Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 791 insertions, 0 deletions

diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
new file mode 100644
index 0000000000..d9629ff878
--- /dev/null
+++ b/drivers/firmware/psci/psci.c
@@ -0,0 +1,791 @@
+// 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/debugfs.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/hypervisor.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;
+struct psci_operations psci_ops;
+static enum arm_smccc_conduit psci_conduit = SMCCC_CONDUIT_NONE;
+
+bool psci_tos_resident_on(int cpu)
+{
+	return cpu == resident_cpu;
+}
+
+typedef unsigned long (psci_fn)(unsigned long, unsigned long,
+				unsigned long, unsigned long);
+static psci_fn *invoke_psci_fn;
+
+static struct psci_0_1_function_ids psci_0_1_function_ids;
+
+struct psci_0_1_function_ids get_psci_0_1_function_ids(void)
+{
+	return psci_0_1_function_ids;
+}
+
+#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;
+}
+
+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 __always_inline 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 __always_inline 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 __always_inline 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_0_1_get_version(void)
+{
+	return PSCI_VERSION(0, 1);
+}
+
+static u32 psci_0_2_get_version(void)
+{
+	return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
+}
+
+int psci_set_osi_mode(bool enable)
+{
+	unsigned long suspend_mode;
+	int err;
+
+	suspend_mode = enable ? PSCI_1_0_SUSPEND_MODE_OSI :
+			PSCI_1_0_SUSPEND_MODE_PC;
+
+	err = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE, suspend_mode, 0, 0);
+	if (err < 0)
+		pr_info(FW_BUG "failed to set %s mode: %d\n",
+				enable ? "OSI" : "PC", err);
+	return psci_to_linux_errno(err);
+}
+
+static __always_inline int
+__psci_cpu_suspend(u32 fn, u32 state, unsigned long entry_point)
+{
+	int err;
+
+	err = invoke_psci_fn(fn, state, entry_point, 0);
+	return psci_to_linux_errno(err);
+}
+
+static __always_inline int
+psci_0_1_cpu_suspend(u32 state, unsigned long entry_point)
+{
+	return __psci_cpu_suspend(psci_0_1_function_ids.cpu_suspend,
+				  state, entry_point);
+}
+
+static __always_inline int
+psci_0_2_cpu_suspend(u32 state, unsigned long entry_point)
+{
+	return __psci_cpu_suspend(PSCI_FN_NATIVE(0_2, CPU_SUSPEND),
+				  state, entry_point);
+}
+
+static int __psci_cpu_off(u32 fn, u32 state)
+{
+	int err;
+
+	err = invoke_psci_fn(fn, state, 0, 0);
+	return psci_to_linux_errno(err);
+}
+
+static int psci_0_1_cpu_off(u32 state)
+{
+	return __psci_cpu_off(psci_0_1_function_ids.cpu_off, state);
+}
+
+static int psci_0_2_cpu_off(u32 state)
+{
+	return __psci_cpu_off(PSCI_0_2_FN_CPU_OFF, state);
+}
+
+static int __psci_cpu_on(u32 fn, unsigned long cpuid, unsigned long entry_point)
+{
+	int err;
+
+	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
+	return psci_to_linux_errno(err);
+}
+
+static int psci_0_1_cpu_on(unsigned long cpuid, unsigned long entry_point)
+{
+	return __psci_cpu_on(psci_0_1_function_ids.cpu_on, cpuid, entry_point);
+}
+
+static int psci_0_2_cpu_on(unsigned long cpuid, unsigned long entry_point)
+{
+	return __psci_cpu_on(PSCI_FN_NATIVE(0_2, CPU_ON), cpuid, entry_point);
+}
+
+static int __psci_migrate(u32 fn, unsigned long cpuid)
+{
+	int err;
+
+	err = invoke_psci_fn(fn, cpuid, 0, 0);
+	return psci_to_linux_errno(err);
+}
+
+static int psci_0_1_migrate(unsigned long cpuid)
+{
+	return __psci_migrate(psci_0_1_function_ids.migrate, cpuid);
+}
+
+static int psci_0_2_migrate(unsigned long cpuid)
+{
+	return __psci_migrate(PSCI_FN_NATIVE(0_2, MIGRATE), cpuid);
+}
+
+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 arm_smccc_conduit conduit)
+{
+	switch (conduit) {
+	case SMCCC_CONDUIT_HVC:
