[PATCH v24 00/12] Implement PSCI reboot mode driver for PSCI resets

Userspace should be able to initiate device reboots using the various
PSCI SYSTEM_RESET and SYSTEM_RESET2 types defined by PSCI spec. This
patch series introduces psci-reboot-mode driver that will induce
command-based resets to psci driver for executing the device reset.

The PSCI system reset calls takes two arguments: reset_type and cookie.
It defines predefined reset types, such as warm and cold reset, and
vendor-specific reset types which are SoC vendor specific. To support
these requirements, the reboot-mode framework is enhanced in two key
ways:
1. Support upto three 32 bit magic values as arguments. This enables to
support for a 32 bit reset_type and a 64 bit cookie).
2. Predefined modes: Add support for predefined reboot modes in the
framework.

With these enhancements, the patch series enables:
 - Arch Warm reset and system reset cold as predefined reboot modes.
 - Vendor-specific resets, configurable via the SoC-specific device tree.

Together, these changes allow userspace to trigger all above PSCI resets
from userspace.

Note on introducing PSCI-MFD:
In v19/20, psci-reboot-mode was implemented as a faux-device. Review
discussion suggested this may not be the best model for firmware-backed
consumers, and that representing PSCI users as regular platform devices
would be better. One suggestion was to add a PSCI-MFD driver, allowing
multiple consumers tied to a single PSCI node "arm,psci-1.0" be probed
as MFD cells.

Following this, the series adds a PSCI-MFD driver and introduces
cpuidle-psci-domain and psci-reboot-mode as child cells. To meet the
psci-reboot-mode requirement, the MFD core is extended to support
fwnode.
Reference discussions on this:
https://lore.kernel.org/all/[email protected]/

---
The patch is tested on rb3Gen2, lemans-ride, lemans-evk, monaco-ride,
qcs615-ride.

Signed-off-by: Shivendra Pratap <[email protected]>

Changes in v24:
mfd: psci-mfd: Add psci-reboot-mode child cell
 - Remove the explicit check for availability of the reboot-mode node. (by Bart)
 - Fail psci-mfd probe only on fatal errors(-ENOMEM) while adding the
   psci-reboot-mode cell.
mfd: core: Add firmware-node support for MFD cells
 - Allow MFD child registration even when a named child cell not present,
  to align with of_compatible-based registration. (by sashiko)
 - Move named_fwnode logic to a separate function.
power: reset: Add psci-reboot-mode driver
 - Remove dependency on OF. (by Pavan)
 - Update for new changes in predefined modes.
dt-bindings: arm: Document reboot-mode magic
 - Fix the example DT entry. (by Rob)
 - Use unevaluatedProperties as false for the reboot-mode child schema.
firmware: psci: Introduce command-based resets
 - Update in-code documentation. (by Pavan)
 - Update namespace-based exports. (by Pavan)
 - Use synchronized write/read (smp_store_release / smp_load_acquire)for
   the reset command to support lockless atomic reads. (by sashiko)
power: reset: reboot-mode: Add support for predefined reboot modes
 - Remove the predefined list in reboot-mode and add a pointer to
   reboot_mode_entry. (by Pavan)
 - The registering driver fills and manages reboot_mode_entry. (by Pavan)
   - reboot-mode list to append reboot_mode_entry.
power: reset: reboot-mode: Support up to 3 magic values per mode
 - Add separate write function pointers for single-magic writes (existing
   drivers) and multi-value writes. (by Pavan/Bart)
 - Update count to u32. (by Pavan)
power: reset: reboot-mode: Remove devres-based allocations
 - Drop from this series, Sent as separate split-fixes patch.
- Link to v23: https://patch.msgid.link/20260714-arm-psci-system_reset2-vendor-reboots-v23-0-e7453c548c21@oss.qualcomm.com

