| Message ID | 1576153187-28378-3-git-send-email-xingyu.chen@amlogic.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | add meson secure watchdog driver | expand |
Hi Xingyu and Rob, On Thu, Dec 12, 2019 at 1:20 PM Xingyu Chen <xingyu.chen@amlogic.com> wrote: [...] > +examples: > + - | > + watchdog { > + compatible = "amlogic,meson-sec-wdt"; > + timeout-sec = <60>; > + }; in v3 of this patch Rob commented that there shouldn't be an OF node if there are no additional properties with timeout-sec there's now an additional property so my understanding is that it's fine to have an OF node what I don't understand yet is where this node should be placed. is it supposed to be a child node of the secure monitor node (for which we already have a binding here: Documentation/devicetree/bindings/firmware/meson/meson_sm.txt) or where else would we place it inside the .dts? Martin [0] https://patchwork.kernel.org/patch/11211399/
Hi, Martin Sorry for the late reply. On 2019/12/13 4:05, Martin Blumenstingl wrote: > Hi Xingyu and Rob, > > On Thu, Dec 12, 2019 at 1:20 PM Xingyu Chen <xingyu.chen@amlogic.com> wrote: > [...] >> +examples: >> + - | >> + watchdog { >> + compatible = "amlogic,meson-sec-wdt"; >> + timeout-sec = <60>; >> + }; > in v3 of this patch Rob commented that there shouldn't be an OF node > if there are no additional properties > with timeout-sec there's now an additional property so my > understanding is that it's fine to have an OF node Your understanding is correct. > > what I don't understand yet is where this node should be placed. > is it supposed to be a child node of the secure monitor node (for > which we already have a binding here: > Documentation/devicetree/bindings/firmware/meson/meson_sm.txt) or > where else would we place it inside the .dts? IMO, Although the watchdog node need to reference the meson_sm node, there is no bus-like dependencies between the devices which the two nodes corresponding to. so i think that the watchdog node as child node of meson_sm maybe not appropriate. > > > Martin > > > [0] https://patchwork.kernel.org/patch/11211399/ > > . >
On 12/15/19 10:03 PM, Xingyu Chen wrote: > Hi, Martin > > Sorry for the late reply. > > On 2019/12/13 4:05, Martin Blumenstingl wrote: >> Hi Xingyu and Rob, >> >> On Thu, Dec 12, 2019 at 1:20 PM Xingyu Chen <xingyu.chen@amlogic.com> wrote: >> [...] >>> +examples: >>> + - | >>> + watchdog { >>> + compatible = "amlogic,meson-sec-wdt"; >>> + timeout-sec = <60>; >>> + }; >> in v3 of this patch Rob commented that there shouldn't be an OF node >> if there are no additional properties >> with timeout-sec there's now an additional property so my >> understanding is that it's fine to have an OF node > Your understanding is correct. >> >> what I don't understand yet is where this node should be placed. >> is it supposed to be a child node of the secure monitor node (for >> which we already have a binding here: >> Documentation/devicetree/bindings/firmware/meson/meson_sm.txt) or >> where else would we place it inside the .dts? > IMO, Although the watchdog node need to reference the meson_sm node, there is no > bus-like dependencies between the devices which the two nodes corresponding to. > so i think that the watchdog node as child node of meson_sm maybe not appropriate. The watchdog driver needs the meson SM's dt node, and it depends on the existence of that node. That seems enough of a relationship to warrant having it as child note. Guenter
Hi, Guenter Martin On 2019/12/16 21:30, Guenter Roeck wrote: > On 12/15/19 10:03 PM, Xingyu Chen wrote: >> Hi, Martin >> >> Sorry for the late reply. >> >> On 2019/12/13 4:05, Martin Blumenstingl wrote: >>> Hi Xingyu and Rob, >>> >>> On Thu, Dec 12, 2019 at 1:20 PM Xingyu Chen >>> <xingyu.chen@amlogic.com> wrote: >>> [...] >>>> +examples: >>>> + - | >>>> + watchdog { >>>> + compatible = "amlogic,meson-sec-wdt"; >>>> + timeout-sec = <60>; >>>> + }; >>> in v3 of this patch Rob commented that there shouldn't be an OF node >>> if there are no additional properties >>> with timeout-sec there's now an additional property so my >>> understanding is that it's fine to have an OF node >> Your understanding is correct. >>> >>> what I don't understand yet is where this node should be placed. >>> is it supposed to be a child node of the secure monitor node (for >>> which we already have a binding here: >>> Documentation/devicetree/bindings/firmware/meson/meson_sm.txt) or >>> where else would we place it inside the .dts? >> IMO, Although the watchdog node need to reference the meson_sm node, >> there is no >> bus-like dependencies between the devices which the two nodes >> corresponding to. >> so i think that the watchdog node as child node of meson_sm maybe not >> appropriate. > > The watchdog driver needs the meson SM's dt node, and it depends on > the existence > of that node. That seems enough of a relationship to warrant having it > as child note. Thanks for your reply, if i take the wdt node as child of secure monitor (sm), how should i register or find the wdt device ? I only think of the following three methods : 1). update the sm driver，and scan®ister wdt device when the sm driver probes(It is like i2c), but there are too many changes involved. 2). add "simple-bus" key string to compatible of sm node, and it will make the child node is registered as platform device, but it seems that the key string is not match current scene. secure-monitor { compatible = "amlogic,meson-gxbb-sm", "simple-bus"; watchdog { compatible = "amlogic,meson-sec-wdt"; timeout-sec = <60>; } } 3). don't register device, and find directly the watchdog node by using the of_* API in watchdog driver (Eg: linux-4.x/drivers/tee/optee/core.c) secure-monitor { compatible = "amlogic,meson-gxbb-sm"; watchdog { compatible = "amlogic,meson-sec-wdt"; timeout-sec = <60>; } } The method 3 looks better for me, do you have a better suggestion ? Thanks BR > > Guenter > > . >
On Wed, Dec 18, 2019 at 03:37:49PM +0800, Xingyu Chen wrote: > Hi, Guenter Martin > > On 2019/12/16 21:30, Guenter Roeck wrote: > > On 12/15/19 10:03 PM, Xingyu Chen wrote: > > > Hi, Martin > > > > > > Sorry for the late reply. > > > > > > On 2019/12/13 4:05, Martin Blumenstingl wrote: > > > > Hi Xingyu and Rob, > > > > > > > > On Thu, Dec 12, 2019 at 1:20 PM Xingyu Chen > > > > <xingyu.chen@amlogic.com> wrote: > > > > [...] > > > > > +examples: > > > > > + - | > > > > > + watchdog { > > > > > + compatible = "amlogic,meson-sec-wdt"; > > > > > + timeout-sec = <60>; > > > > > + }; > > > > in v3 of this patch Rob commented that there shouldn't be an OF node > > > > if there are no additional properties > > > > with timeout-sec there's now an additional property so my > > > > understanding is that it's fine to have an OF node > > > Your understanding is correct. > > > > > > > > what I don't understand yet is where this node should be placed. > > > > is it supposed to be a child node of the secure monitor node (for > > > > which we already have a binding here: > > > > Documentation/devicetree/bindings/firmware/meson/meson_sm.txt) or > > > > where else would we place it inside the .dts? > > > IMO, Although the watchdog node need to reference the meson_sm > > > node, there is no > > > bus-like dependencies between the devices which the two nodes > > > corresponding to. > > > so i think that the watchdog node as child node of meson_sm maybe > > > not appropriate. > > > > The watchdog driver needs the meson SM's dt node, and it depends on the > > existence > > of that node. That seems enough of a relationship to warrant having it > > as child note. > Thanks for your reply, if i take the wdt node as child of secure monitor > (sm), how should > i register or find the wdt device ? > > I only think of the following three methods : > 1). update the sm driver，and scan®ister wdt device when the sm driver > probes(It is like i2c), but there > are too many changes involved. Just add of_platform_default_populate() call and clean-up calls. That's not what I'd call 'too many changes'. > 2). add "simple-bus" key string to compatible of sm node, and it will make > the child node is registered as > platform device, but it seems that the key string is not match current > scene. You previously said it's not a bus... > > secure-monitor { > compatible = "amlogic,meson-gxbb-sm", "simple-bus"; > > watchdog { > compatible = "amlogic,meson-sec-wdt"; > timeout-sec = <60>; > } > } > > 3). don't register device, and find directly the watchdog node by using the > of_* API in watchdog > driver (Eg: linux-4.x/drivers/tee/optee/core.c) > > secure-monitor { > compatible = "amlogic,meson-gxbb-sm"; > > watchdog { > compatible = "amlogic,meson-sec-wdt"; > timeout-sec = <60>; > } > } > > The method 3 looks better for me, do you have a better suggestion ? Thanks > > BR > > > > Guenter > > > > . > >
