C++ write_sbdchn函数代码示例

static void sbd_console_write(struct console *co, const char *s,
			      unsigned int count)
{
	int chip = co->index / DUART_MAX_SIDE;
	int side = co->index % DUART_MAX_SIDE;
	struct sbd_port *sport = &sbd_duarts[chip].sport[side];
	struct uart_port *uport = &sport->port;
	unsigned long flags;
	unsigned int mask;

	/* Disable transmit interrupts and enable the transmitter. */
	spin_lock_irqsave(&uport->lock, flags);
	mask = read_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2));
	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2),
		     mask & ~M_DUART_IMR_TX);
	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_EN);
	spin_unlock_irqrestore(&uport->lock, flags);

	uart_console_write(&sport->port, s, count, sbd_console_putchar);

	/* Restore transmit interrupts and the transmitter enable. */
	spin_lock_irqsave(&uport->lock, flags);
	sbd_line_drain(sport);
	if (sport->tx_stopped)
		write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS);
	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), mask);
	spin_unlock_irqrestore(&uport->lock, flags);
}

static int sbd_startup(struct uart_port *uport)
{
	struct sbd_port *sport = to_sport(uport);
	unsigned int mode1;
	int ret;

	ret = request_irq(sport->port.irq, sbd_interrupt,
			  IRQF_SHARED, "sb1250-duart", sport);
	if (ret)
		return ret;

	/* Clear the receive FIFO.  */
	sbd_receive_drain(sport);

	/* Clear the interrupt registers.  */
	write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_BREAK_INT);
	read_sbdshr(sport, R_DUART_INCHREG((uport->line) % 2));

	/* Set rx/tx interrupt to FIFO available.  */
	mode1 = read_sbdchn(sport, R_DUART_MODE_REG_1);
	mode1 &= ~(M_DUART_RX_IRQ_SEL_RXFULL | M_DUART_TX_IRQ_SEL_TXEMPT);
	write_sbdchn(sport, R_DUART_MODE_REG_1, mode1);

	/* Disable tx, enable rx.  */
	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS | M_DUART_RX_EN);
	sport->tx_stopped = 1;

	/* Enable interrupts.  */
	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2),
		     M_DUART_IMR_IN | M_DUART_IMR_RX);

	return 0;
}

static void sbd_break_ctl(struct uart_port *uport, int break_state)
{
	struct sbd_port *sport = to_sport(uport);

	if (break_state == -1)
		write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_START_BREAK);
	else
		write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_STOP_BREAK);
}

/*
 * Serial console stuff.  Very basic, polling driver for doing serial
 * console output.  The console_lock is held by the caller, so we
 * shouldn't be interrupted for more console activity.
 */
static void sbd_console_putchar(struct uart_port *uport, int ch)
{
	struct sbd_port *sport = to_sport(uport);

	sbd_transmit_drain(sport);
	write_sbdchn(sport, R_DUART_TX_HOLD, ch);
}

static void sbd_enable_ms(struct uart_port *uport)
{
	struct sbd_port *sport = to_sport(uport);

	write_sbdchn(sport, R_DUART_AUXCTL_X,
		     M_DUART_CIN_CHNG_ENA | M_DUART_CTS_CHNG_ENA);
}

static void sbd_stop_tx(struct uart_port *uport)
{
	struct sbd_port *sport = to_sport(uport);

