usbatm.c

LINUX 2.6.17.4的源码

				       u8 *target, unsigned int avail_space)
{
	struct usbatm_control *ctrl = UDSL_SKB(skb);
	struct atm_vcc *vcc = ctrl->atm.vcc;
	unsigned int bytes_written;
	unsigned int stride = instance->tx_channel.stride;

	vdbg("%s: skb->len=%d, avail_space=%u", __func__, skb->len, avail_space);
	UDSL_ASSERT(!(avail_space % stride));

	for (bytes_written = 0; bytes_written < avail_space && ctrl->len;
	     bytes_written += stride, target += stride) {
		unsigned int data_len = min_t(unsigned int, skb->len, ATM_CELL_PAYLOAD);
		unsigned int left = ATM_CELL_PAYLOAD - data_len;
		u8 *ptr = target;

		ptr[0] = vcc->vpi >> 4;
		ptr[1] = (vcc->vpi << 4) | (vcc->vci >> 12);
		ptr[2] = vcc->vci >> 4;
		ptr[3] = vcc->vci << 4;
		ptr[4] = 0xec;
		ptr += ATM_CELL_HEADER;

		memcpy(ptr, skb->data, data_len);
		ptr += data_len;
		__skb_pull(skb, data_len);

		if(!left)
			continue;

		memset(ptr, 0, left);

		if (left >= ATM_AAL5_TRAILER) {	/* trailer will go in this cell */
			u8 *trailer = target + ATM_CELL_SIZE - ATM_AAL5_TRAILER;
			/* trailer[0] = 0;		UU = 0 */
			/* trailer[1] = 0;		CPI = 0 */
			trailer[2] = ctrl->len >> 8;
			trailer[3] = ctrl->len;

			ctrl->crc = ~ crc32_be(ctrl->crc, ptr, left - 4);

			trailer[4] = ctrl->crc >> 24;
			trailer[5] = ctrl->crc >> 16;
			trailer[6] = ctrl->crc >> 8;
			trailer[7] = ctrl->crc;

			target[3] |= 0x2;	/* adjust PTI */

			ctrl->len = 0;		/* tag this skb finished */
		}
		else
			ctrl->crc = crc32_be(ctrl->crc, ptr, left);
	}

	return bytes_written;
}


/**************
**  receive  **
**************/

static void usbatm_rx_process(unsigned long data)
{
	struct usbatm_data *instance = (struct usbatm_data *)data;
	struct urb *urb;

	while ((urb = usbatm_pop_urb(&instance->rx_channel))) {
		vdbg("%s: processing urb 0x%p", __func__, urb);

		if (usb_pipeisoc(urb->pipe)) {
			unsigned char *merge_start = NULL;
			unsigned int merge_length = 0;
			const unsigned int packet_size = instance->rx_channel.packet_size;
			int i;

			for (i = 0; i < urb->number_of_packets; i++) {
				if (!urb->iso_frame_desc[i].status) {
					unsigned int actual_length = urb->iso_frame_desc[i].actual_length;

					UDSL_ASSERT(actual_length <= packet_size);

					if (!merge_length)
						merge_start = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset;
					merge_length += actual_length;
					if (merge_length && (actual_length < packet_size)) {
						usbatm_extract_cells(instance, merge_start, merge_length);
						merge_length = 0;
					}
				} else {
					atm_rldbg(instance, "%s: status %d in frame %d!\n", __func__, urb->status, i);
					if (merge_length)
						usbatm_extract_cells(instance, merge_start, merge_length);
					merge_length = 0;
					instance->buf_usage = 0;
				}
			}

			if (merge_length)
				usbatm_extract_cells(instance, merge_start, merge_length);
		} else
			if (!urb->status)
				usbatm_extract_cells(instance, urb->transfer_buffer, urb->actual_length);
			else
				instance->buf_usage = 0;

