1 files changed, 643 insertions, 0 deletions

diff --git a/drivers/s390/net/qeth_eddp.c b/drivers/s390/net/qeth_eddp.c
new file mode 100644
index 000000000000..7ee1c06ed68a
--- /dev/null
+++ b/drivers/s390/net/qeth_eddp.c
@@ -0,0 +1,643 @@
+/*
+ *
+ * linux/drivers/s390/net/qeth_eddp.c ($Revision: 1.11 $)
+ *
+ * Enhanced Device Driver Packing (EDDP) support for the qeth driver.
+ *
+ * Copyright 2004 IBM Corporation
+ *
+ *    Author(s): Thomas Spatzier <tspat@de.ibm.com>
+ *
+ *    $Revision: 1.11 $	 $Date: 2005/03/24 09:04:18 $
+ *
+ */
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/ip.h>
+#include <linux/inetdevice.h>
+#include <linux/netdevice.h>
+#include <linux/kernel.h>
+#include <linux/tcp.h>
+#include <net/tcp.h>
+#include <linux/skbuff.h>
+
+#include <net/ip.h>
+
+#include "qeth.h"
+#include "qeth_mpc.h"
+#include "qeth_eddp.h"
+
+int
+qeth_eddp_check_buffers_for_context(struct qeth_qdio_out_q *queue,
+				    struct qeth_eddp_context *ctx)
+{
+	int index = queue->next_buf_to_fill;
+	int elements_needed = ctx->num_elements;
+	int elements_in_buffer;
+	int skbs_in_buffer;
+	int buffers_needed = 0;
+
+	QETH_DBF_TEXT(trace, 5, "eddpcbfc");
+	while(elements_needed > 0) {
+		buffers_needed++;
+		if (atomic_read(&queue->bufs[index].state) !=
+				QETH_QDIO_BUF_EMPTY)
+			return -EBUSY;
+
+		elements_in_buffer = QETH_MAX_BUFFER_ELEMENTS(queue->card) -
+				     queue->bufs[index].next_element_to_fill;
+		skbs_in_buffer = elements_in_buffer / ctx->elements_per_skb;
+		elements_needed -= skbs_in_buffer * ctx->elements_per_skb;
+		index = (index + 1) % QDIO_MAX_BUFFERS_PER_Q;
+	}
+	return buffers_needed;
+}
+
+static inline void
+qeth_eddp_free_context(struct qeth_eddp_context *ctx)
+{
+	int i;
+
+	QETH_DBF_TEXT(trace, 5, "eddpfctx");
+	for (i = 0; i < ctx->num_pages; ++i)
+		free_page((unsigned long)ctx->pages[i]);
+	kfree(ctx->pages);
+	if (ctx->elements != NULL)
+		kfree(ctx->elements);
+	kfree(ctx);
+}
+
+
+static inline void
+qeth_eddp_get_context(struct qeth_eddp_context *ctx)
+{
+	atomic_inc(&ctx->refcnt);
+}
+
+void
+qeth_eddp_put_context(struct qeth_eddp_context *ctx)
+{
+	if (atomic_dec_return(&ctx->refcnt) == 0)
+		qeth_eddp_free_context(ctx);
+}
+
+void
+qeth_eddp_buf_release_contexts(struct qeth_qdio_out_buffer *buf)
+{
+	struct qeth_eddp_context_reference *ref;
+
+	QETH_DBF_TEXT(trace, 6, "eddprctx");
+	while (!list_empty(&buf->ctx_list)){
+		ref = list_entry(buf->ctx_list.next,
+				 struct qeth_eddp_context_reference, list);
+		qeth_eddp_put_context(ref->ctx);
+		list_del(&ref->list);
+		kfree(ref);
+	}
+}
+
+static inline int
+qeth_eddp_buf_ref_context(struct qeth_qdio_out_buffer *buf,
+			  struct qeth_eddp_context *ctx)
