fsldma: Fix the DMA halt when using DMA_INTERRUPT async_tx transfer.
The DMA_INTERRUPT async_tx is a NULL transfer, thus the BCR(count register)
is 0. When the transfer started with a byte count of zero, the DMA
controller will triger a PE(programming error) event and halt, not a normal
interrupt. I add special codes for PE event and DMA_INTERRUPT
async_tx testing.
Signed-off-by: Zhang Wei <wei.zhang@freescale.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index ad2f938..7269230 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -123,6 +123,11 @@
return DMA_IN(fsl_chan, &fsl_chan->reg_base->ndar, 64);
}
+static u32 get_bcr(struct fsl_dma_chan *fsl_chan)
+{
+ return DMA_IN(fsl_chan, &fsl_chan->reg_base->bcr, 32);
+}
+
static int dma_is_idle(struct fsl_dma_chan *fsl_chan)
{
u32 sr = get_sr(fsl_chan);
@@ -426,6 +431,9 @@
new->async_tx.cookie = -EBUSY;
new->async_tx.ack = 0;
+ /* Insert the link descriptor to the LD ring */
+ list_add_tail(&new->node, &new->async_tx.tx_list);
+
/* Set End-of-link to the last link descriptor of new list*/
set_ld_eol(fsl_chan, new);
@@ -701,6 +709,23 @@
if (stat & FSL_DMA_SR_TE)
dev_err(fsl_chan->dev, "Transfer Error!\n");
+ /* Programming Error
+ * The DMA_INTERRUPT async_tx is a NULL transfer, which will
+ * triger a PE interrupt.
+ */
+ if (stat & FSL_DMA_SR_PE) {
+ dev_dbg(fsl_chan->dev, "event: Programming Error INT\n");
+ if (get_bcr(fsl_chan) == 0) {
+ /* BCR register is 0, this is a DMA_INTERRUPT async_tx.
+ * Now, update the completed cookie, and continue the
+ * next uncompleted transfer.
+ */
+ fsl_dma_update_completed_cookie(fsl_chan);
+ fsl_chan_xfer_ld_queue(fsl_chan);
+ }
+ stat &= ~FSL_DMA_SR_PE;
+ }
+
/* If the link descriptor segment transfer finishes,
* we will recycle the used descriptor.
*/
@@ -841,6 +866,11 @@
tx3 = fsl_dma_prep_memcpy(chan, dma_dest, dma_src, test_size / 4, 0);
async_tx_ack(tx3);
+ /* Interrupt tx test */
+ tx1 = fsl_dma_prep_interrupt(chan);
+ async_tx_ack(tx1);
+ cookie = fsl_dma_tx_submit(tx1);
+
/* Test exchanging the prepared tx sort */
cookie = fsl_dma_tx_submit(tx3);
cookie = fsl_dma_tx_submit(tx2);