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 unsigned int dummy_index;
  29 static struct dentry *regmap_debugfs_root;
  30 static LIST_HEAD(regmap_debugfs_early_list);
  31 static DEFINE_MUTEX(regmap_debugfs_early_lock);
  32
  33 /* Calculate the length of a fixed format  */
  34 static size_t regmap_calc_reg_len(int max_val)
  35 {
  36         return snprintf(NULL, 0, "%x", max_val);
  37 }
  38
  39 static 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
  66 static const struct file_operations regmap_name_fops = {
  67         .open = simple_open,
  68         .read = regmap_name_read_file,
  69         .llseek = default_llseek,
  70 };
  71
  72 static 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
  85 static 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  */
 100 static 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
 186 static 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
 198 static 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         if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
 213                 count = PAGE_SIZE << (MAX_ORDER - 1);
 214
 215         buf = kmalloc(count, GFP_KERNEL);
 216         if (!buf)
 217                 return -ENOMEM;
 218
 219         regmap_calc_tot_len(map, buf, count);
 220
 221         /* Work out which register we're starting at */
 222         start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
 223
 224         for (i = start_reg; i <= to; i += map->reg_stride) {
 225                 if (!regmap_readable(map, i) && !regmap_cached(map, i))
 226                         continue;
 227
 228                 if (regmap_precious(map, i))
 229                         continue;
 230
 231                 /* If we're in the region the user is trying to read */
 232                 if (p >= *ppos) {
 233                         /* ...but not beyond it */
 234                         if (buf_pos + map->debugfs_tot_len > count)
 235                                 break;
 236
 237                         /* Format the register */
 238                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
 239                                  map->debugfs_reg_len, i - from);
 240                         buf_pos += map->debugfs_reg_len + 2;
 241
 242                         /* Format the value, write all X if we can't read */
 243                         ret = regmap_read(map, i, &val);
 244                         if (ret == 0)
 245                                 snprintf(buf + buf_pos, count - buf_pos,
 246                                          "%.*x", map->debugfs_val_len, val);
 247                         else
 248                                 memset(buf + buf_pos, 'X',
 249                                        map->debugfs_val_len);
 250                         buf_pos += 2 * map->format.val_bytes;
 251
 252                         buf[buf_pos++] = '\n';
 253                 }
 254                 p += map->debugfs_tot_len;
 255         }
 256
 257         ret = buf_pos;
 258
 259         if (copy_to_user(user_buf, buf, buf_pos)) {
 260                 ret = -EFAULT;
 261                 goto out;
 262         }
 263
 264         *ppos += buf_pos;
 265
 266 out:
 267         kfree(buf);
 268         return ret;
 269 }
 270
 271 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 272                                     size_t count, loff_t *ppos)
 273 {
 274         struct regmap *map = file->private_data;
 275
 276         return regmap_read_debugfs(map, 0, map->max_register, user_buf,
 277                                    count, ppos);
 278 }
 279
 280 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 281 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 282 /*
 283  * This can be dangerous especially when we have clients such as
 284  * PMICs, therefore don't provide any real compile time configuration option
 285  * for this feature, people who want to use this will need to modify
 286  * the source code directly.
