drivers/isdn/mISDN/hwchannel.c - third_party/linux - Git at Google

 /*
  *
  * Author	Karsten Keil <kkeil@novell.com>
  *
  * Copyright 2008  by Karsten Keil <kkeil@novell.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  */

 #include <linux/module.h>
 #include <linux/mISDNhw.h>

 static void
 dchannel_bh(struct work_struct *ws)
 {
 	struct dchannel	*dch  = container_of(ws, struct dchannel, workq);
 	struct sk_buff	*skb;
 	int		err;

 	if (test_and_clear_bit(FLG_RECVQUEUE, &dch->Flags)) {
 		while ((skb = skb_dequeue(&dch->rqueue))) {
 			if (likely(dch->dev.D.peer)) {
 				err = dch->dev.D.recv(dch->dev.D.peer, skb);
 				if (err)
 					dev_kfree_skb(skb);
 			} else
 				dev_kfree_skb(skb);
 		}
 	}
 	if (test_and_clear_bit(FLG_PHCHANGE, &dch->Flags)) {
 		if (dch->phfunc)
 			dch->phfunc(dch);
 	}
 }

 static void
 bchannel_bh(struct work_struct *ws)
 {
 	struct bchannel	*bch  = container_of(ws, struct bchannel, workq);
 	struct sk_buff	*skb;
 	int		err;

 	if (test_and_clear_bit(FLG_RECVQUEUE, &bch->Flags)) {
 		while ((skb = skb_dequeue(&bch->rqueue))) {
 			bch->rcount--;
 			if (likely(bch->ch.peer)) {
 				err = bch->ch.recv(bch->ch.peer, skb);
 				if (err)
 					dev_kfree_skb(skb);
 			} else
 				dev_kfree_skb(skb);
 		}
 	}
 }

 int
 mISDN_initdchannel(struct dchannel *ch, int maxlen, void *phf)
 {
 	test_and_set_bit(FLG_HDLC, &ch->Flags);
 	ch->maxlen = maxlen;
 	ch->hw = NULL;
 	ch->rx_skb = NULL;
 	ch->tx_skb = NULL;
 	ch->tx_idx = 0;
 	ch->phfunc = phf;
 	skb_queue_head_init(&ch->squeue);
 	skb_queue_head_init(&ch->rqueue);
 	INIT_LIST_HEAD(&ch->dev.bchannels);
 	INIT_WORK(&ch->workq, dchannel_bh);
 	return 0;
 }
 EXPORT_SYMBOL(mISDN_initdchannel);

 int
 mISDN_initbchannel(struct bchannel *ch, int maxlen)
 {
 	ch->Flags = 0;
 	ch->maxlen = maxlen;
 	ch->hw = NULL;
 	ch->rx_skb = NULL;
 	ch->tx_skb = NULL;
 	ch->tx_idx = 0;
 	skb_queue_head_init(&ch->rqueue);
 	ch->rcount = 0;
 	ch->next_skb = NULL;
 	INIT_WORK(&ch->workq, bchannel_bh);
 	return 0;
 }
 EXPORT_SYMBOL(mISDN_initbchannel);

 int
 mISDN_freedchannel(struct dchannel *ch)
 {
 	if (ch->tx_skb) {
 		dev_kfree_skb(ch->tx_skb);
 		ch->tx_skb = NULL;
 	}
 	if (ch->rx_skb) {
 		dev_kfree_skb(ch->rx_skb);
 		ch->rx_skb = NULL;
 	}
 	skb_queue_purge(&ch->squeue);
 	skb_queue_purge(&ch->rqueue);
 	flush_scheduled_work();
 	return 0;
 }
 EXPORT_SYMBOL(mISDN_freedchannel);

 int
 mISDN_freebchannel(struct bchannel *ch)
 {
 	if (ch->tx_skb) {
 		dev_kfree_skb(ch->tx_skb);
 		ch->tx_skb = NULL;
 	}
 	if (ch->rx_skb) {
 		dev_kfree_skb(ch->rx_skb);
 		ch->rx_skb = NULL;
 	}
 	if (ch->next_skb) {
 		dev_kfree_skb(ch->next_skb);
 		ch->next_skb = NULL;
 	}
 	skb_queue_purge(&ch->rqueue);
 	ch->rcount = 0;
 	flush_scheduled_work();
 	return 0;
 }
 EXPORT_SYMBOL(mISDN_freebchannel);

