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Date: Tue, 6 Feb 2024 19:11:37 +0100
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Subject: Re: [PATCH 02/12] bcm2835-dma: Add proper 40-bit DMA support
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From: Stefan Wahren <wahrenst@gmx.net>
To: Dave Stevenson <dave.stevenson@raspberrypi.com>,
 Andrea della Porta <andrea.porta@suse.com>
Cc: Vinod Koul <vkoul@kernel.org>,
 Florian Fainelli <florian.fainelli@broadcom.com>, Ray Jui
 <rjui@broadcom.com>, Scott Branden <sbranden@broadcom.com>,
 Broadcom internal kernel review list
 <bcm-kernel-feedback-list@broadcom.com>, dmaengine@vger.kernel.org,
 linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org,
 linux-kernel@vger.kernel.org, Maxime Ripard <maxime@cerno.tech>,
 Dom Cobley <popcornmix@gmail.com>, Phil Elwell <phil@raspberrypi.com>
References: <cover.1706948717.git.andrea.porta@suse.com>
 <eeb94204c30c2182f5ffd3ec083c04399ecdee32.1706948717.git.andrea.porta@suse.com>
 <8736c115-e11c-41ca-85eb-7cd19a205068@gmx.net>
 <CAPY8ntCEvsTJwoEBYc7JsTaYfdMURhmytvvVMcLVNBkmdTNcZQ@mail.gmail.com>
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Am 06.02.24 um 19:08 schrieb 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@gmx.net> wrote:
>>> Hi Andrea,
>>>
>>> [add Dave]
>>>
>>> Am 04.02.24 um 07:59 schrieb Andrea della Porta:
>>>> From: Phil Elwell <phil@raspberrypi.org>
>>>>
>>>> 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@raspberrypi.org>
>>>> Cc: Maxime Ripard <maxime@cerno.tech>
>>>> Signed-off-by: Andrea della Porta <andrea.porta@suse.com>
>>> 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)?
Forget about this, it's already done
>
> Regards
>> =C2=A0=C2=A0 Dave
>>
>>> [1] -
>>> https://lore.kernel.org/linux-arm-kernel/13ec386b-2305-27da-9765-8fa3a=
d71146c@i2se.com/T/
>>>
>