Re: [PATCH 10/14] dma: mxs: Drop unnecessary flag

From: Vinod Koul <vkoul@kernel.org>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: kernel@pengutronix.de, Boris Brezillon <bbrezillon@kernel.org>,
	Richard Weinberger <richard@nod.at>,
	linux-mtd@lists.infradead.org, NXP Linux Team <linux-imx@nxp.com>,
	Fabio Estevam <festevam@gmail.com>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Han Xu <han.xu@nxp.com>, Shawn Guo <shawnguo@kernel.org>
Subject: Re: [PATCH 10/14] dma: mxs: Drop unnecessary flag
Date: Tue, 23 Apr 2019 10:52:33 +0530	[thread overview]
Message-ID: <20190423052233.GH28103@vkoul-mobl> (raw)
In-Reply-To: <20190409113421.3037-11-s.hauer@pengutronix.de>

On 09-04-19, 13:34, Sascha Hauer wrote:
> The mxs dma driver insists on having the DMA_PREP_INTERRUPT flag set
> on all but the first transfer. There's no need to let the user set this
> flag, the driver can do it internally whenever it needs it. Drop
> handling of this flag from the driver.

After changing patch title to dmaengine: mxs: ....

Acked-by: Vinod Koul <vkoul@kernel.org>

> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  drivers/dma/mxs-dma.c | 17 ++++++++---------
>  1 file changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
> index 22cc7f68ef6e..ce92a3626ea4 100644
> --- a/drivers/dma/mxs-dma.c
> +++ b/drivers/dma/mxs-dma.c
> @@ -477,16 +477,16 @@ static void mxs_dma_free_chan_resources(struct dma_chan *chan)
>   *            ......
>   *            ->device_prep_slave_sg(0);
>   *            ......
> - *            ->device_prep_slave_sg(DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
> + *            ->device_prep_slave_sg(DMA_CTRL_ACK);
>   *            ......
>   *    [3] If there are more than two DMA commands in the DMA chain, the code
>   *        should be:
>   *            ......
>   *            ->device_prep_slave_sg(0);                                // First
>   *            ......
> - *            ->device_prep_slave_sg(DMA_PREP_INTERRUPT [| DMA_CTRL_ACK]);
> + *            ->device_prep_slave_sg(DMA_CTRL_ACK]);
>   *            ......
> - *            ->device_prep_slave_sg(DMA_PREP_INTERRUPT | DMA_CTRL_ACK); // Last
> + *            ->device_prep_slave_sg(DMA_CTRL_ACK); // Last
>   *            ......
>   */
>  static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
> @@ -500,13 +500,12 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
>  	struct scatterlist *sg;
>  	u32 i, j;
>  	u32 *pio;
> -	bool append = flags & DMA_PREP_INTERRUPT;
> -	int idx = append ? mxs_chan->desc_count : 0;
> +	int idx = 0;
>  
> -	if (mxs_chan->status == DMA_IN_PROGRESS && !append)
> -		return NULL;
> +	if (mxs_chan->status == DMA_IN_PROGRESS)
> +		idx = mxs_chan->desc_count;
>  
> -	if (sg_len + (append ? idx : 0) > NUM_CCW) {
> +	if (sg_len + idx > NUM_CCW) {
>  		dev_err(mxs_dma->dma_device.dev,
>  				"maximum number of sg exceeded: %d > %d\n",
>  				sg_len, NUM_CCW);
> @@ -520,7 +519,7 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
>  	 * If the sg is prepared with append flag set, the sg
>  	 * will be appended to the last prepared sg.
>  	 */
> -	if (append) {
> +	if (idx) {
>  		BUG_ON(idx < 1);
>  		ccw = &mxs_chan->ccw[idx - 1];
>  		ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * idx;
> -- 
> 2.20.1

-- 
~Vinod

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