stir4200.c

《linux驱动程序设计从入门到精通》一书中所有的程序代码含驱动和相应的应用程序

	if (unlikely(skb)) {
		WARN_ON(1);
		dev_kfree_skb(skb);
	}

	return 0;
}

/*
 * Wait for the transmit FIFO to have space for next data
 *
 * If space < 0 then wait till FIFO completely drains.
 * FYI: can take up to 13 seconds at 2400baud.
 */
static int fifo_txwait(struct stir_cb *stir, int space)
{
	int err;
	unsigned long count, status;

	/* Read FIFO status and count */
	for(;;) {
		err = read_reg(stir, REG_FIFOCTL, stir->fifo_status, 
				   FIFO_REGS_SIZE);
		if (unlikely(err != FIFO_REGS_SIZE)) {
			warn("%s: FIFO register read error: %d", 
			     stir->netdev->name, err);

			return err;
		}

		status = stir->fifo_status[0];
		count = (unsigned)(stir->fifo_status[2] & 0x1f) << 8 
			| stir->fifo_status[1];

		pr_debug("fifo status 0x%lx count %lu\n", status, count);

		/* is fifo receiving already, or empty */
		if (!(status & FIFOCTL_DIR)
		    || (status & FIFOCTL_EMPTY))
			return 0;

		if (signal_pending(current))
			return -EINTR;

		/* shutting down? */
		if (!netif_running(stir->netdev)
		    || !netif_device_present(stir->netdev))
			return -ESHUTDOWN;

		/* only waiting for some space */
		if (space >= 0 && STIR_FIFO_SIZE - 4 > space + count)
			return 0;

		/* estimate transfer time for remaining chars */
		msleep((count * 8000) / stir->speed);
	}
			
	err = write_reg(stir, REG_FIFOCTL, FIFOCTL_CLR);
	if (err) 
		return err;
	err = write_reg(stir, REG_FIFOCTL, 0);
	if (err)
		return err;

	return 0;
}


/* Wait for turnaround delay before starting transmit.  */
static void turnaround_delay(const struct stir_cb *stir, long us)
{
	long ticks;
	struct timeval now;

	if (us <= 0)
		return;

	do_gettimeofday(&now);
	if (now.tv_sec - stir->rx_time.tv_sec > 0)
		us -= USEC_PER_SEC;
	us -= now.tv_usec - stir->rx_time.tv_usec;
	if (us < 10)
		return;

	ticks = us / (1000000 / HZ);
	if (ticks > 0)
		schedule_timeout_interruptible(1 + ticks);
	else
		udelay(us);
}

/*
 * Start receiver by submitting a request to the receive pipe.
 * If nothing is available it will return after rx_interval.
 */
static int receive_start(struct stir_cb *stir)
{
	/* reset state */
	stir->receiving = 1;

	stir->rx_buff.in_frame = FALSE;
	stir->rx_buff.state = OUTSIDE_FRAME;

	stir->rx_urb->status = 0;
	return usb_submit_urb(stir->rx_urb, GFP_KERNEL);
}

/* Stop all pending receive Urb's */
static void receive_stop(struct stir_cb *stir)
{
	stir->receiving = 0;
	usb_kill_urb(stir->rx_urb);

	if (stir->rx_buff.in_frame) 
		stir->stats.collisions++;
}
/*
 * Wrap data in socket buffer and send it.
 */
static void stir_send(struct stir_cb *stir, struct sk_buff *skb)
{
	unsigned wraplen;
	int first_frame = 0;

	/* if receiving, need to turnaround */
	if (stir->receiving) {
		receive_stop(stir);
		turnaround_delay(stir, irda_get_mtt(skb));
		first_frame = 1;
	}

	if (isfir(stir->speed))
		wraplen = wrap_fir_skb(skb, stir->io_buf);
	else
		wraplen = wrap_sir_skb(skb, stir->io_buf);
		
