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diff --git a/doc/chromium/overview.rst b/doc/chromium/overview.rst new file mode 100644 index 0000000..5498ed9 --- /dev/null +++ b/doc/chromium/overview.rst @@ -0,0 +1,74 @@ +.. SPDX-License-Identifier: GPL-2.0+ +.. Copyright 2020 Google LLC + +Chromium OS Support in U-Boot +============================= + +Introduction +------------ + +This describes how to use U-Boot with Chromium OS. Several options are +available: + + - Running U-Boot from the 'altfw' feature, which is available on selected + Chromebooks from 2019 onwards (initially Grunt). Press '1' from the + developer-mode screen to get into U-Boot. See here for details: + https://chromium.googlesource.com/chromiumos/docs/+/HEAD/developer_mode.md + + - Running U-Boot from the disk partition. This involves signing U-Boot and + placing it on the disk, for booting as a 'kernel'. See + :doc:`chainload` for information on this. This is the only + option on non-U-Boot Chromebooks from 2013 to 2018 and is somewhat + more involved. + + - Running U-Boot with Chromium OS verified boot. This allows U-Boot to be + used instead of either or both of depthcharge (a bootloader which forked + from U-Boot in 2013) and coreboot. See :doc:`run_vboot` for more + information on this. + + - Running U-Boot from coreboot. This allows U-Boot to run on more devices + since many of them only support coreboot as the bootloader and have + no bare-metal support in U-Boot. For this, use the 'coreboot' target. + + - Running U-Boot and booting into a Chrome OS image, but without verified + boot. This can be useful for testing. + + +Talks and documents +------------------- + +Here is some material relevant to Chromium OS verified boot with U-Boot: + + - "U-Boot with Chrome OS and firmware packaging" + + - Author: Simon Glass + - Presented at Open Source Firmware Conference 2018, Erlangen + - Describes the work in progress as at the end of 2018 + - Slides at `OSFC <https://2018.osfc.io/uploads/talk/paper/26/U-Boot_with_Chrome_OS_and_firmware_packaging.pdf>`_ + - Video on `Youtube <https://www.youtube.com/watch?v=1jknxUvmwpo>`_ + + - "Verified Boot in Chrome OS and how to make it work for you" + + - Author: Simon Glass + - Presented at ELCE 2013, Edinburgh + - Describes the original 2013 implementation as shipped on snow (first + `ARM Chromebook was a Samsung Chromebook <https://www.cnet.com/products/samsung-series-3-chromebook-xe303c12-11-6-exynos-5250-2-gb-ram-16-gb-ssd-bilingual-english-french/>`_ + with Samsung Exynos5250 `review <https://www.cnet.com/reviews/samsung-chromebook-series-3-review/>`_), + spring (`HP Chromebook 11 <https://www.cnet.com/products/hp-chromebook-11-g2-11-6-exynos-5250-4-gb-ram-16-gb-emmc/>`_) + and pit/pi (`Samsung Chromebook 2 <https://www.cnet.com/products/samsung-chromebook-2-xe503c12-11-6-exynos-5-octa-4-gb-ram-16-gb-ssd/>`_ + with Exynos 5 Octa 5420 in 2014). + - Slides at `Google research <https://research.google/pubs/pub42038/>`_ + - Video at `Youtube <https://www.youtube.com/watch?v=kdpZC9jFzZA>`_ + + - "Chrome University 2018: Chrome OS Firmware and Verified Boot 201" + + - Author: Duncan Laurie + - Describes Chrome OS firmware as of 2018 and includes a wide range of + topics. This has no U-Boot information, but does cover coreboot and also + talks about the Chrome OS EC and Security chip. This is probably the + best introduction talk. + - Video at `YouTube <https://www.youtube.com/watch?v=WY2sWpuda2g>`_ + + - `Chromium OS U-Boot <https://www.chromium.org/developers/u-boot>`_ + + - `Firmware porting Guide <https://www.chromium.org/chromium-os/firmware-porting-guide>`_ |