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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#include <linux/list.h>
19
20#include "internal.h"
21
22struct regmap_debugfs_node {
23 struct regmap *map;
24 const char *name;
25 struct list_head link;
26};
27
28static unsigned int dummy_index;
29static struct dentry *regmap_debugfs_root;
30static LIST_HEAD(regmap_debugfs_early_list);
31static DEFINE_MUTEX(regmap_debugfs_early_lock);
32
33/* Calculate the length of a fixed format */
34static size_t regmap_calc_reg_len(int max_val)
35{
36 return snprintf(NULL, 0, "%x", max_val);
37}
38
39static ssize_t regmap_name_read_file(struct file *file,
40 char __user *user_buf, size_t count,
41 loff_t *ppos)
42{
43 struct regmap *map = file->private_data;
44 const char *name = "nodev";
45 int ret;
46 char *buf;
47
48 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
49 if (!buf)
50 return -ENOMEM;
51
52 if (map->dev && map->dev->driver)
53 name = map->dev->driver->name;
54
55 ret = snprintf(buf, PAGE_SIZE, "%s\n", name);
56 if (ret < 0) {
57 kfree(buf);
58 return ret;
59 }
60
61 ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
62 kfree(buf);
63 return ret;
64}
65
66static const struct file_operations regmap_name_fops = {
67 .open = simple_open,
68 .read = regmap_name_read_file,
69 .llseek = default_llseek,
70};
71
72static void regmap_debugfs_free_dump_cache(struct regmap *map)
73{
74 struct regmap_debugfs_off_cache *c;
75
76 while (!list_empty(&map->debugfs_off_cache)) {
77 c = list_first_entry(&map->debugfs_off_cache,
78 struct regmap_debugfs_off_cache,
79 list);
80 list_del(&c->list);
81 kfree(c);
82 }
83}
84
85static bool regmap_printable(struct regmap *map, unsigned int reg)
86{
87 if (regmap_precious(map, reg))
88 return false;
89
90 if (!regmap_readable(map, reg) && !regmap_cached(map, reg))
91 return false;
92
93 return true;
94}
95
96/*
97 * Work out where the start offset maps into register numbers, bearing
98 * in mind that we suppress hidden registers.
99 */
100static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
101 unsigned int base,
102 loff_t from,
103 loff_t *pos)
104{
105 struct regmap_debugfs_off_cache *c = NULL;
106 loff_t p = 0;
107 unsigned int i, ret;
108 unsigned int fpos_offset;
109 unsigned int reg_offset;
110
111 /* Suppress the cache if we're using a subrange */
112 if (base)
113 return base;
114
115 /*
116 * If we don't have a cache build one so we don't have to do a
117 * linear scan each time.
118 */
119 mutex_lock(&map->cache_lock);
120 i = base;
121 if (list_empty(&map->debugfs_off_cache)) {
122 for (; i <= map->max_register; i += map->reg_stride) {
123 /* Skip unprinted registers, closing off cache entry */
124 if (!regmap_printable(map, i)) {
125 if (c) {
126 c->max = p - 1;
127 c->max_reg = i - map->reg_stride;
128 list_add_tail(&c->list,
129 &map->debugfs_off_cache);
130 c = NULL;
131 }
132
133 continue;
134 }
135
136 /* No cache entry? Start a new one */
137 if (!c) {
138 c = kzalloc(sizeof(*c), GFP_KERNEL);
139 if (!c) {
140 regmap_debugfs_free_dump_cache(map);
141 mutex_unlock(&map->cache_lock);
142 return base;
143 }
144 c->min = p;
145 c->base_reg = i;
146 }
147
148 p += map->debugfs_tot_len;
149 }
150 }
151
152 /* Close the last entry off if we didn't scan beyond it */
153 if (c) {
154 c->max = p - 1;
155 c->max_reg = i - map->reg_stride;
156 list_add_tail(&c->list,
157 &map->debugfs_off_cache);
158 }
159
160 /*
161 * This should never happen; we return above if we fail to
162 * allocate and we should never be in this code if there are
163 * no registers at all.
