loopdev: fix a deadlock
[linux-2.6.git] / drivers / base / regmap / regmap-debugfs.c
1 /*
2  * Register map access API - debugfs
3  *
4  * Copyright 2011 Wolfson Microelectronics plc
5  *
6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12
13 #include <linux/slab.h>
14 #include <linux/mutex.h>
15 #include <linux/debugfs.h>
16 #include <linux/uaccess.h>
17 #include <linux/device.h>
18
19 #include "internal.h"
20
21 static struct dentry *regmap_debugfs_root;
22
23 /* Calculate the length of a fixed format  */
24 static size_t regmap_calc_reg_len(int max_val, char *buf, size_t buf_size)
25 {
26         snprintf(buf, buf_size, "%x", max_val);
27         return strlen(buf);
28 }
29
30 static ssize_t regmap_name_read_file(struct file *file,
31                                      char __user *user_buf, size_t count,
32                                      loff_t *ppos)
33 {
34         struct regmap *map = file->private_data;
35         int ret;
36         char *buf;
37
38         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
39         if (!buf)
40                 return -ENOMEM;
41
42         ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
43         if (ret < 0) {
44                 kfree(buf);
45                 return ret;
46         }
47
48         ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
49         kfree(buf);
50         return ret;
51 }
52
53 static const struct file_operations regmap_name_fops = {
54         .open = simple_open,
55         .read = regmap_name_read_file,
56         .llseek = default_llseek,
57 };
58
59 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
60                                     size_t count, loff_t *ppos)
61 {
62         int reg_len, val_len, tot_len;
63         size_t buf_pos = 0;
64         loff_t p = 0;
65         ssize_t ret;
66         int i;
67         struct regmap *map = file->private_data;
68         char *buf;
69         unsigned int val;
70
71         if (*ppos < 0 || !count)
72                 return -EINVAL;
73
74         buf = kmalloc(count, GFP_KERNEL);
75         if (!buf)
76                 return -ENOMEM;
77
78         /* Calculate the length of a fixed format  */
79         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
80         val_len = 2 * map->format.val_bytes;
81         tot_len = reg_len + val_len + 3;      /* : \n */
82
83         for (i = 0; i < map->max_register + 1; i++) {
84                 if (!regmap_readable(map, i))
85                         continue;
86
87                 if (regmap_precious(map, i))
88                         continue;
89
90                 /* If we're in the region the user is trying to read */
91                 if (p >= *ppos) {
92                         /* ...but not beyond it */
93                         if (buf_pos + 1 + tot_len >= count)
94                                 break;
95
96                         /* Format the register */
97                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
98                                  reg_len, i);
99                         buf_pos += reg_len + 2;
100
101                         /* Format the value, write all X if we can't read */
102                         ret = regmap_read(map, i, &val);
103                         if (ret == 0)
104                                 snprintf(buf + buf_pos, count - buf_pos,
105                                          "%.*x", val_len, val);
106                         else
107                                 memset(buf + buf_pos, 'X', val_len);
108                         buf_pos += 2 * map->format.val_bytes;
109
110                         buf[buf_pos++] = '\n';
111                 }
112                 p += tot_len;
113         }
114
115         ret = buf_pos;
116
117         if (copy_to_user(user_buf, buf, buf_pos)) {
118                 ret = -EFAULT;
119                 goto out;
120         }
121
122         *ppos += buf_pos;
123
124 out:
125         kfree(buf);
126         return ret;
127 }
128
129 #undef REGMAP_ALLOW_WRITE_DEBUGFS
130 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
131 /*
132  * This can be dangerous especially when we have clients such as
133  * PMICs, therefore don't provide any real compile time configuration option
134  * for this feature, people who want to use this will need to modify
135  * the source code directly.
