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
  85         /*
  86          * If we don't have a cache build one so we don't have to do a
  87          * linear scan each time.
  88          */
  89         if (list_empty(&map->debugfs_off_cache)) {
  90                 for (i = base; i <= map->max_register; i += map->reg_stride) {
  91                         /* Skip unprinted registers, closing off cache entry */
  92                         if (!regmap_readable(map, i) ||
  93                             regmap_precious(map, i)) {
  94                                 if (c) {
  95                                         c->max = p - 1;
  96                                         list_add_tail(&c->list,
  97                                                       &map->debugfs_off_cache);
  98                                         c = NULL;
  99                                 }
 100
 101                                 continue;
 102                         }
 103
 104                         /* No cache entry?  Start a new one */
 105                         if (!c) {
 106                                 c = kzalloc(sizeof(*c), GFP_KERNEL);
 107                                 if (!c) {
 108                                         regmap_debugfs_free_dump_cache(map);
 109                                         return base;
 110                                 }
 111                                 c->min = p;
 112                                 c->base_reg = i;
 113                         }
 114
 115                         p += map->debugfs_tot_len;
 116                 }
 117         }
 118
 119         /* Close the last entry off if we didn't scan beyond it */
 120         if (c) {
 121                 c->max = p - 1;
 122                 list_add_tail(&c->list,
 123                               &map->debugfs_off_cache);
 124         }
 125
 126         /*
 127          * This should never happen; we return above if we fail to
 128          * allocate and we should never be in this code if there are
 129          * no registers at all.
 130          */
 131         WARN_ON(list_empty(&map->debugfs_off_cache));
 132         ret = base;
 133
 134         /* Find the relevant block */
 135         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 136                 if (from >= c->min && from <= c->max) {
 137                         *pos = c->min;
 138                         return c->base_reg;
 139                 }
 140
 141                 *pos = c->min;
 142                 ret = c->base_reg;
 143         }
 144
 145         return ret;
 146 }
 147
 148 static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
 149                                    unsigned int to, char __user *user_buf,
 150                                    size_t count, loff_t *ppos)
 151 {
 152         size_t buf_pos = 0;
 153         loff_t p = *ppos;
 154         ssize_t ret;
 155         int i;
 156         char *buf;
 157         unsigned int val, start_reg;
 158
 159         if (*ppos < 0 || !count)
 160                 return -EINVAL;
 161
 162         buf = kmalloc(count, GFP_KERNEL);
 163         if (!buf)
 164                 return -ENOMEM;
 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         /* Work out which register we're starting at */
 176         start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
 177
 178         for (i = start_reg; i <= to; i += map->reg_stride) {
 179                 if (!regmap_readable(map, i))
 180                         continue;
 181
 182                 if (regmap_precious(map, i))
 183                         continue;
 184
 185                 /* If we're in the region the user is trying to read */
 186                 if (p >= *ppos) {
 187                         /* ...but not beyond it */
 188                         if (buf_pos + 1 + map->debugfs_tot_len >= count)
 189                                 break;
 190
 191                         /* Format the register */
 192                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
 193                                  map->debugfs_reg_len, i - from);
 194                         buf_pos += map->debugfs_reg_len + 2;
 195
 196                         /* Format the value, write all X if we can't read */
 197                         ret = regmap_read(map, i, &val);
 198                         if (ret == 0)
 199                                 snprintf(buf + buf_pos, count - buf_pos,
 200                                          "%.*x", map->debugfs_val_len, val);
 201                         else
 202                                 memset(buf + buf_pos, 'X',
 203                                        map->debugfs_val_len);
 204                         buf_pos += 2 * map->format.val_bytes;
 205
 206                         buf[buf_pos++] = '\n';
 207                 }
 208                 p += map->debugfs_tot_len;
 209         }
 210
 211         ret = buf_pos;
 212
 213         if (copy_to_user(user_buf, buf, buf_pos)) {
 214                 ret = -EFAULT;
 215                 goto out;
 216         }
 217
 218         *ppos += buf_pos;
 219
 220 out:
 221         kfree(buf);
 222         return ret;
 223 }
 224
 225 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 226                                     size_t count, loff_t *ppos)
 227 {
 228         struct regmap *map = file->private_data;
 229
 230         return regmap_read_debugfs(map, 0, map->max_register, user_buf,
 231                                    count, ppos);
 232 }
 233
 234 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 235 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 236 /*
 237  * This can be dangerous especially when we have clients such as
 238  * PMICs, therefore don't provide any real compile time configuration option
 239  * for this feature, people who want to use this will need to modify
 240  * the source code directly.
