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)
  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 static 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  */
  95 static 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
 181 static 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
 193 static 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
 261 out:
 262         kfree(buf);
 263         return ret;
 264 }
 265
 266 static 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  */
 283 static 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
 319 static 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
 326 static 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
 336 static const struct file_operations regmap_range_fops = {
 337         .open = simple_open,
 338         .read = regmap_range_read_file,
 339         .llseek = default_llseek,
 340 };
 341
 342 static 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;
 405 out_buf:
 406         kfree(buf);
 407         return ret;
 408 }
 409
 410 static 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
 416 static 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
 439 static int access_open(struct inode *inode, struct file *file)
 440 {
 441         return single_open(file, regmap_access_show, inode->i_private);
 442 }
 443
 444 static 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
 451 static 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
 490 static 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
 496 static 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
 520 out:
 521         map->unlock(map->lock_arg);
 522
 523         return result;
 524 }
 525
 526 static 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
 532 void 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
 619 void 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
 642 void 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 }