/*
   *  file.c - part of debugfs, a tiny little debug file system
   *
   *  Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
   *  Copyright (C) 2004 IBM Inc.
   *
   *	This program is free software; you can redistribute it and/or
   *	modify it under the terms of the GNU General Public License version
   *	2 as published by the Free Software Foundation.
   *
   *  debugfs is for people to use instead of /proc or /sys.

   *  See Documentation/DocBook/filesystems for more details.

   *
   */

  #include <linux/module.h>
  #include <linux/fs.h>

  #include <linux/seq_file.h>

  #include <linux/pagemap.h>
  #include <linux/debugfs.h>

  #include <linux/io.h>

  #include <linux/slab.h>

  #include <linux/atomic.h>

  #include <linux/device.h>

  
  static ssize_t default_read_file(struct file *file, char __user *buf,
  				 size_t count, loff_t *ppos)
  {
  	return 0;
  }
  
  static ssize_t default_write_file(struct file *file, const char __user *buf,
  				   size_t count, loff_t *ppos)
  {
  	return count;
  }

  const struct file_operations debugfs_file_operations = {

  	.read =		default_read_file,
  	.write =	default_write_file,

  	.open =		simple_open,

  	.llseek =	noop_llseek,

  };

  static struct dentry *debugfs_create_mode(const char *name, umode_t mode,
  					  struct dentry *parent, void *value,
  				          const struct file_operations *fops,
  				          const struct file_operations *fops_ro,
  				          const struct file_operations *fops_wo)
  {
  	/* if there are no write bits set, make read only */
  	if (!(mode & S_IWUGO))
  		return debugfs_create_file(name, mode, parent, value, fops_ro);
  	/* if there are no read bits set, make write only */
  	if (!(mode & S_IRUGO))
  		return debugfs_create_file(name, mode, parent, value, fops_wo);
  
  	return debugfs_create_file(name, mode, parent, value, fops);
  }

  static int debugfs_u8_set(void *data, u64 val)

  {
  	*(u8 *)data = val;

  	return 0;

  }

  static int debugfs_u8_get(void *data, u64 *val)

  {

  	*val = *(u8 *)data;
  	return 0;

  }
  DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu
  ");

  DEFINE_SIMPLE_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu
  ");

  
  /**

   * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value

   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a

   *          directory dentry if set.  If this parameter is %NULL, then the

   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   *
   * This function creates a file in debugfs with the given name that
   * contains the value of the variable @value.  If the @mode variable is so
   * set, it can be read from, and written to.
   *
   * This function will return a pointer to a dentry if it succeeds.  This
   * pointer must be passed to the debugfs_remove() function when the file is
   * to be removed (no automatic cleanup happens if your module is unloaded,

   * you are responsible here.)  If an error occurs, %NULL will be returned.

   *

   * If debugfs is not enabled in the kernel, the value -%ENODEV will be

   * returned.  It is not wise to check for this value, but rather, check for

   * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling

   * code.
   */

  struct dentry *debugfs_create_u8(const char *name, umode_t mode,

  				 struct dentry *parent, u8 *value)
  {

  	return debugfs_create_mode(name, mode, parent, value, &fops_u8,
  				   &fops_u8_ro, &fops_u8_wo);

  }
  EXPORT_SYMBOL_GPL(debugfs_create_u8);

  static int debugfs_u16_set(void *data, u64 val)

  {
  	*(u16 *)data = val;

  	return 0;

  }

  static int debugfs_u16_get(void *data, u64 *val)

  {

  	*val = *(u16 *)data;
  	return 0;

  }
  DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu
  ");

  DEFINE_SIMPLE_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu
  ");

  /**

   * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value

   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a

   *          directory dentry if set.  If this parameter is %NULL, then the

   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   *
   * This function creates a file in debugfs with the given name that
   * contains the value of the variable @value.  If the @mode variable is so
   * set, it can be read from, and written to.
   *
   * This function will return a pointer to a dentry if it succeeds.  This
   * pointer must be passed to the debugfs_remove() function when the file is
   * to be removed (no automatic cleanup happens if your module is unloaded,

   * you are responsible here.)  If an error occurs, %NULL will be returned.

