Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / base / firmware_class.c
diff --git a/kernel/drivers/base/firmware_class.c b/kernel/drivers/base/firmware_class.c
new file mode 100644 (file)
index 0000000..171841a
--- /dev/null
@@ -0,0 +1,1686 @@
+/*
+ * 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 <linux/security.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_JIFFY_OFFSET;
+}
+
+/* firmware behavior options */
+#define FW_OPT_UEVENT  (1U << 0)
+#define FW_OPT_NOWAIT  (1U << 1)
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+#define FW_OPT_USERHELPER      (1U << 2)
+#else
+#define FW_OPT_USERHELPER      0
+#endif
+#ifdef CONFIG_FW_LOADER_USER_HELPER_FALLBACK
+#define FW_OPT_FALLBACK                FW_OPT_USERHELPER
+#else
+#define FW_OPT_FALLBACK                0
+#endif
+#define FW_OPT_NO_WARN (1U << 3)
+
+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;
+       bool need_uevent;
+       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 void __fw_free_buf(struct kref *ref)
+       __releases(&fwc->lock)
+{
+       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,
+       "/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");
+
+static int fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf)
+{
+       int size;
+       char *buf;
+       int rc;
+
+       if (!S_ISREG(file_inode(file)->i_mode))
+               return -EINVAL;
+       size = i_size_read(file_inode(file));
+       if (size <= 0)
+               return -EINVAL;
+       buf = vmalloc(size);
+       if (!buf)
+               return -ENOMEM;
+       rc = kernel_read(file, 0, buf, size);
+       if (rc != size) {
+               if (rc > 0)
+                       rc = -EIO;
+               goto fail;
+       }
+       rc = security_kernel_fw_from_file(file, buf, size);
+       if (rc)
+               goto fail;
+       fw_buf->data = buf;
+       fw_buf->size = size;
+       return 0;
+fail:
+       vfree(buf);
+       return rc;
+}
+
+static int fw_get_filesystem_firmware(struct device *device,
+                                      struct firmware_buf *buf)
+{
+       int i;
+       int rc = -ENOENT;
+       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;
+               rc = fw_read_file_contents(file, buf);
+               fput(file);
+               if (rc)
+                       dev_warn(device, "firmware, attempted to load %s, but failed with error %d\n",
+                               path, rc);
+               else
+                       break;
+       }
+       __putname(path);
+
+       if (!rc) {
+               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 rc;
+}
+
+/* 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 {
+       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 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 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_RW(timeout),
+       __ATTR_NULL
+};
+
+static void fw_dev_release(struct device *dev)
+{
+       struct firmware_priv *fw_priv = to_firmware_priv(dev);
+
+       kfree(fw_priv);
+}
+
+static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+       struct firmware_priv *fw_priv = to_firmware_priv(dev);
+
+       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 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;
+
+       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;
+       ssize_t written = count;
+       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)) {
+                       int rc;
+
+                       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.
+                        * */
+                       rc = fw_map_pages_buf(fw_buf);
+                       if (rc)
+                               dev_err(dev, "%s: map pages failed\n",
+                                       __func__);
+                       else
+                               rc = security_kernel_fw_from_file(NULL,
+                                               fw_buf->data, fw_buf->size);
+
+                       /*
+                        * Same logic as fw_load_abort, only the DONE bit
+                        * is ignored and we set ABORT only on failure.
+                        */
+                       list_del_init(&fw_buf->pending_list);
+                       if (rc) {
+                               set_bit(FW_STATUS_ABORT, &fw_buf->status);
+                               written = rc;
+                       }
+                       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 written;
+}
+
+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 = PAGE_ALIGN(min_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 struct attribute *fw_dev_attrs[] = {
+       &dev_attr_loading.attr,
+       NULL
+};
+
+static struct bin_attribute *fw_dev_bin_attrs[] = {
+       &firmware_attr_data,
+       NULL
+};
+
+static const struct attribute_group fw_dev_attr_group = {
+       .attrs = fw_dev_attrs,
+       .bin_attrs = fw_dev_bin_attrs,
+};
+
+static const struct attribute_group *fw_dev_attr_groups[] = {
+       &fw_dev_attr_group,
+       NULL
+};
+
+static struct firmware_priv *
+fw_create_instance(struct firmware *firmware, const char *fw_name,
+                  struct device *device, unsigned int opt_flags)
+{
+       struct firmware_priv *fw_priv;
+       struct device *f_dev;
+
+       fw_priv = kzalloc(sizeof(*fw_priv), GFP_KERNEL);
+       if (!fw_priv) {
+               fw_priv = ERR_PTR(-ENOMEM);
+               goto exit;
+       }
+
+       fw_priv->nowait = !!(opt_flags & FW_OPT_NOWAIT);
+       fw_priv->fw = firmware;
+       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;
+       f_dev->groups = fw_dev_attr_groups;
+exit:
+       return fw_priv;
+}
+
+/* load a firmware via user helper */
+static int _request_firmware_load(struct firmware_priv *fw_priv,
+                                 unsigned int opt_flags, 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);
+
+       retval = device_add(f_dev);
+       if (retval) {
+               dev_err(f_dev, "%s: device_register failed\n", __func__);
+               goto err_put_dev;
+       }
+
+       mutex_lock(&fw_lock);
+       list_add(&buf->pending_list, &pending_fw_head);
+       mutex_unlock(&fw_lock);