164 */
165 WARN_ON(list_empty(&map->debugfs_off_cache));
166 ret = base;
167
168 /* Find the relevant block:offset */
169 list_for_each_entry(c, &map->debugfs_off_cache, list) {
170 if (from >= c->min && from <= c->max) {
171 fpos_offset = from - c->min;
172 reg_offset = fpos_offset / map->debugfs_tot_len;
173 *pos = c->min + (reg_offset * map->debugfs_tot_len);
174 mutex_unlock(&map->cache_lock);
175 return c->base_reg + (reg_offset * map->reg_stride);
176 }
177
178 *pos = c->max;
179 ret = c->max_reg;
180 }
181 mutex_unlock(&map->cache_lock);
182
183 return ret;
184}
185
186static inline void regmap_calc_tot_len(struct regmap *map,
187 void *buf, size_t count)
188{
189 /* Calculate the length of a fixed format */
190 if (!map->debugfs_tot_len) {
191 map->debugfs_reg_len = regmap_calc_reg_len(map->max_register),
192 map->debugfs_val_len = 2 * map->format.val_bytes;
193 map->debugfs_tot_len = map->debugfs_reg_len +
194 map->debugfs_val_len + 3; /* : \n */
195 }
196}
197
198static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
199 unsigned int to, char __user *user_buf,
200 size_t count, loff_t *ppos)
201{
202 size_t buf_pos = 0;
203 loff_t p = *ppos;
204 ssize_t ret;
205 int i;
206 char *buf;
207 unsigned int val, start_reg;
208
209 if (*ppos < 0 || !count)
210 return -EINVAL;
211
212 buf = kmalloc(count, GFP_KERNEL);
213 if (!buf)
214 return -ENOMEM;
215
216 regmap_calc_tot_len(map, buf, count);
217
218 /* Work out which register we're starting at */
219 start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
220
221 for (i = start_reg; i <= to; i += map->reg_stride) {
222 if (!regmap_readable(map, i) && !regmap_cached(map, i))
223 continue;
224
225 if (regmap_precious(map, i))
226 continue;
227
228 /* If we're in the region the user is trying to read */
229 if (p >= *ppos) {
230 /* ...but not beyond it */
231 if (buf_pos + map->debugfs_tot_len > count)
232 break;
233
234 /* Format the register */
235 snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
236 map->debugfs_reg_len, i - from);
237 buf_pos += map->debugfs_reg_len + 2;
238
239 /* Format the value, write all X if we can't read */
240 ret = regmap_read(map, i, &val);
241 if (ret == 0)
242 snprintf(buf + buf_pos, count - buf_pos,
243 "%.*x", map->debugfs_val_len, val);
244 else
245 memset(buf + buf_pos, 'X',
246 map->debugfs_val_len);
247 buf_pos += 2 * map->format.val_bytes;
248
249 buf[buf_pos++] = '\n';
250 }
251 p += map->debugfs_tot_len;
252 }
253
254 ret = buf_pos;
255
256 if (copy_to_user(user_buf, buf, buf_pos)) {
257 ret = -EFAULT;
258 goto out;
259 }
260
261 *ppos += buf_pos;
262
263out:
264 kfree(buf);
265 return ret;
266}
267
268static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
269 size_t count, loff_t *ppos)
270{
271 struct regmap *map = file->private_data;
272
273 return regmap_read_debugfs(map, 0, map->max_register, user_buf,
274 count, ppos);
275}
276
277#undef REGMAP_ALLOW_WRITE_DEBUGFS
278#ifdef REGMAP_ALLOW_WRITE_DEBUGFS
279/*
280 * This can be dangerous especially when we have clients such as
281 * PMICs, therefore don't provide any real compile time configuration option
282 * for this feature, people who want to use this will need to modify
283 * the source code directly.
