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