linux/fs/debugfs/file.c
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   1/*
   2 *  file.c - part of debugfs, a tiny little debug file system
   3 *
   4 *  Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
   5 *  Copyright (C) 2004 IBM Inc.
   6 *
   7 *      This program is free software; you can redistribute it and/or
   8 *      modify it under the terms of the GNU General Public License version
   9 *      2 as published by the Free Software Foundation.
  10 *
  11 *  debugfs is for people to use instead of /proc or /sys.
  12 *  See Documentation/DocBook/filesystems for more details.
  13 *
  14 */
  15
  16#include <linux/module.h>
  17#include <linux/fs.h>
  18#include <linux/seq_file.h>
  19#include <linux/pagemap.h>
  20#include <linux/namei.h>
  21#include <linux/debugfs.h>
  22#include <linux/io.h>
  23#include <linux/slab.h>
  24
  25static ssize_t default_read_file(struct file *file, char __user *buf,
  26                                 size_t count, loff_t *ppos)
  27{
  28        return 0;
  29}
  30
  31static ssize_t default_write_file(struct file *file, const char __user *buf,
  32                                   size_t count, loff_t *ppos)
  33{
  34        return count;
  35}
  36
  37const struct file_operations debugfs_file_operations = {
  38        .read =         default_read_file,
  39        .write =        default_write_file,
  40        .open =         simple_open,
  41        .llseek =       noop_llseek,
  42};
  43
  44static void *debugfs_follow_link(struct dentry *dentry, struct nameidata *nd)
  45{
  46        nd_set_link(nd, dentry->d_inode->i_private);
  47        return NULL;
  48}
  49
  50const struct inode_operations debugfs_link_operations = {
  51        .readlink       = generic_readlink,
  52        .follow_link    = debugfs_follow_link,
  53};
  54
  55static int debugfs_u8_set(void *data, u64 val)
  56{
  57        *(u8 *)data = val;
  58        return 0;
  59}
  60static int debugfs_u8_get(void *data, u64 *val)
  61{
  62        *val = *(u8 *)data;
  63        return 0;
  64}
  65DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
  66DEFINE_SIMPLE_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
  67DEFINE_SIMPLE_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
  68
  69/**
  70 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
  71 * @name: a pointer to a string containing the name of the file to create.
  72 * @mode: the permission that the file should have
  73 * @parent: a pointer to the parent dentry for this file.  This should be a
  74 *          directory dentry if set.  If this parameter is %NULL, then the
  75 *          file will be created in the root of the debugfs filesystem.
  76 * @value: a pointer to the variable that the file should read to and write
  77 *         from.
  78 *
  79 * This function creates a file in debugfs with the given name that
  80 * contains the value of the variable @value.  If the @mode variable is so
  81 * set, it can be read from, and written to.
  82 *
  83 * This function will return a pointer to a dentry if it succeeds.  This
  84 * pointer must be passed to the debugfs_remove() function when the file is
  85 * to be removed (no automatic cleanup happens if your module is unloaded,
  86 * you are responsible here.)  If an error occurs, %NULL will be returned.
  87 *
  88 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
  89 * returned.  It is not wise to check for this value, but rather, check for
  90 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
  91 * code.
  92 */
  93struct dentry *debugfs_create_u8(const char *name, umode_t mode,
  94                                 struct dentry *parent, u8 *value)
  95{
  96        /* if there are no write bits set, make read only */
  97        if (!(mode & S_IWUGO))
  98                return debugfs_create_file(name, mode, parent, value, &fops_u8_ro);
  99        /* if there are no read bits set, make write only */
 100        if (!(mode & S_IRUGO))
 101                return debugfs_create_file(name, mode, parent, value, &fops_u8_wo);
 102
 103        return debugfs_create_file(name, mode, parent, value, &fops_u8);
 104}
 105EXPORT_SYMBOL_GPL(debugfs_create_u8);
 106
 107static int debugfs_u16_set(void *data, u64 val)
 108{
 109        *(u16 *)data = val;
 110        return 0;
 111}
 112static int debugfs_u16_get(void *data, u64 *val)
 113{
 114        *val = *(u16 *)data;
 115        return 0;
 116}
 117DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
 118DEFINE_SIMPLE_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
 119DEFINE_SIMPLE_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
 120
 121/**
 122 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
 123 * @name: a pointer to a string containing the name of the file to create.
