Re: [PATCH v2] spi: imx: keep dma request disabled before dma transfer setup

[Carlos Song]

> -----Original Message-----
> From: Fabio Estevam <festevam@xxxxxxxxx>
> Sent: Monday, October 27, 2025 8:13 PM
> To: Carlos Song <carlos.song@xxxxxxx>
> Cc: Frank Li <frank.li@xxxxxxx>; broonie@xxxxxxxxxx; shawnguo@xxxxxxxxxx;
> s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; linux-spi@xxxxxxxxxxxxxxx;
> imx@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: [EXT] Re: [PATCH v2] spi: imx: keep dma request disabled before dma
> transfer setup
> 
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> 
> On Mon, Oct 27, 2025 at 8:04 AM <carlos.song@xxxxxxx> wrote:
> >
> > From: Robin Gong <yibin.gong@xxxxxxx>
> >
> > Due to a hardware limitation on SDMA event enable (ENBLn), the DMA
> > request must remain disabled until the DMA transfer setup is complete.
> >
> > Refer SDMA 2.6.28 Channel Enable RAM (SDMAARMx_CHNENBLn) section:
> >
> > "
> > It is thus essential for the Arm platform to program them before any
> > DMA request is triggered to the SDMA, otherwise an unpredictable
> > combination of channels may be started.
> > "
> >
> > SDMA hardware configuration is postponed to transfer phase, so
> > enabling the DMA request too early may cause unpredictable channel
> activation.
> > Then keep dma request disabled before dma transfer setup.
> >
> > Signed-off-by: Carlos Song <carlos.song@xxxxxxx>
> > Signed-off-by: Robin Gong <yibin.gong@xxxxxxx>
> 
> Should this contain a Fixes tag?

Thank you, I will add this at next version patch.