irport.c

底层驱动开发

	if(count == 0)
		IRDA_DEBUG(0, "%s(): stuck transmitter\n", __FUNCTION__);
}

/*
 * Function irport_hard_start_xmit (struct sk_buff *skb, struct net_device *dev)
 *
 *    Transmits the current frame until FIFO is full, then
 *    waits until the next transmitt interrupt, and continues until the
 *    frame is transmitted.
 */
static int irport_hard_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct irport_cb *self;
	unsigned long flags;
	int iobase;
	s32 speed;

	IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(dev != NULL, return 0;);
	
	self = (struct irport_cb *) dev->priv;
	IRDA_ASSERT(self != NULL, return 0;);

	iobase = self->io.sir_base;

	netif_stop_queue(dev);

	/* Make sure tests & speed change are atomic */
	spin_lock_irqsave(&self->lock, flags);

	/* Check if we need to change the speed */
	speed = irda_get_next_speed(skb);
	if ((speed != self->io.speed) && (speed != -1)) {
		/* Check for empty frame */
		if (!skb->len) {
			/*
			 * We send frames one by one in SIR mode (no
			 * pipelining), so at this point, if we were sending
			 * a previous frame, we just received the interrupt
			 * telling us it is finished (UART_IIR_THRI).
			 * Therefore, waiting for the transmitter to really
			 * finish draining the fifo won't take too long.
			 * And the interrupt handler is not expected to run.
			 * - Jean II */
			irport_wait_hw_transmitter_finish(self);
			/* Better go there already locked - Jean II */
			irda_task_execute(self, __irport_change_speed, 
					  irport_change_speed_complete, 
					  NULL, (void *) speed);
			dev->trans_start = jiffies;
			spin_unlock_irqrestore(&self->lock, flags);
			dev_kfree_skb(skb);
			return 0;
		} else
			self->new_speed = speed;
	}

	/* Init tx buffer */
	self->tx_buff.data = self->tx_buff.head;

        /* Copy skb to tx_buff while wrapping, stuffing and making CRC */
	self->tx_buff.len = async_wrap_skb(skb, self->tx_buff.data, 
					   self->tx_buff.truesize);
	
	self->stats.tx_bytes += self->tx_buff.len;

	/* We are transmitting */
	self->transmitting = 1;

	/* Turn on transmit finished interrupt. Will fire immediately!  */
	outb(UART_IER_THRI, iobase+UART_IER); 

	dev->trans_start = jiffies;
	spin_unlock_irqrestore(&self->lock, flags);

	dev_kfree_skb(skb);
	
	return 0;
}
        
/*
 * Function irport_write (driver)
 *
 *    Fill Tx FIFO with transmit data
 *
 * Called only from irport_write_wakeup()
 */
static inline int irport_write(int iobase, int fifo_size, __u8 *buf, int len)
{
	int actual = 0;

	/* Fill FIFO with current frame */
	while ((actual < fifo_size) && (actual < len)) {
		/* Transmit next byte */
		outb(buf[actual], iobase+UART_TX);

		actual++;
	}
        
	return actual;
}

/*
 * Function irport_write_wakeup (tty)
 *
 *    Called by the driver when there's room for more data.  If we have
 *    more packets to send, we send them here.
 *
 * Called only from irport_interrupt()
 * Make sure this function is *not* called while we are receiving,
 * otherwise we will reset fifo and loose data :-(
 */
static inline void irport_write_wakeup(struct irport_cb *self)
{
	int actual = 0;
	int iobase;
	unsigned int fcr;

	IRDA_ASSERT(self != NULL, return;);

	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	iobase = self->io.sir_base;

	/* Finished with frame?  */
	if (self->tx_buff.len > 0)  {
		/* Write data left in transmit buffer */
		actual = irport_write(iobase, self->io.fifo_size, 
				      self->tx_buff.data, self->tx_buff.len);
		self->tx_buff.data += actual;
		self->tx_buff.len  -= actual;
	} else {
		/* 
		 *  Now serial buffer is almost free & we can start 
		 *  transmission of another packet. But first we must check
		 *  if we need to change the speed of the hardware
		 */
		if (self->new_speed) {
			irport_wait_hw_transmitter_finish(self);
			irda_task_execute(self, __irport_change_speed, 
					  irport_change_speed_complete, 
					  NULL, (void *) self->new_speed);
			self->new_speed = 0;
		} else {
			/* Tell network layer that we want more frames */
			netif_wake_queue(self->netdev);
		}
		self->stats.tx_packets++;

