async_tx: replace 'int_en' with operation preparation flags

Pass a full set of flags to drivers' per-operation 'prep' routines.
Currently the only flag passed is DMA_PREP_INTERRUPT.  The expectation is
that arch-specific async_tx_find_channel() implementations can exploit this
capability to find the best channel for an operation.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Shannon Nelson <shannon.nelson@intel.com>
Reviewed-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index b0864f5..acbb364 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -95,6 +95,15 @@
 #define DMA_TX_TYPE_END (DMA_INTERRUPT + 1)
 
 /**
+ * enum dma_prep_flags - DMA flags to augment operation preparation
+ * @DMA_PREP_INTERRUPT - trigger an interrupt (callback) upon completion of
+ * 	this transaction
+ */
+enum dma_prep_flags {
+	DMA_PREP_INTERRUPT = (1 << 0),
+};
+
+/**
  * dma_cap_mask_t - capabilities bitmap modeled after cpumask_t.
  * See linux/cpumask.h
  */
@@ -274,16 +283,16 @@
 
 	struct dma_async_tx_descriptor *(*device_prep_dma_memcpy)(
 		struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
-		size_t len, int int_en);
+		size_t len, unsigned long flags);
 	struct dma_async_tx_descriptor *(*device_prep_dma_xor)(
 		struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
-		unsigned int src_cnt, size_t len, int int_en);
+		unsigned int src_cnt, size_t len, unsigned long flags);
 	struct dma_async_tx_descriptor *(*device_prep_dma_zero_sum)(
 		struct dma_chan *chan, dma_addr_t *src,	unsigned int src_cnt,
-		size_t len, u32 *result, int int_en);
+		size_t len, u32 *result, unsigned long flags);
 	struct dma_async_tx_descriptor *(*device_prep_dma_memset)(
 		struct dma_chan *chan, dma_addr_t dest, int value, size_t len,
-		int int_en);
+		unsigned long flags);
 	struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)(
 		struct dma_chan *chan);