drivers/media/usb/uvc/uvc_debugfs.c

   1 /*
   2  *      uvc_debugfs.c --  USB Video Class driver - Debugging support
   3  *
   4  *      Copyright (C) 2011
   5  *          Laurent Pinchart (laurent.pinchart@ideasonboard.com)
   6  *
   7  *      This program is free software; you can redistribute it and/or modify
   8  *      it under the terms of the GNU General Public License as published by
   9  *      the Free Software Foundation; either version 2 of the License, or
  10  *      (at your option) any later version.
  11  *
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/debugfs.h>
  16 #include <linux/slab.h>
  17 #include <linux/usb.h>
  18
  19 #include "uvcvideo.h"
  20
  21 /* -----------------------------------------------------------------------------
  22  * Statistics
  23  */
  24
  25 #define UVC_DEBUGFS_BUF_SIZE    1024
  26
  27 struct uvc_debugfs_buffer {
  28         size_t count;
  29         char data[UVC_DEBUGFS_BUF_SIZE];
  30 };
  31
  32 static int uvc_debugfs_stats_open(struct inode *inode, struct file *file)
  33 {
  34         struct uvc_streaming *stream = inode->i_private;
  35         struct uvc_debugfs_buffer *buf;
  36
  37         buf = kmalloc(sizeof(*buf), GFP_KERNEL);
  38         if (buf == NULL)
  39                 return -ENOMEM;
  40
  41         buf->count = uvc_video_stats_dump(stream, buf->data, sizeof(buf->data));
  42
  43         file->private_data = buf;
  44         return 0;
  45 }
  46
  47 static ssize_t uvc_debugfs_stats_read(struct file *file, char __user *user_buf,
  48                                       size_t nbytes, loff_t *ppos)
  49 {
  50         struct uvc_debugfs_buffer *buf = file->private_data;
  51
  52         return simple_read_from_buffer(user_buf, nbytes, ppos, buf->data,
  53                                        buf->count);
  54 }
  55
  56 static int uvc_debugfs_stats_release(struct inode *inode, struct file *file)
  57 {
  58         kfree(file->private_data);
  59         file->private_data = NULL;
  60
  61         return 0;
  62 }
  63
  64 static const struct file_operations uvc_debugfs_stats_fops = {
  65         .owner = THIS_MODULE,
  66         .open = uvc_debugfs_stats_open,
  67         .llseek = no_llseek,
  68         .read = uvc_debugfs_stats_read,
  69         .release = uvc_debugfs_stats_release,
  70 };
  71
  72 /* -----------------------------------------------------------------------------
  73  * Global and stream initialization/cleanup
  74  */
  75
  76 static struct dentry *uvc_debugfs_root_dir;
  77
  78 int uvc_debugfs_init_stream(struct uvc_streaming *stream)
  79 {
  80         struct usb_device *udev = stream->dev->udev;
  81         struct dentry *dent;
  82         char dir_name[32];
  83
  84         if (uvc_debugfs_root_dir == NULL)
  85                 return -ENODEV;
  86
  87         sprintf(dir_name, "%u-%u", udev->bus->busnum, udev->devnum);
  88
  89         dent = debugfs_create_dir(dir_name, uvc_debugfs_root_dir);
  90         if (IS_ERR_OR_NULL(dent)) {
  91                 uvc_printk(KERN_INFO, "Unable to create debugfs %s "
  92                            "directory.\n", dir_name);
  93                 return -ENODEV;
  94         }
  95
  96         stream->debugfs_dir = dent;
  97
  98         dent = debugfs_create_file("stats", 0444, stream->debugfs_dir,
  99                                    stream, &uvc_debugfs_stats_fops);
 100         if (IS_ERR_OR_NULL(dent)) {
 101                 uvc_printk(KERN_INFO, "Unable to create debugfs stats file.\n");
 102                 uvc_debugfs_cleanup_stream(stream);
 103                 return -ENODEV;
 104         }
 105
 106         return 0;
 107 }
 108
 109 void uvc_debugfs_cleanup_stream(struct uvc_streaming *stream)
 110 {
 111         if (stream->debugfs_dir == NULL)
 112                 return;
 113
 114         debugfs_remove_recursive(stream->debugfs_dir);
 115         stream->debugfs_dir = NULL;
 116 }
 117
 118 int uvc_debugfs_init(void)
 119 {
 120         struct dentry *dir;
 121
 122         dir = debugfs_create_dir("uvcvideo", usb_debug_root);
 123         if (IS_ERR_OR_NULL(dir)) {
 124                 uvc_printk(KERN_INFO, "Unable to create debugfs directory\n");
 125                 return -ENODATA;
 126         }
 127
 128         uvc_debugfs_root_dir = dir;
 129         return 0;
 130 }
 131
 132 void uvc_debugfs_cleanup(void)
 133 {
 134         if (uvc_debugfs_root_dir != NULL)
 135                 debugfs_remove_recursive(uvc_debugfs_root_dir);
 136 }