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 
120 static void xgbe_unmap_rdata(struct xgbe_prv_data *, struct xgbe_ring_data *);
121 
122 static 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 
172 static 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 
188 static 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 
220 static 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 
257 err_ring:
258 	xgbe_free_ring_resources(pdata);
259 
260 	return ret;
261 }
262 
263 static 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 
299 static 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 
323 static 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 
354 static 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 
395 static 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 
438 static 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 
491 static 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 
620 err_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 
631 void 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