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 /*
  60  * Work out where the start offset maps into register numbers, bearing
  61  * in mind that we suppress hidden registers.
  62  */
  63 static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
  64                                                   unsigned int base,
  65                                                   loff_t from,
  66                                                   loff_t *pos)
  67 {
  68         struct regmap_debugfs_off_cache *c = NULL;
  69         loff_t p = 0;
  70         unsigned int i, ret;
  71
  72         /*
  73          * If we don't have a cache build one so we don't have to do a
  74          * linear scan each time.
  75          */
  76         if (list_empty(&map->debugfs_off_cache)) {
  77                 for (i = base; i <= map->max_register; i += map->reg_stride) {
  78                         /* Skip unprinted registers, closing off cache entry */
  79                         if (!regmap_readable(map, i) ||
  80                             regmap_precious(map, i)) {
  81                                 if (c) {
  82                                         c->max = p - 1;
  83                                         list_add_tail(&c->list,
  84                                                       &map->debugfs_off_cache);
  85                                         c = NULL;
  86                                 }
  87
  88                                 continue;
  89                         }
  90
  91                         /* No cache entry?  Start a new one */
  92                         if (!c) {
  93                                 c = kzalloc(sizeof(*c), GFP_KERNEL);
  94                                 if (!c)
  95                                         break;
  96                                 c->min = p;
  97                                 c->base_reg = i;
  98                         }
  99
 100                         p += map->debugfs_tot_len;
 101                 }
 102         }
 103
 104         /* Find the relevant block */
 105         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 106                 if (from >= c->min && from <= c->max) {
 107                         *pos = c->min;
 108                         return c->base_reg;
 109                 }
 110
 111                 *pos = c->min;
 112                 ret = c->base_reg;
 113         }
 114
 115         return ret;
 116 }
 117
 118 static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
 119                                    unsigned int to, char __user *user_buf,
 120                                    size_t count, loff_t *ppos)
 121 {
 122         size_t buf_pos = 0;
 123         loff_t p = *ppos;
 124         ssize_t ret;
 125         int i;
 126         char *buf;
 127         unsigned int val, start_reg;
 128
 129         if (*ppos < 0 || !count)
 130                 return -EINVAL;
 131
 132         buf = kmalloc(count, GFP_KERNEL);
 133         if (!buf)
 134                 return -ENOMEM;
 135
 136         /* Calculate the length of a fixed format  */
 137         if (!map->debugfs_tot_len) {
 138                 map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
 139                                                            buf, count);
 140                 map->debugfs_val_len = 2 * map->format.val_bytes;
 141                 map->debugfs_tot_len = map->debugfs_reg_len +
 142                         map->debugfs_val_len + 3;      /* : \n */
 143         }
 144
 145         /* Work out which register we're starting at */
 146         start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
 147
 148         for (i = start_reg; i <= to; i += map->reg_stride) {
 149                 if (!regmap_readable(map, i))
 150                         continue;
 151
 152                 if (regmap_precious(map, i))
 153                         continue;
 154
 155                 /* If we're in the region the user is trying to read */
 156                 if (p >= *ppos) {
 157                         /* ...but not beyond it */
 158                         if (buf_pos + 1 + map->debugfs_tot_len >= count)
 159                                 break;
 160
 161                         /* Format the register */
 162                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
 163                                  map->debugfs_reg_len, i - from);
 164                         buf_pos += map->debugfs_reg_len + 2;
 165
 166                         /* Format the value, write all X if we can't read */
 167                         ret = regmap_read(map, i, &val);
 168                         if (ret == 0)
 169                                 snprintf(buf + buf_pos, count - buf_pos,
 170                                          "%.*x", map->debugfs_val_len, val);
 171                         else
 172                                 memset(buf + buf_pos, 'X',
 173                                        map->debugfs_val_len);
 174                         buf_pos += 2 * map->format.val_bytes;
 175
 176                         buf[buf_pos++] = '\n';
 177                 }
 178                 p += map->debugfs_tot_len;
 179         }
 180
 181         ret = buf_pos;
 182
 183         if (copy_to_user(user_buf, buf, buf_pos)) {
 184                 ret = -EFAULT;
 185                 goto out;
 186         }
 187
 188         *ppos += buf_pos;
 189
 190 out:
 191         kfree(buf);
 192         return ret;
 193 }
 194
 195 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 196                                     size_t count, loff_t *ppos)
 197 {
 198         struct regmap *map = file->private_data;
 199
 200         return regmap_read_debugfs(map, 0, map->max_register, user_buf,
 201                                    count, ppos);
 202 }
 203
 204 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 205 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 206 /*
 207  * This can be dangerous especially when we have clients such as
 208  * PMICs, therefore don't provide any real compile time configuration option
 209  * for this feature, people who want to use this will need to modify
 210  * the source code directly.