 124 * @mode: the permission that the file should have
 125 * @parent: a pointer to the parent dentry for this file.  This should be a
 126 *          directory dentry if set.  If this parameter is %NULL, then the
 127 *          file will be created in the root of the debugfs filesystem.
 128 * @value: a pointer to the variable that the file should read to and write
 129 *         from.
 130 *
 131 * This function creates a file in debugfs with the given name that
 132 * contains the value of the variable @value.  If the @mode variable is so
 133 * set, it can be read from, and written to.
 134 *
 135 * This function will return a pointer to a dentry if it succeeds.  This
 136 * pointer must be passed to the debugfs_remove() function when the file is
 137 * to be removed (no automatic cleanup happens if your module is unloaded,
 138 * you are responsible here.)  If an error occurs, %NULL will be returned.
 139 *
 140 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 141 * returned.  It is not wise to check for this value, but rather, check for
 142 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 143 * code.
 144 */
 145struct dentry *debugfs_create_u16(const char *name, umode_t mode,
 146                                  struct dentry *parent, u16 *value)
 147{
 148        /* if there are no write bits set, make read only */
 149        if (!(mode & S_IWUGO))
 150                return debugfs_create_file(name, mode, parent, value, &fops_u16_ro);
 151        /* if there are no read bits set, make write only */
 152        if (!(mode & S_IRUGO))
 153                return debugfs_create_file(name, mode, parent, value, &fops_u16_wo);
 154
 155        return debugfs_create_file(name, mode, parent, value, &fops_u16);
 156}
 157EXPORT_SYMBOL_GPL(debugfs_create_u16);
 158
 159static int debugfs_u32_set(void *data, u64 val)
 160{
 161        *(u32 *)data = val;
 162        return 0;
 163}
 164static int debugfs_u32_get(void *data, u64 *val)
 165{
 166        *val = *(u32 *)data;
 167        return 0;
 168}
 169DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
 170DEFINE_SIMPLE_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
 171DEFINE_SIMPLE_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
 172
 173/**
 174 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
 175 * @name: a pointer to a string containing the name of the file to create.
 176 * @mode: the permission that the file should have
 177 * @parent: a pointer to the parent dentry for this file.  This should be a
 178 *          directory dentry if set.  If this parameter is %NULL, then the
 179 *          file will be created in the root of the debugfs filesystem.
 180 * @value: a pointer to the variable that the file should read to and write
 181 *         from.
 182 *
 183 * This function creates a file in debugfs with the given name that
 184 * contains the value of the variable @value.  If the @mode variable is so
 185 * set, it can be read from, and written to.
 186 *
 187 * This function will return a pointer to a dentry if it succeeds.  This
 188 * pointer must be passed to the debugfs_remove() function when the file is
 189 * to be removed (no automatic cleanup happens if your module is unloaded,
 190 * you are responsible here.)  If an error occurs, %NULL will be returned.
 191 *
 192 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 193 * returned.  It is not wise to check for this value, but rather, check for
 194 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 195 * code.
