/* Copyright (c) 2015, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only 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.
 */

#include <linux/io.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/qcom_scm.h>
#include <linux/arm-smccc.h>
#include <linux/dma-mapping.h>

#include "qcom_scm.h"

#define QCOM_SCM_FNID(s, c) ((((s) & 0xFF) << 8) | ((c) & 0xFF))

#define MAX_QCOM_SCM_ARGS 10
#define MAX_QCOM_SCM_RETS 3

enum qcom_scm_arg_types {
        QCOM_SCM_VAL,
        QCOM_SCM_RO,
        QCOM_SCM_RW,
        QCOM_SCM_BUFVAL,
};

#define QCOM_SCM_ARGS_IMPL(num, a, b, c, d, e, f, g, h, i, j, ...) (\
                           (((a) & 0x3) << 4) | \
                           (((b) & 0x3) << 6) | \
                           (((c) & 0x3) << 8) | \
                           (((d) & 0x3) << 10) | \
                           (((e) & 0x3) << 12) | \
                           (((f) & 0x3) << 14) | \
                           (((g) & 0x3) << 16) | \
                           (((h) & 0x3) << 18) | \
                           (((i) & 0x3) << 20) | \
                           (((j) & 0x3) << 22) | \
                           ((num) & 0xf))

#define QCOM_SCM_ARGS(...) QCOM_SCM_ARGS_IMPL(__VA_ARGS__, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)

/**
 * struct qcom_scm_desc
 * @arginfo:    Metadata describing the arguments in args[]
 * @args:       The array of arguments for the secure syscall
 * @res:        The values returned by the secure syscall
 */
struct qcom_scm_desc {
        u32 arginfo;
        u64 args[MAX_QCOM_SCM_ARGS];
};

static u64 qcom_smccc_convention = -1;
static DEFINE_MUTEX(qcom_scm_lock);

#define QCOM_SCM_EBUSY_WAIT_MS 30
#define QCOM_SCM_EBUSY_MAX_RETRY 20

#define N_EXT_QCOM_SCM_ARGS 7
#define FIRST_EXT_ARG_IDX 3
#define N_REGISTER_ARGS (MAX_QCOM_SCM_ARGS - N_EXT_QCOM_SCM_ARGS + 1)

/**
 * qcom_scm_call() - Invoke a syscall in the secure world
 * @dev:        device
 * @svc_id:     service identifier
 * @cmd_id:     command identifier
 * @desc:       Descriptor structure containing arguments and return values
 *
 * Sends a command to the SCM and waits for the command to finish processing.
 * This should *only* be called in pre-emptible context.
*/
static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id,
                         const struct qcom_scm_desc *desc,
                         struct arm_smccc_res *res)
{
        int arglen = desc->arginfo & 0xf;
        int retry_count = 0, i;
        u32 fn_id = QCOM_SCM_FNID(svc_id, cmd_id);
        u64 cmd, x5 = desc->args[FIRST_EXT_ARG_IDX];
        dma_addr_t args_phys = 0;
        void *args_virt = NULL;
        size_t alloc_len;

        if (unlikely(arglen > N_REGISTER_ARGS)) {
                alloc_len = N_EXT_QCOM_SCM_ARGS * sizeof(u64);
                args_virt = kzalloc(PAGE_ALIGN(alloc_len), GFP_KERNEL);

                if (!args_virt)
                        return -ENOMEM;

                if (qcom_smccc_convention == ARM_SMCCC_SMC_32) {
                        __le32 *args = args_virt;

                        for (i = 0; i < N_EXT_QCOM_SCM_ARGS; i++)
                                args[i] = cpu_to_le32(desc->args[i +
                                                      FIRST_EXT_ARG_IDX]);
                } else {
                        __le64 *args = args_virt;

