drivers/net/ethernet/amd/xgbe/xgbe-desc.c - kernel/msm-4.19 - Gitiles

 /*
  * AMD 10Gb Ethernet driver
  *
  * This file is available to you under your choice of the following two
  * licenses:
  *
  * License 1: GPLv2
  *
  * Copyright (c) 2014 Advanced Micro Devices, Inc.
  *
  * This file is free software; you may copy, redistribute and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 2 of the License, or (at
  * your option) any later version.
  *
  * This file 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.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  * This file incorporates work covered by the following copyright and
  * permission notice:
  *     The Synopsys DWC ETHER XGMAC Software Driver and documentation
  *     (hereinafter "Software") is an unsupported proprietary work of Synopsys,
  *     Inc. unless otherwise expressly agreed to in writing between Synopsys
  *     and you.
  *
  *     The Software IS NOT an item of Licensed Software or Licensed Product
  *     under any End User Software License Agreement or Agreement for Licensed
  *     Product with Synopsys or any supplement thereto.  Permission is hereby
  *     granted, free of charge, to any person obtaining a copy of this software
  *     annotated with this license and the Software, to deal in the Software
  *     without restriction, including without limitation the rights to use,
  *     copy, modify, merge, publish, distribute, sublicense, and/or sell copies
  *     of the Software, and to permit persons to whom the Software is furnished
  *     to do so, subject to the following conditions:
  *
  *     The above copyright notice and this permission notice shall be included
  *     in all copies or substantial portions of the Software.
  *
  *     THIS SOFTWARE IS BEING DISTRIBUTED BY SYNOPSYS SOLELY ON AN "AS IS"
  *     BASIS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  *     TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  *     PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. IN NO EVENT SHALL SYNOPSYS
  *     BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  *     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  *     SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  *     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  *     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  *     THE POSSIBILITY OF SUCH DAMAGE.
  *
  *
  * License 2: Modified BSD
  *
  * Copyright (c) 2014 Advanced Micro Devices, Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *     * Redistributions of source code must retain the above copyright
  *       notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above copyright
  *       notice, this list of conditions and the following disclaimer in the
  *       documentation and/or other materials provided with the distribution.
  *     * Neither the name of Advanced Micro Devices, Inc. nor the
  *       names of its contributors may be used to endorse or promote products
  *       derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * This file incorporates work covered by the following copyright and
  * permission notice:
  *     The Synopsys DWC ETHER XGMAC Software Driver and documentation
  *     (hereinafter "Software") is an unsupported proprietary work of Synopsys,
  *     Inc. unless otherwise expressly agreed to in writing between Synopsys
  *     and you.
  *
  *     The Software IS NOT an item of Licensed Software or Licensed Product
  *     under any End User Software License Agreement or Agreement for Licensed
  *     Product with Synopsys or any supplement thereto.  Permission is hereby
  *     granted, free of charge, to any person obtaining a copy of this software
  *     annotated with this license and the Software, to deal in the Software
  *     without restriction, including without limitation the rights to use,
  *     copy, modify, merge, publish, distribute, sublicense, and/or sell copies
  *     of the Software, and to permit persons to whom the Software is furnished
  *     to do so, subject to the following conditions:
  *
  *     The above copyright notice and this permission notice shall be included
  *     in all copies or substantial portions of the Software.
  *
  *     THIS SOFTWARE IS BEING DISTRIBUTED BY SYNOPSYS SOLELY ON AN "AS IS"
  *     BASIS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  *     TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  *     PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. IN NO EVENT SHALL SYNOPSYS
  *     BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  *     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  *     SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  *     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  *     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  *     THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "xgbe.h"
 #include "xgbe-common.h"

 static void xgbe_unmap_rdata(struct xgbe_prv_data *, struct xgbe_ring_data *);

 static void xgbe_free_ring(struct xgbe_prv_data *pdata,
 			   struct xgbe_ring *ring)
 {
 	struct xgbe_ring_data *rdata;
 	unsigned int i;

 	if (!ring)
 		return;

 	if (ring->rdata) {
 		for (i = 0; i < ring->rdesc_count; i++) {
 			rdata = XGBE_GET_DESC_DATA(ring, i);
 			xgbe_unmap_rdata(pdata, rdata);
 		}

 		kfree(ring->rdata);
 		ring->rdata = NULL;
 	}

 	if (ring->rx_hdr_pa.pages) {
 		dma_unmap_page(pdata->dev, ring->rx_hdr_pa.pages_dma,
 			       ring->rx_hdr_pa.pages_len, DMA_FROM_DEVICE);
 		put_page(ring->rx_hdr_pa.pages);

 		ring->rx_hdr_pa.pages = NULL;
 		ring->rx_hdr_pa.pages_len = 0;
 		ring->rx_hdr_pa.pages_offset = 0;
 		ring->rx_hdr_pa.pages_dma = 0;
 	}

 	if (ring->rx_buf_pa.pages) {
 		dma_unmap_page(pdata->dev, ring->rx_buf_pa.pages_dma,
 			       ring->rx_buf_pa.pages_len, DMA_FROM_DEVICE);
 		put_page(ring->rx_buf_pa.pages);

 		ring->rx_buf_pa.pages = NULL;
 		ring->rx_buf_pa.pages_len = 0;
 		ring->rx_buf_pa.pages_offset = 0;
 		ring->rx_buf_pa.pages_dma = 0;
 	}

 	if (ring->rdesc) {
 		dma_free_coherent(pdata->dev,
 				  (sizeof(struct xgbe_ring_desc) *
 				   ring->rdesc_count),
 				  ring->rdesc, ring->rdesc_dma);
 		ring->rdesc = NULL;
 	}
 }

 static void xgbe_free_ring_resources(struct xgbe_prv_data *pdata)
 {
 	struct xgbe_channel *channel;
 	unsigned int i;

