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 return snprintf(NULL, 0, "%x", max_val);
29 static ssize_t regmap_name_read_file(struct file *file,
30 char __user *user_buf, size_t count,
33 struct regmap *map = file->private_data;
37 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
41 ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
47 ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
52 static const struct file_operations regmap_name_fops = {
54 .read = regmap_name_read_file,
55 .llseek = default_llseek,
58 static void regmap_debugfs_free_dump_cache(struct regmap *map)
60 struct regmap_debugfs_off_cache *c;
62 while (!list_empty(&map->debugfs_off_cache)) {
63 c = list_first_entry(&map->debugfs_off_cache,
64 struct regmap_debugfs_off_cache,
72 * Work out where the start offset maps into register numbers, bearing
73 * in mind that we suppress hidden registers.
75 static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
80 struct regmap_debugfs_off_cache *c = NULL;
83 unsigned int fpos_offset;
84 unsigned int reg_offset;
87 * If we don't have a cache build one so we don't have to do a
88 * linear scan each time.
90 mutex_lock(&map->cache_lock);
92 if (list_empty(&map->debugfs_off_cache)) {
93 for (; i <= map->max_register; i += map->reg_stride) {
94 /* Skip unprinted registers, closing off cache entry */
95 if (!regmap_readable(map, i) ||
96 regmap_precious(map, i)) {
99 c->max_reg = i - map->reg_stride;
100 list_add_tail(&c->list,
101 &map->debugfs_off_cache);
108 /* No cache entry? Start a new one */
110 c = kzalloc(sizeof(*c), GFP_KERNEL);
112 regmap_debugfs_free_dump_cache(map);
113 mutex_unlock(&map->cache_lock);
120 p += map->debugfs_tot_len;
124 /* Close the last entry off if we didn't scan beyond it */
127 c->max_reg = i - map->reg_stride;
128 list_add_tail(&c->list,
129 &map->debugfs_off_cache);
133 * This should never happen; we return above if we fail to
134 * allocate and we should never be in this code if there are
135 * no registers at all.
137 WARN_ON(list_empty(&map->debugfs_off_cache));
140 /* Find the relevant block:offset */
141 list_for_each_entry(c, &map->debugfs_off_cache, list) {
142 if (from >= c->min && from <= c->max) {
143 fpos_offset = from - c->min;
144 reg_offset = fpos_offset / map->debugfs_tot_len;
145 *pos = c->min + (reg_offset * map->debugfs_tot_len);
146 mutex_unlock(&map->cache_lock);
147 return c->base_reg + reg_offset;
153 mutex_unlock(&map->cache_lock);
158 static inline void regmap_calc_tot_len(struct regmap *map,
159 void *buf, size_t count)
161 /* Calculate the length of a fixed format */
162 if (!map->debugfs_tot_len) {
163 map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
165 map->debugfs_val_len = 2 * map->format.val_bytes;
166 map->debugfs_tot_len = map->debugfs_reg_len +
167 map->debugfs_val_len + 3; /* : \n */
171 static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
172 unsigned int to, char __user *user_buf,
173 size_t count, loff_t *ppos)
180 unsigned int val, start_reg;
182 if (*ppos < 0 || !count)
185 buf = kmalloc(count, GFP_KERNEL);
189 regmap_calc_tot_len(map, buf, count);
191 /* Work out which register we're starting at */
192 start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
194 for (i = start_reg; i <= to; i += map->reg_stride) {
195 if (!regmap_readable(map, i))
198 if (regmap_precious(map, i))
201 /* If we're in the region the user is trying to read */
203 /* ...but not beyond it */
204 if (buf_pos + map->debugfs_tot_len > count)
207 /* Format the register */
208 snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
209 map->debugfs_reg_len, i - from);
210 buf_pos += map->debugfs_reg_len + 2;
212 /* Format the value, write all X if we can't read */
213 ret = regmap_read(map, i, &val);
215 snprintf(buf + buf_pos, count - buf_pos,
216 "%.*x", map->debugfs_val_len, val);
218 memset(buf + buf_pos, 'X',
219 map->debugfs_val_len);
220 buf_pos += 2 * map->format.val_bytes;
222 buf[buf_pos++] = '\n';
224 p += map->debugfs_tot_len;
229 if (copy_to_user(user_buf, buf, buf_pos)) {
241 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
242 size_t count, loff_t *ppos)
244 struct regmap *map = file->private_data;
246 return regmap_read_debugfs(map, 0, map->max_register, user_buf,
250 #undef REGMAP_ALLOW_WRITE_DEBUGFS
251 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
253 * This can be dangerous especially when we have clients such as
254 * PMICs, therefore don't provide any real compile time configuration option
255 * for this feature, people who want to use this will need to modify
256 * the source code directly.
