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 (laurent.pinchart@ideasonboard.com) 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 } 105