text: /*
   * firmware_class.c - Multi purpose firmware loading support
   *
   * Copyright (c) 2003 Manuel Estrada Sainz
   *
   * Please see Documentation/firmware_class/ for more information.
   *
   */
  
  #include <linux/capability.h>
  #include <linux/device.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/timer.h>
  #include <linux/vmalloc.h>
  #include <linux/interrupt.h>
  #include <linux/bitops.h>
  #include <linux/mutex.h>
  #include <linux/workqueue.h>
  #include <linux/highmem.h>
  #include <linux/firmware.h>
  #include <linux/slab.h>
  #include <linux/sched.h>
  #include <linux/file.h>
  #include <linux/list.h>
  #include <linux/async.h>
  #include <linux/pm.h>
  #include <linux/suspend.h>
  #include <linux/syscore_ops.h>
  #include <linux/reboot.h>
  
  #include <generated/utsrelease.h>
  
  #include "base.h"
  
  MODULE_AUTHOR("Manuel Estrada Sainz");
  MODULE_DESCRIPTION("Multi purpose firmware loading support");
  MODULE_LICENSE("GPL");
  
  /* Builtin firmware support */
  
  #ifdef CONFIG_FW_LOADER
  
  extern struct builtin_fw __start_builtin_fw[];
  extern struct builtin_fw __end_builtin_fw[];
  
  static bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
  {
  	struct builtin_fw *b_fw;
  
  	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
  		if (strcmp(name, b_fw->name) == 0) {
  			fw->size = b_fw->size;
  			fw->data = b_fw->data;
  			return true;
  		}
  	}
  
  	return false;
  }
  
  static bool fw_is_builtin_firmware(const struct firmware *fw)
  {
  	struct builtin_fw *b_fw;
  
  	for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
  		if (fw->data == b_fw->data)
  			return true;
  
  	return false;
  }
  
  #else /* Module case - no builtin firmware support */
  
  static inline bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
  {
  	return false;
  }
  
  static inline bool fw_is_builtin_firmware(const struct firmware *fw)
  {
  	return false;
  }
  #endif
  
  enum {
  	FW_STATUS_LOADING,
  	FW_STATUS_DONE,
  	FW_STATUS_ABORT,
  };
  
  static int loading_timeout = 60;	/* In seconds */
  
  static inline long firmware_loading_timeout(void)
  {
  	return loading_timeout > 0 ? loading_timeout * HZ : MAX_SCHEDULE_TIMEOUT;
  }
  
  struct firmware_cache {
  	/* firmware_buf instance will be added into the below list */
  	spinlock_t lock;
  	struct list_head head;
  	int state;
  
  #ifdef CONFIG_PM_SLEEP
  	/*
  	 * Names of firmware images which have been cached successfully
  	 * will be added into the below list so that device uncache
  	 * helper can trace which firmware images have been cached
  	 * before.
  	 */
  	spinlock_t name_lock;
  	struct list_head fw_names;
  
  	struct delayed_work work;
  
  	struct notifier_block   pm_notify;
  #endif
  };
  
  struct firmware_buf {
  	struct kref ref;
  	struct list_head list;
  	struct completion completion;
  	struct firmware_cache *fwc;
  	unsigned long status;
  	void *data;
  	size_t size;
  #ifdef CONFIG_FW_LOADER_USER_HELPER
  	bool is_paged_buf;
  	struct page **pages;
  	int nr_pages;
  	int page_array_size;
  	struct list_head pending_list;
  #endif
  	char fw_id[];
  };
  
  struct fw_cache_entry {
  	struct list_head list;
  	char name[];
  };
  
  struct fw_name_devm {
  	unsigned long magic;
  	char name[];
  };
  
  #define to_fwbuf(d) container_of(d, struct firmware_buf, ref)
  
  #define	FW_LOADER_NO_CACHE	0
  #define	FW_LOADER_START_CACHE	1
  
  static int fw_cache_piggyback_on_request(const char *name);
  
  /* fw_lock could be moved to 'struct firmware_priv' but since it is just
   * guarding for corner cases a global lock should be OK */
  static DEFINE_MUTEX(fw_lock);
  
  static struct firmware_cache fw_cache;
  
  static struct firmware_buf *__allocate_fw_buf(const char *fw_name,
  					      struct firmware_cache *fwc)
  {
  	struct firmware_buf *buf;
  
  	buf = kzalloc(sizeof(*buf) + strlen(fw_name) + 1 , GFP_ATOMIC);
  
  	if (!buf)
  		return buf;
  
  	kref_init(&buf->ref);
  	strcpy(buf->fw_id, fw_name);
  	buf->fwc = fwc;
  	init_completion(&buf->completion);
  #ifdef CONFIG_FW_LOADER_USER_HELPER
  	INIT_LIST_HEAD(&buf->pending_list);
  #endif
  
  	pr_debug("%s: fw-%s buf=%p\n", __func__, fw_name, buf);
  
  	return buf;
  }
  
  static struct firmware_buf *__fw_lookup_buf(const char *fw_name)
  {
  	struct firmware_buf *tmp;
  	struct firmware_cache *fwc = &fw_cache;
  
  	list_for_each_entry(tmp, &fwc->head, list)
  		if (!strcmp(tmp->fw_id, fw_name))
  			return tmp;
  	return NULL;
  }
  
  static int fw_lookup_and_allocate_buf(const char *fw_name,
  				      struct firmware_cache *fwc,
  				      struct firmware_buf **buf)
  {
  	struct firmware_buf *tmp;
  
  	spin_lock(&fwc->lock);
  	tmp = __fw_lookup_buf(fw_name);
  	if (tmp) {
  		kref_get(&tmp->ref);
  		spin_unlock(&fwc->lock);
  		*buf = tmp;
  		return 1;
  	}
  	tmp = __allocate_fw_buf(fw_name, fwc);
  	if (tmp)
  		list_add(&tmp->list, &fwc->head);
  	spin_unlock(&fwc->lock);
  