 196 */
 197struct dentry *debugfs_create_u32(const char *name, umode_t mode,
 198                                 struct dentry *parent, u32 *value)
 199{
 200        /* if there are no write bits set, make read only */
 201        if (!(mode & S_IWUGO))
 202                return debugfs_create_file(name, mode, parent, value, &fops_u32_ro);
 203        /* if there are no read bits set, make write only */
 204        if (!(mode & S_IRUGO))
 205                return debugfs_create_file(name, mode, parent, value, &fops_u32_wo);
 206
 207        return debugfs_create_file(name, mode, parent, value, &fops_u32);
 208}
 209EXPORT_SYMBOL_GPL(debugfs_create_u32);
 210
 211static int debugfs_u64_set(void *data, u64 val)
 212{
 213        *(u64 *)data = val;
 214        return 0;
 215}
 216
 217static int debugfs_u64_get(void *data, u64 *val)
 218{
 219        *val = *(u64 *)data;
 220        return 0;
 221}
 222DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
 223DEFINE_SIMPLE_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
 224DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
 225
 226/**
 227 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
 228 * @name: a pointer to a string containing the name of the file to create.
 229 * @mode: the permission that the file should have
 230 * @parent: a pointer to the parent dentry for this file.  This should be a
 231 *          directory dentry if set.  If this parameter is %NULL, then the
 232 *          file will be created in the root of the debugfs filesystem.
 233 * @value: a pointer to the variable that the file should read to and write
 234 *         from.
 235 *
 236 * This function creates a file in debugfs with the given name that
 237 * contains the value of the variable @value.  If the @mode variable is so
 238 * set, it can be read from, and written to.
 239 *
 240 * This function will return a pointer to a dentry if it succeeds.  This
 241 * pointer must be passed to the debugfs_remove() function when the file is
 242 * to be removed (no automatic cleanup happens if your module is unloaded,
 243 * you are responsible here.)  If an error occurs, %NULL will be returned.
 244 *
 245 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 246 * returned.  It is not wise to check for this value, but rather, check for
 247 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 248 * code.
 249 */
 250struct dentry *debugfs_create_u64(const char *name, umode_t mode,
 251                                 struct dentry *parent, u64 *value)
 252{
 253        /* if there are no write bits set, make read only */
 254        if (!(mode & S_IWUGO))
 255                return debugfs_create_file(name, mode, parent, value, &fops_u64_ro);
 256        /* if there are no read bits set, make write only */
 257        if (!(mode & S_IRUGO))
 258                return debugfs_create_file(name, mode, parent, value, &fops_u64_wo);
 259
 260        return debugfs_create_file(name, mode, parent, value, &fops_u64);
 261}
 262EXPORT_SYMBOL_GPL(debugfs_create_u64);
 263
 264DEFINE_SIMPLE_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
 265DEFINE_SIMPLE_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
 266DEFINE_SIMPLE_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
 267
 268DEFINE_SIMPLE_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set, "0x%04llx\n");
 269DEFINE_SIMPLE_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
 270DEFINE_SIMPLE_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
 271
 272DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%08llx\n");
 273DEFINE_SIMPLE_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
 274DEFINE_SIMPLE_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
 275
 276DEFINE_SIMPLE_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set, "0x%016llx\n");
 277
 278/*
 279 * debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value
 280 *
 281 * These functions are exactly the same as the above functions (but use a hex
 282 * output for the decimal challenged). For details look at the above unsigned
 283 * decimal functions.
 284 */
 285
 286/**
 287 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
 288 * @name: a pointer to a string containing the name of the file to create.
 289 * @mode: the permission that the file should have
 290 * @parent: a pointer to the parent dentry for this file.  This should be a
 291 *          directory dentry if set.  If this parameter is %NULL, then the
 292 *          file will be created in the root of the debugfs filesystem.
 293 * @value: a pointer to the variable that the file should read to and write
 294 *         from.
 295 */
 296struct dentry *debugfs_create_x8(const char *name, umode_t mode,
 297                                 struct dentry *parent, u8 *value)
 298{
 299        /* if there are no write bits set, make read only */
 300        if (!(mode & S_IWUGO))
 301                return debugfs_create_file(name, mode, parent, value, &fops_x8_ro);
 302        /* if there are no read bits set, make write only */
 303        if (!(mode & S_IRUGO))
 304                return debugfs_create_file(name, mode, parent, value, &fops_x8_wo);
 305
 306        return debugfs_create_file(name, mode, parent, value, &fops_x8);
 307}
 308EXPORT_SYMBOL_GPL(debugfs_create_x8);
 309
 310/**
 311 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
 312 * @name: a pointer to a string containing the name of the file to create.
