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 /*
  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                 map->debugfs_val_len = 2 * map->format.val_bytes;
 178                 map->debugfs_tot_len = map->debugfs_reg_len +
 179                         map->debugfs_val_len + 3;      /* : \n */
 180         }
 181 }
 182
 183 static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
 184                                    unsigned int to, char __user *user_buf,
 185                                    size_t count, loff_t *ppos)
 186 {
 187         size_t buf_pos = 0;
 188         loff_t p = *ppos;
 189         ssize_t ret;
 190         int i;
 191         char *buf;
 192         unsigned int val, start_reg;
 193
 194         if (*ppos < 0 || !count)
 195                 return -EINVAL;
 196
 197         if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
 198                 count = PAGE_SIZE << (MAX_ORDER - 1);
 199
 200         buf = kmalloc(count, GFP_KERNEL);
 201         if (!buf)
 202                 return -ENOMEM;
 203
 204         regmap_calc_tot_len(map, buf, count);
 205
 206         /* Work out which register we're starting at */
 207         start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
 208
 209         for (i = start_reg; i <= to; i += map->reg_stride) {
 210                 if (!regmap_readable(map, i))
 211                         continue;
 212
 213                 if (regmap_precious(map, i))
 214                         continue;
 215
 216                 /* If we're in the region the user is trying to read */
 217                 if (p >= *ppos) {
 218                         /* ...but not beyond it */
 219                         if (buf_pos + map->debugfs_tot_len > count)
 220                                 break;
 221
 222                         /* Format the register */
 223                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
 224                                  map->debugfs_reg_len, i - from);
 225                         buf_pos += map->debugfs_reg_len + 2;
 226
 227                         /* Format the value, write all X if we can't read */
 228                         ret = regmap_read(map, i, &val);
 229                         if (ret == 0)
 230                                 snprintf(buf + buf_pos, count - buf_pos,
 231                                          "%.*x", map->debugfs_val_len, val);
 232                         else
 233                                 memset(buf + buf_pos, 'X',
 234                                        map->debugfs_val_len);
 235                         buf_pos += 2 * map->format.val_bytes;
 236
 237                         buf[buf_pos++] = '\n';
 238                 }
 239                 p += map->debugfs_tot_len;
 240         }
 241
 242         ret = buf_pos;
 243
 244         if (copy_to_user(user_buf, buf, buf_pos)) {
 245                 ret = -EFAULT;
 246                 goto out;
 247         }
 248
 249         *ppos += buf_pos;
 250
 251 out:
 252         kfree(buf);
 253         return ret;
 254 }
 255
 256 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 257                                     size_t count, loff_t *ppos)
 258 {
 259         struct regmap *map = file->private_data;
 260
 261         return regmap_read_debugfs(map, 0, map->max_register, user_buf,
 262                                    count, ppos);
 263 }
 264
 265 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 266 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 267 /*
 268  * This can be dangerous especially when we have clients such as
 269  * PMICs, therefore don't provide any real compile time configuration option
 270  * for this feature, people who want to use this will need to modify
 271  * the source code directly.
