firmware_class: Reorganize fw_create_instance()

Recent patches to split up the three phases of request_firmware()
lead to a casting away of const in fw_create_instance(). We can
avoid this cast by splitting up fw_create_instance() a bit.

Make _request_firmware_setup() return a struct fw_priv and use
that struct instead of passing struct firmware to
_request_firmware(). Move the uevent and device file creation
bits to the loading phase and rename the function to
_request_firmware_load() to better reflect its purpose.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
firmware_class: Move request_firmware_nowait() to workqueues

Oddly enough a work_struct was already part of the firmware_work
structure but nobody was using it. Instead of creating a new
kthread for each request_firmware_nowait() call just schedule the
work on the system workqueue. This should avoid some overhead
in forking new threads when they're not strictly necessary.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
firmware loader: simplify pages ownership transfer

This patch doesn't transfer ownership of pages' buffer to the
instance of firmware until the firmware loading is completed,
which will simplify firmware_loading_store a lot, so help
to introduce the following cache_firmware and uncache_firmware
mechanism during system suspend-resume cycle.

In fact, this patch fixes one bug: if writing data into
firmware loader device is bypassed between writting 1 and 0 to
'loading', OOPS will be triggered without the patch.

Also handle the vmap failure case, and add some comments to make
code more readable.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: fix races during loading firmware

This patch fixes two races in loading firmware:

1, FW_STATUS_DONE should be set before waking up the task waitting
on _request_firmware_load, otherwise FW_STATUS_ABORT may be
thought as DONE mistakenly.

2, Inside _request_firmware_load(), there is a small window between
wait_for_completion() and mutex_lock(&fw_lock), and 'echo 1 > loading'
still may happen during the period, so this patch checks FW_STATUS_DONE
to prevent pages' buffer completed from being freed in firmware_loading_store.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: remove unnecessary wmb()

The wmb() inside fw_load_abort is not necessary, since
complete() and wait_on_completion() has implied one pair
of memory barrier.

Also wmb() isn't a correct usage, so just remove it.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: fix creation failure of fw loader device

If one device driver calls request_firmware_nowait() to request
several different firmwares' loading, device_add() will return
failure since all firmware loader device use same name of the
device who is requesting firmware.

This patch always use the name of firmware image as the firmware
loader device name to fix the problem since the following patches
for caching firmware will make sure only one loading for same
firmware is alllowd at the same time.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: introduce firmware_buf

This patch introduces struct firmware_buf to describe the buffer
which holds the firmware data, which will make the following
cache_firmware/uncache_firmware implemented easily.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: always let firmware_buf own the pages buffer

This patch always let firmware_buf own the pages buffer allocated
inside firmware_data_write, and add all instances of firmware_buf
into the firmware cache global list. Also introduce one private field
in 'struct firmware', so release_firmware will see the instance of
firmware_buf associated with the current firmware instance, then just
'free' the instance of firmware_buf.

The firmware_buf instance represents one pages buffer for one
firmware image, so lots of firmware loading requests can share
the same firmware_buf instance if they request the same firmware
image file.

This patch will make implementation of the following cache_firmware/
uncache_firmware very easy and simple.

In fact, the patch improves request_formware/release_firmware:

        - only request userspace to write firmware image once if
	several devices share one same firmware image and its drivers
	call request_firmware concurrently.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: introduce cache_firmware and uncache_firmware

This patches introduce two kernel APIs of cache_firmware and
uncache_firmware, both of which take the firmware file name
as the only parameter.

So any drivers can call cache_firmware to cache the specified
firmware file into kernel memory, and can use the cached firmware
in situations which can't request firmware from user space.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: fix device lifetime

Callers of request_firmware* must hold the reference count of
@device, otherwise it is easy to trigger oops since the firmware
loader device is the child of @device.

This patch adds comments about the usage. In fact, most of drivers
call request_firmware* in its probe() or open(), so the constraint
should be reasonable and can be satisfied.

Also this patch holds the reference count of @device before
schedule_work() in request_firmware_nowait() to avoid that
the @device is released after request_firmware_nowait returns
and before the worker function is scheduled.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: fix comments on request_firmware_nowait

request_firmware_nowait is allowed to be called in atomic
context now if @gfp is GFP_ATOMIC, so fix the obsolete
comments and states which situations are suitable for using
it.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: store firmware name into devres list

This patch will store firmware name into devres list of the device
which is requesting firmware loading, so that we can implement
auto cache and uncache firmware for devices in need.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: introduce device_cache/uncache_fw_images

This patch introduces the three helpers below:

	void device_cache_fw_images(void)
	void device_uncache_fw_images(void)
	void device_uncache_fw_images_delay(unsigned long)

so we can use device_cache_fw_images() to cache firmware for
all devices which need firmware to work, and the device driver
can get the firmware easily from kernel memory when system isn't
ready for completing requests of loading firmware.

After system is ready for completing firmware loading, driver core
will call device_uncache_fw_images() or its delay version to free
the cached firmware.

The above helpers will be used to cache device firmware during
system suspend/resume cycle in the following patches.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: use small timeout for cache device firmware

Because device_cache_fw_images only cache the firmware which has been
loaded sucessfully at leat once, using a small loading timeout should
be reasonable.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: cache devices firmware during suspend/resume cycle

This patch implements caching devices' firmware automatically
during system syspend/resume cycle, so any device drivers can
call request_firmware or request_firmware_nowait inside resume
path to get the cached firmware if they have loaded firmwares
successfully at least once before entering suspend.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: fix compile failure if !PM

'return 0' should be added to fw_pm_notify if !PM because
return value of the funcion is defined as 'int'.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: fix build failure if FW_LOADER is m

device_cache_fw_images need to iterate devices in system,
so this patch applies the introduced dpm_for_each_dev to
avoid link failure if CONFIG_FW_LOADER is m.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: fix firmware -ENOENT situations

If the requested firmware image doesn't exist, firmware->priv
should be set for the later concurrent requests, otherwise
warning and oops will be triggered inside firmware_free_data().

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: let caching firmware piggyback on loading firmware

After starting caching firmware, there is still some time left
before devices are suspended, during the period, request_firmware
or its nowait version may still be triggered by the below situations
to load firmware images which can't be cached during suspend/resume
cycle.

	- new devices added
	- driver bind
	- or device open kind of things

This patch utilizes the piggyback trick to cache firmware for
this kind of situation: just increase the firmware buf's reference
count and add the fw name entry into cache entry list after starting
caching firmware and before syscore_suspend() is called.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware loader: fix compile warning when CONFIG_PM=n

This patch replaces the previous macro of CONFIG_PM with
CONFIG_PM_SLEEP becasue firmware cache is only used in
system sleep situations.

Also this patch fixes the below compile warning when
CONFIG_PM=n:

	drivers/base/firmware_class.c:1147: warning: 'device_cache_fw_images'
	defined but not used
	drivers/base/firmware_class.c:1212: warning:
	'device_uncache_fw_images_delay' defined but not used

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>