+		invoke_psci_fn = __invoke_psci_fn_hvc;
+		break;
+	case SMCCC_CONDUIT_SMC:
+		invoke_psci_fn = __invoke_psci_fn_smc;
+		break;
+	default:
+		WARN(1, "Unexpected PSCI conduit %d\n", conduit);
+	}
+
+	psci_conduit = conduit;
+}
+
+static int get_set_conduit_method(const 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(SMCCC_CONDUIT_HVC);
+	} else if (!strcmp("smc", method)) {
+		set_conduit(SMCCC_CONDUIT_SMC);
+	} else {
+		pr_warn("invalid \"method\" property: %s\n", method);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int psci_sys_reset(struct notifier_block *nb, unsigned long action,
+			  void *data)
+{
+	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);
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block psci_sys_reset_nb = {
+	.notifier_call = psci_sys_reset,
+	.priority = 129,
+};
+
+static void psci_sys_poweroff(void)
+{
+	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
+}
+
+static int psci_features(u32 psci_func_id)
+{
+	return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
+			      psci_func_id, 0, 0);
+}
+
+#ifdef CONFIG_DEBUG_FS
+
+#define PSCI_ID(ver, _name) \
+	{ .fn = PSCI_##ver##_FN_##_name, .name = #_name, }
+#define PSCI_ID_NATIVE(ver, _name) \
+	{ .fn = PSCI_FN_NATIVE(ver, _name), .name = #_name, }
+
+/* A table of all optional functions */
+static const struct {
+	u32 fn;
+	const char *name;
+} psci_fn_ids[] = {
+	PSCI_ID_NATIVE(0_2, MIGRATE),
+	PSCI_ID(0_2, MIGRATE_INFO_TYPE),
+	PSCI_ID_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
+	PSCI_ID(1_0, CPU_FREEZE),
+	PSCI_ID_NATIVE(1_0, CPU_DEFAULT_SUSPEND),
+	PSCI_ID_NATIVE(1_0, NODE_HW_STATE),
+	PSCI_ID_NATIVE(1_0, SYSTEM_SUSPEND),
+	PSCI_ID(1_0, SET_SUSPEND_MODE),
+	PSCI_ID_NATIVE(1_0, STAT_RESIDENCY),
+	PSCI_ID_NATIVE(1_0, STAT_COUNT),
+	PSCI_ID_NATIVE(1_1, SYSTEM_RESET2),
+	PSCI_ID(1_1, MEM_PROTECT),
+	PSCI_ID_NATIVE(1_1, MEM_PROTECT_CHECK_RANGE),
+};
+
+static int psci_debugfs_read(struct seq_file *s, void *data)
+{
+	int feature, type, i;
+	u32 ver;
+
+	ver = psci_ops.get_version();
+	seq_printf(s, "PSCIv%d.%d\n",
+		   PSCI_VERSION_MAJOR(ver),
+		   PSCI_VERSION_MINOR(ver));
+
+	/* PSCI_FEATURES is available only starting from 1.0 */
+	if (PSCI_VERSION_MAJOR(ver) < 1)
+		return 0;
+
+	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
+	if (feature != PSCI_RET_NOT_SUPPORTED) {
+		ver = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
+		seq_printf(s, "SMC Calling Convention v%d.%d\n",
+			   PSCI_VERSION_MAJOR(ver),
+			   PSCI_VERSION_MINOR(ver));
+	} else {
+		seq_puts(s, "SMC Calling Convention v1.0 is assumed\n");
+	}
+
+	feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));
+	if (feature < 0) {
+		seq_printf(s, "PSCI_FEATURES(CPU_SUSPEND) error (%d)\n", feature);
+	} else {
+		seq_printf(s, "OSI is %ssupported\n",
+			   (feature & BIT(0)) ? "" : "not ");
+		seq_printf(s, "%s StateID format is used\n",
+			   (feature & BIT(1)) ? "Extended" : "Original");
+	}
+
+	type = psci_ops.migrate_info_type();
+	if (type == PSCI_0_2_TOS_UP_MIGRATE ||
+	    type == PSCI_0_2_TOS_UP_NO_MIGRATE) {
+		unsigned long cpuid;
+
+		seq_printf(s, "Trusted OS %smigrate capable\n",
+			   type == PSCI_0_2_TOS_UP_NO_MIGRATE ? "not " : "");
+		cpuid = psci_migrate_info_up_cpu();
+		seq_printf(s, "Trusted OS resident on physical CPU 0x%lx (#%d)\n",
+			   cpuid, resident_cpu);
+	} else if (type == PSCI_0_2_TOS_MP) {
+		seq_puts(s, "Trusted OS migration not required\n");
+	} else {
+		if (type != PSCI_RET_NOT_SUPPORTED)
+			seq_printf(s, "MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(psci_fn_ids); i++) {
+		feature = psci_features(psci_fn_ids[i].fn);
+		if (feature == PSCI_RET_NOT_SUPPORTED)
+			continue;
+		if (feature < 0)
+			seq_printf(s, "PSCI_FEATURES(%s) error (%d)\n",
