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#include <linux/atomic.h>
  25
  26static ssize_t default_read_file(struct file *file, char __user *buf,
  27                                 size_t count, loff_t *ppos)
  28{
  29        return 0;
  30}
  31
  32static ssize_t default_write_file(struct file *file, const char __user *buf,
  33                                   size_t count, loff_t *ppos)
  34{
  35        return count;
  36}
  37
  38const struct file_operations debugfs_file_operations = {
  39        .read =         default_read_file,
  40        .write =        default_write_file,
  41        .open =         simple_open,
  42        .llseek =       noop_llseek,
  43};
  44
  45static void *debugfs_follow_link(struct dentry *dentry, struct nameidata *nd)
  46{
  47        nd_set_link(nd, dentry->d_inode->i_private);
  48        return NULL;
  49}
  50
  51const struct inode_operations debugfs_link_operations = {
  52        .readlink       = generic_readlink,
  53        .follow_link    = debugfs_follow_link,
  54};
  55
  56static int debugfs_u8_set(void *data, u64 val)
  57{
  58        *(u8 *)data = val;
  59        return 0;
  60}
  61static int debugfs_u8_get(void *data, u64 *val)
  62{
  63        *val = *(u8 *)data;
  64        return 0;
  65}
  66DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
  67DEFINE_SIMPLE_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
  68DEFINE_SIMPLE_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
  69
  70/**
  71 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
  72 * @name: a pointer to a string containing the name of the file to create.
  73 * @mode: the permission that the file should have
  74 * @parent: a pointer to the parent dentry for this file.  This should be a
  75 *          directory dentry if set.  If this parameter is %NULL, then the
  76 *          file will be created in the root of the debugfs filesystem.
  77 * @value: a pointer to the variable that the file should read to and write
  78 *         from.
  79 *
  80 * This function creates a file in debugfs with the given name that
  81 * contains the value of the variable @value.  If the @mode variable is so
  82 * set, it can be read from, and written to.
  83 *
  84 * This function will return a pointer to a dentry if it succeeds.  This
  85 * pointer must be passed to the debugfs_remove() function when the file is
  86 * to be removed (no automatic cleanup happens if your module is unloaded,
  87 * you are responsible here.)  If an error occurs, %NULL will be returned.
  88 *
  89 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
  90 * returned.  It is not wise to check for this value, but rather, check for
  91 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
  92 * code.
  93 */
  94struct dentry *debugfs_create_u8(const char *name, umode_t mode,
  95                                 struct dentry *parent, u8 *value)
  96{
  97        /* if there are no write bits set, make read only */
  98        if (!(mode & S_IWUGO))
  99                return debugfs_create_file(name, mode, parent, value, &fops_u8_ro);
 100        /* if there are no read bits set, make write only */
 101        if (!(mode & S_IRUGO))
 102                return debugfs_create_file(name, mode, parent, value, &fops_u8_wo);
 103
 104        return debugfs_create_file(name, mode, parent, value, &fops_u8);
 105}
 106EXPORT_SYMBOL_GPL(debugfs_create_u8);
 107
 108static int debugfs_u16_set(void *data, u64 val)
 109{
 110        *(u16 *)data = val;
 111        return 0;
 112}
 113static int debugfs_u16_get(void *data, u64 *val)
 114{
 115        *val = *(u16 *)data;
 116        return 0;
 117}
 118DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
 119DEFINE_SIMPLE_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
 120DEFINE_SIMPLE_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
 121
 122/**
 123 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
 124 * @name: a pointer to a string containing the name of the file to create.
 125 * @mode: the permission that the file should have
 126 * @parent: a pointer to the parent dentry for this file.  This should be a
 127 *          directory dentry if set.  If this parameter is %NULL, then the
 128 *          file will be created in the root of the debugfs filesystem.
 129 * @value: a pointer to the variable that the file should read to and write
 130 *         from.
 131 *
 132 * This function creates a file in debugfs with the given name that
 133 * contains the value of the variable @value.  If the @mode variable is so
 134 * set, it can be read from, and written to.
