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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 struct dentry *regmap_debugfs_root;
29static LIST_HEAD(regmap_debugfs_early_list);
30static DEFINE_MUTEX(regmap_debugfs_early_lock);
31
32/* Calculate the length of a fixed format */
33static size_t regmap_calc_reg_len(int max_val)
34{
35 return snprintf(NULL, 0, "%x", max_val);
36}
37
38static ssize_t regmap_name_read_file(struct file *file,
39 char __user *user_buf, size_t count,
40 loff_t *ppos)
41{
42 struct regmap *map = file->private_data;
43 int ret;
44 char *buf;
45
46 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
47 if (!buf)
48 return -ENOMEM;
49
50 ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
51 if (ret < 0) {
52 kfree(buf);
53 return ret;
54 }
55
56 ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
57 kfree(buf);
58 return ret;
59}
60
61static const struct file_operations regmap_name_fops = {
62 .open = simple_open,
63 .read = regmap_name_read_file,
64 .llseek = default_llseek,
65};
66
67static void regmap_debugfs_free_dump_cache(struct regmap *map)
68{
69 struct regmap_debugfs_off_cache *c;
70
71 while (!list_empty(&map->debugfs_off_cache)) {
72 c = list_first_entry(&map->debugfs_off_cache,
73 struct regmap_debugfs_off_cache,
74 list);
75 list_del(&c->list);
76 kfree(c);
77 }
78}
79
80static bool regmap_printable(struct regmap *map, unsigned int reg)
81{
82 if (regmap_precious(map, reg))
83 return false;
84
85 if (!regmap_readable(map, reg) && !regmap_cached(map, reg))
86 return false;
87
88 return true;
89}
90
91/*
92 * Work out where the start offset maps into register numbers, bearing
93 * in mind that we suppress hidden registers.
94 */
95static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
96 unsigned int base,
97 loff_t from,
98 loff_t *pos)
99{
100 struct regmap_debugfs_off_cache *c = NULL;
101 loff_t p = 0;
102 unsigned int i, ret;
103 unsigned int fpos_offset;
104 unsigned int reg_offset;
105
106 /* Suppress the cache if we're using a subrange */
107 if (base)
108 return base;
109
110 /*
111 * If we don't have a cache build one so we don't have to do a
112 * linear scan each time.
113 */
114 mutex_lock(&map->cache_lock);
115 i = base;
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)) {
120 if (c) {
121 c->max = p - 1;
122 c->max_reg = i - map->reg_stride;
123 list_add_tail(&c->list,
124 &map->debugfs_off_cache);
125 c = NULL;
126 }
127
128 continue;
129 }
130
131 /* No cache entry? Start a new one */
132 if (!c) {
133 c = kzalloc(sizeof(*c), GFP_KERNEL);
134 if (!c) {
135 regmap_debugfs_free_dump_cache(map);
136 mutex_unlock(&map->cache_lock);
137 return base;
138 }
139 c->min = p;
140 c->base_reg = i;
141 }
142
143 p += map->debugfs_tot_len;
144 }
145 }
146
147 /* Close the last entry off if we didn't scan beyond it */
148 if (c) {
149 c->max = p - 1;
150 c->max_reg = i - map->reg_stride;
151 list_add_tail(&c->list,
152 &map->debugfs_off_cache);
153 }
154
155 /*
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.
