drivers/firmware/psci/psci.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *
  * Copyright (C) 2015 ARM Limited
  */

 #define pr_fmt(fmt) "psci: " fmt

 #include <linux/acpi.h>
 #include <linux/arm-smccc.h>
 #include <linux/cpuidle.h>
 #include <linux/errno.h>
 #include <linux/linkage.h>
 #include <linux/of.h>
 #include <linux/pm.h>
 #include <linux/printk.h>
 #include <linux/psci.h>
 #include <linux/reboot.h>
 #include <linux/slab.h>
 #include <linux/suspend.h>

 #include <uapi/linux/psci.h>

 #include <asm/cpuidle.h>
 #include <asm/cputype.h>
 #include <asm/system_misc.h>
 #include <asm/smp_plat.h>
 #include <asm/suspend.h>

 /*
  * While a 64-bit OS can make calls with SMC32 calling conventions, for some
  * calls it is necessary to use SMC64 to pass or return 64-bit values.
  * For such calls PSCI_FN_NATIVE(version, name) will choose the appropriate
  * (native-width) function ID.
  */
 #ifdef CONFIG_64BIT
 #define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN64_##name
 #else
 #define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN_##name
 #endif

 /*
  * The CPU any Trusted OS is resident on. The trusted OS may reject CPU_OFF
  * calls to its resident CPU, so we must avoid issuing those. We never migrate
  * a Trusted OS even if it claims to be capable of migration -- doing so will
  * require cooperation with a Trusted OS driver.
  */
 static int resident_cpu = -1;

 bool psci_tos_resident_on(int cpu)
 {
 	return cpu == resident_cpu;
 }

 struct psci_operations psci_ops = {
 	.conduit = PSCI_CONDUIT_NONE,
 	.smccc_version = SMCCC_VERSION_1_0,
 };

 typedef unsigned long (psci_fn)(unsigned long, unsigned long,
 				unsigned long, unsigned long);
 static psci_fn *invoke_psci_fn;

 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_0_2_POWER_STATE_MASK		\
 				(PSCI_0_2_POWER_STATE_ID_MASK | \
 				PSCI_0_2_POWER_STATE_TYPE_MASK | \
 				PSCI_0_2_POWER_STATE_AFFL_MASK)

 #define PSCI_1_0_EXT_POWER_STATE_MASK		\
 				(PSCI_1_0_EXT_POWER_STATE_ID_MASK | \
 				PSCI_1_0_EXT_POWER_STATE_TYPE_MASK)

 static u32 psci_cpu_suspend_feature;
 static bool psci_system_reset2_supported;

 static inline bool psci_has_ext_power_state(void)
 {
 	return psci_cpu_suspend_feature &
 				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
 }

 static inline bool psci_has_osi_support(void)
 {
 	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
 }

 static inline bool psci_power_state_loses_context(u32 state)
 {
 	const u32 mask = psci_has_ext_power_state() ?
 					PSCI_1_0_EXT_POWER_STATE_TYPE_MASK :
 					PSCI_0_2_POWER_STATE_TYPE_MASK;

 	return state & mask;
 }

 bool psci_power_state_is_valid(u32 state)
 {
 	const u32 valid_mask = psci_has_ext_power_state() ?
 			       PSCI_1_0_EXT_POWER_STATE_MASK :
 			       PSCI_0_2_POWER_STATE_MASK;

 	return !(state & ~valid_mask);
 }

 static unsigned long __invoke_psci_fn_hvc(unsigned long function_id,
 			unsigned long arg0, unsigned long arg1,
 			unsigned long arg2)
 {
 	struct arm_smccc_res res;

 	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
 	return res.a0;
 }

 static unsigned long __invoke_psci_fn_smc(unsigned long function_id,
 			unsigned long arg0, unsigned long arg1,
 			unsigned long arg2)
 {
 	struct arm_smccc_res res;

 	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
 	return res.a0;
 }

 static int psci_to_linux_errno(int errno)
 {
 	switch (errno) {
 	case PSCI_RET_SUCCESS:
 		return 0;
 	case PSCI_RET_NOT_SUPPORTED:
 		return -EOPNOTSUPP;
 	case PSCI_RET_INVALID_PARAMS:
 	case PSCI_RET_INVALID_ADDRESS:
 		return -EINVAL;
 	case PSCI_RET_DENIED:
 		return -EPERM;
 	};

 	return -EINVAL;
 }

 static u32 psci_get_version(void)
 {
 	return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
 }

