[PATCH v3 0/4] Implement vendor resets for PSCI SYSTEM_RESET2

[Elliot Berman]

The PSCI SYSTEM_RESET2 call allows vendor firmware to define additional
reset types which could be mapped to the reboot argument.

Setting up reboot on Qualcomm devices can be inconsistent from chipset
to chipset. Generally, there is a PMIC register that gets written to
decide the reboot type. There is also sometimes a cookie that can be
written to indicate that the bootloader should behave differently than a
regular boot. These knobs evolve over product generations and require 
more drivers. Qualcomm firmwares are beginning to expose vendor
SYSTEM_RESET2 types to simplify driver requirements from Linux.

Add support in PSCI to statically wire reboot mode commands from
userspace to a vendor reset and cookie value using the device tree. The
DT bindings are similar to reboot mode framework except that 2
integers are accepted (the type and cookie). Also, reboot mode framework
is intended to program the cookies, but not actually reboot the host.
PSCI SYSTEM_RESET2 does both. I've not added support for reading ACPI
tables since I don't have any device which provides them + firmware that
supports vendor SYSTEM_RESET2 types.

Previous discussions around SYSTEM_RESET2:
- https://lore.kernel.org/lkml/20230724223057.1208122-2-quic_eberman@quicinc.com/T/
- https://lore.kernel.org/all/4a679542-b48d-7e11-f33a-63535a5c68cb@quicinc.com/

Signed-off-by: Elliot Berman <quic_eberman at quicinc.com>
---
Changes in v3:
- Limit outer number of items to 1 for mode-* properties
- Move the reboot-mode for psci under a subnode "reset-types"
- Fix the DT node in qcm6490-idp so it doesn't overwrite the one from
  sc7820.dtsi
- Link to v2: https://lore.kernel.org/r/20240414-arm-psci-system_reset2-vendor-reboots-v2-0-da9a055a648f@quicinc.com

Changes in v2:
- Fixes to schema as suggested by Rob and Krzysztof
- Add qcm6490 idp as first Qualcomm device to support
- Link to v1: https://lore.kernel.org/r/20231117-arm-psci-system_reset2-vendor-reboots-v1-0-03c4612153e2@quicinc.com

Changes in v1:
- Reference reboot-mode bindings as suggeted by Rob.
- Link to RFC: https://lore.kernel.org/r/20231030-arm-psci-system_reset2-vendor-reboots-v1-0-dcdd63352ad1@quicinc.com

---
Elliot Berman (4):
      dt-bindings: power: reset: Convert mode-.* properties to array
      dt-bindings: arm: Document reboot mode magic
      firmware: psci: Read and use vendor reset types
      arm64: dts: qcom: Add PSCI SYSTEM_RESET2 types for qcm6490-idp

 Documentation/devicetree/bindings/arm/psci.yaml    | 43 +++++++++-
 .../bindings/power/reset/nvmem-reboot-mode.yaml    |  4 +
 .../devicetree/bindings/power/reset/qcom,pon.yaml  |  4 +
 .../bindings/power/reset/reboot-mode.yaml          | 14 +++-
 .../bindings/power/reset/syscon-reboot-mode.yaml   |  4 +
 arch/arm64/boot/dts/qcom/qcm6490-idp.dts           |  7 ++
 arch/arm64/boot/dts/qcom/sc7280.dtsi               |  2 +-
 drivers/firmware/psci/psci.c                       | 92 ++++++++++++++++++++++
 8 files changed, 165 insertions(+), 5 deletions(-)
---
base-commit: b5d2afe8745bf3eef5a59a13313798d24f2af983
change-id: 20231016-arm-psci-system_reset2-vendor-reboots-cc3ad456c070

Best regards,
-- 
Elliot Berman <quic_eberman at quicinc.com>