Hi Marek,
On Sat, Sep 14, 2019 at 6:06 PM Marek Vasut <marek.vasut@xxxxxxxxx> wrote:
> On 9/9/19 1:18 PM, Geert Uytterhoeven wrote:
> > On Sat, Sep 7, 2019 at 6:16 PM Marek Vasut wrote:
> >> Add dma-ranges property into /soc node to describe the DMA capabilities
> >> of the bus. This is currently needed to translate PCI DMA ranges, which
> >> are limited to 32bit addresses.
> >
> >> --- a/arch/arm64/boot/dts/renesas/r8a7795.dtsi
> >> +++ b/arch/arm64/boot/dts/renesas/r8a7795.dtsi
> >> @@ -330,6 +330,7 @@
> >> #address-cells = <2>;
> >> #size-cells = <2>;
> >> ranges;
> >> + dma-ranges = <0 0x40000000 0 0x40000000 0 0xc0000000>;
> >
> > Shouldn't the length be 0x80000000 (for all SoCs)?
>
> Or should that match the amount of DRAM below 32bit boundary ?
Which is 0x80000000, according to the memory area section for the
various R-Car Gen3 SoCs.
> > Or should we allow DMA to internal System RAM, too?
>
> I think we should include SRAM, yes.
So that needs a separate range.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