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

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

 static int psci_cpu_off(u32 state)
 {
 	int err;
 	u32 fn;

 	fn = psci_function_id[PSCI_FN_CPU_OFF];
 	err = invoke_psci_fn(fn, 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 int psci_affinity_info(unsigned long target_affinity,
 		unsigned long lowest_affinity_level)
 {
 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, AFFINITY_INFO),
 			      target_affinity, lowest_affinity_level, 0);
 }

 static int psci_migrate_info_type(void)
 {
 	return invoke_psci_fn(PSCI_0_2_FN_MIGRATE_INFO_TYPE, 0, 0, 0);
 }

 static unsigned long psci_migrate_info_up_cpu(void)
 {
 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
 			      0, 0, 0);
 }

 static void set_conduit(enum psci_conduit conduit)
 {
 	switch (conduit) {
 	case PSCI_CONDUIT_HVC:
 		invoke_psci_fn = __invoke_psci_fn_hvc;
 		break;
 	case PSCI_CONDUIT_SMC:
 		invoke_psci_fn = __invoke_psci_fn_smc;
 		break;
 	default:
 		WARN(1, "Unexpected PSCI conduit %d\n", conduit);
 	}

 	psci_ops.conduit = conduit;
 }

 static int get_set_conduit_method(struct device_node *np)
 {
 	const char *method;

 	pr_info("probing for conduit method from DT.\n");

 	if (of_property_read_string(np, "method", &method)) {
 		pr_warn("missing \"method\" property\n");
 		return -ENXIO;
 	}

 	if (!strcmp("hvc", method)) {
 		set_conduit(PSCI_CONDUIT_HVC);
 	} else if (!strcmp("smc", method)) {
 		set_conduit(PSCI_CONDUIT_SMC);
 	} else {
 		pr_warn("invalid \"method\" property: %s\n", method);
 		return -EINVAL;
 	}
 	return 0;
 }

 static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
 {
 	if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
 	    psci_system_reset2_supported) {
 		/*
 		 * reset_type[31] = 0 (architectural)
 		 * reset_type[30:0] = 0 (SYSTEM_WARM_RESET)
 		 * cookie = 0 (ignored by the implementation)
 		 */
 		invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0);
 	} else {
 		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
 	}
 }

 static void psci_sys_poweroff(void)
 {
 	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
 }

 static int __init psci_features(u32 psci_func_id)
 {
 	return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
 			      psci_func_id, 0, 0);
 }

 #ifdef CONFIG_CPU_IDLE
 static int psci_suspend_finisher(unsigned long state)
 {
 	u32 power_state = state;

 	return psci_ops.cpu_suspend(power_state, __pa_symbol(cpu_resume));
 }

 int psci_cpu_suspend_enter(u32 state)
 {
 	int ret;

 	if (!psci_power_state_loses_context(state))
 		ret = psci_ops.cpu_suspend(state, 0);
 	else
 		ret = cpu_suspend(state, psci_suspend_finisher);

 	return ret;
 }
 #endif

 static int psci_system_suspend(unsigned long unused)
 {
 	return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
 			      __pa_symbol(cpu_resume), 0, 0);
 }

 static int psci_system_suspend_enter(suspend_state_t state)
 {
 	return cpu_suspend(0, psci_system_suspend);
 }

 static const struct platform_suspend_ops psci_suspend_ops = {
 	.valid          = suspend_valid_only_mem,
 	.enter          = psci_system_suspend_enter,
 };

 static void __init psci_init_system_reset2(void)
 {
 	int ret;

 	ret = psci_features(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2));

 	if (ret != PSCI_RET_NOT_SUPPORTED)
 		psci_system_reset2_supported = true;
 }

 static void __init psci_init_system_suspend(void)
 {
 	int ret;

 	if (!IS_ENABLED(CONFIG_SUSPEND))
 		return;

 	ret = psci_features(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND));

 	if (ret != PSCI_RET_NOT_SUPPORTED)
 		suspend_set_ops(&psci_suspend_ops);
 }

 static void __init psci_init_cpu_suspend(void)
 {
 	int feature = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);