 287  */
 288 static ssize_t regmap_map_write_file(struct file *file,
 289                                      const char __user *user_buf,
 290                                      size_t count, loff_t *ppos)
 291 {
 292         char buf[32];
 293         size_t buf_size;
 294         char *start = buf;
 295         unsigned long reg, value;
 296         struct regmap *map = file->private_data;
 297         int ret;
 298
 299         buf_size = min(count, (sizeof(buf)-1));
 300         if (copy_from_user(buf, user_buf, buf_size))
 301                 return -EFAULT;
 302         buf[buf_size] = 0;
 303
 304         while (*start == ' ')
 305                 start++;
 306         reg = simple_strtoul(start, &start, 16);
 307         while (*start == ' ')
 308                 start++;
 309         if (kstrtoul(start, 16, &value))
 310                 return -EINVAL;
 311
 312         /* Userspace has been fiddling around behind the kernel's back */
 313         add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 314
 315         ret = regmap_write(map, reg, value);
 316         if (ret < 0)
 317                 return ret;
 318         return buf_size;
 319 }
 320 #else
 321 #define regmap_map_write_file NULL
 322 #endif
 323
 324 static const struct file_operations regmap_map_fops = {
 325         .open = simple_open,
 326         .read = regmap_map_read_file,
 327         .write = regmap_map_write_file,
 328         .llseek = default_llseek,
 329 };
 330
 331 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
 332                                       size_t count, loff_t *ppos)
 333 {
 334         struct regmap_range_node *range = file->private_data;
 335         struct regmap *map = range->map;
 336
 337         return regmap_read_debugfs(map, range->range_min, range->range_max,
 338                                    user_buf, count, ppos);
 339 }
 340
 341 static const struct file_operations regmap_range_fops = {
 342         .open = simple_open,
 343         .read = regmap_range_read_file,
 344         .llseek = default_llseek,
 345 };
 346
 347 static ssize_t regmap_reg_ranges_read_file(struct file *file,
 348                                            char __user *user_buf, size_t count,
 349                                            loff_t *ppos)
 350 {
 351         struct regmap *map = file->private_data;
 352         struct regmap_debugfs_off_cache *c;
 353         loff_t p = 0;
 354         size_t buf_pos = 0;
 355         char *buf;
 356         char *entry;
 357         int ret;
 358         unsigned entry_len;
 359
 360         if (*ppos < 0 || !count)
 361                 return -EINVAL;
 362
 363         if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
 364                 count = PAGE_SIZE << (MAX_ORDER - 1);
 365
 366         buf = kmalloc(count, GFP_KERNEL);
 367         if (!buf)
 368                 return -ENOMEM;
 369
 370         entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
 371         if (!entry) {
 372                 kfree(buf);
 373                 return -ENOMEM;
 374         }
 375
 376         /* While we are at it, build the register dump cache
 377          * now so the read() operation on the `registers' file
 378          * can benefit from using the cache.  We do not care
 379          * about the file position information that is contained
 380          * in the cache, just about the actual register blocks */
 381         regmap_calc_tot_len(map, buf, count);
 382         regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
 383
 384         /* Reset file pointer as the fixed-format of the `registers'
 385          * file is not compatible with the `range' file */
 386         p = 0;
 387         mutex_lock(&map->cache_lock);
 388         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 389                 entry_len = snprintf(entry, PAGE_SIZE, "%x-%x\n",
 390                                      c->base_reg, c->max_reg);
 391                 if (p >= *ppos) {
 392                         if (buf_pos + entry_len > count)
 393                                 break;
 394                         memcpy(buf + buf_pos, entry, entry_len);
 395                         buf_pos += entry_len;
 396                 }
 397                 p += entry_len;
 398         }
 399         mutex_unlock(&map->cache_lock);
 400
 401         kfree(entry);
 402         ret = buf_pos;
 403
 404         if (copy_to_user(user_buf, buf, buf_pos)) {
 405                 ret = -EFAULT;
 406                 goto out_buf;
 407         }
 408
 409         *ppos += buf_pos;
 410 out_buf:
 411         kfree(buf);
 412         return ret;
 413 }
 414
 415 static const struct file_operations regmap_reg_ranges_fops = {
 416         .open = simple_open,
 417         .read = regmap_reg_ranges_read_file,
 418         .llseek = default_llseek,
 419 };
 420
 421 static int regmap_access_show(struct seq_file *s, void *ignored)
 422 {
 423         struct regmap *map = s->private;
 424         int i, reg_len;
 425
 426         reg_len = regmap_calc_reg_len(map->max_register);
 427
