kernel/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, char *buf, size_t buf_size)
  34 {
  35         snprintf(buf, buf_size, "%x", max_val);
  36         return strlen(buf);
  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         int ret;
  45         char *buf;
  46
  47         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
  48         if (!buf)
  49                 return -ENOMEM;
  50
  51         ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
  52         if (ret < 0) {
  53                 kfree(buf);
  54                 return ret;
  55         }
  56
  57         ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
  58         kfree(buf);
  59         return ret;
  60 }
  61
  62 static const struct file_operations regmap_name_fops = {
  63         .open = simple_open,
  64         .read = regmap_name_read_file,
  65         .llseek = default_llseek,
  66 };
  67
  68 static void regmap_debugfs_free_dump_cache(struct regmap *map)
  69 {
  70         struct regmap_debugfs_off_cache *c;
  71
  72         while (!list_empty(&map->debugfs_off_cache)) {
  73                 c = list_first_entry(&map->debugfs_off_cache,
  74                                      struct regmap_debugfs_off_cache,
  75                                      list);
  76                 list_del(&c->list);
  77                 kfree(c);
  78         }
  79 }
  80
  81 /*
  82  * Work out where the start offset maps into register numbers, bearing
  83  * in mind that we suppress hidden registers.
  84  */
  85 static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
  86                                                   unsigned int base,
  87                                                   loff_t from,
  88                                                   loff_t *pos)
  89 {
  90         struct regmap_debugfs_off_cache *c = NULL;
  91         loff_t p = 0;
  92         unsigned int i, ret;
  93         unsigned int fpos_offset;
  94         unsigned int reg_offset;
  95
  96         /* Suppress the cache if we're using a subrange */
  97         if (base)
  98                 return base;
  99
 100         /*
 101          * If we don't have a cache build one so we don't have to do a
 102          * linear scan each time.
 103          */
 104         mutex_lock(&map->cache_lock);
 105         i = base;
 106         if (list_empty(&map->debugfs_off_cache)) {
 107                 for (; i <= map->max_register; i += map->reg_stride) {
 108                         /* Skip unprinted registers, closing off cache entry */
 109                         if (!regmap_readable(map, i) ||
 110                             regmap_precious(map, i)) {
 111                                 if (c) {
 112                                         c->max = p - 1;
 113                                         c->max_reg = i - map->reg_stride;
 114                                         list_add_tail(&c->list,
 115                                                       &map->debugfs_off_cache);
 116                                         c = NULL;
 117                                 }
 118
 119                                 continue;
 120                         }
 121
 122                         /* No cache entry?  Start a new one */
 123                         if (!c) {
 124                                 c = kzalloc(sizeof(*c), GFP_KERNEL);
 125                                 if (!c) {
 126                                         regmap_debugfs_free_dump_cache(map);
 127                                         mutex_unlock(&map->cache_lock);
 128                                         return base;
 129                                 }
 130                                 c->min = p;
 131                                 c->base_reg = i;
 132                         }
 133
 134                         p += map->debugfs_tot_len;
 135                 }
 136         }
 137
 138         /* Close the last entry off if we didn't scan beyond it */
 139         if (c) {
 140                 c->max = p - 1;
 141                 c->max_reg = i - map->reg_stride;
 142                 list_add_tail(&c->list,
 143                               &map->debugfs_off_cache);
 144         }
 145
 146         /*
 147          * This should never happen; we return above if we fail to
 148          * allocate and we should never be in this code if there are
 149          * no registers at all.
