[v7,0/5] Implement vendor resets for PSCI SYSTEM_RESET2

Message

Elliot Berman Oct. 28, 2024, 6:44 p.m. UTC

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.

Lorenzo and I are also looking for some feedback on whether it is safe
to perform a vendor SYSTEM_RESET2 irrespective of the enum reboot_mode:

https://lore.kernel.org/all/Zw5ffeYW5uRpsaG3@lpieralisi/

Previous discussions around SYSTEM_RESET2:
- https://lore.kernel.org/lkml/[e-mail]/T/
- https://lore.kernel.org/all/[e-mail]/

Signed-off-by: Elliot Berman <[e-mail]>

Changes in v7:
- Code style nits from Stephen
- Dropped unnecessary hunk from the sa8775p-ride patch
- Link to v6: https://lore.kernel.org/r/[e-mail]

Changes in v6:
- Rebase to v6.11 and fix trivial conflicts in qcm6490-idp
- Add sa8775p-ride support (same as qcm6490-idp)
- Link to v5: https://lore.kernel.org/r/[e-mail]

Changes in v5:
- Drop the nested "items" in prep for future dtschema tools
- Link to v4: https://lore.kernel.org/r/[e-mail]

Changes in v4:
- Change mode- properties from uint32-matrix to uint32-array
- Restructure the reset-types node so only the restriction is in the
  if/then schemas and not the entire definition
- Link to v3: https://lore.kernel.org/r/[e-mail]

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/[e-mail]

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/[e-mail]

Changes in v1:
- Reference reboot-mode bindings as suggeted by Rob.
- Link to RFC: https://lore.kernel.org/r/[e-mail]

---
Elliot Berman (5):
      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
      arm64: dts: qcom: Add PSCI SYSTEM_RESET2 types for sa8775p-ride

 Documentation/devicetree/bindings/arm/psci.yaml    |  43 +++++++++
 .../bindings/power/reset/nvmem-reboot-mode.yaml    |   4 +
 .../devicetree/bindings/power/reset/qcom,pon.yaml  |   7 ++
 .../bindings/power/reset/reboot-mode.yaml          |   4 +-
 .../bindings/power/reset/syscon-reboot-mode.yaml   |   4 +
 arch/arm64/boot/dts/qcom/qcm6490-idp.dts           |   7 ++
 arch/arm64/boot/dts/qcom/sa8775p-ride.dtsi         |   7 ++
 arch/arm64/boot/dts/qcom/sa8775p.dtsi              |   2 +-
 arch/arm64/boot/dts/qcom/sc7280.dtsi               |   2 +-
 drivers/firmware/psci/psci.c                       | 104 +++++++++++++++++++++
 10 files changed, 180 insertions(+), 4 deletions(-)
---
base-commit: 98f7e32f20d28ec452afb208f9cffc08448a2652
change-id: 20231016-arm-psci-system_reset2-vendor-reboots-cc3ad456c070

Best regards,