C++ receive_chars函数代码示例

/*
 * This is the serial driver's generic interrupt routine
 */
irqreturn_t rs_interrupt(int irq, void *dev_id)
{
	struct m68k_serial *info = dev_id;
	struct tty_struct *tty = tty_port_tty_get(&info->tport);
	m68328_uart *uart;
	unsigned short rx;
	unsigned short tx;

	uart = &uart_addr[info->line];
	rx = uart->urx.w;

#ifdef USE_INTS
	tx = uart->utx.w;

	if (rx & URX_DATA_READY)
		receive_chars(info, rx);
	if (tx & UTX_TX_AVAIL)
		transmit_chars(info, tty);
#else
	receive_chars(info, rx);
#endif
	tty_kref_put(tty);

	return IRQ_HANDLED;
}

static void max3110_console_receive(struct uart_max3110 *max)
{
	int loop = 1, num, total = 0;
	u8 recv_buf[512], *pbuf;

	pbuf = recv_buf;
	do {
		num = max3110_read_multi(max, 8, pbuf);

		if (num) {
			loop = 10;
			pbuf += num;
			total += num;

			if (total >= 500) {
				receive_chars(max, recv_buf, total);
				pbuf = recv_buf;
				total = 0;
			}
		}
	} while (--loop);

	if (total)
		receive_chars(max, recv_buf, total);
}

/*
 * Drain the Rx FIFO, called by interrupt handler.
 */
static void handle_receive(struct tile_uart_port *tile_uart)
{
	struct tty_port *port = &tile_uart->uart.state->port;
	struct tty_struct *tty = tty_port_tty_get(port);
	gxio_uart_context_t *context = &tile_uart->context;

	if (!tty)
		return;

	/* First read UART rx fifo. */
	receive_chars(tile_uart, tty);

	/* Reset RFIFO_WE interrupt. */
	gxio_uart_write(context, UART_INTERRUPT_STATUS,
			UART_INTERRUPT_MASK__RFIFO_WE_MASK);

	/* Final read, if any chars comes between the first read and
	 * the interrupt reset.
	 */
	receive_chars(tile_uart, tty);

	spin_unlock(&tile_uart->uart.lock);
	tty_flip_buffer_push(port);
	spin_lock(&tile_uart->uart.lock);
	tty_kref_put(tty);
}

/**
 * serial_omap_irq() - This handles the interrupt from one port
 * @irq: uart port irq number
 * @dev_id: uart port info
 */
static inline irqreturn_t serial_omap_irq(int irq, void *dev_id)
{
	struct uart_omap_port *up = dev_id;
	unsigned int iir, lsr;
	unsigned long flags;

	spin_lock_irqsave(&up->port.lock, flags);
#ifdef CONFIG_PM
	/*
	 * This will enable the clock for some reason if the
	 * clocks get disabled. This would enable the ICK also
	 * in case if the Idle state is set and the PRCM modul
	 * just shutdown the ICK because of inactivity.
	 */
	omap_uart_enable_clock_from_irq(up->pdev->id);
#endif

	iir = serial_in(up, UART_IIR);
	if (iir & UART_IIR_NO_INT) {
		spin_unlock_irqrestore(&up->port.lock, flags);
		return IRQ_NONE;
	}

	lsr = serial_in(up, UART_LSR);
	if (iir & UART_IIR_RLSI) {
		if (!up->use_dma) {
			if (lsr & UART_LSR_DR) {
				receive_chars(up, &lsr);
				if (omap_is_console_port(&up->port) &&
						(up->plat_hold_wakelock)) {
					spin_unlock(&up->port.lock);
					up->plat_hold_wakelock(up, WAKELK_IRQ);
					spin_lock(&up->port.lock);
				}
			}
		} else {
			up->ier &= ~UART_IER_RDI;
			serial_out(up, UART_IER, up->ier);
			if (serial_omap_start_rxdma(up) != 0)
				if (lsr & UART_LSR_DR)
					receive_chars(up, &lsr);
		}
	}

	check_modem_status(up);
	if ((lsr & UART_LSR_THRE) && (iir & UART_IIR_THRI))
		transmit_chars(up);

	spin_unlock_irqrestore(&up->port.lock, flags);
	up->port_activity = jiffies;
	return IRQ_HANDLED;
}