 	DBGPR("-->xgbe_free_ring_resources\n");

 	channel = pdata->channel;
 	for (i = 0; i < pdata->channel_count; i++, channel++) {
 		xgbe_free_ring(pdata, channel->tx_ring);
 		xgbe_free_ring(pdata, channel->rx_ring);
 	}

 	DBGPR("<--xgbe_free_ring_resources\n");
 }

 static int xgbe_init_ring(struct xgbe_prv_data *pdata,
 			  struct xgbe_ring *ring, unsigned int rdesc_count)
 {
 	DBGPR("-->xgbe_init_ring\n");

 	if (!ring)
 		return 0;

 	/* Descriptors */
 	ring->rdesc_count = rdesc_count;
 	ring->rdesc = dma_alloc_coherent(pdata->dev,
 					 (sizeof(struct xgbe_ring_desc) *
 					  rdesc_count), &ring->rdesc_dma,
 					 GFP_KERNEL);
 	if (!ring->rdesc)
 		return -ENOMEM;

 	/* Descriptor information */
 	ring->rdata = kcalloc(rdesc_count, sizeof(struct xgbe_ring_data),
 			      GFP_KERNEL);
 	if (!ring->rdata)
 		return -ENOMEM;

 	netif_dbg(pdata, drv, pdata->netdev,
 		  "rdesc=%p, rdesc_dma=%pad, rdata=%p\n",
 		  ring->rdesc, &ring->rdesc_dma, ring->rdata);

 	DBGPR("<--xgbe_init_ring\n");

 	return 0;
 }

 static int xgbe_alloc_ring_resources(struct xgbe_prv_data *pdata)
 {
 	struct xgbe_channel *channel;
 	unsigned int i;
 	int ret;

 	DBGPR("-->xgbe_alloc_ring_resources\n");

 	channel = pdata->channel;
 	for (i = 0; i < pdata->channel_count; i++, channel++) {
 		netif_dbg(pdata, drv, pdata->netdev, "%s - Tx ring:\n",
 			  channel->name);

 		ret = xgbe_init_ring(pdata, channel->tx_ring,
 				     pdata->tx_desc_count);
 		if (ret) {
 			netdev_alert(pdata->netdev,
 				     "error initializing Tx ring\n");
 			goto err_ring;
 		}

 		netif_dbg(pdata, drv, pdata->netdev, "%s - Rx ring:\n",
 			  channel->name);

 		ret = xgbe_init_ring(pdata, channel->rx_ring,
 				     pdata->rx_desc_count);
 		if (ret) {
 			netdev_alert(pdata->netdev,
 				     "error initializing Rx ring\n");
 			goto err_ring;
 		}
 	}

 	DBGPR("<--xgbe_alloc_ring_resources\n");

 	return 0;

 err_ring:
 	xgbe_free_ring_resources(pdata);

 	return ret;
 }

 static int xgbe_alloc_pages(struct xgbe_prv_data *pdata,
 			    struct xgbe_page_alloc *pa, gfp_t gfp, int order)
 {
 	struct page *pages = NULL;
 	dma_addr_t pages_dma;
 	int ret;

 	/* Try to obtain pages, decreasing order if necessary */
 	gfp |= __GFP_COLD | __GFP_COMP | __GFP_NOWARN;
 	while (order >= 0) {
 		pages = alloc_pages(gfp, order);
 		if (pages)
 			break;

 		order--;
 	}
 	if (!pages)
 		return -ENOMEM;

 	/* Map the pages */
 	pages_dma = dma_map_page(pdata->dev, pages, 0,
 				 PAGE_SIZE << order, DMA_FROM_DEVICE);
 	ret = dma_mapping_error(pdata->dev, pages_dma);
 	if (ret) {
 		put_page(pages);
 		return ret;
 	}

 	pa->pages = pages;
 	pa->pages_len = PAGE_SIZE << order;
 	pa->pages_offset = 0;
 	pa->pages_dma = pages_dma;

 	return 0;
 }

 static void xgbe_set_buffer_data(struct xgbe_buffer_data *bd,
 				 struct xgbe_page_alloc *pa,
 				 unsigned int len)
 {
 	get_page(pa->pages);
 	bd->pa = *pa;

 	bd->dma_base = pa->pages_dma;
 	bd->dma_off = pa->pages_offset;
 	bd->dma_len = len;

 	pa->pages_offset += len;
 	if ((pa->pages_offset + len) > pa->pages_len) {
 		/* This data descriptor is responsible for unmapping page(s) */
 		bd->pa_unmap = *pa;

 		/* Get a new allocation next time */
 		pa->pages = NULL;
 		pa->pages_len = 0;
 		pa->pages_offset = 0;
 		pa->pages_dma = 0;
 	}
 }

 static int xgbe_map_rx_buffer(struct xgbe_prv_data *pdata,
 			      struct xgbe_ring *ring,
 			      struct xgbe_ring_data *rdata)
 {
 	int ret;

 	if (!ring->rx_hdr_pa.pages) {
 		ret = xgbe_alloc_pages(pdata, &ring->rx_hdr_pa, GFP_ATOMIC, 0);
 		if (ret)
 			return ret;
 	}

 	if (!ring->rx_buf_pa.pages) {
 		ret = xgbe_alloc_pages(pdata, &ring->rx_buf_pa, GFP_ATOMIC,
 				       PAGE_ALLOC_COSTLY_ORDER);
 		if (ret)
 			return ret;
 	}