 static inline u_int
 get_sapi_tei(u_char *p)
 {
 	u_int	sapi, tei;

 	sapi = *p >> 2;
 	tei = p[1] >> 1;
 	return sapi | (tei << 8);
 }

 void
 recv_Dchannel(struct dchannel *dch)
 {
 	struct mISDNhead *hh;

 	if (dch->rx_skb->len < 2) { /* at least 2 for sapi / tei */
 		dev_kfree_skb(dch->rx_skb);
 		dch->rx_skb = NULL;
 		return;
 	}
 	hh = mISDN_HEAD_P(dch->rx_skb);
 	hh->prim = PH_DATA_IND;
 	hh->id = get_sapi_tei(dch->rx_skb->data);
 	skb_queue_tail(&dch->rqueue, dch->rx_skb);
 	dch->rx_skb = NULL;
 	schedule_event(dch, FLG_RECVQUEUE);
 }
 EXPORT_SYMBOL(recv_Dchannel);

 void
 recv_Echannel(struct dchannel *ech, struct dchannel *dch)
 {
 	struct mISDNhead *hh;

 	if (ech->rx_skb->len < 2) { /* at least 2 for sapi / tei */
 		dev_kfree_skb(ech->rx_skb);
 		ech->rx_skb = NULL;
 		return;
 	}
 	hh = mISDN_HEAD_P(ech->rx_skb);
 	hh->prim = PH_DATA_E_IND;
 	hh->id = get_sapi_tei(ech->rx_skb->data);
 	skb_queue_tail(&dch->rqueue, ech->rx_skb);
 	ech->rx_skb = NULL;
 	schedule_event(dch, FLG_RECVQUEUE);
 }
 EXPORT_SYMBOL(recv_Echannel);

 void
 recv_Bchannel(struct bchannel *bch, unsigned int id)
 {
 	struct mISDNhead *hh;

 	hh = mISDN_HEAD_P(bch->rx_skb);
 	hh->prim = PH_DATA_IND;
 	hh->id = id;
 	if (bch->rcount >= 64) {
 		printk(KERN_WARNING "B-channel %p receive queue overflow, "
 			"fushing!\n", bch);
 		skb_queue_purge(&bch->rqueue);
 		bch->rcount = 0;
 		return;
 	}
 	bch->rcount++;
 	skb_queue_tail(&bch->rqueue, bch->rx_skb);
 	bch->rx_skb = NULL;
 	schedule_event(bch, FLG_RECVQUEUE);
 }
 EXPORT_SYMBOL(recv_Bchannel);

 void
 recv_Dchannel_skb(struct dchannel *dch, struct sk_buff *skb)
 {
 	skb_queue_tail(&dch->rqueue, skb);
 	schedule_event(dch, FLG_RECVQUEUE);
 }
 EXPORT_SYMBOL(recv_Dchannel_skb);

 void
 recv_Bchannel_skb(struct bchannel *bch, struct sk_buff *skb)
 {
 	if (bch->rcount >= 64) {
 		printk(KERN_WARNING "B-channel %p receive queue overflow, "
 			"fushing!\n", bch);
 		skb_queue_purge(&bch->rqueue);
 		bch->rcount = 0;
 	}
 	bch->rcount++;
 	skb_queue_tail(&bch->rqueue, skb);
 	schedule_event(bch, FLG_RECVQUEUE);
 }
 EXPORT_SYMBOL(recv_Bchannel_skb);

 static void
 confirm_Dsend(struct dchannel *dch)
 {
 	struct sk_buff	*skb;

 	skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(dch->tx_skb),
 	    0, NULL, GFP_ATOMIC);
 	if (!skb) {
 		printk(KERN_ERR "%s: no skb id %x\n", __func__,
 		    mISDN_HEAD_ID(dch->tx_skb));
 		return;
 	}
 	skb_queue_tail(&dch->rqueue, skb);
 	schedule_event(dch, FLG_RECVQUEUE);
 }

