remoteproc_cdev.c
// 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(¶m, 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, ¶m, 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);
}