 150          */
 151         WARN_ON(list_empty(&map->debugfs_off_cache));
 152         ret = base;
 153
 154         /* Find the relevant block:offset */
 155         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 156                 if (from >= c->min && from <= c->max) {
 157                         fpos_offset = from - c->min;
 158                         reg_offset = fpos_offset / map->debugfs_tot_len;
 159                         *pos = c->min + (reg_offset * map->debugfs_tot_len);
 160                         mutex_unlock(&map->cache_lock);
 161                         return c->base_reg + (reg_offset * map->reg_stride);
 162                 }
 163
 164                 *pos = c->max;
 165                 ret = c->max_reg;
 166         }
 167         mutex_unlock(&map->cache_lock);
 168
 169         return ret;
 170 }
 171
 172 static inline void regmap_calc_tot_len(struct regmap *map,
 173                                        void *buf, size_t count)
 174 {
 175         /* Calculate the length of a fixed format  */
 176         if (!map->debugfs_tot_len) {
 177                 map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
 178                                                            buf, count);
 179                 map->debugfs_val_len = 2 * map->format.val_bytes;
 180                 map->debugfs_tot_len = map->debugfs_reg_len +
 181                         map->debugfs_val_len + 3;      /* : \n */
 182         }
 183 }
 184
 185 static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
 186                                    unsigned int to, char __user *user_buf,
 187                                    size_t count, loff_t *ppos)
 188 {
 189         size_t buf_pos = 0;
 190         loff_t p = *ppos;
 191         ssize_t ret;
 192         int i;
 193         char *buf;
 194         unsigned int val, start_reg;
 195
 196         if (*ppos < 0 || !count)
 197                 return -EINVAL;
 198
 199         buf = kmalloc(count, GFP_KERNEL);
 200         if (!buf)
 201                 return -ENOMEM;
 202
 203         regmap_calc_tot_len(map, buf, count);
 204
 205         /* Work out which register we're starting at */
 206         start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
 207
 208         for (i = start_reg; i <= to; i += map->reg_stride) {
 209                 if (!regmap_readable(map, i))
 210                         continue;
 211
 212                 if (regmap_precious(map, i))
 213                         continue;
 214
 215                 /* If we're in the region the user is trying to read */
 216                 if (p >= *ppos) {
 217                         /* ...but not beyond it */
 218                         if (buf_pos + map->debugfs_tot_len > count)
 219                                 break;
 220
 221                         /* Format the register */
 222                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
 223                                  map->debugfs_reg_len, i - from);
 224                         buf_pos += map->debugfs_reg_len + 2;
 225
 226                         /* Format the value, write all X if we can't read */
 227                         ret = regmap_read(map, i, &val);
 228                         if (ret == 0)
 229                                 snprintf(buf + buf_pos, count - buf_pos,
 230                                          "%.*x", map->debugfs_val_len, val);
 231                         else
 232                                 memset(buf + buf_pos, 'X',
 233                                        map->debugfs_val_len);
 234                         buf_pos += 2 * map->format.val_bytes;
 235
 236                         buf[buf_pos++] = '\n';
 237                 }
 238                 p += map->debugfs_tot_len;
 239         }
 240
 241         ret = buf_pos;
 242
 243         if (copy_to_user(user_buf, buf, buf_pos)) {
 244                 ret = -EFAULT;
 245                 goto out;
 246         }
 247
 248         *ppos += buf_pos;
 249
 250 out:
 251         kfree(buf);
 252         return ret;
 253 }
 254
 255 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 256                                     size_t count, loff_t *ppos)
 257 {
 258         struct regmap *map = file->private_data;
 259
 260         return regmap_read_debugfs(map, 0, map->max_register, user_buf,
 261                                    count, ppos);
 262 }
 263
 264 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 265 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 266 /*
 267  * This can be dangerous especially when we have clients such as
 268  * PMICs, therefore don't provide any real compile time configuration option
 269  * for this feature, people who want to use this will need to modify
 270  * the source code directly.
 271  */
 272 static ssize_t regmap_map_write_file(struct file *file,
 273                                      const char __user *user_buf,
 274                                      size_t count, loff_t *ppos)
 275 {
 276         char buf[32];
 277         size_t buf_size;
 278         char *start = buf;
 279         unsigned long reg, value;
 280         struct regmap *map = file->private_data;
 281         int ret;
 282
 283         buf_size = min(count, (sizeof(buf)-1));
 284         if (copy_from_user(buf, user_buf, buf_size))
 285                 return -EFAULT;
 286         buf[buf_size] = 0;
 287
 288         while (*start == ' ')
 289                 start++;
 290         reg = simple_strtoul(start, &start, 16);
 291         while (*start == ' ')
 292                 start++;
 293         if (kstrtoul(start, 16, &value))
 294                 return -EINVAL;
 295
 296         /* Userspace has been fiddling around behind the kernel's back */
