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_read_debugfs(struct regmap *map, unsigned int from,
60 				   unsigned int to, char __user *user_buf,
61 				   size_t count, loff_t *ppos)
62 {
63 	int reg_len, val_len, tot_len;
64 	size_t buf_pos = 0;
65 	loff_t p = 0;
66 	ssize_t ret;
67 	int i;
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 = from; i <= to; i += map->reg_stride) {
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 >= count - 1 - tot_len)
94 				break;
95 
96 			/* Format the register */
97 			snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
98 				 reg_len, i - from);
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 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
130 				    size_t count, loff_t *ppos)
131 {
132 	struct regmap *map = file->private_data;
133 
134 	return regmap_read_debugfs(map, 0, map->max_register, user_buf,
135 				   count, ppos);
136 }
137 
138 #undef REGMAP_ALLOW_WRITE_DEBUGFS
139 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
140 /*
141  * This can be dangerous especially when we have clients such as
142  * PMICs, therefore don't provide any real compile time configuration option
143  * for this feature, people who want to use this will need to modify
144  * the source code directly.
145  */
146 static ssize_t regmap_map_write_file(struct file *file,
147 				     const char __user *user_buf,
148 				     size_t count, loff_t *ppos)
149 {
150 	char buf[32];
151 	size_t buf_size;
152 	char *start = buf;
153 	unsigned long reg, value;
154 	struct regmap *map = file->private_data;
155 
156 	buf_size = min(count, (sizeof(buf)-1));
157 	if (copy_from_user(buf, user_buf, buf_size))
158 		return -EFAULT;
159 	buf[buf_size] = 0;
160 
161 	while (*start == ' ')
162 		start++;
163 	reg = simple_strtoul(start, &start, 16);
164 	while (*start == ' ')
165 		start++;
166 	if (strict_strtoul(start, 16, &value))
167 		return -EINVAL;
168 
169 	/* Userspace has been fiddling around behind the kernel's back */
170 	add_taint(TAINT_USER);
171 
172 	regmap_write(map, reg, value);
173 	return buf_size;
174 }
175 #else
176 #define regmap_map_write_file NULL
177 #endif
178 
179 static const struct file_operations regmap_map_fops = {
180 	.open = simple_open,
181 	.read = regmap_map_read_file,
182 	.write = regmap_map_write_file,
183 	.llseek = default_llseek,
184 };
185 
186 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
187 				      size_t count, loff_t *ppos)
188 {
189 	struct regmap_range_node *range = file->private_data;
190 	struct regmap *map = range->map;
191 
192 	return regmap_read_debugfs(map, range->range_min, range->range_max,
193 				   user_buf, count, ppos);
194 }
195 
196 static const struct file_operations regmap_range_fops = {
197 	.open = simple_open,
198 	.read = regmap_range_read_file,
199 	.llseek = default_llseek,
200 };
201 
202 static ssize_t regmap_access_read_file(struct file *file,
203 				       char __user *user_buf, size_t count,
204 				       loff_t *ppos)
205 {
206 	int reg_len, tot_len;
207 	size_t buf_pos = 0;
208 	loff_t p = 0;
209 	ssize_t ret;
210 	int i;
211 	struct regmap *map = file->private_data;
212 	char *buf;
213 
214 	if (*ppos < 0 || !count)
215 		return -EINVAL;
216 
217 	buf = kmalloc(count, GFP_KERNEL);
218 	if (!buf)
219 		return -ENOMEM;
220 
221 	/* Calculate the length of a fixed format  */
222 	reg_len = regmap_calc_reg_len(map->max_register, buf, count);
223 	tot_len = reg_len + 10; /* ': R W V P\n' */
224 
225 	for (i = 0; i <= map->max_register; i += map->reg_stride) {
226 		/* Ignore registers which are neither readable nor writable */
227 		if (!regmap_readable(map, i) && !regmap_writeable(map, i))
228 			continue;
229 
230 		/* If we're in the region the user is trying to read */
231 		if (p >= *ppos) {
232 			/* ...but not beyond it */
233 			if (buf_pos >= count - 1 - tot_len)
234 				break;
235 
236 			/* Format the register */
237 			snprintf(buf + buf_pos, count - buf_pos,
238 				 "%.*x: %c %c %c %c\n",
239 				 reg_len, i,
240 				 regmap_readable(map, i) ? 'y' : 'n',
241 				 regmap_writeable(map, i) ? 'y' : 'n',
242 				 regmap_volatile(map, i) ? 'y' : 'n',
243 				 regmap_precious(map, i) ? 'y' : 'n');
244 
245 			buf_pos += tot_len;
246 		}
247 		p += tot_len;
248 	}
249 
250 	ret = buf_pos;
251 
252 	if (copy_to_user(user_buf, buf, buf_pos)) {
253 		ret = -EFAULT;
254 		goto out;
255 	}
256 
257 	*ppos += buf_pos;
258 
259 out:
260 	kfree(buf);
261 	return ret;
262 }
263 
264 static const struct file_operations regmap_access_fops = {
265 	.open = simple_open,
266 	.read = regmap_access_read_file,
267 	.llseek = default_llseek,
268 };
269 
270 void regmap_debugfs_init(struct regmap *map, const char *name)
271 {
272 	struct rb_node *next;
273 	struct regmap_range_node *range_node;
274 
275 	if (name) {
276 		map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
277 					      dev_name(map->dev), name);
278 		name = map->debugfs_name;
279 	} else {
280 		name = dev_name(map->dev);
281 	}
282 
283 	map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
284 	if (!map->debugfs) {
285 		dev_warn(map->dev, "Failed to create debugfs directory\n");
286 		return;
287 	}
288 
289 	debugfs_create_file("name", 0400, map->debugfs,
290 			    map, &regmap_name_fops);
291 
292 	if (map->max_register) {
293 		debugfs_create_file("registers", 0400, map->debugfs,
294 				    map, &regmap_map_fops);
295 		debugfs_create_file("access", 0400, map->debugfs,
296 				    map, &regmap_access_fops);
297 	}
298 
299 	if (map->cache_type) {
300 		debugfs_create_bool("cache_only", 0400, map->debugfs,
301 				    &map->cache_only);
302 		debugfs_create_bool("cache_dirty", 0400, map->debugfs,
303 				    &map->cache_dirty);
304 		debugfs_create_bool("cache_bypass", 0400, map->debugfs,
305 				    &map->cache_bypass);
306 	}
307 
308 	next = rb_first(&map->range_tree);
309 	while (next) {
310 		range_node = rb_entry(next, struct regmap_range_node, node);
311 
312 		if (range_node->name)
313 			debugfs_create_file(range_node->name, 0400,
314 					    map->debugfs, range_node,
315 					    &regmap_range_fops);
316 
317 		next = rb_next(&range_node->node);
318 	}
319 }
320 
321 void regmap_debugfs_exit(struct regmap *map)
322 {
323 	debugfs_remove_recursive(map->debugfs);
324 	kfree(map->debugfs_name);
325 }
326 
327 void regmap_debugfs_initcall(void)
328 {
329 	regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
330 	if (!regmap_debugfs_root) {
331 		pr_warn("regmap: Failed to create debugfs root\n");
332 		return;
333 	}
334 }
335