drivers/media/usb/uvc/uvc_debugfs.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      uvc_debugfs.c --  USB Video Class driver - Debugging support
   4  *
   5  *      Copyright (C) 2011
   6  *          Laurent Pinchart ([email protected])
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/debugfs.h>
  11 #include <linux/slab.h>
  12 #include <linux/usb.h>
  13
  14 #include "uvcvideo.h"
  15
  16 /* -----------------------------------------------------------------------------
  17  * Statistics
  18  */
  19
  20 #define UVC_DEBUGFS_BUF_SIZE    1024
  21
  22 struct uvc_debugfs_buffer {
  23         size_t count;
  24         char data[UVC_DEBUGFS_BUF_SIZE];
  25 };
  26
  27 static int uvc_debugfs_stats_open(struct inode *inode, struct file *file)
  28 {
  29         struct uvc_streaming *stream = inode->i_private;
  30         struct uvc_debugfs_buffer *buf;
  31
  32         buf = kmalloc(sizeof(*buf), GFP_KERNEL);
  33         if (buf == NULL)
  34                 return -ENOMEM;
  35
  36         buf->count = uvc_video_stats_dump(stream, buf->data, sizeof(buf->data));
  37
  38         file->private_data = buf;
  39         return 0;
  40 }
  41
  42 static ssize_t uvc_debugfs_stats_read(struct file *file, char __user *user_buf,
  43                                       size_t nbytes, loff_t *ppos)
  44 {
  45         struct uvc_debugfs_buffer *buf = file->private_data;
  46
  47         return simple_read_from_buffer(user_buf, nbytes, ppos, buf->data,
  48                                        buf->count);
  49 }
  50
  51 static int uvc_debugfs_stats_release(struct inode *inode, struct file *file)
  52 {
  53         kfree(file->private_data);
  54         file->private_data = NULL;
  55
  56         return 0;
  57 }
  58
  59 static const struct file_operations uvc_debugfs_stats_fops = {
  60         .owner = THIS_MODULE,
  61         .open = uvc_debugfs_stats_open,
  62         .read = uvc_debugfs_stats_read,
  63         .release = uvc_debugfs_stats_release,
  64 };
  65
  66 /* -----------------------------------------------------------------------------
  67  * Global and stream initialization/cleanup
  68  */
  69
  70 static struct dentry *uvc_debugfs_root_dir;
  71
  72 void uvc_debugfs_init_stream(struct uvc_streaming *stream)
  73 {
  74         struct usb_device *udev = stream->dev->udev;
  75         char dir_name[33];
  76
  77         if (uvc_debugfs_root_dir == NULL)
  78                 return;
  79
  80         snprintf(dir_name, sizeof(dir_name), "%u-%u-%u", udev->bus->busnum,
  81                  udev->devnum, stream->intfnum);
  82
  83         stream->debugfs_dir = debugfs_create_dir(dir_name,
  84                                                  uvc_debugfs_root_dir);
  85
  86         debugfs_create_file("stats", 0444, stream->debugfs_dir, stream,
  87                             &uvc_debugfs_stats_fops);
  88 }
  89
  90 void uvc_debugfs_cleanup_stream(struct uvc_streaming *stream)
  91 {
  92         debugfs_remove_recursive(stream->debugfs_dir);
  93         stream->debugfs_dir = NULL;
  94 }
  95
  96 void uvc_debugfs_init(void)
  97 {
  98         uvc_debugfs_root_dir = debugfs_create_dir("uvcvideo", usb_debug_root);
  99 }
 100
 101 void uvc_debugfs_cleanup(void)
 102 {
 103         debugfs_remove_recursive(uvc_debugfs_root_dir);
 104 }