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linux-stable/Documentation/ABI/testing/sysfs-driver-chromeos-acpi

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platform/chrome: Add ChromeOS ACPI device driver The x86 Chromebooks have the ChromeOS ACPI device. This driver attaches to the ChromeOS ACPI device and exports the values reported by ACPI in a sysfs directory. This data isn't present in ACPI tables when read through ACPI tools, hence a driver is needed to do it. The driver gets data from firmware using the ACPI component of the kernel. The ACPI values are presented in string form (numbers as decimal values) or binary blobs, and can be accessed as the contents of the appropriate read only files in the standard ACPI device's sysfs directory tree. This data is consumed by the ChromeOS user space. Reviewed-by: Guenter Roeck <groeck@chromium.org> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> Co-developed-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org> Link: https://lore.kernel.org/r/Yn4OKYrtV35Dv+nd@debian-BULLSEYE-live-builder-AMD64
2022-05-13 07:52:09 +00:00
What: /sys/bus/platform/devices/GGL0001:*/BINF.2
Date: May 2022
KernelVersion: 5.19
Description:
This file shows information about the current boot of
the active EC firmware.
* 0 - Read only (recovery) firmware.
* 1 - Rewritable firmware.
What: /sys/bus/platform/devices/GGL0001:*/BINF.3
Date: May 2022
KernelVersion: 5.19
Description:
This file shows information about the current boot of
the active main firmware type.
* 0 - Recovery.
* 1 - Normal.
* 2 - Developer.
* 3 - Netboot (factory installation only).
What: /sys/bus/platform/devices/GGL0001:*/CHSW
Date: May 2022
KernelVersion: 5.19
Description:
This file shows the switch position for the Chrome OS specific
hardware switches.
* 0 - No changes.
* 2 - Recovery button was pressed when firmware booted.
* 4 - Recovery button was pressed when EC firmware booted.
* 32 - Developer switch was enabled when firmware booted.
* 512 - Firmware write protection was disabled when firmware
booted.
What: /sys/bus/platform/devices/GGL0001:*/FMAP
Date: May 2022
KernelVersion: 5.19
Description:
This file shows the physical memory address of the start of
the main processor firmware flashmap.
What: /sys/bus/platform/devices/GGL0001:*/FRID
Date: May 2022
KernelVersion: 5.19
Description:
This file shows the firmware version for the read-only portion
of the main processor firmware.
What: /sys/bus/platform/devices/GGL0001:*/FWID
Date: May 2022
KernelVersion: 5.19
Description:
This file shows the firmware version for the rewritable portion
of the main processor firmware.
What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.0
Date: May 2022
KernelVersion: 5.19
Description:
This file shows the type of the GPIO signal for the Chrome OS
specific GPIO assignments.
* 1 - Recovery button.
* 2 - Developer mode switch.
* 3 - Firmware write protection switch.
* 256 to 511 - Debug header GPIO 0 to GPIO 255.
What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.1
Date: May 2022
KernelVersion: 5.19
Description:
This file shows the signal attributes of the GPIO signal.
* 0 - Signal is active low.
* 1 - Signal is active high.
What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.2
Date: May 2022
KernelVersion: 5.19
Description:
This file shows the GPIO number on the specified GPIO
controller.
What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.3
Date: May 2022
KernelVersion: 5.19
Description:
This file shows the name of the GPIO controller.
What: /sys/bus/platform/devices/GGL0001:*/HWID
Date: May 2022
KernelVersion: 5.19
Description:
This file shows the hardware ID for the Chromebook.
What: /sys/bus/platform/devices/GGL0001:*/MECK
Date: May 2022
KernelVersion: 5.19
Description:
This binary file returns the SHA-1 or SHA-256 hash that is
read out of the Management Engine extended registers during
boot. The hash is exported vi ACPI so the OS can verify that
the Management Engine firmware has not changed. If Management
Engine is not present, or if the firmware was unable to read the
extended registers, this buffer size can be zero.
What: /sys/bus/platform/devices/GGL0001:*/VBNV.0
Date: May 2022
KernelVersion: 5.19
Description:
This file shows the offset in CMOS bank 0 of the verified boot
non-volatile storage block, counting from the first writable
CMOS byte (that is, 'offset = 0' is the byte following the 14
bytes of clock data).
What: /sys/bus/platform/devices/GGL0001:*/VBNV.1
Date: May 2022
KernelVersion: 5.19
Description:
This file shows the size in bytes of the verified boot
non-volatile storage block.
What: /sys/bus/platform/devices/GGL0001:*/VDAT
Date: May 2022
KernelVersion: 5.19
Description:
This binary file returns the verified boot data block shared
between the firmware verification step and the kernel
verification step.