| 1 | |
| 2 | * file.c - part of debugfs, a tiny little debug file system
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| 3 | *
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| 4 | * Copyright (C) 2004 Greg Kroah-Hartman <[email protected]>
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| 5 | * Copyright (C) 2004 IBM Inc.
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| 6 | *
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| 7 | * This program is free software; you can redistribute it and/or
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| 8 | * modify it under the terms of the GNU General Public License version
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| 9 | * 2 as published by the Free Software Foundation.
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| 10 | *
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| 11 | * debugfs is for people to use instead of /proc or /sys.
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| 12 | * See Documentation/DocBook/kernel-api for more details.
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| 13 | *
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| 14 |
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| 15 |
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| 16 | #include <linux/module.h>
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| 17 | #include <linux/fs.h>
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| 18 | #include <linux/pagemap.h>
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| 19 | #include <linux/namei.h>
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| 20 | #include <linux/debugfs.h>
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| 21 |
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| 22 | static ssize_t default_read_file(struct file *file, char __user *buf,
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| 23 | size_t count, loff_t *ppos)
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| 24 | {
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| 25 | return 0;
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| 26 | }
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| 27 |
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| 28 | static ssize_t default_write_file(struct file *file, const char __user *buf,
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| 29 | size_t count, loff_t *ppos)
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| 30 | {
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| 31 | return count;
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| 32 | }
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| 33 |
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| 34 | static int default_open(struct inode *inode, struct file *file)
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| 35 | {
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| 36 | if (inode->i_private)
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| 37 | file->private_data = inode->i_private;
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| 38 |
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| 39 | return 0;
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| 40 | }
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| 41 |
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| 42 | const struct file_operations debugfs_file_operations = {
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| 43 | .read = default_read_file,
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| 44 | .write = default_write_file,
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| 45 | .open = default_open,
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| 46 | };
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| 47 |
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| 48 | static void *debugfs_follow_link(struct dentry *dentry, struct nameidata *nd)
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| 49 | {
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| 50 | nd_set_link(nd, dentry->d_inode->i_private);
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| 51 | return NULL;
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| 52 | }
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| 53 |
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| 54 | const struct inode_operations debugfs_link_operations = {
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| 55 | .readlink = generic_readlink,
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| 56 | .follow_link = debugfs_follow_link,
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| 57 | };
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| 58 |
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| 59 | static void debugfs_u8_set(void *data, u64 val)
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| 60 | {
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| 61 | *(u8 *)data = val;
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| 62 | }
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| 63 | static u64 debugfs_u8_get(void *data)
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| 64 | {
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| 65 | return *(u8 *)data;
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| 66 | }
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| 67 | DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
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| 68 |
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| 69 | |
| 70 | * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
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| 71 | * @name: a pointer to a string containing the name of the file to create.
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| 72 | * @mode: the permission that the file should have
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| 73 | * @parent: a pointer to the parent dentry for this file. This should be a
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| 74 | * directory dentry if set. If this parameter is %NULL, then the
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| 75 | * file will be created in the root of the debugfs filesystem.
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| 76 | * @value: a pointer to the variable that the file should read to and write
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| 77 | * from.
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| 78 | *
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| 79 | * This function creates a file in debugfs with the given name that
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| 80 | * contains the value of the variable @value. If the @mode variable is so
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| 81 | * set, it can be read from, and written to.
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| 82 | *
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| 83 | * This function will return a pointer to a dentry if it succeeds. This
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| 84 | * pointer must be passed to the debugfs_remove() function when the file is
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| 85 | * to be removed (no automatic cleanup happens if your module is unloaded,
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| 86 | * you are responsible here.) If an error occurs, %NULL will be returned.
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| 87 | *
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| 88 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be
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| 89 | * returned. It is not wise to check for this value, but rather, check for
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| 90 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
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| 91 | * code.
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| 92 |
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| 93 | struct dentry *debugfs_create_u8(const char *name, mode_t mode,
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| 94 | struct dentry *parent, u8 *value)
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| 95 | {
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| 96 | return debugfs_create_file(name, mode, parent, value, &fops_u8);
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| 97 | }
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| 98 | EXPORT_SYMBOL_GPL(debugfs_create_u8);
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| 99 |
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| 100 | static void debugfs_u16_set(void *data, u64 val)
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| 101 | {
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| 102 | *(u16 *)data = val;
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| 103 | }
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| 104 | static u64 debugfs_u16_get(void *data)
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| 105 | {
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| 106 | return *(u16 *)data;
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| 107 | }
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| 108 | DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
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| 109 |
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| 110 | |
| 111 | * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
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| 112 | * @name: a pointer to a string containing the name of the file to create.