	/* check for space available in fifo */
	if (!first_frame)
		fifo_txwait(stir, wraplen);

	stir->stats.tx_packets++;
	stir->stats.tx_bytes += skb->len;
	stir->netdev->trans_start = jiffies;
	pr_debug("send %d (%d)\n", skb->len, wraplen);

	if (usb_bulk_msg(stir->usbdev, usb_sndbulkpipe(stir->usbdev, 1),
			 stir->io_buf, wraplen,
			 NULL, TRANSMIT_TIMEOUT))
		stir->stats.tx_errors++;
}

/*
 * Transmit state machine thread
 */
static int stir_transmit_thread(void *arg)
{
	struct stir_cb *stir = arg;
	struct net_device *dev = stir->netdev;
	struct sk_buff *skb;

        while (!kthread_should_stop()) {
#ifdef CONFIG_PM
		/* if suspending, then power off and wait */
		if (unlikely(freezing(current))) {
			if (stir->receiving)
				receive_stop(stir);
			else
				fifo_txwait(stir, -1);

			write_reg(stir, REG_CTRL1, CTRL1_TXPWD|CTRL1_RXPWD);

			refrigerator();

			if (change_speed(stir, stir->speed))
				break;
		}
#endif

		/* if something to send? */
		skb = xchg(&stir->tx_pending, NULL);
		if (skb) {
			unsigned new_speed = irda_get_next_speed(skb);
			netif_wake_queue(dev);

			if (skb->len > 0)
				stir_send(stir, skb);
			dev_kfree_skb(skb);

			if ((new_speed != -1) && (stir->speed != new_speed)) {
				if (fifo_txwait(stir, -1) ||
				    change_speed(stir, new_speed))
					break;
			}
			continue;
		}

		/* nothing to send? start receiving */
		if (!stir->receiving 
		    && irda_device_txqueue_empty(dev)) {
			/* Wait otherwise chip gets confused. */
			if (fifo_txwait(stir, -1))
				break;

			if (unlikely(receive_start(stir))) {
				if (net_ratelimit())
					info("%s: receive usb submit failed",
					     stir->netdev->name);
				stir->receiving = 0;
				msleep(10);
				continue;
			}
		}

		/* sleep if nothing to send */
                set_current_state(TASK_INTERRUPTIBLE);
                schedule();

	}
        return 0;
}


/*
 * USB bulk receive completion callback.
 * Wakes up every ms (usb round trip) with wrapped 
 * data.
 */
static void stir_rcv_irq(struct urb *urb)
{
	struct stir_cb *stir = urb->context;
	int err;

	/* in process of stopping, just drop data */
	if (!netif_running(stir->netdev))
		return;

	/* unlink, shutdown, unplug, other nasties */
	if (urb->status != 0) 
		return;

	if (urb->actual_length > 0) {
		pr_debug("receive %d\n", urb->actual_length);
		unwrap_chars(stir, urb->transfer_buffer,
			     urb->actual_length);
		
		stir->netdev->last_rx = jiffies;
		do_gettimeofday(&stir->rx_time);
	}

	/* kernel thread is stopping receiver don't resubmit */
	if (!stir->receiving)
		return;

	/* resubmit existing urb */
	err = usb_submit_urb(urb, GFP_ATOMIC);

	/* in case of error, the kernel thread will restart us */
	if (err) {
		warn("%s: usb receive submit error: %d",
			stir->netdev->name, err);
		stir->receiving = 0;
		wake_up_process(stir->thread);
	}
}

/*
 * Function stir_net_open (dev)
 *
 *    Network device is taken up. Usually this is done by "ifconfig irda0 up"
 */
static int stir_net_open(struct net_device *netdev)
{
	struct stir_cb *stir = netdev_priv(netdev);
	int err;
	char hwname[16];

	err = usb_clear_halt(stir->usbdev, usb_sndbulkpipe(stir->usbdev, 1));
	if (err)
		goto err_out1;
	err = usb_clear_halt(stir->usbdev, usb_rcvbulkpipe(stir->usbdev, 2));
	if (err)
		goto err_out1;

	err = change_speed(stir, 9600);
	if (err)
		goto err_out1;

	err = -ENOMEM;