	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS);
	sport->tx_stopped = 1;
};

static void sbd_set_mctrl(struct uart_port *uport, unsigned int mctrl)
{
	struct sbd_port *sport = to_sport(uport);
	unsigned int clr = 0, set = 0, mode2;

	if (mctrl & TIOCM_DTR)
		set |= M_DUART_SET_OPR2;
	else
		clr |= M_DUART_CLR_OPR2;
	if (mctrl & TIOCM_RTS)
		set |= M_DUART_SET_OPR0;
	else
		clr |= M_DUART_CLR_OPR0;
	clr <<= (uport->line) % 2;
	set <<= (uport->line) % 2;

	mode2 = read_sbdchn(sport, R_DUART_MODE_REG_2);
	mode2 &= ~M_DUART_CHAN_MODE;
	if (mctrl & TIOCM_LOOP)
		mode2 |= V_DUART_CHAN_MODE_LCL_LOOP;
	else
		mode2 |= V_DUART_CHAN_MODE_NORMAL;

	write_sbdshr(sport, R_DUART_CLEAR_OPR, clr);
	write_sbdshr(sport, R_DUART_SET_OPR, set);
	write_sbdchn(sport, R_DUART_MODE_REG_2, mode2);
}

static void sbd_shutdown(struct uart_port *uport)
{
	struct sbd_port *sport = to_sport(uport);

	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS | M_DUART_RX_DIS);
	sport->tx_stopped = 1;
	free_irq(sport->port.irq, sport);
}

static void sbd_start_tx(struct uart_port *uport)
{
	struct sbd_port *sport = to_sport(uport);
	unsigned int mask;

	/* Enable tx interrupts.  */
	mask = read_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2));
	mask |= M_DUART_IMR_TX;
	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), mask);

	/* Go!, go!, go!...  */
	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_EN);
	sport->tx_stopped = 0;
};

static void sbd_transmit_chars(struct sbd_port *sport)
{
	struct uart_port *uport = &sport->port;
	struct circ_buf *xmit = &sport->port.state->xmit;
	unsigned int mask;
	int stop_tx;

	/* XON/XOFF chars.  */
	if (sport->port.x_char) {
		write_sbdchn(sport, R_DUART_TX_HOLD, sport->port.x_char);
		sport->port.icount.tx++;
		sport->port.x_char = 0;
		return;
	}

	/* If nothing to do or stopped or hardware stopped.  */
	stop_tx = (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port));

	/* Send char.  */
	if (!stop_tx) {
		write_sbdchn(sport, R_DUART_TX_HOLD, xmit->buf[xmit->tail]);
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		sport->port.icount.tx++;

		if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
			uart_write_wakeup(&sport->port);
	}

	/* Are we are done?  */
	if (stop_tx || uart_circ_empty(xmit)) {
		/* Disable tx interrupts.  */
		mask = read_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2));
		mask &= ~M_DUART_IMR_TX;
		write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), mask);
	}
}

static void sbd_init_port(struct sbd_port *sport)
{
	struct uart_port *uport = &sport->port;

	if (sport->initialised)
		return;

	/* There is no DUART reset feature, so just set some sane defaults.  */
	write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_TX);
	write_sbdchn(sport, R_DUART_CMD, V_DUART_MISC_CMD_RESET_RX);
	write_sbdchn(sport, R_DUART_MODE_REG_1, V_DUART_BITS_PER_CHAR_8);
	write_sbdchn(sport, R_DUART_MODE_REG_2, 0);
	write_sbdchn(sport, R_DUART_FULL_CTL,
		     V_DUART_INT_TIME(0) | V_DUART_SIG_FULL(15));
	write_sbdchn(sport, R_DUART_OPCR_X, 0);
	write_sbdchn(sport, R_DUART_AUXCTL_X, 0);
	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), 0);

	sport->initialised = 1;
}

static void sbd_set_termios(struct uart_port *uport, struct ktermios *termios,
			    struct ktermios *old_termios)
{
	struct sbd_port *sport = to_sport(uport);
	unsigned int mode1 = 0, mode2 = 0, aux = 0;
	unsigned int mode1mask = 0, mode2mask = 0, auxmask = 0;
	unsigned int oldmode1, oldmode2, oldaux;
	unsigned int baud, brg;
	unsigned int command;

	mode1mask |= ~(M_DUART_PARITY_MODE | M_DUART_PARITY_TYPE_ODD |
		       M_DUART_BITS_PER_CHAR);
	mode2mask |= ~M_DUART_STOP_BIT_LEN_2;
	auxmask |= ~M_DUART_CTS_CHNG_ENA;

