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                 if (rproc->state == RPROC_RUNNING)
  36                         return -EBUSY;
  37
  38                 ret = rproc_boot(rproc);
  39         } else if (!strncmp(cmd, "stop", len)) {
  40                 if (rproc->state != RPROC_RUNNING)
  41                         return -EINVAL;
  42
  43                 rproc_shutdown(rproc);
  44         } else {
  45                 dev_err(&rproc->dev, "Unrecognized option\n");
  46                 ret = -EINVAL;
  47         }
  48
  49         return ret ? ret : len;
  50 }
  51
  52 static long rproc_device_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
  53 {
  54         struct rproc *rproc = container_of(filp->f_inode->i_cdev, struct rproc, cdev);
  55         void __user *argp = (void __user *)arg;
  56         s32 param;
  57
  58         switch (ioctl) {
  59         case RPROC_SET_SHUTDOWN_ON_RELEASE:
  60                 if (copy_from_user(&param, argp, sizeof(s32)))
  61                         return -EFAULT;
  62
  63                 rproc->cdev_put_on_release = !!param;
  64                 break;
  65         case RPROC_GET_SHUTDOWN_ON_RELEASE:
  66                 param = (s32)rproc->cdev_put_on_release;
  67                 if (copy_to_user(argp, &param, sizeof(s32)))
  68                         return -EFAULT;
  69
  70                 break;
  71         default:
  72                 dev_err(&rproc->dev, "Unsupported ioctl\n");
  73                 return -EINVAL;
  74         }
  75
  76         return 0;
  77 }
  78
  79 static int rproc_cdev_release(struct inode *inode, struct file *filp)
  80 {
  81         struct rproc *rproc = container_of(inode->i_cdev, struct rproc, cdev);
  82
  83         if (rproc->cdev_put_on_release && rproc->state == RPROC_RUNNING)
  84                 rproc_shutdown(rproc);
  85
  86         return 0;
  87 }
  88
  89 static const struct file_operations rproc_fops = {
  90         .write = rproc_cdev_write,
  91         .unlocked_ioctl = rproc_device_ioctl,
  92         .compat_ioctl = compat_ptr_ioctl,
  93         .release = rproc_cdev_release,
  94 };
  95
  96 int rproc_char_device_add(struct rproc *rproc)
  97 {
  98         int ret;
  99
 100         cdev_init(&rproc->cdev, &rproc_fops);
 101         rproc->cdev.owner = THIS_MODULE;
 102
 103         rproc->dev.devt = MKDEV(MAJOR(rproc_major), rproc->index);
 104         cdev_set_parent(&rproc->cdev, &rproc->dev.kobj);
 105         ret = cdev_add(&rproc->cdev, rproc->dev.devt, 1);
 106         if (ret < 0)
 107                 dev_err(&rproc->dev, "Failed to add char dev for %s\n", rproc->name);
 108
 109         return ret;
 110 }
 111
 112 void rproc_char_device_remove(struct rproc *rproc)
 113 {
 114         __unregister_chrdev(MAJOR(rproc->dev.devt), rproc->index, 1, "remoteproc");
 115 }
 116
 117 void __init rproc_init_cdev(void)
 118 {
 119         int ret;
 120
 121         ret = alloc_chrdev_region(&rproc_major, 0, NUM_RPROC_DEVICES, "remoteproc");
 122         if (ret < 0)
 123                 pr_err("Failed to alloc rproc_cdev region, err %d\n", ret);
 124 }