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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
- 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
- request firmware API expected driver use
- ========================================
- Once an API call returns you process the firmware and then release the
- firmware. For example if you used request_firmware() and it returns,
- the driver has the firmware image accessible in fw_entry->{data,size}.
- If something went wrong request_firmware() returns non-zero and fw_entry
- is set to NULL. Once your driver is done with processing the firmware it
- can call call release_firmware(fw_entry) to release the firmware image
- and any related resource.
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