[PATCH 1/2] spi: atmel: convert to dma_request_slave_channel_compat()

[Ludovic Desroches]

On Fri, May 31, 2013 at 05:01:59PM +0200, Richard Genoud wrote:
> Use generic DMA DT helper.
> Platforms booting with or without DT populated are both supported.
> 
> Based on Ludovic Desroches <ludovic.desroches at atmel.com> patchset
> "ARM: at91: move to generic DMA device tree binding"
> 
> Signed-off-by: Richard Genoud <richard.genoud at gmail.com>

Looks fine for me to so
Acked-by: Ludovic Desroches <ludovic.desroches at gmail.com>

One comment below

> ---
>  drivers/spi/spi-atmel.c |   42 +++++++++++++++++++++++++++---------------
>  1 file changed, 27 insertions(+), 15 deletions(-)
> 
> rebased on linux-next next-20130531
> 
> diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
> index 31cfc87..ea1ec00 100644
> --- a/drivers/spi/spi-atmel.c
> +++ b/drivers/spi/spi-atmel.c
> @@ -424,10 +424,15 @@ static int atmel_spi_dma_slave_config(struct atmel_spi *as,
>  	return err;
>  }
>  
> -static bool filter(struct dma_chan *chan, void *slave)
> +static bool filter(struct dma_chan *chan, void *pdata)
>  {
> -	struct	at_dma_slave *sl = slave;
> +	struct atmel_spi_dma *sl_pdata = pdata;
> +	struct at_dma_slave *sl;
>  
> +	if (!sl_pdata)
> +		return false;
> +
> +	sl = &sl_pdata->dma_slave;
>  	if (sl->dma_dev == chan->device->dev) {

I am wondering if a null pointer dereference can happen here. In
atmel_spi_configure_dma sdata was checked so maybe sl should be check
here.

>  		chan->private = sl;
>  		return true;
> @@ -438,24 +443,31 @@ static bool filter(struct dma_chan *chan, void *slave)
>  
>  static int atmel_spi_configure_dma(struct atmel_spi *as)
>  {
> -	struct at_dma_slave *sdata = &as->dma.dma_slave;
>  	struct dma_slave_config	slave_config;
> +	struct device *dev = &as->pdev->dev;
>  	int err;
>  
> -	if (sdata && sdata->dma_dev) {
> -		dma_cap_mask_t mask;
> +	dma_cap_mask_t mask;
> +	dma_cap_zero(mask);
> +	dma_cap_set(DMA_SLAVE, mask);
>  
> -		/* Try to grab two DMA channels */
> -		dma_cap_zero(mask);
> -		dma_cap_set(DMA_SLAVE, mask);
> -		as->dma.chan_tx = dma_request_channel(mask, filter, sdata);
> -		if (as->dma.chan_tx)
> -			as->dma.chan_rx =
> -				dma_request_channel(mask, filter, sdata);
> +	as->dma.chan_tx = dma_request_slave_channel_compat(mask, filter,
> +							   &as->dma,
> +							   dev, "tx");
> +	if (!as->dma.chan_tx) {
> +		dev_err(dev,
> +			"DMA TX channel not available, SPI unable to use DMA\n");
> +		err = -EBUSY;
> +		goto error;
>  	}
> -	if (!as->dma.chan_rx || !as->dma.chan_tx) {
> -		dev_err(&as->pdev->dev,
> -			"DMA channel not available, SPI unable to use DMA\n");
> +
> +	as->dma.chan_rx = dma_request_slave_channel_compat(mask, filter,
> +							   &as->dma,
> +							   dev, "rx");
> +
> +	if (!as->dma.chan_rx) {
> +		dev_err(dev,
> +			"DMA RX channel not available, SPI unable to use DMA\n");
>  		err = -EBUSY;
>  		goto error;
>  	}
> -- 
> 1.7.10.4
>