 int
 get_next_dframe(struct dchannel *dch)
 {
 	dch->tx_idx = 0;
 	dch->tx_skb = skb_dequeue(&dch->squeue);
 	if (dch->tx_skb) {
 		confirm_Dsend(dch);
 		return 1;
 	}
 	dch->tx_skb = NULL;
 	test_and_clear_bit(FLG_TX_BUSY, &dch->Flags);
 	return 0;
 }
 EXPORT_SYMBOL(get_next_dframe);

 void
 confirm_Bsend(struct bchannel *bch)
 {
 	struct sk_buff	*skb;

 	if (bch->rcount >= 64) {
 		printk(KERN_WARNING "B-channel %p receive queue overflow, "
 			"fushing!\n", bch);
 		skb_queue_purge(&bch->rqueue);
 		bch->rcount = 0;
 	}
 	skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(bch->tx_skb),
 	    0, NULL, GFP_ATOMIC);
 	if (!skb) {
 		printk(KERN_ERR "%s: no skb id %x\n", __func__,
 		    mISDN_HEAD_ID(bch->tx_skb));
 		return;
 	}
 	bch->rcount++;
 	skb_queue_tail(&bch->rqueue, skb);
 	schedule_event(bch, FLG_RECVQUEUE);
 }
 EXPORT_SYMBOL(confirm_Bsend);

 int
 get_next_bframe(struct bchannel *bch)
 {
 	bch->tx_idx = 0;
 	if (test_bit(FLG_TX_NEXT, &bch->Flags)) {
 		bch->tx_skb = bch->next_skb;
 		if (bch->tx_skb) {
 			bch->next_skb = NULL;
 			test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
 			if (!test_bit(FLG_TRANSPARENT, &bch->Flags))
 				confirm_Bsend(bch); /* not for transparent */
 			return 1;
 		} else {
 			test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
 			printk(KERN_WARNING "B TX_NEXT without skb\n");
 		}
 	}
 	bch->tx_skb = NULL;
 	test_and_clear_bit(FLG_TX_BUSY, &bch->Flags);
 	return 0;
 }
 EXPORT_SYMBOL(get_next_bframe);

 void
 queue_ch_frame(struct mISDNchannel *ch, u_int pr, int id, struct sk_buff *skb)
 {
 	struct mISDNhead *hh;

 	if (!skb) {
 		_queue_data(ch, pr, id, 0, NULL, GFP_ATOMIC);
 	} else {
 		if (ch->peer) {
 			hh = mISDN_HEAD_P(skb);
 			hh->prim = pr;
 			hh->id = id;
 			if (!ch->recv(ch->peer, skb))
 				return;
 		}
 		dev_kfree_skb(skb);
 	}
 }
 EXPORT_SYMBOL(queue_ch_frame);

 int
 dchannel_senddata(struct dchannel *ch, struct sk_buff *skb)
 {
 	/* check oversize */
 	if (skb->len <= 0) {
 		printk(KERN_WARNING "%s: skb too small\n", __func__);
 		return -EINVAL;
 	}
 	if (skb->len > ch->maxlen) {
 		printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
 			__func__, skb->len, ch->maxlen);
 		return -EINVAL;
 	}
 	/* HW lock must be obtained */
 	if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
 		skb_queue_tail(&ch->squeue, skb);
 		return 0;
 	} else {
 		/* write to fifo */
 		ch->tx_skb = skb;
 		ch->tx_idx = 0;
 		return 1;
 	}
 }
 EXPORT_SYMBOL(dchannel_senddata);

 int
 bchannel_senddata(struct bchannel *ch, struct sk_buff *skb)
 {

 	/* check oversize */
 	if (skb->len <= 0) {
 		printk(KERN_WARNING "%s: skb too small\n", __func__);
 		return -EINVAL;
 	}
 	if (skb->len > ch->maxlen) {
 		printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
 			__func__, skb->len, ch->maxlen);
 		return -EINVAL;
 	}
 	/* HW lock must be obtained */
 	/* check for pending next_skb */
 	if (ch->next_skb) {
 		printk(KERN_WARNING
 		    "%s: next_skb exist ERROR (skb->len=%d next_skb->len=%d)\n",
 		    __func__, skb->len, ch->next_skb->len);
 		return -EBUSY;
 	}
 	if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
 		test_and_set_bit(FLG_TX_NEXT, &ch->Flags);
 		ch->next_skb = skb;
 		return 0;
 	} else {
 		/* write to fifo */
 		ch->tx_skb = skb;
 		ch->tx_idx = 0;
 		return 1;
 	}
 }
 EXPORT_SYMBOL(bchannel_senddata);
	/*
	*
	* Author Karsten Keil <kkeil@novell.com>
	*
	* Copyright 2008 by Karsten Keil <kkeil@novell.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	*/