 	if (feature != PSCI_RET_NOT_SUPPORTED)
 		psci_cpu_suspend_feature = feature;
 }

 /*
  * Detect the presence of a resident Trusted OS which may cause CPU_OFF to
  * return DENIED (which would be fatal).
  */
 static void __init psci_init_migrate(void)
 {
 	unsigned long cpuid;
 	int type, cpu = -1;

 	type = psci_ops.migrate_info_type();

 	if (type == PSCI_0_2_TOS_MP) {
 		pr_info("Trusted OS migration not required\n");
 		return;
 	}

 	if (type == PSCI_RET_NOT_SUPPORTED) {
 		pr_info("MIGRATE_INFO_TYPE not supported.\n");
 		return;
 	}

 	if (type != PSCI_0_2_TOS_UP_MIGRATE &&
 	    type != PSCI_0_2_TOS_UP_NO_MIGRATE) {
 		pr_err("MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
 		return;
 	}

 	cpuid = psci_migrate_info_up_cpu();
 	if (cpuid & ~MPIDR_HWID_BITMASK) {
 		pr_warn("MIGRATE_INFO_UP_CPU reported invalid physical ID (0x%lx)\n",
 			cpuid);
 		return;
 	}

 	cpu = get_logical_index(cpuid);
 	resident_cpu = cpu >= 0 ? cpu : -1;

 	pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid);
 }

 static void __init psci_init_smccc(void)
 {
 	u32 ver = ARM_SMCCC_VERSION_1_0;
 	int feature;

 	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);

 	if (feature != PSCI_RET_NOT_SUPPORTED) {
 		u32 ret;
 		ret = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
 		if (ret == ARM_SMCCC_VERSION_1_1) {
 			psci_ops.smccc_version = SMCCC_VERSION_1_1;
 			ver = ret;
 		}
 	}

 	/*
 	 * Conveniently, the SMCCC and PSCI versions are encoded the
 	 * same way. No, this isn't accidental.
 	 */
 	pr_info("SMC Calling Convention v%d.%d\n",
 		PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver));

 }

 static void __init psci_0_2_set_functions(void)
 {
 	pr_info("Using standard PSCI v0.2 function IDs\n");
 	psci_ops.get_version = psci_get_version;

 	psci_function_id[PSCI_FN_CPU_SUSPEND] =
 					PSCI_FN_NATIVE(0_2, CPU_SUSPEND);
 	psci_ops.cpu_suspend = psci_cpu_suspend;

 	psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
 	psci_ops.cpu_off = psci_cpu_off;

 	psci_function_id[PSCI_FN_CPU_ON] = PSCI_FN_NATIVE(0_2, CPU_ON);
 	psci_ops.cpu_on = psci_cpu_on;

 	psci_function_id[PSCI_FN_MIGRATE] = PSCI_FN_NATIVE(0_2, MIGRATE);
 	psci_ops.migrate = psci_migrate;

 	psci_ops.affinity_info = psci_affinity_info;

 	psci_ops.migrate_info_type = psci_migrate_info_type;

 	arm_pm_restart = psci_sys_reset;

 	pm_power_off = psci_sys_poweroff;
 }

 /*
  * Probe function for PSCI firmware versions >= 0.2
  */
 static int __init psci_probe(void)
 {
 	u32 ver = psci_get_version();

 	pr_info("PSCIv%d.%d detected in firmware.\n",
 			PSCI_VERSION_MAJOR(ver),
 			PSCI_VERSION_MINOR(ver));

 	if (PSCI_VERSION_MAJOR(ver) == 0 && PSCI_VERSION_MINOR(ver) < 2) {
 		pr_err("Conflicting PSCI version detected.\n");
 		return -EINVAL;
 	}

 	psci_0_2_set_functions();

 	psci_init_migrate();

 	if (PSCI_VERSION_MAJOR(ver) >= 1) {
 		psci_init_smccc();
 		psci_init_cpu_suspend();
 		psci_init_system_suspend();
 		psci_init_system_reset2();
 	}

 	return 0;
 }

 typedef int (*psci_initcall_t)(const struct device_node *);

 /*
  * PSCI init function for PSCI versions >=0.2
  *
  * Probe based on PSCI PSCI_VERSION function
  */
 static int __init psci_0_2_init(struct device_node *np)
 {
 	int err;

 	err = get_set_conduit_method(np);
 	if (err)
 		return err;

