Hi Fu Wei,
On 25/08/2015:01:01:15 AM, fu.wei@linaro.org wrote:
From: Fu Wei fu.wei@linaro.org
This patchset: (1)Introduce Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt for FDT info of SBSA Generic Watchdog, and give two examples of adding SBSA Generic Watchdog device node into the dts files: foundation-v8.dts and amd-seattle-soc.dtsi.
(2)Introduce "pretimeout" into the watchdog framework, and update Documentation/watchdog/watchdog-kernel-api.txt to introduce: (1)the new elements in the watchdog_device and watchdog_ops struct; (2)the new API "watchdog_init_timeouts". (3)Introduce ARM SBSA watchdog driver: a.Use linux kernel watchdog framework; b.Work with FDT on ARM64; c.Use "pretimeout" in watchdog framework; d.Support getting timeout and pretimeout from parameter and FDT at the driver init stage. e.In the first timeout, do panic to save system context; f.In the second stage, user can still feed the dog without cleaning WS0. By this feature, we can avoid the panic infinite loops, while backing up a large system context in a server. g.In the second stage, can trigger WS1 by setting pretimeout = 0 if necessary. (4)Introduce ACPI GTDT parser: drivers/acpi/gtdt.c Parse SBSA Generic Watchdog Structure in GTDT table of ACPI, and create a platform device with that information. This platform device can be used by This Watchdog driver. drivers/clocksource/arm_arch_timer.c is simplified by this GTDT support.This patchset has been tested with watchdog daemon (ACPI/FDT, module/build-in) on the following platforms: (1)ARM Foundation v8 model
I tested it with kdump on fedora-arm64 Seattle platform. I enabled watchdog using systemd (with 30s timeout), insured that watchdog is active and then crashed the system. I can see that kdump kernel loads sbsa_wdt and activates watchdog, still vmcore copy is done successfully. My test kernel is here [1]
~Pratyush
[1] https://github.com/pratyushanand/linux/commits/wdt/sbsa-test-kexec