136  */
137 static ssize_t regmap_map_write_file(struct file *file,
138                                      const char __user *user_buf,
139                                      size_t count, loff_t *ppos)
140 {
141         char buf[32];
142         size_t buf_size;
143         char *start = buf;
144         unsigned long reg, value;
145         struct regmap *map = file->private_data;
146
147         buf_size = min(count, (sizeof(buf)-1));
148         if (copy_from_user(buf, user_buf, buf_size))
149                 return -EFAULT;
150         buf[buf_size] = 0;
151
152         while (*start == ' ')
153                 start++;
154         reg = simple_strtoul(start, &start, 16);
155         while (*start == ' ')
156                 start++;
157         if (strict_strtoul(start, 16, &value))
158                 return -EINVAL;
159
160         /* Userspace has been fiddling around behind the kernel's back */
161         add_taint(TAINT_USER);
162
163         regmap_write(map, reg, value);
164         return buf_size;
165 }
166 #else
167 #define regmap_map_write_file NULL
168 #endif
169
170 static const struct file_operations regmap_map_fops = {
171         .open = simple_open,
172         .read = regmap_map_read_file,
173         .write = regmap_map_write_file,
174         .llseek = default_llseek,
175 };
176
177 static ssize_t regmap_access_read_file(struct file *file,
178                                        char __user *user_buf, size_t count,
179                                        loff_t *ppos)
180 {
181         int reg_len, tot_len;
182         size_t buf_pos = 0;
183         loff_t p = 0;
184         ssize_t ret;
185         int i;
186         struct regmap *map = file->private_data;
187         char *buf;
188
189         if (*ppos < 0 || !count)
190                 return -EINVAL;
191
192         buf = kmalloc(count, GFP_KERNEL);
193         if (!buf)
194                 return -ENOMEM;
195
196         /* Calculate the length of a fixed format  */
197         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
198         tot_len = reg_len + 10; /* ': R W V P\n' */
199
200         for (i = 0; i < map->max_register + 1; i++) {
201                 /* Ignore registers which are neither readable nor writable */
202                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
203                         continue;
204
205                 /* If we're in the region the user is trying to read */
206                 if (p >= *ppos) {
207                         /* ...but not beyond it */
208                         if (buf_pos >= count - 1 - tot_len)
209                                 break;
210
211                         /* Format the register */
212                         snprintf(buf + buf_pos, count - buf_pos,
213                                  "%.*x: %c %c %c %c\n",
214                                  reg_len, i,
215                                  regmap_readable(map, i) ? 'y' : 'n',
216                                  regmap_writeable(map, i) ? 'y' : 'n',
217                                  regmap_volatile(map, i) ? 'y' : 'n',
218                                  regmap_precious(map, i) ? 'y' : 'n');
219
220                         buf_pos += tot_len;
221                 }
222                 p += tot_len;
223         }
224
225         ret = buf_pos;
226
227         if (copy_to_user(user_buf, buf, buf_pos)) {
228                 ret = -EFAULT;
229                 goto out;
230         }
231
232         *ppos += buf_pos;
233
234 out:
235         kfree(buf);
236         return ret;
237 }
238
239 static const struct file_operations regmap_access_fops = {
240         .open = simple_open,
241         .read = regmap_access_read_file,
242         .llseek = default_llseek,
243 };
244
245 void regmap_debugfs_init(struct regmap *map)
246 {
247         map->debugfs = debugfs_create_dir(dev_name(map->dev),
248                                           regmap_debugfs_root);
249         if (!map->debugfs) {
250                 dev_warn(map->dev, "Failed to create debugfs directory\n");
251                 return;
252         }
253
254         debugfs_create_file("name", 0400, map->debugfs,
255                             map, &regmap_name_fops);
256
257         if (map->max_register) {
258                 debugfs_create_file("registers", 0400, map->debugfs,
259                                     map, &regmap_map_fops);
260                 debugfs_create_file("access", 0400, map->debugfs,
261                                     map, &regmap_access_fops);
262         }
263
264         if (map->cache_type) {
265                 debugfs_create_bool("cache_only", 0400, map->debugfs,
266                                     &map->cache_only);
267                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
268                                     &map->cache_dirty);
269                 debugfs_create_bool("cache_bypass", 0400, map->debugfs,
270                                     &map->cache_bypass);
271         }
272 }
273
274 void regmap_debugfs_exit(struct regmap *map)
275 {
276         debugfs_remove_recursive(map->debugfs);
277 }
278
279 void regmap_debugfs_initcall(void)
280 {
281         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
282         if (!regmap_debugfs_root) {
283                 pr_warn("regmap: Failed to create debugfs root\n");
284                 return;
285         }
286 }