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>
18 #include <linux/list.h>
22 struct regmap_debugfs_node {
25 struct list_head link;
28 static struct dentry *regmap_debugfs_root;
29 static LIST_HEAD(regmap_debugfs_early_list);
30 static DEFINE_MUTEX(regmap_debugfs_early_lock);
32 /* Calculate the length of a fixed format */
33 static size_t regmap_calc_reg_len(int max_val)
35 return snprintf(NULL, 0, "%x", max_val);
38 static ssize_t regmap_name_read_file(struct file *file,
39 char __user *user_buf, size_t count,
42 struct regmap *map = file->private_data;
46 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
50 ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
56 ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
61 static const struct file_operations regmap_name_fops = {
63 .read = regmap_name_read_file,
64 .llseek = default_llseek,
67 static void regmap_debugfs_free_dump_cache(struct regmap *map)
69 struct regmap_debugfs_off_cache *c;
71 while (!list_empty(&map->debugfs_off_cache)) {
72 c = list_first_entry(&map->debugfs_off_cache,
73 struct regmap_debugfs_off_cache,
80 static bool regmap_printable(struct regmap *map, unsigned int reg)
82 if (regmap_precious(map, reg))
85 if (!regmap_readable(map, reg) && !regmap_cached(map, reg))
92 * Work out where the start offset maps into register numbers, bearing
93 * in mind that we suppress hidden registers.
95 static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
100 struct regmap_debugfs_off_cache *c = NULL;
103 unsigned int fpos_offset;
104 unsigned int reg_offset;
106 /* Suppress the cache if we're using a subrange */
111 * If we don't have a cache build one so we don't have to do a
112 * linear scan each time.
114 mutex_lock(&map->cache_lock);
116 if (list_empty(&map->debugfs_off_cache)) {
117 for (; i <= map->max_register; i += map->reg_stride) {
118 /* Skip unprinted registers, closing off cache entry */
119 if (!regmap_printable(map, i)) {
122 c->max_reg = i - map->reg_stride;
123 list_add_tail(&c->list,
124 &map->debugfs_off_cache);
131 /* No cache entry? Start a new one */
133 c = kzalloc(sizeof(*c), GFP_KERNEL);
135 regmap_debugfs_free_dump_cache(map);
136 mutex_unlock(&map->cache_lock);
143 p += map->debugfs_tot_len;
147 /* Close the last entry off if we didn't scan beyond it */
150 c->max_reg = i - map->reg_stride;
151 list_add_tail(&c->list,
152 &map->debugfs_off_cache);
156 * This should never happen; we return above if we fail to
157 * allocate and we should never be in this code if there are
158 * no registers at all.
160 WARN_ON(list_empty(&map->debugfs_off_cache));
163 /* Find the relevant block:offset */
164 list_for_each_entry(c, &map->debugfs_off_cache, list) {
165 if (from >= c->min && from <= c->max) {
166 fpos_offset = from - c->min;
167 reg_offset = fpos_offset / map->debugfs_tot_len;
168 *pos = c->min + (reg_offset * map->debugfs_tot_len);
169 mutex_unlock(&map->cache_lock);
170 return c->base_reg + (reg_offset * map->reg_stride);
176 mutex_unlock(&map->cache_lock);
181 static inline void regmap_calc_tot_len(struct regmap *map,
182 void *buf, size_t count)
184 /* Calculate the length of a fixed format */
185 if (!map->debugfs_tot_len) {
186 map->debugfs_reg_len = regmap_calc_reg_len(map->max_register),
187 map->debugfs_val_len = 2 * map->format.val_bytes;
188 map->debugfs_tot_len = map->debugfs_reg_len +
189 map->debugfs_val_len + 3; /* : \n */
193 static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
194 unsigned int to, char __user *user_buf,
195 size_t count, loff_t *ppos)
202 unsigned int val, start_reg;
204 if (*ppos < 0 || !count)
207 if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
208 count = PAGE_SIZE << (MAX_ORDER - 1);
210 buf = kmalloc(count, GFP_KERNEL);
214 regmap_calc_tot_len(map, buf, count);
216 /* Work out which register we're starting at */
217 start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
219 for (i = start_reg; i <= to; i += map->reg_stride) {
220 if (!regmap_readable(map, i) && !regmap_cached(map, i))
223 if (regmap_precious(map, i))
226 /* If we're in the region the user is trying to read */
228 /* ...but not beyond it */
229 if (buf_pos + map->debugfs_tot_len > count)
232 /* Format the register */
233 snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
234 map->debugfs_reg_len, i - from);
235 buf_pos += map->debugfs_reg_len + 2;
237 /* Format the value, write all X if we can't read */
238 ret = regmap_read(map, i, &val);
240 snprintf(buf + buf_pos, count - buf_pos,
241 "%.*x", map->debugfs_val_len, val);
243 memset(buf + buf_pos, 'X',
244 map->debugfs_val_len);
245 buf_pos += 2 * map->format.val_bytes;
247 buf[buf_pos++] = '\n';
249 p += map->debugfs_tot_len;
254 if (copy_to_user(user_buf, buf, buf_pos)) {
266 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
267 size_t count, loff_t *ppos)
269 struct regmap *map = file->private_data;
271 return regmap_read_debugfs(map, 0, map->max_register, user_buf,
275 #undef REGMAP_ALLOW_WRITE_DEBUGFS
276 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
278 * This can be dangerous especially when we have clients such as
279 * PMICs, therefore don't provide any real compile time configuration option
280 * for this feature, people who want to use this will need to modify
281 * the source code directly.
