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         buf = kmalloc(count, GFP_KERNEL);
 198         if (!buf)
 199                 return -ENOMEM;
 200
 201         regmap_calc_tot_len(map, buf, count);
 202
 203         /* Work out which register we're starting at */
 204         start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
 205
 206         for (i = start_reg; i <= to; i += map->reg_stride) {
 207                 if (!regmap_readable(map, i))
 208                         continue;
 209
 210                 if (regmap_precious(map, i))
 211                         continue;
 212
 213                 /* If we're in the region the user is trying to read */
 214                 if (p >= *ppos) {
 215                         /* ...but not beyond it */
 216                         if (buf_pos + map->debugfs_tot_len > count)
 217                                 break;
 218
 219                         /* Format the register */
 220                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
 221                                  map->debugfs_reg_len, i - from);
 222                         buf_pos += map->debugfs_reg_len + 2;
 223
 224                         /* Format the value, write all X if we can't read */
 225                         ret = regmap_read(map, i, &val);
 226                         if (ret == 0)
 227                                 snprintf(buf + buf_pos, count - buf_pos,
 228                                          "%.*x", map->debugfs_val_len, val);
 229                         else
 230                                 memset(buf + buf_pos, 'X',
 231                                        map->debugfs_val_len);
 232                         buf_pos += 2 * map->format.val_bytes;
 233
 234                         buf[buf_pos++] = '\n';
 235                 }
 236                 p += map->debugfs_tot_len;
 237         }
 238
 239         ret = buf_pos;
 240
 241         if (copy_to_user(user_buf, buf, buf_pos)) {
 242                 ret = -EFAULT;
 243                 goto out;
 244         }
 245
 246         *ppos += buf_pos;
 247
 248 out:
 249         kfree(buf);
 250         return ret;
 251 }
 252
 253 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 254                                     size_t count, loff_t *ppos)
 255 {
 256         struct regmap *map = file->private_data;
 257
 258         return regmap_read_debugfs(map, 0, map->max_register, user_buf,
 259                                    count, ppos);
 260 }
 261
 262 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 263 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 264 /*
 265  * This can be dangerous especially when we have clients such as
 266  * PMICs, therefore don't provide any real compile time configuration option
 267  * for this feature, people who want to use this will need to modify
 268  * the source code directly.
 269  */
 270 static ssize_t regmap_map_write_file(struct file *file,
 271                                      const char __user *user_buf,
 272                                      size_t count, loff_t *ppos)
 273 {
 274         char buf[32];
 275         size_t buf_size;
 276         char *start = buf;
 277         unsigned long reg, value;
 278         struct regmap *map = file->private_data;
 279         int ret;
 280
 281         buf_size = min(count, (sizeof(buf)-1));
 282         if (copy_from_user(buf, user_buf, buf_size))
 283                 return -EFAULT;
 284         buf[buf_size] = 0;
 285
 286         while (*start == ' ')
 287                 start++;
 288         reg = simple_strtoul(start, &start, 16);
 289         while (*start == ' ')
 290                 start++;
 291         if (kstrtoul(start, 16, &value))
 292                 return -EINVAL;
 293
 294         /* Userspace has been fiddling around behind the kernel's back */
 295         add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 296
 297         ret = regmap_write(map, reg, value);
 298         if (ret < 0)
 299                 return ret;
 300         return buf_size;
 301 }
 302 #else
 303 #define regmap_map_write_file NULL
 304 #endif
 305
 306 static const struct file_operations regmap_map_fops = {
 307         .open = simple_open,
 308         .read = regmap_map_read_file,
 309         .write = regmap_map_write_file,
 310         .llseek = default_llseek,
 311 };
 312
 313 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
 314                                       size_t count, loff_t *ppos)
 315 {
 316         struct regmap_range_node *range = file->private_data;
 317         struct regmap *map = range->map;
 318
 319         return regmap_read_debugfs(map, range->range_min, range->range_max,
 320                                    user_buf, count, ppos);
 321 }
 322
 323 static const struct file_operations regmap_range_fops = {
 324         .open = simple_open,
 325         .read = regmap_range_read_file,
 326         .llseek = default_llseek,
 327 };
 328
 329 static ssize_t regmap_reg_ranges_read_file(struct file *file,
 330                                            char __user *user_buf, size_t count,
 331                                            loff_t *ppos)
 332 {
 333         struct regmap *map = file->private_data;
 334         struct regmap_debugfs_off_cache *c;
 335         loff_t p = 0;
 336         size_t buf_pos = 0;
 337         char *buf;
 338         char *entry;
 339         int ret;
 340         unsigned entry_len;
 341
 342         if (*ppos < 0 || !count)
 343                 return -EINVAL;
 344
 345         buf = kmalloc(count, GFP_KERNEL);
 346         if (!buf)
 347                 return -ENOMEM;
 348
 349         entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