	/* Byte size.  */
	switch (termios->c_cflag & CSIZE) {
	case CS5:
	case CS6:
		/* Unsupported, leave unchanged.  */
		mode1mask |= M_DUART_PARITY_MODE;
		break;
	case CS7:
		mode1 |= V_DUART_BITS_PER_CHAR_7;
		break;
	case CS8:
	default:
		mode1 |= V_DUART_BITS_PER_CHAR_8;
		break;
	}

	/* Parity and stop bits.  */
	if (termios->c_cflag & CSTOPB)
		mode2 |= M_DUART_STOP_BIT_LEN_2;
	else
		mode2 |= M_DUART_STOP_BIT_LEN_1;
	if (termios->c_cflag & PARENB)
		mode1 |= V_DUART_PARITY_MODE_ADD;
	else
		mode1 |= V_DUART_PARITY_MODE_NONE;
	if (termios->c_cflag & PARODD)
		mode1 |= M_DUART_PARITY_TYPE_ODD;
	else
		mode1 |= M_DUART_PARITY_TYPE_EVEN;

	baud = uart_get_baud_rate(uport, termios, old_termios, 1200, 5000000);
	brg = V_DUART_BAUD_RATE(baud);
	/* The actual lower bound is 1221bps, so compensate.  */
	if (brg > M_DUART_CLK_COUNTER)
		brg = M_DUART_CLK_COUNTER;

	uart_update_timeout(uport, termios->c_cflag, baud);

	uport->read_status_mask = M_DUART_OVRUN_ERR;
	if (termios->c_iflag & INPCK)
		uport->read_status_mask |= M_DUART_FRM_ERR |
					   M_DUART_PARITY_ERR;
	if (termios->c_iflag & (BRKINT | PARMRK))
		uport->read_status_mask |= M_DUART_RCVD_BRK;

	uport->ignore_status_mask = 0;
	if (termios->c_iflag & IGNPAR)
		uport->ignore_status_mask |= M_DUART_FRM_ERR |
					     M_DUART_PARITY_ERR;
	if (termios->c_iflag & IGNBRK) {
		uport->ignore_status_mask |= M_DUART_RCVD_BRK;
		if (termios->c_iflag & IGNPAR)
			uport->ignore_status_mask |= M_DUART_OVRUN_ERR;
	}

	if (termios->c_cflag & CREAD)
		command = M_DUART_RX_EN;
	else
		command = M_DUART_RX_DIS;

	if (termios->c_cflag & CRTSCTS)
		aux |= M_DUART_CTS_CHNG_ENA;
	else
		aux &= ~M_DUART_CTS_CHNG_ENA;

	spin_lock(&uport->lock);

	if (sport->tx_stopped)
		command |= M_DUART_TX_DIS;
	else
		command |= M_DUART_TX_EN;

	oldmode1 = read_sbdchn(sport, R_DUART_MODE_REG_1) & mode1mask;
	oldmode2 = read_sbdchn(sport, R_DUART_MODE_REG_2) & mode2mask;
	oldaux = read_sbdchn(sport, R_DUART_AUXCTL_X) & auxmask;

	if (!sport->tx_stopped)
		sbd_line_drain(sport);
	write_sbdchn(sport, R_DUART_CMD, M_DUART_TX_DIS | M_DUART_RX_DIS);

	write_sbdchn(sport, R_DUART_MODE_REG_1, mode1 | oldmode1);
	write_sbdchn(sport, R_DUART_MODE_REG_2, mode2 | oldmode2);
	write_sbdchn(sport, R_DUART_CLK_SEL, brg);
	write_sbdchn(sport, R_DUART_AUXCTL_X, aux | oldaux);

//.........这里部分代码省略.........