 272  */
 273 static ssize_t regmap_map_write_file(struct file *file,
 274                                      const char __user *user_buf,
 275                                      size_t count, loff_t *ppos)
 276 {
 277         char buf[32];
 278         size_t buf_size;
 279         char *start = buf;
 280         unsigned long reg, value;
 281         struct regmap *map = file->private_data;
 282         int ret;
 283
 284         buf_size = min(count, (sizeof(buf)-1));
 285         if (copy_from_user(buf, user_buf, buf_size))
 286                 return -EFAULT;
 287         buf[buf_size] = 0;
 288
 289         while (*start == ' ')
 290                 start++;
 291         reg = simple_strtoul(start, &start, 16);
 292         while (*start == ' ')
 293                 start++;
 294         if (kstrtoul(start, 16, &value))
 295                 return -EINVAL;
 296
 297         /* Userspace has been fiddling around behind the kernel's back */
 298         add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 299
 300         ret = regmap_write(map, reg, value);
 301         if (ret < 0)
 302                 return ret;
 303         return buf_size;
 304 }
 305 #else
 306 #define regmap_map_write_file NULL
 307 #endif
 308
 309 static const struct file_operations regmap_map_fops = {
 310         .open = simple_open,
 311         .read = regmap_map_read_file,
 312         .write = regmap_map_write_file,
 313         .llseek = default_llseek,
 314 };
 315
 316 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
 317                                       size_t count, loff_t *ppos)
 318 {
 319         struct regmap_range_node *range = file->private_data;
 320         struct regmap *map = range->map;
 321
 322         return regmap_read_debugfs(map, range->range_min, range->range_max,
 323                                    user_buf, count, ppos);
 324 }
 325
 326 static const struct file_operations regmap_range_fops = {
 327         .open = simple_open,
 328         .read = regmap_range_read_file,
 329         .llseek = default_llseek,
 330 };
 331
 332 static ssize_t regmap_reg_ranges_read_file(struct file *file,
 333                                            char __user *user_buf, size_t count,
 334                                            loff_t *ppos)
 335 {
 336         struct regmap *map = file->private_data;
 337         struct regmap_debugfs_off_cache *c;
 338         loff_t p = 0;
 339         size_t buf_pos = 0;
 340         char *buf;
 341         char *entry;
 342         int ret;
 343         unsigned entry_len;
 344
 345         if (*ppos < 0 || !count)
 346                 return -EINVAL;
 347
 348         if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
 349                 count = PAGE_SIZE << (MAX_ORDER - 1);
 350
 351         buf = kmalloc(count, GFP_KERNEL);
 352         if (!buf)
 353                 return -ENOMEM;
 354
 355         entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
 356         if (!entry) {
 357                 kfree(buf);
 358                 return -ENOMEM;
 359         }
 360
 361         /* While we are at it, build the register dump cache
 362          * now so the read() operation on the `registers' file
 363          * can benefit from using the cache.  We do not care
 364          * about the file position information that is contained
 365          * in the cache, just about the actual register blocks */
 366         regmap_calc_tot_len(map, buf, count);
 367         regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
 368
 369         /* Reset file pointer as the fixed-format of the `registers'
 370          * file is not compatible with the `range' file */
 371         p = 0;
 372         mutex_lock(&map->cache_lock);
 373         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 374                 entry_len = snprintf(entry, PAGE_SIZE, "%x-%x\n",
 375                                      c->base_reg, c->max_reg);
 376                 if (p >= *ppos) {
 377                         if (buf_pos + entry_len > count)
 378                                 break;
 379                         memcpy(buf + buf_pos, entry, entry_len);
 380                         buf_pos += entry_len;
 381                 }
 382                 p += entry_len;
 383         }
 384         mutex_unlock(&map->cache_lock);
 385
 386         kfree(entry);
 387         ret = buf_pos;
 388
 389         if (copy_to_user(user_buf, buf, buf_pos)) {
 390                 ret = -EFAULT;
 391                 goto out_buf;
 392         }
 393
 394         *ppos += buf_pos;
 395 out_buf:
 396         kfree(buf);
 397         return ret;
 398 }
 399
 400 static const struct file_operations regmap_reg_ranges_fops = {
 401         .open = simple_open,
 402         .read = regmap_reg_ranges_read_file,
 403         .llseek = default_llseek,
 404 };
 405
 406 static ssize_t regmap_access_read_file(struct file *file,