  	*buf = tmp;
  
  	return tmp ? 0 : -ENOMEM;
  }
  
  static struct firmware_buf *fw_lookup_buf(const char *fw_name)
  {
  	struct firmware_buf *tmp;
  	struct firmware_cache *fwc = &fw_cache;
  
  	spin_lock(&fwc->lock);
  	tmp = __fw_lookup_buf(fw_name);
  	spin_unlock(&fwc->lock);
  
  	return tmp;
  }
  
  static void __fw_free_buf(struct kref *ref)
  {
  	struct firmware_buf *buf = to_fwbuf(ref);
  	struct firmware_cache *fwc = buf->fwc;
  
  	pr_debug("%s: fw-%s buf=%p data=%p size=%u\n",
  		 __func__, buf->fw_id, buf, buf->data,
  		 (unsigned int)buf->size);
  
  	list_del(&buf->list);
  	spin_unlock(&fwc->lock);
  
  #ifdef CONFIG_FW_LOADER_USER_HELPER
  	if (buf->is_paged_buf) {
  		int i;
  		vunmap(buf->data);
  		for (i = 0; i < buf->nr_pages; i++)
  			__free_page(buf->pages[i]);
  		kfree(buf->pages);
  	} else
  #endif
  		vfree(buf->data);
  	kfree(buf);
  }
  
  static void fw_free_buf(struct firmware_buf *buf)
  {
  	struct firmware_cache *fwc = buf->fwc;
  	spin_lock(&fwc->lock);
  	if (!kref_put(&buf->ref, __fw_free_buf))
  		spin_unlock(&fwc->lock);
  }
  
  /* direct firmware loading support */
  static char fw_path_para[256];
  static const char * const fw_path[] = {
  	fw_path_para,
  	"/system/etc/firmware",
  	"/lib/firmware/updates/" UTS_RELEASE,
  	"/lib/firmware/updates",
  	"/lib/firmware/" UTS_RELEASE,
  	"/lib/firmware"
  };
  
  /*
   * Typical usage is that passing 'firmware_class.path=$CUSTOMIZED_PATH'
   * from kernel command line because firmware_class is generally built in
   * kernel instead of module.
   */
  module_param_string(path, fw_path_para, sizeof(fw_path_para), 0644);
  MODULE_PARM_DESC(path, "customized firmware image search path with a higher priority than default path");
  
  /* Don't inline this: 'struct kstat' is biggish */
  static noinline_for_stack long fw_file_size(struct file *file)
  {
  	struct kstat st;
  	if (vfs_getattr(&file->f_path, &st))
  		return -1;
  	if (!S_ISREG(st.mode))
  		return -1;
  	if (st.size != (long)st.size)
  		return -1;
  	return st.size;
  }
  
  static bool fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf)
  {
  	long size;
  	char *buf;
  
  	size = fw_file_size(file);
  	if (size <= 0)
  		return false;
  	buf = vmalloc(size);
  	if (!buf)
  		return false;
  	if (kernel_read(file, 0, buf, size) != size) {
  		vfree(buf);
  		return false;
  	}
  	fw_buf->data = buf;
  	fw_buf->size = size;
  	return true;
  }
  
  static bool fw_get_filesystem_firmware(struct device *device,
  				       struct firmware_buf *buf)
  {
  	int i;
  	bool success = false;
  	char *path = __getname();
  
  	for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
  		struct file *file;
  
  		/* skip the unset customized path */
  		if (!fw_path[i][0])
  			continue;
  
  		snprintf(path, PATH_MAX, "%s/%s", fw_path[i], buf->fw_id);
  
  		file = filp_open(path, O_RDONLY, 0);
  		if (IS_ERR(file))
  			continue;
  		success = fw_read_file_contents(file, buf);
  		fput(file);
  		if (success)
  			break;
  	}
  	__putname(path);
  
  	if (success) {
  		dev_dbg(device, "firmware: direct-loading firmware %s\n",
  			buf->fw_id);
  		mutex_lock(&fw_lock);
  		set_bit(FW_STATUS_DONE, &buf->status);
  		complete_all(&buf->completion);
  		mutex_unlock(&fw_lock);
  	}
  
  	return success;
  }
  
  /* firmware holds the ownership of pages */
  static void firmware_free_data(const struct firmware *fw)
  {
  	/* Loaded directly? */
  	if (!fw->priv) {
  		vfree(fw->data);
  		return;
  	}
  	fw_free_buf(fw->priv);
  }
  
  /* store the pages buffer info firmware from buf */
  static void fw_set_page_data(struct firmware_buf *buf, struct firmware *fw)
  {
  	fw->priv = buf;
  #ifdef CONFIG_FW_LOADER_USER_HELPER
  	fw->pages = buf->pages;
  #endif
  	fw->size = buf->size;
  	fw->data = buf->data;
  
  	pr_debug("%s: fw-%s buf=%p data=%p size=%u\n",
  		 __func__, buf->fw_id, buf, buf->data,
  		 (unsigned int)buf->size);
  }
  
  #ifdef CONFIG_PM_SLEEP
  static void fw_name_devm_release(struct device *dev, void *res)
  {
  	struct fw_name_devm *fwn = res;
  
  	if (fwn->magic == (unsigned long)&fw_cache)
  		pr_debug("%s: fw_name-%s devm-%p released\n",
  				__func__, fwn->name, res);
  }
  
  static int fw_devm_match(struct device *dev, void *res,
  		void *match_data)
  {
  	struct fw_name_devm *fwn = res;
  
  	return (fwn->magic == (unsigned long)&fw_cache) &&
  		!strcmp(fwn->name, match_data);
  }
  
  static struct fw_name_devm *fw_find_devm_name(struct device *dev,
  		const char *name)
  {
  	struct fw_name_devm *fwn;
  
  	fwn = devres_find(dev, fw_name_devm_release,
  			  fw_devm_match, (void *)name);
  	return fwn;
  }
  
  /* add firmware name into devres list */
  static int fw_add_devm_name(struct device *dev, const char *name)
  {
  	struct fw_name_devm *fwn;
  
  	fwn = fw_find_devm_name(dev, name);
  	if (fwn)
  		return 1;
  
  	fwn = devres_alloc(fw_name_devm_release, sizeof(struct fw_name_devm) +
  			   strlen(name) + 1, GFP_KERNEL);
  	if (!fwn)
  		return -ENOMEM;
  
  	fwn->magic = (unsigned long)&fw_cache;
  	strcpy(fwn->name, name);
  	devres_add(dev, fwn);
  
  	return 0;
  }
  #else
  static int fw_add_devm_name(struct device *dev, const char *name)
  {
  	return 0;
  }
  #endif
  