258 static ssize_t regmap_map_write_file(struct file *file,
259 const char __user *user_buf,
260 size_t count, loff_t *ppos)
265 unsigned long reg, value;
266 struct regmap *map = file->private_data;
269 buf_size = min(count, (sizeof(buf)-1));
270 if (copy_from_user(buf, user_buf, buf_size))
274 while (*start == ' ')
276 reg = simple_strtoul(start, &start, 16);
277 while (*start == ' ')
279 if (strict_strtoul(start, 16, &value))
282 /* Userspace has been fiddling around behind the kernel's back */
283 add_taint(TAINT_USER, LOCKDEP_NOW_UNRELIABLE);
285 ret = regmap_write(map, reg, value);
291 #define regmap_map_write_file NULL
294 static const struct file_operations regmap_map_fops = {
296 .read = regmap_map_read_file,
297 .write = regmap_map_write_file,
298 .llseek = default_llseek,
301 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
302 size_t count, loff_t *ppos)
304 struct regmap_range_node *range = file->private_data;
305 struct regmap *map = range->map;
307 return regmap_read_debugfs(map, range->range_min, range->range_max,
308 user_buf, count, ppos);
311 static const struct file_operations regmap_range_fops = {
313 .read = regmap_range_read_file,
314 .llseek = default_llseek,
317 static ssize_t regmap_reg_ranges_read_file(struct file *file,
318 char __user *user_buf, size_t count,
321 struct regmap *map = file->private_data;
322 struct regmap_debugfs_off_cache *c;
329 if (*ppos < 0 || !count)
332 buf = kmalloc(count, GFP_KERNEL);
336 entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
342 /* While we are at it, build the register dump cache
343 * now so the read() operation on the `registers' file
344 * can benefit from using the cache. We do not care
345 * about the file position information that is contained
346 * in the cache, just about the actual register blocks */
347 regmap_calc_tot_len(map, buf, count);
348 regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
350 /* Reset file pointer as the fixed-format of the `registers'
351 * file is not compatible with the `range' file */
353 mutex_lock(&map->cache_lock);
354 list_for_each_entry(c, &map->debugfs_off_cache, list) {
355 snprintf(entry, PAGE_SIZE, "%x-%x",
356 c->base_reg, c->max_reg);
358 if (buf_pos + 1 + strlen(entry) > count)
360 snprintf(buf + buf_pos, count - buf_pos,
362 buf_pos += strlen(entry);
366 p += strlen(entry) + 1;
368 mutex_unlock(&map->cache_lock);
373 if (copy_to_user(user_buf, buf, buf_pos)) {
384 static const struct file_operations regmap_reg_ranges_fops = {
386 .read = regmap_reg_ranges_read_file,
387 .llseek = default_llseek,
390 static ssize_t regmap_access_read_file(struct file *file,
391 char __user *user_buf, size_t count,
394 int reg_len, tot_len;
399 struct regmap *map = file->private_data;
402 if (*ppos < 0 || !count)
405 buf = kmalloc(count, GFP_KERNEL);
409 /* Calculate the length of a fixed format */
410 reg_len = regmap_calc_reg_len(map->max_register, buf, count);
411 tot_len = reg_len + 10; /* ': R W V P\n' */
413 for (i = 0; i <= map->max_register; i += map->reg_stride) {
414 /* Ignore registers which are neither readable nor writable */
415 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
418 /* If we're in the region the user is trying to read */
420 /* ...but not beyond it */
421 if (buf_pos + tot_len + 1 >= count)
424 /* Format the register */
425 snprintf(buf + buf_pos, count - buf_pos,
426 "%.*x: %c %c %c %c\n",
428 regmap_readable(map, i) ? 'y' : 'n',
429 regmap_writeable(map, i) ? 'y' : 'n',
430 regmap_volatile(map, i) ? 'y' : 'n',
431 regmap_precious(map, i) ? 'y' : 'n');
440 if (copy_to_user(user_buf, buf, buf_pos)) {
452 static const struct file_operations regmap_access_fops = {
454 .read = regmap_access_read_file,
455 .llseek = default_llseek,
458 void regmap_debugfs_init(struct regmap *map, const char *name)
460 struct rb_node *next;
461 struct regmap_range_node *range_node;
462 const char *devname = "dummy";
464 INIT_LIST_HEAD(&map->debugfs_off_cache);
465 mutex_init(&map->cache_lock);
468 devname = dev_name(map->dev);
471 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
473 name = map->debugfs_name;
478 map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
480 dev_warn(map->dev, "Failed to create debugfs directory\n");
484 debugfs_create_file("name", 0400, map->debugfs,
485 map, ®map_name_fops);
487 debugfs_create_file("range", 0400, map->debugfs,
488 map, ®map_reg_ranges_fops);
490 if (map->max_register) {
491 debugfs_create_file("registers", 0400, map->debugfs,
492 map, ®map_map_fops);
493 debugfs_create_file("access", 0400, map->debugfs,
494 map, ®map_access_fops);
497 if (map->cache_type) {
498 debugfs_create_bool("cache_only", 0400, map->debugfs,
500 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
502 debugfs_create_bool("cache_bypass", 0400, map->debugfs,
506 next = rb_first(&map->range_tree);
508 range_node = rb_entry(next, struct regmap_range_node, node);
510 if (range_node->name)
511 debugfs_create_file(range_node->name, 0400,
512 map->debugfs, range_node,
515 next = rb_next(&range_node->node);
519 void regmap_debugfs_exit(struct regmap *map)
521 debugfs_remove_recursive(map->debugfs);
522 mutex_lock(&map->cache_lock);
523 regmap_debugfs_free_dump_cache(map);
524 mutex_unlock(&map->cache_lock);
525 kfree(map->debugfs_name);
528 void regmap_debugfs_initcall(void)
530 regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
531 if (!regmap_debugfs_root) {
532 pr_warn("regmap: Failed to create debugfs root\n");