 407                                        char __user *user_buf, size_t count,
 408                                        loff_t *ppos)
 409 {
 410         int reg_len, tot_len;
 411         size_t buf_pos = 0;
 412         loff_t p = 0;
 413         ssize_t ret;
 414         int i;
 415         struct regmap *map = file->private_data;
 416         char *buf;
 417
 418         if (*ppos < 0 || !count)
 419                 return -EINVAL;
 420
 421         buf = kmalloc(count, GFP_KERNEL);
 422         if (!buf)
 423                 return -ENOMEM;
 424
 425         /* Calculate the length of a fixed format  */
 426         reg_len = regmap_calc_reg_len(map->max_register);
 427         tot_len = reg_len + 10; /* ': R W V P\n' */
 428
 429         for (i = 0; i <= map->max_register; i += map->reg_stride) {
 430                 /* Ignore registers which are neither readable nor writable */
 431                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 432                         continue;
 433
 434                 /* If we're in the region the user is trying to read */
 435                 if (p >= *ppos) {
 436                         /* ...but not beyond it */
 437                         if (buf_pos + tot_len + 1 >= count)
 438                                 break;
 439
 440                         /* Format the register */
 441                         snprintf(buf + buf_pos, count - buf_pos,
 442                                  "%.*x: %c %c %c %c\n",
 443                                  reg_len, i,
 444                                  regmap_readable(map, i) ? 'y' : 'n',
 445                                  regmap_writeable(map, i) ? 'y' : 'n',
 446                                  regmap_volatile(map, i) ? 'y' : 'n',
 447                                  regmap_precious(map, i) ? 'y' : 'n');
 448
 449                         buf_pos += tot_len;
 450                 }
 451                 p += tot_len;
 452         }
 453
 454         ret = buf_pos;
 455
 456         if (copy_to_user(user_buf, buf, buf_pos)) {
 457                 ret = -EFAULT;
 458                 goto out;
 459         }
 460
 461         *ppos += buf_pos;
 462
 463 out:
 464         kfree(buf);
 465         return ret;
 466 }
 467
 468 static const struct file_operations regmap_access_fops = {
 469         .open = simple_open,
 470         .read = regmap_access_read_file,
 471         .llseek = default_llseek,
 472 };
 473
 474 static ssize_t regmap_cache_only_write_file(struct file *file,
 475                                             const char __user *user_buf,
 476                                             size_t count, loff_t *ppos)
 477 {
 478         struct regmap *map = container_of(file->private_data,
 479                                           struct regmap, cache_only);
 480         ssize_t result;
 481         bool was_enabled, require_sync = false;
 482         int err;
 483
 484         map->lock(map->lock_arg);
 485
 486         was_enabled = map->cache_only;
 487
 488         result = debugfs_write_file_bool(file, user_buf, count, ppos);
 489         if (result < 0) {
 490                 map->unlock(map->lock_arg);
 491                 return result;
 492         }
 493
 494         if (map->cache_only && !was_enabled) {
 495                 dev_warn(map->dev, "debugfs cache_only=Y forced\n");
 496                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 497         } else if (!map->cache_only && was_enabled) {
 498                 dev_warn(map->dev, "debugfs cache_only=N forced: syncing cache\n");
 499                 require_sync = true;
 500         }
 501
 502         map->unlock(map->lock_arg);
 503
 504         if (require_sync) {
 505                 err = regcache_sync(map);
 506                 if (err)
 507                         dev_err(map->dev, "Failed to sync cache %d\n", err);
 508         }
 509
 510         return result;
 511 }
 512
 513 static const struct file_operations regmap_cache_only_fops = {
 514         .open = simple_open,
 515         .read = debugfs_read_file_bool,
 516         .write = regmap_cache_only_write_file,
 517 };
 518
 519 static ssize_t regmap_cache_bypass_write_file(struct file *file,
 520                                               const char __user *user_buf,
 521                                               size_t count, loff_t *ppos)
 522 {
 523         struct regmap *map = container_of(file->private_data,
 524                                           struct regmap, cache_bypass);
 525         ssize_t result;
 526         bool was_enabled;
 527
 528         map->lock(map->lock_arg);
 529
 530         was_enabled = map->cache_bypass;
 531
 532         result = debugfs_write_file_bool(file, user_buf, count, ppos);
 533         if (result < 0)
 534                 goto out;
 535
 536         if (map->cache_bypass && !was_enabled) {
 537                 dev_warn(map->dev, "debugfs cache_bypass=Y forced\n");