  
  /*
   * user-mode helper code
   */
  #ifdef CONFIG_FW_LOADER_USER_HELPER
  struct firmware_priv {
  	struct delayed_work timeout_work;
  	bool nowait;
  	struct device dev;
  	struct firmware_buf *buf;
  	struct firmware *fw;
  };
  
  static struct firmware_priv *to_firmware_priv(struct device *dev)
  {
  	return container_of(dev, struct firmware_priv, dev);
  }
  
  static void __fw_load_abort(struct firmware_buf *buf)
  {
  	/*
  	 * There is a small window in which user can write to 'loading'
  	 * between loading done and disappearance of 'loading'
  	 */
  	if (test_bit(FW_STATUS_DONE, &buf->status))
  		return;
  
  	list_del_init(&buf->pending_list);
  	set_bit(FW_STATUS_ABORT, &buf->status);
  	complete_all(&buf->completion);
  }
  
  static void fw_load_abort(struct firmware_priv *fw_priv)
  {
  	struct firmware_buf *buf = fw_priv->buf;
  
  	__fw_load_abort(buf);
  
  	/* avoid user action after loading abort */
  	fw_priv->buf = NULL;
  }
  
  #define is_fw_load_aborted(buf)	\
  	test_bit(FW_STATUS_ABORT, &(buf)->status)
  
  static LIST_HEAD(pending_fw_head);
  
  /* reboot notifier for avoid deadlock with usermode_lock */
  static int fw_shutdown_notify(struct notifier_block *unused1,
  			      unsigned long unused2, void *unused3)
  {
  	mutex_lock(&fw_lock);
  	while (!list_empty(&pending_fw_head))
  		__fw_load_abort(list_first_entry(&pending_fw_head,
  					       struct firmware_buf,
  					       pending_list));
  	mutex_unlock(&fw_lock);
  	return NOTIFY_DONE;
  }
  
  static struct notifier_block fw_shutdown_nb = {
  	.notifier_call = fw_shutdown_notify,
  };
  
  static ssize_t firmware_timeout_show(struct class *class,
  				     struct class_attribute *attr,
  				     char *buf)
  {
  	return sprintf(buf, "%d\n", loading_timeout);
  }
  
  /**
   * firmware_timeout_store - set number of seconds to wait for firmware
   * @class: device class pointer
   * @attr: device attribute pointer
   * @buf: buffer to scan for timeout value
   * @count: number of bytes in @buf
   *
   *	Sets the number of seconds to wait for the firmware.  Once
   *	this expires an error will be returned to the driver and no
   *	firmware will be provided.
   *
   *	Note: zero means 'wait forever'.
   **/
  static ssize_t firmware_timeout_store(struct class *class,
  				      struct class_attribute *attr,
  				      const char *buf, size_t count)
  {
  	loading_timeout = simple_strtol(buf, NULL, 10);
  	if (loading_timeout < 0)
  		loading_timeout = 0;
  
  	return count;
  }
  
  static struct class_attribute firmware_class_attrs[] = {
  	__ATTR(timeout, S_IWUSR | S_IRUGO,
  		firmware_timeout_show, firmware_timeout_store),
  	__ATTR_NULL
  };
  
  static void fw_dev_release(struct device *dev)
  {
  	struct firmware_priv *fw_priv = to_firmware_priv(dev);
  
  	kfree(fw_priv);
  
  	module_put(THIS_MODULE);
  }
  
  static int do_firmware_uevent(struct firmware_priv *fw_priv, struct kobj_uevent_env *env)
  {
  	if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->buf->fw_id))
  		return -ENOMEM;
  	if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
  		return -ENOMEM;
  	if (add_uevent_var(env, "ASYNC=%d", fw_priv->nowait))
  		return -ENOMEM;
  
  	return 0;
  }
  
  static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
  {
  	struct firmware_priv *fw_priv = to_firmware_priv(dev);
  	int err = 0;
  
  	mutex_lock(&fw_lock);
  	if (fw_priv->buf)
  		err = do_firmware_uevent(fw_priv, env);
  	mutex_unlock(&fw_lock);
  	return err;
  }
  
  static struct class firmware_class = {
  	.name		= "firmware",
  	.class_attrs	= firmware_class_attrs,
  	.dev_uevent	= firmware_uevent,
  	.dev_release	= fw_dev_release,
  };
  
  static ssize_t firmware_loading_show(struct device *dev,
  				     struct device_attribute *attr, char *buf)
  {
  	struct firmware_priv *fw_priv = to_firmware_priv(dev);
  	int loading = 0;
  
  	mutex_lock(&fw_lock);
  	if (fw_priv->buf)
  		loading = test_bit(FW_STATUS_LOADING, &fw_priv->buf->status);
  	mutex_unlock(&fw_lock);
  
  	return sprintf(buf, "%d\n", loading);
  }
  
  /* Some architectures don't have PAGE_KERNEL_RO */
  #ifndef PAGE_KERNEL_RO
  #define PAGE_KERNEL_RO PAGE_KERNEL
  #endif
  
  /* one pages buffer should be mapped/unmapped only once */
  static int fw_map_pages_buf(struct firmware_buf *buf)
  {
  	if (!buf->is_paged_buf)
  		return 0;
  
  	if (buf->data)
  		vunmap(buf->data);
  	buf->data = vmap(buf->pages, buf->nr_pages, 0, PAGE_KERNEL_RO);
  	if (!buf->data)
  		return -ENOMEM;
  	return 0;
  }
  