 	/* Set up the header page info */
 	xgbe_set_buffer_data(&rdata->rx.hdr, &ring->rx_hdr_pa,
 			     XGBE_SKB_ALLOC_SIZE);

 	/* Set up the buffer page info */
 	xgbe_set_buffer_data(&rdata->rx.buf, &ring->rx_buf_pa,
 			     pdata->rx_buf_size);

 	return 0;
 }

 static void xgbe_wrapper_tx_descriptor_init(struct xgbe_prv_data *pdata)
 {
 	struct xgbe_hw_if *hw_if = &pdata->hw_if;
 	struct xgbe_channel *channel;
 	struct xgbe_ring *ring;
 	struct xgbe_ring_data *rdata;
 	struct xgbe_ring_desc *rdesc;
 	dma_addr_t rdesc_dma;
 	unsigned int i, j;

 	DBGPR("-->xgbe_wrapper_tx_descriptor_init\n");

 	channel = pdata->channel;
 	for (i = 0; i < pdata->channel_count; i++, channel++) {
 		ring = channel->tx_ring;
 		if (!ring)
 			break;

 		rdesc = ring->rdesc;
 		rdesc_dma = ring->rdesc_dma;

 		for (j = 0; j < ring->rdesc_count; j++) {
 			rdata = XGBE_GET_DESC_DATA(ring, j);

 			rdata->rdesc = rdesc;
 			rdata->rdesc_dma = rdesc_dma;

 			rdesc++;
 			rdesc_dma += sizeof(struct xgbe_ring_desc);
 		}

 		ring->cur = 0;
 		ring->dirty = 0;
 		memset(&ring->tx, 0, sizeof(ring->tx));

 		hw_if->tx_desc_init(channel);
 	}

 	DBGPR("<--xgbe_wrapper_tx_descriptor_init\n");
 }

 static void xgbe_wrapper_rx_descriptor_init(struct xgbe_prv_data *pdata)
 {
 	struct xgbe_hw_if *hw_if = &pdata->hw_if;
 	struct xgbe_channel *channel;
 	struct xgbe_ring *ring;
 	struct xgbe_ring_desc *rdesc;
 	struct xgbe_ring_data *rdata;
 	dma_addr_t rdesc_dma;
 	unsigned int i, j;

 	DBGPR("-->xgbe_wrapper_rx_descriptor_init\n");

 	channel = pdata->channel;
 	for (i = 0; i < pdata->channel_count; i++, channel++) {
 		ring = channel->rx_ring;
 		if (!ring)
 			break;

 		rdesc = ring->rdesc;
 		rdesc_dma = ring->rdesc_dma;

 		for (j = 0; j < ring->rdesc_count; j++) {
 			rdata = XGBE_GET_DESC_DATA(ring, j);

 			rdata->rdesc = rdesc;
 			rdata->rdesc_dma = rdesc_dma;

 			if (xgbe_map_rx_buffer(pdata, ring, rdata))
 				break;

 			rdesc++;
 			rdesc_dma += sizeof(struct xgbe_ring_desc);
 		}

 		ring->cur = 0;
 		ring->dirty = 0;

 		hw_if->rx_desc_init(channel);
 	}

 	DBGPR("<--xgbe_wrapper_rx_descriptor_init\n");
 }

 static void xgbe_unmap_rdata(struct xgbe_prv_data *pdata,
 			     struct xgbe_ring_data *rdata)
 {
 	if (rdata->skb_dma) {
 		if (rdata->mapped_as_page) {
 			dma_unmap_page(pdata->dev, rdata->skb_dma,
 				       rdata->skb_dma_len, DMA_TO_DEVICE);
 		} else {
 			dma_unmap_single(pdata->dev, rdata->skb_dma,
 					 rdata->skb_dma_len, DMA_TO_DEVICE);
 		}
 		rdata->skb_dma = 0;
 		rdata->skb_dma_len = 0;
 	}

 	if (rdata->skb) {
 		dev_kfree_skb_any(rdata->skb);
 		rdata->skb = NULL;
 	}

 	if (rdata->rx.hdr.pa.pages)
 		put_page(rdata->rx.hdr.pa.pages);

 	if (rdata->rx.hdr.pa_unmap.pages) {
 		dma_unmap_page(pdata->dev, rdata->rx.hdr.pa_unmap.pages_dma,
 			       rdata->rx.hdr.pa_unmap.pages_len,
 			       DMA_FROM_DEVICE);
 		put_page(rdata->rx.hdr.pa_unmap.pages);
 	}

 	if (rdata->rx.buf.pa.pages)
 		put_page(rdata->rx.buf.pa.pages);

 	if (rdata->rx.buf.pa_unmap.pages) {
 		dma_unmap_page(pdata->dev, rdata->rx.buf.pa_unmap.pages_dma,
 			       rdata->rx.buf.pa_unmap.pages_len,
 			       DMA_FROM_DEVICE);
 		put_page(rdata->rx.buf.pa_unmap.pages);
 	}

 	memset(&rdata->tx, 0, sizeof(rdata->tx));
 	memset(&rdata->rx, 0, sizeof(rdata->rx));

 	rdata->mapped_as_page = 0;

 	if (rdata->state_saved) {
 		rdata->state_saved = 0;
 		rdata->state.skb = NULL;
 		rdata->state.len = 0;
 		rdata->state.error = 0;
 	}
 }

 static int xgbe_map_tx_skb(struct xgbe_channel *channel, struct sk_buff *skb)
 {
 	struct xgbe_prv_data *pdata = channel->pdata;
 	struct xgbe_ring *ring = channel->tx_ring;
 	struct xgbe_ring_data *rdata;
 	struct xgbe_packet_data *packet;
 	struct skb_frag_struct *frag;
 	dma_addr_t skb_dma;
 	unsigned int start_index, cur_index;
 	unsigned int offset, tso, vlan, datalen, len;
 	unsigned int i;

