/*
 * 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");

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

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

static void *xgbe_alloc_node(size_t size, int node)
{
        void *mem;

        mem = kzalloc_node(size, GFP_KERNEL, node);
        if (!mem)
                mem = kzalloc(size, GFP_KERNEL);

        return mem;
}

static void *xgbe_dma_alloc_node(struct device *dev, size_t size,
                                 dma_addr_t *dma, int node)
{
        void *mem;
        int cur_node = dev_to_node(dev);

        set_dev_node(dev, node);
        mem = dma_alloc_coherent(dev, size, dma, GFP_KERNEL);
        set_dev_node(dev, cur_node);

        if (!mem)
                mem = dma_alloc_coherent(dev, size, dma, GFP_KERNEL);

        return mem;
}

static int xgbe_init_ring(struct xgbe_prv_data *pdata,
                          struct xgbe_ring *ring, unsigned int rdesc_count)
{
        size_t size;

        if (!ring)
                return 0;

        /* Descriptors */
        size = rdesc_count * sizeof(struct xgbe_ring_desc);

        ring->rdesc_count = rdesc_count;
        ring->rdesc = xgbe_dma_alloc_node(pdata->dev, size, &ring->rdesc_dma,
                                          ring->node);
        if (!ring->rdesc)
                return -ENOMEM;

        /* Descriptor information */
        size = rdesc_count * sizeof(struct xgbe_ring_data);

        ring->rdata = xgbe_alloc_node(size, ring->node);
        if (!ring->rdata)
                return -ENOMEM;

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

        return 0;
}

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

        for (i = 0; i < pdata->channel_count; i++) {
                channel = pdata->channel[i];
                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;
                }
        }

        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, int alloc_order,
                            int node)
{
        struct page *pages = NULL;
        dma_addr_t pages_dma;
        gfp_t gfp;
        int order, ret;

again:
        order = alloc_order;

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

                order--;
        }

        /* If we couldn't get local pages, try getting from anywhere */
        if (!pages && (node != NUMA_NO_NODE)) {
                node = NUMA_NO_NODE;
                goto again;
        }

        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, 0, ring->node);
                if (ret)
                        return ret;
        }

        if (!ring->rx_buf_pa.pages) {
                ret = xgbe_alloc_pages(pdata, &ring->rx_buf_pa,
                                       PAGE_ALLOC_COSTLY_ORDER, ring->node);
                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");

        for (i = 0; i < pdata->channel_count; i++) {
                channel = pdata->channel[i];
                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");

        for (i = 0; i < pdata->channel_count; i++) {
                channel = pdata->channel[i];
                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");
}