1/*
2 * AMD 10Gb Ethernet driver
3 *
4 * This file is available to you under your choice of the following two
5 * licenses:
6 *
7 * License 1: GPLv2
8 *
9 * Copyright (c) 2014 Advanced Micro Devices, Inc.
10 *
11 * This file is free software; you may copy, redistribute and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation, either version 2 of the License, or (at
14 * your option) any later version.
15 *
16 * This file is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
23 *
24 * This file incorporates work covered by the following copyright and
25 * permission notice:
26 *     The Synopsys DWC ETHER XGMAC Software Driver and documentation
27 *     (hereinafter "Software") is an unsupported proprietary work of Synopsys,
28 *     Inc. unless otherwise expressly agreed to in writing between Synopsys
29 *     and you.
30 *
31 *     The Software IS NOT an item of Licensed Software or Licensed Product
32 *     under any End User Software License Agreement or Agreement for Licensed
33 *     Product with Synopsys or any supplement thereto.  Permission is hereby
34 *     granted, free of charge, to any person obtaining a copy of this software
35 *     annotated with this license and the Software, to deal in the Software
36 *     without restriction, including without limitation the rights to use,
37 *     copy, modify, merge, publish, distribute, sublicense, and/or sell copies
38 *     of the Software, and to permit persons to whom the Software is furnished
39 *     to do so, subject to the following conditions:
40 *
41 *     The above copyright notice and this permission notice shall be included
42 *     in all copies or substantial portions of the Software.
43 *
44 *     THIS SOFTWARE IS BEING DISTRIBUTED BY SYNOPSYS SOLELY ON AN "AS IS"
45 *     BASIS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
46 *     TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
47 *     PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. IN NO EVENT SHALL SYNOPSYS
48 *     BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
49 *     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
50 *     SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
51 *     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
52 *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
53 *     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
54 *     THE POSSIBILITY OF SUCH DAMAGE.
55 *
56 *
57 * License 2: Modified BSD
58 *
59 * Copyright (c) 2014 Advanced Micro Devices, Inc.
60 * All rights reserved.
61 *
62 * Redistribution and use in source and binary forms, with or without
63 * modification, are permitted provided that the following conditions are met:
64 *     * Redistributions of source code must retain the above copyright
65 *       notice, this list of conditions and the following disclaimer.
66 *     * Redistributions in binary form must reproduce the above copyright
67 *       notice, this list of conditions and the following disclaimer in the
68 *       documentation and/or other materials provided with the distribution.
69 *     * Neither the name of Advanced Micro Devices, Inc. nor the
70 *       names of its contributors may be used to endorse or promote products
71 *       derived from this software without specific prior written permission.
72 *
73 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
74 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
75 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
76 * ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
77 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
78 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
79 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
80 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
81 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
82 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
83 *
84 * This file incorporates work covered by the following copyright and
85 * permission notice:
86 *     The Synopsys DWC ETHER XGMAC Software Driver and documentation
87 *     (hereinafter "Software") is an unsupported proprietary work of Synopsys,
88 *     Inc. unless otherwise expressly agreed to in writing between Synopsys
89 *     and you.
90 *
91 *     The Software IS NOT an item of Licensed Software or Licensed Product
92 *     under any End User Software License Agreement or Agreement for Licensed
93 *     Product with Synopsys or any supplement thereto.  Permission is hereby
94 *     granted, free of charge, to any person obtaining a copy of this software
95 *     annotated with this license and the Software, to deal in the Software
96 *     without restriction, including without limitation the rights to use,
97 *     copy, modify, merge, publish, distribute, sublicense, and/or sell copies
98 *     of the Software, and to permit persons to whom the Software is furnished
99 *     to do so, subject to the following conditions:
100 *
101 *     The above copyright notice and this permission notice shall be included
102 *     in all copies or substantial portions of the Software.