  /**
   * firmware_loading_store - set value in the 'loading' control file
   * @dev: device pointer
   * @attr: device attribute pointer
   * @buf: buffer to scan for loading control value
   * @count: number of bytes in @buf
   *
   *	The relevant values are:
   *
   *	 1: Start a load, discarding any previous partial load.
   *	 0: Conclude the load and hand the data to the driver code.
   *	-1: Conclude the load with an error and discard any written data.
   **/
  static ssize_t firmware_loading_store(struct device *dev,
  				      struct device_attribute *attr,
  				      const char *buf, size_t count)
  {
  	struct firmware_priv *fw_priv = to_firmware_priv(dev);
  	struct firmware_buf *fw_buf;
  	int loading = simple_strtol(buf, NULL, 10);
  	int i;
  
  	mutex_lock(&fw_lock);
  	fw_buf = fw_priv->buf;
  	if (!fw_buf)
  		goto out;
  
  	switch (loading) {
  	case 1:
  		/* discarding any previous partial load */
  		if (!test_bit(FW_STATUS_DONE, &fw_buf->status)) {
  			for (i = 0; i < fw_buf->nr_pages; i++)
  				__free_page(fw_buf->pages[i]);
  			kfree(fw_buf->pages);
  			fw_buf->pages = NULL;
  			fw_buf->page_array_size = 0;
  			fw_buf->nr_pages = 0;
  			set_bit(FW_STATUS_LOADING, &fw_buf->status);
  		}
  		break;
  	case 0:
  		if (test_bit(FW_STATUS_LOADING, &fw_buf->status)) {
  			set_bit(FW_STATUS_DONE, &fw_buf->status);
  			clear_bit(FW_STATUS_LOADING, &fw_buf->status);
  
  			/*
  			 * Several loading requests may be pending on
  			 * one same firmware buf, so let all requests
  			 * see the mapped 'buf->data' once the loading
  			 * is completed.
  			 * */
  			fw_map_pages_buf(fw_buf);
  			list_del_init(&fw_buf->pending_list);
  			complete_all(&fw_buf->completion);
  			break;
  		}
  		/* fallthrough */
  	default:
  		dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
  		/* fallthrough */
  	case -1:
  		fw_load_abort(fw_priv);
  		break;
  	}
  out:
  	mutex_unlock(&fw_lock);
  	return count;
  }
  
  static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
  
  static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
  				  struct bin_attribute *bin_attr,
  				  char *buffer, loff_t offset, size_t count)
  {
  	struct device *dev = kobj_to_dev(kobj);
  	struct firmware_priv *fw_priv = to_firmware_priv(dev);
  	struct firmware_buf *buf;
  	ssize_t ret_count;
  
  	mutex_lock(&fw_lock);
  	buf = fw_priv->buf;
  	if (!buf || test_bit(FW_STATUS_DONE, &buf->status)) {
  		ret_count = -ENODEV;
  		goto out;
  	}
  	if (offset > buf->size) {
  		ret_count = 0;
  		goto out;
  	}
  	if (count > buf->size - offset)
  		count = buf->size - offset;
  
  	ret_count = count;
  
  	while (count) {
  		void *page_data;
  		int page_nr = offset >> PAGE_SHIFT;
  		int page_ofs = offset & (PAGE_SIZE-1);
  		int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
  
  		page_data = kmap(buf->pages[page_nr]);
  
  		memcpy(buffer, page_data + page_ofs, page_cnt);
  
  		kunmap(buf->pages[page_nr]);
  		buffer += page_cnt;
  		offset += page_cnt;
  		count -= page_cnt;
  	}
  out:
  	mutex_unlock(&fw_lock);
  	return ret_count;
  }
  
  static int fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
  {
  	struct firmware_buf *buf = fw_priv->buf;
  	int pages_needed = ALIGN(min_size, PAGE_SIZE) >> PAGE_SHIFT;
  
  	/* If the array of pages is too small, grow it... */
  	if (buf->page_array_size < pages_needed) {
  		int new_array_size = max(pages_needed,
  					 buf->page_array_size * 2);
  		struct page **new_pages;
  
  		new_pages = kmalloc(new_array_size * sizeof(void *),
  				    GFP_KERNEL);
  		if (!new_pages) {
  			fw_load_abort(fw_priv);
  			return -ENOMEM;
  		}
  		memcpy(new_pages, buf->pages,
  		       buf->page_array_size * sizeof(void *));
  		memset(&new_pages[buf->page_array_size], 0, sizeof(void *) *
  		       (new_array_size - buf->page_array_size));
  		kfree(buf->pages);
  		buf->pages = new_pages;
  		buf->page_array_size = new_array_size;
  	}
  
  	while (buf->nr_pages < pages_needed) {
  		buf->pages[buf->nr_pages] =
  			alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
  
  		if (!buf->pages[buf->nr_pages]) {
  			fw_load_abort(fw_priv);
  			return -ENOMEM;
  		}
  		buf->nr_pages++;
  	}
  	return 0;
  }
  
  /**
   * firmware_data_write - write method for firmware
   * @filp: open sysfs file
   * @kobj: kobject for the device
   * @bin_attr: bin_attr structure
   * @buffer: buffer being written
   * @offset: buffer offset for write in total data store area
   * @count: buffer size
   *
   *	Data written to the 'data' attribute will be later handed to
   *	the driver as a firmware image.
   **/
  static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
  				   struct bin_attribute *bin_attr,
  				   char *buffer, loff_t offset, size_t count)
  {
  	struct device *dev = kobj_to_dev(kobj);
  	struct firmware_priv *fw_priv = to_firmware_priv(dev);
  	struct firmware_buf *buf;
  	ssize_t retval;
  
  	if (!capable(CAP_SYS_RAWIO))
  		return -EPERM;
  
  	mutex_lock(&fw_lock);
  	buf = fw_priv->buf;
  	if (!buf || test_bit(FW_STATUS_DONE, &buf->status)) {
  		retval = -ENODEV;
  		goto out;
  	}
  
  	retval = fw_realloc_buffer(fw_priv, offset + count);
  	if (retval)
  		goto out;
  
  	retval = count;
  
  	while (count) {
  		void *page_data;
  		int page_nr = offset >> PAGE_SHIFT;
  		int page_ofs = offset & (PAGE_SIZE - 1);
  		int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
  
  		page_data = kmap(buf->pages[page_nr]);
  
  		memcpy(page_data + page_ofs, buffer, page_cnt);
  