   *

   * If debugfs is not enabled in the kernel, the value -%ENODEV will be

   * returned.  It is not wise to check for this value, but rather, check for

   * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling

   * code.
   */

  struct dentry *debugfs_create_u16(const char *name, umode_t mode,

  				  struct dentry *parent, u16 *value)
  {

  	return debugfs_create_mode(name, mode, parent, value, &fops_u16,
  				   &fops_u16_ro, &fops_u16_wo);

  }
  EXPORT_SYMBOL_GPL(debugfs_create_u16);

  static int debugfs_u32_set(void *data, u64 val)

  {
  	*(u32 *)data = val;

  	return 0;

  }

  static int debugfs_u32_get(void *data, u64 *val)

  {

  	*val = *(u32 *)data;
  	return 0;

  }
  DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu
  ");

  DEFINE_SIMPLE_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu
  ");

  /**

   * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value

   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a

   *          directory dentry if set.  If this parameter is %NULL, then the

   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   *
   * This function creates a file in debugfs with the given name that
   * contains the value of the variable @value.  If the @mode variable is so
   * set, it can be read from, and written to.
   *
   * This function will return a pointer to a dentry if it succeeds.  This
   * pointer must be passed to the debugfs_remove() function when the file is
   * to be removed (no automatic cleanup happens if your module is unloaded,

   * you are responsible here.)  If an error occurs, %NULL will be returned.

   *

   * If debugfs is not enabled in the kernel, the value -%ENODEV will be

   * returned.  It is not wise to check for this value, but rather, check for

   * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling

   * code.
   */

  struct dentry *debugfs_create_u32(const char *name, umode_t mode,

  				 struct dentry *parent, u32 *value)
  {

  	return debugfs_create_mode(name, mode, parent, value, &fops_u32,
  				   &fops_u32_ro, &fops_u32_wo);

  }
  EXPORT_SYMBOL_GPL(debugfs_create_u32);

  static int debugfs_u64_set(void *data, u64 val)

  {
  	*(u64 *)data = val;

  	return 0;

  }

  static int debugfs_u64_get(void *data, u64 *val)

  {

  	*val = *(u64 *)data;
  	return 0;

  }
  DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu
  ");

  DEFINE_SIMPLE_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu
  ");

  
  /**
   * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a
   *          directory dentry if set.  If this parameter is %NULL, then the
   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   *
   * This function creates a file in debugfs with the given name that
   * contains the value of the variable @value.  If the @mode variable is so
   * set, it can be read from, and written to.
   *
   * This function will return a pointer to a dentry if it succeeds.  This
   * pointer must be passed to the debugfs_remove() function when the file is
   * to be removed (no automatic cleanup happens if your module is unloaded,
   * you are responsible here.)  If an error occurs, %NULL will be returned.
   *
   * If debugfs is not enabled in the kernel, the value -%ENODEV will be
   * returned.  It is not wise to check for this value, but rather, check for
   * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
   * code.
   */

  struct dentry *debugfs_create_u64(const char *name, umode_t mode,

  				 struct dentry *parent, u64 *value)
  {

  	return debugfs_create_mode(name, mode, parent, value, &fops_u64,
  				   &fops_u64_ro, &fops_u64_wo);

  }
  EXPORT_SYMBOL_GPL(debugfs_create_u64);

  static int debugfs_ulong_set(void *data, u64 val)
  {
  	*(unsigned long *)data = val;
  	return 0;
  }
  
  static int debugfs_ulong_get(void *data, u64 *val)
  {
  	*val = *(unsigned long *)data;
  	return 0;
  }
  DEFINE_SIMPLE_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set, "%llu
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu
  ");
  
  /**
   * debugfs_create_ulong - create a debugfs file that is used to read and write
   * an unsigned long value.
   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a
   *          directory dentry if set.  If this parameter is %NULL, then the
   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   *
   * This function creates a file in debugfs with the given name that
   * contains the value of the variable @value.  If the @mode variable is so
   * set, it can be read from, and written to.
   *
   * This function will return a pointer to a dentry if it succeeds.  This
   * pointer must be passed to the debugfs_remove() function when the file is
   * to be removed (no automatic cleanup happens if your module is unloaded,
   * you are responsible here.)  If an error occurs, %NULL will be returned.
   *
   * If debugfs is not enabled in the kernel, the value -%ENODEV will be
   * returned.  It is not wise to check for this value, but rather, check for
   * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
   * code.
   */
  struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
  				    struct dentry *parent, unsigned long *value)
  {
  	return debugfs_create_mode(name, mode, parent, value, &fops_ulong,
  				   &fops_ulong_ro, &fops_ulong_wo);
  }
  EXPORT_SYMBOL_GPL(debugfs_create_ulong);

