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