// SPDX-License-Identifier: GPL-2.0-only
/*
 * SBI initialilization and all extension implementation.
 *
 * Copyright (c) 2020 Western Digital Corporation or its affiliates.
 */

#include <linux/init.h>
#include <linux/pm.h>
#include <asm/sbi.h>
#include <asm/smp.h>

/* default SBI version is 0.1 */
unsigned long sbi_spec_version __ro_after_init = SBI_SPEC_VERSION_DEFAULT;
EXPORT_SYMBOL(sbi_spec_version);

static void (*__sbi_set_timer)(uint64_t stime) __ro_after_init;
static int (*__sbi_send_ipi)(const unsigned long *hart_mask) __ro_after_init;
static int (*__sbi_rfence)(int fid, const unsigned long *hart_mask,
                           unsigned long start, unsigned long size,
                           unsigned long arg4, unsigned long arg5) __ro_after_init;

struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
                        unsigned long arg1, unsigned long arg2,
                        unsigned long arg3, unsigned long arg4,
                        unsigned long arg5)
{
        struct sbiret ret;

        register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);
        register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);
        register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);
        register uintptr_t a3 asm ("a3") = (uintptr_t)(arg3);
        register uintptr_t a4 asm ("a4") = (uintptr_t)(arg4);
        register uintptr_t a5 asm ("a5") = (uintptr_t)(arg5);
        register uintptr_t a6 asm ("a6") = (uintptr_t)(fid);
        register uintptr_t a7 asm ("a7") = (uintptr_t)(ext);
        asm volatile ("ecall"
                      : "+r" (a0), "+r" (a1)
                      : "r" (a2), "r" (a3), "r" (a4), "r" (a5), "r" (a6), "r" (a7)
                      : "memory");
        ret.error = a0;
        ret.value = a1;

        return ret;
}
EXPORT_SYMBOL(sbi_ecall);

int sbi_err_map_linux_errno(int err)
{
        switch (err) {
        case SBI_SUCCESS:
                return 0;
        case SBI_ERR_DENIED:
                return -EPERM;
        case SBI_ERR_INVALID_PARAM:
                return -EINVAL;
        case SBI_ERR_INVALID_ADDRESS:
                return -EFAULT;
        case SBI_ERR_NOT_SUPPORTED:
        case SBI_ERR_FAILURE:
        default:
                return -ENOTSUPP;
        };
}
EXPORT_SYMBOL(sbi_err_map_linux_errno);

#ifdef CONFIG_RISCV_SBI_V01
/**
 * sbi_console_putchar() - Writes given character to the console device.
 * @ch: The data to be written to the console.
 *
 * Return: None
 */
void sbi_console_putchar(int ch)
{
        sbi_ecall(SBI_EXT_0_1_CONSOLE_PUTCHAR, 0, ch, 0, 0, 0, 0, 0);
}
EXPORT_SYMBOL(sbi_console_putchar);

/**
 * sbi_console_getchar() - Reads a byte from console device.
 *
 * Returns the value read from console.
 */
int sbi_console_getchar(void)
{
        struct sbiret ret;

        ret = sbi_ecall(SBI_EXT_0_1_CONSOLE_GETCHAR, 0, 0, 0, 0, 0, 0, 0);

        return ret.error;
}
EXPORT_SYMBOL(sbi_console_getchar);

/**
 * sbi_shutdown() - Remove all the harts from executing supervisor code.
 *
 * Return: None
 */
void sbi_shutdown(void)
{
        sbi_ecall(SBI_EXT_0_1_SHUTDOWN, 0, 0, 0, 0, 0, 0, 0);
}
EXPORT_SYMBOL(sbi_shutdown);

/**
 * sbi_clear_ipi() - Clear any pending IPIs for the calling hart.
 *
 * Return: None
 */
void sbi_clear_ipi(void)
{
        sbi_ecall(SBI_EXT_0_1_CLEAR_IPI, 0, 0, 0, 0, 0, 0, 0);
}
EXPORT_SYMBOL(sbi_clear_ipi);

