");
 
 	for (i = 0; i < genpd->state_count; i++) {
 		struct genpd_power_state *state = &genpd->states[i];
@@ -3790,9 +3797,9 @@ static int idle_states_show(struct seq_file *s, void *data)
 
 		snprintf(state_name, ARRAY_SIZE(state_name), "S%-5d", i);
 		do_div(idle_time, NSEC_PER_MSEC);
-		seq_printf(s, "%-6s %-14llu %-10llu %-10llu %-10llu %llu\n",
+		seq_printf(s, "%-6s %-14llu %-10llu %-10llu %-10llu %-10llu %llu\n",
 			   state_name, idle_time, state->usage, state->rejected,
-			   state->above, state->below);
+			   state->above, state->below, state->usage_s2idle);
 	}
 
 	genpd_unlock(genpd);
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 93ba0143ca47..f6f6d494f728 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -183,6 +183,7 @@ struct genpd_power_state {
 	u64 rejected;
 	u64 above;
 	u64 below;
+	u64 usage_s2idle;
 	struct fwnode_handle *fwnode;
 	u64 idle_time;
 	void *data;
-- 
2.43.0