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Subject[PATCH v2 0/4] Implement vendor resets for PSCI SYSTEM_RESET2
Date
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, but not 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@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 | 38 ++++++++-
.../bindings/power/reset/nvmem-reboot-mode.yaml | 4 +
.../devicetree/bindings/power/reset/qcom,pon.yaml | 4 +
.../bindings/power/reset/reboot-mode.yaml | 12 ++-
.../bindings/power/reset/syscon-reboot-mode.yaml | 4 +
arch/arm64/boot/dts/qcom/qcm6490-idp.dts | 5 ++
drivers/firmware/psci/psci.c | 90 ++++++++++++++++++++++
7 files changed, 153 insertions(+), 4 deletions(-)
---
base-commit: b5d2afe8745bf3eef5a59a13313798d24f2af983
change-id: 20231016-arm-psci-system_reset2-vendor-reboots-cc3ad456c070

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


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