284 */
285static ssize_t regmap_map_write_file(struct file *file,
286 const char __user *user_buf,
287 size_t count, loff_t *ppos)
288{
289 char buf[32];
290 size_t buf_size;
291 char *start = buf;
292 unsigned long reg, value;
293 struct regmap *map = file->private_data;
294 int ret;
295
296 buf_size = min(count, (sizeof(buf)-1));
297 if (copy_from_user(buf, user_buf, buf_size))
298 return -EFAULT;
299 buf[buf_size] = 0;
300
301 while (*start == ' ')
302 start++;
303 reg = simple_strtoul(start, &start, 16);
304 while (*start == ' ')
305 start++;
306 if (kstrtoul(start, 16, &value))
307 return -EINVAL;
308
309 /* Userspace has been fiddling around behind the kernel's back */
310 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
311
312 ret = regmap_write(map, reg, value);
313 if (ret < 0)
314 return ret;
315 return buf_size;
316}
317#else
318#define regmap_map_write_file NULL
319#endif
320
321static const struct file_operations regmap_map_fops = {
322 .open = simple_open,
323 .read = regmap_map_read_file,
324 .write = regmap_map_write_file,
325 .llseek = default_llseek,
326};
327
328static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
329 size_t count, loff_t *ppos)
330{
331 struct regmap_range_node *range = file->private_data;
332 struct regmap *map = range->map;
333
334 return regmap_read_debugfs(map, range->range_min, range->range_max,
335 user_buf, count, ppos);
336}
337
338static const struct file_operations regmap_range_fops = {
339 .open = simple_open,
340 .read = regmap_range_read_file,
341 .llseek = default_llseek,
342};
343
344static ssize_t regmap_reg_ranges_read_file(struct file *file,
345 char __user *user_buf, size_t count,
346 loff_t *ppos)
347{
348 struct regmap *map = file->private_data;
349 struct regmap_debugfs_off_cache *c;
350 loff_t p = 0;
351 size_t buf_pos = 0;
352 char *buf;
353 char *entry;
354 int ret;
355 unsigned entry_len;
356
357 if (*ppos < 0 || !count)
358 return -EINVAL;
359
360 buf = kmalloc(count, GFP_KERNEL);
361 if (!buf)
362 return -ENOMEM;
363
364 entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
365 if (!entry) {
366 kfree(buf);
367 return -ENOMEM;
368 }
369
370 /* While we are at it, build the register dump cache
371 * now so the read() operation on the `registers' file
372 * can benefit from using the cache. We do not care
373 * about the file position information that is contained
374 * in the cache, just about the actual register blocks */
375 regmap_calc_tot_len(map, buf, count);
376 regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
377
378 /* Reset file pointer as the fixed-format of the `registers'
379 * file is not compatible with the `range' file */
380 p = 0;
381 mutex_lock(&map->cache_lock);
382 list_for_each_entry(c, &map->debugfs_off_cache, list) {
383 entry_len = snprintf(entry, PAGE_SIZE, "%x-%x\n",
384 c->base_reg, c->max_reg);
385 if (p >= *ppos) {
386 if (buf_pos + entry_len > count)
387 break;
388 memcpy(buf + buf_pos, entry, entry_len);
389 buf_pos += entry_len;
390 }
391 p += entry_len;
392 }
393 mutex_unlock(&map->cache_lock);
394
395 kfree(entry);
396 ret = buf_pos;
397
398 if (copy_to_user(user_buf, buf, buf_pos)) {
399 ret = -EFAULT;
400 goto out_buf;
401 }
402
403 *ppos += buf_pos;
404out_buf:
405 kfree(buf);
406 return ret;
407}
408
409static const struct file_operations regmap_reg_ranges_fops = {
410 .open = simple_open,
411 .read = regmap_reg_ranges_read_file,
412 .llseek = default_llseek,
413};
414
415static int regmap_access_show(struct seq_file *s, void *ignored)
416{
417 struct regmap *map = s->private;