  		kunmap(buf->pages[page_nr]);
  		buffer += page_cnt;
  		offset += page_cnt;
  		count -= page_cnt;
  	}
  
  	buf->size = max_t(size_t, offset, buf->size);
  out:
  	mutex_unlock(&fw_lock);
  	return retval;
  }
  
  static struct bin_attribute firmware_attr_data = {
  	.attr = { .name = "data", .mode = 0644 },
  	.size = 0,
  	.read = firmware_data_read,
  	.write = firmware_data_write,
  };
  
  static void firmware_class_timeout_work(struct work_struct *work)
  {
  	struct firmware_priv *fw_priv = container_of(work,
  			struct firmware_priv, timeout_work.work);
  
  	mutex_lock(&fw_lock);
  	fw_load_abort(fw_priv);
  	mutex_unlock(&fw_lock);
  }
  
  static struct firmware_priv *
  fw_create_instance(struct firmware *firmware, const char *fw_name,
  		   struct device *device, bool uevent, bool nowait)
  {
  	struct firmware_priv *fw_priv;
  	struct device *f_dev;
  
  	fw_priv = kzalloc(sizeof(*fw_priv), GFP_KERNEL);
  	if (!fw_priv) {
  		dev_err(device, "%s: kmalloc failed\n", __func__);
  		fw_priv = ERR_PTR(-ENOMEM);
  		goto exit;
  	}
  
  	fw_priv->nowait = nowait;
  	fw_priv->fw = firmware;
  	INIT_DELAYED_WORK(&fw_priv->timeout_work,
  		firmware_class_timeout_work);
  
  	f_dev = &fw_priv->dev;
  
  	device_initialize(f_dev);
  	dev_set_name(f_dev, "%s", fw_name);
  	f_dev->parent = device;
  	f_dev->class = &firmware_class;
  exit:
  	return fw_priv;
  }
  
  /* load a firmware via user helper */
  static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
  				  long timeout)
  {
  	int retval = 0;
  	struct device *f_dev = &fw_priv->dev;
  	struct firmware_buf *buf = fw_priv->buf;
  
  	/* fall back on userspace loading */
  	buf->is_paged_buf = true;
  
  	dev_set_uevent_suppress(f_dev, true);
  
  	/* Need to pin this module until class device is destroyed */
  	__module_get(THIS_MODULE);
  
  	retval = device_add(f_dev);
  	if (retval) {
  		dev_err(f_dev, "%s: device_register failed\n", __func__);
  		goto err_put_dev;
  	}
  
  	retval = device_create_bin_file(f_dev, &firmware_attr_data);
  	if (retval) {
  		dev_err(f_dev, "%s: sysfs_create_bin_file failed\n", __func__);
  		goto err_del_dev;
  	}
  
  	mutex_lock(&fw_lock);
  	list_add(&buf->pending_list, &pending_fw_head);
  	mutex_unlock(&fw_lock);
  
  	retval = device_create_file(f_dev, &dev_attr_loading);
  	if (retval) {
  		mutex_lock(&fw_lock);
  		list_del_init(&buf->pending_list);
  		mutex_unlock(&fw_lock);
  		dev_err(f_dev, "%s: device_create_file failed\n", __func__);
  		goto err_del_bin_attr;
  	}
  
  	if (uevent) {
  		dev_set_uevent_suppress(f_dev, false);
  		dev_dbg(f_dev, "firmware: requesting %s\n", buf->fw_id);
  		if (timeout != MAX_SCHEDULE_TIMEOUT)
  			schedule_delayed_work(&fw_priv->timeout_work, timeout);
  
  		kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
  	}
  
  	wait_for_completion(&buf->completion);
  
  	cancel_delayed_work_sync(&fw_priv->timeout_work);
  
  	device_remove_file(f_dev, &dev_attr_loading);
  err_del_bin_attr:
  	device_remove_bin_file(f_dev, &firmware_attr_data);
  err_del_dev:
  	device_del(f_dev);
  err_put_dev:
  	put_device(f_dev);
  	return retval;
  }
  
  static int fw_load_from_user_helper(struct firmware *firmware,
  				    const char *name, struct device *device,
  				    bool uevent, bool nowait, long timeout)
  {
  	struct firmware_priv *fw_priv;
  
  	fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);
  	if (IS_ERR(fw_priv))
  		return PTR_ERR(fw_priv);
  
  	fw_priv->buf = firmware->priv;
  	return _request_firmware_load(fw_priv, uevent, timeout);
  }
  #else /* CONFIG_FW_LOADER_USER_HELPER */
  static inline int
  fw_load_from_user_helper(struct firmware *firmware, const char *name,
  			 struct device *device, bool uevent, bool nowait,
  			 long timeout)
  {
  	return -ENOENT;
  }
  
  /* No abort during direct loading */
  #define is_fw_load_aborted(buf) false
  
  #endif /* CONFIG_FW_LOADER_USER_HELPER */
  
  
  /* wait until the shared firmware_buf becomes ready (or error) */
  static int sync_cached_firmware_buf(struct firmware_buf *buf)
  {
  	int ret = 0;
  
  	mutex_lock(&fw_lock);
  	while (!test_bit(FW_STATUS_DONE, &buf->status)) {
  		if (is_fw_load_aborted(buf)) {
  			ret = -ENOENT;
  			break;
  		}
  		mutex_unlock(&fw_lock);
  		wait_for_completion(&buf->completion);
  		mutex_lock(&fw_lock);
  	}
  	mutex_unlock(&fw_lock);
  	return ret;
  }
  
  /* prepare firmware and firmware_buf structs;
   * return 0 if a firmware is already assigned, 1 if need to load one,
   * or a negative error code
   */
  static int
  _request_firmware_prepare(struct firmware **firmware_p, const char *name,
  			  struct device *device)
  {
  	struct firmware *firmware;
  	struct firmware_buf *buf;
  	int ret;
  
  	*firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
  	if (!firmware) {
  		dev_err(device, "%s: kmalloc(struct firmware) failed\n",
  			__func__);
  		return -ENOMEM;
  	}
  
  	if (fw_get_builtin_firmware(firmware, name)) {
  		dev_dbg(device, "firmware: using built-in firmware %s\n", name);
  		return 0; /* assigned */
  	}
  
  	ret = fw_lookup_and_allocate_buf(name, &fw_cache, &buf);
  
