[PATCH 2/3] pmdomain: Add support for system-suspend-only states

[Maulik Shah]

Some domain idle states require system-wide coordination and should not be
selected during regular CPU idle. However those states remain valid for
system-wide suspend like s2idle.

Add a per-state system_state boolean and populate it from the system-state
property. Make the genpd governor skip these states during CPU idle. Leave
the system wide suspend path unchanged so s2idle can select them.

Assisted-by: Codex:GPT-6
Signed-off-by: Maulik Shah <maulik.shah@xxxxxxxxxxxxxxxx>
---
 drivers/pmdomain/core.c     | 2 ++
 drivers/pmdomain/governor.c | 6 ++++++
 include/linux/pm_domain.h   | 1 +
 3 files changed, 9 insertions(+)

diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index 964e44c2f78f..288c0deb2340 100644
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -3701,6 +3701,8 @@ static int genpd_parse_state(struct genpd_power_state *genpd_state,
 	if (!err)
 		genpd_state->residency_ns = 1000LL * residency;
 
+	genpd_state->system_state = of_property_read_bool(state_node, "system-state");
+
 	err = of_property_read_string(state_node, "idle-state-name",
 				      &genpd_state->name);
 	if (err)
diff --git a/drivers/pmdomain/governor.c b/drivers/pmdomain/governor.c
index 38bba24ec26e..7684f9eecf85 100644
--- a/drivers/pmdomain/governor.c
+++ b/drivers/pmdomain/governor.c
@@ -185,6 +185,9 @@ static bool __default_power_down_ok(struct dev_pm_domain *pd,
 	s64 min_off_time_ns;
 	s64 off_on_time_ns;
 
+	if (genpd->states[state].system_state)
+		return false;
+
 	off_on_time_ns = genpd->states[state].power_off_latency_ns +
 		genpd->states[state].power_on_latency_ns;
 
@@ -407,6 +410,9 @@ static bool cpu_power_down_ok(struct dev_pm_domain *pd)
 	 */
 	i = genpd->state_idx;
 	do {
+		if (genpd->states[i].system_state)
+			continue;
+
 		if ((idle_duration_ns >= (genpd->states[i].residency_ns +
 		    genpd->states[i].power_off_latency_ns)) &&
 		    (global_constraint >= (genpd->states[i].power_on_latency_ns +
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 14e0e346c610..d9b3e67042e5 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -188,6 +188,7 @@ struct genpd_power_state {
 	s64 power_off_latency_ns;
 	s64 power_on_latency_ns;
 	s64 residency_ns;
+	bool system_state;
 	u64 usage;
 	u64 rejected;
 	u64 above;

-- 
2.43.0