i.MX8QXP is an ARMv8 Cortex-A35 SoC with a Cortex-M4 system controller inside, the system controller manages overall power, clock, secure RTC and watchdog etc., so Linux kernel running on A35 needs to communicate with system controller for watchdog operation, this system controller watchdog will call SMC to trap to EL3 secure world ARM-Trusted-Firmware and then it will request system controller to do the watchdog operation via IPC. Below are the patch dependency: The dt-binding and imx8qxp.dtsi patch are based on my thermal patch series as below: https://patchwork.kernel.org/patch/10800699/ Anson Huang (4): dt-bindings: fsl: scu: add watchdog binding watchdog: imx_sc: Add i.MX system controller watchdog support arm64: defconfig: add support for i.MX system controller watchdog arm64: dts: freescale: imx8qxp: add watchdog support .../devicetree/bindings/arm/freescale/fsl,scu.txt | 10 + arch/arm64/boot/dts/freescale/imx8qxp.dtsi | 4 + arch/arm64/configs/defconfig | 1 + drivers/watchdog/Kconfig | 13 ++ drivers/watchdog/Makefile | 1 + drivers/watchdog/imx_sc_wdt.c | 210 +++++++++++++++++++++ 6 files changed, 239 insertions(+) create mode 100644 drivers/watchdog/imx_sc_wdt.c -- 2.7.4