 135 *
 136 * This function will return a pointer to a dentry if it succeeds.  This
 137 * pointer must be passed to the debugfs_remove() function when the file is
 138 * to be removed (no automatic cleanup happens if your module is unloaded,
 139 * you are responsible here.)  If an error occurs, %NULL will be returned.
 140 *
 141 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 142 * returned.  It is not wise to check for this value, but rather, check for
 143 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 144 * code.
 145 */
 146struct dentry *debugfs_create_u16(const char *name, umode_t mode,
 147                                  struct dentry *parent, u16 *value)
 148{
 149        /* if there are no write bits set, make read only */
 150        if (!(mode & S_IWUGO))
 151                return debugfs_create_file(name, mode, parent, value, &fops_u16_ro);
 152        /* if there are no read bits set, make write only */
 153        if (!(mode & S_IRUGO))
 154                return debugfs_create_file(name, mode, parent, value, &fops_u16_wo);
 155
 156        return debugfs_create_file(name, mode, parent, value, &fops_u16);
 157}
 158EXPORT_SYMBOL_GPL(debugfs_create_u16);
 159
 160static int debugfs_u32_set(void *data, u64 val)
 161{
 162        *(u32 *)data = val;
 163        return 0;
 164}
 165static int debugfs_u32_get(void *data, u64 *val)
 166{
 167        *val = *(u32 *)data;
 168        return 0;
 169}
 170DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
 171DEFINE_SIMPLE_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
 172DEFINE_SIMPLE_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
 173
 174/**
 175 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
 176 * @name: a pointer to a string containing the name of the file to create.
 177 * @mode: the permission that the file should have
 178 * @parent: a pointer to the parent dentry for this file.  This should be a
 179 *          directory dentry if set.  If this parameter is %NULL, then the
 180 *          file will be created in the root of the debugfs filesystem.
 181 * @value: a pointer to the variable that the file should read to and write
 182 *         from.
 183 *
 184 * This function creates a file in debugfs with the given name that
 185 * contains the value of the variable @value.  If the @mode variable is so
 186 * set, it can be read from, and written to.
 187 *
 188 * This function will return a pointer to a dentry if it succeeds.  This
 189 * pointer must be passed to the debugfs_remove() function when the file is
 190 * to be removed (no automatic cleanup happens if your module is unloaded,
 191 * you are responsible here.)  If an error occurs, %NULL will be returned.
 192 *
 193 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 194 * returned.  It is not wise to check for this value, but rather, check for
 195 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 196 * code.
 197 */
 198struct dentry *debugfs_create_u32(const char *name, umode_t mode,
 199                                 struct dentry *parent, u32 *value)
 200{
 201        /* if there are no write bits set, make read only */
 202        if (!(mode & S_IWUGO))
 203                return debugfs_create_file(name, mode, parent, value, &fops_u32_ro);
 204        /* if there are no read bits set, make write only */
 205        if (!(mode & S_IRUGO))
 206                return debugfs_create_file(name, mode, parent, value, &fops_u32_wo);
 207
 208        return debugfs_create_file(name, mode, parent, value, &fops_u32);
 209}
 210EXPORT_SYMBOL_GPL(debugfs_create_u32);
 211
 212static int debugfs_u64_set(void *data, u64 val)
 213{
 214        *(u64 *)data = val;
 215        return 0;
 216}
 217
 218static int debugfs_u64_get(void *data, u64 *val)
 219{
 220        *val = *(u64 *)data;
 221        return 0;
 222}
 223DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
 224DEFINE_SIMPLE_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
 225DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
 226
 227/**
 228 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
 229 * @name: a pointer to a string containing the name of the file to create.
 230 * @mode: the permission that the file should have
 231 * @parent: a pointer to the parent dentry for this file.  This should be a
 232 *          directory dentry if set.  If this parameter is %NULL, then the
 233 *          file will be created in the root of the debugfs filesystem.
 234 * @value: a pointer to the variable that the file should read to and write
 235 *         from.
