LXR linux/net/mac802154/tx.c

   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/ieee802154_netdev.h>
  29#include <net/mac802154.h>
  30#include <net/wpan-phy.h>
  31
  32#include "mac802154.h"
  33
  34/* IEEE 802.15.4 transceivers can sleep during the xmit session, so process
  35 * packets through the workqueue.
  36 */
  37struct xmit_work {
  38        struct sk_buff *skb;
  39        struct work_struct work;
  40        struct mac802154_priv *priv;
  41        u8 chan;
  42        u8 page;
  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        struct mac802154_sub_if_data *sdata;
  49        int res;
  50
  51        mutex_lock(&xw->priv->phy->pib_lock);
  52        if (xw->priv->phy->current_channel != xw->chan ||
  53            xw->priv->phy->current_page != xw->page) {
  54                res = xw->priv->ops->set_channel(&xw->priv->hw,
  55                                                  xw->page,
  56                                                  xw->chan);
  57                if (res) {
  58                        pr_debug("set_channel failed\n");
  59                        goto out;
  60                }
  61
  62                xw->priv->phy->current_channel = xw->chan;
  63                xw->priv->phy->current_page = xw->page;
  64        }
  65
  66        res = xw->priv->ops->xmit(&xw->priv->hw, xw->skb);
  67        if (res)
  68                pr_debug("transmission failed\n");
  69
  70out:
  71        mutex_unlock(&xw->priv->phy->pib_lock);
  72
  73        /* Restart the netif queue on each sub_if_data object. */
  74        rcu_read_lock();
  75        list_for_each_entry_rcu(sdata, &xw->priv->slaves, list)
  76                netif_wake_queue(sdata->dev);
  77        rcu_read_unlock();
  78
  79        dev_kfree_skb(xw->skb);
  80
  81        kfree(xw);
  82}
  83
  84netdev_tx_t mac802154_tx(struct mac802154_priv *priv, struct sk_buff *skb,
  85                         u8 page, u8 chan)
  86{
  87        struct xmit_work *work;
  88        struct mac802154_sub_if_data *sdata;
  89
  90        if (!(priv->phy->channels_supported[page] & (1 << chan))) {
  91                WARN_ON(1);
  92                kfree_skb(skb);
  93                return NETDEV_TX_OK;
  94        }
  95
  96        mac802154_monitors_rx(mac802154_to_priv(&priv->hw), skb);
  97
  98        if (!(priv->hw.flags & IEEE802154_HW_OMIT_CKSUM)) {
  99                u16 crc = crc_ccitt(0, skb->data, skb->len);
 100                u8 *data = skb_put(skb, 2);
 101                data[0] = crc & 0xff;
 102                data[1] = crc >> 8;
 103        }
 104
 105        if (skb_cow_head(skb, priv->hw.extra_tx_headroom)) {
 106                kfree_skb(skb);
 107                return NETDEV_TX_OK;
 108        }
 109
 110        work = kzalloc(sizeof(struct xmit_work), GFP_ATOMIC);
 111        if (!work) {
 112                kfree_skb(skb);
 113                return NETDEV_TX_BUSY;
 114        }
 115
 116        /* Stop the netif queue on each sub_if_data object. */
 117        rcu_read_lock();
 118        list_for_each_entry_rcu(sdata, &priv->slaves, list)
 119                netif_stop_queue(sdata->dev);
 120        rcu_read_unlock();
 121
 122        INIT_WORK(&work->work, mac802154_xmit_worker);
 123        work->skb = skb;
 124        work->priv = priv;
 125        work->page = page;
 126        work->chan = chan;
 127
 128        queue_work(priv->dev_workqueue, &work->work);
 129
 130        return NETDEV_TX_OK;
 131}
 132