 	DBGPR("-->xgbe_map_tx_skb: cur = %d\n", ring->cur);

 	offset = 0;
 	start_index = ring->cur;
 	cur_index = ring->cur;

 	packet = &ring->packet_data;
 	packet->rdesc_count = 0;
 	packet->length = 0;

 	tso = XGMAC_GET_BITS(packet->attributes, TX_PACKET_ATTRIBUTES,
 			     TSO_ENABLE);
 	vlan = XGMAC_GET_BITS(packet->attributes, TX_PACKET_ATTRIBUTES,
 			      VLAN_CTAG);

 	/* Save space for a context descriptor if needed */
 	if ((tso && (packet->mss != ring->tx.cur_mss)) ||
 	    (vlan && (packet->vlan_ctag != ring->tx.cur_vlan_ctag)))
 		cur_index++;
 	rdata = XGBE_GET_DESC_DATA(ring, cur_index);

 	if (tso) {
 		/* Map the TSO header */
 		skb_dma = dma_map_single(pdata->dev, skb->data,
 					 packet->header_len, DMA_TO_DEVICE);
 		if (dma_mapping_error(pdata->dev, skb_dma)) {
 			netdev_alert(pdata->netdev, "dma_map_single failed\n");
 			goto err_out;
 		}
 		rdata->skb_dma = skb_dma;
 		rdata->skb_dma_len = packet->header_len;
 		netif_dbg(pdata, tx_queued, pdata->netdev,
 			  "skb header: index=%u, dma=%pad, len=%u\n",
 			  cur_index, &skb_dma, packet->header_len);

 		offset = packet->header_len;

 		packet->length += packet->header_len;

 		cur_index++;
 		rdata = XGBE_GET_DESC_DATA(ring, cur_index);
 	}

 	/* Map the (remainder of the) packet */
 	for (datalen = skb_headlen(skb) - offset; datalen; ) {
 		len = min_t(unsigned int, datalen, XGBE_TX_MAX_BUF_SIZE);

 		skb_dma = dma_map_single(pdata->dev, skb->data + offset, len,
 					 DMA_TO_DEVICE);
 		if (dma_mapping_error(pdata->dev, skb_dma)) {
 			netdev_alert(pdata->netdev, "dma_map_single failed\n");
 			goto err_out;
 		}
 		rdata->skb_dma = skb_dma;
 		rdata->skb_dma_len = len;
 		netif_dbg(pdata, tx_queued, pdata->netdev,
 			  "skb data: index=%u, dma=%pad, len=%u\n",
 			  cur_index, &skb_dma, len);

 		datalen -= len;
 		offset += len;

 		packet->length += len;

 		cur_index++;
 		rdata = XGBE_GET_DESC_DATA(ring, cur_index);
 	}

 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 		netif_dbg(pdata, tx_queued, pdata->netdev,
 			  "mapping frag %u\n", i);

 		frag = &skb_shinfo(skb)->frags[i];
 		offset = 0;

 		for (datalen = skb_frag_size(frag); datalen; ) {
 			len = min_t(unsigned int, datalen,
 				    XGBE_TX_MAX_BUF_SIZE);

 			skb_dma = skb_frag_dma_map(pdata->dev, frag, offset,
 						   len, DMA_TO_DEVICE);
 			if (dma_mapping_error(pdata->dev, skb_dma)) {
 				netdev_alert(pdata->netdev,
 					     "skb_frag_dma_map failed\n");
 				goto err_out;
 			}
 			rdata->skb_dma = skb_dma;
 			rdata->skb_dma_len = len;
 			rdata->mapped_as_page = 1;
 			netif_dbg(pdata, tx_queued, pdata->netdev,
 				  "skb frag: index=%u, dma=%pad, len=%u\n",
 				  cur_index, &skb_dma, len);

 			datalen -= len;
 			offset += len;

 			packet->length += len;

 			cur_index++;
 			rdata = XGBE_GET_DESC_DATA(ring, cur_index);
 		}
 	}

 	/* Save the skb address in the last entry. We always have some data
 	 * that has been mapped so rdata is always advanced past the last
 	 * piece of mapped data - use the entry pointed to by cur_index - 1.
 	 */
 	rdata = XGBE_GET_DESC_DATA(ring, cur_index - 1);
 	rdata->skb = skb;

 	/* Save the number of descriptor entries used */
 	packet->rdesc_count = cur_index - start_index;

 	DBGPR("<--xgbe_map_tx_skb: count=%u\n", packet->rdesc_count);

 	return packet->rdesc_count;

 err_out:
 	while (start_index < cur_index) {
 		rdata = XGBE_GET_DESC_DATA(ring, start_index++);
 		xgbe_unmap_rdata(pdata, rdata);
 	}