 428         for (i = 0; i <= map->max_register; i += map->reg_stride) {
 429                 /* Ignore registers which are neither readable nor writable */
 430                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 431                         continue;
 432
 433                 /* Format the register */
 434                 seq_printf(s, "%.*x: %c %c %c %c\n", reg_len, i,
 435                            regmap_readable(map, i) ? 'y' : 'n',
 436                            regmap_writeable(map, i) ? 'y' : 'n',
 437                            regmap_volatile(map, i) ? 'y' : 'n',
 438                            regmap_precious(map, i) ? 'y' : 'n');
 439         }
 440
 441         return 0;
 442 }
 443
 444 static int access_open(struct inode *inode, struct file *file)
 445 {
 446         return single_open(file, regmap_access_show, inode->i_private);
 447 }
 448
 449 static const struct file_operations regmap_access_fops = {
 450         .open           = access_open,
 451         .read           = seq_read,
 452         .llseek         = seq_lseek,
 453         .release        = single_release,
 454 };
 455
 456 static ssize_t regmap_cache_only_write_file(struct file *file,
 457                                             const char __user *user_buf,
 458                                             size_t count, loff_t *ppos)
 459 {
 460         struct regmap *map = container_of(file->private_data,
 461                                           struct regmap, cache_only);
 462         bool new_val, require_sync = false;
 463         int err;
 464
 465         err = kstrtobool_from_user(user_buf, count, &new_val);
 466         /* Ignore malforned data like debugfs_write_file_bool() */
 467         if (err)
 468                 return count;
 469
 470         err = debugfs_file_get(file->f_path.dentry);
 471         if (err)
 472                 return err;
 473
 474         map->lock(map->lock_arg);
 475
 476         if (new_val && !map->cache_only) {
 477                 dev_warn(map->dev, "debugfs cache_only=Y forced\n");
 478                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 479         } else if (!new_val && map->cache_only) {
 480                 dev_warn(map->dev, "debugfs cache_only=N forced: syncing cache\n");
 481                 require_sync = true;
 482         }
 483         map->cache_only = new_val;
 484
 485         map->unlock(map->lock_arg);
 486         debugfs_file_put(file->f_path.dentry);
 487
 488         if (require_sync) {
 489                 err = regcache_sync(map);
 490                 if (err)
 491                         dev_err(map->dev, "Failed to sync cache %d\n", err);
 492         }
 493
 494         return count;
 495 }
 496
 497 static const struct file_operations regmap_cache_only_fops = {
 498         .open = simple_open,
 499         .read = debugfs_read_file_bool,
 500         .write = regmap_cache_only_write_file,
 501 };
 502
 503 static ssize_t regmap_cache_bypass_write_file(struct file *file,
 504                                               const char __user *user_buf,
 505                                               size_t count, loff_t *ppos)
 506 {
 507         struct regmap *map = container_of(file->private_data,
 508                                           struct regmap, cache_bypass);
 509         bool new_val;
 510         int err;
 511
 512         err = kstrtobool_from_user(user_buf, count, &new_val);
 513         /* Ignore malforned data like debugfs_write_file_bool() */
 514         if (err)
 515                 return count;
 516
 517         err = debugfs_file_get(file->f_path.dentry);
 518         if (err)
 519                 return err;
 520
 521         map->lock(map->lock_arg);
 522
 523         if (new_val && !map->cache_bypass) {
 524                 dev_warn(map->dev, "debugfs cache_bypass=Y forced\n");
 525                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 526         } else if (!new_val && map->cache_bypass) {
 527                 dev_warn(map->dev, "debugfs cache_bypass=N forced\n");
 528         }
 529         map->cache_bypass = new_val;
 530
 531         map->unlock(map->lock_arg);
 532         debugfs_file_put(file->f_path.dentry);
 533
 534         return count;
 535 }
 536
 537 static const struct file_operations regmap_cache_bypass_fops = {
 538         .open = simple_open,
 539         .read = debugfs_read_file_bool,
 540         .write = regmap_cache_bypass_write_file,
 541 };
 542
 543 void regmap_debugfs_init(struct regmap *map, const char *name)
 544 {
 545         struct rb_node *next;
 546         struct regmap_range_node *range_node;
 547         const char *devname = "dummy";
 548
 549         /*
 550          * Userspace can initiate reads from the hardware over debugfs.
 551          * Normally internal regmap structures and buffers are protected with
 552          * a mutex or a spinlock, but if the regmap owner decided to disable
 553          * all locking mechanisms, this is no longer the case. For safety:
 554          * don't create the debugfs entries if locking is disabled.
