linux-kernel - Re: [PATCH 7/8] dmaengine/dw_dmac: Unmap all memory buffers after completion of slave transfers

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Date:	Thu, 19 Jan 2012 18:34:56 +0100
From:	Linus Walleij <linus.walleij@...aro.org>
To:	Viresh Kumar <viresh.kumar@...com>
Cc:	Russell King - ARM Linux <linux@....linux.org.uk>,
	"vinod.koul@...el.com" <vinod.koul@...el.com>,
	"dan.j.williams@...el.com" <dan.j.williams@...el.com>,
	Pratyush ANAND <pratyush.anand@...com>,
	Rajeev KUMAR <rajeev-dlh.kumar@...com>,
	Bhupesh SHARMA <bhupesh.sharma@...com>,
	Armando VISCONTI <armando.visconti@...com>,
	Mirko GARDI <mirko.gardi@...com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Vipin KUMAR <vipin.kumar@...com>,
	Shiraz HASHIM <shiraz.hashim@...com>,
	Amit VIRDI <Amit.VIRDI@...com>,
	Vipul Kumar SAMAR <vipulkumar.samar@...com>,
	"viresh.linux@...il.com" <viresh.linux@...il.com>,
	Deepak SIKRI <deepak.sikri@...com>,
	Bhavna YADAV <bhavna.yadav@...com>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Vincenzo FRASCINO <Vincenzo.FRASCINO@...com>
Subject: Re: [PATCH 7/8] dmaengine/dw_dmac: Unmap all memory buffers after
 completion of slave transfers

On Tue, Jan 17, 2012 at 10:07 AM, Viresh Kumar <viresh.kumar@...com> wrote:

>> Why do you want to do this?
>
> This is because people can pass in flags which are
> DMA_COMPL_SKIP_SRC_UNMAP, etc.
>
> If they are not passed, then DMA driver must do it for them.

OK I see why it's confusing.

That flag is only for memcpy jobs.

Only memcpy jobs maps/unmaps buffers.

Slave transfers are mapped/unmapped by the driver.

Yours,
Linus Walleij
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