 236 *
 237 * This function creates a file in debugfs with the given name that
 238 * contains the value of the variable @value.  If the @mode variable is so
 239 * set, it can be read from, and written to.
 240 *
 241 * This function will return a pointer to a dentry if it succeeds.  This
 242 * pointer must be passed to the debugfs_remove() function when the file is
 243 * to be removed (no automatic cleanup happens if your module is unloaded,
 244 * you are responsible here.)  If an error occurs, %NULL will be returned.
 245 *
 246 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 247 * returned.  It is not wise to check for this value, but rather, check for
 248 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 249 * code.
 250 */
 251struct dentry *debugfs_create_u64(const char *name, umode_t mode,
 252                                 struct dentry *parent, u64 *value)
 253{
 254        /* if there are no write bits set, make read only */
 255        if (!(mode & S_IWUGO))
 256                return debugfs_create_file(name, mode, parent, value, &fops_u64_ro);
 257        /* if there are no read bits set, make write only */
 258        if (!(mode & S_IRUGO))
 259                return debugfs_create_file(name, mode, parent, value, &fops_u64_wo);
 260
 261        return debugfs_create_file(name, mode, parent, value, &fops_u64);
 262}
 263EXPORT_SYMBOL_GPL(debugfs_create_u64);
 264
 265DEFINE_SIMPLE_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
 266DEFINE_SIMPLE_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
 267DEFINE_SIMPLE_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
 268
 269DEFINE_SIMPLE_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set, "0x%04llx\n");
 270DEFINE_SIMPLE_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
 271DEFINE_SIMPLE_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
 272
 273DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%08llx\n");
 274DEFINE_SIMPLE_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
 275DEFINE_SIMPLE_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
 276
 277DEFINE_SIMPLE_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set, "0x%016llx\n");
 278
 279/*
 280 * 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
 281 *
 282 * These functions are exactly the same as the above functions (but use a hex
 283 * output for the decimal challenged). For details look at the above unsigned
 284 * decimal functions.
 285 */
 286
 287/**
 288 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
 289 * @name: a pointer to a string containing the name of the file to create.
 290 * @mode: the permission that the file should have
 291 * @parent: a pointer to the parent dentry for this file.  This should be a
 292 *          directory dentry if set.  If this parameter is %NULL, then the
 293 *          file will be created in the root of the debugfs filesystem.
 294 * @value: a pointer to the variable that the file should read to and write
 295 *         from.
 296 */
 297struct dentry *debugfs_create_x8(const char *name, umode_t mode,
 298                                 struct dentry *parent, u8 *value)
 299{
 300        /* if there are no write bits set, make read only */
 301        if (!(mode & S_IWUGO))
 302                return debugfs_create_file(name, mode, parent, value, &fops_x8_ro);
 303        /* if there are no read bits set, make write only */
 304        if (!(mode & S_IRUGO))
 305                return debugfs_create_file(name, mode, parent, value, &fops_x8_wo);
 306
 307        return debugfs_create_file(name, mode, parent, value, &fops_x8);
 308}
 309EXPORT_SYMBOL_GPL(debugfs_create_x8);
 310
 311/**
 312 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
 313 * @name: a pointer to a string containing the name of the file to create.
 314 * @mode: the permission that the file should have
 315 * @parent: a pointer to the parent dentry for this file.  This should be a
 316 *          directory dentry if set.  If this parameter is %NULL, then the
 317 *          file will be created in the root of the debugfs filesystem.
 318 * @value: a pointer to the variable that the file should read to and write
 319 *         from.
 320 */
 321struct dentry *debugfs_create_x16(const char *name, umode_t mode,
 322                                 struct dentry *parent, u16 *value)
 323{
 324        /* if there are no write bits set, make read only */
 325        if (!(mode & S_IWUGO))
 326                return debugfs_create_file(name, mode, parent, value, &fops_x16_ro);
 327        /* if there are no read bits set, make write only */
 328        if (!(mode & S_IRUGO))
 329                return debugfs_create_file(name, mode, parent, value, &fops_x16_wo);
 330
 331        return debugfs_create_file(name, mode, parent, value, &fops_x16);
 332}
 333EXPORT_SYMBOL_GPL(debugfs_create_x16);
 334
 335/**
 336 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
 337 * @name: a pointer to a string containing the name of the file to create.