 	/*
 	 * Starting with v0.2, the PSCI specification introduced a call
 	 * (PSCI_VERSION) that allows probing the firmware version, so
 	 * that PSCI function IDs and version specific initialization
 	 * can be carried out according to the specific version reported
 	 * by firmware
 	 */
 	return psci_probe();
 }

 /*
  * PSCI < v0.2 get PSCI Function IDs via DT.
  */
 static int __init psci_0_1_init(struct device_node *np)
 {
 	u32 id;
 	int err;

 	err = get_set_conduit_method(np);
 	if (err)
 		return err;

 	pr_info("Using PSCI v0.1 Function IDs from DT\n");

 	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;
 	}

 	return 0;
 }

 static int __init psci_1_0_init(struct device_node *np)
 {
 	int err;

 	err = psci_0_2_init(np);
 	if (err)
 		return err;

 	if (psci_has_osi_support())
 		pr_info("OSI mode supported.\n");

 	return 0;
 }

 static const struct of_device_id psci_of_match[] __initconst = {
 	{ .compatible = "arm,psci",	.data = psci_0_1_init},
 	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
 	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
 	{},
 };

 int __init psci_dt_init(void)
 {
 	struct device_node *np;
 	const struct of_device_id *matched_np;
 	psci_initcall_t init_fn;
 	int ret;

 	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);

 	if (!np || !of_device_is_available(np))
 		return -ENODEV;

 	init_fn = (psci_initcall_t)matched_np->data;
 	ret = init_fn(np);

 	of_node_put(np);
 	return ret;
 }

 #ifdef CONFIG_ACPI
 /*
  * We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's
  * explicitly clarified in SBBR
  */
 int __init psci_acpi_init(void)
 {
 	if (!acpi_psci_present()) {
 		pr_info("is not implemented in ACPI.\n");
 		return -EOPNOTSUPP;
 	}

 	pr_info("probing for conduit method from ACPI.\n");

 	if (acpi_psci_use_hvc())
 		set_conduit(PSCI_CONDUIT_HVC);
 	else
 		set_conduit(PSCI_CONDUIT_SMC);

 	return psci_probe();
 }
 #endif
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	*
	* Copyright (C) 2015 ARM Limited
	*/

	#define pr_fmt(fmt) "psci: " fmt

	#include <linux/acpi.h>
	#include <linux/arm-smccc.h>
	#include <linux/cpuidle.h>
	#include <linux/errno.h>
	#include <linux/linkage.h>
	#include <linux/of.h>
	#include <linux/pm.h>
	#include <linux/printk.h>
	#include <linux/psci.h>
	#include <linux/reboot.h>
	#include <linux/slab.h>
	#include <linux/suspend.h>

	#include <uapi/linux/psci.h>

	#include <asm/cpuidle.h>
	#include <asm/cputype.h>
	#include <asm/system_misc.h>
	#include <asm/smp_plat.h>
	#include <asm/suspend.h>

	/*
	* While a 64-bit OS can make calls with SMC32 calling conventions, for some
	* calls it is necessary to use SMC64 to pass or return 64-bit values.
	* For such calls PSCI_FN_NATIVE(version, name) will choose the appropriate
	* (native-width) function ID.
	*/
	#ifdef CONFIG_64BIT
	#define PSCI_FN_NATIVE(version, name) PSCI_##version##_FN64_##name
	#else
	#define PSCI_FN_NATIVE(version, name) PSCI_##version##_FN_##name
	#endif

	/*
	* The CPU any Trusted OS is resident on. The trusted OS may reject CPU_OFF
	* calls to its resident CPU, so we must avoid issuing those. We never migrate
	* a Trusted OS even if it claims to be capable of migration -- doing so will
	* require cooperation with a Trusted OS driver.
	*/
	static int resident_cpu = -1;

	bool psci_tos_resident_on(int cpu)
	{
	return cpu == resident_cpu;
	}

	struct psci_operations psci_ops = {
	.conduit = PSCI_CONDUIT_NONE,
	.smccc_version = SMCCC_VERSION_1_0,
	};

	typedef unsigned long (psci_fn)(unsigned long, unsigned long,
	unsigned long, unsigned long);
	static psci_fn *invoke_psci_fn;

