Re: [PATCH 3/6] ARM: dts: sunxi: h3/h5: Add MBUS controller node

Jernej Škrabec
2019-09-12T20:28:46Z

Dne četrtek, 12. september 2019 ob 22:20:57 CEST je Maxime Ripard napisal(a):
> Hi,
>
> On Thu, Sep 12, 2019 at 07:51:29PM +0200, Jernej Skrabec wrote:
> > Both, H3 and H5, contain MBUS, which is the bus used by DMA devices to
> > access system memory.
> >
> > MBUS controller is responsible for arbitration between channels based
> > on set priority and can do some other things as well, like report
> > bandwidth used. It also maps RAM region to different address than CPU.
> >
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
> > ---
> >
> > arch/arm/boot/dts/sunxi-h3-h5.dtsi | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/sunxi-h3-h5.dtsi
> > b/arch/arm/boot/dts/sunxi-h3-h5.dtsi index eba190b3f9de..ef1d03812636
> > 100644
> > --- a/arch/arm/boot/dts/sunxi-h3-h5.dtsi
> > +++ b/arch/arm/boot/dts/sunxi-h3-h5.dtsi
> > @@ -109,6 +109,7 @@
> >
> > compatible = "simple-bus";
> > #address-cells = <1>;
> > #size-cells = <1>;
> >
> > + dma-ranges;
> >
> > ranges;
> >
> > display_clocks: clock@1000000 {
> >
> > @@ -538,6 +539,14 @@
> >
> > };
> >
> > };
> >
> > + mbus: dram-controller@1c62000 {
> > + compatible = "allwinner,sun8i-h3-mbus";
> > + reg = <0x01c62000 0x1000>;
> > + clocks = <&ccu 113>;
> > + dma-ranges = <0x00000000 0x40000000
0xc0000000>;
> > + #interconnect-cells = <1>;
> > + };
> > +
>
> If that's easy enough to access, can you also add the references in
> the devices that are already there? (CSI and DE comes to my mind, but
> there might be others).

Strangely, DE2 doesn't use this offset. That was tested on OrangePi Plus2E,
which has 2 GiB of RAM and subtracting this offset causes corrupted image.

But I can add this properties to CSI too. However, wouldn't that need CSI DT
binding expansion with those properties? othetwise DT check will fail.

Best regards,
Jernej

>
> Thanks!
> Maxime