自学教程：C++ to_sport函数代码示例

/* * 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 int sbd_map_port(struct uart_port *uport){	const char *err = KERN_ERR "sbd: Cannot map MMIO/n";	struct sbd_port *sport = to_sport(uport);	struct sbd_duart *duart = sport->duart;	if (!uport->membase)		uport->membase = ioremap_nocache(uport->mapbase,						 DUART_CHANREG_SPACING);	if (!uport->membase) {;		return -ENOMEM;	}	if (!sport->memctrl)		sport->memctrl = ioremap_nocache(duart->mapctrl,						 DUART_CHANREG_SPACING);	if (!sport->memctrl) {;		iounmap(uport->membase);		uport->membase = NULL;		return -ENOMEM;	}	return 0;}

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_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_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);}

static void sbd_config_port(struct uart_port *uport, int flags){	struct sbd_port *sport = to_sport(uport);	if (flags & UART_CONFIG_TYPE) {		if (sbd_request_port(uport))			return;		uport->type = PORT_SB1250_DUART;		sbd_init_port(sport);	}}

static unsigned int sbd_get_mctrl(struct uart_port *uport){	struct sbd_port *sport = to_sport(uport);	unsigned int mctrl, status;	status = read_sbdshr(sport, R_DUART_IN_PORT);	status >>= (uport->line) % 2;	mctrl = (!(status & M_DUART_IN_PIN0_VAL) ? TIOCM_CTS : 0) |		(!(status & M_DUART_IN_PIN4_VAL) ? TIOCM_CAR : 0) |		(!(status & M_DUART_RIN0_PIN) ? TIOCM_RNG : 0) |		(!(status & M_DUART_IN_PIN2_VAL) ? TIOCM_DSR : 0);	return mctrl;}

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_release_port(struct uart_port *uport){	struct sbd_port *sport = to_sport(uport);	struct sbd_duart *duart = sport->duart;	int map_guard;	iounmap(sport->memctrl);	sport->memctrl = NULL;	iounmap(uport->membase);	uport->membase = NULL;	map_guard = atomic_add_return(-1, &duart->map_guard);	if (!map_guard)		release_mem_region(duart->mapctrl, DUART_CHANREG_SPACING);	release_mem_region(uport->mapbase, DUART_CHANREG_SPACING);}

static int sbd_request_port(struct uart_port *uport){	const char *err = KERN_ERR "sbd: Unable to reserve MMIO resource/n";	struct sbd_duart *duart = to_sport(uport)->duart;	int map_guard;	int ret = 0;	if (!request_mem_region(uport->mapbase, DUART_CHANREG_SPACING,				"sb1250-duart")) {;		return -EBUSY;	}	map_guard = atomic_add_return(1, &duart->map_guard);	if (map_guard == 1) {		if (!request_mem_region(duart->mapctrl, DUART_CHANREG_SPACING,					"sb1250-duart")) {			atomic_add(-1, &duart->map_guard);;			ret = -EBUSY;		}	}	if (!ret) {		ret = sbd_map_port(uport);		if (ret) {			map_guard = atomic_add_return(-1, &duart->map_guard);			if (!map_guard)				release_mem_region(duart->mapctrl,						   DUART_CHANREG_SPACING);		}	}	if (ret) {		release_mem_region(uport->mapbase, DUART_CHANREG_SPACING);		return ret;	}	return 0;}

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.........

static unsigned int sbd_tx_empty(struct uart_port *uport){	struct sbd_port *sport = to_sport(uport);	return sbd_transmit_empty(sport) ? TIOCSER_TEMT : 0;}

static void sbd_stop_rx(struct uart_port *uport){	struct sbd_port *sport = to_sport(uport);	write_sbdshr(sport, R_DUART_IMRREG((uport->line) % 2), 0);};