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Commit 759eb040 authored by Sonic Zhang's avatar Sonic Zhang Committed by Bryan Wu
Browse files

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



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: default avatarSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: default avatarBryan Wu <bryan.wu@analog.com>
parent c051489d

drivers/serial/bfin_5xx.c

+14 −48
Original line number Diff line number Diff line
@@ -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]);

	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)) {

	if ((UART_GET_IER(uart) & ETBEI) && (UART_GET_LSR(uart) & 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)

		bfin_serial_tx_chars(uart);

	spin_unlock(&uart->port.lock);

#endif



	return IRQ_HANDLED;

}