blob: 7d0c83b47259e6a0b079670c02707e2bf6907a89 [file] [log] [blame]
rjw1f884582022-01-06 17:20:42 +08001/*
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 if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
208 count = PAGE_SIZE << (MAX_ORDER - 1);
209
210 buf = kmalloc(count, GFP_KERNEL);
211 if (!buf)
212 return -ENOMEM;
213
214 regmap_calc_tot_len(map, buf, count);
215
216 /* Work out which register we're starting at */
217 start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
218
219 for (i = start_reg; i <= to; i += map->reg_stride) {
220 if (!regmap_readable(map, i) && !regmap_cached(map, i))
221 continue;
222
223 if (regmap_precious(map, i))
224 continue;
225
226 /* If we're in the region the user is trying to read */
227 if (p >= *ppos) {
228 /* ...but not beyond it */
229 if (buf_pos + map->debugfs_tot_len > count)
230 break;
231
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;
236
237 /* Format the value, write all X if we can't read */
238 ret = regmap_read(map, i, &val);
239 if (ret == 0)
240 snprintf(buf + buf_pos, count - buf_pos,
241 "%.*x", map->debugfs_val_len, val);
242 else
243 memset(buf + buf_pos, 'X',
244 map->debugfs_val_len);
245 buf_pos += 2 * map->format.val_bytes;
246
247 buf[buf_pos++] = '\n';
248 }
249 p += map->debugfs_tot_len;
250 }
251
252 ret = buf_pos;
253
254 if (copy_to_user(user_buf, buf, buf_pos)) {
255 ret = -EFAULT;
256 goto out;
257 }
258
259 *ppos += buf_pos;
260
261out:
262 kfree(buf);
263 return ret;
264}
265
266static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
267 size_t count, loff_t *ppos)
268{
269 struct regmap *map = file->private_data;
270
271 return regmap_read_debugfs(map, 0, map->max_register, user_buf,
272 count, ppos);
273}
274
275#undef REGMAP_ALLOW_WRITE_DEBUGFS
276#ifdef REGMAP_ALLOW_WRITE_DEBUGFS
277/*
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.
282 */
283static ssize_t regmap_map_write_file(struct file *file,
284 const char __user *user_buf,
285 size_t count, loff_t *ppos)
286{
287 char buf[32];
288 size_t buf_size;
289 char *start = buf;
290 unsigned long reg, value;
291 struct regmap *map = file->private_data;
292 int ret;
293
294 buf_size = min(count, (sizeof(buf)-1));
295 if (copy_from_user(buf, user_buf, buf_size))
296 return -EFAULT;
297 buf[buf_size] = 0;
298
299 while (*start == ' ')
300 start++;
301 reg = simple_strtoul(start, &start, 16);
302 while (*start == ' ')
303 start++;
304 if (kstrtoul(start, 16, &value))
305 return -EINVAL;
306
307 /* Userspace has been fiddling around behind the kernel's back */
308 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
309
310 ret = regmap_write(map, reg, value);
311 if (ret < 0)
312 return ret;
313 return buf_size;
314}
315#else
316#define regmap_map_write_file NULL
317#endif
318
319static const struct file_operations regmap_map_fops = {
320 .open = simple_open,
321 .read = regmap_map_read_file,
322 .write = regmap_map_write_file,
323 .llseek = default_llseek,
324};
325
326static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
327 size_t count, loff_t *ppos)
328{
329 struct regmap_range_node *range = file->private_data;
330 struct regmap *map = range->map;
331
332 return regmap_read_debugfs(map, range->range_min, range->range_max,
333 user_buf, count, ppos);
334}
335
336static const struct file_operations regmap_range_fops = {
337 .open = simple_open,
338 .read = regmap_range_read_file,
339 .llseek = default_llseek,
340};
341
342static ssize_t regmap_reg_ranges_read_file(struct file *file,
343 char __user *user_buf, size_t count,
344 loff_t *ppos)
