[v2,0/5] Expose RPi4's bootloader configuration

Message

Nicolas Saenz Julienne Dec. 18, 2020, 3:43 p.m. UTC

Soon to be released versions of RPi4's firmware will take of care
passing their bootloader's configuration[1] to the OS by copying it into
memory and creating a reserved memory node in the board's DT. By
modeling this reserved memory node as an nvmem device using
'nvmem-rmem', which this series introduces, user-space applications will
be able to query this information through nvmem's sysfs interface.

An alternative approach, less nice IMO, would be to create a
platform-specific 'soc' driver.

Regards,
Nicolas

[1] https://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm2711_bootloader_config.md

---

Changes since v1:
 - Avoid the reserved-memory indirection by integrating the nvmem driver
   into the reserved memory node.

Nicolas Saenz Julienne (5):
  dt-bindings: nvmem: Add bindings for rmem driver
  nvmem: Add driver to expose reserved memory as nvmem
  ARM: dts: bcm2711: Add reserved memory template to hold firmware
    configuration
  arm64: defconfig: Enable nvmem's rmem driver
  ARM: multi_v7_defconfig: Enable nvmem's rmem driver

 .../devicetree/bindings/nvmem/rmem.yaml       | 49 ++++++++++
 arch/arm/boot/dts/bcm2711-rpi-4-b.dts         | 17 ++++
 arch/arm/configs/multi_v7_defconfig           |  1 +
 arch/arm64/configs/defconfig                  |  1 +
 drivers/nvmem/Kconfig                         |  8 ++
 drivers/nvmem/Makefile                        |  2 +
 drivers/nvmem/rmem.c                          | 97 +++++++++++++++++++
 drivers/of/platform.c                         |  1 +
 8 files changed, 176 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/nvmem/rmem.yaml
 create mode 100644 drivers/nvmem/rmem.c