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Blackfin Serial Driver: Fix bug - Increase buffer tail immediately be…
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…fore 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>
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Sonic Zhang authored and Bryan Wu committed Feb 25, 2008
1 parent db28838 commit 0711d85
Showing 1 changed file with 18 additions and 14 deletions.
32 changes: 18 additions & 14 deletions drivers/serial/bfin_5xx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -64,15 +64,20 @@ static void bfin_serial_mctrl_check(struct bfin_serial_port *uart);
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 */
Expand All @@ -94,7 +99,8 @@ static void bfin_serial_start_tx(struct uart_port *port)
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);
Expand Down Expand Up @@ -389,12 +395,10 @@ static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart)
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;
}
Expand Down Expand Up @@ -428,9 +432,6 @@ static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart)
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
Expand Down Expand Up @@ -515,8 +516,8 @@ static irqreturn_t bfin_serial_dma_tx_int(int irq, void *dev_id)

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
Expand All @@ -527,7 +528,8 @@ static irqreturn_t bfin_serial_dma_tx_int(int irq, void *dev_id)
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);
}
Expand All @@ -542,12 +544,14 @@ static irqreturn_t bfin_serial_dma_rx_int(int irq, void *dev_id)
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);
Expand Down

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