 313 * @mode: the permission that the file should have
 314 * @parent: a pointer to the parent dentry for this file.  This should be a
 315 *          directory dentry if set.  If this parameter is %NULL, then the
 316 *          file will be created in the root of the debugfs filesystem.
 317 * @value: a pointer to the variable that the file should read to and write
 318 *         from.
 319 */
 320struct dentry *debugfs_create_x16(const char *name, umode_t mode,
 321                                 struct dentry *parent, u16 *value)
 322{
 323        /* if there are no write bits set, make read only */
 324        if (!(mode & S_IWUGO))
 325                return debugfs_create_file(name, mode, parent, value, &fops_x16_ro);
 326        /* if there are no read bits set, make write only */
 327        if (!(mode & S_IRUGO))
 328                return debugfs_create_file(name, mode, parent, value, &fops_x16_wo);
 329
 330        return debugfs_create_file(name, mode, parent, value, &fops_x16);
 331}
 332EXPORT_SYMBOL_GPL(debugfs_create_x16);
 333
 334/**
 335 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
 336 * @name: a pointer to a string containing the name of the file to create.
 337 * @mode: the permission that the file should have
 338 * @parent: a pointer to the parent dentry for this file.  This should be a
 339 *          directory dentry if set.  If this parameter is %NULL, then the
 340 *          file will be created in the root of the debugfs filesystem.
 341 * @value: a pointer to the variable that the file should read to and write
 342 *         from.
 343 */
 344struct dentry *debugfs_create_x32(const char *name, umode_t mode,
 345                                 struct dentry *parent, u32 *value)
 346{
 347        /* if there are no write bits set, make read only */
 348        if (!(mode & S_IWUGO))
 349                return debugfs_create_file(name, mode, parent, value, &fops_x32_ro);
 350        /* if there are no read bits set, make write only */
 351        if (!(mode & S_IRUGO))
 352                return debugfs_create_file(name, mode, parent, value, &fops_x32_wo);
 353
 354        return debugfs_create_file(name, mode, parent, value, &fops_x32);
 355}
 356EXPORT_SYMBOL_GPL(debugfs_create_x32);
 357
 358/**
 359 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
 360 * @name: a pointer to a string containing the name of the file to create.
 361 * @mode: the permission that the file should have
 362 * @parent: a pointer to the parent dentry for this file.  This should be a
 363 *          directory dentry if set.  If this parameter is %NULL, then the
 364 *          file will be created in the root of the debugfs filesystem.
 365 * @value: a pointer to the variable that the file should read to and write
 366 *         from.
 367 */
 368struct dentry *debugfs_create_x64(const char *name, umode_t mode,
 369                                 struct dentry *parent, u64 *value)
 370{
 371        return debugfs_create_file(name, mode, parent, value, &fops_x64);
 372}
 373EXPORT_SYMBOL_GPL(debugfs_create_x64);
 374
 375
 376static int debugfs_size_t_set(void *data, u64 val)
 377{
 378        *(size_t *)data = val;
 379        return 0;
 380}
 381static int debugfs_size_t_get(void *data, u64 *val)
 382{
 383        *val = *(size_t *)data;
 384        return 0;
 385}
 386DEFINE_SIMPLE_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
 387                        "%llu\n");      /* %llu and %zu are more or less the same */
 388
 389/**
 390 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
 391 * @name: a pointer to a string containing the name of the file to create.
 392 * @mode: the permission that the file should have
 393 * @parent: a pointer to the parent dentry for this file.  This should be a
 394 *          directory dentry if set.  If this parameter is %NULL, then the
 395 *          file will be created in the root of the debugfs filesystem.
