drivers/remoteproc/remoteproc_cdev.c

   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
  19 static dev_t rproc_major;
  20
  21 static 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
  48 static 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
  75 static 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
  91 static 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
  98 int 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
 114 void rproc_char_device_remove(struct rproc *rproc)
 115 {
 116         cdev_del(&rproc->cdev);
 117 }
 118
 119 void __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 }