[PATCH 1/2] DMA: fix AMBA PL08x driver issue with 64bit DMA address type

[Russell King - ARM Linux]

NAK.

On Wed, Aug 14, 2013 at 02:52:08PM +0200, Andre Przywara wrote:
> In Rob's recent pull request the patch
> 	ARM: highbank: select ARCH_DMA_ADDR_T_64BIT for LPAE
> promotes dma_addr_t to 64bit, which breaks compilation of the
> AMBA PL08x DMA driver.
> GCC has no function for the 64bit/8bit modulo operation.
> Looking more closely the divisor can only be 1, 2 or 4, so the full
> featured '%' modulo operation is overkill and can be replaced by
> simple bit masking.
> 
> Signed-off-by: Andre Przywara <andre.przywara at linaro.org>
> ---
>  drivers/dma/amba-pl08x.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
> index 06fe45c..29e1cf9 100644
> --- a/drivers/dma/amba-pl08x.c
> +++ b/drivers/dma/amba-pl08x.c
> @@ -286,6 +286,11 @@ static inline struct pl08x_txd *to_pl08x_txd(struct dma_async_tx_descriptor *tx)
>  	return container_of(tx, struct pl08x_txd, vd.tx);
>  }
>  
> +static int bus_addr_offset(struct pl08x_bus_data *bus)
> +{
> +	return bus->addr & (bus->buswidth - 1);
> +}
> +
>  /*
>   * Mux handling.
>   *
> @@ -886,8 +891,8 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
>  				return 0;
>  			}
>  
> -			if ((bd.srcbus.addr % bd.srcbus.buswidth) ||
> -					(bd.dstbus.addr % bd.dstbus.buswidth)) {
> +			if (bus_addr_offset(&bd.srcbus) ||
> +					bus_addr_offset(&bd.dstbus)) {
>  				dev_err(&pl08x->adev->dev,
>  					"%s src & dst address must be aligned to src"
>  					" & dst width if peripheral is flow controller",
> @@ -908,9 +913,8 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
>  		 */
>  		if (bd.remainder < mbus->buswidth)
>  			early_bytes = bd.remainder;
> -		else if ((mbus->addr) % (mbus->buswidth)) {
> -			early_bytes = mbus->buswidth - (mbus->addr) %
> -				(mbus->buswidth);
> +		else if (bus_addr_offset(mbus)) {
> +			early_bytes = mbus->buswidth - bus_addr_offset(mbus);
>  			if ((bd.remainder - early_bytes) < mbus->buswidth)
>  				early_bytes = bd.remainder;
>  		}
> @@ -928,7 +932,7 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
>  			 * Master now aligned
>  			 * - if slave is not then we must set its width down
>  			 */
> -			if (sbus->addr % sbus->buswidth) {
> +			if (bus_addr_offset(sbus)) {
>  				dev_dbg(&pl08x->adev->dev,
>  					"%s set down bus width to one byte\n",
>  					__func__);
> -- 
> 1.7.12.1
>