+{
+	struct qeth_eddp_context_reference *ref;
+
+	QETH_DBF_TEXT(trace, 6, "eddprfcx");
+	ref = kmalloc(sizeof(struct qeth_eddp_context_reference), GFP_ATOMIC);
+	if (ref == NULL)
+		return -ENOMEM;
+	qeth_eddp_get_context(ctx);
+	ref->ctx = ctx;
+	list_add_tail(&ref->list, &buf->ctx_list);
+	return 0;
+}
+
+int
+qeth_eddp_fill_buffer(struct qeth_qdio_out_q *queue,
+		      struct qeth_eddp_context *ctx,
+		      int index)
+{
+	struct qeth_qdio_out_buffer *buf = NULL;
+	struct qdio_buffer *buffer;
+	int elements = ctx->num_elements;
+	int element = 0;
+	int flush_cnt = 0;
+	int must_refcnt = 1;
+	int i;
+
+	QETH_DBF_TEXT(trace, 5, "eddpfibu");
+	while (elements > 0) {
+		buf = &queue->bufs[index];
+		if (atomic_read(&buf->state) != QETH_QDIO_BUF_EMPTY){
+			/* normally this should not happen since we checked for
+			 * available elements in qeth_check_elements_for_context
+			 */
+			if (element == 0)
+				return -EBUSY;
+			else {
+				PRINT_WARN("could only partially fill eddp "
+					   "buffer!\n");
+				goto out;
+			}
+		}
+		/* check if the whole next skb fits into current buffer */
+		if ((QETH_MAX_BUFFER_ELEMENTS(queue->card) -
+					buf->next_element_to_fill)
+				< ctx->elements_per_skb){
+			/* no -> go to next buffer */
+			atomic_set(&buf->state, QETH_QDIO_BUF_PRIMED);
+			index = (index + 1) % QDIO_MAX_BUFFERS_PER_Q;
+			flush_cnt++;
+			/* new buffer, so we have to add ctx to buffer'ctx_list
+			 * and increment ctx's refcnt */
+			must_refcnt = 1;
+			continue;
+		}
+		if (must_refcnt){
+			must_refcnt = 0;
+			if (qeth_eddp_buf_ref_context(buf, ctx)){
+				PRINT_WARN("no memory to create eddp context "
+					   "reference\n");
+				goto out_check;
+			}
+		}
+		buffer = buf->buffer;
+		/* fill one skb into buffer */
+		for (i = 0; i < ctx->elements_per_skb; ++i){
+			buffer->element[buf->next_element_to_fill].addr =
+				ctx->elements[element].addr;
+			buffer->element[buf->next_element_to_fill].length =
+				ctx->elements[element].length;
+			buffer->element[buf->next_element_to_fill].flags =
+				ctx->elements[element].flags;
+			buf->next_element_to_fill++;
+			element++;
+			elements--;
+		}
+	}
+out_check:
+	if (!queue->do_pack) {
+		QETH_DBF_TEXT(trace, 6, "fillbfnp");
+		/* set state to PRIMED -> will be flushed */
+		if (buf->next_element_to_fill > 0){
+			atomic_set(&buf->state, QETH_QDIO_BUF_PRIMED);
+			flush_cnt++;
+		}
+	} else {
+#ifdef CONFIG_QETH_PERF_STATS
+		queue->card->perf_stats.skbs_sent_pack++;
+#endif
+		QETH_DBF_TEXT(trace, 6, "fillbfpa");
+		if (buf->next_element_to_fill >=
+				QETH_MAX_BUFFER_ELEMENTS(queue->card)) {
+			/*
+			 * packed buffer if full -> set state PRIMED
+			 * -> will be flushed
