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