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Blackfin Serial driver: Fix bug - serial driver in PIO mode cant handle input very quickly

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Output as many bytes as possible in PIO tx handler.
This reduce the number of tx interrupts and shorten the delay to handle
rx interrupt. So, rx overrun disappears.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
This commit is contained in:
Sonic Zhang 2007-11-21 17:00:32 +08:00 committed by Bryan Wu
parent c051489df8
commit 759eb04090
1 changed files with 14 additions and 48 deletions
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62
drivers/serial/bfin_5xx.c
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@ -74,7 +74,6 @@ static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart);
#else
static void bfin_serial_do_work(struct work_struct *work);
static void bfin_serial_tx_chars(struct bfin_serial_port *uart);
static void local_put_char(struct bfin_serial_port *uart, char ch);
#endif
static void bfin_serial_mctrl_check(struct bfin_serial_port *uart);
@ -85,6 +84,9 @@ 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;
#ifndef CONFIG_BF54x
unsigned short ier;
#endif
while (!(UART_GET_LSR(uart) & TEMT))
continue;
@ -100,8 +102,6 @@ static void bfin_serial_stop_tx(struct uart_port *port)
UART_PUT_LSR(uart, TFI);
UART_CLEAR_IER(uart, ETBEI);
#else
unsigned short ier;
ier = UART_GET_IER(uart);
ier &= ~ETBEI;
UART_PUT_IER(uart, ier);
@ -210,23 +210,6 @@ int kgdb_get_debug_char(void)
#endif
#ifdef CONFIG_SERIAL_BFIN_PIO
static void local_put_char(struct bfin_serial_port *uart, char ch)
{
unsigned short status;
int flags = 0;
spin_lock_irqsave(&uart->port.lock, flags);
do {
status = UART_GET_LSR(uart);
} while (!(status & THRE));
UART_PUT_CHAR(uart, ch);
SSYNC();
spin_unlock_irqrestore(&uart->port.lock, flags);
}
static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
{
struct tty_struct *tty = uart->port.info->tty;
@ -236,8 +219,8 @@ static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
struct pt_regs *regs = get_irq_regs();
#endif
status = UART_GET_LSR(uart);
ch = UART_GET_CHAR(uart);
status = UART_GET_LSR(uart);
uart->port.icount.rx++;
#ifdef CONFIG_KGDB_UART
@ -337,9 +320,12 @@ static void bfin_serial_tx_chars(struct bfin_serial_port *uart)
return;
}
local_put_char(uart, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
uart->port.icount.tx++;
while ((UART_GET_LSR(uart) & THRE) && xmit->tail != xmit->head) {
UART_PUT_CHAR(uart, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
uart->port.icount.tx++;
SSYNC();
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&uart->port);
@ -352,21 +338,11 @@ static irqreturn_t bfin_serial_rx_int(int irq, void *dev_id)
{
struct bfin_serial_port *uart = dev_id;
#ifdef CONFIG_BF54x
unsigned short status;
spin_lock(&uart->port.lock);
status = UART_GET_LSR(uart);
while ((UART_GET_IER(uart) & ERBFI) && (status & DR)) {
bfin_serial_rx_chars(uart);
status = UART_GET_LSR(uart);
}
spin_unlock(&uart->port.lock);
#else
spin_lock(&uart->port.lock);
while ((UART_GET_IIR(uart) & IIR_STATUS) == IIR_RX_READY)
while ((UART_GET_IER(uart) & ERBFI) && (UART_GET_LSR(uart) & DR))
bfin_serial_rx_chars(uart);
spin_unlock(&uart->port.lock);
#endif
return IRQ_HANDLED;
}
@ -374,21 +350,11 @@ static irqreturn_t bfin_serial_tx_int(int irq, void *dev_id)
{
struct bfin_serial_port *uart = dev_id;
#ifdef CONFIG_BF54x
unsigned short status;
spin_lock(&uart->port.lock);
status = UART_GET_LSR(uart);
while ((UART_GET_IER(uart) & ETBEI) && (status & THRE)) {
bfin_serial_tx_chars(uart);
status = UART_GET_LSR(uart);
}
spin_unlock(&uart->port.lock);
#else
spin_lock(&uart->port.lock);
while ((UART_GET_IIR(uart) & IIR_STATUS) == IIR_TX_READY)
if ((UART_GET_IER(uart) & ETBEI) && (UART_GET_LSR(uart) & THRE))
bfin_serial_tx_chars(uart);
spin_unlock(&uart->port.lock);
#endif
return IRQ_HANDLED;
}