Messages in this thread | | | Subject | Re: [PATCH 02/14] dt-bindings: soc: milbeaut: Add Milbeaut trampoline description | From | "Sugaya, Taichi" <> | Date | Mon, 3 Dec 2018 16:42:56 +0900 |
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Hi,
On 2018/11/30 17:16, Stephen Boyd wrote: > Quoting Sugaya, Taichi (2018-11-29 04:24:51) >> On 2018/11/28 11:01, Stephen Boyd wrote: >>> Quoting Sugaya Taichi (2018-11-18 17:01:07) >>>> create mode 100644 Documentation/devicetree/bindings/soc/socionext/socionext,m10v.txt >>>> >>>> diff --git a/Documentation/devicetree/bindings/soc/socionext/socionext,m10v.txt b/Documentation/devicetree/bindings/soc/socionext/socionext,m10v.txt >>>> new file mode 100644 >>>> index 0000000..f5d906c >>>> --- /dev/null >>>> +++ b/Documentation/devicetree/bindings/soc/socionext/socionext,m10v.txt >>>> @@ -0,0 +1,12 @@ >>>> +Socionext M10V SMP trampoline driver binding >>>> + >>>> +This is a driver to wait for sub-cores while boot process. >>>> + >>>> +- compatible: should be "socionext,smp-trampoline" >>>> +- reg: should be <0x4C000100 0x100> >>>> + >>>> +EXAMPLE >>>> + trampoline: trampoline@0x4C000100 { >>> Drop the 0x part of unit addresses. >> >> Okay. >> >> >>>> + compatible = "socionext,smp-trampoline"; >>>> + reg = <0x4C000100 0x100>; >>> Looks like a software construct, which we wouldn't want to put into DT >>> this way. DT doesn't describe drivers. >> We would like to use this node only getting the address of the >> trampoline area >> in which sub-cores wait. (They have finished to go to this area in previous >> bootloader process.) > > Is this area part of memory, or a special SRAM? If it's part of memory, > I would expect this node to be under the reserved-memory node and > pointed to by some other node that uses this region. Could even be the > CPU nodes.
Yes, 0x4C000100 is a part of memory under the reserved-memory node. So we would like to use the SRAM ( allocated 0x00000000 ) area instead. BTW, sorry, the trampoline address of this example is simply wrong. We were going to use a part of the SRAM from the beginning.
> >> >> So should we embed the constant value in source codes instead of getting >> from >> DT because the address is constant at the moment? Or is there other >> approach? >> > > If it's constant then that also works. Why does it need to come from DT > at all then?
We think it is not good to embed constant value in driver codes and do not have another way... Are there better ways?
Thanks Sugaya Taichi
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