linux-kernel - Re: [PATCH RFC 2/2] ARM: pxa: transition to dmaengine phase 1

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Date:	Mon, 16 Feb 2015 11:28:57 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	linux-arm-kernel@...ts.infradead.org
Cc:	Robert Jarzmik <robert.jarzmik@...e.fr>,
	Vinod Koul <vinod.koul@...el.com>,
	Olof Johansson <olof@...om.net>,
	Daniel Mack <zonque@...il.com>,
	Haojian Zhuang <haojian.zhuang@...il.com>,
	dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC 2/2] ARM: pxa: transition to dmaengine phase 1

On Saturday 14 February 2015 23:47:33 Robert Jarzmik wrote:
> @@ -294,7 +294,8 @@ int pxa_request_dma (char *name, pxa_dma_prio prio,
>                 /* try grabbing a DMA channel with the requested priority */
>                 for (i = 0; i < num_dma_channels; i++) {
>                         if ((dma_channels[i].prio == prio) &&
> -                           !dma_channels[i].name) {
> +                           !dma_channels[i].name &&
> +                           !mmp_pdma_toggle_reserved_channel(i)) {
>                                 found = 1;
>                                 break;
>                         }
> 

How is the order between the two enforced? I.e. can it be that the dmaengine
driver uses the same channel for a different slave before we get here?

If this is ensured to work, I'm fine with your approach.

	Arnd
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