arch/arm64/kernel/psci.c - linux - Git at Google

 /*
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * Copyright (C) 2013 ARM Limited
  *
  * Author: Will Deacon <will.deacon@arm.com>
  */

 #define pr_fmt(fmt) "psci: " fmt

 #include <linux/init.h>
 #include <linux/of.h>
 #include <linux/smp.h>

 #include <asm/compiler.h>
 #include <asm/cpu_ops.h>
 #include <asm/errno.h>
 #include <asm/psci.h>
 #include <asm/smp_plat.h>

 #define PSCI_POWER_STATE_TYPE_STANDBY		0
 #define PSCI_POWER_STATE_TYPE_POWER_DOWN	1

 struct psci_power_state {
 	u16	id;
 	u8	type;
 	u8	affinity_level;
 };

 struct psci_operations {
 	int (*cpu_suspend)(struct psci_power_state state,
 			   unsigned long entry_point);
 	int (*cpu_off)(struct psci_power_state state);
 	int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
 	int (*migrate)(unsigned long cpuid);
 };

 static struct psci_operations psci_ops;

 static int (*invoke_psci_fn)(u64, u64, u64, u64);

 enum psci_function {
 	PSCI_FN_CPU_SUSPEND,
 	PSCI_FN_CPU_ON,
 	PSCI_FN_CPU_OFF,
 	PSCI_FN_MIGRATE,
 	PSCI_FN_MAX,
 };

 static u32 psci_function_id[PSCI_FN_MAX];

 #define PSCI_RET_SUCCESS		0
 #define PSCI_RET_EOPNOTSUPP		-1
 #define PSCI_RET_EINVAL			-2
 #define PSCI_RET_EPERM			-3

 static int psci_to_linux_errno(int errno)
 {
 	switch (errno) {
 	case PSCI_RET_SUCCESS:
 		return 0;
 	case PSCI_RET_EOPNOTSUPP:
 		return -EOPNOTSUPP;
 	case PSCI_RET_EINVAL:
 		return -EINVAL;
 	case PSCI_RET_EPERM:
 		return -EPERM;
 	};

 	return -EINVAL;
 }

 #define PSCI_POWER_STATE_ID_MASK	0xffff
 #define PSCI_POWER_STATE_ID_SHIFT	0
 #define PSCI_POWER_STATE_TYPE_MASK	0x1
 #define PSCI_POWER_STATE_TYPE_SHIFT	16
 #define PSCI_POWER_STATE_AFFL_MASK	0x3
 #define PSCI_POWER_STATE_AFFL_SHIFT	24

 static u32 psci_power_state_pack(struct psci_power_state state)
 {
 	return	((state.id & PSCI_POWER_STATE_ID_MASK)
 			<< PSCI_POWER_STATE_ID_SHIFT)	|
 		((state.type & PSCI_POWER_STATE_TYPE_MASK)
 			<< PSCI_POWER_STATE_TYPE_SHIFT)	|
 		((state.affinity_level & PSCI_POWER_STATE_AFFL_MASK)
 			<< PSCI_POWER_STATE_AFFL_SHIFT);
 }

 /*
  * The following two functions are invoked via the invoke_psci_fn pointer
  * and will not be inlined, allowing us to piggyback on the AAPCS.
  */
 static noinline int __invoke_psci_fn_hvc(u64 function_id, u64 arg0, u64 arg1,
 					 u64 arg2)
 {
 	asm volatile(
 			__asmeq("%0", "x0")
 			__asmeq("%1", "x1")
 			__asmeq("%2", "x2")
 			__asmeq("%3", "x3")
 			"hvc	#0\n"
 		: "+r" (function_id)
 		: "r" (arg0), "r" (arg1), "r" (arg2));

 	return function_id;
 }

 static noinline int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 arg1,
 					 u64 arg2)
 {
 	asm volatile(
 			__asmeq("%0", "x0")
 			__asmeq("%1", "x1")
 			__asmeq("%2", "x2")
 			__asmeq("%3", "x3")
 			"smc	#0\n"
 		: "+r" (function_id)
 		: "r" (arg0), "r" (arg1), "r" (arg2));

 	return function_id;
 }

 static int psci_cpu_suspend(struct psci_power_state state,
 			    unsigned long entry_point)
 {
 	int err;
 	u32 fn, power_state;

 	fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
 	power_state = psci_power_state_pack(state);
 	err = invoke_psci_fn(fn, power_state, entry_point, 0);
 	return psci_to_linux_errno(err);
 }

 static int psci_cpu_off(struct psci_power_state state)
 {
 	int err;
 	u32 fn, power_state;

 	fn = psci_function_id[PSCI_FN_CPU_OFF];
 	power_state = psci_power_state_pack(state);
 	err = invoke_psci_fn(fn, power_state, 0, 0);
 	return psci_to_linux_errno(err);
 }

 static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
 {
 	int err;
 	u32 fn;