		/* 
		 * Reset Rx FIFO to make sure that all reflected transmit data
		 * is discarded. This is needed for half duplex operation
		 */
		fcr = irport_get_fcr(self->io.speed);
		fcr |= UART_FCR_CLEAR_RCVR;
		outb(fcr, iobase+UART_FCR);

		/* Finished transmitting */
		self->transmitting = 0;

		/* Turn on receive interrupts */
		outb(UART_IER_RDI, iobase+UART_IER);

		IRDA_DEBUG(1, "%s() : finished Tx\n", __FUNCTION__);
	}
}

/*
 * Function irport_receive (self)
 *
 *    Receive one frame from the infrared port
 *
 * Called only from irport_interrupt()
 */
static inline void irport_receive(struct irport_cb *self) 
{
	int boguscount = 0;
	int iobase;

	IRDA_ASSERT(self != NULL, return;);

	iobase = self->io.sir_base;

	/*  
	 * Receive all characters in Rx FIFO, unwrap and unstuff them. 
         * async_unwrap_char will deliver all found frames  
	 */
	do {
		async_unwrap_char(self->netdev, &self->stats, &self->rx_buff, 
				  inb(iobase+UART_RX));

		/* Make sure we don't stay here too long */
		if (boguscount++ > 32) {
			IRDA_DEBUG(2,"%s(), breaking!\n", __FUNCTION__);
			break;
		}
	} while (inb(iobase+UART_LSR) & UART_LSR_DR);	
}

/*
 * Function irport_interrupt (irq, dev_id, regs)
 *
 *    Interrupt handler
 */
static irqreturn_t irport_interrupt(int irq, void *dev_id,
				    struct pt_regs *regs) 
{
	struct net_device *dev = (struct net_device *) dev_id;
	struct irport_cb *self;
	int boguscount = 0;
	int iobase;
	int iir, lsr;
	int handled = 0;

	if (!dev) {
		IRDA_WARNING("%s() irq %d for unknown device.\n", __FUNCTION__, irq);
		return IRQ_NONE;
	}
	self = (struct irport_cb *) dev->priv;

	spin_lock(&self->lock);

	iobase = self->io.sir_base;

	/* Cut'n'paste interrupt routine from serial.c
	 * This version try to minimise latency and I/O operations.
	 * Simplified and modified to enforce half duplex operation.
	 * - Jean II */

	/* Check status even is iir reg is cleared, more robust and
	 * eliminate a read on the I/O bus - Jean II */
	do {
		/* Get interrupt status ; Clear interrupt */
		lsr = inb(iobase+UART_LSR);
		
		/* Are we receiving or transmitting ? */
		if(!self->transmitting) {
			/* Received something ? */
			if (lsr & UART_LSR_DR)
				irport_receive(self);
		} else {
			/* Room in Tx fifo ? */
			if (lsr & (UART_LSR_THRE | UART_LSR_TEMT))
				irport_write_wakeup(self);
		}

		/* A bit hackish, but working as expected... Jean II */
		if(lsr & (UART_LSR_THRE | UART_LSR_TEMT | UART_LSR_DR))
			handled = 1;

		/* Make sure we don't stay here to long */
		if (boguscount++ > 10) {
			IRDA_WARNING("%s() irq handler looping : lsr=%02x\n",
				     __FUNCTION__, lsr);
			break;
		}

		/* Read interrupt register */
 	        iir = inb(iobase+UART_IIR);

		/* Enable this debug only when no other options and at low
		 * bit rates, otherwise it may cause Rx overruns (lsr=63).
		 * - Jean II */
		IRDA_DEBUG(6, "%s(), iir=%02x, lsr=%02x, iobase=%#x\n", 
			    __FUNCTION__, iir, lsr, iobase);

