drivers/base/regmap/regmap-debugfs.c

   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
  22 struct regmap_debugfs_node {
  23         struct regmap *map;
  24         const char *name;
  25         struct list_head link;
  26 };
  27
  28 static struct dentry *regmap_debugfs_root;
  29 static LIST_HEAD(regmap_debugfs_early_list);
  30 static DEFINE_MUTEX(regmap_debugfs_early_lock);
  31
  32 /* Calculate the length of a fixed format  */
  33 static size_t regmap_calc_reg_len(int max_val, char *buf, size_t buf_size)
  34 {
  35         return snprintf(NULL, 0, "%x", max_val);
  36 }
  37
  38 static 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
  61 static const struct file_operations regmap_name_fops = {
  62         .open = simple_open,
  63         .read = regmap_name_read_file,
  64         .llseek = default_llseek,
  65 };
  66
  67 static 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
  80 /*
  81  * Work out where the start offset maps into register numbers, bearing
  82  * in mind that we suppress hidden registers.
  83  */
  84 static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
  85                                                   unsigned int base,
  86                                                   loff_t from,
  87                                                   loff_t *pos)
  88 {
  89         struct regmap_debugfs_off_cache *c = NULL;
  90         loff_t p = 0;
  91         unsigned int i, ret;
  92         unsigned int fpos_offset;
  93         unsigned int reg_offset;
  94
  95         /* Suppress the cache if we're using a subrange */
  96         if (base)
  97                 return base;
  98
  99         /*
 100          * If we don't have a cache build one so we don't have to do a
 101          * linear scan each time.
 102          */
 103         mutex_lock(&map->cache_lock);
 104         i = base;
 105         if (list_empty(&map->debugfs_off_cache)) {
 106                 for (; i <= map->max_register; i += map->reg_stride) {
 107                         /* Skip unprinted registers, closing off cache entry */
 108                         if (!regmap_readable(map, i) ||
 109                             regmap_precious(map, i)) {
 110                                 if (c) {
 111                                         c->max = p - 1;
 112                                         c->max_reg = i - map->reg_stride;
 113                                         list_add_tail(&c->list,
 114                                                       &map->debugfs_off_cache);
 115                                         c = NULL;
 116                                 }
 117
 118                                 continue;
 119                         }
 120
 121                         /* No cache entry?  Start a new one */
 122                         if (!c) {
 123                                 c = kzalloc(sizeof(*c), GFP_KERNEL);
 124                                 if (!c) {
 125                                         regmap_debugfs_free_dump_cache(map);
 126                                         mutex_unlock(&map->cache_lock);
 127                                         return base;
 128                                 }
 129                                 c->min = p;
 130                                 c->base_reg = i;
 131                         }
 132
 133                         p += map->debugfs_tot_len;
 134                 }
 135         }
 136
 137         /* Close the last entry off if we didn't scan beyond it */
 138         if (c) {
 139                 c->max = p - 1;
 140                 c->max_reg = i - map->reg_stride;
 141                 list_add_tail(&c->list,
 142                               &map->debugfs_off_cache);
 143         }
 144
 145         /*
 146          * This should never happen; we return above if we fail to
 147          * allocate and we should never be in this code if there are
 148          * no registers at all.
