Re: [PATCH 02/11] dt-bindings: serial: snps-dw-apb-uart: Relax dma-names order constraint

[Rob Herring]

On Fri, Mar 17, 2023 at 12:21:41PM +0200, Cristian Ciocaltea via Alsa-devel wrote:
> Date: Fri, 17 Mar 2023 12:21:41 +0200
> From: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>
> To: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>, Sudeep Holla
>  <sudeep.holla@xxxxxxx>, Cristian Marussi <cristian.marussi@xxxxxxx>, Rob
>  Herring <robh+dt@xxxxxxxxxx>, Krzysztof Kozlowski
>  <krzysztof.kozlowski+dt@xxxxxxxxxx>, Greg Kroah-Hartman
>  <gregkh@xxxxxxxxxxxxxxxxxxx>, Liam Girdwood <lgirdwood@xxxxxxxxx>, Mark
>  Brown <broonie@xxxxxxxxxx>, Nicolas Frattaroli
>  <frattaroli.nicolas@xxxxxxxxx>, Heiko Stuebner <heiko@xxxxxxxxx>, Jaroslav
>  Kysela <perex@xxxxxxxx>, Takashi Iwai <tiwai@xxxxxxxx>, Paul Walmsley
>  <paul.walmsley@xxxxxxxxxx>, Palmer Dabbelt <palmer@xxxxxxxxxxx>, Albert Ou
>  <aou@xxxxxxxxxxxxxxxxx>, Daniel Drake <drake@xxxxxxxxxxxx>, Katsuhiro
>  Suzuki <katsuhiro@xxxxxxxxxxxxx>
> CC: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx, devicetree@xxxxxxxxxxxxxxx,
>  linux-kernel@xxxxxxxxxxxxxxx, linux-serial@xxxxxxxxxxxxxxx,
>  alsa-devel@xxxxxxxxxxxxxxxx, linux-rockchip@xxxxxxxxxxxxxxxxxxx,
>  linux-riscv@xxxxxxxxxxxxxxxxxxx, kernel@xxxxxxxxxxxxx
> Subject: Re: [PATCH 02/11] dt-bindings: serial: snps-dw-apb-uart: Relax
>  dma-names order constraint
> Message-ID: <8ae57fe3-56aa-7e50-3eaa-a12a40657baf@xxxxxxxxxxxxx>
> User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
>  Thunderbird/102.7.2

There is something strange going on with your mails as there are 2 
copies in the archives with the 2nd one getting the header twice. It's 
coming from the alsa-devel list.

> 
> On 3/17/23 10:31, Krzysztof Kozlowski wrote:
> > On 15/03/2023 12:47, Cristian Ciocaltea wrote:
> > > Commit 370f696e4474 ("dt-bindings: serial: snps-dw-apb-uart: add dma &
> > > dma-names properties") documented dma-names property to handle Allwiner
> > > D1 dtbs_check warnings, but relies on a strict rx->tx ordering, which is
> > > the reverse of what a different board expects:
> > > 
> > >    rk3326-odroid-go2.dtb: serial@ff030000: dma-names:0: 'rx' was expected
> > > 
> > > A quick and incomplete check shows the inconsistency is present in many
> > > other DT files:
> > 
> > Why not fixing the DTS? The properties should have fixed order.
> 
> I was initially concerned about the risk of a potential ABI breakage, but I
> think that's not really a problem since dma-names is not directly accessed
> in the driver and DT Kernel API doesn't rely on a particular order.
> 
> If there are no objections, I would switch the order in the binding to
> tx->rx, since that's what most of the DTS use, and fix the remaining ones.
> 
> > Best regards,
> > Krzysztof
> 
> Thanks,
> Cristian