 338 * @mode: the permission that the file should have
 339 * @parent: a pointer to the parent dentry for this file.  This should be a
 340 *          directory dentry if set.  If this parameter is %NULL, then the
 341 *          file will be created in the root of the debugfs filesystem.
 342 * @value: a pointer to the variable that the file should read to and write
 343 *         from.
 344 */
 345struct dentry *debugfs_create_x32(const char *name, umode_t mode,
 346                                 struct dentry *parent, u32 *value)
 347{
 348        /* if there are no write bits set, make read only */
 349        if (!(mode & S_IWUGO))
 350                return debugfs_create_file(name, mode, parent, value, &fops_x32_ro);
 351        /* if there are no read bits set, make write only */
 352        if (!(mode & S_IRUGO))
 353                return debugfs_create_file(name, mode, parent, value, &fops_x32_wo);
 354
 355        return debugfs_create_file(name, mode, parent, value, &fops_x32);
 356}
 357EXPORT_SYMBOL_GPL(debugfs_create_x32);
 358
 359/**
 360 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
 361 * @name: a pointer to a string containing the name of the file to create.
 362 * @mode: the permission that the file should have
 363 * @parent: a pointer to the parent dentry for this file.  This should be a
 364 *          directory dentry if set.  If this parameter is %NULL, then the
 365 *          file will be created in the root of the debugfs filesystem.
 366 * @value: a pointer to the variable that the file should read to and write
 367 *         from.
 368 */
 369struct dentry *debugfs_create_x64(const char *name, umode_t mode,
 370                                 struct dentry *parent, u64 *value)
 371{
 372        return debugfs_create_file(name, mode, parent, value, &fops_x64);
 373}
 374EXPORT_SYMBOL_GPL(debugfs_create_x64);
 375
 376
 377static int debugfs_size_t_set(void *data, u64 val)
 378{
 379        *(size_t *)data = val;
 380        return 0;
 381}
 382static int debugfs_size_t_get(void *data, u64 *val)
 383{
 384        *val = *(size_t *)data;
 385        return 0;
 386}
 387DEFINE_SIMPLE_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
 388                        "%llu\n");      /* %llu and %zu are more or less the same */
 389
 390/**
 391 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
 392 * @name: a pointer to a string containing the name of the file to create.
 393 * @mode: the permission that the file should have
 394 * @parent: a pointer to the parent dentry for this file.  This should be a
 395 *          directory dentry if set.  If this parameter is %NULL, then the
 396 *          file will be created in the root of the debugfs filesystem.
 397 * @value: a pointer to the variable that the file should read to and write
 398 *         from.
 399 */
 400struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
 401                                     struct dentry *parent, size_t *value)
 402{
 403        return debugfs_create_file(name, mode, parent, value, &fops_size_t);
 404}
 405EXPORT_SYMBOL_GPL(debugfs_create_size_t);
 406
 407static int debugfs_atomic_t_set(void *data, u64 val)
 408{
 409        atomic_set((atomic_t *)data, val);
 410        return 0;
 411}
 412static int debugfs_atomic_t_get(void *data, u64 *val)
 413{
 414        *val = atomic_read((atomic_t *)data);
 415        return 0;
 416}
 417DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
 418                        debugfs_atomic_t_set, "%lld\n");
 419DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL, "%lld\n");
 420DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set, "%lld\n");
 421
 422/**
 423 * debugfs_create_atomic_t - create a debugfs file that is used to read and
 424 * write an atomic_t value
 425 * @name: a pointer to a string containing the name of the file to create.
 426 * @mode: the permission that the file should have
 427 * @parent: a pointer to the parent dentry for this file.  This should be a
 428 *          directory dentry if set.  If this parameter is %NULL, then the
 429 *          file will be created in the root of the debugfs filesystem.
