path: root/drivers/net/wireless/rt2x00/rt2x00mac.c

/*
	Copyright (C) 2004 - 2008 rt2x00 SourceForge Project
	<http://rt2x00.serialmonkey.com>

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the
	Free Software Foundation, Inc.,
	59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*
	Module: rt2x00mac
	Abstract: rt2x00 generic mac80211 routines.
 */

#include <linux/kernel.h>
#include <linux/module.h>

#include "rt2x00.h"
#include "rt2x00lib.h"

static int rt2x00mac_tx_rts_cts(struct rt2x00_dev *rt2x00dev,
				struct data_queue *queue,
				struct sk_buff *frag_skb,
				struct ieee80211_tx_control *control)
{
	struct skb_frame_desc *skbdesc;
	struct sk_buff *skb;
	int size;

	if (control->flags & IEEE80211_TXCTL_USE_CTS_PROTECT)
		size = sizeof(struct ieee80211_cts);
	else
		size = sizeof(struct ieee80211_rts);

	skb = dev_alloc_skb(size + rt2x00dev->hw->extra_tx_headroom);
	if (!skb) {
		WARNING(rt2x00dev, "Failed to create RTS/CTS frame.\n");
		return NETDEV_TX_BUSY;
	}

	skb_reserve(skb, rt2x00dev->hw->extra_tx_headroom);
	skb_put(skb, size);

	if (control->flags & IEEE80211_TXCTL_USE_CTS_PROTECT)
		ieee80211_ctstoself_get(rt2x00dev->hw, control->vif,
					frag_skb->data, frag_skb->len, control,
					(struct ieee80211_cts *)(skb->data));
	else
		ieee80211_rts_get(rt2x00dev->hw, control->vif,
				  frag_skb->data, frag_skb->len, control,
				  (struct ieee80211_rts *)(skb->data));

	/*
	 * Initialize skb descriptor
	 */
	skbdesc = get_skb_frame_desc(skb);
	memset(skbdesc, 0, sizeof(*skbdesc));
	skbdesc->flags |= FRAME_DESC_DRIVER_GENERATED;

	if (rt2x00dev->ops->lib->write_tx_data(rt2x00dev, queue, skb, control)) {
		WARNING(rt2x00dev, "Failed to send RTS/CTS frame.\n");
		return NETDEV_TX_BUSY;
	}

	return NETDEV_TX_OK;
}

int rt2x00mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb,
		 struct ieee80211_tx_control *control)
{
	struct rt2x00_dev *rt2x00dev = hw->priv;
	struct ieee80211_hdr *ieee80211hdr = (struct ieee80211_hdr *)skb->data;
	struct data_queue *queue;
	struct skb_frame_desc *skbdesc;
	u16 frame_control;

	/*
	 * Mac80211 might be calling this function while we are trying
	 * to remove the device or perhaps suspending it.
	 * Note that we can only stop the TX queues inside the TX path
	 * due to possible race conditions in mac80211.
	 */
	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags)) {
		ieee80211_stop_queues(hw);
		return NETDEV_TX_OK;
	}

	/*
	 * Determine which queue to put packet on.
	 */
	if (control->flags & IEEE80211_TXCTL_SEND_AFTER_DTIM &&
	    test_bit(DRIVER_REQUIRE_ATIM_QUEUE, &rt2x00dev->flags))
		queue = rt2x00queue_get_queue(rt2x00dev, RT2X00_BCN_QUEUE_ATIM);
	else
		queue = rt2x00queue_get_queue(rt2x00dev, control->queue);
	if (unlikely(!queue)) {
		ERROR(rt2x00dev,
		      "Attempt to send packet over invalid queue %d.\n"
		      "Please file bug report to %s.\n",
		      control->queue, DRV_PROJECT);
		dev_kfree_skb_any(skb);
		return NETDEV_TX_OK;
	}

	/*
	 * If CTS/RTS is required. and this frame is not CTS or RTS,
	 * create and queue that frame first. But make sure we have
	 * at least enough entries available to send this CTS/RTS
	 * frame as well as the data frame.
	 */
	frame_control = le16_to_cpu(ieee80211hdr->frame_control);
	if (!is_rts_frame(frame_control) && !is_cts_frame(frame_control) &&
	    (control->flags & (IEEE80211_TXCTL_USE_RTS_CTS |
			       IEEE80211_TXCTL_USE_CTS_PROTECT))) {
		if (rt2x00queue_available(queue) <= 1) {
			ieee80211_stop_queue(rt2x00dev->hw, control->queue);
			return NETDEV_TX_BUSY;
		}

		if (rt2x00mac_tx_rts_cts(rt2x00dev, queue, skb, control)) {
			ieee80211_stop_queue(rt2x00dev->hw, control->queue);
			return NETDEV_TX_BUSY;
		}
	}