 396 * @value: a pointer to the variable that the file should read to and write
 397 *         from.
 398 */
 399struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
 400                                     struct dentry *parent, size_t *value)
 401{
 402        return debugfs_create_file(name, mode, parent, value, &fops_size_t);
 403}
 404EXPORT_SYMBOL_GPL(debugfs_create_size_t);
 405
 406
 407static ssize_t read_file_bool(struct file *file, char __user *user_buf,
 408                              size_t count, loff_t *ppos)
 409{
 410        char buf[3];
 411        u32 *val = file->private_data;
 412        
 413        if (*val)
 414                buf[0] = 'Y';
 415        else
 416                buf[0] = 'N';
 417        buf[1] = '\n';
 418        buf[2] = 0x00;
 419        return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
 420}
 421
 422static ssize_t write_file_bool(struct file *file, const char __user *user_buf,
 423                               size_t count, loff_t *ppos)
 424{
 425        char buf[32];
 426        size_t buf_size;
 427        bool bv;
 428        u32 *val = file->private_data;
 429
 430        buf_size = min(count, (sizeof(buf)-1));
 431        if (copy_from_user(buf, user_buf, buf_size))
 432                return -EFAULT;
 433
 434        if (strtobool(buf, &bv) == 0)
 435                *val = bv;
 436
 437        return count;
 438}
 439
 440static const struct file_operations fops_bool = {
 441        .read =         read_file_bool,
 442        .write =        write_file_bool,
 443        .open =         simple_open,
 444        .llseek =       default_llseek,
 445};
 446
 447/**
 448 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
 449 * @name: a pointer to a string containing the name of the file to create.
 450 * @mode: the permission that the file should have
 451 * @parent: a pointer to the parent dentry for this file.  This should be a
 452 *          directory dentry if set.  If this parameter is %NULL, then the
 453 *          file will be created in the root of the debugfs filesystem.
 454 * @value: a pointer to the variable that the file should read to and write
 455 *         from.
 456 *
 457 * This function creates a file in debugfs with the given name that
 458 * contains the value of the variable @value.  If the @mode variable is so
 459 * set, it can be read from, and written to.
 460 *
 461 * This function will return a pointer to a dentry if it succeeds.  This
 462 * pointer must be passed to the debugfs_remove() function when the file is
 463 * to be removed (no automatic cleanup happens if your module is unloaded,
 464 * you are responsible here.)  If an error occurs, %NULL will be returned.
 465 *
 466 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 467 * returned.  It is not wise to check for this value, but rather, check for
 468 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 469 * code.
 470 */
 471struct dentry *debugfs_create_bool(const char *name, umode_t mode,
 472                                   struct dentry *parent, u32 *value)
 473{
 474        return debugfs_create_file(name, mode, parent, value, &fops_bool);
 475}
 476EXPORT_SYMBOL_GPL(debugfs_create_bool);
 477
 478static ssize_t read_file_blob(struct file *file, char __user *user_buf,
 479                              size_t count, loff_t *ppos)
 480{
 481        struct debugfs_blob_wrapper *blob = file->private_data;
 482        return simple_read_from_buffer(user_buf, count, ppos, blob->data,
 483                        blob->size);
 484}
 485
 486static const struct file_operations fops_blob = {
 487        .read =         read_file_blob,
 488        .open =         simple_open,
 489        .llseek =       default_llseek,
 490};
 491
 492/**
 493 * debugfs_create_blob - create a debugfs file that is used to read a binary blob
 494 * @name: a pointer to a string containing the name of the file to create.
 495 * @mode: the permission that the file should have
 496 * @parent: a pointer to the parent dentry for this file.  This should be a
 497 *          directory dentry if set.  If this parameter is %NULL, then the
 498 *          file will be created in the root of the debugfs filesystem.
 499 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
 500 *        to the blob data and the size of the data.
