dmaengine: at_hdmac: modify way to use interrupts

Now we use Buffer Transfer Completed interrupts. If we
want a chained buffer completed information, we setup the
ATC_IEN bit in CTRLB register in the lli.
This is done by set_desc_eol() function and used by
memcpy/slave_sg functions.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/drivers/dma/at_hdmac_regs.h b/drivers/dma/at_hdmac_regs.h
index 495457e..8303306 100644
--- a/drivers/dma/at_hdmac_regs.h
+++ b/drivers/dma/at_hdmac_regs.h
@@ -309,8 +309,8 @@
 	struct at_dma	*atdma = to_at_dma(atchan->chan_common.device);
 	u32		ebci;
 
-	/* enable interrupts on buffer chain completion & error */
-	ebci =    AT_DMA_CBTC(atchan->chan_common.chan_id)
+	/* enable interrupts on buffer transfer completion & error */
+	ebci =    AT_DMA_BTC(atchan->chan_common.chan_id)
 		| AT_DMA_ERR(atchan->chan_common.chan_id);
 	if (on)
 		dma_writel(atdma, EBCIER, ebci);
@@ -347,7 +347,12 @@
  */
 static void set_desc_eol(struct at_desc *desc)
 {
-	desc->lli.ctrlb |= ATC_SRC_DSCR_DIS | ATC_DST_DSCR_DIS;
+	u32 ctrlb = desc->lli.ctrlb;
+
+	ctrlb &= ~ATC_IEN;
+	ctrlb |= ATC_SRC_DSCR_DIS | ATC_DST_DSCR_DIS;
+
+	desc->lli.ctrlb = ctrlb;
 	desc->lli.dscr = 0;
 }