	/* Initialize for SIR/FIR to copy data directly into skb.  */
	stir->receiving = 0;
	stir->rx_buff.truesize = IRDA_SKB_MAX_MTU;
	stir->rx_buff.skb = dev_alloc_skb(IRDA_SKB_MAX_MTU);
	if (!stir->rx_buff.skb) 
		goto err_out1;

	skb_reserve(stir->rx_buff.skb, 1);
	stir->rx_buff.head = stir->rx_buff.skb->data;
	do_gettimeofday(&stir->rx_time);

	stir->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!stir->rx_urb) 
		goto err_out2;

	stir->io_buf = kmalloc(STIR_FIFO_SIZE, GFP_KERNEL);
	if (!stir->io_buf)
		goto err_out3;

	usb_fill_bulk_urb(stir->rx_urb, stir->usbdev,
			  usb_rcvbulkpipe(stir->usbdev, 2),
			  stir->io_buf, STIR_FIFO_SIZE,
			  stir_rcv_irq, stir);

	stir->fifo_status = kmalloc(FIFO_REGS_SIZE, GFP_KERNEL);
	if (!stir->fifo_status) 
		goto err_out4;
		
	/*
	 * Now that everything should be initialized properly,
	 * Open new IrLAP layer instance to take care of us...
	 * Note : will send immediately a speed change...
	 */
	sprintf(hwname, "usb#%d", stir->usbdev->devnum);
	stir->irlap = irlap_open(netdev, &stir->qos, hwname);
	if (!stir->irlap) {
		err("stir4200: irlap_open failed");
		goto err_out5;
	}

	/** Start kernel thread for transmit.  */
	stir->thread = kthread_run(stir_transmit_thread, stir,
				   "%s", stir->netdev->name);
        if (IS_ERR(stir->thread)) {
                err = PTR_ERR(stir->thread);
		err("stir4200: unable to start kernel thread");
		goto err_out6;
	}

	netif_start_queue(netdev);

	return 0;

 err_out6:
	irlap_close(stir->irlap);
 err_out5:
	kfree(stir->fifo_status);
 err_out4:
	kfree(stir->io_buf);
 err_out3:
	usb_free_urb(stir->rx_urb);
 err_out2:
	kfree_skb(stir->rx_buff.skb);
 err_out1:
	return err;
}

/*
 * Function stir_net_close (stir)
 *
 *    Network device is taken down. Usually this is done by
 *    "ifconfig irda0 down"
 */
static int stir_net_close(struct net_device *netdev)
{
	struct stir_cb *stir = netdev_priv(netdev);

	/* Stop transmit processing */
	netif_stop_queue(netdev);

	/* Kill transmit thread */
	kthread_stop(stir->thread);
	kfree(stir->fifo_status);

	/* Mop up receive urb's */
	usb_kill_urb(stir->rx_urb);
	
	kfree(stir->io_buf);
	usb_free_urb(stir->rx_urb);
	kfree_skb(stir->rx_buff.skb);

	/* Stop and remove instance of IrLAP */
	if (stir->irlap)
		irlap_close(stir->irlap);

	stir->irlap = NULL;

	return 0;
}

/*
 * IOCTLs : Extra out-of-band network commands...
 */
static int stir_net_ioctl(struct net_device *netdev, struct ifreq *rq, int cmd)
{
	struct if_irda_req *irq = (struct if_irda_req *) rq;
	struct stir_cb *stir = netdev_priv(netdev);
	int ret = 0;

	switch (cmd) {
	case SIOCSBANDWIDTH: /* Set bandwidth */
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

		/* Check if the device is still there */
		if (netif_device_present(stir->netdev))
			ret = change_speed(stir, irq->ifr_baudrate);
		break;

	case SIOCSMEDIABUSY: /* Set media busy */
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

		/* Check if the IrDA stack is still there */
		if (netif_running(stir->netdev))
			irda_device_set_media_busy(stir->netdev, TRUE);
		break;

	case SIOCGRECEIVING:
		/* Only approximately true */
		irq->ifr_receiving = stir->receiving;
		break;

	default:
		ret = -EOPNOTSUPP;
	}

	return ret;
}

/*
 * Get device stats (for /proc/net/dev and ifconfig)
 */
static struct net_device_stats *stir_net_get_stats(struct net_device *netdev)
{
	struct stir_cb *stir = netdev_priv(netdev);
	return &stir->stats;
}

