openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

dmaengine: dw: replace convert_burst() with one liner 

Replace convert_burst() with one liner in place.

The change simplifies further extension of the driver to cover new DMA
controller hardware.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Andy Shevchenko 2017-01-17 13:57:27 +02:00 committed by Vinod Koul
parent 08d62f58aa
commit be242f4e2e
1 changed files with 11 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/dma/dw/core.c
View File

@ -901,25 +901,18 @@ bool dw_dma_filter(struct dma_chan *chan, void *param)
}
EXPORT_SYMBOL_GPL(dw_dma_filter);
/*
* Fix sconfig's burst size according to dw_dmac. We need to convert them as:
* 1 -> 0, 4 -> 1, 8 -> 2, 16 -> 3.
*
* NOTE: burst size 2 is not supported by controller.
*
* This can be done by finding least significant bit set: n & (n - 1)
*/
static inline void convert_burst(u32 *maxburst)
{
if (*maxburst > 1)
*maxburst = fls(*maxburst) - 2;
else
*maxburst = 0;
}
static int dwc_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
struct dma_slave_config *sc = &dwc->dma_sconfig;
/*
* Fix sconfig's burst size according to dw_dmac. We need to convert
* them as:
* 1 -> 0, 4 -> 1, 8 -> 2, 16 -> 3.
*
* NOTE: burst size 2 is not supported by DesignWare controller.
*/
u32 s = 2;
/* Check if chan will be configured for slave transfers */
if (!is_slave_direction(sconfig->direction))
@ -928,8 +921,8 @@ static int dwc_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
memcpy(&dwc->dma_sconfig, sconfig, sizeof(*sconfig));
dwc->direction = sconfig->direction;
convert_burst(&dwc->dma_sconfig.src_maxburst);
convert_burst(&dwc->dma_sconfig.dst_maxburst);
sc->src_maxburst = sc->src_maxburst > 1 ? fls(sc->src_maxburst) - s : 0;
sc->dst_maxburst = sc->dst_maxburst > 1 ? fls(sc->dst_maxburst) - s : 0;
return 0;
}