+				   psci_fn_ids[i].name, feature);
+		else
+			seq_printf(s, "%s is supported\n", psci_fn_ids[i].name);
+	}
+
+	return 0;
+}
+
+static int psci_debugfs_open(struct inode *inode, struct file *f)
+{
+	return single_open(f, psci_debugfs_read, NULL);
+}
+
+static const struct file_operations psci_debugfs_ops = {
+	.owner = THIS_MODULE,
+	.open = psci_debugfs_open,
+	.release = single_release,
+	.read = seq_read,
+	.llseek = seq_lseek
+};
+
+static int __init psci_debugfs_init(void)
+{
+	if (!invoke_psci_fn || !psci_ops.get_version)
+		return 0;
+
+	return PTR_ERR_OR_ZERO(debugfs_create_file("psci", 0444, NULL, NULL,
+						   &psci_debugfs_ops));
+}
+late_initcall(psci_debugfs_init)
+#endif
+
+#ifdef CONFIG_CPU_IDLE
+static noinstr int psci_suspend_finisher(unsigned long state)
+{
+	u32 power_state = state;
+	phys_addr_t pa_cpu_resume;
+
+	pa_cpu_resume = __pa_symbol_nodebug((unsigned long)cpu_resume);
+
+	return psci_ops.cpu_suspend(power_state, pa_cpu_resume);
+}
+
+int psci_cpu_suspend_enter(u32 state)
+{
+	int ret;
+
+	if (!psci_power_state_loses_context(state)) {
+		struct arm_cpuidle_irq_context context;
+
+		ct_cpuidle_enter();
+		arm_cpuidle_save_irq_context(&context);
+		ret = psci_ops.cpu_suspend(state, 0);
+		arm_cpuidle_restore_irq_context(&context);
+		ct_cpuidle_exit();
+	} else {
+		/*
+		 * ARM64 cpu_suspend() wants to do ct_cpuidle_*() itself.
+		 */
+		if (!IS_ENABLED(CONFIG_ARM64))
+			ct_cpuidle_enter();
+
+		ret = cpu_suspend(state, psci_suspend_finisher);
+
+		if (!IS_ENABLED(CONFIG_ARM64))
+			ct_cpuidle_exit();
+	}
+
+	return ret;
+}
+#endif
+
+static int psci_system_suspend(unsigned long unused)
+{
+	phys_addr_t pa_cpu_resume = __pa_symbol(cpu_resume);
+
+	return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
+			      pa_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_FN_NATIVE(0_2, 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) {
+			arm_smccc_version_init(ret, psci_conduit);
+			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 = (struct psci_operations){
+		.get_version = psci_0_2_get_version,
+		.cpu_suspend = psci_0_2_cpu_suspend,
+		.cpu_off = psci_0_2_cpu_off,
+		.cpu_on = psci_0_2_cpu_on,
+		.migrate = psci_0_2_migrate,
+		.affinity_info = psci_affinity_info,
+		.migrate_info_type = psci_migrate_info_type,
+	};
+
+	register_restart_handler(&psci_sys_reset_nb);
+
+	pm_power_off = psci_sys_poweroff;
+}
+
+/*
+ * Probe function for PSCI firmware versions >= 0.2
+ */
+static int __init psci_probe(void)
+{
+	u32 ver = psci_0_2_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();
+		kvm_init_hyp_services();
+	}
+
+	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(const 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(const 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");
+
+	psci_ops.get_version = psci_0_1_get_version;
+
+	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
+		psci_0_1_function_ids.cpu_suspend = id;
+		psci_ops.cpu_suspend = psci_0_1_cpu_suspend;
+	}
+
+	if (!of_property_read_u32(np, "cpu_off", &id)) {
+		psci_0_1_function_ids.cpu_off = id;
+		psci_ops.cpu_off = psci_0_1_cpu_off;
+	}
+
+	if (!of_property_read_u32(np, "cpu_on", &id)) {
+		psci_0_1_function_ids.cpu_on = id;
+		psci_ops.cpu_on = psci_0_1_cpu_on;
+	}
+
+	if (!of_property_read_u32(np, "migrate", &id)) {
+		psci_0_1_function_ids.migrate = id;
+		psci_ops.migrate = psci_0_1_migrate;
+	}
+
+	return 0;
+}
+
+static int __init psci_1_0_init(const 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");
+
+		/* Default to PC mode. */
+		psci_set_osi_mode(false);
+	}
+
+	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(SMCCC_CONDUIT_HVC);
+	else
+		set_conduit(SMCCC_CONDUIT_SMC);
+
+	return psci_probe();
+}
+#endif