arm64: psci: factor invocation code to drivers

To enable sharing with arm, move the core PSCI framework code to
drivers/firmware. This results in a minor gain in lines of code, but
this will quickly be amortised by the removal of code currently
duplicated in arch/arm.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
(cherry picked from commit bff60792f994a87324ab57e89e945b4572b1ef77)
Signed-off-by: Alex Shi <alex.shi@linaro.org>

9 files changed, 431 insertions, 390 deletions

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 57424682c723..1eb7539aa583 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -19,6 +19,7 @@ config ARM64
 	select ARM_GIC_V2M if PCI_MSI
 	select ARM_GIC_V3
 	select ARM_GIC_V3_ITS if PCI_MSI
+	select ARM_PSCI_FW
 	select BUILDTIME_EXTABLE_SORT
 	select CLONE_BACKWARDS
 	select COMMON_CLK
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 39248d3adf5d..ed7e212c893c 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -12,11 +12,11 @@
 #ifndef _ASM_ACPI_H
 #define _ASM_ACPI_H
 
-#include <linux/mm.h>
 #include <linux/irqchip/arm-gic-acpi.h>
+#include <linux/mm.h>
+#include <linux/psci.h>
 
 #include <asm/cputype.h>
-#include <asm/psci.h>
 #include <asm/smp_plat.h>
 
 /* Basic configuration for ACPI */
diff --git a/arch/arm64/include/asm/psci.h b/arch/arm64/include/asm/psci.h
deleted file mode 100644
index 49d7e1aaebdc..000000000000
--- a/arch/arm64/include/asm/psci.h
+++ /dev/null
@@ -1,28 +0,0 @@
-/*
- * 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
- */
-
-#ifndef __ASM_PSCI_H
-#define __ASM_PSCI_H
-
-int __init psci_dt_init(void);
-
-#ifdef CONFIG_ACPI
-int __init psci_acpi_init(void);
-bool __init acpi_psci_present(void);
-bool __init acpi_psci_use_hvc(void);
-#else
-static inline int psci_acpi_init(void) { return 0; }
-static inline bool acpi_psci_present(void) { return false; }
-#endif
-
-#endif /* __ASM_PSCI_H */
diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
index ec30152090ae..aa94a88f6279 100644
--- a/arch/arm64/kernel/psci.c
+++ b/arch/arm64/kernel/psci.c
@@ -18,23 +18,17 @@
 #include <linux/init.h>
 #include <linux/of.h>
 #include <linux/smp.h>
-#include <linux/reboot.h>
-#include <linux/pm.h>
 #include <linux/delay.h>
+#include <linux/psci.h>
 #include <linux/slab.h>
+
 #include <uapi/linux/psci.h>
 
 #include <asm/compiler.h>
-#include <asm/cputype.h>
 #include <asm/cpu_ops.h>
 #include <asm/errno.h>
-#include <asm/psci.h>
 #include <asm/smp_plat.h>
 #include <asm/suspend.h>
-#include <asm/system_misc.h>
-
-#define PSCI_POWER_STATE_TYPE_STANDBY		0
-#define PSCI_POWER_STATE_TYPE_POWER_DOWN	1
 
 static bool psci_power_state_loses_context(u32 state)
 {
@@ -50,122 +44,8 @@ static bool psci_power_state_is_valid(u32 state)
 	return !(state & ~valid_mask);
 }
 
-/*
- * 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 {
-	int (*cpu_suspend)(u32 state, unsigned long entry_point);
-	int (*cpu_off)(u32 state);
-	int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
-	int (*migrate)(unsigned long cpuid);
-	int (*affinity_info)(unsigned long target_affinity,
-			unsigned long lowest_affinity_level);
-	int (*migrate_info_type)(void);
-};
-
-static struct psci_operations psci_ops;
-
-typedef unsigned long (psci_fn)(unsigned long, unsigned long,
-				unsigned long, unsigned long);
-asmlinkage psci_fn __invoke_psci_fn_hvc;
-asmlinkage psci_fn __invoke_psci_fn_smc;
-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 DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
 
