From mboxrd@z Thu Jan  1 00:00:00 1970
From: s.hauer@pengutronix.de (Sascha Hauer)
Date: Thu, 20 Jan 2011 11:28:08 +0100
Subject: [PATCH 5/6] dmaengine: imx-sdma: fix up param for the last BD
	in sdma_prep_slave_sg()
In-Reply-To: <1295473840-17295-6-git-send-email-shawn.guo@freescale.com>
References: <1295473840-17295-1-git-send-email-shawn.guo@freescale.com>
	<1295473840-17295-6-git-send-email-shawn.guo@freescale.com>
Message-ID: <20110120102808.GX9041@pengutronix.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Thu, Jan 20, 2011 at 05:50:39AM +0800, Shawn Guo wrote:
> As per the reference manual, bit "L" should be set while bit "C"
> should be cleared for the last buffer descriptor in the non-cyclic
> chain, so that sdma can stop trying to find the next BD and end
> the transfer.
> 
> In case of sdma_prep_slave_sg(), BD_LAST needs to be set and BD_CONT
> be cleared for the last BD.

Did you test this patch?

Sascha

> 
> Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
> ---
>  drivers/dma/imx-sdma.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
> index e5af547..fa63ace 100644
> --- a/drivers/dma/imx-sdma.c
> +++ b/drivers/dma/imx-sdma.c
> @@ -931,8 +931,11 @@ static struct dma_async_tx_descriptor *sdma_prep_slave_sg(
>  
>  		param = BD_DONE | BD_EXTD | BD_CONT;
>  
> -		if (i + 1 == sg_len)
> +		if (i + 1 == sg_len) {
>  			param |= BD_INTR;
> +			param |= BD_LAST;
> +			param &= ~BD_CONT;
> +		}
>  
>  		dev_dbg(sdma->dev, "entry %d: count: %d dma: 0x%08x %s%s\n",
>  				i, count, sg->dma_address,
> -- 
> 1.7.1
> 
> 
> 

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