linux/net/mac802154/tx.c
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   1/*
   2 * Copyright 2007-2012 Siemens AG
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2
   6 * as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 * GNU General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public License along
  14 * with this program; if not, write to the Free Software Foundation, Inc.,
  15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16 *
  17 * Written by:
  18 * Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
  19 * Sergey Lapin <slapin@ossfans.org>
  20 * Maxim Gorbachyov <maxim.gorbachev@siemens.com>
  21 * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
  22 */
  23
  24#include <linux/netdevice.h>
  25#include <linux/if_arp.h>
  26#include <linux/crc-ccitt.h>
  27
  28#include <net/mac802154.h>
  29#include <net/wpan-phy.h>
  30
  31#include "mac802154.h"
  32
  33/* IEEE 802.15.4 transceivers can sleep during the xmit session, so process
  34 * packets through the workqueue.
  35 */
  36struct xmit_work {
  37        struct sk_buff *skb;
  38        struct work_struct work;
  39        struct mac802154_priv *priv;
  40        u8 chan;
  41        u8 page;
  42        u8 xmit_attempts;
  43};
  44
  45static void mac802154_xmit_worker(struct work_struct *work)
  46{
  47        struct xmit_work *xw = container_of(work, struct xmit_work, work);
  48        int res;
  49
  50        mutex_lock(&xw->priv->phy->pib_lock);
  51        if (xw->priv->phy->current_channel != xw->chan ||
  52            xw->priv->phy->current_page != xw->page) {
  53                res = xw->priv->ops->set_channel(&xw->priv->hw,
  54                                                  xw->page,
  55                                                  xw->chan);
  56                if (res) {
  57                        pr_debug("set_channel failed\n");
  58                        goto out;
  59                }
  60        }
  61
  62        res = xw->priv->ops->xmit(&xw->priv->hw, xw->skb);
  63
  64out:
  65        mutex_unlock(&xw->priv->phy->pib_lock);
  66
  67        if (res) {
  68                if (xw->xmit_attempts++ < MAC802154_MAX_XMIT_ATTEMPTS) {
  69                        queue_work(xw->priv->dev_workqueue, &xw->work);
  70                        return;
  71                } else
  72                        pr_debug("transmission failed for %d times",
  73                                 MAC802154_MAX_XMIT_ATTEMPTS);
  74        }
  75
  76        dev_kfree_skb(xw->skb);
  77
  78        kfree(xw);
  79}
  80
  81netdev_tx_t mac802154_tx(struct mac802154_priv *priv, struct sk_buff *skb,
  82                         u8 page, u8 chan)
  83{
  84        struct xmit_work *work;
  85
  86        if (!(priv->phy->channels_supported[page] & (1 << chan))) {
  87                WARN_ON(1);
  88                kfree_skb(skb);
  89                return NETDEV_TX_OK;
  90        }
  91
  92        mac802154_monitors_rx(mac802154_to_priv(&priv->hw), skb);
  93
  94        if (!(priv->hw.flags & IEEE802154_HW_OMIT_CKSUM)) {
  95                u16 crc = crc_ccitt(0, skb->data, skb->len);
  96                u8 *data = skb_put(skb, 2);
  97                data[0] = crc & 0xff;
  98                data[1] = crc >> 8;
  99        }
 100
 101        if (skb_cow_head(skb, priv->hw.extra_tx_headroom)) {
 102                kfree_skb(skb);
 103                return NETDEV_TX_OK;
 104        }
 105
 106        work = kzalloc(sizeof(struct xmit_work), GFP_ATOMIC);
 107        if (!work) {
 108                kfree_skb(skb);
 109                return NETDEV_TX_BUSY;
 110        }
 111
 112        INIT_WORK(&work->work, mac802154_xmit_worker);
 113        work->skb = skb;
 114        work->priv = priv;
 115        work->page = page;
 116        work->chan = chan;
 117        work->xmit_attempts = 0;
 118
 119        queue_work(priv->dev_workqueue, &work->work);
 120
 121        return NETDEV_TX_OK;
 122}
 123
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