  DEFINE_SIMPLE_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx
  ");

  DEFINE_SIMPLE_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx
  ");

  
  DEFINE_SIMPLE_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set, "0x%04llx
  ");

  DEFINE_SIMPLE_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx
  ");

  
  DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%08llx
  ");

  DEFINE_SIMPLE_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx
  ");

  DEFINE_SIMPLE_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set, "0x%016llx
  ");

  DEFINE_SIMPLE_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx
  ");

  /*

   * 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

   *

   * These functions are exactly the same as the above functions (but use a hex
   * output for the decimal challenged). For details look at the above unsigned

   * decimal functions.
   */

  
  /**
   * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a
   *          directory dentry if set.  If this parameter is %NULL, then the
   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   */

  struct dentry *debugfs_create_x8(const char *name, umode_t mode,

  				 struct dentry *parent, u8 *value)
  {

  	return debugfs_create_mode(name, mode, parent, value, &fops_x8,
  				   &fops_x8_ro, &fops_x8_wo);

  }
  EXPORT_SYMBOL_GPL(debugfs_create_x8);

  /**
   * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a
   *          directory dentry if set.  If this parameter is %NULL, then the
   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   */

  struct dentry *debugfs_create_x16(const char *name, umode_t mode,

  				 struct dentry *parent, u16 *value)
  {

  	return debugfs_create_mode(name, mode, parent, value, &fops_x16,
  				   &fops_x16_ro, &fops_x16_wo);

  }
  EXPORT_SYMBOL_GPL(debugfs_create_x16);

  /**
   * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a
   *          directory dentry if set.  If this parameter is %NULL, then the
   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   */

  struct dentry *debugfs_create_x32(const char *name, umode_t mode,

  				 struct dentry *parent, u32 *value)
  {

  	return debugfs_create_mode(name, mode, parent, value, &fops_x32,
  				   &fops_x32_ro, &fops_x32_wo);

  }
  EXPORT_SYMBOL_GPL(debugfs_create_x32);

  /**
   * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a
   *          directory dentry if set.  If this parameter is %NULL, then the
   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   */

  struct dentry *debugfs_create_x64(const char *name, umode_t mode,

  				 struct dentry *parent, u64 *value)
  {

  	return debugfs_create_mode(name, mode, parent, value, &fops_x64,
  				   &fops_x64_ro, &fops_x64_wo);

  }
  EXPORT_SYMBOL_GPL(debugfs_create_x64);

  
  static int debugfs_size_t_set(void *data, u64 val)
  {
  	*(size_t *)data = val;
  	return 0;
  }
  static int debugfs_size_t_get(void *data, u64 *val)
  {
  	*val = *(size_t *)data;
  	return 0;
  }
  DEFINE_SIMPLE_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
  			"%llu
  ");	/* %llu and %zu are more or less the same */

  DEFINE_SIMPLE_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu
  ");

  
  /**
   * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a
   *          directory dentry if set.  If this parameter is %NULL, then the
   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   */

  struct dentry *debugfs_create_size_t(const char *name, umode_t mode,

  				     struct dentry *parent, size_t *value)
  {

  	return debugfs_create_mode(name, mode, parent, value, &fops_size_t,
  				   &fops_size_t_ro, &fops_size_t_wo);

  }
  EXPORT_SYMBOL_GPL(debugfs_create_size_t);

  static int debugfs_atomic_t_set(void *data, u64 val)
  {
  	atomic_set((atomic_t *)data, val);
  	return 0;
  }
  static int debugfs_atomic_t_get(void *data, u64 *val)
  {
  	*val = atomic_read((atomic_t *)data);
  	return 0;
  }
  DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
  			debugfs_atomic_t_set, "%lld
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL, "%lld
  ");
  DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set, "%lld
  ");
  
