| Message ID | 1379977515-3794-4-git-send-email-joelf@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Sep 23, 2013 at 06:05:15PM -0500, Joel Fernandes wrote: > 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. Applied, thanks -- ~Vinod
diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index 9b63e1e..407b496 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -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
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> --- drivers/dma/edma.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)