103 *
104 *     THIS SOFTWARE IS BEING DISTRIBUTED BY SYNOPSYS SOLELY ON AN "AS IS"
105 *     BASIS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
106 *     TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
107 *     PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. IN NO EVENT SHALL SYNOPSYS
108 *     BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
109 *     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
110 *     SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
111 *     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
112 *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
113 *     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
114 *     THE POSSIBILITY OF SUCH DAMAGE.
115 */
116
117#include "xgbe.h"
118#include "xgbe-common.h"
119
120static void xgbe_unmap_rdata(struct xgbe_prv_data *, struct xgbe_ring_data *);
121
122static void xgbe_free_ring(struct xgbe_prv_data *pdata,
123			   struct xgbe_ring *ring)
124{
125	struct xgbe_ring_data *rdata;
126	unsigned int i;
127
128	if (!ring)
129		return;
130
131	if (ring->rdata) {
132		for (i = 0; i < ring->rdesc_count; i++) {
133			rdata = XGBE_GET_DESC_DATA(ring, i);
134			xgbe_unmap_rdata(pdata, rdata);
135		}
136
137		kfree(ring->rdata);
138		ring->rdata = NULL;
139	}
140
141	if (ring->rx_hdr_pa.pages) {
142		dma_unmap_page(pdata->dev, ring->rx_hdr_pa.pages_dma,
143			       ring->rx_hdr_pa.pages_len, DMA_FROM_DEVICE);
144		put_page(ring->rx_hdr_pa.pages);
145
146		ring->rx_hdr_pa.pages = NULL;
147		ring->rx_hdr_pa.pages_len = 0;
148		ring->rx_hdr_pa.pages_offset = 0;
149		ring->rx_hdr_pa.pages_dma = 0;
150	}
151
152	if (ring->rx_buf_pa.pages) {
153		dma_unmap_page(pdata->dev, ring->rx_buf_pa.pages_dma,
154			       ring->rx_buf_pa.pages_len, DMA_FROM_DEVICE);
155		put_page(ring->rx_buf_pa.pages);
156
157		ring->rx_buf_pa.pages = NULL;
158		ring->rx_buf_pa.pages_len = 0;
159		ring->rx_buf_pa.pages_offset = 0;
160		ring->rx_buf_pa.pages_dma = 0;
161	}
162
163	if (ring->rdesc) {
164		dma_free_coherent(pdata->dev,
165				  (sizeof(struct xgbe_ring_desc) *
166				   ring->rdesc_count),
167				  ring->rdesc, ring->rdesc_dma);
168		ring->rdesc = NULL;
169	}
170}
171
172static void xgbe_free_ring_resources(struct xgbe_prv_data *pdata)
173{
174	struct xgbe_channel *channel;
175	unsigned int i;
176
177	DBGPR("-->xgbe_free_ring_resources\n");
178
179	channel = pdata->channel;
180	for (i = 0; i < pdata->channel_count; i++, channel++) {
181		xgbe_free_ring(pdata, channel->tx_ring);
182		xgbe_free_ring(pdata, channel->rx_ring);
183	}
184
185	DBGPR("<--xgbe_free_ring_resources\n");
186}
187
188static int xgbe_init_ring(struct xgbe_prv_data *pdata,
189			  struct xgbe_ring *ring, unsigned int rdesc_count)
190{
191	DBGPR("-->xgbe_init_ring\n");
192
193	if (!ring)
194		return 0;
195
196	/* Descriptors */
197	ring->rdesc_count = rdesc_count;
198	ring->rdesc = dma_alloc_coherent(pdata->dev,
199					 (sizeof(struct xgbe_ring_desc) *
200					  rdesc_count), &ring->rdesc_dma,
201					 GFP_KERNEL);