/**
 * __sbi_set_timer_v01() - Program the timer for next timer event.
 * @stime_value: The value after which next timer event should fire.
 *
 * Return: None
 */
static void __sbi_set_timer_v01(uint64_t stime_value)
{
#if __riscv_xlen == 32
        sbi_ecall(SBI_EXT_0_1_SET_TIMER, 0, stime_value,
                  stime_value >> 32, 0, 0, 0, 0);
#else
        sbi_ecall(SBI_EXT_0_1_SET_TIMER, 0, stime_value, 0, 0, 0, 0, 0);
#endif
}

static int __sbi_send_ipi_v01(const unsigned long *hart_mask)
{
        sbi_ecall(SBI_EXT_0_1_SEND_IPI, 0, (unsigned long)hart_mask,
                  0, 0, 0, 0, 0);
        return 0;
}

static int __sbi_rfence_v01(int fid, const unsigned long *hart_mask,
                            unsigned long start, unsigned long size,
                            unsigned long arg4, unsigned long arg5)
{
        int result = 0;

        /* v0.2 function IDs are equivalent to v0.1 extension IDs */
        switch (fid) {
        case SBI_EXT_RFENCE_REMOTE_FENCE_I:
                sbi_ecall(SBI_EXT_0_1_REMOTE_FENCE_I, 0,
                          (unsigned long)hart_mask, 0, 0, 0, 0, 0);
                break;
        case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA:
                sbi_ecall(SBI_EXT_0_1_REMOTE_SFENCE_VMA, 0,
                          (unsigned long)hart_mask, start, size,
                          0, 0, 0);
                break;
        case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID:
                sbi_ecall(SBI_EXT_0_1_REMOTE_SFENCE_VMA_ASID, 0,
                          (unsigned long)hart_mask, start, size,
                          arg4, 0, 0);
                break;
        default:
                pr_err("SBI call [%d]not supported in SBI v0.1\n", fid);
                result = -EINVAL;
        }

        return result;
}

static void sbi_set_power_off(void)
{
        pm_power_off = sbi_shutdown;
}
#else
static void __sbi_set_timer_v01(uint64_t stime_value)
{
        pr_warn("Timer extension is not available in SBI v%lu.%lu\n",
                sbi_major_version(), sbi_minor_version());
}

static int __sbi_send_ipi_v01(const unsigned long *hart_mask)
{
        pr_warn("IPI extension is not available in SBI v%lu.%lu\n",
                sbi_major_version(), sbi_minor_version());

        return 0;
}

static int __sbi_rfence_v01(int fid, const unsigned long *hart_mask,
                            unsigned long start, unsigned long size,
                            unsigned long arg4, unsigned long arg5)
{
        pr_warn("remote fence extension is not available in SBI v%lu.%lu\n",
                sbi_major_version(), sbi_minor_version());

        return 0;
}

static void sbi_set_power_off(void) {}
#endif /* CONFIG_RISCV_SBI_V01 */

static void __sbi_set_timer_v02(uint64_t stime_value)
{
#if __riscv_xlen == 32
        sbi_ecall(SBI_EXT_TIME, SBI_EXT_TIME_SET_TIMER, stime_value,
                  stime_value >> 32, 0, 0, 0, 0);
#else
        sbi_ecall(SBI_EXT_TIME, SBI_EXT_TIME_SET_TIMER, stime_value, 0,
                  0, 0, 0, 0);
#endif
}

static int __sbi_send_ipi_v02(const unsigned long *hart_mask)
{
        unsigned long hartid, hmask_val, hbase;
        struct cpumask tmask;
        struct sbiret ret = {0};
        int result;

        if (!hart_mask || !(*hart_mask)) {
                riscv_cpuid_to_hartid_mask(cpu_online_mask, &tmask);
                hart_mask = cpumask_bits(&tmask);
        }

        hmask_val = 0;
        hbase = 0;
        for_each_set_bit(hartid, hart_mask, NR_CPUS) {
                if (hmask_val && ((hbase + BITS_PER_LONG) <= hartid)) {
                        ret = sbi_ecall(SBI_EXT_IPI, SBI_EXT_IPI_SEND_IPI,
                                        hmask_val, hbase, 0, 0, 0, 0);
                        if (ret.error)
                                goto ecall_failed;
                        hmask_val = 0;
                        hbase = 0;
                }
                if (!hmask_val)
                        hbase = hartid;
                hmask_val |= 1UL << (hartid - hbase);
        }

