// SPDX-License-Identifier: GPL-2.0
/*
 * Xilinx Zynq MPSoC Firmware layer for debugfs APIs
 *
 *  Copyright (C) 2014-2018 Xilinx, Inc.
 *
 *  Michal Simek <michal.simek@xilinx.com>
 *  Davorin Mista <davorin.mista@aggios.com>
 *  Jolly Shah <jollys@xilinx.com>
 *  Rajan Vaja <rajanv@xilinx.com>
 */

#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>

#include <linux/firmware/xlnx-zynqmp.h>
#include "zynqmp-debug.h"

#define PM_API_NAME_LEN                 50

struct pm_api_info {
        u32 api_id;
        char api_name[PM_API_NAME_LEN];
        char api_name_len;
};

static char debugfs_buf[PAGE_SIZE];

#define PM_API(id)               {id, #id, strlen(#id)}
static struct pm_api_info pm_api_list[] = {
        PM_API(PM_GET_API_VERSION),
        PM_API(PM_QUERY_DATA),
};

static struct dentry *firmware_debugfs_root;

/**
 * zynqmp_pm_argument_value() - Extract argument value from a PM-API request
 * @arg:        Entered PM-API argument in string format
 *
 * Return: Argument value in unsigned integer format on success
 *         0 otherwise
 */
static u64 zynqmp_pm_argument_value(char *arg)
{
        u64 value;

        if (!arg)
                return 0;

        if (!kstrtou64(arg, 0, &value))
                return value;

        return 0;
}

/**
 * get_pm_api_id() - Extract API-ID from a PM-API request
 * @pm_api_req:         Entered PM-API argument in string format
 * @pm_id:              API-ID
 *
 * Return: 0 on success else error code
 */
static int get_pm_api_id(char *pm_api_req, u32 *pm_id)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(pm_api_list) ; i++) {
                if (!strncasecmp(pm_api_req, pm_api_list[i].api_name,
                                 pm_api_list[i].api_name_len)) {
                        *pm_id = pm_api_list[i].api_id;
                        break;
                }
        }

        /* If no name was entered look for PM-API ID instead */
        if (i == ARRAY_SIZE(pm_api_list) && kstrtouint(pm_api_req, 10, pm_id))
                return -EINVAL;

        return 0;
}

static int process_api_request(u32 pm_id, u64 *pm_api_arg, u32 *pm_api_ret)
{
        u32 pm_api_version;
        int ret;
        struct zynqmp_pm_query_data qdata = {0};

        switch (pm_id) {
        case PM_GET_API_VERSION:
                ret = zynqmp_pm_get_api_version(&pm_api_version);
                sprintf(debugfs_buf, "PM-API Version = %d.%d\n",
                        pm_api_version >> 16, pm_api_version & 0xffff);
                break;
        case PM_QUERY_DATA:
                qdata.qid = pm_api_arg[0];
                qdata.arg1 = pm_api_arg[1];
                qdata.arg2 = pm_api_arg[2];
                qdata.arg3 = pm_api_arg[3];

                ret = zynqmp_pm_query_data(qdata, pm_api_ret);
                if (ret)
                        break;

                switch (qdata.qid) {
                case PM_QID_CLOCK_GET_NAME:
                        sprintf(debugfs_buf, "Clock name = %s\n",
                                (char *)pm_api_ret);
                        break;
                case PM_QID_CLOCK_GET_FIXEDFACTOR_PARAMS:
                        sprintf(debugfs_buf, "Multiplier = %d, Divider = %d\n",
                                pm_api_ret[1], pm_api_ret[2]);
                        break;
                default:
                        sprintf(debugfs_buf,
                                "data[0] = 0x%08x\ndata[1] = 0x%08x\n data[2] = 0x%08x\ndata[3] = 0x%08x\n",
                                pm_api_ret[0], pm_api_ret[1],
                                pm_api_ret[2], pm_api_ret[3]);
                }
                break;
        default:
                sprintf(debugfs_buf, "Unsupported PM-API request\n");
                ret = -EINVAL;
        }

        return ret;
}

/**
 * zynqmp_pm_debugfs_api_write() - debugfs write function
 * @file:       User file
 * @ptr:        User entered PM-API string
 * @len:        Length of the userspace buffer
 * @off:        Offset within the file
 *
 * Used for triggering pm api functions by writing
 * echo <pm_api_id>     > /sys/kernel/debug/zynqmp_pm/power or
 * echo <pm_api_name>   > /sys/kernel/debug/zynqmp_pm/power
 *
 * Return: Number of bytes copied if PM-API request succeeds,
 *         the corresponding error code otherwise
 */
static ssize_t zynqmp_pm_debugfs_api_write(struct file *file,
                                           const char __user *ptr, size_t len,
                                           loff_t *off)
{
        char *kern_buff, *tmp_buff;
        char *pm_api_req;
        u32 pm_id = 0;
        u64 pm_api_arg[4] = {0, 0, 0, 0};
        /* Return values from PM APIs calls */
        u32 pm_api_ret[4] = {0, 0, 0, 0};

        int ret;
        int i = 0;

        strcpy(debugfs_buf, "");

        if (*off != 0 || len <= 1 || len > PAGE_SIZE - 1)
                return -EINVAL;

        kern_buff = memdup_user_nul(ptr, len);
        if (IS_ERR(kern_buff))
                return PTR_ERR(kern_buff);
        tmp_buff = kern_buff;

        /* Read the API name from a user request */
        pm_api_req = strsep(&kern_buff, " ");

        ret = get_pm_api_id(pm_api_req, &pm_id);
        if (ret < 0)
                goto err;

        /* Read node_id and arguments from the PM-API request */
        pm_api_req = strsep(&kern_buff, " ");
        while ((i < ARRAY_SIZE(pm_api_arg)) && pm_api_req) {
                pm_api_arg[i++] = zynqmp_pm_argument_value(pm_api_req);
                pm_api_req = strsep(&kern_buff, " ");
        }

        ret = process_api_request(pm_id, pm_api_arg, pm_api_ret);

err:
        kfree(tmp_buff);
        if (ret)
                return ret;

        return len;
}

/**
 * zynqmp_pm_debugfs_api_read() - debugfs read function
 * @file:       User file
 * @ptr:        Requested pm_api_version string
 * @len:        Length of the userspace buffer
 * @off:        Offset within the file
 *
 * Return: Length of the version string on success
 *         else error code
 */
static ssize_t zynqmp_pm_debugfs_api_read(struct file *file, char __user *ptr,
                                          size_t len, loff_t *off)
{
        return simple_read_from_buffer(ptr, len, off, debugfs_buf,
                                       strlen(debugfs_buf));
}

/* Setup debugfs fops */
static const struct file_operations fops_zynqmp_pm_dbgfs = {
        .owner = THIS_MODULE,
        .write = zynqmp_pm_debugfs_api_write,
        .read = zynqmp_pm_debugfs_api_read,
};

/**
 * zynqmp_pm_api_debugfs_init - Initialize debugfs interface
 *
 * Return:      None
 */
void zynqmp_pm_api_debugfs_init(void)
{
        /* Initialize debugfs interface */
        firmware_debugfs_root = debugfs_create_dir("zynqmp-firmware", NULL);
        debugfs_create_file("pm", 0660, firmware_debugfs_root, NULL,
                            &fops_zynqmp_pm_dbgfs);
}

/**
 * zynqmp_pm_api_debugfs_exit - Remove debugfs interface
 *
 * Return:      None
 */
void zynqmp_pm_api_debugfs_exit(void)
{
        debugfs_remove_recursive(firmware_debugfs_root);
}