 241  */
 242 static ssize_t regmap_map_write_file(struct file *file,
 243                                      const char __user *user_buf,
 244                                      size_t count, loff_t *ppos)
 245 {
 246         char buf[32];
 247         size_t buf_size;
 248         char *start = buf;
 249         unsigned long reg, value;
 250         struct regmap *map = file->private_data;
 251
 252         buf_size = min(count, (sizeof(buf)-1));
 253         if (copy_from_user(buf, user_buf, buf_size))
 254                 return -EFAULT;
 255         buf[buf_size] = 0;
 256
 257         while (*start == ' ')
 258                 start++;
 259         reg = simple_strtoul(start, &start, 16);
 260         while (*start == ' ')
 261                 start++;
 262         if (strict_strtoul(start, 16, &value))
 263                 return -EINVAL;
 264
 265         /* Userspace has been fiddling around behind the kernel's back */
 266         add_taint(TAINT_USER);
 267
 268         regmap_write(map, reg, value);
 269         return buf_size;
 270 }
 271 #else
 272 #define regmap_map_write_file NULL
 273 #endif
 274
 275 static const struct file_operations regmap_map_fops = {
 276         .open = simple_open,
 277         .read = regmap_map_read_file,
 278         .write = regmap_map_write_file,
 279         .llseek = default_llseek,
 280 };
 281
 282 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
 283                                       size_t count, loff_t *ppos)
 284 {
 285         struct regmap_range_node *range = file->private_data;
 286         struct regmap *map = range->map;
 287
 288         return regmap_read_debugfs(map, range->range_min, range->range_max,
 289                                    user_buf, count, ppos);
 290 }
 291
 292 static const struct file_operations regmap_range_fops = {
 293         .open = simple_open,
 294         .read = regmap_range_read_file,
 295         .llseek = default_llseek,
 296 };
 297
 298 static ssize_t regmap_access_read_file(struct file *file,
 299                                        char __user *user_buf, size_t count,
 300                                        loff_t *ppos)
 301 {
 302         int reg_len, tot_len;
 303         size_t buf_pos = 0;
 304         loff_t p = 0;
 305         ssize_t ret;
 306         int i;
 307         struct regmap *map = file->private_data;
 308         char *buf;
 309
 310         if (*ppos < 0 || !count)
 311                 return -EINVAL;
 312
 313         buf = kmalloc(count, GFP_KERNEL);
 314         if (!buf)
 315                 return -ENOMEM;
 316
 317         /* Calculate the length of a fixed format  */
 318         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
 319         tot_len = reg_len + 10; /* ': R W V P\n' */
 320
 321         for (i = 0; i <= map->max_register; i += map->reg_stride) {
 322                 /* Ignore registers which are neither readable nor writable */
 323                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 324                         continue;
 325
 326                 /* If we're in the region the user is trying to read */
 327                 if (p >= *ppos) {
 328                         /* ...but not beyond it */
 329                         if (buf_pos >= count - 1 - tot_len)
 330                                 break;
 331
 332                         /* Format the register */
 333                         snprintf(buf + buf_pos, count - buf_pos,
 334                                  "%.*x: %c %c %c %c\n",
 335                                  reg_len, i,
 336                                  regmap_readable(map, i) ? 'y' : 'n',
 337                                  regmap_writeable(map, i) ? 'y' : 'n',
 338                                  regmap_volatile(map, i) ? 'y' : 'n',
 339                                  regmap_precious(map, i) ? 'y' : 'n');
 340
 341                         buf_pos += tot_len;
 342                 }
 343                 p += tot_len;
 344         }
 345
 346         ret = buf_pos;
 347
 348         if (copy_to_user(user_buf, buf, buf_pos)) {
 349                 ret = -EFAULT;
 350                 goto out;
 351         }
 352
 353         *ppos += buf_pos;
 354
 355 out:
 356         kfree(buf);
 357         return ret;
 358 }
 359
 360 static const struct file_operations regmap_access_fops = {
 361         .open = simple_open,
 362         .read = regmap_access_read_file,
 363         .llseek = default_llseek,
 364 };
 365
 366 void regmap_debugfs_init(struct regmap *map, const char *name)
 367 {
 368         struct rb_node *next;
 369         struct regmap_range_node *range_node;
 370
 371         INIT_LIST_HEAD(&map->debugfs_off_cache);
 372
 373         if (name) {
 374                 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 375                                               dev_name(map->dev), name);
 376                 name = map->debugfs_name;
 377         } else {
 378                 name = dev_name(map->dev);
 379         }
 380
 381         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 382         if (!map->debugfs) {
 383                 dev_warn(map->dev, "Failed to create debugfs directory\n");
 384                 return;
 385         }
 386
 387         debugfs_create_file("name", 0400, map->debugfs,
 388                             map, &regmap_name_fops);
 389
 390         if (map->max_register) {
 391                 debugfs_create_file("registers", 0400, map->debugfs,
 392                                     map, &regmap_map_fops);
 393                 debugfs_create_file("access", 0400, map->debugfs,
 394                                     map, &regmap_access_fops);
 395         }
 396
 397         if (map->cache_type) {
 398                 debugfs_create_bool("cache_only", 0400, map->debugfs,
 399                                     &map->cache_only);
 400                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 401                                     &map->cache_dirty);
 402                 debugfs_create_bool("cache_bypass", 0400, map->debugfs,
 403                                     &map->cache_bypass);
 404         }
 405
 406         next = rb_first(&map->range_tree);
 407         while (next) {
 408                 range_node = rb_entry(next, struct regmap_range_node, node);
 409
 410                 if (range_node->name)
 411                         debugfs_create_file(range_node->name, 0400,
 412                                             map->debugfs, range_node,
 413                                             &regmap_range_fops);
 414
 415                 next = rb_next(&range_node->node);
 416         }
 417 }
 418
 419 void regmap_debugfs_exit(struct regmap *map)
 420 {
 421         debugfs_remove_recursive(map->debugfs);
 422         regmap_debugfs_free_dump_cache(map);
 423         kfree(map->debugfs_name);
 424 }
 425
 426 void regmap_debugfs_initcall(void)
 427 {
 428         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 429         if (!regmap_debugfs_root) {
 430                 pr_warn("regmap: Failed to create debugfs root\n");
 431                 return;
 432         }
 433 }