usbatm.c

底层驱动开发

	clear_bit(ATM_VF_READY, &vcc->flags);
	clear_bit(ATM_VF_PARTIAL, &vcc->flags);
	clear_bit(ATM_VF_ADDR, &vcc->flags);

	up(&instance->serialize);

	atm_dbg(instance, "%s successful\n", __func__);
}

static int usbatm_atm_ioctl(struct atm_dev *dev, unsigned int cmd,
			  void __user * arg)
{
	switch (cmd) {
	case ATM_QUERYLOOP:
		return put_user(ATM_LM_NONE, (int __user *)arg) ? -EFAULT : 0;
	default:
		return -ENOIOCTLCMD;
	}
}

static int usbatm_atm_init(struct usbatm_data *instance)
{
	struct atm_dev *atm_dev;
	int ret, i;

	/* ATM init */
	atm_dev = atm_dev_register(instance->driver_name, &usbatm_atm_devops, -1, NULL);
	if (!atm_dev) {
		usb_dbg(instance, "%s: failed to register ATM device!\n", __func__);
		return -1;
	}

	instance->atm_dev = atm_dev;

	atm_dev->ci_range.vpi_bits = ATM_CI_MAX;
	atm_dev->ci_range.vci_bits = ATM_CI_MAX;
	atm_dev->signal = ATM_PHY_SIG_UNKNOWN;

	/* temp init ATM device, set to 128kbit */
	atm_dev->link_rate = 128 * 1000 / 424;

	if (instance->driver->atm_start && ((ret = instance->driver->atm_start(instance, atm_dev)) < 0)) {
		atm_dbg(instance, "%s: atm_start failed: %d!\n", __func__, ret);
		goto fail;
	}

	/* ready for ATM callbacks */
	usbatm_get_instance(instance);	/* dropped in usbatm_atm_dev_close */
	mb();
	atm_dev->dev_data = instance;

	/* submit all rx URBs */
	for (i = 0; i < num_rcv_urbs; i++)
		usbatm_submit_urb(instance->urbs[i]);

	return 0;

 fail:
	instance->atm_dev = NULL;
	shutdown_atm_dev(atm_dev); /* usbatm_atm_dev_close will eventually be called */
	return ret;
}


/**********
**  USB  **
**********/

static int usbatm_do_heavy_init(void *arg)
{
	struct usbatm_data *instance = arg;
	int ret;

	daemonize(instance->driver->driver_name);
	allow_signal(SIGTERM);

	complete(&instance->thread_started);

	ret = instance->driver->heavy_init(instance, instance->usb_intf);

	if (!ret)
		ret = usbatm_atm_init(instance);

	down(&instance->serialize);
	instance->thread_pid = -1;
	up(&instance->serialize);

	complete_and_exit(&instance->thread_exited, ret);
}

static int usbatm_heavy_init(struct usbatm_data *instance)
{
	int ret = kernel_thread(usbatm_do_heavy_init, instance, CLONE_KERNEL);

	if (ret < 0) {
		usb_dbg(instance, "%s: failed to create kernel_thread (%d)!\n", __func__, ret);
		return ret;
	}

	down(&instance->serialize);
	instance->thread_pid = ret;
	up(&instance->serialize);

	wait_for_completion(&instance->thread_started);

	return 0;
}

static void usbatm_tasklet_schedule(unsigned long data)
{
	tasklet_schedule((struct tasklet_struct *) data);
}

static inline void usbatm_init_channel(struct usbatm_channel *channel)
{
	spin_lock_init(&channel->lock);
	INIT_LIST_HEAD(&channel->list);
	channel->delay.function = usbatm_tasklet_schedule;
	channel->delay.data = (unsigned long) &channel->tasklet;
	init_timer(&channel->delay);
}

int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
		     struct usbatm_driver *driver)
{
	struct device *dev = &intf->dev;
	struct usb_device *usb_dev = interface_to_usbdev(intf);
	struct usbatm_data *instance;
	char *buf;
	int error = -ENOMEM;
	int i, length;
	int need_heavy;

	dev_dbg(dev, "%s: trying driver %s with vendor=0x%x, product=0x%x, ifnum %d\n",
			__func__, driver->driver_name,
			le16_to_cpu(usb_dev->descriptor.idVendor),
			le16_to_cpu(usb_dev->descriptor.idProduct),
			intf->altsetting->desc.bInterfaceNumber);