Hi, Rob On 2019/12/19 4:34, Rob Herring wrote: > On Wed, Dec 18, 2019 at 03:37:49PM +0800, Xingyu Chen wrote: >> Hi, Guenter Martin >> >> On 2019/12/16 21:30, Guenter Roeck wrote: >>> On 12/15/19 10:03 PM, Xingyu Chen wrote: >>>> Hi, Martin >>>> >>>> Sorry for the late reply. >>>> >>>> On 2019/12/13 4:05, Martin Blumenstingl wrote: >>>>> Hi Xingyu and Rob, >>>>> >>>>> On Thu, Dec 12, 2019 at 1:20 PM Xingyu Chen >>>>> <xingyu.chen@amlogic.com> wrote: >>>>> [...] >>>>>> +examples: >>>>>> + - | >>>>>> + watchdog { >>>>>> + compatible = "amlogic,meson-sec-wdt"; >>>>>> + timeout-sec = <60>; >>>>>> + }; >>>>> in v3 of this patch Rob commented that there shouldn't be an OF node >>>>> if there are no additional properties >>>>> with timeout-sec there's now an additional property so my >>>>> understanding is that it's fine to have an OF node >>>> Your understanding is correct. >>>>> what I don't understand yet is where this node should be placed. >>>>> is it supposed to be a child node of the secure monitor node (for >>>>> which we already have a binding here: >>>>> Documentation/devicetree/bindings/firmware/meson/meson_sm.txt) or >>>>> where else would we place it inside the .dts? >>>> IMO, Although the watchdog node need to reference the meson_sm >>>> node, there is no >>>> bus-like dependencies between the devices which the two nodes >>>> corresponding to. >>>> so i think that the watchdog node as child node of meson_sm maybe >>>> not appropriate. >>> The watchdog driver needs the meson SM's dt node, and it depends on the >>> existence >>> of that node. That seems enough of a relationship to warrant having it >>> as child note. >> Thanks for your reply, if i take the wdt node as child of secure monitor >> (sm), how should >> i register or find the wdt device ? >> >> I only think of the following three methods : >> 1). update the sm driver，and scan®ister wdt device when the sm driver >> probes(It is like i2c), but there >> are too many changes involved. > Just add of_platform_default_populate() call and clean-up calls. That's > not what I'd call 'too many changes'. Thanks for your guidance. > > >> 2). add "simple-bus" key string to compatible of sm node, and it will make >> the child node is registered as >> platform device, but it seems that the key string is not match current >> scene. > You previously said it's not a bus... > >> secure-monitor { >> compatible = "amlogic,meson-gxbb-sm", "simple-bus"; >> >> watchdog { >> compatible = "amlogic,meson-sec-wdt"; >> timeout-sec = <60>; >> } >> } >> >> 3). don't register device, and find directly the watchdog node by using the >> of_* API in watchdog >> driver (Eg: linux-4.x/drivers/tee/optee/core.c) >> >> secure-monitor { >> compatible = "amlogic,meson-gxbb-sm"; >> >> watchdog { >> compatible = "amlogic,meson-sec-wdt"; >> timeout-sec = <60>; >> } >> } >> >> The method 3 looks better for me, do you have a better suggestion ? Thanks >> >> BR >>> Guenter >>> >>> . >>> > . >
diff --git a/Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml b/Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml new file mode 100644 index 00000000..c0ff2ec --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml @@ -0,0 +1,35 @@ +# SPDX-License-Identifier: (GPL-2.0+ OR MIT) +# Copyright (c) 2019 Amlogic, Inc +%YAML 1.2 +--- +$id: "http://devicetree.org/schemas/power/amlogic,meson-sec-wdt.yaml#" +$schema: "http://devicetree.org/meta-schemas/core.yaml#" + +title: Amlogic Meson Secure Watchdog Timer + +maintainers: + - Xingyu Chen <xingyu.chen@amlogic.com> + +description: |+ + Secure Watchdog Timer used in Meson-A/C series Compatible SoCs + +properties: + compatible: + enum: + - amlogic,meson-sec-wdt + + timeout-sec: + minimum: 1 + maximum: 65 + description: + Watchdog timeout values (in seconds) + +required: + - compatible + +examples: + - | + watchdog { + compatible = "amlogic,meson-sec-wdt"; + timeout-sec = <60>; + };
The binding targets the Meson-A/C series compatible SoCs, in which the watchdog registers are in secure world. Signed-off-by: Xingyu Chen <xingyu.chen@amlogic.com> --- .../bindings/watchdog/amlogic,meson-sec-wdt.yaml | 35 ++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 Documentation/devicetree/bindings/watchdog/amlogic,meson-sec-wdt.yaml