Hi Krzysztof, > -----Original Message----- > From: Krzysztof Kozlowski <krzk@xxxxxxxxxx> > Sent: Monday, October 14, 2024 2:53 PM > Subject: Re: [PATCH 1/4] dt-bindings: watchdog: aspeed: Add property for WDT > SW reset > > On 14/10/2024 04:07, Chin-Ting Kuo wrote: > > Hi Krzysztof, > > > > Thanks for the review. > > > >> -----Original Message----- > >> From: Krzysztof Kozlowski <krzk@xxxxxxxxxx> > >> Sent: Monday, October 7, 2024 2:58 PM > >> Subject: Re: [PATCH 1/4] dt-bindings: watchdog: aspeed: Add property > >> for WDT SW reset > >> > >> On 07/10/2024 08:34, Chin-Ting Kuo wrote: > >>> Add "aspeed,restart-sw" property to distinguish normal WDT reset > >>> from system restart triggered by SW consciously. > >>> > >>> Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@xxxxxxxxxxxxxx> > >>> --- > >>> .../bindings/watchdog/aspeed,ast2400-wdt.yaml | 11 > >> +++++++++++ > >>> 1 file changed, 11 insertions(+) > >>> > >>> diff --git > >>> > a/Documentation/devicetree/bindings/watchdog/aspeed,ast2400-wdt.yaml > >>> > b/Documentation/devicetree/bindings/watchdog/aspeed,ast2400-wdt.yaml > >>> index be78a9865584..6cc3604c295a 100644 > >>> --- > >>> > a/Documentation/devicetree/bindings/watchdog/aspeed,ast2400-wdt.yaml > >>> +++ b/Documentation/devicetree/bindings/watchdog/aspeed,ast2400-wdt. > >>> +++ ya > >>> +++ ml > >>> @@ -95,6 +95,17 @@ properties: > >>> array with the first word defined using the > >>> AST2600_WDT_RESET1_* > >> macros, > >>> and the second word defined using the AST2600_WDT_RESET2_* > >> macros. > >>> > >>> + aspeed,restart-sw: > >>> + $ref: /schemas/types.yaml#/definitions/flag > >>> + description: > > >> > >> Why >? > >> > > > > ">" will be removed in the next patch series and the description > > content will be concatenated after the colon, ":". > > > >>> + Normally, ASPEED WDT reset may occur when system hangs or > >> reboot > >>> + triggered by SW consciously. However, system doesn't know > >>> + whether > >> the > >>> + restart is triggered by SW consciously since the reset event flag is > >>> + the same as normal WDT timeout reset. With this property, SW > >>> + can > >> > >> So DTS has this property and watchdog bites (timeout) but you will > >> ignore it and claim that it was software choice? > >> > > > > No. Normally, when WDT is enabled, a counter is also be enabled. When > > the counter is equal to an expected value, timeout event occurs. > > AST2600 hardware supports a SW mode, when a magic number is filled > > into a specific register, WDT reset is triggered immediately without > controlling the counter and the counter is not counted. > > Thus, WDT timeout doesn't occur. > > How is this a no? > It is used to emphasize that the driver doesn’t ignore the timeout event because the counter is not counted when SW mode is used and thus, no timeout occurs. > > > >> This does not make much sense to me, at least based on this > >> explanation > >> > >>> + restart the system immediately and directly without wait for WDT > >>> + timeout occurs. The reset event flag is also different from > >>> + the > >> normal > >>> + WDT reset. This property is only supported since AST2600 > platform. > >> > >> Supported as drivers? How is this related? Or you mean hardware? Then > >> property should be restricted there. > >> > > > > It is a hardware supported function on AST2600. For platform > > compatibility, without this property, all behaviors are the same as the > previous generation platform, AST2500. > > > > This property may be removed in the next patch series with referring > > to Rob suggestion > > s/may/will/ > This property will be removed in the next patch series. > > in the other reply. After checking with the major users, it is > > feasible to remove this property and using SW reset by default when > > the restart operation is triggered by SW deliberately on AST2600 platform. > > > > Best Wishes, Chin-Ting