 430 * @value: a pointer to the variable that the file should read to and write
 431 *         from.
 432 */
 433struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
 434                                 struct dentry *parent, atomic_t *value)
 435{
 436        /* if there are no write bits set, make read only */
 437        if (!(mode & S_IWUGO))
 438                return debugfs_create_file(name, mode, parent, value,
 439                                        &fops_atomic_t_ro);
 440        /* if there are no read bits set, make write only */
 441        if (!(mode & S_IRUGO))
 442                return debugfs_create_file(name, mode, parent, value,
 443                                        &fops_atomic_t_wo);
 444
 445        return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
 446}
 447EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
 448
 449static ssize_t read_file_bool(struct file *file, char __user *user_buf,
 450                              size_t count, loff_t *ppos)
 451{
 452        char buf[3];
 453        u32 *val = file->private_data;
 454        
 455        if (*val)
 456                buf[0] = 'Y';
 457        else
 458                buf[0] = 'N';
 459        buf[1] = '\n';
 460        buf[2] = 0x00;
 461        return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
 462}
 463
 464static ssize_t write_file_bool(struct file *file, const char __user *user_buf,
 465                               size_t count, loff_t *ppos)
 466{
 467        char buf[32];
 468        size_t buf_size;
 469        bool bv;
 470        u32 *val = file->private_data;
 471
 472        buf_size = min(count, (sizeof(buf)-1));
 473        if (copy_from_user(buf, user_buf, buf_size))
 474                return -EFAULT;
 475
 476        buf[buf_size] = '\0';
 477        if (strtobool(buf, &bv) == 0)
 478                *val = bv;
 479
 480        return count;
 481}
 482
 483static const struct file_operations fops_bool = {
 484        .read =         read_file_bool,
 485        .write =        write_file_bool,
 486        .open =         simple_open,
 487        .llseek =       default_llseek,
 488};
 489
 490/**
 491 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
 492 * @name: a pointer to a string containing the name of the file to create.
 493 * @mode: the permission that the file should have
 494 * @parent: a pointer to the parent dentry for this file.  This should be a
 495 *          directory dentry if set.  If this parameter is %NULL, then the
 496 *          file will be created in the root of the debugfs filesystem.
 497 * @value: a pointer to the variable that the file should read to and write
 498 *         from.
 499 *
 500 * This function creates a file in debugfs with the given name that
 501 * contains the value of the variable @value.  If the @mode variable is so
 502 * set, it can be read from, and written to.
 503 *
 504 * This function will return a pointer to a dentry if it succeeds.  This
 505 * pointer must be passed to the debugfs_remove() function when the file is
 506 * to be removed (no automatic cleanup happens if your module is unloaded,
 507 * you are responsible here.)  If an error occurs, %NULL will be returned.
 508 *
 509 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 510 * returned.  It is not wise to check for this value, but rather, check for
 511 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 512 * code.
 513 */
 514struct dentry *debugfs_create_bool(const char *name, umode_t mode,
 515                                   struct dentry *parent, u32 *value)
 516{
 517        return debugfs_create_file(name, mode, parent, value, &fops_bool);
 518}
 519EXPORT_SYMBOL_GPL(debugfs_create_bool);
 520
 521static ssize_t read_file_blob(struct file *file, char __user *user_buf,
 522                              size_t count, loff_t *ppos)
 523{
 524        struct debugfs_blob_wrapper *blob = file->private_data;
 525        return simple_read_from_buffer(user_buf, count, ppos, blob->data,
 526                        blob->size);
 527}
 528
 529static const struct file_operations fops_blob = {
 530        .read =         read_file_blob,
 531        .open =         simple_open,
 532        .llseek =       default_llseek,
 533};
 534
 535/**
 536 * debugfs_create_blob - create a debugfs file that is used to read a binary blob
 537 * @name: a pointer to a string containing the name of the file to create.
