2 * Register map access API - debugfs
4 * Copyright 2011 Wolfson Microelectronics plc
6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
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.
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>
21 static struct dentry *regmap_debugfs_root;
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)
26 snprintf(buf, buf_size, "%x", max_val);
30 static ssize_t regmap_name_read_file(struct file *file,
31 char __user *user_buf, size_t count,
34 struct regmap *map = file->private_data;
38 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
42 ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
48 ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
53 static const struct file_operations regmap_name_fops = {
55 .read = regmap_name_read_file,
56 .llseek = default_llseek,
59 static void regmap_debugfs_free_dump_cache(struct regmap *map)
61 struct regmap_debugfs_off_cache *c;
63 while (!list_empty(&map->debugfs_off_cache)) {
64 c = list_first_entry(&map->debugfs_off_cache,
65 struct regmap_debugfs_off_cache,
73 * Work out where the start offset maps into register numbers, bearing
74 * in mind that we suppress hidden registers.
76 static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
81 struct regmap_debugfs_off_cache *c = NULL;
84 unsigned int fpos_offset;
85 unsigned int reg_offset;
88 * If we don't have a cache build one so we don't have to do a
89 * linear scan each time.
91 mutex_lock(&map->cache_lock);
93 if (list_empty(&map->debugfs_off_cache)) {
94 for (; i <= map->max_register; i += map->reg_stride) {
95 /* Skip unprinted registers, closing off cache entry */
96 if (!regmap_readable(map, i) ||
97 regmap_precious(map, i)) {
100 c->max_reg = i - map->reg_stride;
101 list_add_tail(&c->list,
102 &map->debugfs_off_cache);
109 /* No cache entry? Start a new one */
111 c = kzalloc(sizeof(*c), GFP_KERNEL);
113 regmap_debugfs_free_dump_cache(map);
114 mutex_unlock(&map->cache_lock);
121 p += map->debugfs_tot_len;
125 /* Close the last entry off if we didn't scan beyond it */
128 c->max_reg = i - map->reg_stride;
129 list_add_tail(&c->list,
130 &map->debugfs_off_cache);
134 * This should never happen; we return above if we fail to
135 * allocate and we should never be in this code if there are
136 * no registers at all.
138 WARN_ON(list_empty(&map->debugfs_off_cache));
141 /* Find the relevant block:offset */
142 list_for_each_entry(c, &map->debugfs_off_cache, list) {
143 if (from >= c->min && from <= c->max) {
144 fpos_offset = from - c->min;
145 reg_offset = fpos_offset / map->debugfs_tot_len;
146 *pos = c->min + (reg_offset * map->debugfs_tot_len);
147 mutex_unlock(&map->cache_lock);
148 return c->base_reg + reg_offset;
154 mutex_unlock(&map->cache_lock);
159 static inline void regmap_calc_tot_len(struct regmap *map,
160 void *buf, size_t count)
162 /* Calculate the length of a fixed format */
163 if (!map->debugfs_tot_len) {
164 map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
166 map->debugfs_val_len = 2 * map->format.val_bytes;
167 map->debugfs_tot_len = map->debugfs_reg_len +
168 map->debugfs_val_len + 3; /* : \n */
172 static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
173 unsigned int to, char __user *user_buf,
174 size_t count, loff_t *ppos)
181 unsigned int val, start_reg;
183 if (*ppos < 0 || !count)
186 buf = kmalloc(count, GFP_KERNEL);
190 regmap_calc_tot_len(map, buf, count);
192 /* Work out which register we're starting at */
193 start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
195 for (i = start_reg; i <= to; i += map->reg_stride) {
196 if (!regmap_readable(map, i))
199 if (regmap_precious(map, i))
202 /* If we're in the region the user is trying to read */
204 /* ...but not beyond it */
205 if (buf_pos + map->debugfs_tot_len > count)
208 /* Format the register */
209 snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
210 map->debugfs_reg_len, i - from);
211 buf_pos += map->debugfs_reg_len + 2;
213 /* Format the value, write all X if we can't read */
214 ret = regmap_read(map, i, &val);
216 snprintf(buf + buf_pos, count - buf_pos,
217 "%.*x", map->debugfs_val_len, val);
219 memset(buf + buf_pos, 'X',
220 map->debugfs_val_len);
221 buf_pos += 2 * map->format.val_bytes;
223 buf[buf_pos++] = '\n';
225 p += map->debugfs_tot_len;
230 if (copy_to_user(user_buf, buf, buf_pos)) {
242 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
243 size_t count, loff_t *ppos)
245 struct regmap *map = file->private_data;
247 return regmap_read_debugfs(map, 0, map->max_register, user_buf,
251 #undef REGMAP_ALLOW_WRITE_DEBUGFS
252 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
254 * This can be dangerous especially when we have clients such as
255 * PMICs, therefore don't provide any real compile time configuration option
256 * for this feature, people who want to use this will need to modify
257 * the source code directly.
