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/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  */
  36 struct 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
  45 static 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
  64 out:
  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
  81 netdev_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                 return NETDEV_TX_OK;
  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                 data[0] = crc & 0xff;
  97                 data[1] = crc >> 8;
  98         }
  99
 100         if (skb_cow_head(skb, priv->hw.extra_tx_headroom)) {
 101                 dev_kfree_skb(skb);
 102                 return NETDEV_TX_OK;
 103         }
 104
 105         work = kzalloc(sizeof(struct xmit_work), GFP_ATOMIC);
 106         if (!work)
 107                 return NETDEV_TX_BUSY;
 108
 109         INIT_WORK(&work->work, mac802154_xmit_worker);
 110         work->skb = skb;
 111         work->priv = priv;
 112         work->page = page;
 113         work->chan = chan;
 114         work->xmit_attempts = 0;
 115
 116         queue_work(priv->dev_workqueue, &work->work);
 117
 118         return NETDEV_TX_OK;
 119 }