 	fn = psci_function_id[PSCI_FN_CPU_ON];
 	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
 	return psci_to_linux_errno(err);
 }

 static int psci_migrate(unsigned long cpuid)
 {
 	int err;
 	u32 fn;

 	fn = psci_function_id[PSCI_FN_MIGRATE];
 	err = invoke_psci_fn(fn, cpuid, 0, 0);
 	return psci_to_linux_errno(err);
 }

 static const struct of_device_id psci_of_match[] __initconst = {
 	{ .compatible = "arm,psci",	},
 	{},
 };

 void __init psci_init(void)
 {
 	struct device_node *np;
 	const char *method;
 	u32 id;

 	np = of_find_matching_node(NULL, psci_of_match);
 	if (!np)
 		return;

 	pr_info("probing function IDs from device-tree\n");

 	if (of_property_read_string(np, "method", &method)) {
 		pr_warning("missing \"method\" property\n");
 		goto out_put_node;
 	}

 	if (!strcmp("hvc", method)) {
 		invoke_psci_fn = __invoke_psci_fn_hvc;
 	} else if (!strcmp("smc", method)) {
 		invoke_psci_fn = __invoke_psci_fn_smc;
 	} else {
 		pr_warning("invalid \"method\" property: %s\n", method);
 		goto out_put_node;
 	}

 	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
 		psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
 		psci_ops.cpu_suspend = psci_cpu_suspend;
 	}

 	if (!of_property_read_u32(np, "cpu_off", &id)) {
 		psci_function_id[PSCI_FN_CPU_OFF] = id;
 		psci_ops.cpu_off = psci_cpu_off;
 	}

 	if (!of_property_read_u32(np, "cpu_on", &id)) {
 		psci_function_id[PSCI_FN_CPU_ON] = id;
 		psci_ops.cpu_on = psci_cpu_on;
 	}

 	if (!of_property_read_u32(np, "migrate", &id)) {
 		psci_function_id[PSCI_FN_MIGRATE] = id;
 		psci_ops.migrate = psci_migrate;
 	}

 out_put_node:
 	of_node_put(np);
 	return;
 }

 #ifdef CONFIG_SMP

 static int __init cpu_psci_cpu_init(struct device_node *dn, unsigned int cpu)
 {
 	return 0;
 }

 static int __init cpu_psci_cpu_prepare(unsigned int cpu)
 {
 	if (!psci_ops.cpu_on) {
 		pr_err("no cpu_on method, not booting CPU%d\n", cpu);
 		return -ENODEV;
 	}

 	return 0;
 }

 static int cpu_psci_cpu_boot(unsigned int cpu)
 {
 	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;
 }

 #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("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
	/*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* Copyright (C) 2013 ARM Limited
	*
	* Author: Will Deacon <will.deacon@arm.com>
	*/

	#define pr_fmt(fmt) "psci: " fmt

	#include <linux/init.h>
	#include <linux/of.h>
	#include <linux/smp.h>

	#include <asm/compiler.h>
	#include <asm/cpu_ops.h>
	#include <asm/errno.h>
	#include <asm/psci.h>
	#include <asm/smp_plat.h>

	#define PSCI_POWER_STATE_TYPE_STANDBY 0
	#define PSCI_POWER_STATE_TYPE_POWER_DOWN 1

	struct psci_power_state {
	u16 id;
	u8 type;
	u8 affinity_level;
	};

	struct psci_operations {
	int (*cpu_suspend)(struct psci_power_state state,
	unsigned long entry_point);
	int (*cpu_off)(struct psci_power_state state);
	int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
	int (*migrate)(unsigned long cpuid);
	};

	static struct psci_operations psci_ops;

	static int (*invoke_psci_fn)(u64, u64, u64, u64);

	enum psci_function {
	PSCI_FN_CPU_SUSPEND,
	PSCI_FN_CPU_ON,
	PSCI_FN_CPU_OFF,
	PSCI_FN_MIGRATE,
	PSCI_FN_MAX,
	};

	static u32 psci_function_id[PSCI_FN_MAX];

	#define PSCI_RET_SUCCESS 0
	#define PSCI_RET_EOPNOTSUPP -1
	#define PSCI_RET_EINVAL -2
	#define PSCI_RET_EPERM -3

	static int psci_to_linux_errno(int errno)
	{
	switch (errno) {
	case PSCI_RET_SUCCESS:
	return 0;
	case PSCI_RET_EOPNOTSUPP:
	return -EOPNOTSUPP;
	case PSCI_RET_EINVAL:
	return -EINVAL;
	case PSCI_RET_EPERM:
	return -EPERM;
	};

	return -EINVAL;
	}

	#define PSCI_POWER_STATE_ID_MASK 0xffff
	#define PSCI_POWER_STATE_ID_SHIFT 0
	#define PSCI_POWER_STATE_TYPE_MASK 0x1
	#define PSCI_POWER_STATE_TYPE_SHIFT 16
	#define PSCI_POWER_STATE_AFFL_MASK 0x3
	#define PSCI_POWER_STATE_AFFL_SHIFT 24

	static u32 psci_power_state_pack(struct psci_power_state state)
	{
	return ((state.id & PSCI_POWER_STATE_ID_MASK)
	<< PSCI_POWER_STATE_ID_SHIFT) \|
	((state.type & PSCI_POWER_STATE_TYPE_MASK)
	<< PSCI_POWER_STATE_TYPE_SHIFT) \|
	((state.affinity_level & PSCI_POWER_STATE_AFFL_MASK)
	<< PSCI_POWER_STATE_AFFL_SHIFT);
	}

