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cpuidle: PSCI: Improve support for suspend-to-RAM for PSCI OSI mode

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[ Upstream commit 171b66e2e2e9d80b93c8cff799e6175074b22297 ]

When PSCI OSI mode is supported the syscore flag is set for the CPU devices
that becomes attached to their PM domains (genpds). In the suspend-to-idle
case, we call dev_pm_genpd_suspend|resume() to allow genpd to properly
manage the power-off/on operations (pick an idlestate and manage the on/off
notifications).

For suspend-to-ram, dev_pm_genpd_suspend|resume() is currently not being
called, which causes a problem that the genpd on/off notifiers do not get
sent as expected. This prevents the platform-specific operations from being
executed, typically needed just before/after the boot CPU is being turned
off/on.

To deal with this problem, let's register a syscore ops for cpuidle-psci
when PSCI OSI mode is being used and call dev_pm_genpd_suspend|resume()
from them. In this way, genpd regains control of the PM domain topology and
then sends the on/off notifications when it's appropriate.

Reported-by: Maulik Shah <quic_mkshah@quicinc.com>
Suggested-by: Maulik Shah <quic_mkshah@quicinc.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Maulik Shah <quic_mkshah@quicinc.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Ulf Hansson 2022-04-01 16:11:24 +02:00 committed by Greg Kroah-Hartman
parent ae373d66c4
commit 2bcec28ac0
1 changed files with 46 additions and 0 deletions
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46
drivers/cpuidle/cpuidle-psci.c
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@ -23,6 +23,7 @@
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/syscore_ops.h>
#include <asm/cpuidle.h>
@ -131,6 +132,49 @@ static int psci_idle_cpuhp_down(unsigned int cpu)
return 0;
}
static void psci_idle_syscore_switch(bool suspend)
{
bool cleared = false;
struct device *dev;
int cpu;
for_each_possible_cpu(cpu) {
dev = per_cpu_ptr(&psci_cpuidle_data, cpu)->dev;
if (dev && suspend) {
dev_pm_genpd_suspend(dev);
} else if (dev) {
dev_pm_genpd_resume(dev);
/* Account for userspace having offlined a CPU. */
if (pm_runtime_status_suspended(dev))
pm_runtime_set_active(dev);
/* Clear domain state to re-start fresh. */
if (!cleared) {
psci_set_domain_state(0);
cleared = true;
}
}
}
}
static int psci_idle_syscore_suspend(void)
{
psci_idle_syscore_switch(true);
return 0;
}
static void psci_idle_syscore_resume(void)
{
psci_idle_syscore_switch(false);
}
static struct syscore_ops psci_idle_syscore_ops = {
.suspend = psci_idle_syscore_suspend,
.resume = psci_idle_syscore_resume,
};
static void psci_idle_init_cpuhp(void)
{
int err;
@ -138,6 +182,8 @@ 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,