[PATCH v3 0/3] coreboot CFR firmware attributes

[Sean Rhodes <sean@starlabs.systems>]

Hi,

This series adds a coreboot CFR firmware-attributes driver.

v3 addresses Julius's review feedback that this does not belong under
platform/x86.  The driver now lives under drivers/firmware/coreboot/,
next to the existing coreboot table consumers.  To support that, the
firmware-attributes class helper is moved from drivers/platform/x86 to
drivers/firmware.

The series also renames drivers/firmware/google to
drivers/firmware/coreboot, because the drivers in that directory are
coreboot table drivers rather than Google-specific firmware drivers.
The existing CONFIG_GOOGLE_* symbols are intentionally kept to avoid
user configuration churn.

The CFR driver uses the existing firmware-attributes ABI.  It exposes
runtime EFI variable-backed boolean, enum and integer options, skips
suppressed, volatile, dependency-gated and non-runtime options, and keeps
read-only or inactive options read-only in sysfs.

For CFR runtime-apply metadata using APM_CNT, x86 systems can apply a
setting immediately after writing the EFI variable.  Non-x86 builds keep
the EFI write and report pending_reboot.

Changes in v3:
- Move the driver from platform/x86 to drivers/firmware/coreboot.
- Split out the firmware-attributes class helper move.
- Rename drivers/firmware/google to drivers/firmware/coreboot.
- Keep CONFIG_GOOGLE_* symbols unchanged.
- Keep coreboot bus internals private to drivers/firmware/coreboot.
- Keep CFR record definitions private to the CFR driver.
- Avoid rewriting EFI variables when userspace writes the current value.

Testing:
- Tested on a Star Labs Byte with firmware 26.07 and the driver built as a
  module against Linux 6.17.
- Verified runtime APM_CNT apply with power_led.
- Verified reboot-needed behavior with debug_level.
- Built x86 objects with W=1 for the CFR/coreboot/helper path and touched
  platform-x86 firmware-attributes users.
- Built ARM64 objects with clang for the CFR/coreboot/helper path.
- Passed git diff --check and scripts/checkpatch.pl --strict.

Sean Rhodes (3):
  firmware: Move firmware attributes class helper
  firmware: Rename google firmware directory to coreboot
  firmware: coreboot: Add CFR firmware attributes driver

 MAINTAINERS                                   |   18 +-
 drivers/firmware/Kconfig                      |    5 +-
 drivers/firmware/Makefile                     |    3 +-
 drivers/firmware/{google => coreboot}/Kconfig |   19 +-
 .../firmware/{google => coreboot}/Makefile    |    1 +
 drivers/firmware/{google => coreboot}/cbmem.c |    0
 drivers/firmware/coreboot/coreboot-cfr.c      | 1068 +++++++++++++++++
 .../{google => coreboot}/coreboot_table.c     |    0
 .../{google => coreboot}/coreboot_table.h     |    0
 .../framebuffer-coreboot.c                    |    0
 drivers/firmware/{google => coreboot}/gsmi.c  |    0
 .../memconsole-coreboot.c                     |    0
 .../memconsole-x86-legacy.c                   |    0
 .../{google => coreboot}/memconsole.c         |    0
 .../{google => coreboot}/memconsole.h         |    6 +-
 drivers/firmware/{google => coreboot}/vpd.c   |    0
 .../{google => coreboot}/vpd_decode.c         |    0
 .../{google => coreboot}/vpd_decode.h         |    0
 .../firmware_attributes_class.c               |    2 +-
 drivers/platform/x86/Kconfig                  |    3 -
 drivers/platform/x86/Makefile                 |    2 -
 drivers/platform/x86/asus-armoury.c           |    2 +-
 .../x86/dell/dell-wmi-sysman/sysman.c         |    2 +-
 drivers/platform/x86/hp/hp-bioscfg/bioscfg.c  |    2 +-
 drivers/platform/x86/lenovo/think-lmi.c       |    2 +-
 drivers/platform/x86/lenovo/wmi-other.c       |    2 +-
 drivers/platform/x86/samsung-galaxybook.c     |    2 +-
 .../linux/firmware_attributes.h               |    6 +-
 28 files changed, 1120 insertions(+), 25 deletions(-)
 rename drivers/firmware/{google => coreboot}/Kconfig (83%)
 rename drivers/firmware/{google => coreboot}/Makefile (92%)
 rename drivers/firmware/{google => coreboot}/cbmem.c (100%)
 create mode 100644 drivers/firmware/coreboot/coreboot-cfr.c
 rename drivers/firmware/{google => coreboot}/coreboot_table.c (100%)
 rename drivers/firmware/{google => coreboot}/coreboot_table.h (100%)
 rename drivers/firmware/{google => coreboot}/framebuffer-coreboot.c (100%)
 rename drivers/firmware/{google => coreboot}/gsmi.c (100%)
 rename drivers/firmware/{google => coreboot}/memconsole-coreboot.c (100%)
 rename drivers/firmware/{google => coreboot}/memconsole-x86-legacy.c (100%)
 rename drivers/firmware/{google => coreboot}/memconsole.c (100%)
 rename drivers/firmware/{google => coreboot}/memconsole.h (82%)
 rename drivers/firmware/{google => coreboot}/vpd.c (100%)
 rename drivers/firmware/{google => coreboot}/vpd_decode.c (100%)
 rename drivers/firmware/{google => coreboot}/vpd_decode.h (100%)
 rename drivers/{platform/x86 => firmware}/firmware_attributes_class.c (94%)
 rename drivers/platform/x86/firmware_attributes_class.h => include/linux/firmware_attributes.h (60%)