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? > >> 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/ > 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 regards, Krzysztof
