From: Vinod Koul <vkoul@kernel.org>
To: Frank Li <Frank.li@nxp.com>
Cc: Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Fabio Estevam <festevam@gmail.com>,
dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 0/6] dmaengine: Add common dma_slave_config and split it into src and dst parts
Date: Tue, 17 Mar 2026 15:56:40 +0530 [thread overview]
Message-ID: <abksYB2WQ0oNDSbS@vaman> (raw)
In-Reply-To: <aa7Y20I2_Hlp63gk@lizhi-Precision-Tower-5810>
On 09-03-26, 10:27, Frank Li wrote:
> On Mon, Mar 09, 2026 at 12:24:33PM +0100, Vinod Koul wrote:
> > On 14-01-26, 12:12, Frank Li wrote:
> > > Many DMA engine drivers store a dma_slave_config per channel. Propagate
> > > this configuration into struct dma_chan to avoid duplicating the same
> > > code in each driver.
> > >
> > > Much of dma_slave_config is identical for source and destination. Split
> > > the configuration into src and dst groups and use a union to preserve
> > > backward compatibility. This reduces the need for drivers to repeatedly
> > > check the DMA transfer direction.
> >
> > The reason why we had both the src/dstn sides was intended method to
> > allow upport ofr device to device dma. Some interest was shown for that
> > at that time.
> > I dont think we have such a user even now...
>
> My means is the field name is identical, not value identical although most
> case is the identical. but it is possible, especial FIFO space windows,
>
> sound/soc/fsl/fsl_asrc_dma.c use DEV_TO_DEV, at least src and addr use
> differece address.
Yeah so this would break if we go ahead. Thanks for looking this up
--
~Vinod
next prev parent reply other threads:[~2026-03-17 10:26 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-14 17:12 [PATCH 0/6] dmaengine: Add common dma_slave_config and split it into src and dst parts Frank Li
2026-01-14 17:12 ` [PATCH 1/6] dmaengine: Move struct dma_chan after struct dma_slave_config Frank Li
2026-01-14 17:12 ` [PATCH 2/6] dmaengine: Add common slave configuration to dma_chan Frank Li
2026-01-14 17:12 ` [PATCH 3/6] dmaengine: fsl-edma: use dma_chan common config Frank Li
2026-01-14 17:12 ` [PATCH 4/6] dmaengine: imx-sdma: use common config at dma_chan Frank Li
2026-01-14 17:12 ` [PATCH 5/6] dmaengine: Add union and dma_slave_get_config() helper for dma_slave_config Frank Li
2026-01-14 17:12 ` [PATCH 6/6] dmaengine: fsl-edma: use common dma_slave_get_cfg() Frank Li
2026-03-09 11:24 ` [PATCH 0/6] dmaengine: Add common dma_slave_config and split it into src and dst parts Vinod Koul
2026-03-09 14:27 ` Frank Li
2026-03-17 10:26 ` Vinod Koul [this message]
2026-03-17 13:56 ` Frank Li
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