        if (hmask_val) {
                ret = sbi_ecall(SBI_EXT_IPI, SBI_EXT_IPI_SEND_IPI,
                                hmask_val, hbase, 0, 0, 0, 0);
                if (ret.error)
                        goto ecall_failed;
        }

        return 0;

ecall_failed:
        result = sbi_err_map_linux_errno(ret.error);
        pr_err("%s: hbase = [%lu] hmask = [0x%lx] failed (error [%d])\n",
               __func__, hbase, hmask_val, result);
        return result;
}

static int __sbi_rfence_v02_call(unsigned long fid, unsigned long hmask_val,
                                 unsigned long hbase, unsigned long start,
                                 unsigned long size, unsigned long arg4,
                                 unsigned long arg5)
{
        struct sbiret ret = {0};
        int ext = SBI_EXT_RFENCE;
        int result = 0;

        switch (fid) {
        case SBI_EXT_RFENCE_REMOTE_FENCE_I:
                ret = sbi_ecall(ext, fid, hmask_val, hbase, 0, 0, 0, 0);
                break;
        case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA:
                ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
                                size, 0, 0);
                break;
        case SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID:
                ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
                                size, arg4, 0);
                break;

        case SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA:
                ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
                                size, 0, 0);
                break;
        case SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA_VMID:
                ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
                                size, arg4, 0);
                break;
        case SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA:
                ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
                                size, 0, 0);
                break;
        case SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID:
                ret = sbi_ecall(ext, fid, hmask_val, hbase, start,
                                size, arg4, 0);
                break;
        default:
                pr_err("unknown function ID [%lu] for SBI extension [%d]\n",
                       fid, ext);
                result = -EINVAL;
        }

        if (ret.error) {
                result = sbi_err_map_linux_errno(ret.error);
                pr_err("%s: hbase = [%lu] hmask = [0x%lx] failed (error [%d])\n",
                       __func__, hbase, hmask_val, result);
        }

        return result;
}

static int __sbi_rfence_v02(int fid, const unsigned long *hart_mask,
                            unsigned long start, unsigned long size,
                            unsigned long arg4, unsigned long arg5)
{
        unsigned long hmask_val, hartid, hbase;
        struct cpumask tmask;
        int result;

        if (!hart_mask || !(*hart_mask)) {
                riscv_cpuid_to_hartid_mask(cpu_online_mask, &tmask);
                hart_mask = cpumask_bits(&tmask);
        }

        hmask_val = 0;
        hbase = 0;
        for_each_set_bit(hartid, hart_mask, NR_CPUS) {
                if (hmask_val && ((hbase + BITS_PER_LONG) <= hartid)) {
                        result = __sbi_rfence_v02_call(fid, hmask_val, hbase,
                                                       start, size, arg4, arg5);
                        if (result)
                                return result;
                        hmask_val = 0;
                        hbase = 0;
                }
                if (!hmask_val)
                        hbase = hartid;
                hmask_val |= 1UL << (hartid - hbase);
        }

        if (hmask_val) {
                result = __sbi_rfence_v02_call(fid, hmask_val, hbase,
                                               start, size, arg4, arg5);
                if (result)
                        return result;
        }

        return 0;
}

/**
 * sbi_set_timer() - Program the timer for next timer event.
 * @stime_value: The value after which next timer event should fire.
 *
 * Return: None.
 */
void sbi_set_timer(uint64_t stime_value)
{
        __sbi_set_timer(stime_value);
}

/**
 * sbi_send_ipi() - Send an IPI to any hart.
 * @hart_mask: A cpu mask containing all the target harts.
 *
 * Return: 0 on success, appropriate linux error code otherwise.
 */
int sbi_send_ipi(const unsigned long *hart_mask)
{
        return __sbi_send_ipi(hart_mask);
}
EXPORT_SYMBOL(sbi_send_ipi);

/**
 * sbi_remote_fence_i() - Execute FENCE.I instruction on given remote harts.
 * @hart_mask: A cpu mask containing all the target harts.
 *
 * Return: 0 on success, appropriate linux error code otherwise.
 */
int sbi_remote_fence_i(const unsigned long *hart_mask)
{
        return __sbi_rfence(SBI_EXT_RFENCE_REMOTE_FENCE_I,
                            hart_mask, 0, 0, 0, 0);
}
EXPORT_SYMBOL(sbi_remote_fence_i);