 211  */
 212 static ssize_t regmap_map_write_file(struct file *file,
 213                                      const char __user *user_buf,
 214                                      size_t count, loff_t *ppos)
 215 {
 216         char buf[32];
 217         size_t buf_size;
 218         char *start = buf;
 219         unsigned long reg, value;
 220         struct regmap *map = file->private_data;
 221
 222         buf_size = min(count, (sizeof(buf)-1));
 223         if (copy_from_user(buf, user_buf, buf_size))
 224                 return -EFAULT;
 225         buf[buf_size] = 0;
 226
 227         while (*start == ' ')
 228                 start++;
 229         reg = simple_strtoul(start, &start, 16);
 230         while (*start == ' ')
 231                 start++;
 232         if (strict_strtoul(start, 16, &value))
 233                 return -EINVAL;
 234
 235         /* Userspace has been fiddling around behind the kernel's back */
 236         add_taint(TAINT_USER);
 237
 238         regmap_write(map, reg, value);
 239         return buf_size;
 240 }
 241 #else
 242 #define regmap_map_write_file NULL
 243 #endif
 244
 245 static const struct file_operations regmap_map_fops = {
 246         .open = simple_open,
 247         .read = regmap_map_read_file,
 248         .write = regmap_map_write_file,
 249         .llseek = default_llseek,
 250 };
 251
 252 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
 253                                       size_t count, loff_t *ppos)
 254 {
 255         struct regmap_range_node *range = file->private_data;
 256         struct regmap *map = range->map;
 257
 258         return regmap_read_debugfs(map, range->range_min, range->range_max,
 259                                    user_buf, count, ppos);
 260 }
 261
 262 static const struct file_operations regmap_range_fops = {
 263         .open = simple_open,
 264         .read = regmap_range_read_file,
 265         .llseek = default_llseek,
 266 };
 267
 268 static ssize_t regmap_access_read_file(struct file *file,
 269                                        char __user *user_buf, size_t count,
 270                                        loff_t *ppos)
 271 {
 272         int reg_len, tot_len;
 273         size_t buf_pos = 0;
 274         loff_t p = 0;
 275         ssize_t ret;
 276         int i;
 277         struct regmap *map = file->private_data;
 278         char *buf;
 279
 280         if (*ppos < 0 || !count)
 281                 return -EINVAL;
 282
 283         buf = kmalloc(count, GFP_KERNEL);
 284         if (!buf)
 285                 return -ENOMEM;
 286
 287         /* Calculate the length of a fixed format  */
 288         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
 289         tot_len = reg_len + 10; /* ': R W V P\n' */
 290
 291         for (i = 0; i <= map->max_register; i += map->reg_stride) {
 292                 /* Ignore registers which are neither readable nor writable */
 293                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 294                         continue;
 295
 296                 /* If we're in the region the user is trying to read */
 297                 if (p >= *ppos) {
 298                         /* ...but not beyond it */
 299                         if (buf_pos >= count - 1 - tot_len)
 300                                 break;
 301
 302                         /* Format the register */
 303                         snprintf(buf + buf_pos, count - buf_pos,
 304                                  "%.*x: %c %c %c %c\n",
 305                                  reg_len, i,
 306                                  regmap_readable(map, i) ? 'y' : 'n',
 307                                  regmap_writeable(map, i) ? 'y' : 'n',
 308                                  regmap_volatile(map, i) ? 'y' : 'n',
 309                                  regmap_precious(map, i) ? 'y' : 'n');
 310
 311                         buf_pos += tot_len;
 312                 }
 313                 p += tot_len;
 314         }
 315
 316         ret = buf_pos;
 317
 318         if (copy_to_user(user_buf, buf, buf_pos)) {
 319                 ret = -EFAULT;
 320                 goto out;
 321         }
 322
 323         *ppos += buf_pos;
 324
 325 out:
 326         kfree(buf);
 327         return ret;
 328 }
 329
 330 static const struct file_operations regmap_access_fops = {
 331         .open = simple_open,
 332         .read = regmap_access_read_file,
 333         .llseek = default_llseek,
 334 };
 335
 336 void regmap_debugfs_init(struct regmap *map, const char *name)
 337 {
 338         struct rb_node *next;
 339         struct regmap_range_node *range_node;
 340
 341         INIT_LIST_HEAD(&map->debugfs_off_cache);
 342
 343         if (name) {
 344                 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 345                                               dev_name(map->dev), name);
 346                 name = map->debugfs_name;
 347         } else {
 348                 name = dev_name(map->dev);
 349         }
 350
 351         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 352         if (!map->debugfs) {
 353                 dev_warn(map->dev, "Failed to create debugfs directory\n");
 354                 return;
 355         }
 356
 357         debugfs_create_file("name", 0400, map->debugfs,
 358                             map, &regmap_name_fops);
 359
 360         if (map->max_register) {
 361                 debugfs_create_file("registers", 0400, map->debugfs,
 362                                     map, &regmap_map_fops);
 363                 debugfs_create_file("access", 0400, map->debugfs,
 364                                     map, &regmap_access_fops);
 365         }
 366
 367         if (map->cache_type) {
 368                 debugfs_create_bool("cache_only", 0400, map->debugfs,
 369                                     &map->cache_only);
 370                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 371                                     &map->cache_dirty);
 372                 debugfs_create_bool("cache_bypass", 0400, map->debugfs,
 373                                     &map->cache_bypass);
 374         }
 375
 376         next = rb_first(&map->range_tree);
 377         while (next) {
 378                 range_node = rb_entry(next, struct regmap_range_node, node);
 379
 380                 if (range_node->name)
 381                         debugfs_create_file(range_node->name, 0400,
 382                                             map->debugfs, range_node,
 383                                             &regmap_range_fops);
 384
 385                 next = rb_next(&range_node->node);
 386         }
 387 }
 388
 389 void regmap_debugfs_exit(struct regmap *map)
 390 {
 391         struct regmap_debugfs_off_cache *c;
 392
 393         debugfs_remove_recursive(map->debugfs);
 394         while (!list_empty(&map->debugfs_off_cache)) {
 395                 c = list_first_entry(&map->debugfs_off_cache,
 396                                      struct regmap_debugfs_off_cache,
 397                                      list);
 398                 list_del(&c->list);
 399                 kfree(c);
 400         }
 401         kfree(map->debugfs_name);
 402 }
 403
 404 void regmap_debugfs_initcall(void)
 405 {
 406         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 407         if (!regmap_debugfs_root) {
 408                 pr_warn("regmap: Failed to create debugfs root\n");
 409                 return;
 410         }
 411 }