		if (usbatm_submit_urb(urb))
			return;
	}
}


/***********
**  send  **
***********/

static void usbatm_tx_process(unsigned long data)
{
	struct usbatm_data *instance = (struct usbatm_data *)data;
	struct sk_buff *skb = instance->current_skb;
	struct urb *urb = NULL;
	const unsigned int buf_size = instance->tx_channel.buf_size;
	unsigned int bytes_written = 0;
	u8 *buffer = NULL;

	if (!skb)
		skb = skb_dequeue(&instance->sndqueue);

	while (skb) {
		if (!urb) {
			urb = usbatm_pop_urb(&instance->tx_channel);
			if (!urb)
				break;		/* no more senders */
			buffer = urb->transfer_buffer;
			bytes_written = (urb->status == -EAGAIN) ?
				urb->transfer_buffer_length : 0;
		}

		bytes_written += usbatm_write_cells(instance, skb,
						  buffer + bytes_written,
						  buf_size - bytes_written);

		vdbg("%s: wrote %u bytes from skb 0x%p to urb 0x%p",
		     __func__, bytes_written, skb, urb);

		if (!UDSL_SKB(skb)->len) {
			struct atm_vcc *vcc = UDSL_SKB(skb)->atm.vcc;

			usbatm_pop(vcc, skb);
			atomic_inc(&vcc->stats->tx);

			skb = skb_dequeue(&instance->sndqueue);
		}

		if (bytes_written == buf_size || (!skb && bytes_written)) {
			urb->transfer_buffer_length = bytes_written;

			if (usbatm_submit_urb(urb))
				break;
			urb = NULL;
		}
	}

	instance->current_skb = skb;
}

static void usbatm_cancel_send(struct usbatm_data *instance,
			       struct atm_vcc *vcc)
{
	struct sk_buff *skb, *n;

	atm_dbg(instance, "%s entered\n", __func__);
	spin_lock_irq(&instance->sndqueue.lock);
	for (skb = instance->sndqueue.next, n = skb->next;
	     skb != (struct sk_buff *)&instance->sndqueue;
	     skb = n, n = skb->next)
		if (UDSL_SKB(skb)->atm.vcc == vcc) {
			atm_dbg(instance, "%s: popping skb 0x%p\n", __func__, skb);
			__skb_unlink(skb, &instance->sndqueue);
			usbatm_pop(vcc, skb);
		}
	spin_unlock_irq(&instance->sndqueue.lock);

	tasklet_disable(&instance->tx_channel.tasklet);
	if ((skb = instance->current_skb) && (UDSL_SKB(skb)->atm.vcc == vcc)) {
		atm_dbg(instance, "%s: popping current skb (0x%p)\n", __func__, skb);
		instance->current_skb = NULL;
		usbatm_pop(vcc, skb);
	}
	tasklet_enable(&instance->tx_channel.tasklet);
	atm_dbg(instance, "%s done\n", __func__);
}

static int usbatm_atm_send(struct atm_vcc *vcc, struct sk_buff *skb)
{
	struct usbatm_data *instance = vcc->dev->dev_data;
	struct usbatm_control *ctrl = UDSL_SKB(skb);
	int err;

	vdbg("%s called (skb 0x%p, len %u)", __func__, skb, skb->len);

	/* racy disconnection check - fine */
	if (!instance || instance->disconnected) {
#ifdef DEBUG
		if (printk_ratelimit())
			printk(KERN_DEBUG "%s: %s!\n", __func__, instance ? "disconnected" : "NULL instance");
#endif
		err = -ENODEV;
		goto fail;
	}

	if (vcc->qos.aal != ATM_AAL5) {
		atm_rldbg(instance, "%s: unsupported ATM type %d!\n", __func__, vcc->qos.aal);
		err = -EINVAL;
		goto fail;
	}

	if (skb->len > ATM_MAX_AAL5_PDU) {
		atm_rldbg(instance, "%s: packet too long (%d vs %d)!\n",
				__func__, skb->len, ATM_MAX_AAL5_PDU);
		err = -EINVAL;
		goto fail;
	}