202	if (!ring->rdesc)
203		return -ENOMEM;
204
205	/* Descriptor information */
206	ring->rdata = kcalloc(rdesc_count, sizeof(struct xgbe_ring_data),
207			      GFP_KERNEL);
208	if (!ring->rdata)
209		return -ENOMEM;
210
211	netif_dbg(pdata, drv, pdata->netdev,
212		  "rdesc=%p, rdesc_dma=%pad, rdata=%p\n",
213		  ring->rdesc, &ring->rdesc_dma, ring->rdata);
214
215	DBGPR("<--xgbe_init_ring\n");
216
217	return 0;
218}
219
220static int xgbe_alloc_ring_resources(struct xgbe_prv_data *pdata)
221{
222	struct xgbe_channel *channel;
223	unsigned int i;
224	int ret;
225
226	DBGPR("-->xgbe_alloc_ring_resources\n");
227
228	channel = pdata->channel;
229	for (i = 0; i < pdata->channel_count; i++, channel++) {
230		netif_dbg(pdata, drv, pdata->netdev, "%s - Tx ring:\n",
231			  channel->name);
232
233		ret = xgbe_init_ring(pdata, channel->tx_ring,
234				     pdata->tx_desc_count);
235		if (ret) {
236			netdev_alert(pdata->netdev,
237				     "error initializing Tx ring\n");
238			goto err_ring;
239		}
240
241		netif_dbg(pdata, drv, pdata->netdev, "%s - Rx ring:\n",
242			  channel->name);
243
244		ret = xgbe_init_ring(pdata, channel->rx_ring,
245				     pdata->rx_desc_count);
246		if (ret) {
247			netdev_alert(pdata->netdev,
248				     "error initializing Rx ring\n");
249			goto err_ring;
250		}
251	}
252
253	DBGPR("<--xgbe_alloc_ring_resources\n");
254
255	return 0;
256
257err_ring:
258	xgbe_free_ring_resources(pdata);
259
260	return ret;
261}
262
263static int xgbe_alloc_pages(struct xgbe_prv_data *pdata,
264			    struct xgbe_page_alloc *pa, gfp_t gfp, int order)
265{
266	struct page *pages = NULL;
267	dma_addr_t pages_dma;
268	int ret;
269
270	/* Try to obtain pages, decreasing order if necessary */
271	gfp |= __GFP_COLD | __GFP_COMP | __GFP_NOWARN;
272	while (order >= 0) {
273		pages = alloc_pages(gfp, order);
274		if (pages)
275			break;
276
277		order--;
278	}
279	if (!pages)
280		return -ENOMEM;
281
282	/* Map the pages */
283	pages_dma = dma_map_page(pdata->dev, pages, 0,
284				 PAGE_SIZE << order, DMA_FROM_DEVICE);
285	ret = dma_mapping_error(pdata->dev, pages_dma);
286	if (ret) {
287		put_page(pages);
288		return ret;
289	}
290
291	pa->pages = pages;
292	pa->pages_len = PAGE_SIZE << order;
293	pa->pages_offset = 0;
294	pa->pages_dma = pages_dma;
295
296	return 0;
297}
298
299static void xgbe_set_buffer_data(struct xgbe_buffer_data *bd,
300				 struct xgbe_page_alloc *pa,
301				 unsigned int len)
302{
303	get_page(pa->pages);
304	bd->pa = *pa;
305
306	bd->dma_base = pa->pages_dma;
307	bd->dma_off = pa->pages_offset;
308	bd->dma_len = len;
309
310	pa->pages_offset += len;
311	if ((pa->pages_offset + len) > pa->pages_len) {
312		/* This data descriptor is responsible for unmapping page(s) */
313		bd->pa_unmap = *pa;
314
315		/* Get a new allocation next time */
316		pa->pages = NULL;
317		pa->pages_len = 0;
318		pa->pages_offset = 0;
319		pa->pages_dma = 0;
320	}
321}
322
323static int xgbe_map_rx_buffer(struct xgbe_prv_data *pdata,
324			      struct xgbe_ring *ring,
