cpu_ops接口

驅動初始化完成后，cpu的cpu_ops就可以調用這些回調實現psci功能的調用。如下所示，當devicetree中cpu的enable-method設置為psci時，該cpu的cpu_ops將指向cpu_psci_ops。

cpu0: cpu@0 {
	...
	enable-method = "psci";
	…
}

其中cpu_psci_ops的定義如下：

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_can_disable = cpu_psci_cpu_can_disable,
	.cpu_disable	= cpu_psci_cpu_disable,
	.cpu_die	= cpu_psci_cpu_die,
	.cpu_kill	= cpu_psci_cpu_kill,
#endif
}

如啟動cpu的接口為cpu_psci_cpu_boot，它會通過以下流程最終調用psci驅動中的psci_ops函數：

static int cpu_psci_cpu_boot(unsigned int cpu)
{
	phys_addr_t pa_secondary_entry = __pa_symbol(function_nocfi(secondary_entry));
	int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry);
	if (err)
		pr_err("failed to boot CPU%d (%d)n", cpu, err);

	return err;
}