	PACKETDEBUG(skb->data, skb->len);

	/* initialize the control block */
	ctrl->atm.vcc = vcc;
	ctrl->len = skb->len;
	ctrl->crc = crc32_be(~0, skb->data, skb->len);

	skb_queue_tail(&instance->sndqueue, skb);
	tasklet_schedule(&instance->tx_channel.tasklet);

	return 0;

 fail:
	usbatm_pop(vcc, skb);
	return err;
}


/********************
**  bean counting  **
********************/

static void usbatm_destroy_instance(struct kref *kref)
{
	struct usbatm_data *instance = container_of(kref, struct usbatm_data, refcount);

	dbg("%s", __func__);

	tasklet_kill(&instance->rx_channel.tasklet);
	tasklet_kill(&instance->tx_channel.tasklet);
	usb_put_dev(instance->usb_dev);
	kfree(instance);
}

static void usbatm_get_instance(struct usbatm_data *instance)
{
	dbg("%s", __func__);

	kref_get(&instance->refcount);
}

static void usbatm_put_instance(struct usbatm_data *instance)
{
	dbg("%s", __func__);

	kref_put(&instance->refcount, usbatm_destroy_instance);
}


/**********
**  ATM  **
**********/

static void usbatm_atm_dev_close(struct atm_dev *atm_dev)
{
	struct usbatm_data *instance = atm_dev->dev_data;

	dbg("%s", __func__);

	if (!instance)
		return;

	atm_dev->dev_data = NULL; /* catch bugs */
	usbatm_put_instance(instance);	/* taken in usbatm_atm_init */
}

static int usbatm_atm_proc_read(struct atm_dev *atm_dev, loff_t * pos, char *page)
{
	struct usbatm_data *instance = atm_dev->dev_data;
	int left = *pos;

	if (!instance) {
		dbg("%s: NULL instance!", __func__);
		return -ENODEV;
	}

	if (!left--)
		return sprintf(page, "%s\n", instance->description);

	if (!left--)
		return sprintf(page, "MAC: %02x:%02x:%02x:%02x:%02x:%02x\n",
			       atm_dev->esi[0], atm_dev->esi[1],
			       atm_dev->esi[2], atm_dev->esi[3],
			       atm_dev->esi[4], atm_dev->esi[5]);

	if (!left--)
		return sprintf(page,
			       "AAL5: tx %d ( %d err ), rx %d ( %d err, %d drop )\n",
			       atomic_read(&atm_dev->stats.aal5.tx),
			       atomic_read(&atm_dev->stats.aal5.tx_err),
			       atomic_read(&atm_dev->stats.aal5.rx),
			       atomic_read(&atm_dev->stats.aal5.rx_err),
			       atomic_read(&atm_dev->stats.aal5.rx_drop));

	if (!left--) {
		if (instance->disconnected)
			return sprintf(page, "Disconnected\n");
		else
			switch (atm_dev->signal) {
			case ATM_PHY_SIG_FOUND:
				return sprintf(page, "Line up\n");
			case ATM_PHY_SIG_LOST:
				return sprintf(page, "Line down\n");
			default:
				return sprintf(page, "Line state unknown\n");
			}
	}

	return 0;
}

static int usbatm_atm_open(struct atm_vcc *vcc)
{
	struct usbatm_data *instance = vcc->dev->dev_data;
	struct usbatm_vcc_data *new = NULL;
	int ret;
	int vci = vcc->vci;
	short vpi = vcc->vpi;

	if (!instance) {
		dbg("%s: NULL data!", __func__);
		return -ENODEV;
	}

	atm_dbg(instance, "%s: vpi %hd, vci %d\n", __func__, vpi, vci);