283 static ssize_t regmap_map_write_file(struct file *file,
284 const char __user *user_buf,
285 size_t count, loff_t *ppos)
290 unsigned long reg, value;
291 struct regmap *map = file->private_data;
294 buf_size = min(count, (sizeof(buf)-1));
295 if (copy_from_user(buf, user_buf, buf_size))
299 while (*start == ' ')
301 reg = simple_strtoul(start, &start, 16);
302 while (*start == ' ')
304 if (kstrtoul(start, 16, &value))
307 /* Userspace has been fiddling around behind the kernel's back */
308 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
310 ret = regmap_write(map, reg, value);
316 #define regmap_map_write_file NULL
319 static const struct file_operations regmap_map_fops = {
321 .read = regmap_map_read_file,
322 .write = regmap_map_write_file,
323 .llseek = default_llseek,
326 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
327 size_t count, loff_t *ppos)
329 struct regmap_range_node *range = file->private_data;
330 struct regmap *map = range->map;
332 return regmap_read_debugfs(map, range->range_min, range->range_max,
333 user_buf, count, ppos);
336 static const struct file_operations regmap_range_fops = {
338 .read = regmap_range_read_file,
339 .llseek = default_llseek,
342 static ssize_t regmap_reg_ranges_read_file(struct file *file,
343 char __user *user_buf, size_t count,
346 struct regmap *map = file->private_data;
347 struct regmap_debugfs_off_cache *c;
355 if (*ppos < 0 || !count)
358 if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
359 count = PAGE_SIZE << (MAX_ORDER - 1);
361 buf = kmalloc(count, GFP_KERNEL);
365 entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
371 /* While we are at it, build the register dump cache
372 * now so the read() operation on the `registers' file
373 * can benefit from using the cache. We do not care
374 * about the file position information that is contained
375 * in the cache, just about the actual register blocks */
376 regmap_calc_tot_len(map, buf, count);
377 regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
379 /* Reset file pointer as the fixed-format of the `registers'
380 * file is not compatible with the `range' file */
382 mutex_lock(&map->cache_lock);
383 list_for_each_entry(c, &map->debugfs_off_cache, list) {
384 entry_len = snprintf(entry, PAGE_SIZE, "%x-%x\n",
385 c->base_reg, c->max_reg);
387 if (buf_pos + entry_len > count)
389 memcpy(buf + buf_pos, entry, entry_len);
390 buf_pos += entry_len;
394 mutex_unlock(&map->cache_lock);
399 if (copy_to_user(user_buf, buf, buf_pos)) {
410 static const struct file_operations regmap_reg_ranges_fops = {
412 .read = regmap_reg_ranges_read_file,
413 .llseek = default_llseek,
416 static int regmap_access_show(struct seq_file *s, void *ignored)
418 struct regmap *map = s->private;
421 reg_len = regmap_calc_reg_len(map->max_register);
423 for (i = 0; i <= map->max_register; i += map->reg_stride) {
424 /* Ignore registers which are neither readable nor writable */
425 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
428 /* Format the register */
429 seq_printf(s, "%.*x: %c %c %c %c\n", reg_len, i,
430 regmap_readable(map, i) ? 'y' : 'n',
431 regmap_writeable(map, i) ? 'y' : 'n',
432 regmap_volatile(map, i) ? 'y' : 'n',
433 regmap_precious(map, i) ? 'y' : 'n');
439 static int access_open(struct inode *inode, struct file *file)
441 return single_open(file, regmap_access_show, inode->i_private);
444 static const struct file_operations regmap_access_fops = {
448 .release = single_release,
451 static ssize_t regmap_cache_only_write_file(struct file *file,
452 const char __user *user_buf,
453 size_t count, loff_t *ppos)
455 struct regmap *map = container_of(file->private_data,
456 struct regmap, cache_only);
458 bool was_enabled, require_sync = false;
461 map->lock(map->lock_arg);
463 was_enabled = map->cache_only;
465 result = debugfs_write_file_bool(file, user_buf, count, ppos);
467 map->unlock(map->lock_arg);
471 if (map->cache_only && !was_enabled) {
472 dev_warn(map->dev, "debugfs cache_only=Y forced\n");
473 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