/**
 * sbi_remote_sfence_vma() - Execute SFENCE.VMA instructions on given remote
 *                           harts for the specified virtual address range.
 * @hart_mask: A cpu mask containing all the target harts.
 * @start: Start of the virtual address
 * @size: Total size of the virtual address range.
 *
 * Return: 0 on success, appropriate linux error code otherwise.
 */
int sbi_remote_sfence_vma(const unsigned long *hart_mask,
                           unsigned long start,
                           unsigned long size)
{
        return __sbi_rfence(SBI_EXT_RFENCE_REMOTE_SFENCE_VMA,
                            hart_mask, start, size, 0, 0);
}
EXPORT_SYMBOL(sbi_remote_sfence_vma);

/**
 * sbi_remote_sfence_vma_asid() - Execute SFENCE.VMA instructions on given
 * remote harts for a virtual address range belonging to a specific ASID.
 *
 * @hart_mask: A cpu mask containing all the target harts.
 * @start: Start of the virtual address
 * @size: Total size of the virtual address range.
 * @asid: The value of address space identifier (ASID).
 *
 * Return: 0 on success, appropriate linux error code otherwise.
 */
int sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
                                unsigned long start,
                                unsigned long size,
                                unsigned long asid)
{
        return __sbi_rfence(SBI_EXT_RFENCE_REMOTE_SFENCE_VMA_ASID,
                            hart_mask, start, size, asid, 0);
}
EXPORT_SYMBOL(sbi_remote_sfence_vma_asid);

/**
 * sbi_remote_hfence_gvma() - Execute HFENCE.GVMA instructions on given remote
 *                         harts for the specified guest physical address range.
 * @hart_mask: A cpu mask containing all the target harts.
 * @start: Start of the guest physical address
 * @size: Total size of the guest physical address range.
 *
 * Return: None
 */
int sbi_remote_hfence_gvma(const unsigned long *hart_mask,
                           unsigned long start,
                           unsigned long size)
{
        return __sbi_rfence(SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA,
                            hart_mask, start, size, 0, 0);
}
EXPORT_SYMBOL_GPL(sbi_remote_hfence_gvma);

/**
 * sbi_remote_hfence_gvma_vmid() - Execute HFENCE.GVMA instructions on given
 * remote harts for a guest physical address range belonging to a specific VMID.
 *
 * @hart_mask: A cpu mask containing all the target harts.
 * @start: Start of the guest physical address
 * @size: Total size of the guest physical address range.
 * @vmid: The value of guest ID (VMID).
 *
 * Return: 0 if success, Error otherwise.
 */
int sbi_remote_hfence_gvma_vmid(const unsigned long *hart_mask,
                                unsigned long start,
                                unsigned long size,
                                unsigned long vmid)
{
        return __sbi_rfence(SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA_VMID,
                            hart_mask, start, size, vmid, 0);
}
EXPORT_SYMBOL(sbi_remote_hfence_gvma_vmid);

/**
 * sbi_remote_hfence_vvma() - Execute HFENCE.VVMA instructions on given remote
 *                           harts for the current guest virtual address range.
 * @hart_mask: A cpu mask containing all the target harts.
 * @start: Start of the current guest virtual address
 * @size: Total size of the current guest virtual address range.
 *
 * Return: None
 */
int sbi_remote_hfence_vvma(const unsigned long *hart_mask,
                           unsigned long start,
                           unsigned long size)
{
        return __sbi_rfence(SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA,
                            hart_mask, start, size, 0, 0);
}
EXPORT_SYMBOL(sbi_remote_hfence_vvma);

/**
 * sbi_remote_hfence_vvma_asid() - Execute HFENCE.VVMA instructions on given
 * remote harts for current guest virtual address range belonging to a specific
 * ASID.
 *
 * @hart_mask: A cpu mask containing all the target harts.
 * @start: Start of the current guest virtual address
 * @size: Total size of the current guest virtual address range.
 * @asid: The value of address space identifier (ASID).
 *
 * Return: None
 */
int sbi_remote_hfence_vvma_asid(const unsigned long *hart_mask,
                                unsigned long start,
                                unsigned long size,
                                unsigned long asid)
{
        return __sbi_rfence(SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID,
                            hart_mask, start, size, asid, 0);
}
EXPORT_SYMBOL(sbi_remote_hfence_vvma_asid);