	/*
	* The following two functions are invoked via the invoke_psci_fn pointer
	* and will not be inlined, allowing us to piggyback on the AAPCS.
	*/
	static noinline int __invoke_psci_fn_hvc(u64 function_id, u64 arg0, u64 arg1,
	u64 arg2)
	{
	asm volatile(
	__asmeq("%0", "x0")
	__asmeq("%1", "x1")
	__asmeq("%2", "x2")
	__asmeq("%3", "x3")
	"hvc #0\n"
	: "+r" (function_id)
	: "r" (arg0), "r" (arg1), "r" (arg2));

	return function_id;
	}

	static noinline int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 arg1,
	u64 arg2)
	{
	asm volatile(
	__asmeq("%0", "x0")
	__asmeq("%1", "x1")
	__asmeq("%2", "x2")
	__asmeq("%3", "x3")
	"smc #0\n"
	: "+r" (function_id)
	: "r" (arg0), "r" (arg1), "r" (arg2));

	return function_id;
	}

	static int psci_cpu_suspend(struct psci_power_state state,
	unsigned long entry_point)
	{
	int err;
	u32 fn, power_state;

	fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
	power_state = psci_power_state_pack(state);
	err = invoke_psci_fn(fn, power_state, entry_point, 0);
	return psci_to_linux_errno(err);
	}

	static int psci_cpu_off(struct psci_power_state state)
	{
	int err;
	u32 fn, power_state;

	fn = psci_function_id[PSCI_FN_CPU_OFF];
	power_state = psci_power_state_pack(state);
	err = invoke_psci_fn(fn, power_state, 0, 0);
	return psci_to_linux_errno(err);
	}

	static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
	{
	int err;
	u32 fn;

	fn = psci_function_id[PSCI_FN_CPU_ON];
	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
	return psci_to_linux_errno(err);
	}

	static int psci_migrate(unsigned long cpuid)
	{
	int err;
	u32 fn;

	fn = psci_function_id[PSCI_FN_MIGRATE];
	err = invoke_psci_fn(fn, cpuid, 0, 0);
	return psci_to_linux_errno(err);
	}

	static const struct of_device_id psci_of_match[] __initconst = {
	{ .compatible = "arm,psci", },
	{},
	};

	void __init psci_init(void)
	{
	struct device_node *np;
	const char *method;
	u32 id;

	np = of_find_matching_node(NULL, psci_of_match);
	if (!np)
	return;

	pr_info("probing function IDs from device-tree\n");

	if (of_property_read_string(np, "method", &method)) {
	pr_warning("missing \"method\" property\n");
	goto out_put_node;
	}

	if (!strcmp("hvc", method)) {
	invoke_psci_fn = __invoke_psci_fn_hvc;
	} else if (!strcmp("smc", method)) {
	invoke_psci_fn = __invoke_psci_fn_smc;
	} else {
	pr_warning("invalid \"method\" property: %s\n", method);
	goto out_put_node;
	}

	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
	psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
	psci_ops.cpu_suspend = psci_cpu_suspend;
	}

	if (!of_property_read_u32(np, "cpu_off", &id)) {
	psci_function_id[PSCI_FN_CPU_OFF] = id;
	psci_ops.cpu_off = psci_cpu_off;
	}

	if (!of_property_read_u32(np, "cpu_on", &id)) {
	psci_function_id[PSCI_FN_CPU_ON] = id;
	psci_ops.cpu_on = psci_cpu_on;
	}

	if (!of_property_read_u32(np, "migrate", &id)) {
	psci_function_id[PSCI_FN_MIGRATE] = id;
	psci_ops.migrate = psci_migrate;
	}

	out_put_node:
	of_node_put(np);
	return;
	}

	#ifdef CONFIG_SMP

	static int __init cpu_psci_cpu_init(struct device_node *dn, unsigned int cpu)
	{
	return 0;
	}

	static int __init cpu_psci_cpu_prepare(unsigned int cpu)
	{
	if (!psci_ops.cpu_on) {
	pr_err("no cpu_on method, not booting CPU%d\n", cpu);
	return -ENODEV;
	}

	return 0;
	}

	static int cpu_psci_cpu_boot(unsigned int cpu)
	{
	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;
	}

	#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("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