325			      struct xgbe_ring_data *rdata)
326{
327	int order, ret;
328
329	if (!ring->rx_hdr_pa.pages) {
330		ret = xgbe_alloc_pages(pdata, &ring->rx_hdr_pa, GFP_ATOMIC, 0);
331		if (ret)
332			return ret;
333	}
334
335	if (!ring->rx_buf_pa.pages) {
336		order = max_t(int, PAGE_ALLOC_COSTLY_ORDER - 1, 0);
337		ret = xgbe_alloc_pages(pdata, &ring->rx_buf_pa, GFP_ATOMIC,
338				       order);
339		if (ret)
340			return ret;
341	}
342
343	/* Set up the header page info */
344	xgbe_set_buffer_data(&rdata->rx.hdr, &ring->rx_hdr_pa,
345			     XGBE_SKB_ALLOC_SIZE);
346
347	/* Set up the buffer page info */
348	xgbe_set_buffer_data(&rdata->rx.buf, &ring->rx_buf_pa,
349			     pdata->rx_buf_size);
350
351	return 0;
352}
353
354static void xgbe_wrapper_tx_descriptor_init(struct xgbe_prv_data *pdata)
355{
356	struct xgbe_hw_if *hw_if = &pdata->hw_if;
357	struct xgbe_channel *channel;
358	struct xgbe_ring *ring;
359	struct xgbe_ring_data *rdata;
360	struct xgbe_ring_desc *rdesc;
361	dma_addr_t rdesc_dma;
362	unsigned int i, j;
363
364	DBGPR("-->xgbe_wrapper_tx_descriptor_init\n");
365
366	channel = pdata->channel;
367	for (i = 0; i < pdata->channel_count; i++, channel++) {
368		ring = channel->tx_ring;
369		if (!ring)
370			break;
371
372		rdesc = ring->rdesc;
373		rdesc_dma = ring->rdesc_dma;
374
375		for (j = 0; j < ring->rdesc_count; j++) {
376			rdata = XGBE_GET_DESC_DATA(ring, j);
377
378			rdata->rdesc = rdesc;
379			rdata->rdesc_dma = rdesc_dma;
380
381			rdesc++;
382			rdesc_dma += sizeof(struct xgbe_ring_desc);
383		}
384
385		ring->cur = 0;
386		ring->dirty = 0;
387		memset(&ring->tx, 0, sizeof(ring->tx));
388
389		hw_if->tx_desc_init(channel);
390	}
391
392	DBGPR("<--xgbe_wrapper_tx_descriptor_init\n");
393}
394
395static void xgbe_wrapper_rx_descriptor_init(struct xgbe_prv_data *pdata)
396{
397	struct xgbe_hw_if *hw_if = &pdata->hw_if;
398	struct xgbe_channel *channel;
399	struct xgbe_ring *ring;
400	struct xgbe_ring_desc *rdesc;
401	struct xgbe_ring_data *rdata;
402	dma_addr_t rdesc_dma;
403	unsigned int i, j;
404
405	DBGPR("-->xgbe_wrapper_rx_descriptor_init\n");
406
407	channel = pdata->channel;
408	for (i = 0; i < pdata->channel_count; i++, channel++) {
409		ring = channel->rx_ring;
410		if (!ring)
411			break;
412
413		rdesc = ring->rdesc;
414		rdesc_dma = ring->rdesc_dma;
415
416		for (j = 0; j < ring->rdesc_count; j++) {
417			rdata = XGBE_GET_DESC_DATA(ring, j);
418
419			rdata->rdesc = rdesc;
420			rdata->rdesc_dma = rdesc_dma;
421
422			if (xgbe_map_rx_buffer(pdata, ring, rdata))
423				break;
424
425			rdesc++;
426			rdesc_dma += sizeof(struct xgbe_ring_desc);
427		}
428
429		ring->cur = 0;
430		ring->dirty = 0;
431
432		hw_if->rx_desc_init(channel);
433	}
434
435	DBGPR("<--xgbe_wrapper_rx_descriptor_init\n");
436}
437
438static void xgbe_unmap_rdata(struct xgbe_prv_data *pdata,
439			     struct xgbe_ring_data *rdata)
440{
441	if (rdata->skb_dma) {
442		if (rdata->mapped_as_page) {
443			dma_unmap_page(pdata->dev, rdata->skb_dma,