/*
 * This routine is called by the USB subsystem for each new device
 * in the system. We need to check if the device is ours, and in
 * this case start handling it.
 * Note : it might be worth protecting this function by a global
 * spinlock... Or not, because maybe USB already deal with that...
 */
static int stir_probe(struct usb_interface *intf,
		      const struct usb_device_id *id)
{
	struct usb_device *dev = interface_to_usbdev(intf);
	struct stir_cb *stir = NULL;
	struct net_device *net;
	int ret = -ENOMEM;

	/* Allocate network device container. */
	net = alloc_irdadev(sizeof(*stir));
	if(!net)
		goto err_out1;

	SET_MODULE_OWNER(net);
	SET_NETDEV_DEV(net, &intf->dev);
	stir = netdev_priv(net);
	stir->netdev = net;
	stir->usbdev = dev;

	ret = usb_reset_configuration(dev);
	if (ret != 0) {
		err("stir4200: usb reset configuration failed");
		goto err_out2;
	}

	printk(KERN_INFO "SigmaTel STIr4200 IRDA/USB found at address %d, "
		"Vendor: %x, Product: %x\n",
	       dev->devnum, le16_to_cpu(dev->descriptor.idVendor),
	       le16_to_cpu(dev->descriptor.idProduct));

	/* Initialize QoS for this device */
	irda_init_max_qos_capabilies(&stir->qos);

	/* That's the Rx capability. */
	stir->qos.baud_rate.bits       &= IR_2400 | IR_9600 | IR_19200 |
					 IR_38400 | IR_57600 | IR_115200 |
					 (IR_4000000 << 8);
	stir->qos.min_turn_time.bits   &= qos_mtt_bits;
	irda_qos_bits_to_value(&stir->qos);

	/* Override the network functions we need to use */
	net->hard_start_xmit = stir_hard_xmit;
	net->open            = stir_net_open;
	net->stop            = stir_net_close;
	net->get_stats	     = stir_net_get_stats;
	net->do_ioctl        = stir_net_ioctl;

	ret = register_netdev(net);
	if (ret != 0)
		goto err_out2;

	info("IrDA: Registered SigmaTel device %s", net->name);

	usb_set_intfdata(intf, stir);

	return 0;

err_out2:
	free_netdev(net);
err_out1:
	return ret;
}

/*
 * The current device is removed, the USB layer tell us to shut it down...
 */
static void stir_disconnect(struct usb_interface *intf)
{
	struct stir_cb *stir = usb_get_intfdata(intf);

	if (!stir)
		return;

	unregister_netdev(stir->netdev);
	free_netdev(stir->netdev);

	usb_set_intfdata(intf, NULL);
}

#ifdef CONFIG_PM
/* USB suspend, so power off the transmitter/receiver */
static int stir_suspend(struct usb_interface *intf, pm_message_t message)
{
	struct stir_cb *stir = usb_get_intfdata(intf);

	netif_device_detach(stir->netdev);
	return 0;
}

/* Coming out of suspend, so reset hardware */
static int stir_resume(struct usb_interface *intf)
{
	struct stir_cb *stir = usb_get_intfdata(intf);

	netif_device_attach(stir->netdev);

	/* receiver restarted when send thread wakes up */
	return 0;
}
#endif

/*
 * USB device callbacks
 */
static struct usb_driver irda_driver = {
	.name		= "stir4200",
	.probe		= stir_probe,
	.disconnect	= stir_disconnect,
	.id_table	= dongles,
#ifdef CONFIG_PM
	.suspend	= stir_suspend,
	.resume		= stir_resume,
#endif
};

/*
 * Module insertion
 */
static int __init stir_init(void)
{
	return usb_register(&irda_driver);
}
module_init(stir_init);

/*
 * Module removal
 */
static void __exit stir_cleanup(void)
{
	/* Deregister the driver and remove all pending instances */
	usb_deregister(&irda_driver);
}
module_exit(stir_cleanup);