fsldma: Add device_prep_dma_interrupt support to fsldma.c

This is a bug that I assigned DMA_INTERRUPT capability to fsldma
but missing device_prep_dma_interrupt function. For a bug in
dmaengine.c the driver passed BUG_ON() checking. The patch fixes it.

Signed-off-by: Zhang Wei <wei.zhang@freescale.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index 5dfedf326573..cbd5b9684521 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -406,6 +406,32 @@ static void fsl_dma_free_chan_resources(struct dma_chan *chan)
         dma_pool_destroy(fsl_chan->desc_pool);
 }
 
+static struct dma_async_tx_descriptor *
+fsl_dma_prep_interrupt(struct dma_chan *chan)
+{
+        struct fsl_dma_chan *fsl_chan;
+        struct fsl_desc_sw *new;
+
+        if (!chan)
+                return NULL;
+
+        fsl_chan = to_fsl_chan(chan);
+
+        new = fsl_dma_alloc_descriptor(fsl_chan);
+        if (!new) {
+                dev_err(fsl_chan->dev, "No free memory for link descriptor\n");
+                return NULL;
+        }
+
+        new->async_tx.cookie = -EBUSY;
+        new->async_tx.ack = 0;
+
+        /* Set End-of-link to the last link descriptor of new list*/
+        set_ld_eol(fsl_chan, new);
+
+        return &new->async_tx;
+}
+
 static struct dma_async_tx_descriptor *fsl_dma_prep_memcpy(
         struct dma_chan *chan, dma_addr_t dma_dest, dma_addr_t dma_src,
         size_t len, unsigned long flags)
@@ -1020,6 +1046,7 @@ static int __devinit of_fsl_dma_probe(struct of_device *dev,
         dma_cap_set(DMA_INTERRUPT, fdev->common.cap_mask);
         fdev->common.device_alloc_chan_resources = fsl_dma_alloc_chan_resources;
         fdev->common.device_free_chan_resources = fsl_dma_free_chan_resources;
+        fdev->common.device_prep_dma_interrupt = fsl_dma_prep_interrupt;
         fdev->common.device_prep_dma_memcpy = fsl_dma_prep_memcpy;
         fdev->common.device_is_tx_complete = fsl_dma_is_complete;
         fdev->common.device_issue_pending = fsl_dma_memcpy_issue_pending;