// SPDX-License-Identifier: GPL-2.0-only
/*
 * Character device interface driver for Remoteproc framework.
 *
 * Copyright (c) 2020, The Linux Foundation. All rights reserved.
 */

#include <linux/cdev.h>
#include <linux/compat.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/remoteproc.h>
#include <linux/uaccess.h>
#include <uapi/linux/remoteproc_cdev.h>

#include "remoteproc_internal.h"

#define NUM_RPROC_DEVICES       64
static dev_t rproc_major;

static ssize_t rproc_cdev_write(struct file *filp, const char __user *buf, size_t len, loff_t *pos)
{
        struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, cdev);
        int ret = 0;
        char cmd[10];

        if (!len || len > sizeof(cmd))
                return -EINVAL;

        ret = copy_from_user(cmd, buf, len);
        if (ret)
                return -EFAULT;

        if (!strncmp(cmd, "start", len)) {
                ret = rproc_boot(rproc);
        } else if (!strncmp(cmd, "stop", len)) {
                ret = rproc_shutdown(rproc);
        } else if (!strncmp(cmd, "detach", len)) {
                ret = rproc_detach(rproc);
        } else {
                dev_err(&rproc->dev, "Unrecognized option\n");
                ret = -EINVAL;
        }

        return ret ? ret : len;
}

static long rproc_device_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
{
        struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, cdev);
        void __user *argp = (void __user *)arg;
        s32 param;

        switch (ioctl) {
        case RPROC_SET_SHUTDOWN_ON_RELEASE:
                if (copy_from_user(&param, argp, sizeof(s32)))
                        return -EFAULT;

                rproc->cdev_put_on_release = !!param;
                break;
        case RPROC_GET_SHUTDOWN_ON_RELEASE:
                param = (s32)rproc->cdev_put_on_release;
                if (copy_to_user(argp, &param, sizeof(s32)))
                        return -EFAULT;

                break;
        default:
                dev_err(&rproc->dev, "Unsupported ioctl\n");
                return -EINVAL;
        }

        return 0;
}

static int rproc_cdev_release(struct inode *inode, struct file *filp)
{
        struct rproc *rproc = container_of(inode->i_cdev, struct rproc, cdev);
        int ret = 0;

        if (!rproc->cdev_put_on_release)
                return 0;

        if (rproc->state == RPROC_RUNNING)
                rproc_shutdown(rproc);
        else if (rproc->state == RPROC_ATTACHED)
                ret = rproc_detach(rproc);

        return ret;
}

static const struct file_operations rproc_fops = {
        .write = rproc_cdev_write,
        .unlocked_ioctl = rproc_device_ioctl,
        .compat_ioctl = compat_ptr_ioctl,
        .release = rproc_cdev_release,
};

int rproc_char_device_add(struct rproc *rproc)
{
        int ret;

        cdev_init(&rproc->cdev, &rproc_fops);
        rproc->cdev.owner = THIS_MODULE;

        rproc->dev.devt = MKDEV(MAJOR(rproc_major), rproc->index);
        cdev_set_parent(&rproc->cdev, &rproc->dev.kobj);
        ret = cdev_add(&rproc->cdev, rproc->dev.devt, 1);
        if (ret < 0)
                dev_err(&rproc->dev, "Failed to add char dev for %s\n", rproc->name);

        return ret;
}

void rproc_char_device_remove(struct rproc *rproc)
{
        cdev_del(&rproc->cdev);
}

void __init rproc_init_cdev(void)
{
        int ret;

        ret = alloc_chrdev_region(&rproc_major, 0, NUM_RPROC_DEVICES, "remoteproc");
        if (ret < 0)
                pr_err("Failed to alloc rproc_cdev region, err %d\n", ret);
}