Re: [PATCH] dmaengine: imx-sdma: Setting DMA_PRIVATE capability during the probe

From: Vinod Koul <vkoul@kernel.org>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Hui Wang <hui.wang@canonical.com>,
	dmaengine@vger.kernel.org, shawnguo@kernel.org,
	yibin.gong@nxp.com
Subject: Re: [PATCH] dmaengine: imx-sdma: Setting DMA_PRIVATE capability during the probe
Date: Fri, 1 Jul 2022 22:04:58 +0530	[thread overview]
Message-ID: <Yr8iMkBNMowEG+uF@matsya> (raw)
In-Reply-To: <20220620083310.GV2387@pengutronix.de>

On 20-06-22, 10:33, Sascha Hauer wrote:
> On Tue, May 24, 2022 at 03:49:33PM +0800, Hui Wang wrote:

> > +	dma_cap_set(DMA_PRIVATE, sdma->dma_device.cap_mask);
> 
> I am not sure about the impacts on the memcpy capability of the SDMA
> driver when setting this flag. It looks like this flag influences the
> way suitable channels are picked for memcpy, but I don't understand
> the code just by looking at it. I see that several other drivers
> providing memcpy set this flag as well, so I guess it's ok to set it,
> but it would be good to hear a word from Vinod about it.

So DMA_PRIVATE is used to make channel not available for general dma
allocation. So yes it would impact dma memcpy which is about allocating
generically.

-- 
~Vinod