Blackfin Serial Driver: Fix bug - Increase buffer tail immediately before starting tx dma.
http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=2920
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index 69ac700..2fb3081 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -64,15 +64,20 @@
static void bfin_serial_stop_tx(struct uart_port *port)
{
struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
+ struct circ_buf *xmit = &uart->port.info->xmit;
#if !defined(CONFIG_BF54x) && !defined(CONFIG_SERIAL_BFIN_DMA)
unsigned short ier;
#endif
while (!(UART_GET_LSR(uart) & TEMT))
- continue;
+ cpu_relax();
#ifdef CONFIG_SERIAL_BFIN_DMA
disable_dma(uart->tx_dma_channel);
+ xmit->tail = (xmit->tail + uart->tx_count) & (UART_XMIT_SIZE - 1);
+ uart->port.icount.tx += uart->tx_count;
+ uart->tx_count = 0;
+ uart->tx_done = 1;
#else
#ifdef CONFIG_BF54x
/* Clear TFI bit */
@@ -94,7 +99,8 @@
struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
#ifdef CONFIG_SERIAL_BFIN_DMA
- bfin_serial_dma_tx_chars(uart);
+ if (uart->tx_done)
+ bfin_serial_dma_tx_chars(uart);
#else
#ifdef CONFIG_BF54x
UART_SET_IER(uart, ETBEI);
@@ -389,12 +395,10 @@
unsigned short ier;
int flags = 0;
- if (!uart->tx_done)
- return;
uart->tx_done = 0;
if (uart_circ_empty(xmit) || uart_tx_stopped(&uart->port)) {
- bfin_serial_stop_tx(&uart->port);
+ uart->tx_count = 0;
uart->tx_done = 1;
return;
}
@@ -428,9 +432,6 @@
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
@@ -515,8 +516,8 @@
spin_lock(&uart->port.lock);
if (!(get_dma_curr_irqstat(uart->tx_dma_channel)&DMA_RUN)) {
- clear_dma_irqstat(uart->tx_dma_channel);
disable_dma(uart->tx_dma_channel);
+ clear_dma_irqstat(uart->tx_dma_channel);
#ifdef CONFIG_BF54x
UART_CLEAR_IER(uart, ETBEI);
#else
@@ -527,7 +528,8 @@
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&uart->port);
- uart->tx_done = 1;
+ xmit->tail = (xmit->tail + uart->tx_count) & (UART_XMIT_SIZE - 1);
+ uart->port.icount.tx += uart->tx_count;
bfin_serial_dma_tx_chars(uart);
}
@@ -542,12 +544,14 @@
unsigned short irqstat;
uart->rx_dma_nrows++;
- if (uart->rx_dma_nrows == DMA_RX_YCOUNT) {
+ uart->rx_dma_buf.tail = DMA_RX_XCOUNT * uart->rx_dma_nrows;
+ bfin_serial_dma_rx_chars(uart);
+ if (uart->rx_dma_nrows >= DMA_RX_YCOUNT) {
uart->rx_dma_nrows = 0;
- uart->rx_dma_buf.tail = DMA_RX_XCOUNT*DMA_RX_YCOUNT;
- bfin_serial_dma_rx_chars(uart);
- uart->rx_dma_buf.head = uart->rx_dma_buf.tail = 0;
+ uart->rx_dma_buf.tail = 0;
}
+ uart->rx_dma_buf.head = uart->rx_dma_buf.tail;
+
spin_lock(&uart->port.lock);
irqstat = get_dma_curr_irqstat(uart->rx_dma_channel);
clear_dma_irqstat(uart->rx_dma_channel);