[PATCH v5 0/4] add meson secure watchdog driver

[Xingyu Chen]

The watchdog controller on the Meson-A/C series SoCs is moved to secure world,
We have to call SMC instruction to trap the ATF for watchdog operation. These
operations are different from previous SoCs, so we introduce a new watchdog
driver to support this kind of SoCs.

Changes since v4 at [3]:
- add watchdog node in dts, and introduce a new optional property "timeout-sec"
- add dt-binding for meson secure watchdog
- instantiate wdt device through dts node instead of platform_device_register_simple()

Changes since v3 at [2]:
- add SM_A1_ prefix for WATCHDOG_OPS
- remove phandle to secure-monitor node
- remove watchdog node from dts, and register wdt device by platform_device_register_simple()
- remove dt-binding for meson secure watchdog
- use the msec as unit of timeout parameter which is passed to fw side

Changes since v2 at [1]:
- remove useless dependency in Kconfig
- return zero when getting left time value fails

Changes since v1 at [0]:
- add a new dependency in Kconfig
- simplify/add the return operation
- remove useless ping operation when setting the timeout
- fix some return values
- fix the license statement

[0]:https://lore.kernel.org/linux-amlogic/1570874721-36077-1-git-send-email-xingyu.chen@xxxxxxxxxxx
[1]:https://lore.kernel.org/linux-amlogic/1571387622-35132-1-git-send-email-xingyu.chen@xxxxxxxxxxx
[2]:https://lore.kernel.org/linux-amlogic/1571983984-11771-1-git-send-email-xingyu.chen@xxxxxxxxxxx
[3]:https://lore.kernel.org/linux-amlogic/1574685218-31164-1-git-send-email-xingyu.chen@xxxxxxxxxxx

Xingyu Chen (4):
  firmware: meson_sm: add new SMC ID support for accessing secure
    watchdog
  dt-bindings: watchdog: add new binding for meson secure watchdog
  watchdog: add meson secure watchdog driver
  arm64: dts: a1: add secure watchdog controller

 .../bindings/watchdog/amlogic,meson-sec-wdt.yaml   |  35 ++++
 arch/arm64/boot/dts/amlogic/meson-a1.dtsi          |   6 +
 drivers/firmware/meson/meson_sm.c                  |   1 +
 drivers/watchdog/Kconfig                           |  16 ++
 drivers/watchdog/Makefile                          |   1 +
 drivers/watchdog/meson_sec_wdt.c                   | 188 +++++++++++++++++++++
 include/linux/firmware/meson/meson_sm.h            |   1 +
 7 files changed, 248 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml
 create mode 100644 drivers/watchdog/meson_sec_wdt.c

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2.7.4