                        for (i = 0; i < N_EXT_QCOM_SCM_ARGS; i++)
                                args[i] = cpu_to_le64(desc->args[i +
                                                      FIRST_EXT_ARG_IDX]);
                }

                args_phys = dma_map_single(dev, args_virt, alloc_len,
                                           DMA_TO_DEVICE);

                if (dma_mapping_error(dev, args_phys)) {
                        kfree(args_virt);
                        return -ENOMEM;
                }

                x5 = args_phys;
        }

        do {
                mutex_lock(&qcom_scm_lock);

                cmd = ARM_SMCCC_CALL_VAL(ARM_SMCCC_STD_CALL,
                                         qcom_smccc_convention,
                                         ARM_SMCCC_OWNER_SIP, fn_id);

                do {
                        arm_smccc_smc(cmd, desc->arginfo, desc->args[0],
                                      desc->args[1], desc->args[2], x5, 0, 0,
                                      res);
                } while (res->a0 == QCOM_SCM_INTERRUPTED);

                mutex_unlock(&qcom_scm_lock);

                if (res->a0 == QCOM_SCM_V2_EBUSY) {
                        if (retry_count++ > QCOM_SCM_EBUSY_MAX_RETRY)
                                break;
                        msleep(QCOM_SCM_EBUSY_WAIT_MS);
                }
        }  while (res->a0 == QCOM_SCM_V2_EBUSY);

        if (args_virt) {
                dma_unmap_single(dev, args_phys, alloc_len, DMA_TO_DEVICE);
                kfree(args_virt);
        }

        if (res->a0 < 0)
                return qcom_scm_remap_error(res->a0);

        return 0;
}

/**
 * qcom_scm_set_cold_boot_addr() - Set the cold boot address for cpus
 * @entry: Entry point function for the cpus
 * @cpus: The cpumask of cpus that will use the entry point
 *
 * Set the cold boot address of the cpus. Any cpu outside the supported
 * range would be removed from the cpu present mask.
 */
int __qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus)
{
        return -ENOTSUPP;
}

/**
 * qcom_scm_set_warm_boot_addr() - Set the warm boot address for cpus
 * @dev: Device pointer
 * @entry: Entry point function for the cpus
 * @cpus: The cpumask of cpus that will use the entry point
 *
 * Set the Linux entry point for the SCM to transfer control to when coming
 * out of a power down. CPU power down may be executed on cpuidle or hotplug.
 */
int __qcom_scm_set_warm_boot_addr(struct device *dev, void *entry,
                                  const cpumask_t *cpus)
{
        return -ENOTSUPP;
}

/**
 * qcom_scm_cpu_power_down() - Power down the cpu
 * @flags - Flags to flush cache
 *
 * This is an end point to power down cpu. If there was a pending interrupt,
 * the control would return from this function, otherwise, the cpu jumps to the
 * warm boot entry point set for this cpu upon reset.
 */
void __qcom_scm_cpu_power_down(u32 flags)
{
}

int __qcom_scm_is_call_available(struct device *dev, u32 svc_id, u32 cmd_id)
{
        int ret;
        struct qcom_scm_desc desc = {0};
        struct arm_smccc_res res;

        desc.arginfo = QCOM_SCM_ARGS(1);
        desc.args[0] = QCOM_SCM_FNID(svc_id, cmd_id) |
                        (ARM_SMCCC_OWNER_SIP << ARM_SMCCC_OWNER_SHIFT);

        ret = qcom_scm_call(dev, QCOM_SCM_SVC_INFO, QCOM_IS_CALL_AVAIL_CMD,
                            &desc, &res);

        return ret ? : res.a1;
}

int __qcom_scm_hdcp_req(struct device *dev, struct qcom_scm_hdcp_req *req,
                        u32 req_cnt, u32 *resp)
{
        int ret;
        struct qcom_scm_desc desc = {0};
        struct arm_smccc_res res;

        if (req_cnt > QCOM_SCM_HDCP_MAX_REQ_CNT)
                return -ERANGE;

        desc.args[0] = req[0].addr;
        desc.args[1] = req[0].val;
        desc.args[2] = req[1].addr;
        desc.args[3] = req[1].val;
        desc.args[4] = req[2].addr;
        desc.args[5] = req[2].val;
        desc.args[6] = req[3].addr;
        desc.args[7] = req[3].val;
        desc.args[8] = req[4].addr;
        desc.args[9] = req[4].val;
        desc.arginfo = QCOM_SCM_ARGS(10);

        ret = qcom_scm_call(dev, QCOM_SCM_SVC_HDCP, QCOM_SCM_CMD_HDCP, &desc,
                            &res);
        *resp = res.a1;

        return ret;
}

void __qcom_scm_init(void)
{
        u64 cmd;
        struct arm_smccc_res res;
        u32 function = QCOM_SCM_FNID(QCOM_SCM_SVC_INFO, QCOM_IS_CALL_AVAIL_CMD);