418 int i, reg_len;
419
420 reg_len = regmap_calc_reg_len(map->max_register);
421
422 for (i = 0; i <= map->max_register; i += map->reg_stride) {
423 /* Ignore registers which are neither readable nor writable */
424 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
425 continue;
426
427 /* Format the register */
428 seq_printf(s, "%.*x: %c %c %c %c\n", reg_len, i,
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');
433 }
434
435 return 0;
436}
437
438static int access_open(struct inode *inode, struct file *file)
439{
440 return single_open(file, regmap_access_show, inode->i_private);
441}
442
443static const struct file_operations regmap_access_fops = {
444 .open = access_open,
445 .read = seq_read,
446 .llseek = seq_lseek,
447 .release = single_release,
448};
449
450static ssize_t regmap_cache_only_write_file(struct file *file,
451 const char __user *user_buf,
452 size_t count, loff_t *ppos)
453{
454 struct regmap *map = container_of(file->private_data,
455 struct regmap, cache_only);
456 ssize_t result;
457 bool was_enabled, require_sync = false;
458 int err;
459
460 map->lock(map->lock_arg);
461
462 was_enabled = map->cache_only;
463
464 result = debugfs_write_file_bool(file, user_buf, count, ppos);
465 if (result < 0) {
466 map->unlock(map->lock_arg);
467 return result;
468 }
469
470 if (map->cache_only && !was_enabled) {
471 dev_warn(map->dev, "debugfs cache_only=Y forced\n");
472 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
473 } else if (!map->cache_only && was_enabled) {
474 dev_warn(map->dev, "debugfs cache_only=N forced: syncing cache\n");
475 require_sync = true;
476 }
477
478 map->unlock(map->lock_arg);
479
480 if (require_sync) {
481 err = regcache_sync(map);
482 if (err)
483 dev_err(map->dev, "Failed to sync cache %d\n", err);
484 }
485
486 return result;
487}
488
489static const struct file_operations regmap_cache_only_fops = {
490 .open = simple_open,
491 .read = debugfs_read_file_bool,
492 .write = regmap_cache_only_write_file,
493};
494
495static ssize_t regmap_cache_bypass_write_file(struct file *file,
496 const char __user *user_buf,
497 size_t count, loff_t *ppos)
498{
499 struct regmap *map = container_of(file->private_data,
500 struct regmap, cache_bypass);
501 ssize_t result;
502 bool was_enabled;
503
504 map->lock(map->lock_arg);
505
506 was_enabled = map->cache_bypass;
507
508 result = debugfs_write_file_bool(file, user_buf, count, ppos);
509 if (result < 0)
510 goto out;
511
512 if (map->cache_bypass && !was_enabled) {
513 dev_warn(map->dev, "debugfs cache_bypass=Y forced\n");
514 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
515 } else if (!map->cache_bypass && was_enabled) {
516 dev_warn(map->dev, "debugfs cache_bypass=N forced\n");
517 }
518
519out:
520 map->unlock(map->lock_arg);
521
522 return result;
523}
524
525static const struct file_operations regmap_cache_bypass_fops = {
526 .open = simple_open,
527 .read = debugfs_read_file_bool,
528 .write = regmap_cache_bypass_write_file,
529};
530
531void regmap_debugfs_init(struct regmap *map, const char *name)
532{
533 struct rb_node *next;
534 struct regmap_range_node *range_node;
535 const char *devname = "dummy";
536
537 /*
538 * Userspace can initiate reads from the hardware over debugfs.
539 * Normally internal regmap structures and buffers are protected with
540 * a mutex or a spinlock, but if the regmap owner decided to disable
541 * all locking mechanisms, this is no longer the case. For safety:
542 * don't create the debugfs entries if locking is disabled.
