On Mon, 2019-11-04 at 18:09 +0100, Stefan Wahren wrote:
> Hi Nicolas,
>
> Am 04.11.19 um 14:54 schrieb Nicolas Saenz Julienne:
> > arm64 places the CMA in ZONE_DMA32, which is not good enough for the
> > Raspberry Pi 4 since it contains peripherals that can only address the
> > first GB of memory. Explicitly place the CMA into that area.
> >
> > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
>
> do you want this in Linux 5.5 via devicetree/fixes? In this case please
> add an fixes tag.
This has to go into v5.5 if the second patch is accepted. That said I can't add
a fixes tag as the code being fixed isn't yet in linus' tree.
Any suggestions? Maybe go through Catalin's tree?
> Otherwise this will be queued for Linux 5.6.
>
> > ---
> > arch/arm/boot/dts/bcm2711-rpi-4-b.dts | 19 +++++++++++++++++++
> > 1 file changed, 19 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> > b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> > index cccc1ccd19be..3c7833e9005a 100644
> > --- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> > +++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
> > @@ -19,6 +19,25 @@
> > reg = <0 0 0>;
> > };
> >
> > + reserved-memory {
> > + #address-cells = <2>;
> > + #size-cells = <1>;
> > + ranges;
> > +
> > + /*
> > + * arm64 reserves the CMA by default somewhere in ZONE_DMA32,
> > + * that's not good enough for the Raspberry Pi 4 as some
> > + * devices can only address the lower 1G of memory (ZONE_DMA).
> > + */
> > + linux,cma {
> > + compatible = "shared-dma-pool";
> > + size = <0x2000000>; /* 32MB */
> > + alloc-ranges = <0x0 0x00000000 0x40000000>;
> > + reusable;
> > + linux,cma-default;
> > + };
> > + };
> > +
>
> i think this is a SoC-specific issue not a board specifc one. Please
> move this to bcm2711.dtsi
Noted, thanks!
Regards,
Nicolas
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