 350         if (!entry) {
 351                 kfree(buf);
 352                 return -ENOMEM;
 353         }
 354
 355         /* While we are at it, build the register dump cache
 356          * now so the read() operation on the `registers' file
 357          * can benefit from using the cache.  We do not care
 358          * about the file position information that is contained
 359          * in the cache, just about the actual register blocks */
 360         regmap_calc_tot_len(map, buf, count);
 361         regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
 362
 363         /* Reset file pointer as the fixed-format of the `registers'
 364          * file is not compatible with the `range' file */
 365         p = 0;
 366         mutex_lock(&map->cache_lock);
 367         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 368                 entry_len = snprintf(entry, PAGE_SIZE, "%x-%x\n",
 369                                      c->base_reg, c->max_reg);
 370                 if (p >= *ppos) {
 371                         if (buf_pos + entry_len > count)
 372                                 break;
 373                         memcpy(buf + buf_pos, entry, entry_len);
 374                         buf_pos += entry_len;
 375                 }
 376                 p += entry_len;
 377         }
 378         mutex_unlock(&map->cache_lock);
 379
 380         kfree(entry);
 381         ret = buf_pos;
 382
 383         if (copy_to_user(user_buf, buf, buf_pos)) {
 384                 ret = -EFAULT;
 385                 goto out_buf;
 386         }
 387
 388         *ppos += buf_pos;
 389 out_buf:
 390         kfree(buf);
 391         return ret;
 392 }
 393
 394 static const struct file_operations regmap_reg_ranges_fops = {
 395         .open = simple_open,
 396         .read = regmap_reg_ranges_read_file,
 397         .llseek = default_llseek,
 398 };
 399
 400 static int regmap_access_show(struct seq_file *s, void *ignored)
 401 {
 402         struct regmap *map = s->private;
 403         int i, reg_len;
 404
 405         reg_len = regmap_calc_reg_len(map->max_register);
 406
 407         for (i = 0; i <= map->max_register; i += map->reg_stride) {
 408                 /* Ignore registers which are neither readable nor writable */
 409                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 410                         continue;
 411
 412                 /* Format the register */
 413                 seq_printf(s, "%.*x: %c %c %c %c\n", reg_len, i,
 414                            regmap_readable(map, i) ? 'y' : 'n',
 415                            regmap_writeable(map, i) ? 'y' : 'n',
 416                            regmap_volatile(map, i) ? 'y' : 'n',
 417                            regmap_precious(map, i) ? 'y' : 'n');
 418         }
 419
 420         return 0;
 421 }
 422
 423 static int access_open(struct inode *inode, struct file *file)
 424 {
 425         return single_open(file, regmap_access_show, inode->i_private);
 426 }
 427
 428 static const struct file_operations regmap_access_fops = {
 429         .open           = access_open,
 430         .read           = seq_read,
 431         .llseek         = seq_lseek,
 432         .release        = single_release,
 433 };
 434
 435 static ssize_t regmap_cache_only_write_file(struct file *file,
 436                                             const char __user *user_buf,
 437                                             size_t count, loff_t *ppos)
 438 {
 439         struct regmap *map = container_of(file->private_data,
 440                                           struct regmap, cache_only);
 441         ssize_t result;
 442         bool was_enabled, require_sync = false;
 443         int err;
 444
 445         map->lock(map->lock_arg);
 446
 447         was_enabled = map->cache_only;
 448
 449         result = debugfs_write_file_bool(file, user_buf, count, ppos);
 450         if (result < 0) {
 451                 map->unlock(map->lock_arg);
 452                 return result;
 453         }
 454
 455         if (map->cache_only && !was_enabled) {
 456                 dev_warn(map->dev, "debugfs cache_only=Y forced\n");
 457                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 458         } else if (!map->cache_only && was_enabled) {
 459                 dev_warn(map->dev, "debugfs cache_only=N forced: syncing cache\n");
 460                 require_sync = true;
 461         }
 462
 463         map->unlock(map->lock_arg);
 464
 465         if (require_sync) {
 466                 err = regcache_sync(map);
 467                 if (err)
 468                         dev_err(map->dev, "Failed to sync cache %d\n", err);
 469         }
 470
 471         return result;
 472 }
 473
 474 static const struct file_operations regmap_cache_only_fops = {
 475         .open = simple_open,
 476         .read = debugfs_read_file_bool,
 477         .write = regmap_cache_only_write_file,
 478 };
 479
 480 static ssize_t regmap_cache_bypass_write_file(struct file *file,
 481                                               const char __user *user_buf,
 482                                               size_t count, loff_t *ppos)
 483 {
 484         struct regmap *map = container_of(file->private_data,
 485                                           struct regmap, cache_bypass);
 486         ssize_t result;
 487         bool was_enabled;
 488
 489         map->lock(map->lock_arg);
 490
 491         was_enabled = map->cache_bypass;
 492
 493         result = debugfs_write_file_bool(file, user_buf, count, ppos);
 494         if (result < 0)
 495                 goto out;
 496
 497         if (map->cache_bypass && !was_enabled) {
 498                 dev_warn(map->dev, "debugfs cache_bypass=Y forced\n");