  /**
   * debugfs_create_atomic_t - create a debugfs file that is used to read and
   * write an atomic_t value
   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a
   *          directory dentry if set.  If this parameter is %NULL, then the
   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   */
  struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
  				 struct dentry *parent, atomic_t *value)
  {

  	return debugfs_create_mode(name, mode, parent, value, &fops_atomic_t,
  				   &fops_atomic_t_ro, &fops_atomic_t_wo);

  }
  EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);

  ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
  			       size_t count, loff_t *ppos)

  {
  	char buf[3];

  	bool *val = file->private_data;

  	if (*val)
  		buf[0] = 'Y';
  	else
  		buf[0] = 'N';
  	buf[1] = '
  ';
  	buf[2] = 0x00;
  	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
  }

  EXPORT_SYMBOL_GPL(debugfs_read_file_bool);

  ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
  				size_t count, loff_t *ppos)

  {
  	char buf[32];

  	size_t buf_size;

  	bool bv;

  	bool *val = file->private_data;

  
  	buf_size = min(count, (sizeof(buf)-1));
  	if (copy_from_user(buf, user_buf, buf_size))
  		return -EFAULT;

  	buf[buf_size] = '\0';

  	if (strtobool(buf, &bv) == 0)
  		*val = bv;

  	return count;
  }

  EXPORT_SYMBOL_GPL(debugfs_write_file_bool);

  static const struct file_operations fops_bool = {

  	.read =		debugfs_read_file_bool,
  	.write =	debugfs_write_file_bool,

  	.open =		simple_open,

  	.llseek =	default_llseek,

  };

  static const struct file_operations fops_bool_ro = {
  	.read =		debugfs_read_file_bool,
  	.open =		simple_open,
  	.llseek =	default_llseek,
  };
  
  static const struct file_operations fops_bool_wo = {
  	.write =	debugfs_write_file_bool,
  	.open =		simple_open,
  	.llseek =	default_llseek,
  };

  /**

   * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value

   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a

   *          directory dentry if set.  If this parameter is %NULL, then the

   *          file will be created in the root of the debugfs filesystem.
   * @value: a pointer to the variable that the file should read to and write
   *         from.
   *
   * This function creates a file in debugfs with the given name that
   * contains the value of the variable @value.  If the @mode variable is so
   * set, it can be read from, and written to.
   *
   * This function will return a pointer to a dentry if it succeeds.  This
   * pointer must be passed to the debugfs_remove() function when the file is
   * to be removed (no automatic cleanup happens if your module is unloaded,

   * you are responsible here.)  If an error occurs, %NULL will be returned.

   *

   * If debugfs is not enabled in the kernel, the value -%ENODEV will be

   * returned.  It is not wise to check for this value, but rather, check for

   * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling

   * code.
   */

  struct dentry *debugfs_create_bool(const char *name, umode_t mode,

  				   struct dentry *parent, bool *value)

  {

  	return debugfs_create_mode(name, mode, parent, value, &fops_bool,
  				   &fops_bool_ro, &fops_bool_wo);

  }
  EXPORT_SYMBOL_GPL(debugfs_create_bool);

  static ssize_t read_file_blob(struct file *file, char __user *user_buf,
  			      size_t count, loff_t *ppos)
  {
  	struct debugfs_blob_wrapper *blob = file->private_data;
  	return simple_read_from_buffer(user_buf, count, ppos, blob->data,
  			blob->size);
  }

  static const struct file_operations fops_blob = {

  	.read =		read_file_blob,

  	.open =		simple_open,

  	.llseek =	default_llseek,

  };
  
  /**

   * debugfs_create_blob - create a debugfs file that is used to read a binary blob

   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a

   *          directory dentry if set.  If this parameter is %NULL, then the

   *          file will be created in the root of the debugfs filesystem.
   * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
   *        to the blob data and the size of the data.
   *
   * This function creates a file in debugfs with the given name that exports
   * @blob->data as a binary blob. If the @mode variable is so set it can be
   * read from. Writing is not supported.
   *
   * This function will return a pointer to a dentry if it succeeds.  This
   * pointer must be passed to the debugfs_remove() function when the file is
   * to be removed (no automatic cleanup happens if your module is unloaded,

   * you are responsible here.)  If an error occurs, %NULL will be returned.