	#include <linux/module.h>
	#include <linux/mISDNhw.h>

	static void
	dchannel_bh(struct work_struct *ws)
	{
	struct dchannel *dch = container_of(ws, struct dchannel, workq);
	struct sk_buff *skb;
	int err;

	if (test_and_clear_bit(FLG_RECVQUEUE, &dch->Flags)) {
	while ((skb = skb_dequeue(&dch->rqueue))) {
	if (likely(dch->dev.D.peer)) {
	err = dch->dev.D.recv(dch->dev.D.peer, skb);
	if (err)
	dev_kfree_skb(skb);
	} else
	dev_kfree_skb(skb);
	}
	}
	if (test_and_clear_bit(FLG_PHCHANGE, &dch->Flags)) {
	if (dch->phfunc)
	dch->phfunc(dch);
	}
	}

	static void
	bchannel_bh(struct work_struct *ws)
	{
	struct bchannel *bch = container_of(ws, struct bchannel, workq);
	struct sk_buff *skb;
	int err;

	if (test_and_clear_bit(FLG_RECVQUEUE, &bch->Flags)) {
	while ((skb = skb_dequeue(&bch->rqueue))) {
	bch->rcount--;
	if (likely(bch->ch.peer)) {
	err = bch->ch.recv(bch->ch.peer, skb);
	if (err)
	dev_kfree_skb(skb);
	} else
	dev_kfree_skb(skb);
	}
	}
	}

	int
	mISDN_initdchannel(struct dchannel ch, int maxlen, void phf)
	{
	test_and_set_bit(FLG_HDLC, &ch->Flags);
	ch->maxlen = maxlen;
	ch->hw = NULL;
	ch->rx_skb = NULL;
	ch->tx_skb = NULL;
	ch->tx_idx = 0;
	ch->phfunc = phf;
	skb_queue_head_init(&ch->squeue);
	skb_queue_head_init(&ch->rqueue);
	INIT_LIST_HEAD(&ch->dev.bchannels);
	INIT_WORK(&ch->workq, dchannel_bh);
	return 0;
	}
	EXPORT_SYMBOL(mISDN_initdchannel);

	int
	mISDN_initbchannel(struct bchannel *ch, int maxlen)
	{
	ch->Flags = 0;
	ch->maxlen = maxlen;
	ch->hw = NULL;
	ch->rx_skb = NULL;
	ch->tx_skb = NULL;
	ch->tx_idx = 0;
	skb_queue_head_init(&ch->rqueue);
	ch->rcount = 0;
	ch->next_skb = NULL;
	INIT_WORK(&ch->workq, bchannel_bh);
	return 0;
	}
	EXPORT_SYMBOL(mISDN_initbchannel);

	int
	mISDN_freedchannel(struct dchannel *ch)
	{
	if (ch->tx_skb) {
	dev_kfree_skb(ch->tx_skb);
	ch->tx_skb = NULL;
	}
	if (ch->rx_skb) {
	dev_kfree_skb(ch->rx_skb);
	ch->rx_skb = NULL;
	}
	skb_queue_purge(&ch->squeue);
	skb_queue_purge(&ch->rqueue);
	flush_scheduled_work();
	return 0;
	}
	EXPORT_SYMBOL(mISDN_freedchannel);

	int
	mISDN_freebchannel(struct bchannel *ch)
	{
	if (ch->tx_skb) {
	dev_kfree_skb(ch->tx_skb);
	ch->tx_skb = NULL;
	}
	if (ch->rx_skb) {
	dev_kfree_skb(ch->rx_skb);
	ch->rx_skb = NULL;
	}
	if (ch->next_skb) {
	dev_kfree_skb(ch->next_skb);
	ch->next_skb = NULL;
	}
	skb_queue_purge(&ch->rqueue);
	ch->rcount = 0;
	flush_scheduled_work();
	return 0;
	}
	EXPORT_SYMBOL(mISDN_freebchannel);

