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 	for (i = 0; i < pdata->channel_count; i++) {
180 		channel = pdata->channel[i];
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 void *xgbe_alloc_node(size_t size, int node)
189 {
190 	void *mem;
191 
192 	mem = kzalloc_node(size, GFP_KERNEL, node);
193 	if (!mem)
194 		mem = kzalloc(size, GFP_KERNEL);
195 
196 	return mem;
197 }
198 
199 static void *xgbe_dma_alloc_node(struct device *dev, size_t size,
200 				 dma_addr_t *dma, int node)
201 {
202 	void *mem;
203 	int cur_node = dev_to_node(dev);
204 
205 	set_dev_node(dev, node);
206 	mem = dma_alloc_coherent(dev, size, dma, GFP_KERNEL);
207 	set_dev_node(dev, cur_node);
208 
209 	if (!mem)
210 		mem = dma_alloc_coherent(dev, size, dma, GFP_KERNEL);
211 
212 	return mem;
213 }
214 
215 static int xgbe_init_ring(struct xgbe_prv_data *pdata,
216 			  struct xgbe_ring *ring, unsigned int rdesc_count)
217 {
218 	size_t size;
219 
220 	if (!ring)
221 		return 0;
222 
223 	/* Descriptors */
224 	size = rdesc_count * sizeof(struct xgbe_ring_desc);
225 
226 	ring->rdesc_count = rdesc_count;
227 	ring->rdesc = xgbe_dma_alloc_node(pdata->dev, size, &ring->rdesc_dma,
228 					  ring->node);
229 	if (!ring->rdesc)
230 		return -ENOMEM;
231 
232 	/* Descriptor information */
233 	size = rdesc_count * sizeof(struct xgbe_ring_data);
234 
235 	ring->rdata = xgbe_alloc_node(size, ring->node);
236 	if (!ring->rdata)
237 		return -ENOMEM;
238 
239 	netif_dbg(pdata, drv, pdata->netdev,
240 		  "rdesc=%p, rdesc_dma=%pad, rdata=%p, node=%d\n",
241 		  ring->rdesc, &ring->rdesc_dma, ring->rdata, ring->node);
242 
243 	return 0;
244 }
245 
246 static int xgbe_alloc_ring_resources(struct xgbe_prv_data *pdata)
247 {
248 	struct xgbe_channel *channel;
249 	unsigned int i;
250 	int ret;
251 
252 	for (i = 0; i < pdata->channel_count; i++) {
253 		channel = pdata->channel[i];
254 		netif_dbg(pdata, drv, pdata->netdev, "%s - Tx ring:\n",
255 			  channel->name);
256 
257 		ret = xgbe_init_ring(pdata, channel->tx_ring,
258 				     pdata->tx_desc_count);
259 		if (ret) {
260 			netdev_alert(pdata->netdev,
261 				     "error initializing Tx ring\n");
262 			goto err_ring;
263 		}
264 
265 		netif_dbg(pdata, drv, pdata->netdev, "%s - Rx ring:\n",
266 			  channel->name);
267 
268 		ret = xgbe_init_ring(pdata, channel->rx_ring,
269 				     pdata->rx_desc_count);
270 		if (ret) {
271 			netdev_alert(pdata->netdev,
272 				     "error initializing Rx ring\n");
273 			goto err_ring;
274 		}
275 	}
276 
277 	return 0;
278 
279 err_ring:
280 	xgbe_free_ring_resources(pdata);
281 
282 	return ret;
283 }
284 
285 static int xgbe_alloc_pages(struct xgbe_prv_data *pdata,
286 			    struct xgbe_page_alloc *pa, int alloc_order,
287 			    int node)
288 {
289 	struct page *pages = NULL;
290 	dma_addr_t pages_dma;
291 	gfp_t gfp;
292 	int order;
293 
294 again:
295 	order = alloc_order;
296 
297 	/* Try to obtain pages, decreasing order if necessary */
298 	gfp = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
299 	while (order >= 0) {
300 		pages = alloc_pages_node(node, gfp, order);
301 		if (pages)
302 			break;
303 
304 		order--;
305 	}
306 
307 	/* If we couldn't get local pages, try getting from anywhere */
308 	if (!pages && (node != NUMA_NO_NODE)) {
309 		node = NUMA_NO_NODE;
310 		goto again;
311 	}
312 
313 	if (!pages)
314 		return -ENOMEM;
315 
316 	/* Map the pages */
317 	pages_dma = dma_map_page(pdata->dev, pages, 0,