   *

   * If debugfs is not enabled in the kernel, the value -%ENODEV will be

   * returned.  It is not wise to check for this value, but rather, check for

   * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling

   * code.
   */

  struct dentry *debugfs_create_blob(const char *name, umode_t mode,

  				   struct dentry *parent,
  				   struct debugfs_blob_wrapper *blob)
  {
  	return debugfs_create_file(name, mode, parent, blob, &fops_blob);
  }
  EXPORT_SYMBOL_GPL(debugfs_create_blob);

  struct array_data {
  	void *array;
  	u32 elements;
  };

  static size_t u32_format_array(char *buf, size_t bufsize,
  			       u32 *array, int array_size)

  {
  	size_t ret = 0;

  	while (--array_size >= 0) {

  		size_t len;

  		char term = array_size ? ' ' : '
  ';

  		len = snprintf(buf, bufsize, "%u%c", *array++, term);

  		ret += len;

  		buf += len;
  		bufsize -= len;

  	}

  	return ret;
  }

  static int u32_array_open(struct inode *inode, struct file *file)

  {

  	struct array_data *data = inode->i_private;

  	int size, elements = data->elements;
  	char *buf;
  
  	/*
  	 * Max size:
  	 *  - 10 digits + ' '/'
  ' = 11 bytes per number
  	 *  - terminating NUL character
  	 */
  	size = elements*11;
  	buf = kmalloc(size+1, GFP_KERNEL);
  	if (!buf)

  		return -ENOMEM;

  	buf[size] = 0;
  
  	file->private_data = buf;
  	u32_format_array(buf, size, data->array, data->elements);

  	return nonseekable_open(inode, file);
  }

  static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
  			      loff_t *ppos)
  {
  	size_t size = strlen(file->private_data);

  
  	return simple_read_from_buffer(buf, len, ppos,
  					file->private_data, size);
  }
  
  static int u32_array_release(struct inode *inode, struct file *file)
  {
  	kfree(file->private_data);
  
  	return 0;
  }
  
  static const struct file_operations u32_array_fops = {
  	.owner	 = THIS_MODULE,
  	.open	 = u32_array_open,
  	.release = u32_array_release,
  	.read	 = u32_array_read,
  	.llseek  = no_llseek,
  };
  
  /**
   * debugfs_create_u32_array - create a debugfs file that is used to read u32
   * array.
   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have.
   * @parent: a pointer to the parent dentry for this file.  This should be a
   *          directory dentry if set.  If this parameter is %NULL, then the
   *          file will be created in the root of the debugfs filesystem.
   * @array: u32 array that provides data.
   * @elements: total number of elements in the array.
   *
   * This function creates a file in debugfs with the given name that exports
   * @array as data. If the @mode variable is so set it can be read from.
   * Writing is not supported. Seek within the file is also not supported.
   * Once array is created its size can not be changed.
   *
   * The function returns a pointer to dentry on success. If debugfs is not
   * enabled in the kernel, the value -%ENODEV will be returned.
   */
  struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
  					    struct dentry *parent,
  					    u32 *array, u32 elements)
  {
  	struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
  
  	if (data == NULL)
  		return NULL;
  
  	data->array = array;
  	data->elements = elements;
  
  	return debugfs_create_file(name, mode, parent, data, &u32_array_fops);
  }
  EXPORT_SYMBOL_GPL(debugfs_create_u32_array);

  #ifdef CONFIG_HAS_IOMEM

  /*
   * The regset32 stuff is used to print 32-bit registers using the
   * seq_file utilities. We offer printing a register set in an already-opened
   * sequential file or create a debugfs file that only prints a regset32.
   */
  
  /**
   * debugfs_print_regs32 - use seq_print to describe a set of registers
   * @s: the seq_file structure being used to generate output
   * @regs: an array if struct debugfs_reg32 structures