	/* only support AAL5 */
	if ((vcc->qos.aal != ATM_AAL5)) {
		atm_warn(instance, "%s: unsupported ATM type %d!\n", __func__, vcc->qos.aal);
		return -EINVAL;
	}

	/* sanity checks */
	if ((vcc->qos.rxtp.max_sdu < 0) || (vcc->qos.rxtp.max_sdu > ATM_MAX_AAL5_PDU)) {
		atm_dbg(instance, "%s: max_sdu %d out of range!\n", __func__, vcc->qos.rxtp.max_sdu);
		return -EINVAL;
	}

	mutex_lock(&instance->serialize);	/* vs self, usbatm_atm_close, usbatm_usb_disconnect */

	if (instance->disconnected) {
		atm_dbg(instance, "%s: disconnected!\n", __func__);
		ret = -ENODEV;
		goto fail;
	}

	if (usbatm_find_vcc(instance, vpi, vci)) {
		atm_dbg(instance, "%s: %hd/%d already in use!\n", __func__, vpi, vci);
		ret = -EADDRINUSE;
		goto fail;
	}

	if (!(new = kzalloc(sizeof(struct usbatm_vcc_data), GFP_KERNEL))) {
		atm_err(instance, "%s: no memory for vcc_data!\n", __func__);
		ret = -ENOMEM;
		goto fail;
	}

	new->vcc = vcc;
	new->vpi = vpi;
	new->vci = vci;

	new->sarb = alloc_skb(usbatm_pdu_length(vcc->qos.rxtp.max_sdu), GFP_KERNEL);
	if (!new->sarb) {
		atm_err(instance, "%s: no memory for SAR buffer!\n", __func__);
		ret = -ENOMEM;
		goto fail;
	}

	vcc->dev_data = new;

	tasklet_disable(&instance->rx_channel.tasklet);
	instance->cached_vcc = new;
	instance->cached_vpi = vpi;
	instance->cached_vci = vci;
	list_add(&new->list, &instance->vcc_list);
	tasklet_enable(&instance->rx_channel.tasklet);

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

	mutex_unlock(&instance->serialize);

	atm_dbg(instance, "%s: allocated vcc data 0x%p\n", __func__, new);

	return 0;

fail:
	kfree(new);
	mutex_unlock(&instance->serialize);
	return ret;
}

static void usbatm_atm_close(struct atm_vcc *vcc)
{
	struct usbatm_data *instance = vcc->dev->dev_data;
	struct usbatm_vcc_data *vcc_data = vcc->dev_data;

	if (!instance || !vcc_data) {
		dbg("%s: NULL data!", __func__);
		return;
	}

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

	atm_dbg(instance, "%s: deallocating vcc 0x%p with vpi %d vci %d\n",
		__func__, vcc_data, vcc_data->vpi, vcc_data->vci);

	usbatm_cancel_send(instance, vcc);

	mutex_lock(&instance->serialize);	/* vs self, usbatm_atm_open, usbatm_usb_disconnect */

	tasklet_disable(&instance->rx_channel.tasklet);
	if (instance->cached_vcc == vcc_data) {
		instance->cached_vcc = NULL;
		instance->cached_vpi = ATM_VPI_UNSPEC;
		instance->cached_vci = ATM_VCI_UNSPEC;
	}
	list_del(&vcc_data->list);
	tasklet_enable(&instance->rx_channel.tasklet);

	kfree_skb(vcc_data->sarb);
	vcc_data->sarb = NULL;

	kfree(vcc_data);
	vcc->dev_data = NULL;

	vcc->vpi = ATM_VPI_UNSPEC;
	vcc->vci = ATM_VCI_UNSPEC;
	clear_bit(ATM_VF_READY, &vcc->flags);
	clear_bit(ATM_VF_PARTIAL, &vcc->flags);
	clear_bit(ATM_VF_ADDR, &vcc->flags);

	mutex_unlock(&instance->serialize);

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