Changes in v23:
mfd: core: Add firmware-node support to MFD cells
 - Add named_fwnode-based firmware node support in MFD cells.(by Bart)
 - Update the release path. (by Bart)
 - Add checks for duplicate fwnodes.
 - Update documentation for usage and limitations.
mfd: psci-mfd: Add psci-reboot-mode child cell
 - Update for a named_fwnode-based reboot-mode child cell. (By Bart)
 - Split psci-reboot-mode and psci-cpuidle-domain into separate child
   cells.
power: reset: Add psci-reboot-mode driver
 - Add COMPILE_TEST in Kconfig. (by Bart)
 - Update to support up to three u32 arguments to accommodate a
   32-bit reset_type and a 64-bit cookie. (By Sashiko, Lorenzo)
dt-bindings: arm: Document reboot mode magic
 - Update to support up to three u32 arguments to accommodate a
   32-bit reset_type and a 64-bit cookie.
 - Dropped reviewed by from Bart and Rob due to considerable changes.
firmware: psci: Introduce command-based resets
 - Update to support a 64-bit cookie. (By Sashiko, Lorenzo)
 - Update the flow so unsupported reset commands and any failures during
   reset command execution fall back to the
   Linux reboot_mode path. (By Sashiko)
power: reset: reboot-mode: Add support for predefined reboot modes
 - Handle errors and free lists in devm_reboot_mode_register(). (by Sashiko)
 - Update to support up to three u32 arguments.
power: reset: reboot-mode: Support up to 3 magic values per mode
 - Patch for 64 bit magic renamed.
 - Update to support up to three u32 arguments to accommodate a 32-bit
   reset_type and a 64-bit cookie.
 - Dropped reviewed by from Bart and Sebastian due to considerable changes.
- Link to v22: https://lore.kernel.org/r/20260514-arm-psci-system_reset2-vendor-reboots-v22-0-28a5bde07483@oss.qualcomm.com

Changes in v22:
By Bart:
  power: reset: reboot-mode: Add support for predefined reboot modes
  - Add reboot-mode helper to add predefined modes.
  - Add centralized init for reboot-mode.
  - Dropping Reviewed-by from Bartosz as changes may need a review.
  power: reset: Add psci-reboot-mode driver
  - Use reboot-mode helpers to initialize reboot-mode driver and add
    predefined modes.
  mfd: core: Add firmware-node support to MFD cells
  - Use callback function to get fwnode from a MFD child cell.
  mfd: psci-mfd: Add psci-reboot-mode child cell
  - Use callback function to return fwnode for reboot-mode.
By Pankaj:
  mfd: psci-mfd: Add PSCI MFD driver for cpuidle-psci-domain cell
  - Make MFD_PSCI defaults to y as ARM_PSCI_CPUIDLE_DOMAIN defaults to
    y and depends on it.
- Link to v21: https://lore.kernel.org/r/20260427-arm-psci-system_reset2-vendor-reboots-v21-0-dcf937775e73@oss.qualcomm.com

Changes in v21:
By Krzysztof
 power: reset: reboot-mode: Remove devres based allocations
  - remove fixes tag.
By Lorenzo
  firmware: psci: Introduce command-based resets
  - psci_set_reset_cmd() only takes reset_type/cookie as input params.
    - updated this as a encoded u64 reset_command - from Pavan Kondeti.
  - Update commit text for reason for explicit panic_handling.
  - Clean split of reset flow in psci_sys_reset via handle_reboot_mode and handle_cmd_reset.
  - Add psci_has_system_reset2_support() helper and PSCI reset-type defines.
By Lorenzo/Bart
 power: reset: Add psci-reboot-mode driver
  By Bart
   - Drop faux-device based probe.
   - Convert driver to platform-driver model (probed via PSCI MFD).
  By Lorenzo:
   - Use PSCI-specific predefined reset mode naming/magic.
   - Register arch-warm predefined mode only when SYSTEM_RESET2 is supported.
   - psci_reboot_mode_write to directly pass reset_type and cokie.
   - Add MAINTAINERS entry for drivers/power/reset/psci-reboot-mode.c.
By Bart
 mfd: psci-mfd: Introduce psci mfd driver for cpuidle-psci-domain cell
  - Introduce psci-mfd driver.
 mfd: Add psci-reboot-mode cell via fwnode
 - Register psci-reboot-mode from psci-mfd with reboot-mode child node
   fwnode.
 - Update reset Kconfig dependency to tie PSCI reboot-mode to MFD PSCI path.
For alignment:
 - mfd: core: Add firmware-node support to MFD cells
   - Add firmware-node support to MFD cells.
By Pavan
 power: reset: reboot-mode: Add support for predefined reboot modes
  - Move redundant logic of adding modes to list to a common function.
By Arnd
 - Remove refrences for Linux reboot-modes from code and commit text.
By Konrad
 - Updated all dt changes to add reboot-mode for supported board files.
- Link to v20: https://lore.kernel.org/r/20260304-arm-psci-system_reset2-vendor-reboots-v20-0-cf7d346b8372@oss.qualcomm.com

