Hi Mark Thanks for your rapid feedback, I appreciate your help very much. On 28 October 2015 at 00:22, Mark Rutland <mark.rutland@xxxxxxx> wrote: > On Wed, Oct 28, 2015 at 12:06:35AM +0800, fu.wei@xxxxxxxxxx wrote: >> From: Fu Wei <fu.wei@xxxxxxxxxx> >> >> The sbsa-gwdt.txt documentation in devicetree/bindings/watchdog is for >> introducing SBSA(Server Base System Architecture) Generic Watchdog >> device node info into FDT. >> >> Also add sbsa-gwdt introduction in watchdog-parameters.txt >> >> Acked-by: Arnd Bergmann <arnd@xxxxxxxx> >> Signed-off-by: Fu Wei <fu.wei@xxxxxxxxxx> >> --- >> .../devicetree/bindings/watchdog/sbsa-gwdt.txt | 46 ++++++++++++++++++++++ >> Documentation/watchdog/watchdog-parameters.txt | 6 +++ >> 2 files changed, 52 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt b/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt >> new file mode 100644 >> index 0000000..ad8e99a >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt >> @@ -0,0 +1,46 @@ >> +* SBSA (Server Base System Architecture) Generic Watchdog >> + >> +The SBSA Generic Watchdog Timer is used to force a reset of the system >> +after two stages of timeout have elapsed. A detailed definition of the >> +watchdog timer can be found in the ARM document: ARM-DEN-0029 - Server >> +Base System Architecture (SBSA) >> + >> +Required properties: >> +- compatible: Should at least contain "arm,sbsa-gwdt". >> + >> +- reg: Each entry specifies the base physical 64-bit address of a register >> + frame and the 64-bit length of that frame; currently, two frames must be > > Remove "64-bit" here. This depends on #address-cells and #size-cells, as > usual. Ah, right, Thanks , will do > >> + defined, in this order: >> + 1: Watchdog control frame >> + 2: Refresh frame. >> + >> +- interrupts: At least one interrupt must be defined that will be used as >> + the WS0 interrupt. A WS1 interrupt definition can be provided, but is >> + optional. The interrupts must be defined in this order: >> + 1: WS0 interrupt >> + 2: WS1 interrupt > > Why is WS1 optional? According to the description of WS1 in SBSA 2.3 (5.2 Watchdog Operation) page 21 ----------------- The signal is fed to a higher agent as an interrupt or reset for it to take executive action. ---------------- So WS1 maybe a interrupt. In a real Hardware, WS1 hooks to a reset signal pin of BMC, if this pin is triggered, BMC will do a real warm reset. In this case, WS1 is a reset, Linux doesn't need to deal with that. For now , I haven't found a hardware use WS1 as interrupt. In <ARM v8-A Foundation Platform User Guide> 3.2 Interrupt maps Page 22 Table 3-3 Shared peripheral interrupt assignments IRQ ID SPI offset Device 60 28 EL2 Generic Watchdog WS1 But I don't have further info about it. Anyway, because this signal could be interrupt or reset, Linux don't need know this signal sometimes. So I think it should be optional in binding info. Do I miss something? Any suggestion ? Please correct me, thanks. > >> +Optional properties >> +- timeout-sec: To use a timeout value that is different from the driver >> + default values, use this property. > > Either define a default value, or don't state anything about the > behaviour when this is not present. OK, thanks :-) > >> If used, at least one timeout value >> + (in seconds) must be provided. A second optional timeout value (in >> + seconds) may also be provided and will be used as the pre-timeout value, >> + if it is given. >> + >> + There are two possible sources for driver default timeout values: >> + (1) the driver contains hard-coded default values, or >> + (2) module parameters can be given when the module is loaded >> + >> + If timeout/pretimeout values are provided when the module loads, they >> + will take priority. Second priority will be the timeout-sec from DTB, >> + and third the hard-coded driver values. > > The last two paragraphs should go. They describe Linux behaviour rather > than the binding. yes, maybe that should be in the watchdog documentation? > > Thanks, > Mark. -- Best regards, Fu Wei Software Engineer Red Hat Software (Beijing) Co.,Ltd.Shanghai Branch Ph: +86 21 61221326(direct) Ph: +86 186 2020 4684 (mobile) Room 1512, Regus One Corporate Avenue,Level 15, One Corporate Avenue,222 Hubin Road,Huangpu District, Shanghai,China 200021 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