+			 */
+			atomic_set(&buf->state, QETH_QDIO_BUF_PRIMED);
+			flush_cnt++;
+		}
+	}
+out:
+	return flush_cnt;
+}
+
+static inline int
+qeth_get_skb_data_len(struct sk_buff *skb)
+{
+	int len = skb->len;
+	int i;
+
+	for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i)
+		len -= skb_shinfo(skb)->frags[i].size;
+	return len;
+}
+
+static inline void
+qeth_eddp_create_segment_hdrs(struct qeth_eddp_context *ctx,
+			      struct qeth_eddp_data *eddp)
+{
+	u8 *page;
+	int page_remainder;
+	int page_offset;
+	int hdr_len;
+	struct qeth_eddp_element *element;
+
+	QETH_DBF_TEXT(trace, 5, "eddpcrsh");
+	page = ctx->pages[ctx->offset >> PAGE_SHIFT];
+	page_offset = ctx->offset % PAGE_SIZE;
+	element = &ctx->elements[ctx->num_elements];
+	hdr_len = eddp->nhl + eddp->thl;
+	/* FIXME: layer2 and VLAN !!! */
+	if (eddp->qh.hdr.l2.id == QETH_HEADER_TYPE_LAYER2)
+		hdr_len += ETH_HLEN;
+	if (eddp->mac.h_proto == __constant_htons(ETH_P_8021Q))
+		hdr_len += VLAN_HLEN;
+	/* does complete header fit in current page ? */
+	page_remainder = PAGE_SIZE - page_offset;
+	if (page_remainder < (sizeof(struct qeth_hdr) + hdr_len)){
+		/* no -> go to start of next page */
+		ctx->offset += page_remainder;
+		page = ctx->pages[ctx->offset >> PAGE_SHIFT];
+		page_offset = 0;
+	}
+	memcpy(page + page_offset, &eddp->qh, sizeof(struct qeth_hdr));
+	element->addr = page + page_offset;
+	element->length = sizeof(struct qeth_hdr);
+	ctx->offset += sizeof(struct qeth_hdr);
+	page_offset += sizeof(struct qeth_hdr);
+	/* add mac header (?) */
+	if (eddp->qh.hdr.l2.id == QETH_HEADER_TYPE_LAYER2){
+		memcpy(page + page_offset, &eddp->mac, ETH_HLEN);
+		element->length += ETH_HLEN;
+		ctx->offset += ETH_HLEN;
+		page_offset += ETH_HLEN;
+	}
+	/* add VLAN tag */
+	if (eddp->mac.h_proto == __constant_htons(ETH_P_8021Q)){
+		memcpy(page + page_offset, &eddp->vlan, VLAN_HLEN);
+		element->length += VLAN_HLEN;
+		ctx->offset += VLAN_HLEN;
+		page_offset += VLAN_HLEN;
+	}
+	/* add network header */
+	memcpy(page + page_offset, (u8 *)&eddp->nh, eddp->nhl);
+	element->length += eddp->nhl;
+	eddp->nh_in_ctx = page + page_offset;
+	ctx->offset += eddp->nhl;
+	page_offset += eddp->nhl;
+	/* add transport header */
+	memcpy(page + page_offset, (u8 *)&eddp->th, eddp->thl);
+	element->length += eddp->thl;
+	eddp->th_in_ctx = page + page_offset;
+	ctx->offset += eddp->thl;
+}
+
+static inline void
+qeth_eddp_copy_data_tcp(char *dst, struct qeth_eddp_data *eddp, int len,
+			u32 *hcsum)
+{
+	struct skb_frag_struct *frag;
+	int left_in_frag;
+	int copy_len;
+	u8 *src;
+
+	QETH_DBF_TEXT(trace, 5, "eddpcdtc");
+	if (skb_shinfo(eddp->skb)->nr_frags == 0) {
+		memcpy(dst, eddp->skb->data + eddp->skb_offset, len);