345{
346 struct regmap *map = file->private_data;
347 struct regmap_debugfs_off_cache *c;
348 loff_t p = 0;
349 size_t buf_pos = 0;
350 char *buf;
351 char *entry;
352 int ret;
353 unsigned entry_len;
354
355 if (*ppos < 0 || !count)
356 return -EINVAL;
357
358 if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
359 count = PAGE_SIZE << (MAX_ORDER - 1);
360
361 buf = kmalloc(count, GFP_KERNEL);
362 if (!buf)
363 return -ENOMEM;
364
365 entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
366 if (!entry) {
367 kfree(buf);
368 return -ENOMEM;
369 }
370
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);
378
379 /* Reset file pointer as the fixed-format of the `registers'
380 * file is not compatible with the `range' file */
381 p = 0;
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);
386 if (p >= *ppos) {
387 if (buf_pos + entry_len > count)
388 break;
389 memcpy(buf + buf_pos, entry, entry_len);
390 buf_pos += entry_len;
391 }
392 p += entry_len;
393 }
394 mutex_unlock(&map->cache_lock);
395
396 kfree(entry);
397 ret = buf_pos;
398
399 if (copy_to_user(user_buf, buf, buf_pos)) {
400 ret = -EFAULT;
401 goto out_buf;
402 }
403
404 *ppos += buf_pos;
405out_buf:
406 kfree(buf);
407 return ret;
408}
409
410static const struct file_operations regmap_reg_ranges_fops = {
411 .open = simple_open,
412 .read = regmap_reg_ranges_read_file,
413 .llseek = default_llseek,
414};
415
416static int regmap_access_show(struct seq_file *s, void *ignored)
417{
418 struct regmap *map = s->private;
419 int i, reg_len;
420
421 reg_len = regmap_calc_reg_len(map->max_register);
422
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))
426 continue;
427
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');
434 }
435
436 return 0;
437}
438
439static int access_open(struct inode *inode, struct file *file)
440{
441 return single_open(file, regmap_access_show, inode->i_private);
442}
443
444static const struct file_operations regmap_access_fops = {
445 .open = access_open,
446 .read = seq_read,
447 .llseek = seq_lseek,
448 .release = single_release,
449};
450
451static ssize_t regmap_cache_only_write_file(struct file *file,
452 const char __user *user_buf,
453 size_t count, loff_t *ppos)
454{
455 struct regmap *map = container_of(file->private_data,
456 struct regmap, cache_only);
457 ssize_t result;
458 bool was_enabled, require_sync = false;
459 int err;
460
461 map->lock(map->lock_arg);
462
463 was_enabled = map->cache_only;
464
465 result = debugfs_write_file_bool(file, user_buf, count, ppos);
466 if (result < 0) {
467 map->unlock(map->lock_arg);
468 return result;
469 }
470
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");
476 require_sync = true;
477 }
478
479 map->unlock(map->lock_arg);
480
481 if (require_sync) {
482 err = regcache_sync(map);
483 if (err)
484 dev_err(map->dev, "Failed to sync cache %d\n", err);
485 }
486
487 return result;
488}
489
490static const struct file_operations regmap_cache_only_fops = {
491 .open = simple_open,
492 .read = debugfs_read_file_bool,
493 .write = regmap_cache_only_write_file,
494};
495
496static ssize_t regmap_cache_bypass_write_file(struct file *file,
497 const char __user *user_buf,
498 size_t count, loff_t *ppos)
499{
500 struct regmap *map = container_of(file->private_data,
501 struct regmap, cache_bypass);
502 ssize_t result;
503 bool was_enabled;
504
505 map->lock(map->lock_arg);
506
507 was_enabled = map->cache_bypass;
508
509 result = debugfs_write_file_bool(file, user_buf, count, ppos);
510 if (result < 0)
511 goto out;
512
