[PATCH v6 0/6] Allwinner sun6i message box support

[Samuel Holland]

This series adds support for the "hardware message box" in sun8i, sun9i,
and sun50i SoCs, used for communication with the ARISC management
processor (the platform's equivalent of the ARM SCP). The end goal is to
use the arm_scpi driver as a client, communicating with firmware running
on the ARISC CPU.

I have tested this driver with various firmware programs and mailbox
clients on the A64, H5, and H6 SoCs (including specifically the arm_scpi
driver), and Ondrej Jirman has tested the driver on the A83T (using a
similar patch to arm_scpi).

The clock changes are dropped in favor of:
https://lore.kernel.org/linux-clk/20191230193127.8803-1-samuel@xxxxxxxxxxxx/

Hopefully I've learned my lesson that adding more tangentially-related
patches doesn't increase the likelihood of getting things merged. This
patch just includes the driver and the device tree changes.

Thanks,
Samuel

Changes from v5:
  - Rebased on tag sunxi-dt-for-5.5-2
  - Dropped unnecessary/unrelated patches
  - Addressed Maxime's dt-binding comments
  - Used devm_reset_control_get_exclusive

Changes from v4:
  - Rebased on sunxi-next
  - Dropped AR100 clock patch, as it was controversial and unnecessary
  - Renamed sunxi-msgbox to sun6i-msgbox and sun6i-a31-msgbox
  - Added comments about not asserting the reset line
  - Dropped A80 DTS changes as they were untested
  - Added Ondrej's Tested-by for A83T
  - Dropped the demo; replaced with a real arm_scpi fix

Changes from v3:
  - Rebased on sunxi-next
  - Added Rob's Reviewed-by for patch 3
  - Fixed a crash when receiving a message on a disabled channel
  - Cleaned up some comments/formatting in the driver
  - Fixed #mbox-cells in sunxi-h3-h5.dtsi (patch 7)
  - Removed the irqchip example (no longer relevant to the fw design)
  - Added a demo/example client that uses the driver and a toy firmware

Changes from v2:
  - Merge patches 1-3
  - Add a comment in the code explaining the CLK_IS_CRITICAL usage
  - Add a patch to mark the AR100 clocks as critical
  - Use YAML for the device tree binding
  - Include a not-for-merge example usage of the mailbox

Changes from v1:
  - Marked message box clocks as critical instead of hacks in the driver
  - 8 unidirectional channels instead of 4 bidirectional pairs
  - Use per-SoC compatible strings and an A31 fallback compatible
  - Dropped the mailbox framework patch
  - Include DT patches for SoCs that document the message box

Samuel Holland (6):
  dt-bindings: mailbox: Add a sun6i message box binding
  mailbox: sun6i-msgbox: Add a new mailbox driver
  ARM: dts: sunxi: a83t: Add msgbox node
  ARM: dts: sunxi: h3/h5: Add msgbox node
  arm64: dts: allwinner: a64: Add msgbox node
  arm64: dts: allwinner: h6: Add msgbox node

 .../mailbox/allwinner,sun6i-a31-msgbox.yaml   |  80 +++++
 arch/arm/boot/dts/sun8i-a83t.dtsi             |  10 +
 arch/arm/boot/dts/sunxi-h3-h5.dtsi            |  10 +
 arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi |  10 +
 arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi  |  10 +
 drivers/mailbox/Kconfig                       |   9 +
 drivers/mailbox/Makefile                      |   2 +
 drivers/mailbox/sun6i-msgbox.c                | 332 ++++++++++++++++++
 8 files changed, 463 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/allwinner,sun6i-a31-msgbox.yaml
 create mode 100644 drivers/mailbox/sun6i-msgbox.c

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2.23.0