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arm64: add PSCI CPU_OFF-based hotplug support 

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>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
hifive-unleashed-5.1
Mark Rutland 2013-10-24 20:30:19 +01:00 committed by Catalin Marinas
parent 9327e2c6bb
commit 831ccf79b4
1 changed files with 30 additions and 0 deletions
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30
arch/arm64/kernel/psci.c
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@ -256,11 +256,41 @@ static int cpu_psci_cpu_boot(unsigned int cpu)
return err;
}
#ifdef CONFIG_HOTPLUG_CPU
static int cpu_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 cpu_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 cpu_operations cpu_psci_ops = {
.name = "psci",
.cpu_init = cpu_psci_cpu_init,
.cpu_prepare = cpu_psci_cpu_prepare,
.cpu_boot = cpu_psci_cpu_boot,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_disable = cpu_psci_cpu_disable,
.cpu_die = cpu_psci_cpu_die,
#endif
};
#endif