+		*hcsum = csum_partial(eddp->skb->data + eddp->skb_offset, len,
+				      *hcsum);
+		eddp->skb_offset += len;
+	} else {
+		while (len > 0) {
+			if (eddp->frag < 0) {
+				/* we're in skb->data */
+				left_in_frag = qeth_get_skb_data_len(eddp->skb)
+						- eddp->skb_offset;
+				src = eddp->skb->data + eddp->skb_offset;
+			} else {
+				frag = &skb_shinfo(eddp->skb)->
+					frags[eddp->frag];
+				left_in_frag = frag->size - eddp->frag_offset;
+				src = (u8 *)(
+					(page_to_pfn(frag->page) << PAGE_SHIFT)+
+					frag->page_offset + eddp->frag_offset);
+			}
+			if (left_in_frag <= 0) {
+				eddp->frag++;
+				eddp->frag_offset = 0;
+				continue;
+			}
+			copy_len = min(left_in_frag, len);
+			memcpy(dst, src, copy_len);
+			*hcsum = csum_partial(src, copy_len, *hcsum);
+			dst += copy_len;
+			eddp->frag_offset += copy_len;
+			eddp->skb_offset += copy_len;
+			len -= copy_len;
+		}
+	}
+}
+
+static inline void
+qeth_eddp_create_segment_data_tcp(struct qeth_eddp_context *ctx,
+				  struct qeth_eddp_data *eddp, int data_len,
+				  u32 hcsum)
+{
+	u8 *page;
+	int page_remainder;
+	int page_offset;
+	struct qeth_eddp_element *element;
+	int first_lap = 1;
+
+	QETH_DBF_TEXT(trace, 5, "eddpcsdt");
+	page = ctx->pages[ctx->offset >> PAGE_SHIFT];
+	page_offset = ctx->offset % PAGE_SIZE;
+	element = &ctx->elements[ctx->num_elements];
+	while (data_len){
+		page_remainder = PAGE_SIZE - page_offset;
+		if (page_remainder < data_len){
+			qeth_eddp_copy_data_tcp(page + page_offset, eddp,
+						page_remainder, &hcsum);
+			element->length += page_remainder;
+			if (first_lap)
+				element->flags = SBAL_FLAGS_FIRST_FRAG;
+			else
+				element->flags = SBAL_FLAGS_MIDDLE_FRAG;
+			ctx->num_elements++;
+			element++;
+			data_len -= page_remainder;
+			ctx->offset += page_remainder;
+			page = ctx->pages[ctx->offset >> PAGE_SHIFT];
+			page_offset = 0;
+			element->addr = page + page_offset;
+		} else {
+			qeth_eddp_copy_data_tcp(page + page_offset, eddp,
+						data_len, &hcsum);
+			element->length += data_len;
+			if (!first_lap)
+				element->flags = SBAL_FLAGS_LAST_FRAG;
+			ctx->num_elements++;
+			ctx->offset += data_len;
+			data_len = 0;
+		}
+		first_lap = 0;
+	}
+	((struct tcphdr *)eddp->th_in_ctx)->check = csum_fold(hcsum);
+}
+
+static inline u32
+qeth_eddp_check_tcp4_hdr(struct qeth_eddp_data *eddp, int data_len)
+{
+	u32 phcsum; /* pseudo header checksum */
+
+	QETH_DBF_TEXT(trace, 5, "eddpckt4");
+	eddp->th.tcp.h.check = 0;
+	/* compute pseudo header checksum */
+	phcsum = csum_tcpudp_nofold(eddp->nh.ip4.h.saddr, eddp->nh.ip4.h.daddr,
+				    eddp->thl + data_len, IPPROTO_TCP, 0);
+	/* compute checksum of tcp header */
