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-rw-r--r--drivers/dma/dmaengine.c2
-rw-r--r--include/linux/dmaengine.h9
2 files changed, 10 insertions, 1 deletions
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);
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index c61d4ca27bc..32cd84b4747 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -67,10 +67,11 @@ enum dma_transaction_type {
DMA_PRIVATE,
DMA_ASYNC_TX,
DMA_SLAVE,
+ DMA_CYCLIC,
};
/* last transaction type for creation of the capabilities mask */
-#define DMA_TX_TYPE_END (DMA_SLAVE + 1)
+#define DMA_TX_TYPE_END (DMA_CYCLIC + 1)
/**
@@ -422,6 +423,9 @@ struct dma_tx_state {
* @device_prep_dma_memset: prepares a memset operation
* @device_prep_dma_interrupt: prepares an end of chain interrupt operation
* @device_prep_slave_sg: prepares a slave dma operation
+ * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio.
+ * The function takes a buffer of size buf_len. The callback function will
+ * be called after period_len bytes have been transferred.
* @device_control: manipulate all pending operations on a channel, returns
* zero or error code
* @device_tx_status: poll for transaction completion, the optional
@@ -478,6 +482,9 @@ struct dma_device {
struct dma_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, enum dma_data_direction direction,
unsigned long flags);
+ struct dma_async_tx_descriptor *(*device_prep_dma_cyclic)(
+ struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
+ size_t period_len, enum dma_data_direction direction);
int (*device_control)(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
unsigned long arg);