	/* instance init */
	instance = kzalloc(sizeof(*instance) + sizeof(struct urb *) * (num_rcv_urbs + num_snd_urbs), GFP_KERNEL);
	if (!instance) {
		dev_dbg(dev, "%s: no memory for instance data!\n", __func__);
		return -ENOMEM;
	}

	/* public fields */

	instance->driver = driver;
	snprintf(instance->driver_name, sizeof(instance->driver_name), driver->driver_name);

	instance->usb_dev = usb_dev;
	instance->usb_intf = intf;

	buf = instance->description;
	length = sizeof(instance->description);

	if ((i = usb_string(usb_dev, usb_dev->descriptor.iProduct, buf, length)) < 0)
		goto bind;

	buf += i;
	length -= i;

	i = scnprintf(buf, length, " (");
	buf += i;
	length -= i;

	if (length <= 0 || (i = usb_make_path(usb_dev, buf, length)) < 0)
		goto bind;

	buf += i;
	length -= i;

	snprintf(buf, length, ")");

 bind:
	need_heavy = 1;
	if (driver->bind && (error = driver->bind(instance, intf, id, &need_heavy)) < 0) {
			dev_dbg(dev, "%s: bind failed: %d!\n", __func__, error);
			goto fail_free;
	}

	/* private fields */

	kref_init(&instance->refcount);		/* dropped in usbatm_usb_disconnect */
	init_MUTEX(&instance->serialize);

	instance->thread_pid = -1;
	init_completion(&instance->thread_started);
	init_completion(&instance->thread_exited);

	INIT_LIST_HEAD(&instance->vcc_list);

	usbatm_init_channel(&instance->rx_channel);
	usbatm_init_channel(&instance->tx_channel);
	tasklet_init(&instance->rx_channel.tasklet, usbatm_rx_process, (unsigned long)instance);
	tasklet_init(&instance->tx_channel.tasklet, usbatm_tx_process, (unsigned long)instance);
	instance->rx_channel.endpoint = usb_rcvbulkpipe(usb_dev, driver->in);
	instance->tx_channel.endpoint = usb_sndbulkpipe(usb_dev, driver->out);
	instance->rx_channel.stride = ATM_CELL_SIZE + driver->rx_padding;
	instance->tx_channel.stride = ATM_CELL_SIZE + driver->tx_padding;
	instance->rx_channel.buf_size = rcv_buf_size * instance->rx_channel.stride;
	instance->tx_channel.buf_size = snd_buf_size * instance->tx_channel.stride;
	instance->rx_channel.usbatm = instance->tx_channel.usbatm = instance;

	skb_queue_head_init(&instance->sndqueue);

	for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
		struct urb *urb;
		u8 *buffer;
		unsigned int iso_packets = 0, iso_size = 0;
		struct usbatm_channel *channel = i < num_rcv_urbs ?
			&instance->rx_channel : &instance->tx_channel;

		if (usb_pipeisoc(channel->endpoint)) {
			/* don't expect iso out endpoints */
			iso_size = usb_maxpacket(instance->usb_dev, channel->endpoint, 0);
			iso_size -= iso_size % channel->stride;	/* alignment */
			BUG_ON(!iso_size);
			iso_packets = (channel->buf_size - 1) / iso_size + 1;
		}

		urb = usb_alloc_urb(iso_packets, GFP_KERNEL);
		if (!urb) {
			dev_dbg(dev, "%s: no memory for urb %d!\n", __func__, i);
			goto fail_unbind;
		}

		instance->urbs[i] = urb;

		buffer = kmalloc(channel->buf_size, GFP_KERNEL);
		if (!buffer) {
			dev_dbg(dev, "%s: no memory for buffer %d!\n", __func__, i);
			goto fail_unbind;
		}
		memset(buffer, 0, channel->buf_size);

		usb_fill_bulk_urb(urb, instance->usb_dev, channel->endpoint,
				  buffer, channel->buf_size, usbatm_complete, channel);
		if (iso_packets) {
			int j;
			urb->interval = 1;
			urb->transfer_flags = URB_ISO_ASAP;
			urb->number_of_packets = iso_packets;
			for (j = 0; j < iso_packets; j++) {
				urb->iso_frame_desc[j].offset = iso_size * j;
				urb->iso_frame_desc[j].length = min_t(int, iso_size,
								      channel->buf_size - urb->iso_frame_desc[j].offset);
			}
		}