 149          */
 150         WARN_ON(list_empty(&map->debugfs_off_cache));
 151         ret = base;
 152
 153         /* Find the relevant block:offset */
 154         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 155                 if (from >= c->min && from <= c->max) {
 156                         fpos_offset = from - c->min;
 157                         reg_offset = fpos_offset / map->debugfs_tot_len;
 158                         *pos = c->min + (reg_offset * map->debugfs_tot_len);
 159                         mutex_unlock(&map->cache_lock);
 160                         return c->base_reg + (reg_offset * map->reg_stride);
 161                 }
 162
 163                 *pos = c->max;
 164                 ret = c->max_reg;
 165         }
 166         mutex_unlock(&map->cache_lock);
 167
 168         return ret;
 169 }
 170
 171 static inline void regmap_calc_tot_len(struct regmap *map,
 172                                        void *buf, size_t count)
 173 {
 174         /* Calculate the length of a fixed format  */
 175         if (!map->debugfs_tot_len) {
 176                 map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
 177                                                            buf, count);
 178                 map->debugfs_val_len = 2 * map->format.val_bytes;
 179                 map->debugfs_tot_len = map->debugfs_reg_len +
 180                         map->debugfs_val_len + 3;      /* : \n */
 181         }
 182 }
 183
 184 static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
 185                                    unsigned int to, char __user *user_buf,
 186                                    size_t count, loff_t *ppos)
 187 {
 188         size_t buf_pos = 0;
 189         loff_t p = *ppos;
 190         ssize_t ret;
 191         int i;
 192         char *buf;
 193         unsigned int val, start_reg;
 194
 195         if (*ppos < 0 || !count)
 196                 return -EINVAL;
 197
 198         buf = kmalloc(count, GFP_KERNEL);
 199         if (!buf)
 200                 return -ENOMEM;
 201
 202         regmap_calc_tot_len(map, buf, count);
 203
 204         /* Work out which register we're starting at */
 205         start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
 206
 207         for (i = start_reg; i <= to; i += map->reg_stride) {
 208                 if (!regmap_readable(map, i))
 209                         continue;
 210
 211                 if (regmap_precious(map, i))
 212                         continue;
 213
 214                 /* If we're in the region the user is trying to read */
 215                 if (p >= *ppos) {
 216                         /* ...but not beyond it */
 217                         if (buf_pos + map->debugfs_tot_len > count)
 218                                 break;
 219
 220                         /* Format the register */
 221                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
 222                                  map->debugfs_reg_len, i - from);
 223                         buf_pos += map->debugfs_reg_len + 2;
 224
 225                         /* Format the value, write all X if we can't read */
 226                         ret = regmap_read(map, i, &val);
 227                         if (ret == 0)
 228                                 snprintf(buf + buf_pos, count - buf_pos,
 229                                          "%.*x", map->debugfs_val_len, val);
 230                         else
 231                                 memset(buf + buf_pos, 'X',
 232                                        map->debugfs_val_len);
 233                         buf_pos += 2 * map->format.val_bytes;
 234
 235                         buf[buf_pos++] = '\n';
 236                 }
 237                 p += map->debugfs_tot_len;
 238         }
 239
 240         ret = buf_pos;
 241
 242         if (copy_to_user(user_buf, buf, buf_pos)) {
 243                 ret = -EFAULT;
 244                 goto out;
 245         }
 246
 247         *ppos += buf_pos;
 248
 249 out:
 250         kfree(buf);
 251         return ret;
 252 }
 253
 254 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 255                                     size_t count, loff_t *ppos)
 256 {
 257         struct regmap *map = file->private_data;
 258
 259         return regmap_read_debugfs(map, 0, map->max_register, user_buf,
 260                                    count, ppos);
 261 }
 262
 263 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 264 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 265 /*
 266  * This can be dangerous especially when we have clients such as
 267  * PMICs, therefore don't provide any real compile time configuration option
 268  * for this feature, people who want to use this will need to modify
 269  * the source code directly.
