From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- Documentation/driver-api/firmware/built-in-fw.rst | 33 +++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 Documentation/driver-api/firmware/built-in-fw.rst (limited to 'Documentation/driver-api/firmware/built-in-fw.rst') diff --git a/Documentation/driver-api/firmware/built-in-fw.rst b/Documentation/driver-api/firmware/built-in-fw.rst new file mode 100644 index 000000000..bc1c961ba --- /dev/null +++ b/Documentation/driver-api/firmware/built-in-fw.rst @@ -0,0 +1,33 @@ +================= +Built-in firmware +================= + +Firmware can be built-in to the kernel, this means building the firmware +into vmlinux directly, to enable avoiding having to look for firmware from +the filesystem. Instead, firmware can be looked for inside the kernel +directly. You can enable built-in firmware using the kernel configuration +options: + + * CONFIG_EXTRA_FIRMWARE + * CONFIG_EXTRA_FIRMWARE_DIR + +There are a few reasons why you might want to consider building your firmware +into the kernel with CONFIG_EXTRA_FIRMWARE: + +* Speed +* Firmware is needed for accessing the boot device, and the user doesn't + want to stuff the firmware into the boot initramfs. + +Even if you have these needs there are a few reasons why you may not be +able to make use of built-in firmware: + +* Legalese - firmware is non-GPL compatible +* Some firmware may be optional +* Firmware upgrades are possible, therefore a new firmware would implicate + a complete kernel rebuild. +* Some firmware files may be really large in size. The remote-proc subsystem + is an example subsystem which deals with these sorts of firmware +* The firmware may need to be scraped out from some device specific location + dynamically, an example is calibration data for some WiFi chipsets. This + calibration data can be unique per sold device. + -- cgit v1.2.3