444				       rdata->skb_dma_len, DMA_TO_DEVICE);
445		} else {
446			dma_unmap_single(pdata->dev, rdata->skb_dma,
447					 rdata->skb_dma_len, DMA_TO_DEVICE);
448		}
449		rdata->skb_dma = 0;
450		rdata->skb_dma_len = 0;
451	}
452
453	if (rdata->skb) {
454		dev_kfree_skb_any(rdata->skb);
455		rdata->skb = NULL;
456	}
457
458	if (rdata->rx.hdr.pa.pages)
459		put_page(rdata->rx.hdr.pa.pages);
460
461	if (rdata->rx.hdr.pa_unmap.pages) {
462		dma_unmap_page(pdata->dev, rdata->rx.hdr.pa_unmap.pages_dma,
463			       rdata->rx.hdr.pa_unmap.pages_len,
464			       DMA_FROM_DEVICE);
465		put_page(rdata->rx.hdr.pa_unmap.pages);
466	}
467
468	if (rdata->rx.buf.pa.pages)
469		put_page(rdata->rx.buf.pa.pages);
470
471	if (rdata->rx.buf.pa_unmap.pages) {
472		dma_unmap_page(pdata->dev, rdata->rx.buf.pa_unmap.pages_dma,
473			       rdata->rx.buf.pa_unmap.pages_len,
474			       DMA_FROM_DEVICE);
475		put_page(rdata->rx.buf.pa_unmap.pages);
476	}
477
478	memset(&rdata->tx, 0, sizeof(rdata->tx));
479	memset(&rdata->rx, 0, sizeof(rdata->rx));
480
481	rdata->mapped_as_page = 0;
482
483	if (rdata->state_saved) {
484		rdata->state_saved = 0;
485		rdata->state.skb = NULL;
486		rdata->state.len = 0;
487		rdata->state.error = 0;
488	}
489}
490
491static int xgbe_map_tx_skb(struct xgbe_channel *channel, struct sk_buff *skb)
492{
493	struct xgbe_prv_data *pdata = channel->pdata;
494	struct xgbe_ring *ring = channel->tx_ring;
495	struct xgbe_ring_data *rdata;
496	struct xgbe_packet_data *packet;
497	struct skb_frag_struct *frag;
498	dma_addr_t skb_dma;
499	unsigned int start_index, cur_index;
500	unsigned int offset, tso, vlan, datalen, len;
501	unsigned int i;
502
503	DBGPR("-->xgbe_map_tx_skb: cur = %d\n", ring->cur);
504
505	offset = 0;
506	start_index = ring->cur;
507	cur_index = ring->cur;
508
509	packet = &ring->packet_data;
510	packet->rdesc_count = 0;
511	packet->length = 0;
512
513	tso = XGMAC_GET_BITS(packet->attributes, TX_PACKET_ATTRIBUTES,
514			     TSO_ENABLE);
515	vlan = XGMAC_GET_BITS(packet->attributes, TX_PACKET_ATTRIBUTES,
516			      VLAN_CTAG);
517
518	/* Save space for a context descriptor if needed */
519	if ((tso && (packet->mss != ring->tx.cur_mss)) ||
520	    (vlan && (packet->vlan_ctag != ring->tx.cur_vlan_ctag)))
521		cur_index++;
522	rdata = XGBE_GET_DESC_DATA(ring, cur_index);
523
524	if (tso) {
525		/* Map the TSO header */
526		skb_dma = dma_map_single(pdata->dev, skb->data,
527					 packet->header_len, DMA_TO_DEVICE);
528		if (dma_mapping_error(pdata->dev, skb_dma)) {
529			netdev_alert(pdata->netdev, "dma_map_single failed\n");
530			goto err_out;
531		}
532		rdata->skb_dma = skb_dma;
533		rdata->skb_dma_len = packet->header_len;
534		netif_dbg(pdata, tx_queued, pdata->netdev,
535			  "skb header: index=%u, dma=%pad, len=%u\n",
536			  cur_index, &skb_dma, packet->header_len);
537
538		offset = packet->header_len;
539
540		packet->length += packet->header_len;
541
542		cur_index++;
543		rdata = XGBE_GET_DESC_DATA(ring, cur_index);
544	}
545
546	/* Map the (remainder of the) packet */
