Re: [PATCH v7 0/8] Watchdog: introduce ARM SBSA watchdog driver

From: Pratyush Anand
Date: Wed Sep 30 2015 - 13:13:50 EST

Hi Fu Wei,

On 25/08/2015:01:01:15 AM, fu.wei@xxxxxxxxxx wrote:
> From: Fu Wei <fu.wei@xxxxxxxxxx>
> 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]


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