diff --git a/arch/blackfin/kernel/bfin_dma_5xx.c b/arch/blackfin/kernel/bfin_dma_5xx.c
index df4d2a5b8e30..fd5448d6107c 100644
--- a/arch/blackfin/kernel/bfin_dma_5xx.c
+++ b/arch/blackfin/kernel/bfin_dma_5xx.c
@@ -106,12 +106,15 @@ int request_dma(unsigned int channel, char *device_id)
 
 #ifdef CONFIG_BF54x
 	if (channel >= CH_UART2_RX && channel <= CH_UART3_TX) {
-		if (strncmp(device_id, "BFIN_UART", 9) == 0)
+		if (strncmp(device_id, "BFIN_UART", 9) == 0) {
+			dma_ch[channel].regs->peripheral_map &= 0x0FFF;
 			dma_ch[channel].regs->peripheral_map |=
 				((channel - CH_UART2_RX + 0xC)<<12);
-		else
+		} else {
+			dma_ch[channel].regs->peripheral_map &= 0x0FFF;
 			dma_ch[channel].regs->peripheral_map |=
 				((channel - CH_UART2_RX + 0x6)<<12);
+		}
 	}
 #endif