159 */
160 WARN_ON(list_empty(&map->debugfs_off_cache));
161 ret = base;
162
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);
171 }
172
173 *pos = c->max;
174 ret = c->max_reg;
175 }
176 mutex_unlock(&map->cache_lock);
177
178 return ret;
179}
180
181static inline void regmap_calc_tot_len(struct regmap *map,
182 void *buf, size_t count)
183{
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 */
190 }
191}
192
193static 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)
196{
197 size_t buf_pos = 0;
198 loff_t p = *ppos;
199 ssize_t ret;
200 int i;
201 char *buf;
202 unsigned int val, start_reg;
203
204 if (*ppos < 0 || !count)
205 return -EINVAL;
206
207 buf = kmalloc(count, GFP_KERNEL);
208 if (!buf)
209 return -ENOMEM;
210
211 regmap_calc_tot_len(map, buf, count);
212
213 /* Work out which register we're starting at */
214 start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
215
216 for (i = start_reg; i <= to; i += map->reg_stride) {
217 if (!regmap_readable(map, i) && !regmap_cached(map, i))
218 continue;
219
220 if (regmap_precious(map, i))
221 continue;
222
223 /* If we're in the region the user is trying to read */
224 if (p >= *ppos) {
225 /* ...but not beyond it */
226 if (buf_pos + map->debugfs_tot_len > count)
227 break;
228
229 /* Format the register */
230 snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
231 map->debugfs_reg_len, i - from);
232 buf_pos += map->debugfs_reg_len + 2;
233
234 /* Format the value, write all X if we can't read */
235 ret = regmap_read(map, i, &val);
236 if (ret == 0)
237 snprintf(buf + buf_pos, count - buf_pos,
238 "%.*x", map->debugfs_val_len, val);
239 else
240 memset(buf + buf_pos, 'X',
241 map->debugfs_val_len);
242 buf_pos += 2 * map->format.val_bytes;
243
244 buf[buf_pos++] = '\n';
245 }
246 p += map->debugfs_tot_len;
247 }
248
249 ret = buf_pos;
250
251 if (copy_to_user(user_buf, buf, buf_pos)) {
252 ret = -EFAULT;
253 goto out;
254 }
255
256 *ppos += buf_pos;
257
258out:
259 kfree(buf);
260 return ret;
261}
262
263static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
264 size_t count, loff_t *ppos)
265{
266 struct regmap *map = file->private_data;
267
268 return regmap_read_debugfs(map, 0, map->max_register, user_buf,
269 count, ppos);
270}
271
272#undef REGMAP_ALLOW_WRITE_DEBUGFS
273#ifdef REGMAP_ALLOW_WRITE_DEBUGFS
274/*
275 * This can be dangerous especially when we have clients such as
276 * PMICs, therefore don't provide any real compile time configuration option
277 * for this feature, people who want to use this will need to modify
278 * the source code directly.
279 */
280static ssize_t regmap_map_write_file(struct file *file,
281 const char __user *user_buf,
282 size_t count, loff_t *ppos)
283{
284 char buf[32];
285 size_t buf_size;
286 char *start = buf;
287 unsigned long reg, value;
288 struct regmap *map = file->private_data;
289 int ret;
290
291 buf_size = min(count, (sizeof(buf)-1));
292 if (copy_from_user(buf, user_buf, buf_size))
293 return -EFAULT;
294 buf[buf_size] = 0;
295
296 while (*start == ' ')
297 start++;
298 reg = simple_strtoul(start, &start, 16);
299 while (*start == ' ')
300 start++;
301 if (kstrtoul(start, 16, &value))
302 return -EINVAL;
303
304 /* Userspace has been fiddling around behind the kernel's back */
305 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
306
307 ret = regmap_write(map, reg, value);
308 if (ret < 0)
309 return ret;
310 return buf_size;
311}
312#else
313#define regmap_map_write_file NULL
314#endif
315
316static const struct file_operations regmap_map_fops = {
317 .open = simple_open,
318 .read = regmap_map_read_file,
319 .write = regmap_map_write_file,
320 .llseek = default_llseek,
321};
322
323static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
324 size_t count, loff_t *ppos)
325{
326 struct regmap_range_node *range = file->private_data;
327 struct regmap *map = range->map;
328
329 return regmap_read_debugfs(map, range->range_min, range->range_max,
330 user_buf, count, ppos);
331}
332
333static const struct file_operations regmap_range_fops = {
334 .open = simple_open,
335 .read = regmap_range_read_file,
336 .llseek = default_llseek,
337};
338
339static ssize_t regmap_reg_ranges_read_file(struct file *file,
