[Blackfin] arch: fix bug - before assign new channel to the map register, need clear the bits first.

http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=2445

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

1 files changed, 5 insertions, 2 deletions

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