+
+       if (opt_flags & FW_OPT_UEVENT) {
+               buf->need_uevent = true;
+               dev_set_uevent_suppress(f_dev, false);
+               dev_dbg(f_dev, "firmware: requesting %s\n", buf->fw_id);
+               kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
+       } else {
+               timeout = MAX_JIFFY_OFFSET;
+       }
+
+       retval = wait_for_completion_interruptible_timeout(&buf->completion,
+                       timeout);
+       if (retval == -ERESTARTSYS || !retval) {
+               mutex_lock(&fw_lock);
+               fw_load_abort(fw_priv);
+               mutex_unlock(&fw_lock);
+       } else if (retval > 0) {
+               retval = 0;
+       }
+
+       if (is_fw_load_aborted(buf))
+               retval = -EAGAIN;
+       else if (!buf->data)
+               retval = -ENOMEM;
+
+       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,
+                                   unsigned int opt_flags, long timeout)
+{
+       struct firmware_priv *fw_priv;
+
+       fw_priv = fw_create_instance(firmware, name, device, opt_flags);
+       if (IS_ERR(fw_priv))
+               return PTR_ERR(fw_priv);
+
+       fw_priv->buf = firmware->priv;
+       return _request_firmware_load(fw_priv, opt_flags, timeout);
+}
+
+#ifdef CONFIG_PM_SLEEP
+/* kill pending requests without uevent to avoid blocking suspend */
+static void kill_requests_without_uevent(void)
+{
+       struct firmware_buf *buf;
+       struct firmware_buf *next;
+
+       mutex_lock(&fw_lock);
+       list_for_each_entry_safe(buf, next, &pending_fw_head, pending_list) {
+               if (!buf->need_uevent)
+                        __fw_load_abort(buf);
+       }
+       mutex_unlock(&fw_lock);
+}
+#endif
+
+#else /* CONFIG_FW_LOADER_USER_HELPER */
+static inline int
+fw_load_from_user_helper(struct firmware *firmware, const char *name,
+                        struct device *device, unsigned int opt_flags,
+                        long timeout)
+{
+       return -ENOENT;
+}
+
+/* No abort during direct loading */
+#define is_fw_load_aborted(buf) false
+
+#ifdef CONFIG_PM_SLEEP
+static inline void kill_requests_without_uevent(void) { }
+#endif
+
+#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);
+               ret = wait_for_completion_interruptible(&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,
+                              unsigned int opt_flags)
+{
+       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.
+        */
+       /* don't cache firmware handled without uevent */
+       if (device && (opt_flags & FW_OPT_UEVENT))
+               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, unsigned int opt_flags)
+{
+       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;
+       timeout = firmware_loading_timeout();
+       if (opt_flags & FW_OPT_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_get_filesystem_firmware(device, fw->priv);
+       if (ret) {
+               if (!(opt_flags & FW_OPT_NO_WARN))
+                       dev_warn(device,
+                                "Direct firmware load for %s failed with error %d\n",
+                                name, ret);
+               if (opt_flags & FW_OPT_USERHELPER) {
+                       dev_warn(device, "Falling back to user helper\n");
+                       ret = fw_load_from_user_helper(fw, name, device,
+                                                      opt_flags, timeout);
+               }
+       }
+
+       if (!ret)
+               ret = assign_firmware_buf(fw, device, opt_flags);
+
+       usermodehelper_read_unlock();
+
+ 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)
+{
+       int ret;
+
+       /* Need to pin this module until return */
+       __module_get(THIS_MODULE);
+       ret = _request_firmware(firmware_p, name, device,
+                               FW_OPT_UEVENT | FW_OPT_FALLBACK);
+       module_put(THIS_MODULE);
+       return ret;
+}
+EXPORT_SYMBOL(request_firmware);
+
+/**
+ * request_firmware_direct: - load firmware directly without usermode helper
+ * @firmware_p: pointer to firmware image
+ * @name: name of firmware file
+ * @device: device for which firmware is being loaded
+ *
+ * This function works pretty much like request_firmware(), but this doesn't
+ * fall back to usermode helper even if the firmware couldn't be loaded
+ * directly from fs.  Hence it's useful for loading optional firmwares, which
+ * aren't always present, without extra long timeouts of udev.
+ **/
+int request_firmware_direct(const struct firmware **firmware_p,
+                           const char *name, struct device *device)
+{
+       int ret;
+
+       __module_get(THIS_MODULE);
+       ret = _request_firmware(firmware_p, name, device,
+                               FW_OPT_UEVENT | FW_OPT_NO_WARN);
+       module_put(THIS_MODULE);
+       return ret;
+}
+EXPORT_SYMBOL_GPL(request_firmware_direct);
+
+/**
+ * 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);
+       }
+}
+EXPORT_SYMBOL(release_firmware);
+
+/* 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);
+       unsigned int opt_flags;
+};
+
+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->opt_flags);
+       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->opt_flags = FW_OPT_NOWAIT | FW_OPT_FALLBACK |
+               (uevent ? FW_OPT_UEVENT : FW_OPT_USERHELPER);
+
+       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;
+}
+EXPORT_SYMBOL(request_firmware_nowait);
+
+#ifdef CONFIG_PM_SLEEP
+static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);
+
+/**
+ * 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
+ *
+ */
+static 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;
+}
+
+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;
+}
+
+/**
+ * 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
+ *
+ */
+static 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;
+}
+
+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)
+{
+       queue_delayed_work(system_power_efficient_wq, &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:
+       case PM_RESTORE_PREPARE:
+               kill_requests_without_uevent();
+               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);