 	DBGPR("<--xgbe_map_tx_skb: count=0\n");

 	return 0;
 }

 void xgbe_init_function_ptrs_desc(struct xgbe_desc_if *desc_if)
 {
 	DBGPR("-->xgbe_init_function_ptrs_desc\n");

 	desc_if->alloc_ring_resources = xgbe_alloc_ring_resources;
 	desc_if->free_ring_resources = xgbe_free_ring_resources;
 	desc_if->map_tx_skb = xgbe_map_tx_skb;
 	desc_if->map_rx_buffer = xgbe_map_rx_buffer;
 	desc_if->unmap_rdata = xgbe_unmap_rdata;
 	desc_if->wrapper_tx_desc_init = xgbe_wrapper_tx_descriptor_init;
 	desc_if->wrapper_rx_desc_init = xgbe_wrapper_rx_descriptor_init;

 	DBGPR("<--xgbe_init_function_ptrs_desc\n");
 }
	/*
	* AMD 10Gb Ethernet driver
	*
	* This file is available to you under your choice of the following two
	* licenses:
	*
	* License 1: GPLv2
	*
	* Copyright (c) 2014 Advanced Micro Devices, Inc.
	*
	* This file is free software; you may copy, redistribute and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation, either version 2 of the License, or (at
	* your option) any later version.
	*
	* This file 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.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	*
	* This file incorporates work covered by the following copyright and
	* permission notice:
	* The Synopsys DWC ETHER XGMAC Software Driver and documentation
	* (hereinafter "Software") is an unsupported proprietary work of Synopsys,
	* Inc. unless otherwise expressly agreed to in writing between Synopsys
	* and you.
	*
	* The Software IS NOT an item of Licensed Software or Licensed Product
	* under any End User Software License Agreement or Agreement for Licensed
	* Product with Synopsys or any supplement thereto. Permission is hereby
	* granted, free of charge, to any person obtaining a copy of this software
	* annotated with this license and the Software, to deal in the Software
	* without restriction, including without limitation the rights to use,
	* copy, modify, merge, publish, distribute, sublicense, and/or sell copies
	* of the Software, and to permit persons to whom the Software is furnished
	* to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included
	* in all copies or substantial portions of the Software.
	*
	* THIS SOFTWARE IS BEING DISTRIBUTED BY SYNOPSYS SOLELY ON AN "AS IS"
	* BASIS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
	* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	* PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. IN NO EVENT SHALL SYNOPSYS
	* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
	* THE POSSIBILITY OF SUCH DAMAGE.
	*
	*
	* License 2: Modified BSD
	*
	* Copyright (c) 2014 Advanced Micro Devices, Inc.
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* * Neither the name of Advanced Micro Devices, Inc. nor the
	* names of its contributors may be used to endorse or promote products
	* derived from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
	* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
	* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	* This file incorporates work covered by the following copyright and
	* permission notice:
	* The Synopsys DWC ETHER XGMAC Software Driver and documentation
	* (hereinafter "Software") is an unsupported proprietary work of Synopsys,
	* Inc. unless otherwise expressly agreed to in writing between Synopsys
	* and you.
	*
	* The Software IS NOT an item of Licensed Software or Licensed Product
	* under any End User Software License Agreement or Agreement for Licensed
	* Product with Synopsys or any supplement thereto. Permission is hereby
	* granted, free of charge, to any person obtaining a copy of this software
	* annotated with this license and the Software, to deal in the Software
	* without restriction, including without limitation the rights to use,
	* copy, modify, merge, publish, distribute, sublicense, and/or sell copies
	* of the Software, and to permit persons to whom the Software is furnished
	* to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included
	* in all copies or substantial portions of the Software.
	*
	* THIS SOFTWARE IS BEING DISTRIBUTED BY SYNOPSYS SOLELY ON AN "AS IS"
	* BASIS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
	* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	* PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. IN NO EVENT SHALL SYNOPSYS
	* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
	* THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "xgbe.h"
	#include "xgbe-common.h"

	static void xgbe_unmap_rdata(struct xgbe_prv_data , struct xgbe_ring_data );

	static void xgbe_free_ring(struct xgbe_prv_data *pdata,
	struct xgbe_ring *ring)
	{
	struct xgbe_ring_data *rdata;
	unsigned int i;

	if (!ring)
	return;

	if (ring->rdata) {
	for (i = 0; i < ring->rdesc_count; i++) {
	rdata = XGBE_GET_DESC_DATA(ring, i);
	xgbe_unmap_rdata(pdata, rdata);
	}

	kfree(ring->rdata);
	ring->rdata = NULL;
	}

	if (ring->rx_hdr_pa.pages) {
	dma_unmap_page(pdata->dev, ring->rx_hdr_pa.pages_dma,
	ring->rx_hdr_pa.pages_len, DMA_FROM_DEVICE);
	put_page(ring->rx_hdr_pa.pages);

	ring->rx_hdr_pa.pages = NULL;
	ring->rx_hdr_pa.pages_len = 0;
	ring->rx_hdr_pa.pages_offset = 0;
	ring->rx_hdr_pa.pages_dma = 0;
	}

	if (ring->rx_buf_pa.pages) {
	dma_unmap_page(pdata->dev, ring->rx_buf_pa.pages_dma,
	ring->rx_buf_pa.pages_len, DMA_FROM_DEVICE);
	put_page(ring->rx_buf_pa.pages);

	ring->rx_buf_pa.pages = NULL;
	ring->rx_buf_pa.pages_len = 0;
	ring->rx_buf_pa.pages_offset = 0;
	ring->rx_buf_pa.pages_dma = 0;
	}

	if (ring->rdesc) {
	dma_free_coherent(pdata->dev,
	(sizeof(struct xgbe_ring_desc) *
	ring->rdesc_count),
	ring->rdesc, ring->rdesc_dma);
	ring->rdesc = NULL;
	}
	}

	static void xgbe_free_ring_resources(struct xgbe_prv_data *pdata)
	{
	struct xgbe_channel *channel;
	unsigned int i;

