summaryrefslogtreecommitdiffstats
path: root/Documentation/driver-api/firmware/built-in-fw.rst
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /Documentation/driver-api/firmware/built-in-fw.rst
parentInitial commit. (diff)
downloadlinux-upstream.tar.xz
linux-upstream.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--Documentation/driver-api/firmware/built-in-fw.rst33
1 files changed, 33 insertions, 0 deletions
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.
+