Commit 4517b1c3 authored by Ulf Hansson's avatar Ulf Hansson
Browse files

cpuidle: psci: Enable the hierarchical topology for s2ram on PREEMPT_RT 



The hierarchical PM domain topology are currently disabled on a PREEMPT_RT
based configuration. As a first step to enable it to be used, let's try to
attach the CPU devices to their PM domains on PREEMPT_RT. In this way the
syscore ops becomes available, allowing the PM domain topology to be
managed during s2ram.

For the moment let's leave the support for CPU hotplug outside PREEMPT_RT,
as it's depending on using runtime PM. For s2ram, this isn't a problem as
all CPUs are managed via the syscore ops.

Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Tested-by: Raghavendra Kakarla <quic_rkakarla@quicinc.com>  # qcm6490 with PREEMPT_RT set
Acked-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240527142557.321610-7-ulf.hansson@linaro.org
parent 88bf68b7

drivers/cpuidle/cpuidle-psci.c

+15 −5
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ struct psci_cpuidle_data { 


static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data);

static DEFINE_PER_CPU(u32, domain_state);

static bool psci_cpuidle_use_syscore;

static bool psci_cpuidle_use_cpuhp;



void psci_set_domain_state(u32 state)
@@ -166,6 +167,12 @@ static struct syscore_ops psci_idle_syscore_ops = { 
	.resume = psci_idle_syscore_resume,

};



static void psci_idle_init_syscore(void)

{

	if (psci_cpuidle_use_syscore)

		register_syscore_ops(&psci_idle_syscore_ops);

}



static void psci_idle_init_cpuhp(void)

{

	int err;
@@ -173,8 +180,6 @@ static void psci_idle_init_cpuhp(void) 
	if (!psci_cpuidle_use_cpuhp)

		return;



	register_syscore_ops(&psci_idle_syscore_ops);



	err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,

					"cpuidle/psci:online",

					psci_idle_cpuhp_up,
@@ -222,13 +227,16 @@ static int psci_dt_cpu_init_topology(struct cpuidle_driver *drv, 
	if (!psci_has_osi_support())

		return 0;



	if (IS_ENABLED(CONFIG_PREEMPT_RT))

		return 0;



	data->dev = dt_idle_attach_cpu(cpu, "psci");

	if (IS_ERR_OR_NULL(data->dev))

		return PTR_ERR_OR_ZERO(data->dev);



	psci_cpuidle_use_syscore = true;



	/* The hierarchical topology is limited to s2ram on PREEMPT_RT. */

	if (IS_ENABLED(CONFIG_PREEMPT_RT))

		return 0;



	/*

	 * Using the deepest state for the CPU to trigger a potential selection

	 * of a shared state for the domain, assumes the domain states are all
@@ -312,6 +320,7 @@ static void psci_cpu_deinit_idle(int cpu) 
	struct psci_cpuidle_data *data = per_cpu_ptr(&psci_cpuidle_data, cpu);



	dt_idle_detach_cpu(data->dev);

	psci_cpuidle_use_syscore = false;

	psci_cpuidle_use_cpuhp = false;

}
@@ -408,6 +417,7 @@ static int psci_cpuidle_probe(struct platform_device *pdev) 
			goto out_fail;

	}



	psci_idle_init_syscore();

	psci_idle_init_cpuhp();

	return 0;