	DBGPR("-->xgbe_free_ring_resources\n");

	channel = pdata->channel;
	for (i = 0; i < pdata->channel_count; i++, channel++) {
	xgbe_free_ring(pdata, channel->tx_ring);
	xgbe_free_ring(pdata, channel->rx_ring);
	}

	DBGPR("<--xgbe_free_ring_resources\n");
	}

	static int xgbe_init_ring(struct xgbe_prv_data *pdata,
	struct xgbe_ring *ring, unsigned int rdesc_count)
	{
	DBGPR("-->xgbe_init_ring\n");

	if (!ring)
	return 0;

	/* Descriptors */
	ring->rdesc_count = rdesc_count;
	ring->rdesc = dma_alloc_coherent(pdata->dev,
	(sizeof(struct xgbe_ring_desc) *
	rdesc_count), &ring->rdesc_dma,
	GFP_KERNEL);
	if (!ring->rdesc)
	return -ENOMEM;

	/* Descriptor information */
	ring->rdata = kcalloc(rdesc_count, sizeof(struct xgbe_ring_data),
	GFP_KERNEL);
	if (!ring->rdata)
	return -ENOMEM;

	netif_dbg(pdata, drv, pdata->netdev,
	"rdesc=%p, rdesc_dma=%pad, rdata=%p\n",
	ring->rdesc, &ring->rdesc_dma, ring->rdata);

	DBGPR("<--xgbe_init_ring\n");

	return 0;
	}

	static int xgbe_alloc_ring_resources(struct xgbe_prv_data *pdata)
	{
	struct xgbe_channel *channel;
	unsigned int i;
	int ret;

	DBGPR("-->xgbe_alloc_ring_resources\n");

	channel = pdata->channel;
	for (i = 0; i < pdata->channel_count; i++, channel++) {
	netif_dbg(pdata, drv, pdata->netdev, "%s - Tx ring:\n",
	channel->name);

	ret = xgbe_init_ring(pdata, channel->tx_ring,
	pdata->tx_desc_count);
	if (ret) {
	netdev_alert(pdata->netdev,
	"error initializing Tx ring\n");
	goto err_ring;
	}

	netif_dbg(pdata, drv, pdata->netdev, "%s - Rx ring:\n",
	channel->name);

	ret = xgbe_init_ring(pdata, channel->rx_ring,
	pdata->rx_desc_count);
	if (ret) {
	netdev_alert(pdata->netdev,
	"error initializing Rx ring\n");
	goto err_ring;
	}
	}

	DBGPR("<--xgbe_alloc_ring_resources\n");

	return 0;

	err_ring:
	xgbe_free_ring_resources(pdata);

	return ret;
	}

	static int xgbe_alloc_pages(struct xgbe_prv_data *pdata,
	struct xgbe_page_alloc *pa, gfp_t gfp, int order)
	{
	struct page *pages = NULL;
	dma_addr_t pages_dma;
	int ret;

	/* Try to obtain pages, decreasing order if necessary */
	gfp \|= __GFP_COLD \| __GFP_COMP \| __GFP_NOWARN;
	while (order >= 0) {
	pages = alloc_pages(gfp, order);
	if (pages)
	break;

	order--;
	}
	if (!pages)
	return -ENOMEM;

	/* Map the pages */
	pages_dma = dma_map_page(pdata->dev, pages, 0,
	PAGE_SIZE << order, DMA_FROM_DEVICE);
	ret = dma_mapping_error(pdata->dev, pages_dma);
	if (ret) {
	put_page(pages);
	return ret;
	}

	pa->pages = pages;
	pa->pages_len = PAGE_SIZE << order;
	pa->pages_offset = 0;
	pa->pages_dma = pages_dma;

	return 0;
	}

	static void xgbe_set_buffer_data(struct xgbe_buffer_data *bd,
	struct xgbe_page_alloc *pa,
	unsigned int len)
	{
	get_page(pa->pages);
	bd->pa = *pa;

	bd->dma_base = pa->pages_dma;
	bd->dma_off = pa->pages_offset;
	bd->dma_len = len;

	pa->pages_offset += len;
	if ((pa->pages_offset + len) > pa->pages_len) {
	/* This data descriptor is responsible for unmapping page(s) */
	bd->pa_unmap = *pa;

	/* Get a new allocation next time */
	pa->pages = NULL;
	pa->pages_len = 0;
	pa->pages_offset = 0;
	pa->pages_dma = 0;
	}
	}

	static int xgbe_map_rx_buffer(struct xgbe_prv_data *pdata,
	struct xgbe_ring *ring,
	struct xgbe_ring_data *rdata)
	{
	int ret;

	if (!ring->rx_hdr_pa.pages) {
	ret = xgbe_alloc_pages(pdata, &ring->rx_hdr_pa, GFP_ATOMIC, 0);
	if (ret)
	return ret;
	}

	if (!ring->rx_buf_pa.pages) {
	ret = xgbe_alloc_pages(pdata, &ring->rx_buf_pa, GFP_ATOMIC,
	PAGE_ALLOC_COSTLY_ORDER);
	if (ret)
	return ret;
	}

