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