diff options
| author | Sascha Hauer <s.hauer@pengutronix.de> | 2010-09-30 15:56:32 +0200 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2010-10-06 00:49:26 +0200 |
| commit | 782bc950d84e404422ba21008fd51ee894c8d231 (patch) | |
| tree | c8a10b80bcc571c6de8a19c39b0f447ca61039d6 /drivers | |
| parent | Linux 2.6.36-rc5 (diff) | |
| download | linux-782bc950d84e404422ba21008fd51ee894c8d231.tar.xz linux-782bc950d84e404422ba21008fd51ee894c8d231.zip | |
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 <s.hauer@pengutronix.de>
Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/dma/dmaengine.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 9d31d5eb95c1..e5e79ced4f4b 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); |