	static inline u_int
	get_sapi_tei(u_char *p)
	{
	u_int sapi, tei;

	sapi = *p >> 2;
	tei = p[1] >> 1;
	return sapi \| (tei << 8);
	}

	void
	recv_Dchannel(struct dchannel *dch)
	{
	struct mISDNhead *hh;

	if (dch->rx_skb->len < 2) { /* at least 2 for sapi / tei */
	dev_kfree_skb(dch->rx_skb);
	dch->rx_skb = NULL;
	return;
	}
	hh = mISDN_HEAD_P(dch->rx_skb);
	hh->prim = PH_DATA_IND;
	hh->id = get_sapi_tei(dch->rx_skb->data);
	skb_queue_tail(&dch->rqueue, dch->rx_skb);
	dch->rx_skb = NULL;
	schedule_event(dch, FLG_RECVQUEUE);
	}
	EXPORT_SYMBOL(recv_Dchannel);

	void
	recv_Echannel(struct dchannel ech, struct dchannel dch)
	{
	struct mISDNhead *hh;

	if (ech->rx_skb->len < 2) { /* at least 2 for sapi / tei */
	dev_kfree_skb(ech->rx_skb);
	ech->rx_skb = NULL;
	return;
	}
	hh = mISDN_HEAD_P(ech->rx_skb);
	hh->prim = PH_DATA_E_IND;
	hh->id = get_sapi_tei(ech->rx_skb->data);
	skb_queue_tail(&dch->rqueue, ech->rx_skb);
	ech->rx_skb = NULL;
	schedule_event(dch, FLG_RECVQUEUE);
	}
	EXPORT_SYMBOL(recv_Echannel);

	void
	recv_Bchannel(struct bchannel *bch, unsigned int id)
	{
	struct mISDNhead *hh;

	hh = mISDN_HEAD_P(bch->rx_skb);
	hh->prim = PH_DATA_IND;
	hh->id = id;
	if (bch->rcount >= 64) {
	printk(KERN_WARNING "B-channel %p receive queue overflow, "
	"fushing!\n", bch);
	skb_queue_purge(&bch->rqueue);
	bch->rcount = 0;
	return;
	}
	bch->rcount++;
	skb_queue_tail(&bch->rqueue, bch->rx_skb);
	bch->rx_skb = NULL;
	schedule_event(bch, FLG_RECVQUEUE);
	}
	EXPORT_SYMBOL(recv_Bchannel);

	void
	recv_Dchannel_skb(struct dchannel dch, struct sk_buff skb)
	{
	skb_queue_tail(&dch->rqueue, skb);
	schedule_event(dch, FLG_RECVQUEUE);
	}
	EXPORT_SYMBOL(recv_Dchannel_skb);

	void
	recv_Bchannel_skb(struct bchannel bch, struct sk_buff skb)
	{
	if (bch->rcount >= 64) {
	printk(KERN_WARNING "B-channel %p receive queue overflow, "
	"fushing!\n", bch);
	skb_queue_purge(&bch->rqueue);
	bch->rcount = 0;
	}
	bch->rcount++;
	skb_queue_tail(&bch->rqueue, skb);
	schedule_event(bch, FLG_RECVQUEUE);
	}
	EXPORT_SYMBOL(recv_Bchannel_skb);

	static void
	confirm_Dsend(struct dchannel *dch)
	{
	struct sk_buff *skb;

	skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(dch->tx_skb),
	0, NULL, GFP_ATOMIC);
	if (!skb) {
	printk(KERN_ERR "%s: no skb id %x\n", __func__,
	mISDN_HEAD_ID(dch->tx_skb));
	return;
	}
	skb_queue_tail(&dch->rqueue, skb);
	schedule_event(dch, FLG_RECVQUEUE);
	}

	int
	get_next_dframe(struct dchannel *dch)
	{
	dch->tx_idx = 0;
	dch->tx_skb = skb_dequeue(&dch->squeue);
	if (dch->tx_skb) {
	confirm_Dsend(dch);
	return 1;
	}
	dch->tx_skb = NULL;
	test_and_clear_bit(FLG_TX_BUSY, &dch->Flags);
	return 0;
	}
	EXPORT_SYMBOL(get_next_dframe);

