No description
cfb6ea7e65
Add definitions to describe GPIOs in generated ACPI objects and a
method to write a GpioIo() or GpioInt() descriptor to the SSDT.
ACPI GPIOs have many possible configuration options and a structure
is created to describe it accurately in ACPI terms. There are many
shared descriptor fields between GpioIo() and GpioInt() so the same
function can write both types.
GpioInt shares many properties with ACPI Interrupts and the same types
are re-used here where possible. One addition is that GpioInt can be
configured to trigger on both low and high edge transitions.
One descriptor can describe multiple GPIO pins (limited to 8 in this
implementation) that all share configuration and controller and are
used by the same device scope.
Accurately referring to the GPIO controller that this pin is connected
to requires the SoC/board to implement a function handler for
acpi_gpio_path(), or for the caller to provide this directly as a
string in the acpi_gpio->reference variable.
This will get used by device drivers to describe their resources in
the SSDT. Here is a sample for a Maxim 98357A I2S codec which has a
GPIO for power and channel selection called "sdmode".
chip.h:
struct drivers_generic_max98357a_config {
struct acpi_gpio sdmode_gpio;
};
max98357a.c:
void acpi_fill_ssdt_generator(struct device *dev) {
struct drivers_generic_max98357a_config *config = dev->chip_info;
...
acpi_device_write_gpio(&config->sdmode_gpio);
...
}
devicetree.cb:
device pci 1f.3 on
chip drivers/generic/max98357a
register "sdmode_gpio" = "ACPI_GPIO_OUTPUT(GPP_C5)"
device generic 0 on end
end
end
SSDT.dsl:
GpioIo (Exclusive, PullDefault, 0, 0, IoRestrictionOutputOnly,
"\\_SB.PCI0.GPIO", 0, ResourceConsumer, ,) { 53 }
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Change-Id: Ibf5bab9c4bf6f21252373fb013e78f872550b167
Reviewed-on: https://review.coreboot.org/14934
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
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| 3rdparty | ||
| Documentation | ||
| payloads | ||
| src | ||
| util | ||
| .clang-format | ||
| .gitignore | ||
| .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.