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  * Written by:
  14  * Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
  15  * Sergey Lapin <slapin@ossfans.org>
  16  * Maxim Gorbachyov <maxim.gorbachev@siemens.com>
  17  * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
  18  */
  19
  20 #include <linux/netdevice.h>
  21 #include <linux/if_arp.h>
  22 #include <linux/crc-ccitt.h>
  23
  24 #include <net/ieee802154_netdev.h>
  25 #include <net/mac802154.h>
  26 #include <net/wpan-phy.h>
  27
  28 #include "ieee802154_i.h"
  29
  30 /* IEEE 802.15.4 transceivers can sleep during the xmit session, so process
  31  * packets through the workqueue.
  32  */
  33 struct xmit_work {
  34         struct sk_buff *skb;
  35         struct work_struct work;
  36         struct mac802154_priv *priv;
  37         u8 chan;
  38         u8 page;
  39 };
  40
  41 static void mac802154_xmit_worker(struct work_struct *work)
  42 {
  43         struct xmit_work *xw = container_of(work, struct xmit_work, work);
  44         struct mac802154_sub_if_data *sdata;
  45         int res;
  46
  47         mutex_lock(&xw->priv->phy->pib_lock);
  48         if (xw->priv->phy->current_channel != xw->chan ||
  49             xw->priv->phy->current_page != xw->page) {
  50                 res = xw->priv->ops->set_channel(&xw->priv->hw,
  51                                                   xw->page,
  52                                                   xw->chan);
  53                 if (res) {
  54                         pr_debug("set_channel failed\n");
  55                         goto out;
  56                 }
  57
  58                 xw->priv->phy->current_channel = xw->chan;
  59                 xw->priv->phy->current_page = xw->page;
  60         }
  61
  62         res = xw->priv->ops->xmit(&xw->priv->hw, xw->skb);
  63         if (res)
  64                 pr_debug("transmission failed\n");
  65
  66 out:
  67         mutex_unlock(&xw->priv->phy->pib_lock);
  68
  69         /* Restart the netif queue on each sub_if_data object. */
  70         rcu_read_lock();
  71         list_for_each_entry_rcu(sdata, &xw->priv->slaves, list)
  72                 netif_wake_queue(sdata->dev);
  73         rcu_read_unlock();
  74
  75         dev_kfree_skb(xw->skb);
  76
  77         kfree(xw);
  78 }
  79
  80 netdev_tx_t mac802154_tx(struct mac802154_priv *priv, struct sk_buff *skb,
  81                          u8 page, u8 chan)
  82 {
  83         struct xmit_work *work;
  84         struct mac802154_sub_if_data *sdata;
  85
  86         if (!(priv->phy->channels_supported[page] & (1 << chan))) {
  87                 WARN_ON(1);
  88                 goto err_tx;
  89         }
  90
  91         mac802154_monitors_rx(mac802154_to_priv(&priv->hw), skb);
  92
  93         if (!(priv->hw.flags & IEEE802154_HW_OMIT_CKSUM)) {
  94                 u16 crc = crc_ccitt(0, skb->data, skb->len);
  95                 u8 *data = skb_put(skb, 2);
  96
  97                 data[0] = crc & 0xff;
  98                 data[1] = crc >> 8;
  99         }
 100
 101         if (skb_cow_head(skb, priv->hw.extra_tx_headroom))
 102                 goto err_tx;
 103
 104         work = kzalloc(sizeof(*work), GFP_ATOMIC);
 105         if (!work) {
 106                 kfree_skb(skb);
 107                 return NETDEV_TX_BUSY;
 108         }
 109
 110         /* Stop the netif queue on each sub_if_data object. */
 111         rcu_read_lock();
 112         list_for_each_entry_rcu(sdata, &priv->slaves, list)
 113                 netif_stop_queue(sdata->dev);
 114         rcu_read_unlock();
 115
 116         INIT_WORK(&work->work, mac802154_xmit_worker);
 117         work->skb = skb;
 118         work->priv = priv;
 119         work->page = page;
 120         work->chan = chan;
 121
 122         queue_work(priv->dev_workqueue, &work->work);
 123
 124         return NETDEV_TX_OK;
 125
 126 err_tx:
 127         kfree_skb(skb);
 128         return NETDEV_TX_OK;
 129 }