 501 *
 502 * This function creates a file in debugfs with the given name that exports
 503 * @blob->data as a binary blob. If the @mode variable is so set it can be
 504 * read from. Writing is not supported.
 505 *
 506 * This function will return a pointer to a dentry if it succeeds.  This
 507 * pointer must be passed to the debugfs_remove() function when the file is
 508 * to be removed (no automatic cleanup happens if your module is unloaded,
 509 * you are responsible here.)  If an error occurs, %NULL will be returned.
 510 *
 511 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 512 * returned.  It is not wise to check for this value, but rather, check for
 513 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 514 * code.
 515 */
 516struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 517                                   struct dentry *parent,
 518                                   struct debugfs_blob_wrapper *blob)
 519{
 520        return debugfs_create_file(name, mode, parent, blob, &fops_blob);
 521}
 522EXPORT_SYMBOL_GPL(debugfs_create_blob);
 523
 524struct array_data {
 525        void *array;
 526        u32 elements;
 527};
 528
 529static size_t u32_format_array(char *buf, size_t bufsize,
 530                               u32 *array, int array_size)
 531{
 532        size_t ret = 0;
 533
 534        while (--array_size >= 0) {
 535                size_t len;
 536                char term = array_size ? ' ' : '\n';
 537
 538                len = snprintf(buf, bufsize, "%u%c", *array++, term);
 539                ret += len;
 540
 541                buf += len;
 542                bufsize -= len;
 543        }
 544        return ret;
 545}
 546
 547static int u32_array_open(struct inode *inode, struct file *file)
 548{
 549        struct array_data *data = inode->i_private;
 550        int size, elements = data->elements;
 551        char *buf;
 552
 553        /*
 554         * Max size:
 555         *  - 10 digits + ' '/'\n' = 11 bytes per number
 556         *  - terminating NUL character
 557         */
 558        size = elements*11;
 559        buf = kmalloc(size+1, GFP_KERNEL);
 560        if (!buf)
 561                return -ENOMEM;
 562        buf[size] = 0;
 563
 564        file->private_data = buf;
 565        u32_format_array(buf, size, data->array, data->elements);
 566
 567        return nonseekable_open(inode, file);
 568}
 569
 570static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
 571                              loff_t *ppos)
 572{
 573        size_t size = strlen(file->private_data);
 574
 575        return simple_read_from_buffer(buf, len, ppos,
 576                                        file->private_data, size);
 577}
 578
 579static int u32_array_release(struct inode *inode, struct file *file)
 580{
 581        kfree(file->private_data);
 582
 583        return 0;
 584}
 585
 586static const struct file_operations u32_array_fops = {
 587        .owner   = THIS_MODULE,
 588        .open    = u32_array_open,
 589        .release = u32_array_release,
 590        .read    = u32_array_read,
 591        .llseek  = no_llseek,
 592};
 593
 594/**
 595 * debugfs_create_u32_array - create a debugfs file that is used to read u32
 596 * array.
 597 * @name: a pointer to a string containing the name of the file to create.
 598 * @mode: the permission that the file should have.
 599 * @parent: a pointer to the parent dentry for this file.  This should be a
 600 *          directory dentry if set.  If this parameter is %NULL, then the
 601 *          file will be created in the root of the debugfs filesystem.
 602 * @array: u32 array that provides data.
 603 * @elements: total number of elements in the array.
 604 *
 605 * This function creates a file in debugfs with the given name that exports
 606 * @array as data. If the @mode variable is so set it can be read from.
 607 * Writing is not supported. Seek within the file is also not supported.
 608 * Once array is created its size can not be changed.
 609 *
 610 * The function returns a pointer to dentry on success. If debugfs is not
 611 * enabled in the kernel, the value -%ENODEV will be returned.