 538 * @mode: the permission that the file should have
 539 * @parent: a pointer to the parent dentry for this file.  This should be a
 540 *          directory dentry if set.  If this parameter is %NULL, then the
 541 *          file will be created in the root of the debugfs filesystem.
 542 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
 543 *        to the blob data and the size of the data.
 544 *
 545 * This function creates a file in debugfs with the given name that exports
 546 * @blob->data as a binary blob. If the @mode variable is so set it can be
 547 * read from. Writing is not supported.
 548 *
 549 * This function will return a pointer to a dentry if it succeeds.  This
 550 * pointer must be passed to the debugfs_remove() function when the file is
 551 * to be removed (no automatic cleanup happens if your module is unloaded,
 552 * you are responsible here.)  If an error occurs, %NULL will be returned.
 553 *
 554 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 555 * returned.  It is not wise to check for this value, but rather, check for
 556 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 557 * code.
 558 */
 559struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 560                                   struct dentry *parent,
 561                                   struct debugfs_blob_wrapper *blob)
 562{
 563        return debugfs_create_file(name, mode, parent, blob, &fops_blob);
 564}
 565EXPORT_SYMBOL_GPL(debugfs_create_blob);
 566
 567struct array_data {
 568        void *array;
 569        u32 elements;
 570};
 571
 572static size_t u32_format_array(char *buf, size_t bufsize,
 573                               u32 *array, int array_size)
 574{
 575        size_t ret = 0;
 576
 577        while (--array_size >= 0) {
 578                size_t len;
 579                char term = array_size ? ' ' : '\n';
 580
 581                len = snprintf(buf, bufsize, "%u%c", *array++, term);
 582                ret += len;
 583
 584                buf += len;
 585                bufsize -= len;
 586        }
 587        return ret;
 588}
 589
 590static int u32_array_open(struct inode *inode, struct file *file)
 591{
 592        struct array_data *data = inode->i_private;
 593        int size, elements = data->elements;
 594        char *buf;
 595
 596        /*
 597         * Max size:
 598         *  - 10 digits + ' '/'\n' = 11 bytes per number
 599         *  - terminating NUL character
 600         */
 601        size = elements*11;
 602        buf = kmalloc(size+1, GFP_KERNEL);
 603        if (!buf)
 604                return -ENOMEM;
 605        buf[size] = 0;
 606
 607        file->private_data = buf;
 608        u32_format_array(buf, size, data->array, data->elements);
 609
 610        return nonseekable_open(inode, file);
 611}
 612
 613static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
 614                              loff_t *ppos)
 615{
 616        size_t size = strlen(file->private_data);
 617
 618        return simple_read_from_buffer(buf, len, ppos,
 619                                        file->private_data, size);
 620}
 621
 622static int u32_array_release(struct inode *inode, struct file *file)
 623{
 624        kfree(file->private_data);
 625
 626        return 0;
 627}
 628
 629static const struct file_operations u32_array_fops = {
 630        .owner   = THIS_MODULE,
 631        .open    = u32_array_open,
 632        .release = u32_array_release,
 633        .read    = u32_array_read,
 634        .llseek  = no_llseek,
 635};
 636
 637/**
 638 * debugfs_create_u32_array - create a debugfs file that is used to read u32
 639 * array.
 640 * @name: a pointer to a string containing the name of the file to create.
 641 * @mode: the permission that the file should have.
 642 * @parent: a pointer to the parent dentry for this file.  This should be a
 643 *          directory dentry if set.  If this parameter is %NULL, then the
 644 *          file will be created in the root of the debugfs filesystem.
 645 * @array: u32 array that provides data.
 646 * @elements: total number of elements in the array.
 647 *
 648 * This function creates a file in debugfs with the given name that exports
 649 * @array as data. If the @mode variable is so set it can be read from.
 650 * Writing is not supported. Seek within the file is also not supported.
 651 * Once array is created its size can not be changed.
 652 *
 653 * The function returns a pointer to dentry on success. If debugfs is not
 654 * enabled in the kernel, the value -%ENODEV will be returned.