 297         add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 298
 299         ret = regmap_write(map, reg, value);
 300         if (ret < 0)
 301                 return ret;
 302         return buf_size;
 303 }
 304 #else
 305 #define regmap_map_write_file NULL
 306 #endif
 307
 308 static const struct file_operations regmap_map_fops = {
 309         .open = simple_open,
 310         .read = regmap_map_read_file,
 311         .write = regmap_map_write_file,
 312         .llseek = default_llseek,
 313 };
 314
 315 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
 316                                       size_t count, loff_t *ppos)
 317 {
 318         struct regmap_range_node *range = file->private_data;
 319         struct regmap *map = range->map;
 320
 321         return regmap_read_debugfs(map, range->range_min, range->range_max,
 322                                    user_buf, count, ppos);
 323 }
 324
 325 static const struct file_operations regmap_range_fops = {
 326         .open = simple_open,
 327         .read = regmap_range_read_file,
 328         .llseek = default_llseek,
 329 };
 330
 331 static ssize_t regmap_reg_ranges_read_file(struct file *file,
 332                                            char __user *user_buf, size_t count,
 333                                            loff_t *ppos)
 334 {
 335         struct regmap *map = file->private_data;
 336         struct regmap_debugfs_off_cache *c;
 337         loff_t p = 0;
 338         size_t buf_pos = 0;
 339         char *buf;
 340         char *entry;
 341         int ret;
 342
 343         if (*ppos < 0 || !count)
 344                 return -EINVAL;
 345
 346         buf = kmalloc(count, GFP_KERNEL);
 347         if (!buf)
 348                 return -ENOMEM;
 349
 350         entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
 351         if (!entry) {
 352                 kfree(buf);
 353                 return -ENOMEM;
 354         }
 355
 356         /* While we are at it, build the register dump cache
 357          * now so the read() operation on the `registers' file
 358          * can benefit from using the cache.  We do not care
 359          * about the file position information that is contained
 360          * in the cache, just about the actual register blocks */
 361         regmap_calc_tot_len(map, buf, count);
 362         regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
 363
 364         /* Reset file pointer as the fixed-format of the `registers'
 365          * file is not compatible with the `range' file */
 366         p = 0;
 367         mutex_lock(&map->cache_lock);
 368         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 369                 snprintf(entry, PAGE_SIZE, "%x-%x",
 370                          c->base_reg, c->max_reg);
 371                 if (p >= *ppos) {
 372                         if (buf_pos + 1 + strlen(entry) > count)
 373                                 break;
 374                         snprintf(buf + buf_pos, count - buf_pos,
 375                                  "%s", entry);
 376                         buf_pos += strlen(entry);
 377                         buf[buf_pos] = '\n';
 378                         buf_pos++;
 379                 }
 380                 p += strlen(entry) + 1;
 381         }
 382         mutex_unlock(&map->cache_lock);
 383
 384         kfree(entry);
 385         ret = buf_pos;
 386
 387         if (copy_to_user(user_buf, buf, buf_pos)) {
 388                 ret = -EFAULT;
 389                 goto out_buf;
 390         }
 391
 392         *ppos += buf_pos;
 393 out_buf:
 394         kfree(buf);
 395         return ret;
 396 }
 397
 398 static const struct file_operations regmap_reg_ranges_fops = {
 399         .open = simple_open,
 400         .read = regmap_reg_ranges_read_file,
 401         .llseek = default_llseek,
 402 };
 403
 404 static ssize_t regmap_access_read_file(struct file *file,
 405                                        char __user *user_buf, size_t count,
 406                                        loff_t *ppos)
 407 {
 408         int reg_len, tot_len;
 409         size_t buf_pos = 0;
 410         loff_t p = 0;
 411         ssize_t ret;
 412         int i;
 413         struct regmap *map = file->private_data;
 414         char *buf;
 415
 416         if (*ppos < 0 || !count)
 417                 return -EINVAL;
 418
 419         buf = kmalloc(count, GFP_KERNEL);
 420         if (!buf)
 421                 return -ENOMEM;
 422
 423         /* Calculate the length of a fixed format  */
 424         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
 425         tot_len = reg_len + 10; /* ': R W V P\n' */
 426
 427         for (i = 0; i <= map->max_register; i += map->reg_stride) {
 428                 /* Ignore registers which are neither readable nor writable */
 429                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 430                         continue;
 431
 432                 /* If we're in the region the user is trying to read */
 433                 if (p >= *ppos) {
 434                         /* ...but not beyond it */
 435                         if (buf_pos >= count - 1 - tot_len)
 436                                 break;
 437
 438                         /* Format the register */
 439                         snprintf(buf + buf_pos, count - buf_pos,
 440                                  "%.*x: %c %c %c %c\n",
 441                                  reg_len, i,
 442                                  regmap_readable(map, i) ? 'y' : 'n',
 443                                  regmap_writeable(map, i) ? 'y' : 'n',
 444                                  regmap_volatile(map, i) ? 'y' : 'n',
 445                                  regmap_precious(map, i) ? 'y' : 'n');