318 				 PAGE_SIZE << order, DMA_FROM_DEVICE);
319 	if (dma_mapping_error(pdata->dev, pages_dma)) {
320 		put_page(pages);
321 		return -ENOMEM;
322 	}
323 
324 	pa->pages = pages;
325 	pa->pages_len = PAGE_SIZE << order;
326 	pa->pages_offset = 0;
327 	pa->pages_dma = pages_dma;
328 
329 	return 0;
330 }
331 
332 static void xgbe_set_buffer_data(struct xgbe_buffer_data *bd,
333 				 struct xgbe_page_alloc *pa,
334 				 unsigned int len)
335 {
336 	get_page(pa->pages);
337 	bd->pa = *pa;
338 
339 	bd->dma_base = pa->pages_dma;
340 	bd->dma_off = pa->pages_offset;
341 	bd->dma_len = len;
342 
343 	pa->pages_offset += len;
344 	if ((pa->pages_offset + len) > pa->pages_len) {
345 		/* This data descriptor is responsible for unmapping page(s) */
346 		bd->pa_unmap = *pa;
347 
348 		/* Get a new allocation next time */
349 		pa->pages = NULL;
350 		pa->pages_len = 0;
351 		pa->pages_offset = 0;
352 		pa->pages_dma = 0;
353 	}
354 }
355 
356 static int xgbe_map_rx_buffer(struct xgbe_prv_data *pdata,
357 			      struct xgbe_ring *ring,
358 			      struct xgbe_ring_data *rdata)
359 {
360 	int ret;
361 
362 	if (!ring->rx_hdr_pa.pages) {
363 		ret = xgbe_alloc_pages(pdata, &ring->rx_hdr_pa, 0, ring->node);
364 		if (ret)
365 			return ret;
366 	}
367 
368 	if (!ring->rx_buf_pa.pages) {
369 		ret = xgbe_alloc_pages(pdata, &ring->rx_buf_pa,
370 				       PAGE_ALLOC_COSTLY_ORDER, ring->node);
371 		if (ret)
372 			return ret;
373 	}
374 
375 	/* Set up the header page info */
376 	xgbe_set_buffer_data(&rdata->rx.hdr, &ring->rx_hdr_pa,
377 			     XGBE_SKB_ALLOC_SIZE);
378 
379 	/* Set up the buffer page info */
380 	xgbe_set_buffer_data(&rdata->rx.buf, &ring->rx_buf_pa,
381 			     pdata->rx_buf_size);
382 
383 	return 0;
384 }
385 
386 static void xgbe_wrapper_tx_descriptor_init(struct xgbe_prv_data *pdata)
387 {
388 	struct xgbe_hw_if *hw_if = &pdata->hw_if;
389 	struct xgbe_channel *channel;
390 	struct xgbe_ring *ring;
391 	struct xgbe_ring_data *rdata;
392 	struct xgbe_ring_desc *rdesc;
393 	dma_addr_t rdesc_dma;
394 	unsigned int i, j;
395 
396 	DBGPR("-->xgbe_wrapper_tx_descriptor_init\n");
397 
398 	for (i = 0; i < pdata->channel_count; i++) {
399 		channel = pdata->channel[i];
400 		ring = channel->tx_ring;
401 		if (!ring)
402 			break;
403 
404 		rdesc = ring->rdesc;
405 		rdesc_dma = ring->rdesc_dma;
406 
407 		for (j = 0; j < ring->rdesc_count; j++) {
408 			rdata = XGBE_GET_DESC_DATA(ring, j);
409 
410 			rdata->rdesc = rdesc;
411 			rdata->rdesc_dma = rdesc_dma;
412 
413 			rdesc++;
414 			rdesc_dma += sizeof(struct xgbe_ring_desc);
415 		}
416 
417 		ring->cur = 0;
418 		ring->dirty = 0;
419 		memset(&ring->tx, 0, sizeof(ring->tx));
420 
421 		hw_if->tx_desc_init(channel);
422 	}
423 
424 	DBGPR("<--xgbe_wrapper_tx_descriptor_init\n");
425 }
426 
427 static void xgbe_wrapper_rx_descriptor_init(struct xgbe_prv_data *pdata)
428 {
429 	struct xgbe_hw_if *hw_if = &pdata->hw_if;
430 	struct xgbe_channel *channel;
431 	struct xgbe_ring *ring;
432 	struct xgbe_ring_desc *rdesc;
433 	struct xgbe_ring_data *rdata;
434 	dma_addr_t rdesc_dma;
435 	unsigned int i, j;
436 
437 	DBGPR("-->xgbe_wrapper_rx_descriptor_init\n");
438 
439 	for (i = 0; i < pdata->channel_count; i++) {
440 		channel = pdata->channel[i];
441 		ring = channel->rx_ring;
442 		if (!ring)
443 			break;
444 
445 		rdesc = ring->rdesc;
446 		rdesc_dma = ring->rdesc_dma;
447 
448 		for (j = 0; j < ring->rdesc_count; j++) {