 555          */
 556         if (map->debugfs_disable) {
 557                 dev_dbg(map->dev, "regmap locking disabled - not creating debugfs entries\n");
 558                 return;
 559         }
 560
 561         /* If we don't have the debugfs root yet, postpone init */
 562         if (!regmap_debugfs_root) {
 563                 struct regmap_debugfs_node *node;
 564                 node = kzalloc(sizeof(*node), GFP_KERNEL);
 565                 if (!node)
 566                         return;
 567                 node->map = map;
 568                 node->name = name;
 569                 mutex_lock(&regmap_debugfs_early_lock);
 570                 list_add(&node->link, &regmap_debugfs_early_list);
 571                 mutex_unlock(&regmap_debugfs_early_lock);
 572                 return;
 573         }
 574
 575         INIT_LIST_HEAD(&map->debugfs_off_cache);
 576         mutex_init(&map->cache_lock);
 577
 578         if (map->dev)
 579                 devname = dev_name(map->dev);
 580
 581         if (name) {
 582                 if (!map->debugfs_name) {
 583                         map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 584                                               devname, name);
 585                         if (!map->debugfs_name)
 586                                 return;
 587                 }
 588                 name = map->debugfs_name;
 589         } else {
 590                 name = devname;
 591         }
 592
 593         if (!strcmp(name, "dummy")) {
 594                 kfree(map->debugfs_name);
 595                 map->debugfs_name = kasprintf(GFP_KERNEL, "dummy%d",
 596                                                 dummy_index);
 597                 if (!map->debugfs_name)
 598                                 return;
 599                 name = map->debugfs_name;
 600                 dummy_index++;
 601         }
 602
 603         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 604         if (!map->debugfs) {
 605                 dev_warn(map->dev,
 606                          "Failed to create %s debugfs directory\n", name);
 607
 608                 kfree(map->debugfs_name);
 609                 map->debugfs_name = NULL;
 610                 return;
 611         }
 612
 613         debugfs_create_file("name", 0400, map->debugfs,
 614                             map, &regmap_name_fops);
 615
 616         debugfs_create_file("range", 0400, map->debugfs,
 617                             map, &regmap_reg_ranges_fops);
 618
 619         if (map->max_register || regmap_readable(map, 0)) {
 620                 umode_t registers_mode;
 621
 622 #if defined(REGMAP_ALLOW_WRITE_DEBUGFS)
 623                 registers_mode = 0600;
 624 #else
 625                 registers_mode = 0400;
 626 #endif
 627
 628                 debugfs_create_file("registers", registers_mode, map->debugfs,
 629                                     map, &regmap_map_fops);
 630                 debugfs_create_file("access", 0400, map->debugfs,
 631                                     map, &regmap_access_fops);
 632         }
 633
 634         if (map->cache_type) {
 635                 debugfs_create_file("cache_only", 0600, map->debugfs,
 636                                     &map->cache_only, &regmap_cache_only_fops);
 637                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 638                                     &map->cache_dirty);
 639                 debugfs_create_file("cache_bypass", 0600, map->debugfs,
 640                                     &map->cache_bypass,
 641                                     &regmap_cache_bypass_fops);
 642         }
 643
 644         next = rb_first(&map->range_tree);
 645         while (next) {
 646                 range_node = rb_entry(next, struct regmap_range_node, node);
 647
 648                 if (range_node->name)
 649                         debugfs_create_file(range_node->name, 0400,
 650                                             map->debugfs, range_node,
 651                                             &regmap_range_fops);
 652
 653                 next = rb_next(&range_node->node);
 654         }
 655
 656         if (map->cache_ops && map->cache_ops->debugfs_init)
 657                 map->cache_ops->debugfs_init(map);
 658 }
 659
 660 void regmap_debugfs_exit(struct regmap *map)
 661 {
 662         if (map->debugfs) {
 663                 debugfs_remove_recursive(map->debugfs);
 664                 mutex_lock(&map->cache_lock);
 665                 regmap_debugfs_free_dump_cache(map);
 666                 mutex_unlock(&map->cache_lock);
 667                 kfree(map->debugfs_name);
 668                 map->debugfs_name = NULL;
 669         } else {
 670                 struct regmap_debugfs_node *node, *tmp;
 671
 672                 mutex_lock(&regmap_debugfs_early_lock);
 673                 list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list,
 674                                          link) {
 675                         if (node->map == map) {
 676                                 list_del(&node->link);
 677                                 kfree(node);
 678                         }
 679                 }
 680                 mutex_unlock(&regmap_debugfs_early_lock);
 681         }
 682 }
 683
 684 void regmap_debugfs_initcall(void)
 685 {
 686         struct regmap_debugfs_node *node, *tmp;
 687
 688         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 689         if (!regmap_debugfs_root) {
 690                 pr_warn("regmap: Failed to create debugfs root\n");
 691                 return;
 692         }
 693
 694         mutex_lock(&regmap_debugfs_early_lock);
 695         list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list, link) {
 696                 regmap_debugfs_init(node->map, node->name);
 697                 list_del(&node->link);
 698                 kfree(node);
 699         }
 700         mutex_unlock(&regmap_debugfs_early_lock);
 701 }