[PATCH 5/5] Add DMA engine driver for Freescale MPC85xx processors.

[Nelson, Shannon]

>From: Scott Wood [mailto:scottwood at freescale.com] 
>Sent: Tuesday, September 11, 2007 7:20 AM
>To: Zhang Wei-r63237
>Cc: Nelson, Shannon; paulus at samba.org; 
>linuxppc-dev at ozlabs.org; Williams, Dan J; linux-kernel at vger.kernel.org
>Subject: Re: [PATCH 5/5] Add DMA engine driver for Freescale 
>MPC85xx processors.
>
>On Tue, Sep 11, 2007 at 06:10:53PM +0800, Zhang Wei-r63237 wrote:
>> > >+
>> > >+	fsl_dma_memcpy_issue_pending(chan);
>> > >+	while (fsl_dma_is_complete(chan, cookie, NULL, NULL)
>> > >+			!= DMA_SUCCESS);
>> > 
>> > Again, is it possible to hang your thread here?
>> > 
>> > [...]
>> 
>> I'll add msleep here.
>
>I think what was being sought was a timout, causing the test to return
>failure.
>
>-Scott
>

Either a timeout to stop the polling, or msleep() followed by a single
call to fsl_dma_is_complete().  However, using the msleep() method is
likely to be kinder to the rest of the kernel than polling for very
long.

sln