259 static ssize_t regmap_map_write_file(struct file *file,
260 const char __user *user_buf,
261 size_t count, loff_t *ppos)
266 unsigned long reg, value;
267 struct regmap *map = file->private_data;
270 buf_size = min(count, (sizeof(buf)-1));
271 if (copy_from_user(buf, user_buf, buf_size))
275 while (*start == ' ')
277 reg = simple_strtoul(start, &start, 16);
278 while (*start == ' ')
280 if (strict_strtoul(start, 16, &value))
283 /* Userspace has been fiddling around behind the kernel's back */
284 add_taint(TAINT_USER, LOCKDEP_NOW_UNRELIABLE);
286 ret = regmap_write(map, reg, value);
292 #define regmap_map_write_file NULL
295 static const struct file_operations regmap_map_fops = {
297 .read = regmap_map_read_file,
298 .write = regmap_map_write_file,
299 .llseek = default_llseek,
302 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
303 size_t count, loff_t *ppos)
305 struct regmap_range_node *range = file->private_data;
306 struct regmap *map = range->map;
308 return regmap_read_debugfs(map, range->range_min, range->range_max,
309 user_buf, count, ppos);
312 static const struct file_operations regmap_range_fops = {
314 .read = regmap_range_read_file,
315 .llseek = default_llseek,
318 static ssize_t regmap_reg_ranges_read_file(struct file *file,
319 char __user *user_buf, size_t count,
322 struct regmap *map = file->private_data;
323 struct regmap_debugfs_off_cache *c;
330 if (*ppos < 0 || !count)
333 buf = kmalloc(count, GFP_KERNEL);
337 entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
343 /* While we are at it, build the register dump cache
344 * now so the read() operation on the `registers' file
345 * can benefit from using the cache. We do not care
346 * about the file position information that is contained
347 * in the cache, just about the actual register blocks */
348 regmap_calc_tot_len(map, buf, count);
349 regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
351 /* Reset file pointer as the fixed-format of the `registers'
352 * file is not compatible with the `range' file */
354 mutex_lock(&map->cache_lock);
355 list_for_each_entry(c, &map->debugfs_off_cache, list) {
356 snprintf(entry, PAGE_SIZE, "%x-%x",
357 c->base_reg, c->max_reg);
359 if (buf_pos + 1 + strlen(entry) > count)
361 snprintf(buf + buf_pos, count - buf_pos,
363 buf_pos += strlen(entry);
367 p += strlen(entry) + 1;
369 mutex_unlock(&map->cache_lock);
374 if (copy_to_user(user_buf, buf, buf_pos)) {
385 static const struct file_operations regmap_reg_ranges_fops = {
387 .read = regmap_reg_ranges_read_file,
388 .llseek = default_llseek,
391 static ssize_t regmap_access_read_file(struct file *file,
392 char __user *user_buf, size_t count,
395 int reg_len, tot_len;
400 struct regmap *map = file->private_data;
403 if (*ppos < 0 || !count)
406 buf = kmalloc(count, GFP_KERNEL);
410 /* Calculate the length of a fixed format */
411 reg_len = regmap_calc_reg_len(map->max_register, buf, count);
412 tot_len = reg_len + 10; /* ': R W V P\n' */
414 for (i = 0; i <= map->max_register; i += map->reg_stride) {
415 /* Ignore registers which are neither readable nor writable */
416 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
419 /* If we're in the region the user is trying to read */
421 /* ...but not beyond it */
422 if (buf_pos >= count - 1 - tot_len)
425 /* Format the register */
426 snprintf(buf + buf_pos, count - buf_pos,
427 "%.*x: %c %c %c %c\n",
429 regmap_readable(map, i) ? 'y' : 'n',
430 regmap_writeable(map, i) ? 'y' : 'n',
431 regmap_volatile(map, i) ? 'y' : 'n',
432 regmap_precious(map, i) ? 'y' : 'n');
441 if (copy_to_user(user_buf, buf, buf_pos)) {
453 static const struct file_operations regmap_access_fops = {
455 .read = regmap_access_read_file,
456 .llseek = default_llseek,
459 void regmap_debugfs_init(struct regmap *map, const char *name)
461 struct rb_node *next;
462 struct regmap_range_node *range_node;
464 INIT_LIST_HEAD(&map->debugfs_off_cache);
465 mutex_init(&map->cache_lock);
468 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
469 dev_name(map->dev), name);
470 name = map->debugfs_name;
472 name = dev_name(map->dev);
475 map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
477 dev_warn(map->dev, "Failed to create debugfs directory\n");
481 debugfs_create_file("name", 0400, map->debugfs,
482 map, ®map_name_fops);
484 debugfs_create_file("range", 0400, map->debugfs,
485 map, ®map_reg_ranges_fops);
487 if (map->max_register) {
488 debugfs_create_file("registers", 0400, map->debugfs,
489 map, ®map_map_fops);
490 debugfs_create_file("access", 0400, map->debugfs,
491 map, ®map_access_fops);
494 if (map->cache_type) {
495 debugfs_create_bool("cache_only", 0400, map->debugfs,
497 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
499 debugfs_create_bool("cache_bypass", 0400, map->debugfs,
503 next = rb_first(&map->range_tree);
505 range_node = rb_entry(next, struct regmap_range_node, node);
507 if (range_node->name)
508 debugfs_create_file(range_node->name, 0400,
509 map->debugfs, range_node,
512 next = rb_next(&range_node->node);
516 void regmap_debugfs_exit(struct regmap *map)
518 debugfs_remove_recursive(map->debugfs);
519 mutex_lock(&map->cache_lock);
520 regmap_debugfs_free_dump_cache(map);
521 mutex_unlock(&map->cache_lock);
522 kfree(map->debugfs_name);
525 void regmap_debugfs_initcall(void)
527 regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
528 if (!regmap_debugfs_root) {
529 pr_warn("regmap: Failed to create debugfs root\n");