Changes in v20:
By Bart:
 power: reset: Add psci-reboot-mode driver
 - Check for psci compatible in init arm,psci-1.0
 - Node pointer should not be assigned in device probe.
   To Align on above:
   - Remove probe call for faux device.
   - Set node using device_set_node after faux_device_create.
   - Register the reboot mode using explicit call to psci_reboot_mode_register_device.
 - Updated in-code documentation.
For Alignment to use of device_property_xx:
 power: reset: reboot-mode: Add support for 64 bit magic
  - Use device_property_count_u32 instead of device_property_read_u32.
  - Check count of properties before reading.
  - u64 magic changed to u32 magic[2].
  - nvmem-reboot rebased on recent changes.
  - Update documentation and commit text.
power: reset: reboot-mode: Remove devres based allocations
 By Dmitry/Bart:
  - pr_err to pr_debug in case of invalid reboot-mode prop.
 By Bart:
  - Use device_property_read_u32 instead of of_property_read_u32.
  - Avoid repeated code for free list. Now calling unregister from
    error path of regiister_reboot_mode.
 - Fix magic assignment.
- Link to v19: https://lore.kernel.org/r/20251228-arm-psci-system_reset2-vendor-reboots-v19-0-ebb956053098@oss.qualcomm.com

Changes in v19:
- Add missing To/Cc entries (include devicetree list) – Thanks to
  Krzysztof for pointing this out.
- Fix compilation error in reboot-mode.c for ARCH=powerpc by explicitly
  including <linux/slab.h>.
- Link to v18: https://lore.kernel.org/r/20251223-arm-psci-system_reset2-vendor-reboots-v18-0-32fa9e76efc3@oss.qualcomm.com

Changes in v18:
 power: reset: reboot-mode: Remove devres based allocations
 - Update commit text for alignment. – Bart
 - Read magic before assigning kzalloc(info) in reboot_mode_register. - Mukesh
 - Update error handling path. - Mukesh
By Bjorn
 - Expose sysfs for reboot-mode bisected to different series-
   Link: https://lore.kernel.org/all/20251222-next-15nov_expose_sysfs-v21-0-244614135fd8@oss.qualcomm.com/
By Bjorn/Lorenzo/Mukesh
  power: reset: reboot-mode: Add support for 64 bit magic
  - Use FIELD_GET/FIELD_PREP for u64 magic wherever required.
  - Update commit text and add documentation for structure of 64 bit magic.
By Lorenzo
 - Remove direct reboot-mode registration by psci driver.
 - Add support for predefined reboot modes in reboot-mode framework.
 - Add psci-reboot-mode driver and implement a psci-resets to accommodate
   all psci-resets including warm, cold and customizable vendor-resets.
By Bjorn
 - Update DT patches for qcm6490, lemans, monaco and tolos.
  - Update commit text to include more details – By Bjorn
For Alignment
 - dt-bindings: arm: Document reboot mode magic
   - Update reboot mode documentation to clarify that argument1 should provide
     full value of reset_type along with the 31st bit wherever required.
 - DT patches for qcm6490, lemans, monaco and tolos.
   - Provide full value of reset_type including 31st bit.(eg:0x80000001).
- Link to v17: https://lore.kernel.org/r/20251109-arm-psci-system_reset2-vendor-reboots-v17-0-46e085bca4cc@oss.qualcomm.com

