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>
diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
index fb56b61..4f97db3 100644
--- a/arch/arm64/kernel/psci.c
+++ b/arch/arm64/kernel/psci.c
@@ -256,11 +256,41 @@
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