-static u32 psci_function_id[PSCI_FN_MAX];
-
-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:
-		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_0_2_FN64_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_0_2_FN64_MIGRATE_INFO_UP_CPU, 0, 0, 0);
-}
-
 static int __maybe_unused cpu_psci_cpu_init_idle(unsigned int cpu)
 {
 	int i, ret, count = 0;
@@ -230,238 +110,6 @@ free_mem:
 	return ret;
 }
 
-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)) {
-		invoke_psci_fn = __invoke_psci_fn_hvc;
-	} else if (!strcmp("smc", method)) {
-		invoke_psci_fn = __invoke_psci_fn_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)
-{
-	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);
-}
-
-/*
- * 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;
-
-	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_0_2_set_functions(void)
-{
-	pr_info("Using standard PSCI v0.2 function IDs\n");
-	psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN64_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_0_2_FN64_CPU_ON;
-	psci_ops.cpu_on = psci_cpu_on;
-
-	psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_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();
-
-	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)
-		goto out_put_node;
-	/*
-	 * 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
-	 */
-	err = psci_probe();
-
-out_put_node:
-	of_node_put(np);
-	return err;
-}
-
-/*
- * 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)
-		goto out_put_node;
-
-	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;
-	}
-
-out_put_node:
-	of_node_put(np);
-	return err;
-}
-
-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},
-	{},
-};
-
-int __init psci_dt_init(void)
-{
-	struct device_node *np;
-	const struct of_device_id *matched_np;
-	psci_initcall_t init_fn;
-
-	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
-
-	if (!np)
-		return -ENODEV;
-
-	init_fn = (psci_initcall_t)matched_np->data;
-	return init_fn(np);
-}
-
-#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())
-		invoke_psci_fn = __invoke_psci_fn_hvc;
-	else
-		invoke_psci_fn = __invoke_psci_fn_smc;
-
-	return psci_probe();
-}
-#endif
-
 static int __init cpu_psci_cpu_init(unsigned int cpu)
 {
 	return 0;
@@ -487,11 +135,6 @@ static int cpu_psci_cpu_boot(unsigned int cpu)
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-static bool psci_tos_resident_on(int cpu)
-{
-	return cpu == resident_cpu;
-}
-
 static int cpu_psci_cpu_disable(unsigned int cpu)
 {
 	/* Fail early if we don't have CPU_OFF support */
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index a510ebf99af8..e5202836dc64 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -46,6 +46,7 @@
 #include <linux/of_platform.h>
 #include <linux/efi.h>
 #include <linux/personality.h>
+#include <linux/psci.h>
 
 #include <asm/acpi.h>
 #include <asm/fixmap.h>
@@ -61,7 +62,6 @@
 #include <asm/tlbflush.h>
 #include <asm/traps.h>
 #include <asm/memblock.h>
-#include <asm/psci.h>
 #include <asm/efi.h>
 #include <asm/virt.h>
 
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 6517132e5d8b..24be7a34b84a 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -5,6 +5,9 @@
 
 menu "Firmware Drivers"
 
