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  */
  37 struct 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
  45 static 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
  70 out:
  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
  84 netdev_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 }