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         /* Find the relevant block */
 120         list_for_each_entry(c, &map->debugfs_off_cache, list) {
 121                 if (from >= c->min && from <= c->max) {
 122                         *pos = c->min;
 123                         return c->base_reg;
 124                 }
 125
 126                 *pos = c->min;
 127                 ret = c->base_reg;
 128         }
 129
 130         return ret;
 131 }
 132
 133 static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
 134                                    unsigned int to, char __user *user_buf,
 135                                    size_t count, loff_t *ppos)
 136 {
 137         size_t buf_pos = 0;
 138         loff_t p = *ppos;
 139         ssize_t ret;
 140         int i;
 141         char *buf;
 142         unsigned int val, start_reg;
 143
 144         if (*ppos < 0 || !count)
 145                 return -EINVAL;
 146
 147         buf = kmalloc(count, GFP_KERNEL);
 148         if (!buf)
 149                 return -ENOMEM;
 150
 151         /* Calculate the length of a fixed format  */
 152         if (!map->debugfs_tot_len) {
 153                 map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
 154                                                            buf, count);
 155                 map->debugfs_val_len = 2 * map->format.val_bytes;
 156                 map->debugfs_tot_len = map->debugfs_reg_len +
 157                         map->debugfs_val_len + 3;      /* : \n */
 158         }
 159
 160         /* Work out which register we're starting at */
 161         start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
 162
 163         for (i = start_reg; i <= to; i += map->reg_stride) {
 164                 if (!regmap_readable(map, i))
 165                         continue;
 166
 167                 if (regmap_precious(map, i))
 168                         continue;
 169
 170                 /* If we're in the region the user is trying to read */
 171                 if (p >= *ppos) {
 172                         /* ...but not beyond it */
 173                         if (buf_pos + 1 + map->debugfs_tot_len >= count)
 174                                 break;
 175
 176                         /* Format the register */
 177                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
 178                                  map->debugfs_reg_len, i - from);
 179                         buf_pos += map->debugfs_reg_len + 2;
 180
 181                         /* Format the value, write all X if we can't read */
 182                         ret = regmap_read(map, i, &val);
 183                         if (ret == 0)
 184                                 snprintf(buf + buf_pos, count - buf_pos,
 185                                          "%.*x", map->debugfs_val_len, val);
 186                         else
 187                                 memset(buf + buf_pos, 'X',
 188                                        map->debugfs_val_len);
 189                         buf_pos += 2 * map->format.val_bytes;
 190
 191                         buf[buf_pos++] = '\n';
 192                 }
 193                 p += map->debugfs_tot_len;
 194         }
 195
 196         ret = buf_pos;
 197
 198         if (copy_to_user(user_buf, buf, buf_pos)) {
 199                 ret = -EFAULT;
 200                 goto out;
 201         }
 202
 203         *ppos += buf_pos;
 204
 205 out:
 206         kfree(buf);
 207         return ret;
 208 }
 209
 210 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 211                                     size_t count, loff_t *ppos)
 212 {
 213         struct regmap *map = file->private_data;
 214
 215         return regmap_read_debugfs(map, 0, map->max_register, user_buf,
 216                                    count, ppos);
 217 }
 218
 219 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 220 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 221 /*
 222  * This can be dangerous especially when we have clients such as
 223  * PMICs, therefore don't provide any real compile time configuration option
 224  * for this feature, people who want to use this will need to modify
 225  * the source code directly.
 226  */
 227 static ssize_t regmap_map_write_file(struct file *file,
 228                                      const char __user *user_buf,
 229                                      size_t count, loff_t *ppos)
 230 {
 231         char buf[32];
 232         size_t buf_size;
 233         char *start = buf;
 234         unsigned long reg, value;
 235         struct regmap *map = file->private_data;
 236
 237         buf_size = min(count, (sizeof(buf)-1));
 238         if (copy_from_user(buf, user_buf, buf_size))
 239                 return -EFAULT;
 240         buf[buf_size] = 0;
 241
 242         while (*start == ' ')
 243                 start++;
 244         reg = simple_strtoul(start, &start, 16);
 245         while (*start == ' ')
 246                 start++;
 247         if (strict_strtoul(start, 16, &value))
 248                 return -EINVAL;
 249
 250         /* Userspace has been fiddling around behind the kernel's back */
 251         add_taint(TAINT_USER);
 252
 253         regmap_write(map, reg, value);
 254         return buf_size;
 255 }
 256 #else
 257 #define regmap_map_write_file NULL
 258 #endif
 259
 260 static const struct file_operations regmap_map_fops = {
 261         .open = simple_open,
 262         .read = regmap_map_read_file,
 263         .write = regmap_map_write_file,
 264         .llseek = default_llseek,
 265 };
 266
 267 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
 268                                       size_t count, loff_t *ppos)
