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 */
 36struct 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
 45static 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
 64out:
 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
 81netdev_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	if (!(priv->hw.flags & IEEE802154_HW_OMIT_CKSUM)) {
 92		u16 crc = crc_ccitt(0, skb->data, skb->len);
 93		u8 *data = skb_put(skb, 2);
 94		data[0] = crc & 0xff;
 95		data[1] = crc >> 8;
 96	}
 97
 98	if (skb_cow_head(skb, priv->hw.extra_tx_headroom)) {
 99		dev_kfree_skb(skb);
100		return NETDEV_TX_OK;
101	}
102
103	work = kzalloc(sizeof(struct xmit_work), GFP_ATOMIC);
104	if (!work)
105		return NETDEV_TX_BUSY;
106
107	INIT_WORK(&work->work, mac802154_xmit_worker);
108	work->skb = skb;
109	work->priv = priv;
110	work->page = page;
111	work->chan = chan;
112	work->xmit_attempts = 0;
113
114	queue_work(priv->dev_workqueue, &work->work);
115
116	return NETDEV_TX_OK;
117}