  	/*
  	 * bind with 'buf' now to avoid warning in failure path
  	 * of requesting firmware.
  	 */
  	firmware->priv = buf;
  
  	if (ret > 0) {
  		ret = sync_cached_firmware_buf(buf);
  		if (!ret) {
  			fw_set_page_data(buf, firmware);
  			return 0; /* assigned */
  		}
  	}
  
  	if (ret < 0)
  		return ret;
  	return 1; /* need to load */
  }
  
  static int assign_firmware_buf(struct firmware *fw, struct device *device)
  {
  	struct firmware_buf *buf = fw->priv;
  
  	mutex_lock(&fw_lock);
  	if (!buf->size || is_fw_load_aborted(buf)) {
  		mutex_unlock(&fw_lock);
  		return -ENOENT;
  	}
  
  	/*
  	 * add firmware name into devres list so that we can auto cache
  	 * and uncache firmware for device.
  	 *
  	 * device may has been deleted already, but the problem
  	 * should be fixed in devres or driver core.
  	 */
  	if (device)
  		fw_add_devm_name(device, buf->fw_id);
  
  	/*
  	 * After caching firmware image is started, let it piggyback
  	 * on request firmware.
  	 */
  	if (buf->fwc->state == FW_LOADER_START_CACHE) {
  		if (fw_cache_piggyback_on_request(buf->fw_id))
  			kref_get(&buf->ref);
  	}
  
  	/* pass the pages buffer to driver at the last minute */
  	fw_set_page_data(buf, fw);
  	mutex_unlock(&fw_lock);
  	return 0;
  }
  
  /* called from request_firmware() and request_firmware_work_func() */
  static int
  _request_firmware(const struct firmware **firmware_p, const char *name,
  		  struct device *device, bool uevent, bool nowait)
  {
  	struct firmware *fw;
  	long timeout;
  	int ret;
  
  	if (!firmware_p)
  		return -EINVAL;
  
  	if (!name || name[0] == '\0')
  		return -EINVAL;
  
  	ret = _request_firmware_prepare(&fw, name, device);
  	if (ret <= 0) /* error or already assigned */
  		goto out;
  
  	ret = 0;
  	if (!fw_get_filesystem_firmware(device, fw->priv)) {
  		timeout = firmware_loading_timeout();
  		if (nowait) {
  			timeout = usermodehelper_read_lock_wait(timeout);
  			if (!timeout) {
  				dev_dbg(device, "firmware: %s loading timed out\n",
  					name);
  				ret = -EBUSY;
  				goto out;
  			}
  		} else {
  			ret = usermodehelper_read_trylock();
  			if (WARN_ON(ret)) {
  				dev_err(device, "firmware: %s will not be loaded\n",
  					name);
  				goto out;
  			}
  		}
  
  		ret = fw_load_from_user_helper(fw, name, device,
  					       uevent, nowait, timeout);
  
  		usermodehelper_read_unlock();
  	}
  
  	if (!ret)
  		ret = assign_firmware_buf(fw, device);
  
   out:
  	if (ret < 0) {
  		release_firmware(fw);
  		fw = NULL;
  	}
  
  	*firmware_p = fw;
  	return ret;
  }
  
  /**
   * request_firmware: - send firmware request and wait for it
   * @firmware_p: pointer to firmware image
   * @name: name of firmware file
   * @device: device for which firmware is being loaded
   *
   *      @firmware_p will be used to return a firmware image by the name
   *      of @name for device @device.
   *
   *      Should be called from user context where sleeping is allowed.
   *
   *      @name will be used as $FIRMWARE in the uevent environment and
   *      should be distinctive enough not to be confused with any other
   *      firmware image for this or any other device.
   *
   *	Caller must hold the reference count of @device.
   *
   *	The function can be called safely inside device's suspend and
   *	resume callback.
   **/
  int
  request_firmware(const struct firmware **firmware_p, const char *name,
                   struct device *device)
  {
  	return _request_firmware(firmware_p, name, device, true, false);
  }
  
  /**
   * release_firmware: - release the resource associated with a firmware image
   * @fw: firmware resource to release
   **/
  void release_firmware(const struct firmware *fw)
  {
  	if (fw) {
  		if (!fw_is_builtin_firmware(fw))
  			firmware_free_data(fw);
  		kfree(fw);
  	}
  }
  
  /* Async support */
  struct firmware_work {
  	struct work_struct work;
  	struct module *module;
  	const char *name;
  	struct device *device;
  	void *context;
  	void (*cont)(const struct firmware *fw, void *context);
  	bool uevent;
  };
  
  static void request_firmware_work_func(struct work_struct *work)
  {
  	struct firmware_work *fw_work;
  	const struct firmware *fw;
  
  	fw_work = container_of(work, struct firmware_work, work);
  
  	_request_firmware(&fw, fw_work->name, fw_work->device,
  			  fw_work->uevent, true);
  	fw_work->cont(fw, fw_work->context);
  	put_device(fw_work->device); /* taken in request_firmware_nowait() */
  
  	module_put(fw_work->module);
  	kfree(fw_work);
  }
  
  /**
   * request_firmware_nowait - asynchronous version of request_firmware
   * @module: module requesting the firmware
   * @uevent: sends uevent to copy the firmware image if this flag
   *	is non-zero else the firmware copy must be done manually.
   * @name: name of firmware file
   * @device: device for which firmware is being loaded
   * @gfp: allocation flags
   * @context: will be passed over to @cont, and
   *	@fw may be %NULL if firmware request fails.
   * @cont: function will be called asynchronously when the firmware
   *	request is over.
   *
   *	Caller must hold the reference count of @device.
   *
   *	Asynchronous variant of request_firmware() for user contexts:
   *		- sleep for as small periods as possible since it may
   *		increase kernel boot time of built-in device drivers
   *		requesting firmware in their ->probe() methods, if
   *		@gfp is GFP_KERNEL.
   *
   *		- can't sleep at all if @gfp is GFP_ATOMIC.
   **/
  int
  request_firmware_nowait(
  	struct module *module, bool uevent,
  	const char *name, struct device *device, gfp_t gfp, void *context,
  	void (*cont)(const struct firmware *fw, void *context))
  {
  	struct firmware_work *fw_work;
  
  	fw_work = kzalloc(sizeof (struct firmware_work), gfp);
  	if (!fw_work)
  		return -ENOMEM;
  
  	fw_work->module = module;
  	fw_work->name = name;
  	fw_work->device = device;
  	fw_work->context = context;
  	fw_work->cont = cont;
  	fw_work->uevent = uevent;
  
  	if (!try_module_get(module)) {
  		kfree(fw_work);
  		return -EFAULT;
  	}
  
  	get_device(fw_work->device);
  	INIT_WORK(&fw_work->work, request_firmware_work_func);
  	schedule_work(&fw_work->work);
  	return 0;
  }
  