		/* put all tx URBs on the list of spares */
		if (i >= num_rcv_urbs)
			list_add_tail(&urb->urb_list, &channel->list);

		vdbg("%s: alloced buffer 0x%p buf size %u urb 0x%p",
		     __func__, urb->transfer_buffer, urb->transfer_buffer_length, urb);
	}

	if (need_heavy && driver->heavy_init) {
		error = usbatm_heavy_init(instance);
	} else {
		complete(&instance->thread_exited);	/* pretend that heavy_init was run */
		error = usbatm_atm_init(instance);
	}

	if (error < 0)
		goto fail_unbind;

	usb_get_dev(usb_dev);
	usb_set_intfdata(intf, instance);

	return 0;

 fail_unbind:
	if (instance->driver->unbind)
		instance->driver->unbind(instance, intf);
 fail_free:
	for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
		if (instance->urbs[i])
			kfree(instance->urbs[i]->transfer_buffer);
		usb_free_urb(instance->urbs[i]);
	}

	kfree (instance);

	return error;
}
EXPORT_SYMBOL_GPL(usbatm_usb_probe);

void usbatm_usb_disconnect(struct usb_interface *intf)
{
	struct device *dev = &intf->dev;
	struct usbatm_data *instance = usb_get_intfdata(intf);
	int i;

	dev_dbg(dev, "%s entered\n", __func__);

	if (!instance) {
		dev_dbg(dev, "%s: NULL instance!\n", __func__);
		return;
	}

	usb_set_intfdata(intf, NULL);

	down(&instance->serialize);
	if (instance->thread_pid >= 0)
		kill_proc(instance->thread_pid, SIGTERM, 1);
	up(&instance->serialize);

	wait_for_completion(&instance->thread_exited);

	tasklet_disable(&instance->rx_channel.tasklet);
	tasklet_disable(&instance->tx_channel.tasklet);

	for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++)
		usb_kill_urb(instance->urbs[i]);

	del_timer_sync(&instance->rx_channel.delay);
	del_timer_sync(&instance->tx_channel.delay);

	if (instance->atm_dev && instance->driver->atm_stop)
		instance->driver->atm_stop(instance, instance->atm_dev);

	if (instance->driver->unbind)
		instance->driver->unbind(instance, intf);

	instance->driver_data = NULL;

	/* turn usbatm_[rt]x_process into noop */
	/* no need to take the spinlock */
	INIT_LIST_HEAD(&instance->rx_channel.list);
	INIT_LIST_HEAD(&instance->tx_channel.list);

	tasklet_enable(&instance->rx_channel.tasklet);
	tasklet_enable(&instance->tx_channel.tasklet);

	for (i = 0; i < num_rcv_urbs + num_snd_urbs; i++) {
		kfree(instance->urbs[i]->transfer_buffer);
		usb_free_urb(instance->urbs[i]);
	}

	/* ATM finalize */
	if (instance->atm_dev)
		shutdown_atm_dev(instance->atm_dev);

	usbatm_put_instance(instance);	/* taken in usbatm_usb_probe */
}
EXPORT_SYMBOL_GPL(usbatm_usb_disconnect);


/***********
**  init  **
***********/

static int __init usbatm_usb_init(void)
{
	dbg("%s: driver version %s", __func__, DRIVER_VERSION);

	if (sizeof(struct usbatm_control) > sizeof(((struct sk_buff *) 0)->cb)) {
		printk(KERN_ERR "%s unusable with this kernel!\n", usbatm_driver_name);
		return -EIO;
	}

	if ((num_rcv_urbs > UDSL_MAX_RCV_URBS)
	    || (num_snd_urbs > UDSL_MAX_SND_URBS)
	    || (rcv_buf_size < 1)
	    || (rcv_buf_size > UDSL_MAX_RCV_BUF_SIZE)
	    || (snd_buf_size < 1)
	    || (snd_buf_size > UDSL_MAX_SND_BUF_SIZE))
		return -EINVAL;

	return 0;
}
module_init(usbatm_usb_init);

static void __exit usbatm_usb_exit(void)
{
	dbg("%s", __func__);
}
module_exit(usbatm_usb_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
MODULE_VERSION(DRIVER_VERSION);

/************
**  debug  **
************/

#ifdef VERBOSE_DEBUG
static int usbatm_print_packet(const unsigned char *data, int len)
{
	unsigned char buffer[256];
	int i = 0, j = 0;

	for (i = 0; i < len;) {
		buffer[0] = '\0';
		sprintf(buffer, "%.3d :", i);
		for (j = 0; (j < 16) && (i < len); j++, i++) {
			sprintf(buffer, "%s %2.2x", buffer, data[i]);
		}
		dbg("%s", buffer);
	}
	return i;
}
#endif