449 			rdata = XGBE_GET_DESC_DATA(ring, j);
450 
451 			rdata->rdesc = rdesc;
452 			rdata->rdesc_dma = rdesc_dma;
453 
454 			if (xgbe_map_rx_buffer(pdata, ring, rdata))
455 				break;
456 
457 			rdesc++;
458 			rdesc_dma += sizeof(struct xgbe_ring_desc);
459 		}
460 
461 		ring->cur = 0;
462 		ring->dirty = 0;
463 
464 		hw_if->rx_desc_init(channel);
465 	}
466 
467 	DBGPR("<--xgbe_wrapper_rx_descriptor_init\n");
468 }
469 
470 static void xgbe_unmap_rdata(struct xgbe_prv_data *pdata,
471 			     struct xgbe_ring_data *rdata)
472 {
473 	if (rdata->skb_dma) {
474 		if (rdata->mapped_as_page) {
475 			dma_unmap_page(pdata->dev, rdata->skb_dma,
476 				       rdata->skb_dma_len, DMA_TO_DEVICE);
477 		} else {
478 			dma_unmap_single(pdata->dev, rdata->skb_dma,
479 					 rdata->skb_dma_len, DMA_TO_DEVICE);
480 		}
481 		rdata->skb_dma = 0;
482 		rdata->skb_dma_len = 0;
483 	}
484 
485 	if (rdata->skb) {
486 		dev_kfree_skb_any(rdata->skb);
487 		rdata->skb = NULL;
488 	}
489 
490 	if (rdata->rx.hdr.pa.pages)
491 		put_page(rdata->rx.hdr.pa.pages);
492 
493 	if (rdata->rx.hdr.pa_unmap.pages) {
494 		dma_unmap_page(pdata->dev, rdata->rx.hdr.pa_unmap.pages_dma,
495 			       rdata->rx.hdr.pa_unmap.pages_len,
496 			       DMA_FROM_DEVICE);
497 		put_page(rdata->rx.hdr.pa_unmap.pages);
498 	}
499 
500 	if (rdata->rx.buf.pa.pages)
501 		put_page(rdata->rx.buf.pa.pages);
502 
503 	if (rdata->rx.buf.pa_unmap.pages) {
504 		dma_unmap_page(pdata->dev, rdata->rx.buf.pa_unmap.pages_dma,
505 			       rdata->rx.buf.pa_unmap.pages_len,
506 			       DMA_FROM_DEVICE);
507 		put_page(rdata->rx.buf.pa_unmap.pages);
508 	}
509 
510 	memset(&rdata->tx, 0, sizeof(rdata->tx));
511 	memset(&rdata->rx, 0, sizeof(rdata->rx));
512 
513 	rdata->mapped_as_page = 0;
514 
515 	if (rdata->state_saved) {
516 		rdata->state_saved = 0;
517 		rdata->state.skb = NULL;
518 		rdata->state.len = 0;
519 		rdata->state.error = 0;
520 	}
521 }
522 
523 static int xgbe_map_tx_skb(struct xgbe_channel *channel, struct sk_buff *skb)
524 {
525 	struct xgbe_prv_data *pdata = channel->pdata;
526 	struct xgbe_ring *ring = channel->tx_ring;
527 	struct xgbe_ring_data *rdata;
528 	struct xgbe_packet_data *packet;
529 	skb_frag_t *frag;
530 	dma_addr_t skb_dma;
531 	unsigned int start_index, cur_index;
532 	unsigned int offset, tso, vlan, datalen, len;
533 	unsigned int i;
534 
535 	DBGPR("-->xgbe_map_tx_skb: cur = %d\n", ring->cur);
536 
537 	offset = 0;
538 	start_index = ring->cur;
539 	cur_index = ring->cur;
540 
541 	packet = &ring->packet_data;
542 	packet->rdesc_count = 0;
543 	packet->length = 0;
544 
545 	tso = XGMAC_GET_BITS(packet->attributes, TX_PACKET_ATTRIBUTES,
546 			     TSO_ENABLE);
547 	vlan = XGMAC_GET_BITS(packet->attributes, TX_PACKET_ATTRIBUTES,
548 			      VLAN_CTAG);
549 
550 	/* Save space for a context descriptor if needed */
551 	if ((tso && (packet->mss != ring->tx.cur_mss)) ||
552 	    (vlan && (packet->vlan_ctag != ring->tx.cur_vlan_ctag)))
553 		cur_index++;
554 	rdata = XGBE_GET_DESC_DATA(ring, cur_index);
555 
556 	if (tso) {
557 		/* Map the TSO header */
558 		skb_dma = dma_map_single(pdata->dev, skb->data,
559 					 packet->header_len, DMA_TO_DEVICE);
560 		if (dma_mapping_error(pdata->dev, skb_dma)) {
561 			netdev_alert(pdata->netdev, "dma_map_single failed\n");
562 			goto err_out;
563 		}
564 		rdata->skb_dma = skb_dma;
565 		rdata->skb_dma_len = packet->header_len;
566 		netif_dbg(pdata, tx_queued, pdata->netdev,