+	return csum_partial((u8 *)&eddp->th, eddp->thl, phcsum);
+}
+
+static inline u32
+qeth_eddp_check_tcp6_hdr(struct qeth_eddp_data *eddp, int data_len)
+{
+	u32 proto;
+	u32 phcsum; /* pseudo header checksum */
+
+	QETH_DBF_TEXT(trace, 5, "eddpckt6");
+	eddp->th.tcp.h.check = 0;
+	/* compute pseudo header checksum */
+	phcsum = csum_partial((u8 *)&eddp->nh.ip6.h.saddr,
+			      sizeof(struct in6_addr), 0);
+	phcsum = csum_partial((u8 *)&eddp->nh.ip6.h.daddr,
+			      sizeof(struct in6_addr), phcsum);
+	proto = htonl(IPPROTO_TCP);
+	phcsum = csum_partial((u8 *)&proto, sizeof(u32), phcsum);
+	return phcsum;
+}
+
+static inline struct qeth_eddp_data *
+qeth_eddp_create_eddp_data(struct qeth_hdr *qh, u8 *nh, u8 nhl, u8 *th, u8 thl)
+{
+	struct qeth_eddp_data *eddp;
+
+	QETH_DBF_TEXT(trace, 5, "eddpcrda");
+	eddp = kmalloc(sizeof(struct qeth_eddp_data), GFP_ATOMIC);
+	if (eddp){
+		memset(eddp, 0, sizeof(struct qeth_eddp_data));
+		eddp->nhl = nhl;
+		eddp->thl = thl;
+		memcpy(&eddp->qh, qh, sizeof(struct qeth_hdr));
+		memcpy(&eddp->nh, nh, nhl);
+		memcpy(&eddp->th, th, thl);
+		eddp->frag = -1; /* initially we're in skb->data */
+	}
+	return eddp;
+}
+
+static inline void
+__qeth_eddp_fill_context_tcp(struct qeth_eddp_context *ctx,
+			     struct qeth_eddp_data *eddp)
+{
+	struct tcphdr *tcph;
+	int data_len;
+	u32 hcsum;
+
+	QETH_DBF_TEXT(trace, 5, "eddpftcp");
+	eddp->skb_offset = sizeof(struct qeth_hdr) + eddp->nhl + eddp->thl;
+	tcph = eddp->skb->h.th;
+	while (eddp->skb_offset < eddp->skb->len) {
+		data_len = min((int)skb_shinfo(eddp->skb)->tso_size,
+			       (int)(eddp->skb->len - eddp->skb_offset));
+		/* prepare qdio hdr */
+		if (eddp->qh.hdr.l2.id == QETH_HEADER_TYPE_LAYER2){
+			eddp->qh.hdr.l2.pkt_length = data_len + ETH_HLEN +
+						     eddp->nhl + eddp->thl -
+						     sizeof(struct qeth_hdr);
+#ifdef CONFIG_QETH_VLAN
+			if (eddp->mac.h_proto == __constant_htons(ETH_P_8021Q))
+				eddp->qh.hdr.l2.pkt_length += VLAN_HLEN;
+#endif /* CONFIG_QETH_VLAN */
+		} else
+			eddp->qh.hdr.l3.length = data_len + eddp->nhl +
+						 eddp->thl;
+		/* prepare ip hdr */
+		if (eddp->skb->protocol == ETH_P_IP){
+			eddp->nh.ip4.h.tot_len = data_len + eddp->nhl +
+						 eddp->thl;
+			eddp->nh.ip4.h.check = 0;
+			eddp->nh.ip4.h.check =
+				ip_fast_csum((u8 *)&eddp->nh.ip4.h,
+						eddp->nh.ip4.h.ihl);
+		} else
+			eddp->nh.ip6.h.payload_len = data_len + eddp->thl;
+		/* prepare tcp hdr */
+		if (data_len == (eddp->skb->len - eddp->skb_offset)){
+			/* last segment -> set FIN and PSH flags */
+			eddp->th.tcp.h.fin = tcph->fin;
+			eddp->th.tcp.h.psh = tcph->psh;
+		}
+		if (eddp->skb->protocol == ETH_P_IP)
+			hcsum = qeth_eddp_check_tcp4_hdr(eddp, data_len);
