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