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
  19 #include "internal.h"
  20
  21 static struct dentry *regmap_debugfs_root;
  22
  23 /* Calculate the length of a fixed format  */
  24 static size_t regmap_calc_reg_len(int max_val, char *buf, size_t buf_size)
  25 {
  26         snprintf(buf, buf_size, "%x", max_val);
  27         return strlen(buf);
  28 }
  29
  30 static ssize_t regmap_name_read_file(struct file *file,
  31                                      char __user *user_buf, size_t count,
  32                                      loff_t *ppos)
  33 {
  34         struct regmap *map = file->private_data;
  35         int ret;
  36         char *buf;
  37
  38         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
  39         if (!buf)
  40                 return -ENOMEM;
  41
  42         ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
  43         if (ret < 0) {
  44                 kfree(buf);
  45                 return ret;
  46         }
  47
  48         ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
  49         kfree(buf);
  50         return ret;
  51 }
  52
  53 static const struct file_operations regmap_name_fops = {
  54         .open = simple_open,
  55         .read = regmap_name_read_file,
  56         .llseek = default_llseek,
  57 };
  58
  59 static void regmap_debugfs_free_dump_cache(struct regmap *map)
  60 {
  61         struct regmap_debugfs_off_cache *c;
  62
  63         while (!list_empty(&map->debugfs_off_cache)) {
  64                 c = list_first_entry(&map->debugfs_off_cache,
  65                                      struct regmap_debugfs_off_cache,
  66                                      list);
  67                 list_del(&c->list);
  68                 kfree(c);
  69         }
  70 }
  71
  72 /*
  73  * Work out where the start offset maps into register numbers, bearing
  74  * in mind that we suppress hidden registers.
  75  */
  76 static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
  77                                                   unsigned int base,
  78                                                   loff_t from,
  79                                                   loff_t *pos)
  80 {
  81         struct regmap_debugfs_off_cache *c = NULL;
  82         loff_t p = 0;
  83         unsigned int i, ret;
  84         unsigned int fpos_offset;
  85         unsigned int reg_offset;
  86
  87         /* Suppress the cache if we're using a subrange */
  88         if (base)
  89                 return base;
  90
  91         /*
  92          * If we don't have a cache build one so we don't have to do a
  93          * linear scan each time.
  94          */
  95         mutex_lock(&map->cache_lock);
  96         i = base;
  97         if (list_empty(&map->debugfs_off_cache)) {
  98                 for (; i <= map->max_register; i += map->reg_stride) {
  99                         /* Skip unprinted registers, closing off cache entry */
 100                         if (!regmap_readable(map, i) ||
 101                             regmap_precious(map, i)) {
 102                                 if (c) {
 103                                         c->max = p - 1;
 104                                         c->max_reg = i - map->reg_stride;
 105                                         list_add_tail(&c->list,
 106                                                       &map->debugfs_off_cache);
 107                                         c = NULL;
 108                                 }
 109
 110                                 continue;
 111                         }
 112
 113                         /* No cache entry?  Start a new one */
 114                         if (!c) {
 115                                 c = kzalloc(sizeof(*c), GFP_KERNEL);
 116                                 if (!c) {
 117                                         regmap_debugfs_free_dump_cache(map);
 118                                         mutex_unlock(&map->cache_lock);
 119                                         return base;
 120                                 }
 121                                 c->min = p;
 122                                 c->base_reg = i;
 123                         }
 124
 125                         p += map->debugfs_tot_len;
 126                 }
 127         }
 128
 129         /* Close the last entry off if we didn't scan beyond it */
 130         if (c) {
 131                 c->max = p - 1;
 132                 c->max_reg = i - map->reg_stride;
 133                 list_add_tail(&c->list,
 134                               &map->debugfs_off_cache);
 135         }
 136
 137         /*
 138          * This should never happen; we return above if we fail to
 139          * allocate and we should never be in this code if there are
 140          * no registers at all.
