cpuidle: riscv-sbi: Drop redundant sync_state support

The recent updates to the genpd core, can entirely manage the sync_state
support for the cpuidle-riscv-sbi-domain. More precisely, genpd prevents
our ->power_off() callback from being invoked, until all of our consumers
are ready for it.

Let's therefore drop the sync_state support for the
cpuidle-riscv-sbi-domain as it has become redundant.

Cc: Anup Patel <anup@brainfault.org>
Cc: linux-riscv@lists.infradead.org
Tested-by: Hiago De Franco <hiago.franco@toradex.com> # Colibri iMX8X
Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> # TI AM62A,Xilinx ZynqMP ZCU106
Reviewed-by: Rahul Pathak <rpathak@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20250701114733.636510-25-ulf.hansson@linaro.org

Author: Ulf Hansson

drivers/cpuidle/cpuidle-riscv-sbi.c

@@ -44,7 +44,6 @@ static DEFINE_PER_CPU_READ_MOSTLY(struct sbi_cpuidle_data, sbi_cpuidle_data);
 static DEFINE_PER_CPU(struct sbi_domain_state, domain_state);
 static bool sbi_cpuidle_use_osi;
 static bool sbi_cpuidle_use_cpuhp;
-static bool sbi_cpuidle_pd_allow_domain_state;
 
 static inline void sbi_set_domain_state(u32 state)
 {
@@ -345,20 +344,6 @@ static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
 	return ret;
 }
 
-static void sbi_cpuidle_domain_sync_state(struct device *dev)
-{
-	struct sbi_pd_provider *pd_provider;
-
-	/*
-	 * All devices have now been attached/probed to the PM domain
-	 * topology, hence it's fine to allow domain states to be picked.
-	 */
-	sbi_cpuidle_pd_allow_domain_state = true;
-
-	list_for_each_entry(pd_provider, &sbi_pd_providers, link)
-		of_genpd_sync_state(pd_provider->node);
-}
-
 #ifdef CONFIG_DT_IDLE_GENPD
 
 static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
@@ -369,9 +354,6 @@ static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
 	if (!state->data)
 		return 0;
 
-	if (!sbi_cpuidle_pd_allow_domain_state)
-		return -EBUSY;
-
 	/* OSI mode is enabled, set the corresponding domain state. */
 	pd_state = state->data;
 	sbi_set_domain_state(*pd_state);
@@ -401,8 +383,7 @@ static int sbi_pd_init(struct device_node *np)
 	if (!pd_provider)
 		goto free_pd;
 
-	pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN |
-		     GENPD_FLAG_NO_SYNC_STATE;
+	pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
 
 	/* Allow power off when OSI is available. */
 	if (sbi_cpuidle_use_osi)
@@ -570,7 +551,6 @@ static struct platform_driver sbi_cpuidle_driver = {
 	.probe = sbi_cpuidle_probe,
 	.driver = {
 		.name = "sbi-cpuidle",
-		.sync_state = sbi_cpuidle_domain_sync_state,
 	},
 };