	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_0_2_POWER_STATE_MASK \
	(PSCI_0_2_POWER_STATE_ID_MASK \| \
	PSCI_0_2_POWER_STATE_TYPE_MASK \| \
	PSCI_0_2_POWER_STATE_AFFL_MASK)

	#define PSCI_1_0_EXT_POWER_STATE_MASK \
	(PSCI_1_0_EXT_POWER_STATE_ID_MASK \| \
	PSCI_1_0_EXT_POWER_STATE_TYPE_MASK)

	static u32 psci_cpu_suspend_feature;
	static bool psci_system_reset2_supported;

	static inline bool psci_has_ext_power_state(void)
	{
	return psci_cpu_suspend_feature &
	PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
	}

	static inline bool psci_has_osi_support(void)
	{
	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
	}

	static inline bool psci_power_state_loses_context(u32 state)
	{
	const u32 mask = psci_has_ext_power_state() ?
	PSCI_1_0_EXT_POWER_STATE_TYPE_MASK :
	PSCI_0_2_POWER_STATE_TYPE_MASK;

	return state & mask;
	}

	bool psci_power_state_is_valid(u32 state)
	{
	const u32 valid_mask = psci_has_ext_power_state() ?
	PSCI_1_0_EXT_POWER_STATE_MASK :
	PSCI_0_2_POWER_STATE_MASK;

	return !(state & ~valid_mask);
	}

	static unsigned long __invoke_psci_fn_hvc(unsigned long function_id,
	unsigned long arg0, unsigned long arg1,
	unsigned long arg2)
	{
	struct arm_smccc_res res;

	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
	return res.a0;
	}

	static unsigned long __invoke_psci_fn_smc(unsigned long function_id,
	unsigned long arg0, unsigned long arg1,
	unsigned long arg2)
	{
	struct arm_smccc_res res;

	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
	return res.a0;
	}

	static int psci_to_linux_errno(int errno)
	{
	switch (errno) {
	case PSCI_RET_SUCCESS:
	return 0;
	case PSCI_RET_NOT_SUPPORTED:
	return -EOPNOTSUPP;
	case PSCI_RET_INVALID_PARAMS:
	case PSCI_RET_INVALID_ADDRESS:
	return -EINVAL;
	case PSCI_RET_DENIED:
	return -EPERM;
	};

	return -EINVAL;
	}

	static u32 psci_get_version(void)
	{
	return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
	}

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

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

	static int psci_cpu_off(u32 state)
	{
	int err;
	u32 fn;

	fn = psci_function_id[PSCI_FN_CPU_OFF];
	err = invoke_psci_fn(fn, 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 int psci_affinity_info(unsigned long target_affinity,
	unsigned long lowest_affinity_level)
	{
	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, AFFINITY_INFO),
	target_affinity, lowest_affinity_level, 0);
	}

	static int psci_migrate_info_type(void)
	{
	return invoke_psci_fn(PSCI_0_2_FN_MIGRATE_INFO_TYPE, 0, 0, 0);
	}

	static unsigned long psci_migrate_info_up_cpu(void)
	{
	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
	0, 0, 0);
	}

	static void set_conduit(enum psci_conduit conduit)
	{
	switch (conduit) {
	case PSCI_CONDUIT_HVC:
	invoke_psci_fn = __invoke_psci_fn_hvc;
	break;
	case PSCI_CONDUIT_SMC:
	invoke_psci_fn = __invoke_psci_fn_smc;
	break;
	default:
	WARN(1, "Unexpected PSCI conduit %d\n", conduit);
	}

	psci_ops.conduit = conduit;
	}

	static int get_set_conduit_method(struct device_node *np)
	{
	const char *method;

	pr_info("probing for conduit method from DT.\n");

	if (of_property_read_string(np, "method", &method)) {
	pr_warn("missing \"method\" property\n");
	return -ENXIO;
	}

	if (!strcmp("hvc", method)) {
	set_conduit(PSCI_CONDUIT_HVC);
	} else if (!strcmp("smc", method)) {
	set_conduit(PSCI_CONDUIT_SMC);
	} else {
	pr_warn("invalid \"method\" property: %s\n", method);
	return -EINVAL;
	}
	return 0;
	}

	static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
	{
	if ((reboot_mode == REBOOT_WARM \|\| reboot_mode == REBOOT_SOFT) &&
	psci_system_reset2_supported) {
	/*
	* reset_type[31] = 0 (architectural)
	* reset_type[30:0] = 0 (SYSTEM_WARM_RESET)
	* cookie = 0 (ignored by the implementation)
	*/
	invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0);
	} else {
	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
	}
	}

	static void psci_sys_poweroff(void)
	{
	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
	}

	static int __init psci_features(u32 psci_func_id)
	{
	return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
	psci_func_id, 0, 0);
	}