 141          */
 142         WARN_ON(list_empty(&map->debugfs_off_cache));
 143         ret = base;
 144
 145         /* Find the relevant block:offset */
 146         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 147                 if (from >= c->min && from <= c->max) {
 148                         fpos_offset = from - c->min;
 149                         reg_offset = fpos_offset / map->debugfs_tot_len;
 150                         *pos = c->min + (reg_offset * map->debugfs_tot_len);
 151                         mutex_unlock(&map->cache_lock);
 152                         return c->base_reg + (reg_offset * map->reg_stride);
 153                 }
 154
 155                 *pos = c->max;
 156                 ret = c->max_reg;
 157         }
 158         mutex_unlock(&map->cache_lock);
 159
 160         return ret;
 161 }
 162
 163 static inline void regmap_calc_tot_len(struct regmap *map,
 164                                        void *buf, size_t count)
 165 {
 166         /* Calculate the length of a fixed format  */
 167         if (!map->debugfs_tot_len) {
 168                 map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
 169                                                            buf, count);
 170                 map->debugfs_val_len = 2 * map->format.val_bytes;
 171                 map->debugfs_tot_len = map->debugfs_reg_len +
 172                         map->debugfs_val_len + 3;      /* : \n */
 173         }
 174 }
 175
 176 static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
 177                                    unsigned int to, char __user *user_buf,
 178                                    size_t count, loff_t *ppos)
 179 {
 180         size_t buf_pos = 0;
 181         loff_t p = *ppos;
 182         ssize_t ret;
 183         int i;
 184         char *buf;
 185         unsigned int val, start_reg;
 186
 187         if (*ppos < 0 || !count)
 188                 return -EINVAL;
 189
 190         buf = kmalloc(count, GFP_KERNEL);
 191         if (!buf)
 192                 return -ENOMEM;
 193
 194         regmap_calc_tot_len(map, buf, count);
 195
 196         /* Work out which register we're starting at */
 197         start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
 198
 199         for (i = start_reg; i <= to; i += map->reg_stride) {
 200                 if (!regmap_readable(map, i))
 201                         continue;
 202
 203                 if (regmap_precious(map, i))
 204                         continue;
 205
 206                 /* If we're in the region the user is trying to read */
 207                 if (p >= *ppos) {
 208                         /* ...but not beyond it */
 209                         if (buf_pos + map->debugfs_tot_len > count)
 210                                 break;
 211
 212                         /* Format the register */
 213                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
 214                                  map->debugfs_reg_len, i - from);
 215                         buf_pos += map->debugfs_reg_len + 2;
 216
 217                         /* Format the value, write all X if we can't read */
 218                         ret = regmap_read(map, i, &val);
 219                         if (ret == 0)
 220                                 snprintf(buf + buf_pos, count - buf_pos,
 221                                          "%.*x", map->debugfs_val_len, val);
 222                         else
 223                                 memset(buf + buf_pos, 'X',
 224                                        map->debugfs_val_len);
 225                         buf_pos += 2 * map->format.val_bytes;
 226
 227                         buf[buf_pos++] = '\n';
 228                 }
 229                 p += map->debugfs_tot_len;
 230         }
 231
 232         ret = buf_pos;
 233
 234         if (copy_to_user(user_buf, buf, buf_pos)) {
 235                 ret = -EFAULT;
 236                 goto out;
 237         }
 238
 239         *ppos += buf_pos;
 240
 241 out:
 242         kfree(buf);
 243         return ret;
 244 }
 245
 246 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 247                                     size_t count, loff_t *ppos)
 248 {
 249         struct regmap *map = file->private_data;
 250
 251         return regmap_read_debugfs(map, 0, map->max_register, user_buf,
 252                                    count, ppos);
 253 }
 254
 255 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 256 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 257 /*
 258  * This can be dangerous especially when we have clients such as
 259  * PMICs, therefore don't provide any real compile time configuration option
 260  * for this feature, people who want to use this will need to modify
 261  * the source code directly.
