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

Browse source 
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
View file

@ -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;
}