	/*
	 * Initialize skb descriptor
	 */
	skbdesc = get_skb_frame_desc(skb);
	memset(skbdesc, 0, sizeof(*skbdesc));

	if (rt2x00dev->ops->lib->write_tx_data(rt2x00dev, queue, skb, control)) {
		ieee80211_stop_queue(rt2x00dev->hw, control->queue);
		return NETDEV_TX_BUSY;
	}

	if (rt2x00queue_full(queue))
		ieee80211_stop_queue(rt2x00dev->hw, control->queue);

	if (rt2x00dev->ops->lib->kick_tx_queue)
		rt2x00dev->ops->lib->kick_tx_queue(rt2x00dev, control->queue);

	return NETDEV_TX_OK;
}
EXPORT_SYMBOL_GPL(rt2x00mac_tx);

int rt2x00mac_start(struct ieee80211_hw *hw)
{
	struct rt2x00_dev *rt2x00dev = hw->priv;

	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags))
		return 0;

	return rt2x00lib_start(rt2x00dev);
}
EXPORT_SYMBOL_GPL(rt2x00mac_start);

void rt2x00mac_stop(struct ieee80211_hw *hw)
{
	struct rt2x00_dev *rt2x00dev = hw->priv;

	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags))
		return;

	rt2x00lib_stop(rt2x00dev);
}
EXPORT_SYMBOL_GPL(rt2x00mac_stop);

int rt2x00mac_add_interface(struct ieee80211_hw *hw,
			    struct ieee80211_if_init_conf *conf)
{
	struct rt2x00_dev *rt2x00dev = hw->priv;
	struct rt2x00_intf *intf = vif_to_intf(conf->vif);
	struct data_queue *queue =
	    rt2x00queue_get_queue(rt2x00dev, RT2X00_BCN_QUEUE_BEACON);
	struct queue_entry *entry = NULL;
	unsigned int i;

	/*
	 * Don't allow interfaces to be added
	 * the device has disappeared.
	 */
	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags) ||
	    !test_bit(DEVICE_STARTED, &rt2x00dev->flags))
		return -ENODEV;

	/*
	 * When we don't support mixed interfaces (a combination
	 * of sta and ap virtual interfaces) then we can only
	 * add this interface when the rival interface count is 0.
	 */
	if (!test_bit(DRIVER_SUPPORT_MIXED_INTERFACES, &rt2x00dev->flags) &&
	    ((conf->type == IEEE80211_IF_TYPE_AP && rt2x00dev->intf_sta_count) ||
	     (conf->type != IEEE80211_IF_TYPE_AP && rt2x00dev->intf_ap_count)))
		return -ENOBUFS;

	/*
	 * Check if we exceeded the maximum amount of supported interfaces.
	 */
	if ((conf->type == IEEE80211_IF_TYPE_AP &&
	     rt2x00dev->intf_ap_count >= rt2x00dev->ops->max_ap_intf) ||
	    (conf->type != IEEE80211_IF_TYPE_AP &&
	     rt2x00dev->intf_sta_count >= rt2x00dev->ops->max_sta_intf))
		return -ENOBUFS;

	/*
	 * Loop through all beacon queues to find a free
	 * entry. Since there are as much beacon entries
	 * as the maximum interfaces, this search shouldn't
	 * fail.
	 */
	for (i = 0; i < queue->limit; i++) {
		entry = &queue->entries[i];
		if (!__test_and_set_bit(ENTRY_BCN_ASSIGNED, &entry->flags))
			break;
	}

	if (unlikely(i == queue->limit))
		return -ENOBUFS;

	/*
	 * We are now absolutely sure the interface can be created,
	 * increase interface count and start initialization.
	 */

	if (conf->type == IEEE80211_IF_TYPE_AP)
		rt2x00dev->intf_ap_count++;
	else
		rt2x00dev->intf_sta_count++;

	spin_lock_init(&intf