C++ serial_in函数代码示例

int omap_uart_active(int num, u32 timeout)
{
	struct uart_omap_port *up = ui[num];
	struct circ_buf *xmit;
	unsigned int status;

	/* Though when UART's initialised this can never happen,
	 * but during initialisation, it can happen the "ui"
	 * structure is not initialized and the timer kicks
	 * in. This would result in a NULL value, resulting
	 * in crash.
	 */
	if (up == NULL)
		return 0;

	/* Check for recent driver activity. If time delta from now
	 * to last activty < "uart idle timeout" second keep clocks on.
	 */
	if (((jiffies - up->port_activity) < timeout))
		return 1;

	xmit = &up->port.state->xmit;
	if (!(uart_circ_empty(xmit) || uart_tx_stopped(&up->port)))
		return 1;

	status = serial_in(up, UART_LSR);
	/* TX hardware not empty */
	if (!(status & (UART_LSR_TEMT | UART_LSR_THRE)))
		return 1;

	/* Any rx activity? */
	if (status & UART_LSR_DR)
		return 1;

	/* Check if DMA channels are active */
	if (up->use_dma && (up->uart_dma.rx_dma_channel != OMAP_UART_DMA_CH_FREE ||
		up->uart_dma.tx_dma_channel != OMAP_UART_DMA_CH_FREE))
		return 1;

	return 0;
}

/*
 * Print a string to the serial port trying not to disturb
 * any possible real use of the port...
 *
 *	The console_lock must be held when we get here.
 */
static void
serial_pxa_console_write(struct console *co, const char *s, unsigned int count)
{
	struct uart_pxa_port *up = &serial_pxa_ports[co->index];
	unsigned int ier;

	/*
	 *	First save the IER then disable the interrupts
	 */
	ier = serial_in(up, UART_IER);
	serial_out(up, UART_IER, UART_IER_UUE);

	uart_console_write(&up->port, s, count, serial_pxa_console_putchar);

	/*
	 *	Finally, wait for transmitter to become empty
	 *	and restore the IER
	 */
	wait_for_xmitr(up);
	serial_out(up, UART_IER, ier);
}

static void serial_omap_rdi(struct uart_omap_port *up, unsigned int lsr)
{
	unsigned char ch = 0;
	unsigned int flag;

	if (!(lsr & UART_LSR_DR))
		return;

	ch = serial_in(up, UART_RX);
	flag = TTY_NORMAL;
	up->port.icount.rx++;

#ifdef CONFIG_CONSOLE_POLL
	if (up->port.poll_rx_cb && up->port.poll_rx_cb(ch))
		return;
#endif
	if (uart_handle_sysrq_char(&up->port, ch))
		return;

	uart_insert_char(&up->port, lsr, UART_LSR_OE, ch, flag);
}

static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	struct uart_8250_port *up = up_to_u8250p(port);
	struct omap8250_priv *priv = up->port.private_data;
	u8 lcr;

	serial8250_do_set_mctrl(port, mctrl);

	/*
	 * Turn off autoRTS if RTS is lowered and restore autoRTS setting
	 * if RTS is raised
	 */
	lcr = serial_in(up, UART_LCR);
	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
	if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
		priv->efr |= UART_EFR_RTS;
	else
		priv->efr &= ~UART_EFR_RTS;
	serial_out(up, UART_EFR, priv->efr);
	serial_out(up, UART_LCR, lcr);
}

static void
serial_omap_pm(struct uart_port *port, unsigned int state,
	       unsigned int oldstate)
{
	struct uart_omap_port *up = (struct uart_omap_port *)port;
	unsigned char efr;

	dev_dbg(up->port.dev, "serial_omap_pm+%d\n", up->pdev->id);
	serial_out(up, UART_LCR, OMAP_UART_LCR_CONF_MDB);
	efr = serial_in(up, UART_EFR);
	serial_out(up, UART_EFR, efr | UART_EFR_ECB);
	serial_out(up, UART_LCR, 0);

	serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0);
	serial_out(up, UART_LCR, OMAP_UART_LCR_CONF_MDB);
	serial_out(up, UART_EFR, efr);
	serial_out(up, UART_LCR, 0);
	/* Enable module level wake up */
	serial_out(up, UART_OMAP_WER,
		(state != 0) ? OMAP_UART_WER_MOD_WKUP : 0);
}

static void ip3106_tx_chars(struct ip3106_port *sport)
{
	struct circ_buf *xmit = &sport->port.info->xmit;

	if (sport->port.x_char) {
		serial_out(sport, IP3106_FIFO, sport->port.x_char);
		sport->port.icount.tx++;
		sport->port.x_char = 0;
		return;
	}