340 char __user *user_buf, size_t count,
341 loff_t *ppos)
342{
343 struct regmap *map = file->private_data;
344 struct regmap_debugfs_off_cache *c;
345 loff_t p = 0;
346 size_t buf_pos = 0;
347 char *buf;
348 char *entry;
349 int ret;
350 unsigned entry_len;
351
352 if (*ppos < 0 || !count)
353 return -EINVAL;
354
355 buf = kmalloc(count, GFP_KERNEL);
356 if (!buf)
357 return -ENOMEM;
358
359 entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
360 if (!entry) {
361 kfree(buf);
362 return -ENOMEM;
363 }
364
365 /* While we are at it, build the register dump cache
366 * now so the read() operation on the `registers' file
367 * can benefit from using the cache. We do not care
368 * about the file position information that is contained
369 * in the cache, just about the actual register blocks */
370 regmap_calc_tot_len(map, buf, count);
371 regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
372
373 /* Reset file pointer as the fixed-format of the `registers'
374 * file is not compatible with the `range' file */
375 p = 0;
376 mutex_lock(&map->cache_lock);
377 list_for_each_entry(c, &map->debugfs_off_cache, list) {
378 entry_len = snprintf(entry, PAGE_SIZE, "%x-%x\n",
379 c->base_reg, c->max_reg);
380 if (p >= *ppos) {
381 if (buf_pos + entry_len > count)
382 break;
383 memcpy(buf + buf_pos, entry, entry_len);
384 buf_pos += entry_len;
385 }
386 p += entry_len;
387 }
388 mutex_unlock(&map->cache_lock);
389
390 kfree(entry);
391 ret = buf_pos;
392
393 if (copy_to_user(user_buf, buf, buf_pos)) {
394 ret = -EFAULT;
395 goto out_buf;
396 }
397
398 *ppos += buf_pos;
399out_buf:
400 kfree(buf);
401 return ret;
402}
403
404static const struct file_operations regmap_reg_ranges_fops = {
405 .open = simple_open,
406 .read = regmap_reg_ranges_read_file,
407 .llseek = default_llseek,
408};
409
410static int regmap_access_show(struct seq_file *s, void *ignored)
411{
412 struct regmap *map = s->private;
413 int i, reg_len;
414
415 reg_len = regmap_calc_reg_len(map->max_register);
416
417 for (i = 0; i <= map->max_register; i += map->reg_stride) {
418 /* Ignore registers which are neither readable nor writable */
419 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
420 continue;
421
422 /* Format the register */
423 seq_printf(s, "%.*x: %c %c %c %c\n", reg_len, i,
424 regmap_readable(map, i) ? 'y' : 'n',
425 regmap_writeable(map, i) ? 'y' : 'n',
426 regmap_volatile(map, i) ? 'y' : 'n',
427 regmap_precious(map, i) ? 'y' : 'n');
428 }
429
430 return 0;
431}
432
433static int access_open(struct inode *inode, struct file *file)
434{
435 return single_open(file, regmap_access_show, inode->i_private);
436}
437
438static const struct file_operations regmap_access_fops = {
439 .open = access_open,
440 .read = seq_read,
441 .llseek = seq_lseek,
442 .release = single_release,
443};
444
445static ssize_t regmap_cache_only_write_file(struct file *file,
446 const char __user *user_buf,
447 size_t count, loff_t *ppos)
448{
449 struct regmap *map = container_of(file->private_data,
450 struct regmap, cache_only);
451 ssize_t result;
452 bool was_enabled, require_sync = false;
453 int err;
454
455 map->lock(map->lock_arg);
456
457 was_enabled = map->cache_only;
458
459 result = debugfs_write_file_bool(file, user_buf, count, ppos);
460 if (result < 0) {
461 map->unlock(map->lock_arg);
462 return result;
463 }
464
465 if (map->cache_only && !was_enabled) {
466 dev_warn(map->dev, "debugfs cache_only=Y forced\n");
467 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
468 } else if (!map->cache_only && was_enabled) {
469 dev_warn(map->dev, "debugfs cache_only=N forced: syncing cache\n");
470 require_sync = true;
471 }
472
473 map->unlock(map->lock_arg);
474
475 if (require_sync) {
476 err = regcache_sync(map);
477 if (err)
478 dev_err(map->dev, "Failed to sync cache %d\n", err);
479 }
480
481 return result;
482}
483
484static const struct file_operations regmap_cache_only_fops = {
485 .open = simple_open,
486 .read = debugfs_read_file_bool,
487 .write = regmap_cache_only_write_file,
488};
489
490static ssize_t regmap_cache_bypass_write_file(struct file *file,
491 const char __user *user_buf,
492 size_t count, loff_t *ppos)
493{
494 struct regmap *map = container_of(file->private_data,
495 struct regmap, cache_bypass);