+		else
+			hcsum = qeth_eddp_check_tcp6_hdr(eddp, data_len);
+		/* fill the next segment into the context */
+		qeth_eddp_create_segment_hdrs(ctx, eddp);
+		qeth_eddp_create_segment_data_tcp(ctx, eddp, data_len, hcsum);
+		if (eddp->skb_offset >= eddp->skb->len)
+			break;
+		/* prepare headers for next round */
+		if (eddp->skb->protocol == ETH_P_IP)
+			eddp->nh.ip4.h.id++;
+		eddp->th.tcp.h.seq += data_len;
+	}
+}
+
+static inline int
+qeth_eddp_fill_context_tcp(struct qeth_eddp_context *ctx,
+			   struct sk_buff *skb, struct qeth_hdr *qhdr)
+{
+	struct qeth_eddp_data *eddp = NULL;
+
+	QETH_DBF_TEXT(trace, 5, "eddpficx");
+	/* create our segmentation headers and copy original headers */
+	if (skb->protocol == ETH_P_IP)
+		eddp = qeth_eddp_create_eddp_data(qhdr, (u8 *)skb->nh.iph,
+				skb->nh.iph->ihl*4,
+				(u8 *)skb->h.th, skb->h.th->doff*4);
+	else
+		eddp = qeth_eddp_create_eddp_data(qhdr, (u8 *)skb->nh.ipv6h,
+				sizeof(struct ipv6hdr),
+				(u8 *)skb->h.th, skb->h.th->doff*4);
+
+	if (eddp == NULL) {
+		QETH_DBF_TEXT(trace, 2, "eddpfcnm");
+		return -ENOMEM;
+	}
+	if (qhdr->hdr.l2.id == QETH_HEADER_TYPE_LAYER2) {
+		memcpy(&eddp->mac, eth_hdr(skb), ETH_HLEN);
+#ifdef CONFIG_QETH_VLAN
+		if (eddp->mac.h_proto == __constant_htons(ETH_P_8021Q)) {
+			eddp->vlan[0] = __constant_htons(skb->protocol);
+			eddp->vlan[1] = htons(vlan_tx_tag_get(skb));
+		}
+#endif /* CONFIG_QETH_VLAN */
+	}
+	/* the next flags will only be set on the last segment */
+	eddp->th.tcp.h.fin = 0;
+	eddp->th.tcp.h.psh = 0;
+	eddp->skb = skb;
+	/* begin segmentation and fill context */
+	__qeth_eddp_fill_context_tcp(ctx, eddp);
+	kfree(eddp);
+	return 0;
+}
+
+static inline void
+qeth_eddp_calc_num_pages(struct qeth_eddp_context *ctx, struct sk_buff *skb,
+			 int hdr_len)
+{
+	int skbs_per_page;
+
+	QETH_DBF_TEXT(trace, 5, "eddpcanp");
+	/* can we put multiple skbs in one page? */
+	skbs_per_page = PAGE_SIZE / (skb_shinfo(skb)->tso_size + hdr_len);
+	if (skbs_per_page > 1){
+		ctx->num_pages = (skb_shinfo(skb)->tso_segs + 1) /
+				 skbs_per_page + 1;
+		ctx->elements_per_skb = 1;
+	} else {
+		/* no -> how many elements per skb? */
+		ctx->elements_per_skb = (skb_shinfo(skb)->tso_size + hdr_len +
+				     PAGE_SIZE) >> PAGE_SHIFT;
+		ctx->num_pages = ctx->elements_per_skb *
+				 (skb_shinfo(skb)->tso_segs + 1);
+	}
+	ctx->num_elements = ctx->elements_per_skb *
+			    (skb_shinfo(skb)->tso_segs + 1);
+}
+
+static inline struct qeth_eddp_context *
+qeth_eddp_create_context_generic(struct qeth_card *card, struct sk_buff *skb,
+				 int hdr_len)
+{
+	struct qeth_eddp_context *ctx = NULL;
+	u8 *addr;
+	int i;
+
+	QETH_DBF_TEXT(trace, 5, "creddpcg");