 446
 447                         buf_pos += tot_len;
 448                 }
 449                 p += tot_len;
 450         }
 451
 452         ret = buf_pos;
 453
 454         if (copy_to_user(user_buf, buf, buf_pos)) {
 455                 ret = -EFAULT;
 456                 goto out;
 457         }
 458
 459         *ppos += buf_pos;
 460
 461 out:
 462         kfree(buf);
 463         return ret;
 464 }
 465
 466 static const struct file_operations regmap_access_fops = {
 467         .open = simple_open,
 468         .read = regmap_access_read_file,
 469         .llseek = default_llseek,
 470 };
 471
 472 void regmap_debugfs_init(struct regmap *map, const char *name)
 473 {
 474         struct rb_node *next;
 475         struct regmap_range_node *range_node;
 476         const char *devname = "dummy";
 477
 478         /* If we don't have the debugfs root yet, postpone init */
 479         if (!regmap_debugfs_root) {
 480                 struct regmap_debugfs_node *node;
 481                 node = kzalloc(sizeof(*node), GFP_KERNEL);
 482                 if (!node)
 483                         return;
 484                 node->map = map;
 485                 node->name = name;
 486                 mutex_lock(&regmap_debugfs_early_lock);
 487                 list_add(&node->link, &regmap_debugfs_early_list);
 488                 mutex_unlock(&regmap_debugfs_early_lock);
 489                 return;
 490         }
 491
 492         INIT_LIST_HEAD(&map->debugfs_off_cache);
 493         mutex_init(&map->cache_lock);
 494
 495         if (map->dev)
 496                 devname = dev_name(map->dev);
 497
 498         if (name) {
 499                 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 500                                               devname, name);
 501                 name = map->debugfs_name;
 502         } else {
 503                 name = devname;
 504         }
 505
 506         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 507         if (!map->debugfs) {
 508                 dev_warn(map->dev, "Failed to create debugfs directory\n");
 509                 return;
 510         }
 511
 512         debugfs_create_file("name", 0400, map->debugfs,
 513                             map, &regmap_name_fops);
 514
 515         debugfs_create_file("range", 0400, map->debugfs,
 516                             map, &regmap_reg_ranges_fops);
 517
 518         if (map->max_register || regmap_readable(map, 0)) {
 519                 umode_t registers_mode;
 520
 521                 if (IS_ENABLED(REGMAP_ALLOW_WRITE_DEBUGFS))
 522                         registers_mode = 0600;
 523                 else
 524                         registers_mode = 0400;
 525
 526                 debugfs_create_file("registers", registers_mode, map->debugfs,
 527                                     map, &regmap_map_fops);
 528                 debugfs_create_file("access", 0400, map->debugfs,
 529                                     map, &regmap_access_fops);
 530         }
 531
 532         if (map->cache_type) {
 533                 debugfs_create_bool("cache_only", 0400, map->debugfs,
 534                                     &map->cache_only);
 535                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 536                                     &map->cache_dirty);
 537                 debugfs_create_bool("cache_bypass", 0400, map->debugfs,
 538                                     &map->cache_bypass);
 539         }
 540
 541         next = rb_first(&map->range_tree);
 542         while (next) {
 543                 range_node = rb_entry(next, struct regmap_range_node, node);
 544
 545                 if (range_node->name)
 546                         debugfs_create_file(range_node->name, 0400,
 547                                             map->debugfs, range_node,
 548                                             &regmap_range_fops);
 549
 550                 next = rb_next(&range_node->node);
 551         }
 552
 553         if (map->cache_ops && map->cache_ops->debugfs_init)
 554                 map->cache_ops->debugfs_init(map);
 555 }
 556
 557 void regmap_debugfs_exit(struct regmap *map)
 558 {
 559         if (map->debugfs) {
 560                 debugfs_remove_recursive(map->debugfs);
 561                 mutex_lock(&map->cache_lock);
 562                 regmap_debugfs_free_dump_cache(map);
 563                 mutex_unlock(&map->cache_lock);
 564                 kfree(map->debugfs_name);
 565         } else {
 566                 struct regmap_debugfs_node *node, *tmp;
 567
 568                 mutex_lock(&regmap_debugfs_early_lock);
 569                 list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list,
 570                                          link) {
 571                         if (node->map == map) {
 572                                 list_del(&node->link);
 573                                 kfree(node);
 574                         }
 575                 }
 576                 mutex_unlock(&regmap_debugfs_early_lock);
 577         }
 578 }
 579
 580 void regmap_debugfs_initcall(void)
 581 {
 582         struct regmap_debugfs_node *node, *tmp;
 583
 584         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 585         if (!regmap_debugfs_root) {
 586                 pr_warn("regmap: Failed to create debugfs root\n");
 587                 return;
 588         }
 589
 590         mutex_lock(&regmap_debugfs_early_lock);
 591         list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list, link) {
 592                 regmap_debugfs_init(node->map, node->name);
 593                 list_del(&node->link);
 594                 kfree(node);
 595         }
 596         mutex_unlock(&regmap_debugfs_early_lock);
 597 }