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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 <[email protected]>
19  * Sergey Lapin <[email protected]>
20  * Maxim Gorbachyov <[email protected]>
21  * Alexander Smirnov <[email protected]>
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;
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) {
69  queue_work(xw->priv->dev_workqueue, &xw->work);
70  return;
71  } else
72  pr_debug("transmission failed for %d times",
74  }
75 
76  dev_kfree_skb(xw->skb);
77 
78  kfree(xw);
79 }
80 
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 
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 }