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