diff options
Diffstat (limited to 'drivers/firmware/psci/psci.c')
| -rw-r--r-- | drivers/firmware/psci/psci.c | 791 |
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 |