// 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/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 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_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);
        return psci_to_linux_errno(err);
}

static 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 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 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(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 __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;
        phys_addr_t pa_cpu_resume = __pa_symbol(function_nocfi(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;

                arm_cpuidle_save_irq_context(&context);
                ret = psci_ops.cpu_suspend(state, 0);
                arm_cpuidle_restore_irq_context(&context);
        } else {
                ret = cpu_suspend(state, psci_suspend_finisher);
        }

        return ret;
}
#endif

static int psci_system_suspend(unsigned long unused)
{
        phys_addr_t pa_cpu_resume = __pa_symbol(function_nocfi(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(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");

        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(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