	#ifdef CONFIG_CPU_IDLE
	static int psci_suspend_finisher(unsigned long state)
	{
	u32 power_state = state;

	return psci_ops.cpu_suspend(power_state, __pa_symbol(cpu_resume));
	}

	int psci_cpu_suspend_enter(u32 state)
	{
	int ret;

	if (!psci_power_state_loses_context(state))
	ret = psci_ops.cpu_suspend(state, 0);
	else
	ret = cpu_suspend(state, psci_suspend_finisher);

	return ret;
	}
	#endif

	static int psci_system_suspend(unsigned long unused)
	{
	return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
	__pa_symbol(cpu_resume), 0, 0);
	}

	static int psci_system_suspend_enter(suspend_state_t state)
	{
	return cpu_suspend(0, psci_system_suspend);
	}

	static const struct platform_suspend_ops psci_suspend_ops = {
	.valid = suspend_valid_only_mem,
	.enter = psci_system_suspend_enter,
	};

	static void __init psci_init_system_reset2(void)
	{
	int ret;

	ret = psci_features(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2));

	if (ret != PSCI_RET_NOT_SUPPORTED)
	psci_system_reset2_supported = true;
	}

	static void __init psci_init_system_suspend(void)
	{
	int ret;

	if (!IS_ENABLED(CONFIG_SUSPEND))
	return;

	ret = psci_features(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND));

	if (ret != PSCI_RET_NOT_SUPPORTED)
	suspend_set_ops(&psci_suspend_ops);
	}

	static void __init psci_init_cpu_suspend(void)
	{
	int feature = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);

	if (feature != PSCI_RET_NOT_SUPPORTED)
	psci_cpu_suspend_feature = feature;
	}

	/*
	* Detect the presence of a resident Trusted OS which may cause CPU_OFF to
	* return DENIED (which would be fatal).
	*/
	static void __init psci_init_migrate(void)
	{
	unsigned long cpuid;
	int type, cpu = -1;

	type = psci_ops.migrate_info_type();

	if (type == PSCI_0_2_TOS_MP) {
	pr_info("Trusted OS migration not required\n");
	return;
	}

	if (type == PSCI_RET_NOT_SUPPORTED) {
	pr_info("MIGRATE_INFO_TYPE not supported.\n");
	return;
	}

	if (type != PSCI_0_2_TOS_UP_MIGRATE &&
	type != PSCI_0_2_TOS_UP_NO_MIGRATE) {
	pr_err("MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
	return;
	}

	cpuid = psci_migrate_info_up_cpu();
	if (cpuid & ~MPIDR_HWID_BITMASK) {
	pr_warn("MIGRATE_INFO_UP_CPU reported invalid physical ID (0x%lx)\n",
	cpuid);
	return;
	}

	cpu = get_logical_index(cpuid);
	resident_cpu = cpu >= 0 ? cpu : -1;

	pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid);
	}

	static void __init psci_init_smccc(void)
	{
	u32 ver = ARM_SMCCC_VERSION_1_0;
	int feature;

	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);

	if (feature != PSCI_RET_NOT_SUPPORTED) {
	u32 ret;
	ret = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
	if (ret == ARM_SMCCC_VERSION_1_1) {
	psci_ops.smccc_version = SMCCC_VERSION_1_1;
	ver = ret;
	}
	}

	/*
	* Conveniently, the SMCCC and PSCI versions are encoded the
	* same way. No, this isn't accidental.
	*/
	pr_info("SMC Calling Convention v%d.%d\n",
	PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver));

