[Blackfin] serial driver: Fix bug serial driver in DMA mode spams history to console on shell restart
http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=2920
Fix by increasing buffer tail immediately before starting tx dma.
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index 838f491..0074146 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -411,6 +411,10 @@
set_dma_x_count(uart->tx_dma_channel, uart->tx_count);
set_dma_x_modify(uart->tx_dma_channel, 1);
enable_dma(uart->tx_dma_channel);
+
+ xmit->tail = (xmit->tail + uart->tx_count) & (UART_XMIT_SIZE - 1);
+ uart->port.icount.tx += uart->tx_count;
+
#ifdef CONFIG_BF54x
UART_SET_IER(uart, ETBEI);
#else
@@ -502,9 +506,6 @@
ier &= ~ETBEI;
UART_PUT_IER(uart, ier);
#endif
- xmit->tail = (xmit->tail+uart->tx_count) &(UART_XMIT_SIZE -1);
- uart->port.icount.tx+=uart->tx_count;
-
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&uart->port);