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| 113 | * @mode: the permission that the file should have
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| 114 | * @parent: a pointer to the parent dentry for this file. This should be a
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| 115 | * directory dentry if set. If this parameter is %NULL, then the
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| 116 | * file will be created in the root of the debugfs filesystem.
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| 117 | * @value: a pointer to the variable that the file should read to and write
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| 118 | * from.
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| 119 | *
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| 120 | * This function creates a file in debugfs with the given name that
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| 121 | * contains the value of the variable @value. If the @mode variable is so
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| 122 | * set, it can be read from, and written to.
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| 123 | *
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| 124 | * This function will return a pointer to a dentry if it succeeds. This
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| 125 | * pointer must be passed to the debugfs_remove() function when the file is
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| 126 | * to be removed (no automatic cleanup happens if your module is unloaded,
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| 127 | * you are responsible here.) If an error occurs, %NULL will be returned.
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| 128 | *
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| 129 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be
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| 130 | * returned. It is not wise to check for this value, but rather, check for
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| 131 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
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| 132 | * code.
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| 133 |
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| 134 | struct dentry *debugfs_create_u16(const char *name, mode_t mode,
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| 135 | struct dentry *parent, u16 *value)
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| 136 | {
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| 137 | return debugfs_create_file(name, mode, parent, value, &fops_u16);
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| 138 | }
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| 139 | EXPORT_SYMBOL_GPL(debugfs_create_u16);
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| 140 |
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| 141 | static void debugfs_u32_set(void *data, u64 val)
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| 142 | {
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| 143 | *(u32 *)data = val;
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| 144 | }
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| 145 | static u64 debugfs_u32_get(void *data)
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| 146 | {
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| 147 | return *(u32 *)data;
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| 148 | }
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| 149 | DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
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| 150 |
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| 151 | |
| 152 | * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
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| 153 | * @name: a pointer to a string containing the name of the file to create.
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| 154 | * @mode: the permission that the file should have
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| 155 | * @parent: a pointer to the parent dentry for this file. This should be a
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| 156 | * directory dentry if set. If this parameter is %NULL, then the
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| 157 | * file will be created in the root of the debugfs filesystem.
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| 158 | * @value: a pointer to the variable that the file should read to and write
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| 159 | * from.
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| 160 | *
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| 161 | * This function creates a file in debugfs with the given name that
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| 162 | * contains the value of the variable @value. If the @mode variable is so
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| 163 | * set, it can be read from, and written to.
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| 164 | *
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| 165 | * This function will return a pointer to a dentry if it succeeds. This
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| 166 | * pointer must be passed to the debugfs_remove() function when the file is
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| 167 | * to be removed (no automatic cleanup happens if your module is unloaded,
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| 168 | * you are responsible here.) If an error occurs, %NULL will be returned.
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| 169 | *
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| 170 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be
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| 171 | * returned. It is not wise to check for this value, but rather, check for
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| 172 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
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| 173 | * code.
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| 174 |
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| 175 | struct dentry *debugfs_create_u32(const char *name, mode_t mode,
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| 176 | struct dentry *parent, u32 *value)
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| 177 | {
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| 178 | return debugfs_create_file(name, mode, parent, value, &fops_u32);
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| 179 | }
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| 180 | EXPORT_SYMBOL_GPL(debugfs_create_u32);
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| 181 |
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| 182 | static ssize_t read_file_bool(struct file *file, char __user *user_buf,
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| 183 | size_t count, loff_t *ppos)
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| 184 | {
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| 185 | char buf[3];
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| 186 | u32 *val = file->private_data;
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| 187 |
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| 188 | if (*val)
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| 189 | buf[0] = 'Y';
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| 190 | else
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| 191 | buf[0] = 'N';
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| 192 | buf[1] = '\n';
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| 193 | buf[2] = 0x00;
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| 194 | return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
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| 195 | }
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| 196 |
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| 197 | static ssize_t write_file_bool(struct file *file, const char __user *user_buf,
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| 198 | size_t count, loff_t *ppos)
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| 199 | {
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| 200 | char buf[32];
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| 201 | int buf_size;
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| 202 | u32 *val = file->private_data;
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| 203 |
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| 204 | buf_size = min(count, (sizeof(buf)-1));
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| 205 | if (copy_from_user(buf, user_buf, buf_size))
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| 206 | return -EFAULT;
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| 207 |
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| 208 | switch (buf[0]) {
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| 209 | case 'y':
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| 210 | case 'Y':
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| 211 | case '1':
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| 212 | *val = 1;
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| 213 | break;
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| 214 | case 'n':
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| 215 | case 'N':
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| 216 | case '0':
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| 217 | *val = 0;
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| 218 | break;
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| 219 | }
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| 220 |
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| 221 | return count;
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| 222 | }
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| 223 |
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| 224 | static const struct file_operations fops_bool = {
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| 225 | .read = read_file_bool,
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| 226 | .write = write_file_bool,
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| 227 | .open = default_open,
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| 228 | };
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| 229 |
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| 230 | |
| 231 | * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
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| 232 | * @name: a pointer to a string containing the name of the file to create.
