From 782bc950d84e404422ba21008fd51ee894c8d231 Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Thu, 30 Sep 2010 13:56:32 +0000 Subject: dmaengine: add possibility for cyclic transfers Cyclic transfers are useful for audio where a single buffer divided in periods has to be transfered endlessly until stopped. After being prepared the transfer is started using the dma_async_descriptor->tx_submit function. dma_async_descriptor->callback is called after each period. The transfer is stopped using the DMA_TERMINATE_ALL callback. While being used for cyclic transfers the channel cannot be used for other transfer types. Signed-off-by: Sascha Hauer Cc: Haavard Skinnemoen Signed-off-by: Dan Williams --- drivers/dma/dmaengine.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/dma/dmaengine.c') diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 9d31d5eb95c..e5e79ced4f4 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -692,6 +692,8 @@ int dma_async_device_register(struct dma_device *device) !device->device_prep_dma_interrupt); BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) && !device->device_prep_slave_sg); + BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) && + !device->device_prep_dma_cyclic); BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) && !device->device_control); -- cgit v1.2.3