 499                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 500         } else if (!map->cache_bypass && was_enabled) {
 501                 dev_warn(map->dev, "debugfs cache_bypass=N forced\n");
 502         }
 503
 504 out:
 505         map->unlock(map->lock_arg);
 506
 507         return result;
 508 }
 509
 510 static const struct file_operations regmap_cache_bypass_fops = {
 511         .open = simple_open,
 512         .read = debugfs_read_file_bool,
 513         .write = regmap_cache_bypass_write_file,
 514 };
 515
 516 void regmap_debugfs_init(struct regmap *map, const char *name)
 517 {
 518         struct rb_node *next;
 519         struct regmap_range_node *range_node;
 520         const char *devname = "dummy";
 521
 522         /* If we don't have the debugfs root yet, postpone init */
 523         if (!regmap_debugfs_root) {
 524                 struct regmap_debugfs_node *node;
 525                 node = kzalloc(sizeof(*node), GFP_KERNEL);
 526                 if (!node)
 527                         return;
 528                 node->map = map;
 529                 node->name = name;
 530                 mutex_lock(&regmap_debugfs_early_lock);
 531                 list_add(&node->link, &regmap_debugfs_early_list);
 532                 mutex_unlock(&regmap_debugfs_early_lock);
 533                 return;
 534         }
 535
 536         INIT_LIST_HEAD(&map->debugfs_off_cache);
 537         mutex_init(&map->cache_lock);
 538
 539         if (map->dev)
 540                 devname = dev_name(map->dev);
 541
 542         if (name) {
 543                 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 544                                               devname, name);
 545                 name = map->debugfs_name;
 546         } else {
 547                 name = devname;
 548         }
 549
 550         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 551         if (!map->debugfs) {
 552                 dev_warn(map->dev, "Failed to create debugfs directory\n");
 553                 return;
 554         }
 555
 556         debugfs_create_file("name", 0400, map->debugfs,
 557                             map, &regmap_name_fops);
 558
 559         debugfs_create_file("range", 0400, map->debugfs,
 560                             map, &regmap_reg_ranges_fops);
 561
 562         if (map->max_register || regmap_readable(map, 0)) {
 563                 umode_t registers_mode;
 564
 565 #if defined(REGMAP_ALLOW_WRITE_DEBUGFS)
 566                 registers_mode = 0600;
 567 #else
 568                 registers_mode = 0400;
 569 #endif
 570
 571                 debugfs_create_file("registers", registers_mode, map->debugfs,
 572                                     map, &regmap_map_fops);
 573                 debugfs_create_file("access", 0400, map->debugfs,
 574                                     map, &regmap_access_fops);
 575         }
 576
 577         if (map->cache_type) {
 578                 debugfs_create_file("cache_only", 0600, map->debugfs,
 579                                     &map->cache_only, &regmap_cache_only_fops);
 580                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 581                                     &map->cache_dirty);
 582                 debugfs_create_file("cache_bypass", 0600, map->debugfs,
 583                                     &map->cache_bypass,
 584                                     &regmap_cache_bypass_fops);
 585         }
 586
 587         next = rb_first(&map->range_tree);
 588         while (next) {
 589                 range_node = rb_entry(next, struct regmap_range_node, node);
 590
 591                 if (range_node->name)
 592                         debugfs_create_file(range_node->name, 0400,
 593                                             map->debugfs, range_node,
 594                                             &regmap_range_fops);
 595
 596                 next = rb_next(&range_node->node);
 597         }
 598
 599         if (map->cache_ops && map->cache_ops->debugfs_init)
 600                 map->cache_ops->debugfs_init(map);
 601 }
 602
 603 void regmap_debugfs_exit(struct regmap *map)
 604 {
 605         if (map->debugfs) {
 606                 debugfs_remove_recursive(map->debugfs);
 607                 mutex_lock(&map->cache_lock);
 608                 regmap_debugfs_free_dump_cache(map);
 609                 mutex_unlock(&map->cache_lock);
 610                 kfree(map->debugfs_name);
 611         } else {
 612                 struct regmap_debugfs_node *node, *tmp;
 613
 614                 mutex_lock(&regmap_debugfs_early_lock);
 615                 list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list,
 616                                          link) {
 617                         if (node->map == map) {
 618                                 list_del(&node->link);
 619                                 kfree(node);
 620                         }
 621                 }
 622                 mutex_unlock(&regmap_debugfs_early_lock);
 623         }
 624 }
 625
 626 void regmap_debugfs_initcall(void)
 627 {
 628         struct regmap_debugfs_node *node, *tmp;
 629
 630         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 631         if (!regmap_debugfs_root) {
 632                 pr_warn("regmap: Failed to create debugfs root\n");
 633                 return;
 634         }
 635
 636         mutex_lock(&regmap_debugfs_early_lock);
 637         list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list, link) {
 638                 regmap_debugfs_init(node->map, node->name);
 639                 list_del(&node->link);
 640                 kfree(node);
 641         }
 642         mutex_unlock(&regmap_debugfs_early_lock);
 643 }