        /* First try a SMC64 call */
        cmd = ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64,
                                 ARM_SMCCC_OWNER_SIP, function);

        arm_smccc_smc(cmd, QCOM_SCM_ARGS(1), cmd & (~BIT(ARM_SMCCC_TYPE_SHIFT)),
                      0, 0, 0, 0, 0, &res);

        if (!res.a0 && res.a1)
                qcom_smccc_convention = ARM_SMCCC_SMC_64;
        else
                qcom_smccc_convention = ARM_SMCCC_SMC_32;
}

bool __qcom_scm_pas_supported(struct device *dev, u32 peripheral)
{
        int ret;
        struct qcom_scm_desc desc = {0};
        struct arm_smccc_res res;

        desc.args[0] = peripheral;
        desc.arginfo = QCOM_SCM_ARGS(1);

        ret = qcom_scm_call(dev, QCOM_SCM_SVC_PIL,
                                QCOM_SCM_PAS_IS_SUPPORTED_CMD,
                                &desc, &res);

        return ret ? false : !!res.a1;
}

int __qcom_scm_pas_init_image(struct device *dev, u32 peripheral,
                              dma_addr_t metadata_phys)
{
        int ret;
        struct qcom_scm_desc desc = {0};
        struct arm_smccc_res res;

        desc.args[0] = peripheral;
        desc.args[1] = metadata_phys;
        desc.arginfo = QCOM_SCM_ARGS(2, QCOM_SCM_VAL, QCOM_SCM_RW);

        ret = qcom_scm_call(dev, QCOM_SCM_SVC_PIL, QCOM_SCM_PAS_INIT_IMAGE_CMD,
                                &desc, &res);

        return ret ? : res.a1;
}

int __qcom_scm_pas_mem_setup(struct device *dev, u32 peripheral,
                              phys_addr_t addr, phys_addr_t size)
{
        int ret;
        struct qcom_scm_desc desc = {0};
        struct arm_smccc_res res;

        desc.args[0] = peripheral;
        desc.args[1] = addr;
        desc.args[2] = size;
        desc.arginfo = QCOM_SCM_ARGS(3);

        ret = qcom_scm_call(dev, QCOM_SCM_SVC_PIL, QCOM_SCM_PAS_MEM_SETUP_CMD,
                                &desc, &res);

        return ret ? : res.a1;
}

int __qcom_scm_pas_auth_and_reset(struct device *dev, u32 peripheral)
{
        int ret;
        struct qcom_scm_desc desc = {0};
        struct arm_smccc_res res;

        desc.args[0] = peripheral;
        desc.arginfo = QCOM_SCM_ARGS(1);

        ret = qcom_scm_call(dev, QCOM_SCM_SVC_PIL,
                                QCOM_SCM_PAS_AUTH_AND_RESET_CMD,
                                &desc, &res);

        return ret ? : res.a1;
}

int __qcom_scm_pas_shutdown(struct device *dev, u32 peripheral)
{
        int ret;
        struct qcom_scm_desc desc = {0};
        struct arm_smccc_res res;

        desc.args[0] = peripheral;
        desc.arginfo = QCOM_SCM_ARGS(1);

        ret = qcom_scm_call(dev, QCOM_SCM_SVC_PIL, QCOM_SCM_PAS_SHUTDOWN_CMD,
                        &desc, &res);

        return ret ? : res.a1;
}

int __qcom_scm_pas_mss_reset(struct device *dev, bool reset)
{
        struct qcom_scm_desc desc = {0};
        struct arm_smccc_res res;
        int ret;

        desc.args[0] = reset;
        desc.args[1] = 0;
        desc.arginfo = QCOM_SCM_ARGS(2);

        ret = qcom_scm_call(dev, QCOM_SCM_SVC_PIL, QCOM_SCM_PAS_MSS_RESET, &desc,
                            &res);

        return ret ? : res.a1;
}