dma: edma: Increase maximum SG limit to 20 (2abd5f1b) · Commits · 戴 / test

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:

Joel Fernandes <joelf@ti.com> Signed-off-by:

Vinod Koul <vinod.koul@intel.com>

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

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