496 ssize_t result;
497 bool was_enabled;
498
499 map->lock(map->lock_arg);
500
501 was_enabled = map->cache_bypass;
502
503 result = debugfs_write_file_bool(file, user_buf, count, ppos);
504 if (result < 0)
505 goto out;
506
507 if (map->cache_bypass && !was_enabled) {
508 dev_warn(map->dev, "debugfs cache_bypass=Y forced\n");
509 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
510 } else if (!map->cache_bypass && was_enabled) {
511 dev_warn(map->dev, "debugfs cache_bypass=N forced\n");
512 }
513
514out:
515 map->unlock(map->lock_arg);
516
517 return result;
518}
519
520static const struct file_operations regmap_cache_bypass_fops = {
521 .open = simple_open,
522 .read = debugfs_read_file_bool,
523 .write = regmap_cache_bypass_write_file,
524};
525
526void regmap_debugfs_init(struct regmap *map, const char *name)
527{
528 struct rb_node *next;
529 struct regmap_range_node *range_node;
530 const char *devname = "dummy";
531
532 /* If we don't have the debugfs root yet, postpone init */
533 if (!regmap_debugfs_root) {
534 struct regmap_debugfs_node *node;
535 node = kzalloc(sizeof(*node), GFP_KERNEL);
536 if (!node)
537 return;
538 node->map = map;
539 node->name = name;
540 mutex_lock(®map_debugfs_early_lock);
541 list_add(&node->link, ®map_debugfs_early_list);
542 mutex_unlock(®map_debugfs_early_lock);
543 return;
544 }
545
546 INIT_LIST_HEAD(&map->debugfs_off_cache);
547 mutex_init(&map->cache_lock);
548
549 if (map->dev)
550 devname = dev_name(map->dev);
551
552 if (name) {
553 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
554 devname, name);
555 name = map->debugfs_name;
556 } else {
557 name = devname;
558 }
559
560 map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
561 if (!map->debugfs) {
562 dev_warn(map->dev, "Failed to create debugfs directory\n");
563 return;
564 }
565
566 debugfs_create_file("name", 0400, map->debugfs,
567 map, ®map_name_fops);
568
569 debugfs_create_file("range", 0400, map->debugfs,
570 map, ®map_reg_ranges_fops);
571
572 if (map->max_register || regmap_readable(map, 0)) {
573 umode_t registers_mode;
574
575#if defined(REGMAP_ALLOW_WRITE_DEBUGFS)
576 registers_mode = 0600;
577#else
578 registers_mode = 0400;
579#endif
580
581 debugfs_create_file("registers", registers_mode, map->debugfs,
582 map, ®map_map_fops);
583 debugfs_create_file("access", 0400, map->debugfs,
584 map, ®map_access_fops);
585 }
586
587 if (map->cache_type) {
588 debugfs_create_file("cache_only", 0600, map->debugfs,
589 &map->cache_only, ®map_cache_only_fops);
590 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
591 &map->cache_dirty);
592 debugfs_create_file("cache_bypass", 0600, map->debugfs,
593 &map->cache_bypass,
594 ®map_cache_bypass_fops);
595 }
596
597 next = rb_first(&map->range_tree);
598 while (next) {
599 range_node = rb_entry(next, struct regmap_range_node, node);
600
601 if (range_node->name)
602 debugfs_create_file(range_node->name, 0400,
603 map->debugfs, range_node,
604 ®map_range_fops);
605
606 next = rb_next(&range_node->node);
607 }
608
609 if (map->cache_ops && map->cache_ops->debugfs_init)
610 map->cache_ops->debugfs_init(map);
611}
612
613void regmap_debugfs_exit(struct regmap *map)
614{
615 if (map->debugfs) {
616 debugfs_remove_recursive(map->debugfs);
617 mutex_lock(&map->cache_lock);
618 regmap_debugfs_free_dump_cache(map);
619 mutex_unlock(&map->cache_lock);
620 kfree(map->debugfs_name);
621 } else {
622 struct regmap_debugfs_node *node, *tmp;
623
624 mutex_lock(®map_debugfs_early_lock);
625 list_for_each_entry_safe(node, tmp, ®map_debugfs_early_list,
626 link) {
627 if (node->map == map) {
628 list_del(&node->link);
629 kfree(node);
630 }
631 }
632 mutex_unlock(®map_debugfs_early_lock);
633 }
634}
635
636void regmap_debugfs_initcall(void)
637{
638 struct regmap_debugfs_node *node, *tmp;
639
640 regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
641 if (!regmap_debugfs_root) {
642 pr_warn("regmap: Failed to create debugfs root\n");
643 return;
644 }
645
646 mutex_lock(®map_debugfs_early_lock);
647 list_for_each_entry_safe(node, tmp, ®map_debugfs_early_list, link) {
648 regmap_debugfs_init(node->map, node->name);
649 list_del(&node->link);
650 kfree(node);
651 }
652 mutex_unlock(®map_debugfs_early_lock);
653}