   * @nregs: the length of the above array

   * @base: the base address to be used in reading the registers
   * @prefix: a string to be prefixed to every output line
   *
   * This function outputs a text block describing the current values of
   * some 32-bit hardware registers. It is meant to be used within debugfs
   * files based on seq_file that need to show registers, intermixed with other
   * information. The prefix argument may be used to specify a leading string,
   * because some peripherals have several blocks of identical registers,
   * for example configuration of dma channels
   */

  void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
  			  int nregs, void __iomem *base, char *prefix)

  {

  	int i;

  
  	for (i = 0; i < nregs; i++, regs++) {
  		if (prefix)

  			seq_printf(s, "%s", prefix);
  		seq_printf(s, "%s = 0x%08x
  ", regs->name,
  			   readl(base + regs->offset));
  		if (seq_has_overflowed(s))
  			break;

  	}

  }
  EXPORT_SYMBOL_GPL(debugfs_print_regs32);
  
  static int debugfs_show_regset32(struct seq_file *s, void *data)
  {
  	struct debugfs_regset32 *regset = s->private;
  
  	debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
  	return 0;
  }
  
  static int debugfs_open_regset32(struct inode *inode, struct file *file)
  {
  	return single_open(file, debugfs_show_regset32, inode->i_private);
  }
  
  static const struct file_operations fops_regset32 = {
  	.open =		debugfs_open_regset32,
  	.read =		seq_read,
  	.llseek =	seq_lseek,
  	.release =	single_release,
  };
  
  /**
   * debugfs_create_regset32 - create a debugfs file that returns register values
   * @name: a pointer to a string containing the name of the file to create.
   * @mode: the permission that the file should have
   * @parent: a pointer to the parent dentry for this file.  This should be a
   *          directory dentry if set.  If this parameter is %NULL, then the
   *          file will be created in the root of the debugfs filesystem.
   * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
   *          to an array of register definitions, the array size and the base
   *          address where the register bank is to be found.
   *
   * This function creates a file in debugfs with the given name that reports
   * the names and values of a set of 32-bit registers. If the @mode variable
   * is so set it can be read from. Writing is not supported.
   *
   * This function will return a pointer to a dentry if it succeeds.  This
   * pointer must be passed to the debugfs_remove() function when the file is
   * to be removed (no automatic cleanup happens if your module is unloaded,
   * you are responsible here.)  If an error occurs, %NULL will be returned.
   *
   * If debugfs is not enabled in the kernel, the value -%ENODEV will be
   * returned.  It is not wise to check for this value, but rather, check for
   * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
   * code.
   */

  struct dentry *debugfs_create_regset32(const char *name, umode_t mode,

  				       struct dentry *parent,
  				       struct debugfs_regset32 *regset)
  {
  	return debugfs_create_file(name, mode, parent, regset, &fops_regset32);
  }
  EXPORT_SYMBOL_GPL(debugfs_create_regset32);

  
  #endif /* CONFIG_HAS_IOMEM */

  
  struct debugfs_devm_entry {
  	int (*read)(struct seq_file *seq, void *data);
  	struct device *dev;
  };
  
  static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
  {
  	struct debugfs_devm_entry *entry = inode->i_private;
  
  	return single_open(f, entry->read, entry->dev);
  }
  
  static const struct file_operations debugfs_devm_entry_ops = {
  	.owner = THIS_MODULE,
  	.open = debugfs_devm_entry_open,
  	.release = single_release,
  	.read = seq_read,
  	.llseek = seq_lseek
  };
  
  /**
   * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
   *
   * @dev: device related to this debugfs file.
   * @name: name of the debugfs file.
   * @parent: a pointer to the parent dentry for this file.  This should be a
   *	directory dentry if set.  If this parameter is %NULL, then the
   *	file will be created in the root of the debugfs filesystem.
   * @read_fn: function pointer called to print the seq_file content.
   */
  struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name,
  					   struct dentry *parent,
  					   int (*read_fn)(struct seq_file *s,
  							  void *data))
  {
  	struct debugfs_devm_entry *entry;
  
  	if (IS_ERR(parent))
  		return ERR_PTR(-ENOENT);
  
  	entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
  	if (!entry)
  		return ERR_PTR(-ENOMEM);
  
  	entry->read = read_fn;
  	entry->dev = dev;
  
  	return debugfs_create_file(name, S_IRUGO, parent, entry,
  				   &debugfs_devm_entry_ops);
  }
  EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);