 612 */
 613struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
 614                                            struct dentry *parent,
 615                                            u32 *array, u32 elements)
 616{
 617        struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
 618
 619        if (data == NULL)
 620                return NULL;
 621
 622        data->array = array;
 623        data->elements = elements;
 624
 625        return debugfs_create_file(name, mode, parent, data, &u32_array_fops);
 626}
 627EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
 628
 629#ifdef CONFIG_HAS_IOMEM
 630
 631/*
 632 * The regset32 stuff is used to print 32-bit registers using the
 633 * seq_file utilities. We offer printing a register set in an already-opened
 634 * sequential file or create a debugfs file that only prints a regset32.
 635 */
 636
 637/**
 638 * debugfs_print_regs32 - use seq_print to describe a set of registers
 639 * @s: the seq_file structure being used to generate output
 640 * @regs: an array if struct debugfs_reg32 structures
 641 * @nregs: the length of the above array
 642 * @base: the base address to be used in reading the registers
 643 * @prefix: a string to be prefixed to every output line
 644 *
 645 * This function outputs a text block describing the current values of
 646 * some 32-bit hardware registers. It is meant to be used within debugfs
 647 * files based on seq_file that need to show registers, intermixed with other
 648 * information. The prefix argument may be used to specify a leading string,
 649 * because some peripherals have several blocks of identical registers,
 650 * for example configuration of dma channels
 651 */
 652int debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
 653                           int nregs, void __iomem *base, char *prefix)
 654{
 655        int i, ret = 0;
 656
 657        for (i = 0; i < nregs; i++, regs++) {
 658                if (prefix)
 659                        ret += seq_printf(s, "%s", prefix);
 660                ret += seq_printf(s, "%s = 0x%08x\n", regs->name,
 661                                  readl(base + regs->offset));
 662        }
 663        return ret;
 664}
 665EXPORT_SYMBOL_GPL(debugfs_print_regs32);
 666
 667static int debugfs_show_regset32(struct seq_file *s, void *data)
 668{
 669        struct debugfs_regset32 *regset = s->private;
 670
 671        debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
 672        return 0;
 673}
 674
 675static int debugfs_open_regset32(struct inode *inode, struct file *file)
 676{
 677        return single_open(file, debugfs_show_regset32, inode->i_private);
 678}
 679
 680static const struct file_operations fops_regset32 = {
 681        .open =         debugfs_open_regset32,
 682        .read =         seq_read,
 683        .llseek =       seq_lseek,
 684        .release =      single_release,
 685};
 686
 687/**
 688 * debugfs_create_regset32 - create a debugfs file that returns register values
 689 * @name: a pointer to a string containing the name of the file to create.
 690 * @mode: the permission that the file should have
 691 * @parent: a pointer to the parent dentry for this file.  This should be a
 692 *          directory dentry if set.  If this parameter is %NULL, then the
 693 *          file will be created in the root of the debugfs filesystem.
 694 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
 695 *          to an array of register definitions, the array size and the base
 696 *          address where the register bank is to be found.
 697 *
 698 * This function creates a file in debugfs with the given name that reports
 699 * the names and values of a set of 32-bit registers. If the @mode variable
 700 * is so set it can be read from. Writing is not supported.
 701 *
 702 * This function will return a pointer to a dentry if it succeeds.  This
 703 * pointer must be passed to the debugfs_remove() function when the file is
 704 * to be removed (no automatic cleanup happens if your module is unloaded,
 705 * you are responsible here.)  If an error occurs, %NULL will be returned.
 706 *
 707 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 708 * returned.  It is not wise to check for this value, but rather, check for
 709 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 710 * code.
 711 */
 712struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
 713                                       struct dentry *parent,
 714                                       struct debugfs_regset32 *regset)
 715{
 716        return debugfs_create_file(name, mode, parent, regset, &fops_regset32);
 717}
 718EXPORT_SYMBOL_GPL(debugfs_create_regset32);
 719
 720#endif /* CONFIG_HAS_IOMEM */
 721
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