 262  */
 263 static ssize_t regmap_map_write_file(struct file *file,
 264                                      const char __user *user_buf,
 265                                      size_t count, loff_t *ppos)
 266 {
 267         char buf[32];
 268         size_t buf_size;
 269         char *start = buf;
 270         unsigned long reg, value;
 271         struct regmap *map = file->private_data;
 272         int ret;
 273
 274         buf_size = min(count, (sizeof(buf)-1));
 275         if (copy_from_user(buf, user_buf, buf_size))
 276                 return -EFAULT;
 277         buf[buf_size] = 0;
 278
 279         while (*start == ' ')
 280                 start++;
 281         reg = simple_strtoul(start, &start, 16);
 282         while (*start == ' ')
 283                 start++;
 284         if (kstrtoul(start, 16, &value))
 285                 return -EINVAL;
 286
 287         /* Userspace has been fiddling around behind the kernel's back */
 288         add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 289
 290         ret = regmap_write(map, reg, value);
 291         if (ret < 0)
 292                 return ret;
 293         return buf_size;
 294 }
 295 #else
 296 #define regmap_map_write_file NULL
 297 #endif
 298
 299 static const struct file_operations regmap_map_fops = {
 300         .open = simple_open,
 301         .read = regmap_map_read_file,
 302         .write = regmap_map_write_file,
 303         .llseek = default_llseek,
 304 };
 305
 306 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
 307                                       size_t count, loff_t *ppos)
 308 {
 309         struct regmap_range_node *range = file->private_data;
 310         struct regmap *map = range->map;
 311
 312         return regmap_read_debugfs(map, range->range_min, range->range_max,
 313                                    user_buf, count, ppos);
 314 }
 315
 316 static const struct file_operations regmap_range_fops = {
 317         .open = simple_open,
 318         .read = regmap_range_read_file,
 319         .llseek = default_llseek,
 320 };
 321
 322 static ssize_t regmap_reg_ranges_read_file(struct file *file,
 323                                            char __user *user_buf, size_t count,
 324                                            loff_t *ppos)
 325 {
 326         struct regmap *map = file->private_data;
 327         struct regmap_debugfs_off_cache *c;
 328         loff_t p = 0;
 329         size_t buf_pos = 0;
 330         char *buf;
 331         char *entry;
 332         int ret;
 333
 334         if (*ppos < 0 || !count)
 335                 return -EINVAL;
 336
 337         buf = kmalloc(count, GFP_KERNEL);
 338         if (!buf)
 339                 return -ENOMEM;
 340
 341         entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
 342         if (!entry) {
 343                 kfree(buf);
 344                 return -ENOMEM;
 345         }
 346
 347         /* While we are at it, build the register dump cache
 348          * now so the read() operation on the `registers' file
 349          * can benefit from using the cache.  We do not care
 350          * about the file position information that is contained
 351          * in the cache, just about the actual register blocks */
 352         regmap_calc_tot_len(map, buf, count);
 353         regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
 354
 355         /* Reset file pointer as the fixed-format of the `registers'
 356          * file is not compatible with the `range' file */
 357         p = 0;
 358         mutex_lock(&map->cache_lock);
 359         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 360                 snprintf(entry, PAGE_SIZE, "%x-%x",
 361                          c->base_reg, c->max_reg);
 362                 if (p >= *ppos) {
 363                         if (buf_pos + 1 + strlen(entry) > count)
 364                                 break;
 365                         snprintf(buf + buf_pos, count - buf_pos,
 366                                  "%s", entry);
 367                         buf_pos += strlen(entry);
 368                         buf[buf_pos] = '\n';
 369                         buf_pos++;
 370                 }
 371                 p += strlen(entry) + 1;
 372         }
 373         mutex_unlock(&map->cache_lock);
 374
 375         kfree(entry);
 376         ret = buf_pos;
 377
 378         if (copy_to_user(user_buf, buf, buf_pos)) {
 379                 ret = -EFAULT;
 380                 goto out_buf;
 381         }
 382
 383         *ppos += buf_pos;
 384 out_buf:
 385         kfree(buf);
 386         return ret;
 387 }
 388
 389 static const struct file_operations regmap_reg_ranges_fops = {
 390         .open = simple_open,
 391         .read = regmap_reg_ranges_read_file,
 392         .llseek = default_llseek,
 393 };
 394
 395 static ssize_t regmap_access_read_file(struct file *file,
 396                                        char __user *user_buf, size_t count,
 397                                        loff_t *ppos)
 398 {
 399         int reg_len, tot_len;
 400         size_t buf_pos = 0;
 401         loff_t p = 0;
