Re: [PATCH v3 3/6] ARM: dts: sun8i: v3s: Add node for system control

[Martin Cerveny]

Hello.

On Thu, 3 Dec 2020, Chen-Yu Tsai wrote:

> Hi,
>
> On Mon, Nov 16, 2020 at 8:57 PM Martin Cerveny <m.cerveny@xxxxxxxxxxxx> wrote:
> > Allwinner V3s has system control and SRAM C1 region similar to H3.
> >
> > Signed-off-by: Martin Cerveny <m.cerveny@xxxxxxxxxxxx>
> > ---
> >  arch/arm/boot/dts/sun8i-v3s.dtsi | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/sun8i-v3s.dtsi b/arch/arm/boot/dts/sun8i-v3s.dtsi
> > index 0c7341676921..70193512c222 100644
> > --- a/arch/arm/boot/dts/sun8i-v3s.dtsi
> > +++ b/arch/arm/boot/dts/sun8i-v3s.dtsi
> > @@ -161,6 +161,20 @@ syscon: system-control@1c00000 {
> >                         #address-cells = <1>;
> >                         #size-cells = <1>;
> >                         ranges;
> > +
> > +                       sram_c: sram@1d00000 {
> > +                               compatible = "mmio-sram";
> > +                               reg = <0x01d00000 0x80000>;
>
> How was this address derived? Did you check that there is actually SRAM here?

Yes, I did some checking (mmap). But I repeated measurement and found 
mirrored regions:

- SRAM_C is mirrored from 0x0000_4000 (primary location) to 0x01d0_4000 (size 0xb000)
  (probably exact size is 0xb0c0)
- rest of 0x01d0_0000 are discontinuously filled with R/W register sets
  (probably some internals registers from VE) that I thought to be SRAM too
- register SRAM_CTRL_REG0==0x01c00_0000 (value 0x7fff_ffff) switch whole
  region 0x01d0_0000-0x01df_ffff __AND__ 0x0000_4000-0x0000_ffff
- VE/cedrus code use this regions indirectly
  (VE_AVC_SRAM_PORT_OFFSET/VE_AVC_SRAM_PORT_DATA...)
  and it is not influenced by "true" SRAM mapping or size

-> so I suppose to better use only SRAM_C lower definition:

---
diff --git a/arch/arm/boot/dts/sun8i-v3s.dtsi b/arch/arm/boot/dts/sun8i-v3s.dtsi
index e8f304125e2d..90d703e5b73b 100644
--- a/arch/arm/boot/dts/sun8i-v3s.dtsi
+++ b/arch/arm/boot/dts/sun8i-v3s.dtsi
@@ -162,17 +162,17 @@ syscon: system-control@1c00000 {
 			#size-cells = <1>;
 			ranges;

-			sram_c: sram@1d00000 {
+			sram_c: sram@4000 {
 				compatible = "mmio-sram";
-				reg = <0x01d00000 0x80000>;
+				reg = <0x4000 0xb000>;
 				#address-cells = <1>;
 				#size-cells = <1>;
-				ranges = <0 0x01d00000 0x80000>;
+				ranges = <0 0 0x4000 0xb000>;

 				ve_sram: sram-section@0 {
 					compatible = "allwinner,sun8i-v3s-sram-c1",
 						     "allwinner,sun4i-a10-sram-c1";
-					reg = <0x000000 0x80000>;
+					reg = <0x0 0xb000>;
 				};
 			};
 		};
---

Does someone have accessible specific documentation of VE/cedrus for V3s ?

Regards, Martin

> ChenYu
>
> > +                               #address-cells = <1>;
> > +                               #size-cells = <1>;
> > +                               ranges = <0 0x01d00000 0x80000>;
> > +
> > +                               ve_sram: sram-section@0 {
> > +                                       compatible = "allwinner,sun8i-v3s-sram-c1",
> > +                                                    "allwinner,sun4i-a10-sram-c1";
> > +                                       reg = <0x000000 0x80000>;
> > +                               };
> > +                       };
> >                 };
> >
> >                 tcon0: lcd-controller@1c0c000 {
> > --
> > 2.25.1
> >
> >
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