  /**
   * cache_firmware - cache one firmware image in kernel memory space
   * @fw_name: the firmware image name
   *
   * Cache firmware in kernel memory so that drivers can use it when
   * system isn't ready for them to request firmware image from userspace.
   * Once it returns successfully, driver can use request_firmware or its
   * nowait version to get the cached firmware without any interacting
   * with userspace
   *
   * Return 0 if the firmware image has been cached successfully
   * Return !0 otherwise
   *
   */
  int cache_firmware(const char *fw_name)
  {
  	int ret;
  	const struct firmware *fw;
  
  	pr_debug("%s: %s\n", __func__, fw_name);
  
  	ret = request_firmware(&fw, fw_name, NULL);
  	if (!ret)
  		kfree(fw);
  
  	pr_debug("%s: %s ret=%d\n", __func__, fw_name, ret);
  
  	return ret;
  }
  
  /**
   * uncache_firmware - remove one cached firmware image
   * @fw_name: the firmware image name
   *
   * Uncache one firmware image which has been cached successfully
   * before.
   *
   * Return 0 if the firmware cache has been removed successfully
   * Return !0 otherwise
   *
   */
  int uncache_firmware(const char *fw_name)
  {
  	struct firmware_buf *buf;
  	struct firmware fw;
  
  	pr_debug("%s: %s\n", __func__, fw_name);
  
  	if (fw_get_builtin_firmware(&fw, fw_name))
  		return 0;
  
  	buf = fw_lookup_buf(fw_name);
  	if (buf) {
  		fw_free_buf(buf);
  		return 0;
  	}
  
  	return -EINVAL;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);
  
  static struct fw_cache_entry *alloc_fw_cache_entry(const char *name)
  {
  	struct fw_cache_entry *fce;
  
  	fce = kzalloc(sizeof(*fce) + strlen(name) + 1, GFP_ATOMIC);
  	if (!fce)
  		goto exit;
  
  	strcpy(fce->name, name);
  exit:
  	return fce;
  }
  
  static int __fw_entry_found(const char *name)
  {
  	struct firmware_cache *fwc = &fw_cache;
  	struct fw_cache_entry *fce;
  
  	list_for_each_entry(fce, &fwc->fw_names, list) {
  		if (!strcmp(fce->name, name))
  			return 1;
  	}
  	return 0;
  }
  
  static int fw_cache_piggyback_on_request(const char *name)
  {
  	struct firmware_cache *fwc = &fw_cache;
  	struct fw_cache_entry *fce;
  	int ret = 0;
  
  	spin_lock(&fwc->name_lock);
  	if (__fw_entry_found(name))
  		goto found;
  
  	fce = alloc_fw_cache_entry(name);
  	if (fce) {
  		ret = 1;
  		list_add(&fce->list, &fwc->fw_names);
  		pr_debug("%s: fw: %s\n", __func__, name);
  	}
  found:
  	spin_unlock(&fwc->name_lock);
  	return ret;
  }
  
  static void free_fw_cache_entry(struct fw_cache_entry *fce)
  {
  	kfree(fce);
  }
  
  static void __async_dev_cache_fw_image(void *fw_entry,
  				       async_cookie_t cookie)
  {
  	struct fw_cache_entry *fce = fw_entry;
  	struct firmware_cache *fwc = &fw_cache;
  	int ret;
  
  	ret = cache_firmware(fce->name);
  	if (ret) {
  		spin_lock(&fwc->name_lock);
  		list_del(&fce->list);
  		spin_unlock(&fwc->name_lock);
  
  		free_fw_cache_entry(fce);
  	}
  }
  
  /* called with dev->devres_lock held */
  static void dev_create_fw_entry(struct device *dev, void *res,
  				void *data)
  {
  	struct fw_name_devm *fwn = res;
  	const char *fw_name = fwn->name;
  	struct list_head *head = data;
  	struct fw_cache_entry *fce;
  
  	fce = alloc_fw_cache_entry(fw_name);
  	if (fce)
  		list_add(&fce->list, head);
  }
  
  static int devm_name_match(struct device *dev, void *res,
  			   void *match_data)
  {
  	struct fw_name_devm *fwn = res;
  	return (fwn->magic == (unsigned long)match_data);
  }
  
  static void dev_cache_fw_image(struct device *dev, void *data)
  {
  	LIST_HEAD(todo);
  	struct fw_cache_entry *fce;
  	struct fw_cache_entry *fce_next;
  	struct firmware_cache *fwc = &fw_cache;
  
  	devres_for_each_res(dev, fw_name_devm_release,
  			    devm_name_match, &fw_cache,
  			    dev_create_fw_entry, &todo);
  
  	list_for_each_entry_safe(fce, fce_next, &todo, list) {
  		list_del(&fce->list);
  
  		spin_lock(&fwc->name_lock);
  		/* only one cache entry for one firmware */
  		if (!__fw_entry_found(fce->name)) {
  			list_add(&fce->list, &fwc->fw_names);
  		} else {
  			free_fw_cache_entry(fce);
  			fce = NULL;
  		}
  		spin_unlock(&fwc->name_lock);
  
  		if (fce)
  			async_schedule_domain(__async_dev_cache_fw_image,
  					      (void *)fce,
  					      &fw_cache_domain);
  	}
  }
  