 402         ssize_t ret;
 403         int i;
 404         struct regmap *map = file->private_data;
 405         char *buf;
 406
 407         if (*ppos < 0 || !count)
 408                 return -EINVAL;
 409
 410         buf = kmalloc(count, GFP_KERNEL);
 411         if (!buf)
 412                 return -ENOMEM;
 413
 414         /* Calculate the length of a fixed format  */
 415         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
 416         tot_len = reg_len + 10; /* ': R W V P\n' */
 417
 418         for (i = 0; i <= map->max_register; i += map->reg_stride) {
 419                 /* Ignore registers which are neither readable nor writable */
 420                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 421                         continue;
 422
 423                 /* If we're in the region the user is trying to read */
 424                 if (p >= *ppos) {
 425                         /* ...but not beyond it */
 426                         if (buf_pos >= count - 1 - tot_len)
 427                                 break;
 428
 429                         /* Format the register */
 430                         snprintf(buf + buf_pos, count - buf_pos,
 431                                  "%.*x: %c %c %c %c\n",
 432                                  reg_len, i,
 433                                  regmap_readable(map, i) ? 'y' : 'n',
 434                                  regmap_writeable(map, i) ? 'y' : 'n',
 435                                  regmap_volatile(map, i) ? 'y' : 'n',
 436                                  regmap_precious(map, i) ? 'y' : 'n');
 437
 438                         buf_pos += tot_len;
 439                 }
 440                 p += tot_len;
 441         }
 442
 443         ret = buf_pos;
 444
 445         if (copy_to_user(user_buf, buf, buf_pos)) {
 446                 ret = -EFAULT;
 447                 goto out;
 448         }
 449
 450         *ppos += buf_pos;
 451
 452 out:
 453         kfree(buf);
 454         return ret;
 455 }
 456
 457 static const struct file_operations regmap_access_fops = {
 458         .open = simple_open,
 459         .read = regmap_access_read_file,
 460         .llseek = default_llseek,
 461 };
 462
 463 void regmap_debugfs_init(struct regmap *map, const char *name)
 464 {
 465         struct rb_node *next;
 466         struct regmap_range_node *range_node;
 467
 468         INIT_LIST_HEAD(&map->debugfs_off_cache);
 469         mutex_init(&map->cache_lock);
 470
 471         if (name) {
 472                 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 473                                               dev_name(map->dev), name);
 474                 name = map->debugfs_name;
 475         } else {
 476                 name = dev_name(map->dev);
 477         }
 478
 479         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 480         if (!map->debugfs) {
 481                 dev_warn(map->dev, "Failed to create debugfs directory\n");
 482                 return;
 483         }
 484
 485         debugfs_create_file("name", 0400, map->debugfs,
 486                             map, &regmap_name_fops);
 487
 488         debugfs_create_file("range", 0400, map->debugfs,
 489                             map, &regmap_reg_ranges_fops);
 490
 491         if (map->max_register) {
 492                 debugfs_create_file("registers", 0400, map->debugfs,
 493                                     map, &regmap_map_fops);
 494                 debugfs_create_file("access", 0400, map->debugfs,
 495                                     map, &regmap_access_fops);
 496         }
 497
 498         if (map->cache_type) {
 499                 debugfs_create_bool("cache_only", 0400, map->debugfs,
 500                                     &map->cache_only);
 501                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 502                                     &map->cache_dirty);
 503                 debugfs_create_bool("cache_bypass", 0400, map->debugfs,
 504                                     &map->cache_bypass);
 505         }
 506
 507         next = rb_first(&map->range_tree);
 508         while (next) {
 509                 range_node = rb_entry(next, struct regmap_range_node, node);
 510
 511                 if (range_node->name)
 512                         debugfs_create_file(range_node->name, 0400,
 513                                             map->debugfs, range_node,
 514                                             &regmap_range_fops);
 515
 516                 next = rb_next(&range_node->node);
 517         }
 518 }
 519
 520 void regmap_debugfs_exit(struct regmap *map)
 521 {
 522         debugfs_remove_recursive(map->debugfs);
 523         mutex_lock(&map->cache_lock);
 524         regmap_debugfs_free_dump_cache(map);
 525         mutex_unlock(&map->cache_lock);
 526         kfree(map->debugfs_name);
 527 }
 528
 529 void regmap_debugfs_initcall(void)
 530 {
 531         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 532         if (!regmap_debugfs_root) {
 533                 pr_warn("regmap: Failed to create debugfs root\n");
 534                 return;
 535         }
 536 }