543 */
544 if (map->debugfs_disable) {
545 dev_dbg(map->dev, "regmap locking disabled - not creating debugfs entries\n");
546 return;
547 }
548
549 /* If we don't have the debugfs root yet, postpone init */
550 if (!regmap_debugfs_root) {
551 struct regmap_debugfs_node *node;
552 node = kzalloc(sizeof(*node), GFP_KERNEL);
553 if (!node)
554 return;
555 node->map = map;
556 node->name = name;
557 mutex_lock(®map_debugfs_early_lock);
558 list_add(&node->link, ®map_debugfs_early_list);
559 mutex_unlock(®map_debugfs_early_lock);
560 return;
561 }
562
563 INIT_LIST_HEAD(&map->debugfs_off_cache);
564 mutex_init(&map->cache_lock);
565
566 if (map->dev)
567 devname = dev_name(map->dev);
568
569 if (name) {
570 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
571 devname, name);
572 name = map->debugfs_name;
573 } else {
574 name = devname;
575 }
576
577 if (!strcmp(name, "dummy")) {
578 map->debugfs_name = kasprintf(GFP_KERNEL, "dummy%d",
579 dummy_index);
580 name = map->debugfs_name;
581 dummy_index++;
582 }
583
584 map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
585 if (!map->debugfs) {
586 dev_warn(map->dev,
587 "Failed to create %s debugfs directory\n", name);
588
589 kfree(map->debugfs_name);
590 map->debugfs_name = NULL;
591 return;
592 }
593
594 debugfs_create_file("name", 0400, map->debugfs,
595 map, ®map_name_fops);
596
597 debugfs_create_file("range", 0400, map->debugfs,
598 map, ®map_reg_ranges_fops);
599
600 if (map->max_register || regmap_readable(map, 0)) {
601 umode_t registers_mode;
602
603#if defined(REGMAP_ALLOW_WRITE_DEBUGFS)
604 registers_mode = 0600;
605#else
606 registers_mode = 0400;
607#endif
608
609 debugfs_create_file("registers", registers_mode, map->debugfs,
610 map, ®map_map_fops);
611 debugfs_create_file("access", 0400, map->debugfs,
612 map, ®map_access_fops);
613 }
614
615 if (map->cache_type) {
616 debugfs_create_file("cache_only", 0600, map->debugfs,
617 &map->cache_only, ®map_cache_only_fops);
618 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
619 &map->cache_dirty);
620 debugfs_create_file("cache_bypass", 0600, map->debugfs,
621 &map->cache_bypass,
622 ®map_cache_bypass_fops);
623 }
624
625 next = rb_first(&map->range_tree);
626 while (next) {
627 range_node = rb_entry(next, struct regmap_range_node, node);
628
629 if (range_node->name)
630 debugfs_create_file(range_node->name, 0400,
631 map->debugfs, range_node,
632 ®map_range_fops);
633
634 next = rb_next(&range_node->node);
635 }
636
637 if (map->cache_ops && map->cache_ops->debugfs_init)
638 map->cache_ops->debugfs_init(map);
639}
640
641void regmap_debugfs_exit(struct regmap *map)
642{
643 if (map->debugfs) {
644 debugfs_remove_recursive(map->debugfs);
645 mutex_lock(&map->cache_lock);
646 regmap_debugfs_free_dump_cache(map);
647 mutex_unlock(&map->cache_lock);
648 kfree(map->debugfs_name);
649 } else {
650 struct regmap_debugfs_node *node, *tmp;
651
652 mutex_lock(®map_debugfs_early_lock);
653 list_for_each_entry_safe(node, tmp, ®map_debugfs_early_list,
654 link) {
655 if (node->map == map) {
656 list_del(&node->link);
657 kfree(node);
658 }
659 }
660 mutex_unlock(®map_debugfs_early_lock);
661 }
662}
663
664void regmap_debugfs_initcall(void)
665{
666 struct regmap_debugfs_node *node, *tmp;
667
668 regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
669 if (!regmap_debugfs_root) {
670 pr_warn("regmap: Failed to create debugfs root\n");
671 return;
672 }
673
674 mutex_lock(®map_debugfs_early_lock);
675 list_for_each_entry_safe(node, tmp, ®map_debugfs_early_list, link) {
676 regmap_debugfs_init(node->map, node->name);
677 list_del(&node->link);
678 kfree(node);
679 }
680 mutex_unlock(®map_debugfs_early_lock);
681}