+config ARM_PSCI_FW
+	bool
+
 config EDD
 	tristate "BIOS Enhanced Disk Drive calls determine boot disk"
 	depends on X86
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index 3fdd3912709a..6b051293e689 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -1,6 +1,7 @@
 #
 # Makefile for the linux kernel.
 #
+obj-$(CONFIG_ARM_PSCI_FW)	+= psci.o
 obj-$(CONFIG_DMI)		+= dmi_scan.o
 obj-$(CONFIG_DMI_SYSFS)		+= dmi-sysfs.o
 obj-$(CONFIG_EDD)		+= edd.o
diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
new file mode 100644
index 000000000000..36e2cea3809b
--- /dev/null
+++ b/drivers/firmware/psci.c
@@ -0,0 +1,369 @@
+/*
+ * 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) 2015 ARM Limited
+ */
+
+#define pr_fmt(fmt) "psci: " fmt
+
+#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 <uapi/linux/psci.h>
+
+#include <asm/cputype.h>
+#include <asm/system_misc.h>
+#include <asm/smp_plat.h>
+
+/*
+ * 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;
+
+typedef unsigned long (psci_fn)(unsigned long, unsigned long,
+				unsigned long, unsigned long);
+asmlinkage psci_fn __invoke_psci_fn_hvc;
+asmlinkage psci_fn __invoke_psci_fn_smc;
+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];
+
+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:
+		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_0_2_FN64_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_0_2_FN64_MIGRATE_INFO_UP_CPU, 0, 0, 0);
+}
+
+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)) {
+		invoke_psci_fn = __invoke_psci_fn_hvc;
+	} else if (!strcmp("smc", method)) {
+		invoke_psci_fn = __invoke_psci_fn_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)
+{
+	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);
+}
+
+/*
+ * 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_0_2_set_functions(void)
+{
+	pr_info("Using standard PSCI v0.2 function IDs\n");
+	psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN64_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_0_2_FN64_CPU_ON;
+	psci_ops.cpu_on = psci_cpu_on;
+
+	psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_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();
+
+	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)
+		goto out_put_node;
+	/*
+	 * 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
+	 */
+	err = psci_probe();
+
+out_put_node:
+	of_node_put(np);
+	return err;
+}
+
+/*
+ * 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)
+		goto out_put_node;
+
+	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;
+	}
+
+out_put_node:
+	of_node_put(np);
+	return err;
+}
+
+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},
+	{},
+};
+
+int __init psci_dt_init(void)
+{
+	struct device_node *np;
+	const struct of_device_id *matched_np;
+	psci_initcall_t init_fn;
+
+	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
+
+	if (!np)
+		return -ENODEV;
+
+	init_fn = (psci_initcall_t)matched_np->data;
+	return init_fn(np);
+}
+
+#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())
+		invoke_psci_fn = __invoke_psci_fn_hvc;
+	else
+		invoke_psci_fn = __invoke_psci_fn_smc;
+
+	return psci_probe();
+}
+#endif
diff --git a/include/linux/psci.h b/include/linux/psci.h
new file mode 100644
index 000000000000..a682fcc91c33
--- /dev/null
+++ b/include/linux/psci.h
@@ -0,0 +1,52 @@
+/*
+ * 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) 2015 ARM Limited
+ */
+
+#ifndef __LINUX_PSCI_H
+#define __LINUX_PSCI_H
+
+#include <linux/init.h>
+#include <linux/types.h>
+
+#define PSCI_POWER_STATE_TYPE_STANDBY		0
+#define PSCI_POWER_STATE_TYPE_POWER_DOWN	1
+
+bool psci_tos_resident_on(int cpu);
+
+struct psci_operations {
+	int (*cpu_suspend)(u32 state, unsigned long entry_point);
+	int (*cpu_off)(u32 state);
+	int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
+	int (*migrate)(unsigned long cpuid);
+	int (*affinity_info)(unsigned long target_affinity,
+			unsigned long lowest_affinity_level);
+	int (*migrate_info_type)(void);
+};
+
+extern struct psci_operations psci_ops;
+
+#if defined(CONFIG_ARM_PSCI_FW)
+int __init psci_dt_init(void);
+#else
+static inline int psci_dt_init(void) { return 0; }
+#endif
+
+#if defined(CONFIG_ARM_PSCI_FW) && defined(CONFIG_ACPI)
+int __init psci_acpi_init(void);
+bool __init acpi_psci_present(void);
+bool __init acpi_psci_use_hvc(void);
+#else
+static inline int psci_acpi_init(void) { return 0; }
+static inline bool acpi_psci_present(void) { return false; }
+#endif
+
+#endif /* __LINUX_PSCI_H */