/**
 * serial_omap_irq() - This handles the interrupt from one port
 * @irq: uart port irq number
 * @dev_id: uart port info
 */
static inline irqreturn_t serial_omap_irq(int irq, void *dev_id)
{
	struct uart_omap_port *up = dev_id;
	unsigned int iir, lsr;
	unsigned int int_id;
	unsigned long flags;
	int ret = IRQ_HANDLED;
	u8 tx_fifo_lvl;

	serial_omap_port_enable(up);
	iir = serial_in(up, UART_IIR);
	if (iir & UART_IIR_NO_INT) {
		serial_omap_port_disable(up);
		return IRQ_NONE;
	}

	int_id = iir & UART_OMAP_IIR_ID;

	spin_lock_irqsave(&up->port.lock, flags);
	lsr = serial_in(up, UART_LSR);
	if (int_id == UART_IIR_RDI || int_id == UART_OMAP_IIR_RX_TIMEOUT ||
	    int_id == UART_IIR_RLSI) {
		if (!up->use_dma) {
			if (lsr & UART_LSR_DR)
				receive_chars(up, &lsr);
		} else {
			up->ier &= ~(UART_IER_RDI | UART_IER_RLSI);
			serial_out(up, UART_IER, up->ier);
			if ((serial_omap_start_rxdma(up) != 0) &&
					(lsr & UART_LSR_DR))
				receive_chars(up, &lsr);
		}
	}

	check_modem_status(up);
	if (int_id == UART_IIR_THRI) {
		tx_fifo_lvl = serial_in(up, UART_OMAP_TXFIFO_LVL);
		if (lsr & UART_LSR_THRE || tx_fifo_lvl < up->port.fifosize)
			transmit_chars(up, tx_fifo_lvl);
		else
			ret = IRQ_NONE;
	}

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

	up->port_activity = jiffies;
	return ret;
}

/* Write a 16b word to the device */
static int max3110_out(struct uart_max3110 *max, const u16 out)
{
	void *buf;
	u16 *obuf, *ibuf;
	u8  ch;
	int ret;

	buf = kzalloc(8, GFP_KERNEL | GFP_DMA);
	if (!buf)
		return -ENOMEM;

	obuf = buf;
	ibuf = buf + 4;
	*obuf = out;
	ret = max3110_write_then_read(max, obuf, ibuf, 2, 1);
	if (ret) {
		pr_warning(PR_FMT "%s(): get err msg %d when sending 0x%x\n",
				__func__, ret, out);
		goto exit;
	}

	/* If some valid data is read back */
	if (*ibuf & MAX3110_READ_DATA_AVAILABLE) {
		ch = *ibuf & 0xff;
		receive_chars(max, &ch, 1);
	}

exit:
	kfree(buf);
	return ret;
}

/*
 * This handles the interrupt from one port.
 */
static irqreturn_t
dpram_irq_rx(int irq, void *dev_id)
{
	dprintk("dpram_irq_rx\n");
	receive_chars(dev_id);
	return IRQ_HANDLED;
}

/*
 * This handles the interrupt from one port.
 */
static inline irqreturn_t serial_omap_irq(int irq, void *dev_id)
{
	struct uart_omap_port *up = dev_id;
	unsigned int iir, lsr;

	iir = serial_in(up, UART_IIR);
	if (iir & UART_IIR_NO_INT)
		return IRQ_NONE;
	lsr = serial_in(up, UART_LSR);
	if ((iir & 0x4) && up->use_dma) {
		up->ier &= ~UART_IER_RDI;
		serial_out(up, UART_IER, up->ier);
		serial_omap_start_rxdma(up);
	}
	else if (lsr & UART_LSR_DR) {
		receive_chars(up, &lsr);
	}
	check_modem_status(up);
	if ((lsr & UART_LSR_THRE) && (iir & 0x2)) {
		transmit_chars(up);
	}
	isr8250_activity = jiffies;

	return IRQ_HANDLED;
}

/* Write a 16b word to the device */
static int max3110_out(struct uart_max3110 *max, const u16 out)
{
	void *buf;
	u16 *obuf, *ibuf;
	int ret;

	buf = kzalloc(8, GFP_KERNEL | GFP_DMA);
	if (!buf)
		return -ENOMEM;

	obuf = buf;
	ibuf = buf + 4;
	*obuf = out;
	ret = max3110_write_then_read(max, obuf, ibuf, 2, 1);
	if (ret) {
		pr_warning(PR_FMT "%s(): get err msg %d when sending 0x%x\n",
				__func__, ret, out);
		goto exit;
	}

	receive_chars(max, ibuf, 1);

exit:
	kfree(buf);
	return ret;
}

/*
 * This is usually used to read data from SPIC RX FIFO, which doesn't
 * need any delay like flushing character out. It returns how many
 * valide bytes are read back
 */
static int max3110_read_multi(struct uart_max3110 *max, int len, u8 *buf)
{
	u16 out[MAX_READ_LEN], in[MAX_READ_LEN];
	u8 *pbuf, valid_str[MAX_READ_LEN];
	int i, j, bytelen;

	if (len > MAX_READ_LEN) {
		pr_err(PR_FMT "read len %d is too large\n", len);
		return 0;
	}

	bytelen = len * 2;
	memset(out, 0, bytelen);
	memset(in, 0, bytelen);

	if (max3110_write_then_read(max, (u8 *)out, (u8 *)in, bytelen, 1))
		return 0;