	/*
	 * Check the modem control lines before
	 * transmitting anything.
	 */
	ip3106_mctrl_check(sport);

	if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
		ip3106_stop_tx(&sport->port, 0);
		return;
	}

	/*
	 * TX while bytes available
	 */
	while (((serial_in(sport, IP3106_FIFO) &
					IP3106_UART_FIFO_TXFIFO) >> 16) < 16) {
		serial_out(sport, IP3106_FIFO, xmit->buf[xmit->tail]);
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		sport->port.icount.tx++;
		if (uart_circ_empty(xmit))
			break;
	}

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

	if (uart_circ_empty(xmit))
		ip3106_stop_tx(&sport->port, 0);
}

static unsigned int serial_pxa_tx_empty(struct uart_port *port)
{
	struct uart_pxa_port *up = (struct uart_pxa_port *)port;
	unsigned long flags;
	unsigned int ret;

	spin_lock_irqsave(&up->port.lock, flags);

	if (up->dma_enable) {
		if (up->ier & UART_IER_DMAE) {
			if (up->uart_dma.dma_status & TX_DMA_RUNNING) {
				spin_unlock_irqrestore(&up->port.lock, flags);
				return 0;
			}
		}
	}

	ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
	spin_unlock_irqrestore(&up->port.lock, flags);

	return ret;
}

static unsigned int serial8250_get_mctrl(struct uart_port *port)
{
	struct uart_8250_port *up = (struct uart_8250_port *)port;
	unsigned long flags;
	unsigned char status;
	unsigned int ret;

	spin_lock_irqsave(&up->port.lock, flags);
	status = serial_in(up, UART_MSR);
	spin_unlock_irqrestore(&up->port.lock, flags);

	ret = 0;
	if (status & UART_MSR_DCD)
		ret |= TIOCM_CAR;
	if (status & UART_MSR_RI)
		ret |= TIOCM_RNG;
	if (status & UART_MSR_DSR)
		ret |= TIOCM_DSR;
	if (status & UART_MSR_CTS)
		ret |= TIOCM_CTS;
	return ret;
}

static inline void check_modem_status(struct uart_hsu_port *up)
{
	int status;

	status = serial_in(up, UART_MSR);

	if ((status & UART_MSR_ANY_DELTA) == 0)
		return;

	if (status & UART_MSR_TERI)
		up->port.icount.rng++;
	if (status & UART_MSR_DDSR)
		up->port.icount.dsr++;
	/* We may only get DDCD when HW init and reset */
	if (status & UART_MSR_DDCD)
		uart_handle_dcd_change(&up->port, status & UART_MSR_DCD);
	/* Will start/stop_tx accordingly */
	if (status & UART_MSR_DCTS)
		uart_handle_cts_change(&up->port, status & UART_MSR_CTS);

	wake_up_interruptible(&up->port.state->port.delta_msr_wait);
}

/*
 * Print a string to the serial port trying not to disturb
 * any possible real use of the port...
 *
 *	The console_lock must be held when we get here.
 */
static void
serial_pxa_console_write(struct console *co, const char *s, unsigned int count)
{
	struct uart_pxa_port *up = serial_pxa_ports[co->index];
	unsigned int ier;
	unsigned long flags;
	int locked = 1;

	clk_enable(up->clk);
	local_irq_save(flags);
	if (up->port.sysrq)
		locked = 0;
	else if (oops_in_progress)
		locked = spin_trylock(&up->port.lock);
	else
		spin_lock(&up->port.lock);

	/*
	 *	First save the IER then disable the interrupts
	 */
	ier = serial_in(up, UART_IER);
	serial_out(up, UART_IER, UART_IER_UUE);

	uart_console_write(&up->port, s, count, serial_pxa_console_putchar);

	/*
	 *	Finally, wait for transmitter to become empty
	 *	and restore the IER
	 */
	wait_for_xmitr(up);
	serial_out(up, UART_IER, ier);

	if (locked)
		spin_unlock(&up->port.lock);
	local_irq_restore(flags);
	clk_disable(up->clk);