 655 */
 656struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
 657                                            struct dentry *parent,
 658                                            u32 *array, u32 elements)
 659{
 660        struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
 661
 662        if (data == NULL)
 663                return NULL;
 664
 665        data->array = array;
 666        data->elements = elements;
 667
 668        return debugfs_create_file(name, mode, parent, data, &u32_array_fops);
 669}
 670EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
 671
 672#ifdef CONFIG_HAS_IOMEM
 673
 674/*
 675 * The regset32 stuff is used to print 32-bit registers using the
 676 * seq_file utilities. We offer printing a register set in an already-opened
 677 * sequential file or create a debugfs file that only prints a regset32.
 678 */
 679
 680/**
 681 * debugfs_print_regs32 - use seq_print to describe a set of registers
 682 * @s: the seq_file structure being used to generate output
 683 * @regs: an array if struct debugfs_reg32 structures
 684 * @nregs: the length of the above array
 685 * @base: the base address to be used in reading the registers
 686 * @prefix: a string to be prefixed to every output line
 687 *
 688 * This function outputs a text block describing the current values of
 689 * some 32-bit hardware registers. It is meant to be used within debugfs
 690 * files based on seq_file that need to show registers, intermixed with other
 691 * information. The prefix argument may be used to specify a leading string,
 692 * because some peripherals have several blocks of identical registers,
 693 * for example configuration of dma channels
 694 */
 695int debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
 696                           int nregs, void __iomem *base, char *prefix)
 697{
 698        int i, ret = 0;
 699
 700        for (i = 0; i < nregs; i++, regs++) {
 701                if (prefix)
 702                        ret += seq_printf(s, "%s", prefix);
 703                ret += seq_printf(s, "%s = 0x%08x\n", regs->name,
 704                                  readl(base + regs->offset));
 705        }
 706        return ret;
 707}
 708EXPORT_SYMBOL_GPL(debugfs_print_regs32);
 709
 710static int debugfs_show_regset32(struct seq_file *s, void *data)
 711{
 712        struct debugfs_regset32 *regset = s->private;
 713
 714        debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
 715        return 0;
 716}
 717
 718static int debugfs_open_regset32(struct inode *inode, struct file *file)
 719{
 720        return single_open(file, debugfs_show_regset32, inode->i_private);
 721}
 722
 723static const struct file_operations fops_regset32 = {
 724        .open =         debugfs_open_regset32,
 725        .read =         seq_read,
 726        .llseek =       seq_lseek,
 727        .release =      single_release,
 728};
 729
 730/**
 731 * debugfs_create_regset32 - create a debugfs file that returns register values
 732 * @name: a pointer to a string containing the name of the file to create.
 733 * @mode: the permission that the file should have
 734 * @parent: a pointer to the parent dentry for this file.  This should be a
 735 *          directory dentry if set.  If this parameter is %NULL, then the
 736 *          file will be created in the root of the debugfs filesystem.
 737 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
 738 *          to an array of register definitions, the array size and the base
 739 *          address where the register bank is to be found.
 740 *
 741 * This function creates a file in debugfs with the given name that reports
 742 * the names and values of a set of 32-bit registers. If the @mode variable
 743 * is so set it can be read from. Writing is not supported.
 744 *
 745 * This function will return a pointer to a dentry if it succeeds.  This
 746 * pointer must be passed to the debugfs_remove() function when the file is
 747 * to be removed (no automatic cleanup happens if your module is unloaded,
 748 * you are responsible here.)  If an error occurs, %NULL will be returned.
 749 *
 750 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 751 * returned.  It is not wise to check for this value, but rather, check for
 752 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
 753 * code.
 754 */
 755struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
 756                                       struct dentry *parent,
 757                                       struct debugfs_regset32 *regset)
 758{
 759        return debugfs_create_file(name, mode, parent, regset, &fops_regset32);
 760}
 761EXPORT_SYMBOL_GPL(debugfs_create_regset32);
 762
 763#endif /* CONFIG_HAS_IOMEM */
 764
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