547	for (datalen = skb_headlen(skb) - offset; datalen; ) {
548		len = min_t(unsigned int, datalen, XGBE_TX_MAX_BUF_SIZE);
549
550		skb_dma = dma_map_single(pdata->dev, skb->data + offset, len,
551					 DMA_TO_DEVICE);
552		if (dma_mapping_error(pdata->dev, skb_dma)) {
553			netdev_alert(pdata->netdev, "dma_map_single failed\n");
554			goto err_out;
555		}
556		rdata->skb_dma = skb_dma;
557		rdata->skb_dma_len = len;
558		netif_dbg(pdata, tx_queued, pdata->netdev,
559			  "skb data: index=%u, dma=%pad, len=%u\n",
560			  cur_index, &skb_dma, len);
561
562		datalen -= len;
563		offset += len;
564
565		packet->length += len;
566
567		cur_index++;
568		rdata = XGBE_GET_DESC_DATA(ring, cur_index);
569	}
570
571	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
572		netif_dbg(pdata, tx_queued, pdata->netdev,
573			  "mapping frag %u\n", i);
574
575		frag = &skb_shinfo(skb)->frags[i];
576		offset = 0;
577
578		for (datalen = skb_frag_size(frag); datalen; ) {
579			len = min_t(unsigned int, datalen,
580				    XGBE_TX_MAX_BUF_SIZE);
581
582			skb_dma = skb_frag_dma_map(pdata->dev, frag, offset,
583						   len, DMA_TO_DEVICE);
584			if (dma_mapping_error(pdata->dev, skb_dma)) {
585				netdev_alert(pdata->netdev,
586					     "skb_frag_dma_map failed\n");
587				goto err_out;
588			}
589			rdata->skb_dma = skb_dma;
590			rdata->skb_dma_len = len;
591			rdata->mapped_as_page = 1;
592			netif_dbg(pdata, tx_queued, pdata->netdev,
593				  "skb frag: index=%u, dma=%pad, len=%u\n",
594				  cur_index, &skb_dma, len);
595
596			datalen -= len;
597			offset += len;
598
599			packet->length += len;
600
601			cur_index++;
602			rdata = XGBE_GET_DESC_DATA(ring, cur_index);
603		}
604	}
605
606	/* Save the skb address in the last entry. We always have some data
607	 * that has been mapped so rdata is always advanced past the last
608	 * piece of mapped data - use the entry pointed to by cur_index - 1.
609	 */
610	rdata = XGBE_GET_DESC_DATA(ring, cur_index - 1);
611	rdata->skb = skb;
612
613	/* Save the number of descriptor entries used */
614	packet->rdesc_count = cur_index - start_index;
615
616	DBGPR("<--xgbe_map_tx_skb: count=%u\n", packet->rdesc_count);
617
618	return packet->rdesc_count;
619
620err_out:
621	while (start_index < cur_index) {
622		rdata = XGBE_GET_DESC_DATA(ring, start_index++);
623		xgbe_unmap_rdata(pdata, rdata);
624	}
625
626	DBGPR("<--xgbe_map_tx_skb: count=0\n");
627
628	return 0;
629}
630
631void xgbe_init_function_ptrs_desc(struct xgbe_desc_if *desc_if)
632{
633	DBGPR("-->xgbe_init_function_ptrs_desc\n");
634
635	desc_if->alloc_ring_resources = xgbe_alloc_ring_resources;
636	desc_if->free_ring_resources = xgbe_free_ring_resources;
637	desc_if->map_tx_skb = xgbe_map_tx_skb;
638	desc_if->map_rx_buffer = xgbe_map_rx_buffer;
639	desc_if->unmap_rdata = xgbe_unmap_rdata;
640	desc_if->wrapper_tx_desc_init = xgbe_wrapper_tx_descriptor_init;
641	desc_if->wrapper_rx_desc_init = xgbe_wrapper_rx_descriptor_init;
642
643	DBGPR("<--xgbe_init_function_ptrs_desc\n");
644}
645