	/* Set up the header page info */
	xgbe_set_buffer_data(&rdata->rx.hdr, &ring->rx_hdr_pa,
	XGBE_SKB_ALLOC_SIZE);

	/* Set up the buffer page info */
	xgbe_set_buffer_data(&rdata->rx.buf, &ring->rx_buf_pa,
	pdata->rx_buf_size);

	return 0;
	}

	static void xgbe_wrapper_tx_descriptor_init(struct xgbe_prv_data *pdata)
	{
	struct xgbe_hw_if *hw_if = &pdata->hw_if;
	struct xgbe_channel *channel;
	struct xgbe_ring *ring;
	struct xgbe_ring_data *rdata;
	struct xgbe_ring_desc *rdesc;
	dma_addr_t rdesc_dma;
	unsigned int i, j;

	DBGPR("-->xgbe_wrapper_tx_descriptor_init\n");

	channel = pdata->channel;
	for (i = 0; i < pdata->channel_count; i++, channel++) {
	ring = channel->tx_ring;
	if (!ring)
	break;

	rdesc = ring->rdesc;
	rdesc_dma = ring->rdesc_dma;

	for (j = 0; j < ring->rdesc_count; j++) {
	rdata = XGBE_GET_DESC_DATA(ring, j);

	rdata->rdesc = rdesc;
	rdata->rdesc_dma = rdesc_dma;

	rdesc++;
	rdesc_dma += sizeof(struct xgbe_ring_desc);
	}

	ring->cur = 0;
	ring->dirty = 0;
	memset(&ring->tx, 0, sizeof(ring->tx));

	hw_if->tx_desc_init(channel);
	}

	DBGPR("<--xgbe_wrapper_tx_descriptor_init\n");
	}

	static void xgbe_wrapper_rx_descriptor_init(struct xgbe_prv_data *pdata)
	{
	struct xgbe_hw_if *hw_if = &pdata->hw_if;
	struct xgbe_channel *channel;
	struct xgbe_ring *ring;
	struct xgbe_ring_desc *rdesc;
	struct xgbe_ring_data *rdata;
	dma_addr_t rdesc_dma;
	unsigned int i, j;

	DBGPR("-->xgbe_wrapper_rx_descriptor_init\n");

	channel = pdata->channel;
	for (i = 0; i < pdata->channel_count; i++, channel++) {
	ring = channel->rx_ring;
	if (!ring)
	break;

	rdesc = ring->rdesc;
	rdesc_dma = ring->rdesc_dma;

	for (j = 0; j < ring->rdesc_count; j++) {
	rdata = XGBE_GET_DESC_DATA(ring, j);

	rdata->rdesc = rdesc;
	rdata->rdesc_dma = rdesc_dma;

	if (xgbe_map_rx_buffer(pdata, ring, rdata))
	break;

	rdesc++;
	rdesc_dma += sizeof(struct xgbe_ring_desc);
	}

	ring->cur = 0;
	ring->dirty = 0;

	hw_if->rx_desc_init(channel);
	}

	DBGPR("<--xgbe_wrapper_rx_descriptor_init\n");
	}

	static void xgbe_unmap_rdata(struct xgbe_prv_data *pdata,
	struct xgbe_ring_data *rdata)
	{
	if (rdata->skb_dma) {
	if (rdata->mapped_as_page) {
	dma_unmap_page(pdata->dev, rdata->skb_dma,
	rdata->skb_dma_len, DMA_TO_DEVICE);
	} else {
	dma_unmap_single(pdata->dev, rdata->skb_dma,
	rdata->skb_dma_len, DMA_TO_DEVICE);
	}
	rdata->skb_dma = 0;
	rdata->skb_dma_len = 0;
	}

	if (rdata->skb) {
	dev_kfree_skb_any(rdata->skb);
	rdata->skb = NULL;
	}

	if (rdata->rx.hdr.pa.pages)
	put_page(rdata->rx.hdr.pa.pages);

	if (rdata->rx.hdr.pa_unmap.pages) {
	dma_unmap_page(pdata->dev, rdata->rx.hdr.pa_unmap.pages_dma,
	rdata->rx.hdr.pa_unmap.pages_len,
	DMA_FROM_DEVICE);
	put_page(rdata->rx.hdr.pa_unmap.pages);
	}

	if (rdata->rx.buf.pa.pages)
	put_page(rdata->rx.buf.pa.pages);

	if (rdata->rx.buf.pa_unmap.pages) {
	dma_unmap_page(pdata->dev, rdata->rx.buf.pa_unmap.pages_dma,
	rdata->rx.buf.pa_unmap.pages_len,
	DMA_FROM_DEVICE);
	put_page(rdata->rx.buf.pa_unmap.pages);
	}

	memset(&rdata->tx, 0, sizeof(rdata->tx));
	memset(&rdata->rx, 0, sizeof(rdata->rx));

	rdata->mapped_as_page = 0;

	if (rdata->state_saved) {
	rdata->state_saved = 0;
	rdata->state.skb = NULL;
	rdata->state.len = 0;
	rdata->state.error = 0;
	}
	}

	static int xgbe_map_tx_skb(struct xgbe_channel channel, struct sk_buff skb)
	{
	struct xgbe_prv_data *pdata = channel->pdata;
	struct xgbe_ring *ring = channel->tx_ring;
	struct xgbe_ring_data *rdata;
	struct xgbe_packet_data *packet;
	struct skb_frag_struct *frag;
	dma_addr_t skb_dma;
	unsigned int start_index, cur_index;
	unsigned int offset, tso, vlan, datalen, len;
	unsigned int i;

