Re: [PATCH 02/12] bcm2835-dma: Add proper 40-bit DMA support

[Stefan Wahren]

Hi Dave and Andrea,

Am 06.02.24 um 17:31 schrieb Dave Stevenson:
> Hi Stefan and Andrea
>
> On Mon, 5 Feb 2024 at 18:50, Stefan Wahren <wahrenst@xxxxxxx> wrote:
> > Hi Andrea,
> >
> > [add Dave]
> >
> > Am 04.02.24 um 07:59 schrieb Andrea della Porta:
> > > From: Phil Elwell <phil@xxxxxxxxxxxxxxx>
> > >
> > > BCM2711 has 4 DMA channels with a 40-bit address range, allowing them
> > > to access the full 4GB of memory on a Pi 4.
> > >
> > > Cc: Phil Elwell <phil@xxxxxxxxxxxxxxx>
> > > Cc: Maxime Ripard <maxime@xxxxxxxxxx>
> > > Signed-off-by: Andrea della Porta <andrea.porta@xxxxxxxx>
> > mainlining isn't that simple by sending just the downstream patches to
> > the mailing list. In many cases there reasons why this hasn't been
> > upstreamed yet.
> >
> > In my opinion just this feature is worth a separate patch series. In
> > 2021 i already send an initial version, which tried to implement it in a
> > cleaner & maintainabler way [1]. In the meantime Dave Stevenson from
> > Raspberry Pi wrote that he also wanted to work on this. Maybe you want
> > to work on this together?
> Yes, I'm looking at reworking Stefan's series to work on Pi4 & Pi5 as
> it's needed for HDMI audio (and other things) on those platforms which
> I'm working to upstream.
>
> I was getting weirdness from the sdhci block when I was last looking
> at it, so it was just proving a little trickier than first thought.
> Hopefully I'll get some time on it in the next couple of weeks.
i must confess that my series was just a draft to see that the general
approach would be accepted. Yes, it's possible that there are issues :-(

Maybe i can help you a little bit by taking care of first two patches
(node name fix & YAML conversion)?

Regards
>    Dave
>
> > [1] -
> > https://lore.kernel.org/linux-arm-kernel/13ec386b-2305-27da-9765-8fa3ad71146c@xxxxxxxx/T/