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");
518 }
519
520out:
521 map->unlock(map->lock_arg);
522
523 return result;
524}
525
526static const struct file_operations regmap_cache_bypass_fops = {
527 .open = simple_open,
528 .read = debugfs_read_file_bool,
529 .write = regmap_cache_bypass_write_file,
530};
531
532void regmap_debugfs_init(struct regmap *map, const char *name)
533{
534 struct rb_node *next;
535 struct regmap_range_node *range_node;
536 const char *devname = "dummy";
537
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);
542 if (!node)
543 return;
544 node->map = map;
545 node->name = name;
546 mutex_lock(&regmap_debugfs_early_lock);
547 list_add(&node->link, &regmap_debugfs_early_list);
548 mutex_unlock(&regmap_debugfs_early_lock);
549 return;
550 }
551
552 INIT_LIST_HEAD(&map->debugfs_off_cache);
553 mutex_init(&map->cache_lock);
554
555 if (map->dev)
556 devname = dev_name(map->dev);
557
558 if (name) {
559 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
560 devname, name);
561 name = map->debugfs_name;
562 } else {
563 name = devname;
564 }
565
566 map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
567 if (!map->debugfs) {
568 dev_warn(map->dev, "Failed to create debugfs directory\n");
569 return;
570 }
571
572 debugfs_create_file("name", 0400, map->debugfs,
573 map, &regmap_name_fops);
574
575 debugfs_create_file("range", 0400, map->debugfs,
576 map, &regmap_reg_ranges_fops);
577
578 if (map->max_register || regmap_readable(map, 0)) {
579 umode_t registers_mode;
580
581#if defined(REGMAP_ALLOW_WRITE_DEBUGFS)
582 registers_mode = 0600;
583#else
584 registers_mode = 0400;
585#endif
586
587 debugfs_create_file("registers", registers_mode, map->debugfs,
588 map, &regmap_map_fops);
589 debugfs_create_file("access", 0400, map->debugfs,
590 map, &regmap_access_fops);
591 }
592
593 if (map->cache_type) {
594 debugfs_create_file("cache_only", 0600, map->debugfs,
595 &map->cache_only, &regmap_cache_only_fops);
596 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
597 &map->cache_dirty);
598 debugfs_create_file("cache_bypass", 0600, map->debugfs,
599 &map->cache_bypass,
600 &regmap_cache_bypass_fops);
601 }
602
603 next = rb_first(&map->range_tree);
604 while (next) {
605 range_node = rb_entry(next, struct regmap_range_node, node);
606
607 if (range_node->name)
608 debugfs_create_file(range_node->name, 0400,
609 map->debugfs, range_node,
610 &regmap_range_fops);
611
612 next = rb_next(&range_node->node);
613 }
614
615 if (map->cache_ops && map->cache_ops->debugfs_init)
616 map->cache_ops->debugfs_init(map);
617}
618
619void regmap_debugfs_exit(struct regmap *map)
620{
621 if (map->debugfs) {
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);
627 } else {
628 struct regmap_debugfs_node *node, *tmp;
629
630 mutex_lock(&regmap_debugfs_early_lock);
631 list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list,
632 link) {
633 if (node->map == map) {
634 list_del(&node->link);
635 kfree(node);
636 }
637 }
638 mutex_unlock(&regmap_debugfs_early_lock);
639 }
640}
641
642void regmap_debugfs_initcall(void)
643{
644 struct regmap_debugfs_node *node, *tmp;
645
646 regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
647 if (!regmap_debugfs_root) {
648 pr_warn("regmap: Failed to create debugfs root\n");
649 return;
650 }
651
652 mutex_lock(&regmap_debugfs_early_lock);
653 list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list, link) {
654 regmap_debugfs_init(node->map, node->name);
655 list_del(&node->link);
656 kfree(node);
657 }
658 mutex_unlock(&regmap_debugfs_early_lock);
659}