 270  */
 271 static ssize_t regmap_map_write_file(struct file *file,
 272                                      const char __user *user_buf,
 273                                      size_t count, loff_t *ppos)
 274 {
 275         char buf[32];
 276         size_t buf_size;
 277         char *start = buf;
 278         unsigned long reg, value;
 279         struct regmap *map = file->private_data;
 280         int ret;
 281
 282         buf_size = min(count, (sizeof(buf)-1));
 283         if (copy_from_user(buf, user_buf, buf_size))
 284                 return -EFAULT;
 285         buf[buf_size] = 0;
 286
 287         while (*start == ' ')
 288                 start++;
 289         reg = simple_strtoul(start, &start, 16);
 290         while (*start == ' ')
 291                 start++;
 292         if (kstrtoul(start, 16, &value))
 293                 return -EINVAL;
 294
 295         /* Userspace has been fiddling around behind the kernel's back */
 296         add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 297
 298         ret = regmap_write(map, reg, value);
 299         if (ret < 0)
 300                 return ret;
 301         return buf_size;
 302 }
 303 #else
 304 #define regmap_map_write_file NULL
 305 #endif
 306
 307 static const struct file_operations regmap_map_fops = {
 308         .open = simple_open,
 309         .read = regmap_map_read_file,
 310         .write = regmap_map_write_file,
 311         .llseek = default_llseek,
 312 };
 313
 314 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
 315                                       size_t count, loff_t *ppos)
 316 {
 317         struct regmap_range_node *range = file->private_data;
 318         struct regmap *map = range->map;
 319
 320         return regmap_read_debugfs(map, range->range_min, range->range_max,
 321                                    user_buf, count, ppos);
 322 }
 323
 324 static const struct file_operations regmap_range_fops = {
 325         .open = simple_open,
 326         .read = regmap_range_read_file,
 327         .llseek = default_llseek,
 328 };
 329
 330 static ssize_t regmap_reg_ranges_read_file(struct file *file,
 331                                            char __user *user_buf, size_t count,
 332                                            loff_t *ppos)
 333 {
 334         struct regmap *map = file->private_data;
 335         struct regmap_debugfs_off_cache *c;
 336         loff_t p = 0;
 337         size_t buf_pos = 0;
 338         char *buf;
 339         char *entry;
 340         int ret;
 341
 342         if (*ppos < 0 || !count)
 343                 return -EINVAL;
 344
 345         buf = kmalloc(count, GFP_KERNEL);
 346         if (!buf)
 347                 return -ENOMEM;
 348
 349         entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
 350         if (!entry) {
 351                 kfree(buf);
 352                 return -ENOMEM;
 353         }
 354
 355         /* While we are at it, build the register dump cache
 356          * now so the read() operation on the `registers' file
 357          * can benefit from using the cache.  We do not care
 358          * about the file position information that is contained
 359          * in the cache, just about the actual register blocks */
 360         regmap_calc_tot_len(map, buf, count);
 361         regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
 362
 363         /* Reset file pointer as the fixed-format of the `registers'
 364          * file is not compatible with the `range' file */
 365         p = 0;
 366         mutex_lock(&map->cache_lock);
 367         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 368                 snprintf(entry, PAGE_SIZE, "%x-%x",
 369                          c->base_reg, c->max_reg);
 370                 if (p >= *ppos) {
 371                         if (buf_pos + 1 + strlen(entry) > count)
 372                                 break;
 373                         snprintf(buf + buf_pos, count - buf_pos,
 374                                  "%s", entry);
 375                         buf_pos += strlen(entry);
 376                         buf[buf_pos] = '\n';
 377                         buf_pos++;
 378                 }
 379                 p += strlen(entry) + 1;
 380         }
 381         mutex_unlock(&map->cache_lock);
 382
 383         kfree(entry);
 384         ret = buf_pos;
 385
 386         if (copy_to_user(user_buf, buf, buf_pos)) {
 387                 ret = -EFAULT;
 388                 goto out_buf;
 389         }
 390
 391         *ppos += buf_pos;
 392 out_buf:
 393         kfree(buf);
 394         return ret;
 395 }
 396
 397 static const struct file_operations regmap_reg_ranges_fops = {
 398         .open = simple_open,
 399         .read = regmap_reg_ranges_read_file,
 400         .llseek = default_llseek,
 401 };
 402
 403 static ssize_t regmap_access_read_file(struct file *file,
 404                                        char __user *user_buf, size_t count,
 405                                        loff_t *ppos)
 406 {
 407         int reg_len, tot_len;
 408         size_t buf_pos = 0;
 409         loff_t p = 0;
 410         ssize_t ret;
 411         int i;