567 			  "skb header: index=%u, dma=%pad, len=%u\n",
568 			  cur_index, &skb_dma, packet->header_len);
569 
570 		offset = packet->header_len;
571 
572 		packet->length += packet->header_len;
573 
574 		cur_index++;
575 		rdata = XGBE_GET_DESC_DATA(ring, cur_index);
576 	}
577 
578 	/* Map the (remainder of the) packet */
579 	for (datalen = skb_headlen(skb) - offset; datalen; ) {
580 		len = min_t(unsigned int, datalen, XGBE_TX_MAX_BUF_SIZE);
581 
582 		skb_dma = dma_map_single(pdata->dev, skb->data + offset, len,
583 					 DMA_TO_DEVICE);
584 		if (dma_mapping_error(pdata->dev, skb_dma)) {
585 			netdev_alert(pdata->netdev, "dma_map_single failed\n");
586 			goto err_out;
587 		}
588 		rdata->skb_dma = skb_dma;
589 		rdata->skb_dma_len = len;
590 		netif_dbg(pdata, tx_queued, pdata->netdev,
591 			  "skb data: index=%u, dma=%pad, len=%u\n",
592 			  cur_index, &skb_dma, len);
593 
594 		datalen -= len;
595 		offset += len;
596 
597 		packet->length += len;
598 
599 		cur_index++;
600 		rdata = XGBE_GET_DESC_DATA(ring, cur_index);
601 	}
602 
603 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
604 		netif_dbg(pdata, tx_queued, pdata->netdev,
605 			  "mapping frag %u\n", i);
606 
607 		frag = &skb_shinfo(skb)->frags[i];
608 		offset = 0;
609 
610 		for (datalen = skb_frag_size(frag); datalen; ) {
611 			len = min_t(unsigned int, datalen,
612 				    XGBE_TX_MAX_BUF_SIZE);
613 
614 			skb_dma = skb_frag_dma_map(pdata->dev, frag, offset,
615 						   len, DMA_TO_DEVICE);
616 			if (dma_mapping_error(pdata->dev, skb_dma)) {
617 				netdev_alert(pdata->netdev,
618 					     "skb_frag_dma_map failed\n");
619 				goto err_out;
620 			}
621 			rdata->skb_dma = skb_dma;
622 			rdata->skb_dma_len = len;
623 			rdata->mapped_as_page = 1;
624 			netif_dbg(pdata, tx_queued, pdata->netdev,
625 				  "skb frag: index=%u, dma=%pad, len=%u\n",
626 				  cur_index, &skb_dma, len);
627 
628 			datalen -= len;
629 			offset += len;
630 
631 			packet->length += len;
632 
633 			cur_index++;
634 			rdata = XGBE_GET_DESC_DATA(ring, cur_index);
635 		}
636 	}
637 
638 	/* Save the skb address in the last entry. We always have some data
639 	 * that has been mapped so rdata is always advanced past the last
640 	 * piece of mapped data - use the entry pointed to by cur_index - 1.
641 	 */
642 	rdata = XGBE_GET_DESC_DATA(ring, cur_index - 1);
643 	rdata->skb = skb;
644 
645 	/* Save the number of descriptor entries used */
646 	packet->rdesc_count = cur_index - start_index;
647 
648 	DBGPR("<--xgbe_map_tx_skb: count=%u\n", packet->rdesc_count);
649 
650 	return packet->rdesc_count;
651 
652 err_out:
653 	while (start_index < cur_index) {
654 		rdata = XGBE_GET_DESC_DATA(ring, start_index++);
655 		xgbe_unmap_rdata(pdata, rdata);
656 	}
657 
658 	DBGPR("<--xgbe_map_tx_skb: count=0\n");
659 
660 	return 0;
661 }
662 
663 void xgbe_init_function_ptrs_desc(struct xgbe_desc_if *desc_if)
664 {
665 	DBGPR("-->xgbe_init_function_ptrs_desc\n");
666 
667 	desc_if->alloc_ring_resources = xgbe_alloc_ring_resources;
668 	desc_if->free_ring_resources = xgbe_free_ring_resources;
669 	desc_if->map_tx_skb = xgbe_map_tx_skb;
670 	desc_if->map_rx_buffer = xgbe_map_rx_buffer;
671 	desc_if->unmap_rdata = xgbe_unmap_rdata;
672 	desc_if->wrapper_tx_desc_init = xgbe_wrapper_tx_descriptor_init;
673 	desc_if->wrapper_rx_desc_init = xgbe_wrapper_rx_descriptor_init;
674 
675 	DBGPR("<--xgbe_init_function_ptrs_desc\n");
676 }
677