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