+	/* create the context and allocate pages */
+	ctx = kmalloc(sizeof(struct qeth_eddp_context), GFP_ATOMIC);
+	if (ctx == NULL){
+		QETH_DBF_TEXT(trace, 2, "ceddpcn1");
+		return NULL;
+	}
+	memset(ctx, 0, sizeof(struct qeth_eddp_context));
+	ctx->type = QETH_LARGE_SEND_EDDP;
+	qeth_eddp_calc_num_pages(ctx, skb, hdr_len);
+	if (ctx->elements_per_skb > QETH_MAX_BUFFER_ELEMENTS(card)){
+		QETH_DBF_TEXT(trace, 2, "ceddpcis");
+		kfree(ctx);
+		return NULL;
+	}
+	ctx->pages = kmalloc(ctx->num_pages * sizeof(u8 *), GFP_ATOMIC);
+	if (ctx->pages == NULL){
+		QETH_DBF_TEXT(trace, 2, "ceddpcn2");
+		kfree(ctx);
+		return NULL;
+	}
+	memset(ctx->pages, 0, ctx->num_pages * sizeof(u8 *));
+	for (i = 0; i < ctx->num_pages; ++i){
+		addr = (u8 *)__get_free_page(GFP_ATOMIC);
+		if (addr == NULL){
+			QETH_DBF_TEXT(trace, 2, "ceddpcn3");
+			ctx->num_pages = i;
+			qeth_eddp_free_context(ctx);
+			return NULL;
+		}
+		memset(addr, 0, PAGE_SIZE);
+		ctx->pages[i] = addr;
+	}
+	ctx->elements = kmalloc(ctx->num_elements *
+				sizeof(struct qeth_eddp_element), GFP_ATOMIC);
+	if (ctx->elements == NULL){
+		QETH_DBF_TEXT(trace, 2, "ceddpcn4");
+		qeth_eddp_free_context(ctx);
+		return NULL;
+	}
+	memset(ctx->elements, 0,
+	       ctx->num_elements * sizeof(struct qeth_eddp_element));
+	/* reset num_elements; will be incremented again in fill_buffer to
+	 * reflect number of actually used elements */
+	ctx->num_elements = 0;
+	return ctx;
+}
+
+static inline struct qeth_eddp_context *
+qeth_eddp_create_context_tcp(struct qeth_card *card, struct sk_buff *skb,
+			     struct qeth_hdr *qhdr)
+{
+	struct qeth_eddp_context *ctx = NULL;
+
+	QETH_DBF_TEXT(trace, 5, "creddpct");
+	if (skb->protocol == ETH_P_IP)
+		ctx = qeth_eddp_create_context_generic(card, skb,
+			sizeof(struct qeth_hdr) + skb->nh.iph->ihl*4 +
+			skb->h.th->doff*4);
+	else if (skb->protocol == ETH_P_IPV6)
+		ctx = qeth_eddp_create_context_generic(card, skb,
+			sizeof(struct qeth_hdr) + sizeof(struct ipv6hdr) +
+			skb->h.th->doff*4);
+	else
+		QETH_DBF_TEXT(trace, 2, "cetcpinv");
+
+	if (ctx == NULL) {
+		QETH_DBF_TEXT(trace, 2, "creddpnl");
+		return NULL;
+	}
+	if (qeth_eddp_fill_context_tcp(ctx, skb, qhdr)){
+		QETH_DBF_TEXT(trace, 2, "ceddptfe");
+		qeth_eddp_free_context(ctx);
+		return NULL;
+	}
+	atomic_set(&ctx->refcnt, 1);
+	return ctx;
+}
+
+struct qeth_eddp_context *
+qeth_eddp_create_context(struct qeth_card *card, struct sk_buff *skb,
+			 struct qeth_hdr *qhdr)
+{
+	QETH_DBF_TEXT(trace, 5, "creddpc");
+	switch (skb->sk->sk_protocol){
+	case IPPROTO_TCP:
+		return qeth_eddp_create_context_tcp(card, skb, qhdr);
+	default:
+		QETH_DBF_TEXT(trace, 2, "eddpinvp");
+	}
+	return NULL;
+}
+
+