Re: [linux-sunxi] Re: [PATCH v3 02/12] arm64: allwinner: a64: add NMI controller on A64

[icenowy]

å 2017-04-24 15:17ïMaxime Ripard åéï
> On Thu, Apr 20, 2017 at 03:03:38PM +0800, icenowy@xxxxxxx wrote:
> > å 2017-04-20 13:58ïMaxime Ripard åéï
> > > On Tue, Apr 18, 2017 at 06:56:43PM +0800, Icenowy Zheng wrote:
> > > >
> > > >
> > > > ä 2017å4æ18æ GMT+08:00 äå3:00:16, Maxime Ripard
> > > > <maxime.ripard@xxxxxxxxxxxxxxxxxx> åå:
> > > > >On Mon, Apr 17, 2017 at 07:57:37PM +0800, Icenowy Zheng wrote:
> > > > >> Allwinner A64 SoC features a NMI controller, which is usually
> > > > >connected
> > > > >> to the AXP PMIC.
> > > > >>
> > > > >> Add support for it.
> > > > >>
> > > > >> Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx>
> > > > >> Acked-by: Chen-Yu Tsai <wens@xxxxxxxx>
> > > > >> ---
> > > > >> Changes in v2:
> > > > >> - Added Chen-Yu's ACK.
> > > > >>
> > > > >>  arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 8 ++++++++
> > > > >>  1 file changed, 8 insertions(+)
> > > > >>
> > > > >> diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
> > > > >b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
> > > > >> index 05ec9fc5e81f..53c18ca372ea 100644
> > > > >> --- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
> > > > >> +++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
> > > > >> @@ -403,6 +403,14 @@
> > > > >>  				     <GIC_SPI 41 IRQ_TYPE_LEVEL_HIGH>;
> > > > >>  		};
> > > > >>
> > > > >> +		nmi_intc: interrupt-controller@01f00c0c {
> > > > >> +			compatible = "allwinner,sun6i-a31-sc-nmi";
> > > > >> +			interrupt-controller;
> > > > >> +			#interrupt-cells = <2>;
> > > > >> +			reg = <0x01f00c0c 0x38>;
> > > > >
> > > > >The base address is not correct, and there's uncertainty on whether
> > > > >this is this particular controller or not. Did you even test this?
> > > >
> > > > Tested by axp20x-pek.
> > >
> > > Still, the base address is wrong, which is yet another hint that this
> > > is not the same interrupt controller, and just works by accident.
> >
> > No, it's the same as other post-sun6i device trees.
> > See other post-sun6i device trees: (or maybe they're all wrong, but
> > as we have no document for it, we should temporarily keep them)
> >
> > sun6i-a31.dtsi
> > ```
> > 		nmi_intc: interrupt-controller@01f00c0c {
> > 			compatible = "allwinner,sun6i-a31-sc-nmi";
> > 			interrupt-controller;
> > 			#interrupt-cells = <2>;
> > 			reg = <0x01f00c0c 0x38>;
> > 			interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>;
> > 		};
> > ```
> >
> > sun8i-a23-a33.dtsi
> > ```
> > 		nmi_intc: interrupt-controller@01f00c0c {
> > 			compatible = "allwinner,sun6i-a31-sc-nmi";
> > 			interrupt-controller;
> > 			#interrupt-cells = <2>;
> > 			reg = <0x01f00c0c 0x38>;
> > 			interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>;
> > 		};
> > ```
> >
> > But according to the BSP device tree, the base address should be
> > 0x01f00c00. Should I send some patch to fix all of them? (but it will
> > break device tree compatibility)
>
> I'm really not a big fan of "if we see something that is broken, just
> let it rot" to be honest.
>
> We have no idea how this controller works exactly, just like we have
> no idea if it is exactly the same controller or not.
>
> The only thing we have today is the memory map, and it tells us that
> it has more registers than what you express here.
>
> Because of the DT backward compatibility, you have to think of it the
> other way around: what will happen if it turns out we need to setup
> any register outside of that region you described in the DT, in
> something like a year or so?
>
> We can't, really. While if you have the full memory region from the
> beginning, then you just have to add a single writel in your driver.

So things are now already broken, and we may need to fix also A31 and
A23/33.

How should we do this?

> Maxime
>
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