	/* If caller don't provide a buffer, then handle received char */
	pbuf = buf ? buf : valid_str;

	for (i = 0, j = 0; i < len; i++) {
		if (in[i] & MAX3110_READ_DATA_AVAILABLE)
			pbuf[j++] = (u8)(in[i] & 0xff);
	}

	if (j && (pbuf == valid_str))
		receive_chars(max, valid_str, j);

	return j;
}

/*
 * This is the serial driver's generic interrupt routine
 */
static irqreturn_t am_uart_interrupt(int irq, void *dev, struct pt_regs *regs)
{
    struct am_uart_port *info=(struct am_uart_port *)dev;
    am_uart_t *uart = NULL;
    struct tty_struct *tty = NULL;

    if (!info)
        goto out;

    tty = info->port.state->port.tty;
    if (!tty)
    {
        goto out;
    }

    uart = uart_addr[info->line];
    if (!uart)
        goto out;

    if (!(readl(&uart->status) & UART_RXEMPTY)){

        receive_chars(info, 0, readl(&uart->rdata));
    }

    if ((readl(&uart->mode) & UART_TXENB)&&!(readl(&uart->status) & UART_TXFULL)) {
        transmit_chars(info);
    }
out:
    am_uart_sched_event(info, 0);
    return IRQ_HANDLED;

}

static void rs_interrupt_elsa(struct IsdnCardState *cs)
{
	int status, iir, msr;
	int pass_counter = 0;
	
#ifdef SERIAL_DEBUG_INTR
;
#endif

	do {
		status = serial_inp(cs, UART_LSR);
		debugl1(cs,"rs LSR %02x", status);
#ifdef SERIAL_DEBUG_INTR
;
#endif
		if (status & UART_LSR_DR)
			receive_chars(cs, &status);
		if (status & UART_LSR_THRE)
			transmit_chars(cs, NULL);
		if (pass_counter++ > RS_ISR_PASS_LIMIT) {
;
			break;
		}
		iir = serial_inp(cs, UART_IIR);
		debugl1(cs,"rs IIR %02x", iir);
		if ((iir & 0xf) == 0) {
			msr = serial_inp(cs, UART_MSR);
			debugl1(cs,"rs MSR %02x", msr);
		}
	} while (!(iir & UART_IIR_NO_INT));
#ifdef SERIAL_DEBUG_INTR
;
#endif
}

static void sci_rx_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
	int ch;
	for(ch=0;ch<NR_PORTS;ch++)
		if(rs_table[ch].irq+1==irq)
			receive_chars(&rs_table[ch]);
}

/*
 * This is usually used to read data from SPIC RX FIFO, which doesn't
 * need any delay like flushing character out.
 *
 * Return how many valide bytes are read back
 */
static int max3110_read_multi(struct uart_max3110 *max)
{
	void *buf;
	u16 *obuf, *ibuf;
	int ret, blen;

	blen = M3110_RX_FIFO_DEPTH * sizeof(u16);
	buf = kzalloc(blen * 2, GFP_KERNEL | GFP_DMA);
	if (!buf) {
		pr_warning(PR_FMT "%s(): fail to alloc dma buffer\n", __func__);
		return 0;
	}

	/* tx/rx always have the same length */
	obuf = buf;
	ibuf = buf + blen;

	if (max3110_write_then_read(max, obuf, ibuf, blen, 1)) {
		kfree(buf);
		return 0;
	}

	ret = receive_chars(max, ibuf, M3110_RX_FIFO_DEPTH);

	kfree(buf);
	return ret;
}

void rs_interrupt(int irq, void * dev_id, struct pt_regs * regs)
{
	char status;

	struct cnxt_serial * info = &uart_info;
  	struct uart_regs *uart = uart_info.uart;
  	
	status = (uart->iir & 0x0f); /* only concerned w/ lower nibble */
	
	if (status == ISR_Tx_Rdy_Source) {
		transmit_chars(info);
	}
	if ((status == ISR_Rx_Rdy_Source) ||
            (status == ISR_Rx_Rdy_TO_Src )){
		receive_chars(info,status);
	}
	#if 0
		if(!info->use_ints){
			serialpoll.data = (void *)&sp_uart_info;		
			queue_task_irq_off(&serialpoll, &tq_timer);
		}
	#endif


	return;
}