| 1 | ====================
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| 2 | request_firmware API
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| 3 | ====================
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| 4 |
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| 5 | You would typically load firmware and then load it into your device somehow.
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| 6 | The typical firmware work flow is reflected below::
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| 7 |
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| 8 | if(request_firmware(&fw_entry, $FIRMWARE, device) == 0)
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| 9 | copy_fw_to_device(fw_entry->data, fw_entry->size);
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| 10 | release_firmware(fw_entry);
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| 11 |
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| 12 | Synchronous firmware requests
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| 13 | =============================
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| 14 |
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| 15 | Synchronous firmware requests will wait until the firmware is found or until
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| 16 | an error is returned.
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| 17 |
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| 18 | request_firmware
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| 19 | ----------------
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| 20 | .. kernel-doc:: drivers/base/firmware_loader/main.c
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| 21 | :functions: request_firmware
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| 22 |
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| 23 | firmware_request_nowarn
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| 24 | -----------------------
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| 25 | .. kernel-doc:: drivers/base/firmware_loader/main.c
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| 26 | :functions: firmware_request_nowarn
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| 27 |
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| 28 | firmware_request_platform
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| 29 | -------------------------
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| 30 | .. kernel-doc:: drivers/base/firmware_loader/main.c
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| 31 | :functions: firmware_request_platform
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| 32 |
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| 33 | request_firmware_direct
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| 34 | -----------------------
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| 35 | .. kernel-doc:: drivers/base/firmware_loader/main.c
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| 36 | :functions: request_firmware_direct
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| 37 |
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| 38 | request_firmware_into_buf
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| 39 | -------------------------
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| 40 | .. kernel-doc:: drivers/base/firmware_loader/main.c
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| 41 | :functions: request_firmware_into_buf
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| 42 |
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| 43 | Asynchronous firmware requests
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| 44 | ==============================
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| 45 |
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| 46 | Asynchronous firmware requests allow driver code to not have to wait
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| 47 | until the firmware or an error is returned. Function callbacks are
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| 48 | provided so that when the firmware or an error is found the driver is
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| 49 | informed through the callback. request_firmware_nowait() cannot be called
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| 50 | in atomic contexts.
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| 51 |
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| 52 | request_firmware_nowait
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| 53 | -----------------------
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| 54 | .. kernel-doc:: drivers/base/firmware_loader/main.c
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| 55 | :functions: request_firmware_nowait
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| 56 |
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| 57 | Special optimizations on reboot
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| 58 | ===============================
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| 59 |
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| 60 | Some devices have an optimization in place to enable the firmware to be
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| 61 | retained during system reboot. When such optimizations are used the driver
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| 62 | author must ensure the firmware is still available on resume from suspend,
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| 63 | this can be done with firmware_request_cache() instead of requesting for the
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| 64 | firmware to be loaded.
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| 65 |
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| 66 | firmware_request_cache()
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| 67 | ------------------------
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| 68 | .. kernel-doc:: drivers/base/firmware_loader/main.c
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| 69 | :functions: firmware_request_cache
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| 70 |
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| 71 | request firmware API expected driver use
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| 72 | ========================================
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| 73 |
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| 74 | Once an API call returns you process the firmware and then release the
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| 75 | firmware. For example if you used request_firmware() and it returns,
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| 76 | the driver has the firmware image accessible in fw_entry->{data,size}.
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| 77 | If something went wrong request_firmware() returns non-zero and fw_entry
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| 78 | is set to NULL. Once your driver is done with processing the firmware it
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| 79 | can call release_firmware(fw_entry) to release the firmware image
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| 80 | and any related resource.
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