Re: [Linaro-acpi] [PATCH v2 6/7] Watchdog: introduce ARM SBSA watchdog driver

Hi Guenter,

Great thanks :-)

On 21 May 2015 at 23:18, Guenter Roeck linux@roeck-us.net wrote:

On Thu, May 21, 2015 at 07:08:34PM +0800, Fu Wei wrote:

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Hi Guenter,

Thanks for review :-)

On 21 May 2015 at 18:34, Guenter Roeck linux@roeck-us.net wrote:

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On 05/21/2015 01:32 AM, fu.wei@linaro.org wrote:

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From: Fu Wei fu.wei@linaro.org

This driver bases on linux kernel watchdog framework, and use "pretimeout" in the framework. It supports getting timeout and pretimeout from parameter and FDT at the driver init stage. In first timeout(WS0), the interrupt routine run panic to save system context.

Signed-off-by: Fu Wei fu.wei@linaro.org

drivers/watchdog/Kconfig | 12 ++ drivers/watchdog/Makefile | 1 + drivers/watchdog/sbsa_gwdt.c | 476 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 489 insertions(+) create mode 100644 drivers/watchdog/sbsa_gwdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index e5e7c55..25a0df1 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -152,6 +152,18 @@ config ARM_SP805_WATCHDOG ARM Primecell SP805 Watchdog timer. This will reboot your system when the timeout is reached.

+config ARM_SBSA_WATCHDOG

•   tristate "ARM SBSA Generic Watchdog"
  

•   depends on ARM || ARM64 || COMPILE_TEST
  

•   depends on ARM_ARCH_TIMER
  

•   select WATCHDOG_CORE
  

•   help
  

•     ARM SBSA Generic Watchdog timer. This has two Watchdog Signals
  

•     (WS0/WS1), will trigger a warning interrupt(do panic) at the
  

first

•     timeout(WS0); will reboot your system when the second
  

timeout(WS1)

•     is reached.
  

I think it would be better to keep the WS0/WS1 out of the help text. It is an implementation detail, and no user will be able to make sense of it.

I don't mind to delete it , but those are in SBSA spec, is that an implementation detail ?

I think so.

Ask yourself - assuming you are not involved in the development of this driver, and you read this help text. Is the help text going to help you to know about WS0 and WS1 ? Why not just something like the following, if you want to be verbose ?

    ARM SBSA Generic Watchdog. This watchdog has two Watchdog timeouts.
    The first timeout will trigger a panic; the second timeout will trigger
    a system reset.

Great thanks, that is better, yes, If I never read SBSA spec, I don't know WS is watchdog signal :-)

Anyway, not worth arguing about.

yes, agree , Thanks for the example "help" :-)

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•   /*
  

•    * Try to determine the frequency from the arch_timer interface
  

•    */
  

•   clk = arch_timer_get_rate();
  

arch_timer_get_rate() does not seem to be exported. Did you try to build the driver as module ?

yes, I have built it as a ko module, that is why I made a patch to export this interface in the first patch of this patchset

but I will confirm it again :-)

Guess I'll give it a try myself. I don't really understand how this can work unless arch_timer_get_rate() is exported in your tree.

yes, I have exported it , I think it make sense to export it. Because other driver maybe need to get system counter info

Do you agree ? :-)

Guenter