1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Character device interface driver for Remoteproc framework.
  4 *
  5 * Copyright (c) 2020, The Linux Foundation. All rights reserved.
  6 */
  7
  8#include <linux/cdev.h>
  9#include <linux/compat.h>
 10#include <linux/fs.h>
 11#include <linux/module.h>
 12#include <linux/remoteproc.h>
 13#include <linux/uaccess.h>
 14#include <uapi/linux/remoteproc_cdev.h>
 15
 16#include "remoteproc_internal.h"
 17
 18#define NUM_RPROC_DEVICES	64
 19static dev_t rproc_major;
 20
 21static ssize_t rproc_cdev_write(struct file *filp, const char __user *buf, size_t len, loff_t *pos)
 22{
 23	struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, cdev);
 24	int ret = 0;
 25	char cmd[10];
 26
 27	if (!len || len > sizeof(cmd))
 28		return -EINVAL;
 29
 30	ret = copy_from_user(cmd, buf, len);
 31	if (ret)
 32		return -EFAULT;
 33
 34	if (!strncmp(cmd, "start", len)) {
 35		ret = rproc_boot(rproc);
 36	} else if (!strncmp(cmd, "stop", len)) {
 37		ret = rproc_shutdown(rproc);
 38	} else if (!strncmp(cmd, "detach", len)) {
 39		ret = rproc_detach(rproc);
 40	} else {
 41		dev_err(&rproc->dev, "Unrecognized option\n");
 42		ret = -EINVAL;
 43	}
 44
 45	return ret ? ret : len;
 46}
 47
 48static long rproc_device_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
 49{
 50	struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, cdev);
 51	void __user *argp = (void __user *)arg;
 52	s32 param;
 53
 54	switch (ioctl) {
 55	case RPROC_SET_SHUTDOWN_ON_RELEASE:
 56		if (copy_from_user(&param, argp, sizeof(s32)))
 57			return -EFAULT;
 58
 59		rproc->cdev_put_on_release = !!param;
 60		break;
 61	case RPROC_GET_SHUTDOWN_ON_RELEASE:
 62		param = (s32)rproc->cdev_put_on_release;
 63		if (copy_to_user(argp, &param, sizeof(s32)))
 64			return -EFAULT;
 65
 66		break;
 67	default:
 68		dev_err(&rproc->dev, "Unsupported ioctl\n");
 69		return -EINVAL;
 70	}
 71
 72	return 0;
 73}
 74
 75static int rproc_cdev_release(struct inode *inode, struct file *filp)
 76{
 77	struct rproc *rproc = container_of(inode->i_cdev, struct rproc, cdev);
 78	int ret = 0;
 79
 80	if (!rproc->cdev_put_on_release)
 81		return 0;
 82
 83	if (rproc->state == RPROC_RUNNING)
 84		rproc_shutdown(rproc);
 85	else if (rproc->state == RPROC_ATTACHED)
 86		ret = rproc_detach(rproc);
 87
 88	return ret;
 89}
 90
 91static const struct file_operations rproc_fops = {
 92	.write = rproc_cdev_write,
 93	.unlocked_ioctl = rproc_device_ioctl,
 94	.compat_ioctl = compat_ptr_ioctl,
 95	.release = rproc_cdev_release,
 96};
 97
 98int rproc_char_device_add(struct rproc *rproc)
 99{
100	int ret;
101
102	cdev_init(&rproc->cdev, &rproc_fops);
103	rproc->cdev.owner = THIS_MODULE;
104
105	rproc->dev.devt = MKDEV(MAJOR(rproc_major), rproc->index);
106	cdev_set_parent(&rproc->cdev, &rproc->dev.kobj);
107	ret = cdev_add(&rproc->cdev, rproc->dev.devt, 1);
108	if (ret < 0)
109		dev_err(&rproc->dev, "Failed to add char dev for %s\n", rproc->name);
110
111	return ret;
112}
113
114void rproc_char_device_remove(struct rproc *rproc)
115{
116	cdev_del(&rproc->cdev);
117}
118
119void __init rproc_init_cdev(void)
120{
121	int ret;
122
123	ret = alloc_chrdev_region(&rproc_major, 0, NUM_RPROC_DEVICES, "remoteproc");
124	if (ret < 0)
125		pr_err("Failed to alloc rproc_cdev region, err %d\n", ret);
126}