	void
	confirm_Bsend(struct bchannel *bch)
	{
	struct sk_buff *skb;

	if (bch->rcount >= 64) {
	printk(KERN_WARNING "B-channel %p receive queue overflow, "
	"fushing!\n", bch);
	skb_queue_purge(&bch->rqueue);
	bch->rcount = 0;
	}
	skb = _alloc_mISDN_skb(PH_DATA_CNF, mISDN_HEAD_ID(bch->tx_skb),
	0, NULL, GFP_ATOMIC);
	if (!skb) {
	printk(KERN_ERR "%s: no skb id %x\n", __func__,
	mISDN_HEAD_ID(bch->tx_skb));
	return;
	}
	bch->rcount++;
	skb_queue_tail(&bch->rqueue, skb);
	schedule_event(bch, FLG_RECVQUEUE);
	}
	EXPORT_SYMBOL(confirm_Bsend);

	int
	get_next_bframe(struct bchannel *bch)
	{
	bch->tx_idx = 0;
	if (test_bit(FLG_TX_NEXT, &bch->Flags)) {
	bch->tx_skb = bch->next_skb;
	if (bch->tx_skb) {
	bch->next_skb = NULL;
	test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
	if (!test_bit(FLG_TRANSPARENT, &bch->Flags))
	confirm_Bsend(bch); /* not for transparent */
	return 1;
	} else {
	test_and_clear_bit(FLG_TX_NEXT, &bch->Flags);
	printk(KERN_WARNING "B TX_NEXT without skb\n");
	}
	}
	bch->tx_skb = NULL;
	test_and_clear_bit(FLG_TX_BUSY, &bch->Flags);
	return 0;
	}
	EXPORT_SYMBOL(get_next_bframe);

	void
	queue_ch_frame(struct mISDNchannel ch, u_int pr, int id, struct sk_buff skb)
	{
	struct mISDNhead *hh;

	if (!skb) {
	_queue_data(ch, pr, id, 0, NULL, GFP_ATOMIC);
	} else {
	if (ch->peer) {
	hh = mISDN_HEAD_P(skb);
	hh->prim = pr;
	hh->id = id;
	if (!ch->recv(ch->peer, skb))
	return;
	}
	dev_kfree_skb(skb);
	}
	}
	EXPORT_SYMBOL(queue_ch_frame);

	int
	dchannel_senddata(struct dchannel ch, struct sk_buff skb)
	{
	/* check oversize */
	if (skb->len <= 0) {
	printk(KERN_WARNING "%s: skb too small\n", __func__);
	return -EINVAL;
	}
	if (skb->len > ch->maxlen) {
	printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
	__func__, skb->len, ch->maxlen);
	return -EINVAL;
	}
	/* HW lock must be obtained */
	if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
	skb_queue_tail(&ch->squeue, skb);
	return 0;
	} else {
	/* write to fifo */
	ch->tx_skb = skb;
	ch->tx_idx = 0;
	return 1;
	}
	}
	EXPORT_SYMBOL(dchannel_senddata);

	int
	bchannel_senddata(struct bchannel ch, struct sk_buff skb)
	{

	/* check oversize */
	if (skb->len <= 0) {
	printk(KERN_WARNING "%s: skb too small\n", __func__);
	return -EINVAL;
	}
	if (skb->len > ch->maxlen) {
	printk(KERN_WARNING "%s: skb too large(%d/%d)\n",
	__func__, skb->len, ch->maxlen);
	return -EINVAL;
	}
	/* HW lock must be obtained */
	/* check for pending next_skb */
	if (ch->next_skb) {
	printk(KERN_WARNING
	"%s: next_skb exist ERROR (skb->len=%d next_skb->len=%d)\n",
	__func__, skb->len, ch->next_skb->len);
	return -EBUSY;
	}
	if (test_and_set_bit(FLG_TX_BUSY, &ch->Flags)) {
	test_and_set_bit(FLG_TX_NEXT, &ch->Flags);
	ch->next_skb = skb;
	return 0;
	} else {
	/* write to fifo */
	ch->tx_skb = skb;
	ch->tx_idx = 0;
	return 1;
	}
	}
	EXPORT_SYMBOL(bchannel_senddata);