 269 {
 270         struct regmap_range_node *range = file->private_data;
 271         struct regmap *map = range->map;
 272
 273         return regmap_read_debugfs(map, range->range_min, range->range_max,
 274                                    user_buf, count, ppos);
 275 }
 276
 277 static const struct file_operations regmap_range_fops = {
 278         .open = simple_open,
 279         .read = regmap_range_read_file,
 280         .llseek = default_llseek,
 281 };
 282
 283 static ssize_t regmap_access_read_file(struct file *file,
 284                                        char __user *user_buf, size_t count,
 285                                        loff_t *ppos)
 286 {
 287         int reg_len, tot_len;
 288         size_t buf_pos = 0;
 289         loff_t p = 0;
 290         ssize_t ret;
 291         int i;
 292         struct regmap *map = file->private_data;
 293         char *buf;
 294
 295         if (*ppos < 0 || !count)
 296                 return -EINVAL;
 297
 298         buf = kmalloc(count, GFP_KERNEL);
 299         if (!buf)
 300                 return -ENOMEM;
 301
 302         /* Calculate the length of a fixed format  */
 303         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
 304         tot_len = reg_len + 10; /* ': R W V P\n' */
 305
 306         for (i = 0; i <= map->max_register; i += map->reg_stride) {
 307                 /* Ignore registers which are neither readable nor writable */
 308                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 309                         continue;
 310
 311                 /* If we're in the region the user is trying to read */
 312                 if (p >= *ppos) {
 313                         /* ...but not beyond it */
 314                         if (buf_pos >= count - 1 - tot_len)
 315                                 break;
 316
 317                         /* Format the register */
 318                         snprintf(buf + buf_pos, count - buf_pos,
 319                                  "%.*x: %c %c %c %c\n",
 320                                  reg_len, i,
 321                                  regmap_readable(map, i) ? 'y' : 'n',
 322                                  regmap_writeable(map, i) ? 'y' : 'n',
 323                                  regmap_volatile(map, i) ? 'y' : 'n',
 324                                  regmap_precious(map, i) ? 'y' : 'n');
 325
 326                         buf_pos += tot_len;
 327                 }
 328                 p += tot_len;
 329         }
 330
 331         ret = buf_pos;
 332
 333         if (copy_to_user(user_buf, buf, buf_pos)) {
 334                 ret = -EFAULT;
 335                 goto out;
 336         }
 337
 338         *ppos += buf_pos;
 339
 340 out:
 341         kfree(buf);
 342         return ret;
 343 }
 344
 345 static const struct file_operations regmap_access_fops = {
 346         .open = simple_open,
 347         .read = regmap_access_read_file,
 348         .llseek = default_llseek,
 349 };
 350
 351 void regmap_debugfs_init(struct regmap *map, const char *name)
 352 {
 353         struct rb_node *next;
 354         struct regmap_range_node *range_node;
 355
 356         INIT_LIST_HEAD(&map->debugfs_off_cache);
 357
 358         if (name) {
 359                 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 360                                               dev_name(map->dev), name);
 361                 name = map->debugfs_name;
 362         } else {
 363                 name = dev_name(map->dev);
 364         }
 365
 366         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 367         if (!map->debugfs) {
 368                 dev_warn(map->dev, "Failed to create debugfs directory\n");
 369                 return;
 370         }
 371
 372         debugfs_create_file("name", 0400, map->debugfs,
 373                             map, &regmap_name_fops);
 374
 375         if (map->max_register) {
 376                 debugfs_create_file("registers", 0400, map->debugfs,
 377                                     map, &regmap_map_fops);
 378                 debugfs_create_file("access", 0400, map->debugfs,
 379                                     map, &regmap_access_fops);
 380         }
 381
 382         if (map->cache_type) {
 383                 debugfs_create_bool("cache_only", 0400, map->debugfs,
 384                                     &map->cache_only);
 385                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 386                                     &map->cache_dirty);
 387                 debugfs_create_bool("cache_bypass", 0400, map->debugfs,
 388                                     &map->cache_bypass);
 389         }
 390
 391         next = rb_first(&map->range_tree);
 392         while (next) {
 393                 range_node = rb_entry(next, struct regmap_range_node, node);
 394
 395                 if (range_node->name)
 396                         debugfs_create_file(range_node->name, 0400,
 397                                             map->debugfs, range_node,
 398                                             &regmap_range_fops);
 399
 400                 next = rb_next(&range_node->node);
 401         }
 402 }
 403
 404 void regmap_debugfs_exit(struct regmap *map)
 405 {
 406         debugfs_remove_recursive(map->debugfs);
 407         regmap_debugfs_free_dump_cache(map);
 408         kfree(map->debugfs_name);
 409 }
 410
 411 void regmap_debugfs_initcall(void)
 412 {
 413         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 414         if (!regmap_debugfs_root) {
 415                 pr_warn("regmap: Failed to create debugfs root\n");
 416                 return;
 417         }
 418 }