	}

	static void __init psci_0_2_set_functions(void)
	{
	pr_info("Using standard PSCI v0.2 function IDs\n");
	psci_ops.get_version = psci_get_version;

	psci_function_id[PSCI_FN_CPU_SUSPEND] =
	PSCI_FN_NATIVE(0_2, CPU_SUSPEND);
	psci_ops.cpu_suspend = psci_cpu_suspend;

	psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
	psci_ops.cpu_off = psci_cpu_off;

	psci_function_id[PSCI_FN_CPU_ON] = PSCI_FN_NATIVE(0_2, CPU_ON);
	psci_ops.cpu_on = psci_cpu_on;

	psci_function_id[PSCI_FN_MIGRATE] = PSCI_FN_NATIVE(0_2, MIGRATE);
	psci_ops.migrate = psci_migrate;

	psci_ops.affinity_info = psci_affinity_info;

	psci_ops.migrate_info_type = psci_migrate_info_type;

	arm_pm_restart = psci_sys_reset;

	pm_power_off = psci_sys_poweroff;
	}

	/*
	* Probe function for PSCI firmware versions >= 0.2
	*/
	static int __init psci_probe(void)
	{
	u32 ver = psci_get_version();

	pr_info("PSCIv%d.%d detected in firmware.\n",
	PSCI_VERSION_MAJOR(ver),
	PSCI_VERSION_MINOR(ver));

	if (PSCI_VERSION_MAJOR(ver) == 0 && PSCI_VERSION_MINOR(ver) < 2) {
	pr_err("Conflicting PSCI version detected.\n");
	return -EINVAL;
	}

	psci_0_2_set_functions();

	psci_init_migrate();

	if (PSCI_VERSION_MAJOR(ver) >= 1) {
	psci_init_smccc();
	psci_init_cpu_suspend();
	psci_init_system_suspend();
	psci_init_system_reset2();
	}

	return 0;
	}

	typedef int (psci_initcall_t)(const struct device_node );

	/*
	* PSCI init function for PSCI versions >=0.2
	*
	* Probe based on PSCI PSCI_VERSION function
	*/
	static int __init psci_0_2_init(struct device_node *np)
	{
	int err;

	err = get_set_conduit_method(np);
	if (err)
	return err;

	/*
	* Starting with v0.2, the PSCI specification introduced a call
	* (PSCI_VERSION) that allows probing the firmware version, so
	* that PSCI function IDs and version specific initialization
	* can be carried out according to the specific version reported
	* by firmware
	*/
	return psci_probe();
	}

	/*
	* PSCI < v0.2 get PSCI Function IDs via DT.
	*/
	static int __init psci_0_1_init(struct device_node *np)
	{
	u32 id;
	int err;

	err = get_set_conduit_method(np);
	if (err)
	return err;

	pr_info("Using PSCI v0.1 Function IDs from DT\n");

	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;
	}

	return 0;
	}

	static int __init psci_1_0_init(struct device_node *np)
	{
	int err;

	err = psci_0_2_init(np);
	if (err)
	return err;

	if (psci_has_osi_support())
	pr_info("OSI mode supported.\n");

	return 0;
	}

	static const struct of_device_id psci_of_match[] __initconst = {
	{ .compatible = "arm,psci", .data = psci_0_1_init},
	{ .compatible = "arm,psci-0.2", .data = psci_0_2_init},
	{ .compatible = "arm,psci-1.0", .data = psci_1_0_init},
	{},
	};

	int __init psci_dt_init(void)
	{
	struct device_node *np;
	const struct of_device_id *matched_np;
	psci_initcall_t init_fn;
	int ret;

	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);

	if (!np \|\| !of_device_is_available(np))
	return -ENODEV;

	init_fn = (psci_initcall_t)matched_np->data;
	ret = init_fn(np);

	of_node_put(np);
	return ret;
	}

	#ifdef CONFIG_ACPI
	/*
	* We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's
	* explicitly clarified in SBBR
	*/
	int __init psci_acpi_init(void)
	{
	if (!acpi_psci_present()) {
	pr_info("is not implemented in ACPI.\n");
	return -EOPNOTSUPP;
	}

	pr_info("probing for conduit method from ACPI.\n");

	if (acpi_psci_use_hvc())
	set_conduit(PSCI_CONDUIT_HVC);
	else
	set_conduit(PSCI_CONDUIT_SMC);

	return psci_probe();
	}
	#endif