  static void __device_uncache_fw_images(void)
  {
  	struct firmware_cache *fwc = &fw_cache;
  	struct fw_cache_entry *fce;
  
  	spin_lock(&fwc->name_lock);
  	while (!list_empty(&fwc->fw_names)) {
  		fce = list_entry(fwc->fw_names.next,
  				struct fw_cache_entry, list);
  		list_del(&fce->list);
  		spin_unlock(&fwc->name_lock);
  
  		uncache_firmware(fce->name);
  		free_fw_cache_entry(fce);
  
  		spin_lock(&fwc->name_lock);
  	}
  	spin_unlock(&fwc->name_lock);
  }
  
  /**
   * device_cache_fw_images - cache devices' firmware
   *
   * If one device called request_firmware or its nowait version
   * successfully before, the firmware names are recored into the
   * device's devres link list, so device_cache_fw_images can call
   * cache_firmware() to cache these firmwares for the device,
   * then the device driver can load its firmwares easily at
   * time when system is not ready to complete loading firmware.
   */
  static void device_cache_fw_images(void)
  {
  	struct firmware_cache *fwc = &fw_cache;
  	int old_timeout;
  	DEFINE_WAIT(wait);
  
  	pr_debug("%s\n", __func__);
  
  	/* cancel uncache work */
  	cancel_delayed_work_sync(&fwc->work);
  
  	/*
  	 * use small loading timeout for caching devices' firmware
  	 * because all these firmware images have been loaded
  	 * successfully at lease once, also system is ready for
  	 * completing firmware loading now. The maximum size of
  	 * firmware in current distributions is about 2M bytes,
  	 * so 10 secs should be enough.
  	 */
  	old_timeout = loading_timeout;
  	loading_timeout = 10;
  
  	mutex_lock(&fw_lock);
  	fwc->state = FW_LOADER_START_CACHE;
  	dpm_for_each_dev(NULL, dev_cache_fw_image);
  	mutex_unlock(&fw_lock);
  
  	/* wait for completion of caching firmware for all devices */
  	async_synchronize_full_domain(&fw_cache_domain);
  
  	loading_timeout = old_timeout;
  }
  
  /**
   * device_uncache_fw_images - uncache devices' firmware
   *
   * uncache all firmwares which have been cached successfully
   * by device_uncache_fw_images earlier
   */
  static void device_uncache_fw_images(void)
  {
  	pr_debug("%s\n", __func__);
  	__device_uncache_fw_images();
  }
  
  static void device_uncache_fw_images_work(struct work_struct *work)
  {
  	device_uncache_fw_images();
  }
  
  /**
   * device_uncache_fw_images_delay - uncache devices firmwares
   * @delay: number of milliseconds to delay uncache device firmwares
   *
   * uncache all devices's firmwares which has been cached successfully
   * by device_cache_fw_images after @delay milliseconds.
   */
  static void device_uncache_fw_images_delay(unsigned long delay)
  {
  	schedule_delayed_work(&fw_cache.work,
  			msecs_to_jiffies(delay));
  }
  
  static int fw_pm_notify(struct notifier_block *notify_block,
  			unsigned long mode, void *unused)
  {
  	switch (mode) {
  	case PM_HIBERNATION_PREPARE:
  	case PM_SUSPEND_PREPARE:
  		device_cache_fw_images();
  		break;
  
  	case PM_POST_SUSPEND:
  	case PM_POST_HIBERNATION:
  	case PM_POST_RESTORE:
  		/*
  		 * In case that system sleep failed and syscore_suspend is
  		 * not called.
  		 */
  		mutex_lock(&fw_lock);
  		fw_cache.state = FW_LOADER_NO_CACHE;
  		mutex_unlock(&fw_lock);
  
  		device_uncache_fw_images_delay(10 * MSEC_PER_SEC);
  		break;
  	}
  
  	return 0;
  }
  
  /* stop caching firmware once syscore_suspend is reached */
  static int fw_suspend(void)
  {
  	fw_cache.state = FW_LOADER_NO_CACHE;
  	return 0;
  }
  
  static struct syscore_ops fw_syscore_ops = {
  	.suspend = fw_suspend,
  };
  #else
  static int fw_cache_piggyback_on_request(const char *name)
  {
  	return 0;
  }
  #endif
  
  static void __init fw_cache_init(void)
  {
  	spin_lock_init(&fw_cache.lock);
  	INIT_LIST_HEAD(&fw_cache.head);
  	fw_cache.state = FW_LOADER_NO_CACHE;
  
  #ifdef CONFIG_PM_SLEEP
  	spin_lock_init(&fw_cache.name_lock);
  	INIT_LIST_HEAD(&fw_cache.fw_names);
  
  	INIT_DELAYED_WORK(&fw_cache.work,
  			  device_uncache_fw_images_work);
  
  	fw_cache.pm_notify.notifier_call = fw_pm_notify;
  	register_pm_notifier(&fw_cache.pm_notify);
  
  	register_syscore_ops(&fw_syscore_ops);
  #endif
  }
  
  static int __init firmware_class_init(void)
  {
  	fw_cache_init();
  #ifdef CONFIG_FW_LOADER_USER_HELPER
  	register_reboot_notifier(&fw_shutdown_nb);
  	return class_register(&firmware_class);
  #else
  	return 0;
  #endif
  }
  
  static void __exit firmware_class_exit(void)
  {
  #ifdef CONFIG_PM_SLEEP
  	unregister_syscore_ops(&fw_syscore_ops);
  	unregister_pm_notifier(&fw_cache.pm_notify);
  #endif
  #ifdef CONFIG_FW_LOADER_USER_HELPER
  	unregister_reboot_notifier(&fw_shutdown_nb);
  	class_unregister(&firmware_class);
  #endif
  }
  
  fs_initcall(firmware_class_init);
  module_exit(firmware_class_exit);
  
  EXPORT_SYMBOL(release_firmware);
  EXPORT_SYMBOL(request_firmware);
  EXPORT_SYMBOL(request_firmware_nowait);
  EXPORT_SYMBOL_GPL(cache_firmware);
  EXPORT_SYMBOL_GPL(uncache_firmware);
  