		/* As long as interrupt pending... */
	} while ((iir & UART_IIR_NO_INT) == 0);

	spin_unlock(&self->lock);
	return IRQ_RETVAL(handled);
}

/*
 * Function irport_net_open (dev)
 *
 *    Network device is taken up. Usually this is done by "ifconfig irda0 up" 
 *   
 */
static int irport_net_open(struct net_device *dev)
{
	struct irport_cb *self;
	int iobase;
	char hwname[16];
	unsigned long flags;

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(dev != NULL, return -1;);
	self = (struct irport_cb *) dev->priv;

	iobase = self->io.sir_base;

	if (request_irq(self->io.irq, self->interrupt, 0, dev->name, 
			(void *) dev)) {
		IRDA_DEBUG(0, "%s(), unable to allocate irq=%d\n",
			   __FUNCTION__, self->io.irq);
		return -EAGAIN;
	}

	spin_lock_irqsave(&self->lock, flags);
	/* Init uart */
	irport_start(self);
	/* Set 9600 bauds per default, including at the dongle */
	irda_task_execute(self, __irport_change_speed, 
			  irport_change_speed_complete, 
			  NULL, (void *) 9600);
	spin_unlock_irqrestore(&self->lock, flags);


	/* Give self a hardware name */
	sprintf(hwname, "SIR @ 0x%03x", self->io.sir_base);

	/* 
	 * Open new IrLAP layer instance, now that everything should be
	 * initialized properly 
	 */
	self->irlap = irlap_open(dev, &self->qos, hwname);

	/* Ready to play! */

	netif_start_queue(dev);

	return 0;
}

/*
 * Function irport_net_close (self)
 *
 *    Network device is taken down. Usually this is done by 
 *    "ifconfig irda0 down" 
 */
static int irport_net_close(struct net_device *dev)
{
	struct irport_cb *self;
	int iobase;
	unsigned long flags;

	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(dev != NULL, return -1;);
	self = (struct irport_cb *) dev->priv;

	IRDA_ASSERT(self != NULL, return -1;);

	iobase = self->io.sir_base;

	/* Stop device */
	netif_stop_queue(dev);
	
	/* Stop and remove instance of IrLAP */
	if (self->irlap)
		irlap_close(self->irlap);
	self->irlap = NULL;

	spin_lock_irqsave(&self->lock, flags);
	irport_stop(self);
	spin_unlock_irqrestore(&self->lock, flags);

	free_irq(self->io.irq, dev);

	return 0;
}

/*
 * Function irport_is_receiving (self)
 *
 *    Returns true is we are currently receiving data
 *
 */
static inline int irport_is_receiving(struct irport_cb *self)
{
	return (self->rx_buff.state != OUTSIDE_FRAME);
}

/*
 * Function irport_set_dtr_rts (tty, dtr, rts)
 *
 *    This function can be used by dongles etc. to set or reset the status
 *    of the dtr and rts lines
 */
static int irport_set_dtr_rts(struct net_device *dev, int dtr, int rts)
{
	struct irport_cb *self = dev->priv;
	int iobase;

	IRDA_ASSERT(self != NULL, return -1;);

	iobase = self->io.sir_base;

	if (dtr)
		dtr = UART_MCR_DTR;
	if (rts)
		rts = UART_MCR_RTS;

	outb(dtr|rts|UART_MCR_OUT2, iobase+UART_MCR);

	return 0;
}

static int irport_raw_write(struct net_device *dev, __u8 *buf, int len)
{
	struct irport_cb *self = (struct irport_cb *) dev->priv;
	int actual = 0;
	int iobase;

	IRDA_ASSERT(self != NULL, return -1;);

	iobase = self->io.sir_base;

	/* Tx FIFO should be empty! */
	if (!(inb(iobase+UART_LSR) & UART_LSR_THRE)) {
		IRDA_DEBUG( 0, "%s(), failed, fifo not empty!\n", __FUNCTION__);
		return -1;
	}
        
