Documentation/driver-api/firmware/request_firmware.rst

Source file repositories/reference/linux-study-clean/Documentation/driver-api/firmware/request_firmware.rst

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Linux kernel
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Documentation/driver-api/firmware/request_firmware.rst
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.rst
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Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
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atlas-only

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Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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====================
request_firmware API
====================

You would typically load firmware and then load it into your device somehow.
The typical firmware work flow is reflected below::

	 if(request_firmware(&fw_entry, $FIRMWARE, device) == 0)
                copy_fw_to_device(fw_entry->data, fw_entry->size);
	 release_firmware(fw_entry);

Synchronous firmware requests
=============================

Synchronous firmware requests will wait until the firmware is found or until
an error is returned.

request_firmware
----------------
.. kernel-doc:: drivers/base/firmware_loader/main.c
   :functions: request_firmware

firmware_request_nowarn
-----------------------
.. kernel-doc:: drivers/base/firmware_loader/main.c
   :functions: firmware_request_nowarn

firmware_request_platform
-------------------------
.. kernel-doc:: drivers/base/firmware_loader/main.c
   :functions: firmware_request_platform

request_firmware_direct
-----------------------
.. kernel-doc:: drivers/base/firmware_loader/main.c
   :functions: request_firmware_direct

request_firmware_into_buf
-------------------------
.. kernel-doc:: drivers/base/firmware_loader/main.c
   :functions: request_firmware_into_buf

Asynchronous firmware requests
==============================

Asynchronous firmware requests allow driver code to not have to wait
until the firmware or an error is returned. Function callbacks are
provided so that when the firmware or an error is found the driver is
informed through the callback. request_firmware_nowait() cannot be called
in atomic contexts.

request_firmware_nowait
-----------------------
.. kernel-doc:: drivers/base/firmware_loader/main.c
   :functions: request_firmware_nowait

Special optimizations on reboot
===============================

Some devices have an optimization in place to enable the firmware to be
retained during system reboot. When such optimizations are used the driver
author must ensure the firmware is still available on resume from suspend,
this can be done with firmware_request_cache() instead of requesting for the
firmware to be loaded.

firmware_request_cache()
------------------------
.. kernel-doc:: drivers/base/firmware_loader/main.c
   :functions: firmware_request_cache

Annotation

Implementation Notes