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| 233 | * @mode: the permission that the file should have
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| 234 | * @parent: a pointer to the parent dentry for this file. This should be a
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| 235 | * directory dentry if set. If this parameter is %NULL, then the
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| 236 | * file will be created in the root of the debugfs filesystem.
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| 237 | * @value: a pointer to the variable that the file should read to and write
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| 238 | * from.
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| 239 | *
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| 240 | * This function creates a file in debugfs with the given name that
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| 241 | * contains the value of the variable @value. If the @mode variable is so
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| 242 | * set, it can be read from, and written to.
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| 243 | *
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| 244 | * This function will return a pointer to a dentry if it succeeds. This
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| 245 | * pointer must be passed to the debugfs_remove() function when the file is
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| 246 | * to be removed (no automatic cleanup happens if your module is unloaded,
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| 247 | * you are responsible here.) If an error occurs, %NULL will be returned.
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| 248 | *
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| 249 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be
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| 250 | * returned. It is not wise to check for this value, but rather, check for
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| 251 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
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| 252 | * code.
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| 253 |
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| 254 | struct dentry *debugfs_create_bool(const char *name, mode_t mode,
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| 255 | struct dentry *parent, u32 *value)
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| 256 | {
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| 257 | return debugfs_create_file(name, mode, parent, value, &fops_bool);
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| 258 | }
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| 259 | EXPORT_SYMBOL_GPL(debugfs_create_bool);
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| 260 |
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| 261 | static ssize_t read_file_blob(struct file *file, char __user *user_buf,
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| 262 | size_t count, loff_t *ppos)
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| 263 | {
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| 264 | struct debugfs_blob_wrapper *blob = file->private_data;
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| 265 | return simple_read_from_buffer(user_buf, count, ppos, blob->data,
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| 266 | blob->size);
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| 267 | }
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| 268 |
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| 269 | static const struct file_operations fops_blob = {
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| 270 | .read = read_file_blob,
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| 271 | .open = default_open,
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| 272 | };
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| 273 |
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| 274 | |
| 275 | * debugfs_create_blob - create a debugfs file that is used to read and write a binary blob
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| 276 | * @name: a pointer to a string containing the name of the file to create.
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| 277 | * @mode: the permission that the file should have
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| 278 | * @parent: a pointer to the parent dentry for this file. This should be a
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| 279 | * directory dentry if set. If this parameter is %NULL, then the
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| 280 | * file will be created in the root of the debugfs filesystem.
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| 281 | * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
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| 282 | * to the blob data and the size of the data.
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| 283 | *
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| 284 | * This function creates a file in debugfs with the given name that exports
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| 285 | * @blob->data as a binary blob. If the @mode variable is so set it can be
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| 286 | * read from. Writing is not supported.
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| 287 | *
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| 288 | * This function will return a pointer to a dentry if it succeeds. This
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| 289 | * pointer must be passed to the debugfs_remove() function when the file is
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| 290 | * to be removed (no automatic cleanup happens if your module is unloaded,
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| 291 | * you are responsible here.) If an error occurs, %NULL will be returned.
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| 292 | *
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| 293 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be
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| 294 | * returned. It is not wise to check for this value, but rather, check for
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| 295 | * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
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| 296 | * code.
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| 297 |
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| 298 | struct dentry *debugfs_create_blob(const char *name, mode_t mode,
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| 299 | struct dentry *parent,
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| 300 | struct debugfs_blob_wrapper *blob)
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| 301 | {
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| 302 | return debugfs_create_file(name, mode, parent, blob, &fops_blob);
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| 303 | }
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| 304 | EXPORT_SYMBOL_GPL(debugfs_create_blob);
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