 412         struct regmap *map = file->private_data;
 413         char *buf;
 414
 415         if (*ppos < 0 || !count)
 416                 return -EINVAL;
 417
 418         buf = kmalloc(count, GFP_KERNEL);
 419         if (!buf)
 420                 return -ENOMEM;
 421
 422         /* Calculate the length of a fixed format  */
 423         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
 424         tot_len = reg_len + 10; /* ': R W V P\n' */
 425
 426         for (i = 0; i <= map->max_register; i += map->reg_stride) {
 427                 /* Ignore registers which are neither readable nor writable */
 428                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 429                         continue;
 430
 431                 /* If we're in the region the user is trying to read */
 432                 if (p >= *ppos) {
 433                         /* ...but not beyond it */
 434                         if (buf_pos + tot_len + 1 >= count)
 435                                 break;
 436
 437                         /* Format the register */
 438                         snprintf(buf + buf_pos, count - buf_pos,
 439                                  "%.*x: %c %c %c %c\n",
 440                                  reg_len, i,
 441                                  regmap_readable(map, i) ? 'y' : 'n',
 442                                  regmap_writeable(map, i) ? 'y' : 'n',
 443                                  regmap_volatile(map, i) ? 'y' : 'n',
 444                                  regmap_precious(map, i) ? 'y' : 'n');
 445
 446                         buf_pos += tot_len;
 447                 }
 448                 p += tot_len;
 449         }
 450
 451         ret = buf_pos;
 452
 453         if (copy_to_user(user_buf, buf, buf_pos)) {
 454                 ret = -EFAULT;
 455                 goto out;
 456         }
 457
 458         *ppos += buf_pos;
 459
 460 out:
 461         kfree(buf);
 462         return ret;
 463 }
 464
 465 static const struct file_operations regmap_access_fops = {
 466         .open = simple_open,
 467         .read = regmap_access_read_file,
 468         .llseek = default_llseek,
 469 };
 470
 471 static ssize_t regmap_cache_only_write_file(struct file *file,
 472                                             const char __user *user_buf,
 473                                             size_t count, loff_t *ppos)
 474 {
 475         struct regmap *map = container_of(file->private_data,
 476                                           struct regmap, cache_only);
 477         ssize_t result;
 478         bool was_enabled, require_sync = false;
 479         int err;
 480
 481         map->lock(map->lock_arg);
 482
 483         was_enabled = map->cache_only;
 484
 485         result = debugfs_write_file_bool(file, user_buf, count, ppos);
 486         if (result < 0) {
 487                 map->unlock(map->lock_arg);
 488                 return result;
 489         }
 490
 491         if (map->cache_only && !was_enabled) {
 492                 dev_warn(map->dev, "debugfs cache_only=Y forced\n");
 493                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 494         } else if (!map->cache_only && was_enabled) {
 495                 dev_warn(map->dev, "debugfs cache_only=N forced: syncing cache\n");
 496                 require_sync = true;
 497         }
 498
 499         map->unlock(map->lock_arg);
 500
 501         if (require_sync) {
 502                 err = regcache_sync(map);
 503                 if (err)
 504                         dev_err(map->dev, "Failed to sync cache %d\n", err);
 505         }
 506
 507         return result;
 508 }
 509
 510 static const struct file_operations regmap_cache_only_fops = {
 511         .open = simple_open,
 512         .read = debugfs_read_file_bool,
 513         .write = regmap_cache_only_write_file,
 514 };
 515
 516 static ssize_t regmap_cache_bypass_write_file(struct file *file,
 517                                               const char __user *user_buf,
 518                                               size_t count, loff_t *ppos)
 519 {
 520         struct regmap *map = container_of(file->private_data,
 521                                           struct regmap, cache_bypass);
 522         ssize_t result;
 523         bool was_enabled;
 524
 525         map->lock(map->lock_arg);
 526
 527         was_enabled = map->cache_bypass;
 528
 529         result = debugfs_write_file_bool(file, user_buf, count, ppos);
 530         if (result < 0)
 531                 goto out;
 532
 533         if (map->cache_bypass && !was_enabled) {
 534                 dev_warn(map->dev, "debugfs cache_bypass=Y forced\n");
 535                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 536         } else if (!map->cache_bypass && was_enabled) {
 537                 dev_warn(map->dev, "debugfs cache_bypass=N forced\n");
 538         }
 539
 540 out:
 541         map->unlock(map->lock_arg);
 542
 543         return result;
 544 }
 545
 546 static const struct file_operations regmap_cache_bypass_fops = {
 547         .open = simple_open,
 548         .read = debugfs_read_file_bool,
 549         .write = regmap_cache_bypass_write_file,
 550 };
 551