474 } else if (!map->cache_only && was_enabled) {
475 dev_warn(map->dev, "debugfs cache_only=N forced: syncing cache\n");
479 map->unlock(map->lock_arg);
482 err = regcache_sync(map);
484 dev_err(map->dev, "Failed to sync cache %d\n", err);
490 static const struct file_operations regmap_cache_only_fops = {
492 .read = debugfs_read_file_bool,
493 .write = regmap_cache_only_write_file,
496 static ssize_t regmap_cache_bypass_write_file(struct file *file,
497 const char __user *user_buf,
498 size_t count, loff_t *ppos)
500 struct regmap *map = container_of(file->private_data,
501 struct regmap, cache_bypass);
505 map->lock(map->lock_arg);
507 was_enabled = map->cache_bypass;
509 result = debugfs_write_file_bool(file, user_buf, count, ppos);
513 if (map->cache_bypass && !was_enabled) {
514 dev_warn(map->dev, "debugfs cache_bypass=Y forced\n");
515 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
516 } else if (!map->cache_bypass && was_enabled) {
517 dev_warn(map->dev, "debugfs cache_bypass=N forced\n");
521 map->unlock(map->lock_arg);
526 static const struct file_operations regmap_cache_bypass_fops = {
528 .read = debugfs_read_file_bool,
529 .write = regmap_cache_bypass_write_file,
532 void regmap_debugfs_init(struct regmap *map, const char *name)
534 struct rb_node *next;
535 struct regmap_range_node *range_node;
536 const char *devname = "dummy";
538 /* If we don't have the debugfs root yet, postpone init */
539 if (!regmap_debugfs_root) {
540 struct regmap_debugfs_node *node;
541 node = kzalloc(sizeof(*node), GFP_KERNEL);
546 mutex_lock(®map_debugfs_early_lock);
547 list_add(&node->link, ®map_debugfs_early_list);
548 mutex_unlock(®map_debugfs_early_lock);
552 INIT_LIST_HEAD(&map->debugfs_off_cache);
553 mutex_init(&map->cache_lock);
556 devname = dev_name(map->dev);
559 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
561 name = map->debugfs_name;
566 map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
568 dev_warn(map->dev, "Failed to create debugfs directory\n");
572 debugfs_create_file("name", 0400, map->debugfs,
573 map, ®map_name_fops);
575 debugfs_create_file("range", 0400, map->debugfs,
576 map, ®map_reg_ranges_fops);
578 if (map->max_register || regmap_readable(map, 0)) {
579 umode_t registers_mode;
581 #if defined(REGMAP_ALLOW_WRITE_DEBUGFS)
582 registers_mode = 0600;
584 registers_mode = 0400;
587 debugfs_create_file("registers", registers_mode, map->debugfs,
588 map, ®map_map_fops);
589 debugfs_create_file("access", 0400, map->debugfs,
590 map, ®map_access_fops);
593 if (map->cache_type) {
594 debugfs_create_file("cache_only", 0600, map->debugfs,
595 &map->cache_only, ®map_cache_only_fops);
596 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
598 debugfs_create_file("cache_bypass", 0600, map->debugfs,
600 ®map_cache_bypass_fops);
603 next = rb_first(&map->range_tree);
605 range_node = rb_entry(next, struct regmap_range_node, node);
607 if (range_node->name)
608 debugfs_create_file(range_node->name, 0400,
609 map->debugfs, range_node,
612 next = rb_next(&range_node->node);
615 if (map->cache_ops && map->cache_ops->debugfs_init)
616 map->cache_ops->debugfs_init(map);
619 void regmap_debugfs_exit(struct regmap *map)
622 debugfs_remove_recursive(map->debugfs);
623 mutex_lock(&map->cache_lock);
624 regmap_debugfs_free_dump_cache(map);
625 mutex_unlock(&map->cache_lock);
626 kfree(map->debugfs_name);
628 struct regmap_debugfs_node *node, *tmp;
630 mutex_lock(®map_debugfs_early_lock);
631 list_for_each_entry_safe(node, tmp, ®map_debugfs_early_list,
633 if (node->map == map) {
634 list_del(&node->link);
638 mutex_unlock(®map_debugfs_early_lock);
642 void regmap_debugfs_initcall(void)
644 struct regmap_debugfs_node *node, *tmp;
646 regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
647 if (!regmap_debugfs_root) {
648 pr_warn("regmap: Failed to create debugfs root\n");
652 mutex_lock(®map_debugfs_early_lock);
653 list_for_each_entry_safe(node, tmp, ®map_debugfs_early_list, link) {
654 regmap_debugfs_init(node->map, node->name);
655 list_del(&node->link);
658 mutex_unlock(®map_debugfs_early_lock);