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f40a2590ac
The Emerald Lake 2 CRB wasn't designed with ChromeOS in mind, so there aren't any actual developer mode, recovery mode, or write protect switches, let alone GPIOs to read them from. Instead, I've commandeered signals connected to GPIOs which are for other things but which aren't used by hardware or, for instance, the EC to do something Coreboot doesn't control. The recovery mode switch is connected to GPIO 22 and is called BIOS_REC on the schematic. The name is at least very reminiscent of the right thing even if it's supposed to be used for something else. There's a jumper on the board labelled J8G1 which can force the line to ground, and if not, there's a switch on the front of the case which toggles its value. "RECOVER" is for recovery mode and "KEEP" is for normal mode. The developer mode switch is connected to GPIO 57 and is called SV_DET on the schematic. It's connected to a jumper labelled J8E2 on the board and, as far as I can tell, can't be controlled in any other way. When the jumper is in place and the pins are shorted, developer mode is selected. When the jumper is removed, normal mode is selected. The write protect is connected to GPIO 48 which is called BIOS_RESP on the schematic. It's connected to a jumper labelled J8E3 which, like j8E2, seems to be the only way to control the line it's on. When the jumper is in place, write protect is "disabled", and when it's in place it's "enabled" even though there's no functional difference. The input for the recovery mode switch was chosen because of the name it already had on the CRB, BIOS recovery, and because there's a switch to control it on the front of the case which makes it easy to get at. The jumpers for developer mode and recovery mode were chosen because there weren't very many options available, and of those these were next to each other which should make them easier to find and work with. It might be a good idea to wire toggle switches up to the pins of those jumpers so they'll be easy to identify, can be labelled, and would be easier to work with than little jumpers in the middle of the motherboard. Change-Id: Ib2c3dc05077dacfbede596dae143ed81a99dbebd Signed-off-by: Gabe Black <gabeblack@google.com> Reviewed-on: http://review.coreboot.org/965 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com> |
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| README | ||
------------------------------------------------------------------------------- coreboot README ------------------------------------------------------------------------------- coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload. With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required. coreboot was formerly known as LinuxBIOS. Payloads -------- After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot. See http://www.coreboot.org/Payloads for a list of supported payloads. Supported Hardware ------------------ coreboot supports a wide range of chipsets, devices, and mainboards. For details please consult: * http://www.coreboot.org/Supported_Motherboards * http://www.coreboot.org/Supported_Chipsets_and_Devices Build Requirements ------------------ * gcc / g++ * make Optional: * doxygen (for generating/viewing documentation) * iasl (for targets with ACPI support) * gdb (for better debugging facilities on some targets) * ncurses (for 'make menuconfig') * flex and bison (for regenerating parsers) Building coreboot ----------------- Please consult http://www.coreboot.org/Build_HOWTO for details. Testing coreboot Without Modifying Your Hardware ------------------------------------------------ If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU. Please see http://www.coreboot.org/QEMU for details. Website and Mailing List ------------------------ Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website: http://www.coreboot.org You can contact us directly on the coreboot mailing list: http://www.coreboot.org/Mailinglist Copyright and License --------------------- The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details. coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details. This makes the resulting coreboot images licensed under the GPL, version 2.