	DBGPR("-->xgbe_map_tx_skb: cur = %d\n", ring->cur);

	offset = 0;
	start_index = ring->cur;
	cur_index = ring->cur;

	packet = &ring->packet_data;
	packet->rdesc_count = 0;
	packet->length = 0;

	tso = XGMAC_GET_BITS(packet->attributes, TX_PACKET_ATTRIBUTES,
	TSO_ENABLE);
	vlan = XGMAC_GET_BITS(packet->attributes, TX_PACKET_ATTRIBUTES,
	VLAN_CTAG);

	/* Save space for a context descriptor if needed */
	if ((tso && (packet->mss != ring->tx.cur_mss)) \|\|
	(vlan && (packet->vlan_ctag != ring->tx.cur_vlan_ctag)))
	cur_index++;
	rdata = XGBE_GET_DESC_DATA(ring, cur_index);

	if (tso) {
	/* Map the TSO header */
	skb_dma = dma_map_single(pdata->dev, skb->data,
	packet->header_len, DMA_TO_DEVICE);
	if (dma_mapping_error(pdata->dev, skb_dma)) {
	netdev_alert(pdata->netdev, "dma_map_single failed\n");
	goto err_out;
	}
	rdata->skb_dma = skb_dma;
	rdata->skb_dma_len = packet->header_len;
	netif_dbg(pdata, tx_queued, pdata->netdev,
	"skb header: index=%u, dma=%pad, len=%u\n",
	cur_index, &skb_dma, packet->header_len);

	offset = packet->header_len;

	packet->length += packet->header_len;

	cur_index++;
	rdata = XGBE_GET_DESC_DATA(ring, cur_index);
	}

	/* Map the (remainder of the) packet */
	for (datalen = skb_headlen(skb) - offset; datalen; ) {
	len = min_t(unsigned int, datalen, XGBE_TX_MAX_BUF_SIZE);

	skb_dma = dma_map_single(pdata->dev, skb->data + offset, len,
	DMA_TO_DEVICE);
	if (dma_mapping_error(pdata->dev, skb_dma)) {
	netdev_alert(pdata->netdev, "dma_map_single failed\n");
	goto err_out;
	}
	rdata->skb_dma = skb_dma;
	rdata->skb_dma_len = len;
	netif_dbg(pdata, tx_queued, pdata->netdev,
	"skb data: index=%u, dma=%pad, len=%u\n",
	cur_index, &skb_dma, len);

	datalen -= len;
	offset += len;

	packet->length += len;

	cur_index++;
	rdata = XGBE_GET_DESC_DATA(ring, cur_index);
	}

	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
	netif_dbg(pdata, tx_queued, pdata->netdev,
	"mapping frag %u\n", i);

	frag = &skb_shinfo(skb)->frags[i];
	offset = 0;

	for (datalen = skb_frag_size(frag); datalen; ) {
	len = min_t(unsigned int, datalen,
	XGBE_TX_MAX_BUF_SIZE);

	skb_dma = skb_frag_dma_map(pdata->dev, frag, offset,
	len, DMA_TO_DEVICE);
	if (dma_mapping_error(pdata->dev, skb_dma)) {
	netdev_alert(pdata->netdev,
	"skb_frag_dma_map failed\n");
	goto err_out;
	}
	rdata->skb_dma = skb_dma;
	rdata->skb_dma_len = len;
	rdata->mapped_as_page = 1;
	netif_dbg(pdata, tx_queued, pdata->netdev,
	"skb frag: index=%u, dma=%pad, len=%u\n",
	cur_index, &skb_dma, len);

	datalen -= len;
	offset += len;

	packet->length += len;

	cur_index++;
	rdata = XGBE_GET_DESC_DATA(ring, cur_index);
	}
	}

	/* Save the skb address in the last entry. We always have some data
	* that has been mapped so rdata is always advanced past the last
	* piece of mapped data - use the entry pointed to by cur_index - 1.
	*/
	rdata = XGBE_GET_DESC_DATA(ring, cur_index - 1);
	rdata->skb = skb;

	/* Save the number of descriptor entries used */
	packet->rdesc_count = cur_index - start_index;

	DBGPR("<--xgbe_map_tx_skb: count=%u\n", packet->rdesc_count);

	return packet->rdesc_count;

	err_out:
	while (start_index < cur_index) {
	rdata = XGBE_GET_DESC_DATA(ring, start_index++);
	xgbe_unmap_rdata(pdata, rdata);
	}

	DBGPR("<--xgbe_map_tx_skb: count=0\n");

	return 0;
	}

	void xgbe_init_function_ptrs_desc(struct xgbe_desc_if *desc_if)
	{
	DBGPR("-->xgbe_init_function_ptrs_desc\n");

	desc_if->alloc_ring_resources = xgbe_alloc_ring_resources;
	desc_if->free_ring_resources = xgbe_free_ring_resources;
	desc_if->map_tx_skb = xgbe_map_tx_skb;
	desc_if->map_rx_buffer = xgbe_map_rx_buffer;
	desc_if->unmap_rdata = xgbe_unmap_rdata;
	desc_if->wrapper_tx_desc_init = xgbe_wrapper_tx_descriptor_init;
	desc_if->wrapper_rx_desc_init = xgbe_wrapper_rx_descriptor_init;

	DBGPR("<--xgbe_init_function_ptrs_desc\n");
	}