threeeye
bc1d038eac
Squashed backup commit (no shallow-clone history issues) of xiaomi-mt6833-dev/kernel_xiaomi_mt6833 (lineage-23.2 branch, upstream commit 9eece662e) plus all fixes applied to get everpal_defconfig building clean against a modern (GCC 15.2.0) toolchain -- see the previous commit message on the lineage-23.2 branch (also in this repo history is not available here since this is a squashed snapshot; full incremental history lives in the local DL380 checkout and the upstream GitHub remote). Upstream: https://github.com/xiaomi-mt6833-dev/kernel_xiaomi_mt6833 (lineage-23.2)
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1.6 KiB
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39 lines
1.6 KiB
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=================
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Built-in firmware
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=================
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Firmware can be built-in to the kernel, this means building the firmware
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into vmlinux directly, to enable avoiding having to look for firmware from
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the filesystem. Instead, firmware can be looked for inside the kernel
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directly. You can enable built-in firmware using the kernel configuration
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options:
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* CONFIG_EXTRA_FIRMWARE
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* CONFIG_EXTRA_FIRMWARE_DIR
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This should not be confused with CONFIG_FIRMWARE_IN_KERNEL, this is for drivers
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which enables firmware to be built as part of the kernel build process. This
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option, CONFIG_FIRMWARE_IN_KERNEL, will build all firmware for all drivers
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enabled which ship its firmware inside the Linux kernel source tree.
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There are a few reasons why you might want to consider building your firmware
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into the kernel with CONFIG_EXTRA_FIRMWARE though:
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* Speed
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* Firmware is needed for accessing the boot device, and the user doesn't
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want to stuff the firmware into the boot initramfs.
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Even if you have these needs there are a few reasons why you may not be
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able to make use of built-in firmware:
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* Legalese - firmware is non-GPL compatible
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* Some firmware may be optional
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* Firmware upgrades are possible, therefore a new firmware would implicate
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a complete kernel rebuild.
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* Some firmware files may be really large in size. The remote-proc subsystem
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is an example subsystem which deals with these sorts of firmware
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* The firmware may need to be scraped out from some device specific location
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dynamically, an example is calibration data for for some WiFi chipsets. This
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calibration data can be unique per sold device.
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