[PATCHv3 5/5] arm64: add PSCI CPU_OFF-based hotplug support
From: mark.rutland@arm.com (Mark Rutland)
Date: 2013-08-14 16:20:28
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
This patch adds support for using PSCI CPU_OFF calls for CPU hotplug. With this code it is possible to hot unplug CPUs with "psci" as their boot-method, as long as there's an appropriate cpu_off function id specified in the psci node. Signed-off-by: Mark Rutland <mark.rutland@arm.com> --- arch/arm64/kernel/smp_psci.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)
diff --git a/arch/arm64/kernel/smp_psci.c b/arch/arm64/kernel/smp_psci.c
index 20499bc..e9e5890 100644
--- a/arch/arm64/kernel/smp_psci.c
+++ b/arch/arm64/kernel/smp_psci.c@@ -47,9 +47,39 @@ static int smp_psci_cpu_boot(unsigned int cpu) return err; } +#ifdef CONFIG_HOTPLUG_CPU +static int smp_psci_cpu_disable(unsigned int cpu) +{ + /* Fail early if we don't have CPU_OFF support */ + if (!psci_ops.cpu_off) + return -EOPNOTSUPP; + return 0; +} + +static void smp_psci_cpu_die(unsigned int cpu) +{ + int ret; + /* + * There are no known implementations of PSCI actually using the + * power state field, pass a sensible default for now. + */ + struct psci_power_state state = { + .type = PSCI_POWER_STATE_TYPE_POWER_DOWN, + }; + + ret = psci_ops.cpu_off(state); + + pr_crit("psci: unable to power off CPU%u (%d)\n", cpu, ret); +} +#endif + const struct smp_operations smp_psci_ops = { .name = "psci", .cpu_init = smp_psci_cpu_init, .cpu_prepare = smp_psci_cpu_prepare, .cpu_boot = smp_psci_cpu_boot, +#ifdef CONFIG_HOTPLUG_CPU + .cpu_disable = smp_psci_cpu_disable, + .cpu_die = smp_psci_cpu_die, +#endif };
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1.8.1.1