 552 void regmap_debugfs_init(struct regmap *map, const char *name)
 553 {
 554         struct rb_node *next;
 555         struct regmap_range_node *range_node;
 556         const char *devname = "dummy";
 557
 558         /* If we don't have the debugfs root yet, postpone init */
 559         if (!regmap_debugfs_root) {
 560                 struct regmap_debugfs_node *node;
 561                 node = kzalloc(sizeof(*node), GFP_KERNEL);
 562                 if (!node)
 563                         return;
 564                 node->map = map;
 565                 node->name = name;
 566                 mutex_lock(&regmap_debugfs_early_lock);
 567                 list_add(&node->link, &regmap_debugfs_early_list);
 568                 mutex_unlock(&regmap_debugfs_early_lock);
 569                 return;
 570         }
 571
 572         INIT_LIST_HEAD(&map->debugfs_off_cache);
 573         mutex_init(&map->cache_lock);
 574
 575         if (map->dev)
 576                 devname = dev_name(map->dev);
 577
 578         if (name) {
 579                 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 580                                               devname, name);
 581                 name = map->debugfs_name;
 582         } else {
 583                 name = devname;
 584         }
 585
 586         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 587         if (!map->debugfs) {
 588                 dev_warn(map->dev, "Failed to create debugfs directory\n");
 589                 return;
 590         }
 591
 592         debugfs_create_file("name", 0400, map->debugfs,
 593                             map, &regmap_name_fops);
 594
 595         debugfs_create_file("range", 0400, map->debugfs,
 596                             map, &regmap_reg_ranges_fops);
 597
 598         if (map->max_register || regmap_readable(map, 0)) {
 599                 umode_t registers_mode;
 600
 601 #if defined(REGMAP_ALLOW_WRITE_DEBUGFS)
 602                 registers_mode = 0600;
 603 #else
 604                 registers_mode = 0400;
 605 #endif
 606
 607                 debugfs_create_file("registers", registers_mode, map->debugfs,
 608                                     map, &regmap_map_fops);
 609                 debugfs_create_file("access", 0400, map->debugfs,
 610                                     map, &regmap_access_fops);
 611         }
 612
 613         if (map->cache_type) {
 614                 debugfs_create_file("cache_only", 0600, map->debugfs,
 615                                     &map->cache_only, &regmap_cache_only_fops);
 616                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 617                                     &map->cache_dirty);
 618                 debugfs_create_file("cache_bypass", 0600, map->debugfs,
 619                                     &map->cache_bypass,
 620                                     &regmap_cache_bypass_fops);
 621         }
 622
 623         next = rb_first(&map->range_tree);
 624         while (next) {
 625                 range_node = rb_entry(next, struct regmap_range_node, node);
 626
 627                 if (range_node->name)
 628                         debugfs_create_file(range_node->name, 0400,
 629                                             map->debugfs, range_node,
 630                                             &regmap_range_fops);
 631
 632                 next = rb_next(&range_node->node);
 633         }
 634
 635         if (map->cache_ops && map->cache_ops->debugfs_init)
 636                 map->cache_ops->debugfs_init(map);
 637 }
 638
 639 void regmap_debugfs_exit(struct regmap *map)
 640 {
 641         if (map->debugfs) {
 642                 debugfs_remove_recursive(map->debugfs);
 643                 mutex_lock(&map->cache_lock);
 644                 regmap_debugfs_free_dump_cache(map);
 645                 mutex_unlock(&map->cache_lock);
 646                 kfree(map->debugfs_name);
 647         } else {
 648                 struct regmap_debugfs_node *node, *tmp;
 649
 650                 mutex_lock(&regmap_debugfs_early_lock);
 651                 list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list,
 652                                          link) {
 653                         if (node->map == map) {
 654                                 list_del(&node->link);
 655                                 kfree(node);
 656                         }
 657                 }
 658                 mutex_unlock(&regmap_debugfs_early_lock);
 659         }
 660 }
 661
 662 void regmap_debugfs_initcall(void)
 663 {
 664         struct regmap_debugfs_node *node, *tmp;
 665
 666         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 667         if (!regmap_debugfs_root) {
 668                 pr_warn("regmap: Failed to create debugfs root\n");
 669                 return;
 670         }
 671
 672         mutex_lock(&regmap_debugfs_early_lock);
 673         list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list, link) {
 674                 regmap_debugfs_init(node->map, node->name);
 675                 list_del(&node->link);
 676                 kfree(node);
 677         }
 678         mutex_unlock(&regmap_debugfs_early_lock);
 679 }