}

//static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	struct uart_omap_port *up = (struct uart_omap_port *)port;
	unsigned char mcr = 0;

	dev_dbg(up->port.dev, "serial_omap_set_mctrl+%d\n", up->pdev->id);
	if (mctrl & TIOCM_RTS)
		mcr |= UART_MCR_RTS;
	if (mctrl & TIOCM_DTR)
		mcr |= UART_MCR_DTR;
	if (mctrl & TIOCM_OUT1)
		mcr |= UART_MCR_OUT1;
	if (mctrl & TIOCM_OUT2)
		mcr |= UART_MCR_OUT2;
	if (mctrl & TIOCM_LOOP)
		mcr |= UART_MCR_LOOP;

	serial_omap_port_enable(up);
	up->mcr = serial_in(up, UART_MCR);
	up->mcr |= mcr;
	serial_out(up, UART_MCR, up->mcr);
	serial_omap_port_disable(up);
}

static void
serial_omap_pm(struct uart_port *port, unsigned int state,
	       unsigned int oldstate)
{
	struct uart_omap_port *up = to_uart_omap_port(port);
	unsigned char efr;

	dev_dbg(up->port.dev, "serial_omap_pm+%d\n", up->port.line);

	pm_runtime_get_sync(up->dev);
	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
	efr = serial_in(up, UART_EFR);
	serial_out(up, UART_EFR, efr | UART_EFR_ECB);
	serial_out(up, UART_LCR, 0);

	serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0);
	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
	serial_out(up, UART_EFR, efr);
	serial_out(up, UART_LCR, 0);

	pm_runtime_mark_last_busy(up->dev);
	pm_runtime_put_autosuspend(up->dev);
}

static void serial_omap_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	struct uart_omap_port *up = (struct uart_omap_port *)port;
	unsigned char mcr = 0;

	dev_dbg(up->port.dev, "serial_omap_set_mctrl+%d\n", up->port.line);
	if (mctrl & TIOCM_RTS)
		mcr |= UART_MCR_RTS;
	if (mctrl & TIOCM_DTR)
		mcr |= UART_MCR_DTR;
	if (mctrl & TIOCM_OUT1)
		mcr |= UART_MCR_OUT1;
	if (mctrl & TIOCM_OUT2)
		mcr |= UART_MCR_OUT2;
	if (mctrl & TIOCM_LOOP)
		mcr |= UART_MCR_LOOP;

	pm_runtime_get_sync(&up->pdev->dev);
	up->mcr = serial_in(up, UART_MCR);
	up->mcr |= mcr;
	serial_out(up, UART_MCR, up->mcr);
	pm_runtime_put(&up->pdev->dev);
}

/*
 *	Print a string to the serial port trying not to disturb
 *	any possible real use of the port...
 *
 *	The console_lock must be held when we get here.
 */
static void
serial8250_console_write(struct console *co, const char *s, unsigned int count)
{
	struct uart_8250_port *up = &serial8250_ports[co->index];
	unsigned int ier;
	int i;

	/*
	 *	First save the UER then disable the interrupts
	 */
	ier = serial_in(up, UART_IER);
	serial_out(up, UART_IER, 0);

	/*
	 *	Now, do each character
	 */
	for (i = 0; i < count; i++, s++) {
		wait_for_xmitr(up);

		/*
		 *	Send the character out.
		 *	If a LF, also do CR...
		 */
		serial_out(up, UART_TX, *s);
		if (*s == 10) {
			wait_for_xmitr(up);
			serial_out(up, UART_TX, 13);
		}
	}

	/*
	 *	Finally, wait for transmitter to become empty
	 *	and restore the IER
	 */
	wait_for_xmitr(up);
	serial_out(up, UART_IER, ier);
}

static void transmit_chars(struct uart_sio_port *up)
{
	struct circ_buf *xmit = &up->port.state->xmit;
	int count;

	if (up->port.x_char) {
#ifndef CONFIG_SERIAL_M32R_PLDSIO	/* XXX */
		serial_out(up, UART_TX, up->port.x_char);
#endif
		up->port.icount.tx++;
		up->port.x_char = 0;
		return;
	}
	if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
		m32r_sio_stop_tx(&up->port);
		return;
	}

	count = up->port.fifosize;
	do {
		serial_out(up, UART_TX, xmit->buf[xmit->tail]);
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		up->port.icount.tx++;
		if (uart_circ_empty(xmit))
			break;
		while (!(serial_in(up, UART_LSR) & UART_LSR_THRE));

	} while (--count > 0);

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

	pr_debug("THRE...\n");

	if (uart_circ_empty(xmit))
		m32r_sio_stop_tx(&up->port);
}