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Commit 2abd5f1b authored by Joel Fernandes's avatar Joel Fernandes Committed by Vinod Koul
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dma: edma: Increase maximum SG limit to 20 



davinci-pcm uses 16 as the no.of periods. With this, in EDMA we have to
allocate atleast 17 slots: 1 slot for channel, and 16 slots the periods.

Due to this, the MAX_NR_SG limitation causes problems, set it to 20 to make
cyclic DMA work when davinci-pcm is converted to use DMA Engine. Also add
a comment clarifying this.

Signed-off-by: default avatarJoel Fernandes <joelf@ti.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent fd009035

drivers/dma/edma.c

+8 −2
Original line number Diff line number Diff line
@@ -46,8 +46,14 @@ 
#define EDMA_CHANS	64

#endif /* CONFIG_ARCH_DAVINCI_DA8XX */



/* Max of 16 segments per channel to conserve PaRAM slots */

#define MAX_NR_SG		16

/*

 * Max of 20 segments per channel to conserve PaRAM slots

 * Also note that MAX_NR_SG should be atleast the no.of periods

 * that are required for ASoC, otherwise DMA prep calls will

 * fail. Today davinci-pcm is the only user of this driver and

 * requires atleast 17 slots, so we setup the default to 20.

 */

#define MAX_NR_SG		20

#define EDMA_MAX_SLOTS		MAX_NR_SG

#define EDMA_DESCRIPTORS	16