 538                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 539         } else if (!map->cache_bypass && was_enabled) {
 540                 dev_warn(map->dev, "debugfs cache_bypass=N forced\n");
 541         }
 542
 543 out:
 544         map->unlock(map->lock_arg);
 545
 546         return result;
 547 }
 548
 549 static const struct file_operations regmap_cache_bypass_fops = {
 550         .open = simple_open,
 551         .read = debugfs_read_file_bool,
 552         .write = regmap_cache_bypass_write_file,
 553 };
 554
 555 void regmap_debugfs_init(struct regmap *map, const char *name)
 556 {
 557         struct rb_node *next;
 558         struct regmap_range_node *range_node;
 559         const char *devname = "dummy";
 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                 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 583                                               devname, name);
 584                 name = map->debugfs_name;
 585         } else {
 586                 name = devname;
 587         }
 588
 589         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 590         if (!map->debugfs) {
 591                 dev_warn(map->dev, "Failed to create debugfs directory\n");
 592                 return;
 593         }
 594
 595         debugfs_create_file("name", 0400, map->debugfs,
 596                             map, &regmap_name_fops);
 597
 598         debugfs_create_file("range", 0400, map->debugfs,
 599                             map, &regmap_reg_ranges_fops);
 600
 601         if (map->max_register || regmap_readable(map, 0)) {
 602                 umode_t registers_mode;
 603
 604 #if defined(REGMAP_ALLOW_WRITE_DEBUGFS)
 605                 registers_mode = 0600;
 606 #else
 607                 registers_mode = 0400;
 608 #endif
 609
 610                 debugfs_create_file("registers", registers_mode, map->debugfs,
 611                                     map, &regmap_map_fops);
 612                 debugfs_create_file("access", 0400, map->debugfs,
 613                                     map, &regmap_access_fops);
 614         }
 615
 616         if (map->cache_type) {
 617                 debugfs_create_file("cache_only", 0600, map->debugfs,
 618                                     &map->cache_only, &regmap_cache_only_fops);
 619                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 620                                     &map->cache_dirty);
 621                 debugfs_create_file("cache_bypass", 0600, map->debugfs,
 622                                     &map->cache_bypass,
 623                                     &regmap_cache_bypass_fops);
 624         }
 625
 626         next = rb_first(&map->range_tree);
 627         while (next) {
 628                 range_node = rb_entry(next, struct regmap_range_node, node);
 629
 630                 if (range_node->name)
 631                         debugfs_create_file(range_node->name, 0400,
 632                                             map->debugfs, range_node,
 633                                             &regmap_range_fops);
 634
 635                 next = rb_next(&range_node->node);
 636         }
 637
 638         if (map->cache_ops && map->cache_ops->debugfs_init)
 639                 map->cache_ops->debugfs_init(map);
 640 }
 641
 642 void regmap_debugfs_exit(struct regmap *map)
 643 {
 644         if (map->debugfs) {
 645                 debugfs_remove_recursive(map->debugfs);
 646                 mutex_lock(&map->cache_lock);
 647                 regmap_debugfs_free_dump_cache(map);
 648                 mutex_unlock(&map->cache_lock);
 649                 kfree(map->debugfs_name);
 650         } else {
 651                 struct regmap_debugfs_node *node, *tmp;
 652
 653                 mutex_lock(&regmap_debugfs_early_lock);
 654                 list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list,
 655                                          link) {
 656                         if (node->map == map) {
 657                                 list_del(&node->link);
 658                                 kfree(node);
 659                         }
 660                 }
 661                 mutex_unlock(&regmap_debugfs_early_lock);
 662         }
 663 }
 664
 665 void regmap_debugfs_initcall(void)
 666 {
 667         struct regmap_debugfs_node *node, *tmp;
 668
 669         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 670         if (!regmap_debugfs_root) {
 671                 pr_warn("regmap: Failed to create debugfs root\n");
 672                 return;
 673         }
 674
 675         mutex_lock(&regmap_debugfs_early_lock);
 676         list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list, link) {
 677                 regmap_debugfs_init(node->map, node->name);
 678                 list_del(&node->link);
 679                 kfree(node);
 680         }
 681         mutex_unlock(&regmap_debugfs_early_lock);
 682 }