Previous versions:
- Link to v16: https://lore.kernel.org/r/20251015-arm-psci-system_reset2-vendor-reboots-v16-0-b98aedaa23ee@oss.qualcomm.com
- Link to v15: https://lore.kernel.org/r/20250922-arm-psci-system_reset2-vendor-reboots-v15-0-7ce3a08878f1@oss.qualcomm.com
- Link to v14: https://lore.kernel.org/r/20250815-arm-psci-system_reset2-vendor-reboots-v14-0-37d29f59ac9a@oss.qualcomm.com
- Link to v13: https://lore.kernel.org/r/20250727-arm-psci-system_reset2-vendor-reboots-v13-0-6b8d23315898@oss.qualcomm.com
- Link to v12: https://lore.kernel.org/r/20250721-arm-psci-system_reset2-vendor-reboots-v12-0-87bac3ec422e@oss.qualcomm.com
- Link to v11: https://lore.kernel.org/r/20250717-arm-psci-system_reset2-vendor-reboots-v11-0-df3e2b2183c3@oss.qualcomm.com
- Link to v10: https://lore.kernel.org/all/[email protected]/
- Link to v9: https://lore.kernel.org/all/20250303-arm-psci-system_reset2-vendor-reboots-v9-0-b2cf4a20feda@oss.qualcomm.com/
- Link to v8: https://lore.kernel.org/r/20241107-arm-psci-system_reset2-vendor-reboots-v8-0-e8715fa65cb5@quicinc.com
- Link to v7: https://lore.kernel.org/r/20241028-arm-psci-system_reset2-vendor-reboots-v7-0-a4c40b0ebc54@quicinc.com
- Link to v6: https://lore.kernel.org/r/20241018-arm-psci-system_reset2-vendor-reboots-v6-0-50cbe88b0a24@quicinc.com
- Link to v5: https://lore.kernel.org/r/20240617-arm-psci-system_reset2-vendor-reboots-v5-0-086950f650c8@quicinc.com
- Link to v4: https://lore.kernel.org/r/20240611-arm-psci-system_reset2-vendor-reboots-v4-0-98f55aa74ae8@quicinc.com
- Link to v3: https://lore.kernel.org/r/20240515-arm-psci-system_reset2-vendor-reboots-v3-0-16dd4f9c0ab4@quicinc.com
- Link to v2: https://lore.kernel.org/r/20240414-arm-psci-system_reset2-vendor-reboots-v2-0-da9a055a648f@quicinc.com
- Link to v1: https://lore.kernel.org/r/20231117-arm-psci-system_reset2-vendor-reboots-v1-0-03c4612153e2@quicinc.com
- Link to RFC: https://lore.kernel.org/r/20231030-arm-psci-system_reset2-vendor-reboots-v1-0-dcdd63352ad1@quicinc.com

To: Lorenzo Pieralisi <[email protected]>
To: Arnd Bergmann <[email protected]>
To: Bartosz Golaszewski <[email protected]>
To: Bjorn Andersson <[email protected]>
To: Sebastian Reichel <[email protected]>
To: Rob Herring <[email protected]>
To: Sudeep Holla <[email protected]>
To: Souvik Chakravarty <[email protected]>
To: Krzysztof Kozlowski <[email protected]>
To: Andy Yan <[email protected]>
To: Matthias Brugger <[email protected]>
To: Mark Rutland <[email protected]>
To: Conor Dooley <[email protected]>
To: Konrad Dybcio <[email protected]>
To: John Stultz <[email protected]>
To: Moritz Fischer <[email protected]>
To: Rafael J. Wysocki <[email protected]>
To: Daniel Lezcano <[email protected]>
To: Christian Loehle <[email protected]>
To: Ulf Hansson <[email protected]>
To: Lee Jones <[email protected]>
To: Ulf Hansson <[email protected]>
To: Pavan Kondeti <[email protected]>
Cc: Florian Fainelli <[email protected]>
Cc: Krzysztof Kozlowski <[email protected]>
Cc: Srinivas Kandagatla <[email protected]>
Cc: Dmitry Baryshkov <[email protected]>
Cc: Mukesh Ojha <[email protected]>
Cc: Andre Draszik <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Kathiravan Thirumoorthy <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]