	/* Fill FIFO with current frame */
	while (actual < len) {
		/* Transmit next byte */
		outb(buf[actual], iobase+UART_TX);
		actual++;
	}

	return actual;
}

/*
 * Function irport_net_ioctl (dev, rq, cmd)
 *
 *    Process IOCTL commands for this device
 *
 */
static int irport_net_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
	struct if_irda_req *irq = (struct if_irda_req *) rq;
	struct irport_cb *self;
	dongle_t *dongle;
	unsigned long flags;
	int ret = 0;

	IRDA_ASSERT(dev != NULL, return -1;);

	self = dev->priv;

	IRDA_ASSERT(self != NULL, return -1;);

	IRDA_DEBUG(2, "%s(), %s, (cmd=0x%X)\n", __FUNCTION__, dev->name, cmd);
	
	switch (cmd) {
	case SIOCSBANDWIDTH: /* Set bandwidth */
		if (!capable(CAP_NET_ADMIN))
			ret = -EPERM;
                else
			irda_task_execute(self, __irport_change_speed, NULL, 
					  NULL, (void *) irq->ifr_baudrate);
		break;
	case SIOCSDONGLE: /* Set dongle */
		if (!capable(CAP_NET_ADMIN)) {
			ret = -EPERM;
			break;
		}

		/* Locking :
		 * irda_device_dongle_init() can't be locked.
		 * irda_task_execute() doesn't need to be locked.
		 * Jean II
		 */

		/* Initialize dongle */
		dongle = irda_device_dongle_init(dev, irq->ifr_dongle);
		if (!dongle)
			break;
		
		dongle->set_mode    = NULL;
		dongle->read        = NULL;
		dongle->write       = irport_raw_write;
		dongle->set_dtr_rts = irport_set_dtr_rts;
		
		/* Now initialize the dongle!  */
		dongle->issue->open(dongle, &self->qos);
		
		/* Reset dongle */
		irda_task_execute(dongle, dongle->issue->reset, NULL, NULL, 
				  NULL);	

		/* Make dongle available to driver only now to avoid
		 * race conditions - Jean II */
		self->dongle = dongle;
		break;
	case SIOCSMEDIABUSY: /* Set media busy */
		if (!capable(CAP_NET_ADMIN)) {
			ret = -EPERM;
			break;
		}

		irda_device_set_media_busy(self->netdev, TRUE);
		break;
	case SIOCGRECEIVING: /* Check if we are receiving right now */
		irq->ifr_receiving = irport_is_receiving(self);
		break;
	case SIOCSDTRRTS:
		if (!capable(CAP_NET_ADMIN)) {
			ret = -EPERM;
			break;
		}

		/* No real need to lock... */
		spin_lock_irqsave(&self->lock, flags);
		irport_set_dtr_rts(dev, irq->ifr_dtr, irq->ifr_rts);
		spin_unlock_irqrestore(&self->lock, flags);
		break;
	default:
		ret = -EOPNOTSUPP;
	}
	
	return ret;
}

static struct net_device_stats *irport_net_get_stats(struct net_device *dev)
{
	struct irport_cb *self = (struct irport_cb *) dev->priv;
	
	return &self->stats;
}

static int __init irport_init(void)
{
 	int i;

 	for (i=0; (io[i] < 2000) && (i < 4); i++) {
 		if (irport_open(i, io[i], irq[i]) != NULL)
 			return 0;
 	}
	/* 
	 * Maybe something failed, but we can still be usable for FIR drivers 
	 */
 	return 0;
}

/*
 * Function irport_cleanup ()
 *
 *    Close all configured ports
 *
 */
static void __exit irport_cleanup(void)
{
 	int i;

        IRDA_DEBUG( 4, "%s()\n", __FUNCTION__);

	for (i=0; i < 4; i++) {
 		if (dev_self[i])
 			irport_close(dev_self[i]);
 	}
}

MODULE_PARM(io, "1-4i");
MODULE_PARM_DESC(io, "Base I/O addresses");
MODULE_PARM(irq, "1-4i");
MODULE_PARM_DESC(irq, "IRQ lines");

MODULE_AUTHOR("Dag Brattli <[e-mail]>");
MODULE_DESCRIPTION("Half duplex serial driver for IrDA SIR mode");
MODULE_LICENSE("GPL");

module_init(irport_init);
module_exit(irport_cleanup);