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559e947306
The recent ACPI specification extensions have formally defined a method for describing device information with a key=value format that is modeled after the Devicetree/DTS format using a special crafted object named _DSD with a specific UUID for this format. There are three defined Device Property types: Integers, Strings, and References. It is also possible to have arrays of these properties under one key=value pair. Strings and References are both represented as character arrays but result in different generated ACPI OpCodes. Various helpers are provided for writing the Device Property header (to fill in the object name and UUID) and footer (to fill in the property count and device length values) as well as for writing the different Device Property types. A specific helper is provided for writing the defined GPIO binding Device Property that is used to allow GPIOs to be referred to by name rather than resource index. This is all documented in the _DSD Device Properties UUID document: http://uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf This will be used by device drivers to provide device properties that are consumed by the operating system. Devicetree bindings are often described in the linux kernel at Documentation/devicetree/bindings/ A sample driver here has an input GPIO that it needs to describe to the kernel driver: chip.h: struct drivers_generic_sample_config { struct acpi_gpio mode_gpio; }; sample.c: static void acpi_fill_ssdt_generator(struct device *dev) { struct drivers_generic_sample_config *config = dev->chip_info; const char *path = acpi_device_path(dev); ... acpi_device_write_gpio(&config->mode_gpio); ... acpi_dp_write_header(); acpi_dp_write_gpio("mode-gpio", path, 0, 0, 0); acpi_dp_write_footer(); ... } devicetree.cb: device pci 1f.0 on chip drivers/generic/sample register "mode_gpio" = "ACPI_GPIO_INPUT(GPP_B1)" device generic 0 on end end end SSDT.dsl: Name (_CRS, ResourceTemplate () { GpioIo (Exclusive, PullDefault, 0, 0, IoRestrictionInputOnly, "\\_SB.PCI0.GPIO", 0, ResourceConsumer) { 25 } }) Name (_DSD, Package () { ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package () {"mode-gpio", Package () { \_SB.PCI0.LPCB, 0, 0, 1 }} } }) Change-Id: I93ffd09e59d05c09e38693e221a87085469be3ad Signed-off-by: Duncan Laurie <dlaurie@chromium.org> Reviewed-on: https://review.coreboot.org/14937 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@chromium.org> |
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3rdparty | ||
Documentation | ||
payloads | ||
src | ||
util | ||
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.gitmodules | ||
.gitreview | ||
COPYING | ||
MAINTAINERS | ||
Makefile | ||
Makefile.inc | ||
README | ||
toolchain.inc |
------------------------------------------------------------------------------- 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 ------------------ * make * gcc / g++ Because Linux distribution compilers tend to use lots of patches. coreboot does lots of "unusual" things in its build system, some of which break due to those patches, sometimes by gcc aborting, sometimes - and that's worse - by generating broken object code. Two options: use our toolchain (eg. make crosstools-i386) or enable the ANY_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this case). * iasl (for targets with ACPI support) Optional: * doxygen (for generating/viewing documentation) * gdb (for better debugging facilities on some targets) * ncurses (for 'make menuconfig' and 'make nconfig') * 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.