---
Shivendra Pratap (12):
      power: reset: reboot-mode: Support up to 3 magic values per mode
      power: reset: reboot-mode: Add support for predefined reboot modes
      firmware: psci: Introduce command-based resets
      mfd: psci-mfd: Add PSCI MFD driver for cpuidle-psci-domain cell
      dt-bindings: arm: Document reboot mode magic
      power: reset: Add psci-reboot-mode driver
      mfd: core: Add firmware-node support to MFD cells
      mfd: psci-mfd: Add psci-reboot-mode child cell
      arm64: dts: qcom: Add psci reboot-modes for kodiak boards
      arm64: dts: qcom: Add psci reboot-modes for lemans boards
      arm64: dts: qcom: Add psci reboot-modes for monaco boards
      arm64: dts: qcom: Add psci reboot-modes for talos boards

 Documentation/devicetree/bindings/arm/psci.yaml  |  58 +++++++
 MAINTAINERS                                      |   2 +
 arch/arm64/boot/dts/qcom/kodiak.dtsi             |   2 +-
 arch/arm64/boot/dts/qcom/lemans-evk.dts          |   7 +
 arch/arm64/boot/dts/qcom/lemans-ride-common.dtsi |   7 +
 arch/arm64/boot/dts/qcom/lemans.dtsi             |   2 +-
 arch/arm64/boot/dts/qcom/monaco-evk.dts          |   7 +
 arch/arm64/boot/dts/qcom/monaco.dtsi             |   2 +-
 arch/arm64/boot/dts/qcom/qcm6490-idp.dts         |   7 +
 arch/arm64/boot/dts/qcom/qcs615-ride.dts         |   7 +
 arch/arm64/boot/dts/qcom/qcs6490-rb3gen2.dts     |   7 +
 arch/arm64/boot/dts/qcom/qcs8300-ride.dts        |   7 +
 arch/arm64/boot/dts/qcom/talos.dtsi              |   2 +-
 drivers/cpuidle/Kconfig.arm                      |   1 +
 drivers/cpuidle/cpuidle-psci-domain.c            |   9 +-
 drivers/firmware/psci/psci.c                     | 112 +++++++++++-
 drivers/mfd/Kconfig                              |  12 ++
 drivers/mfd/Makefile                             |   2 +
 drivers/mfd/mfd-core.c                           | 151 +++++++++++++---
 drivers/mfd/psci-mfd.c                           |  68 ++++++++
 drivers/power/reset/Kconfig                      |  10 ++
 drivers/power/reset/Makefile                     |   1 +
 drivers/power/reset/nvmem-reboot-mode.c          |   7 +-
 drivers/power/reset/psci-reboot-mode.c           |  82 +++++++++
 drivers/power/reset/qcom-pon.c                   |   7 +-
 drivers/power/reset/reboot-mode.c                | 208 +++++++++++++++++------
 drivers/power/reset/syscon-reboot-mode.c         |   7 +-
 include/linux/mfd/core.h                         |  10 ++
 include/linux/psci.h                             |  15 ++
 include/linux/reboot-mode.h                      |  27 +++
 30 files changed, 751 insertions(+), 95 deletions(-)
---
base-commit: 415606a7be939835db9b0d6b711887586646346d
change-id: 20250709-arm-psci-system_reset2-vendor-reboots-46c80044afcf

Best regards,
--  
Shivendra Pratap <[email protected]>