/**
 * sbi_probe_extension() - Check if an SBI extension ID is supported or not.
 * @extid: The extension ID to be probed.
 *
 * Return: Extension specific nonzero value f yes, -ENOTSUPP otherwise.
 */
int sbi_probe_extension(int extid)
{
        struct sbiret ret;

        ret = sbi_ecall(SBI_EXT_BASE, SBI_EXT_BASE_PROBE_EXT, extid,
                        0, 0, 0, 0, 0);
        if (!ret.error)
                if (ret.value)
                        return ret.value;

        return -ENOTSUPP;
}
EXPORT_SYMBOL(sbi_probe_extension);

static long __sbi_base_ecall(int fid)
{
        struct sbiret ret;

        ret = sbi_ecall(SBI_EXT_BASE, fid, 0, 0, 0, 0, 0, 0);
        if (!ret.error)
                return ret.value;
        else
                return sbi_err_map_linux_errno(ret.error);
}

static inline long sbi_get_spec_version(void)
{
        return __sbi_base_ecall(SBI_EXT_BASE_GET_SPEC_VERSION);
}

static inline long sbi_get_firmware_id(void)
{
        return __sbi_base_ecall(SBI_EXT_BASE_GET_IMP_ID);
}

static inline long sbi_get_firmware_version(void)
{
        return __sbi_base_ecall(SBI_EXT_BASE_GET_IMP_VERSION);
}

long sbi_get_mvendorid(void)
{
        return __sbi_base_ecall(SBI_EXT_BASE_GET_MVENDORID);
}

long sbi_get_marchid(void)
{
        return __sbi_base_ecall(SBI_EXT_BASE_GET_MARCHID);
}

long sbi_get_mimpid(void)
{
        return __sbi_base_ecall(SBI_EXT_BASE_GET_MIMPID);
}

static void sbi_send_cpumask_ipi(const struct cpumask *target)
{
        struct cpumask hartid_mask;

        riscv_cpuid_to_hartid_mask(target, &hartid_mask);

        sbi_send_ipi(cpumask_bits(&hartid_mask));
}

static const struct riscv_ipi_ops sbi_ipi_ops = {
        .ipi_inject = sbi_send_cpumask_ipi
};

void __init sbi_init(void)
{
        int ret;

        sbi_set_power_off();
        ret = sbi_get_spec_version();
        if (ret > 0)
                sbi_spec_version = ret;

        pr_info("SBI specification v%lu.%lu detected\n",
                sbi_major_version(), sbi_minor_version());

        if (!sbi_spec_is_0_1()) {
                pr_info("SBI implementation ID=0x%lx Version=0x%lx\n",
                        sbi_get_firmware_id(), sbi_get_firmware_version());
                if (sbi_probe_extension(SBI_EXT_TIME) > 0) {
                        __sbi_set_timer = __sbi_set_timer_v02;
                        pr_info("SBI TIME extension detected\n");
                } else {
                        __sbi_set_timer = __sbi_set_timer_v01;
                }
                if (sbi_probe_extension(SBI_EXT_IPI) > 0) {
                        __sbi_send_ipi  = __sbi_send_ipi_v02;
                        pr_info("SBI IPI extension detected\n");
                } else {
                        __sbi_send_ipi  = __sbi_send_ipi_v01;
                }
                if (sbi_probe_extension(SBI_EXT_RFENCE) > 0) {
                        __sbi_rfence    = __sbi_rfence_v02;
                        pr_info("SBI RFENCE extension detected\n");
                } else {
                        __sbi_rfence    = __sbi_rfence_v01;
                }
        } else {
                __sbi_set_timer = __sbi_set_timer_v01;
                __sbi_send_ipi  = __sbi_send_ipi_v01;
                __sbi_rfence    = __sbi_rfence_v01;
        }

        riscv_set_ipi_ops(&sbi_ipi_ops);
}