linux/drivers/net/wireless/wl12xx/wl1271_tx.c - nest-guard/1.0/linux - Git at Google

 /*
  * This file is part of wl1271
  *
  * Copyright (C) 2009 Nokia Corporation
  *
  * Contact: Luciano Coelho <luciano.coelho@nokia.com>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * version 2 as published by the Free Software Foundation.
  *
  * 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., 51 Franklin St, Fifth Floor, Boston, MA
  * 02110-1301 USA
  *
  */

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

 #include "wl1271.h"
 #include "wl1271_io.h"
 #include "wl1271_reg.h"
 #include "wl1271_ps.h"
 #include "wl1271_tx.h"

 static int wl1271_tx_id(struct wl1271 *wl, struct sk_buff *skb)
 {
 	int i;
 	for (i = 0; i < ACX_TX_DESCRIPTORS; i++)
 		if (wl->tx_frames[i] == NULL) {
 			wl->tx_frames[i] = skb;
 			wl->tx_frames_cnt++;
 			return i;
 		}

 	return -EBUSY;
 }

 static int wl1271_tx_allocate(struct wl1271 *wl, struct sk_buff *skb, u32 extra,
 				u32 buf_offset)
 {
 	struct wl1271_tx_hw_descr *desc;
 	u32 total_len = skb->len + sizeof(struct wl1271_tx_hw_descr) + extra;
 	u32 total_blocks;
 	int id, ret = -EBUSY;

 	if (buf_offset + total_len > WL1271_AGGR_BUFFER_SIZE)
 		return -EBUSY;

 	/* allocate free identifier for the packet */
 	id = wl1271_tx_id(wl, skb);
 	if (id < 0)
 		return id;

 	/* approximate the number of blocks required for this packet
 	   in the firmware */
 	total_blocks = total_len + TX_HW_BLOCK_SIZE - 1;
 	total_blocks = total_blocks / TX_HW_BLOCK_SIZE + TX_HW_BLOCK_SPARE;
 	if (total_blocks <= wl->tx_blocks_available) {
 		desc = (struct wl1271_tx_hw_descr *)skb_push(
 			skb, total_len - skb->len);

 		desc->extra_mem_blocks = TX_HW_BLOCK_SPARE;
 		desc->total_mem_blocks = total_blocks;
 		desc->id = id;

 		wl->tx_blocks_available -= total_blocks;

 		ret = 0;

 		wl1271_debug(DEBUG_TX,
 			     "tx_allocate: size: %d, blocks: %d, id: %d",
 			     total_len, total_blocks, id);
 	} else {
 		wl->tx_frames[id] = NULL;
 		wl->tx_frames_cnt--;
 	}

 	return ret;
 }

 static void wl1271_tx_fill_hdr(struct wl1271 *wl, struct sk_buff *skb,
 			      u32 extra, struct ieee80211_tx_info *control)
 {
 	struct timespec ts;
 	struct wl1271_tx_hw_descr *desc;
 	int pad, ac;
 	s64 hosttime;
 	u16 tx_attr;

 	desc = (struct wl1271_tx_hw_descr *) skb->data;

 	/* relocate space for security header */
 	if (extra) {
 		void *framestart = skb->data + sizeof(*desc);
 		u16 fc = *(u16 *)(framestart + extra);
 		int hdrlen = ieee80211_hdrlen(cpu_to_le16(fc));
 		memmove(framestart, framestart + extra, hdrlen);
 	}

 	/* configure packet life time */
 	getnstimeofday(&ts);
 	hosttime = (timespec_to_ns(&ts) >> 10);
 	desc->start_time = cpu_to_le32(hosttime - wl->time_offset);
 	desc->life_time = cpu_to_le16(TX_HW_MGMT_PKT_LIFETIME_TU);

 	/* configure the tx attributes */
 	tx_attr = wl->session_counter << TX_HW_ATTR_OFST_SESSION_COUNTER;

 	/* queue (we use same identifiers for tid's and ac's */
 	ac = wl1271_tx_get_queue(skb_get_queue_mapping(skb));
 	desc->tid = ac;

 	desc->aid = TX_HW_DEFAULT_AID;
 	desc->reserved = 0;

 	/* align the length (and store in terms of words) */
 	pad = WL1271_TX_ALIGN(skb->len);
 	desc->length = cpu_to_le16(pad >> 2);

 	/* calculate number of padding bytes */
 	pad = pad - skb->len;
 	tx_attr |= pad << TX_HW_ATTR_OFST_LAST_WORD_PAD;

 	/* if the packets are destined for AP (have a STA entry) send them
 	   with AP rate policies, otherwise use default basic rates */
 	if (control->control.sta)
 		tx_attr |= ACX_TX_AP_FULL_RATE << TX_HW_ATTR_OFST_RATE_POLICY;

 	desc->tx_attr = cpu_to_le16(tx_attr);

 	wl1271_debug(DEBUG_TX, "tx_fill_hdr: pad: %d", pad);
 }

 /* caller must hold wl->mutex */
 static int wl1271_prepare_tx_frame(struct wl1271 *wl, struct sk_buff *skb,
 							u32 buf_offset)
 {
 	struct ieee80211_tx_info *info;
 	u32 extra = 0;
 	int ret = 0;
 	u8 idx;
 	u32 total_len;

 	if (!skb)
 		return -EINVAL;

 	info = IEEE80211_SKB_CB(skb);

 	if (info->control.hw_key &&
 	    info->control.hw_key->cipher == WLAN_CIPHER_SUITE_TKIP)
 		extra = WL1271_TKIP_IV_SPACE;

 	if (info->control.hw_key) {
 		idx = info->control.hw_key->hw_key_idx;

 		/* FIXME: do we have to do this if we're not using WEP? */
 		if (unlikely(wl->default_key != idx)) {
 			ret = wl1271_cmd_set_default_wep_key(wl, idx);
 			if (ret < 0)
 				return ret;
 			wl->default_key = idx;
 		}
 	}

 	ret = wl1271_tx_allocate(wl, skb, extra, buf_offset);
 	if (ret < 0)
 		return ret;

 	wl1271_tx_fill_hdr(wl, skb, extra, info);

 	/*
 	 * The length of each packet is stored in terms of words. Thus, we must
 	 * pad the skb data to make sure its length is aligned.
 	 * The number of padding bytes is computed and set in wl1271_tx_fill_hdr
 	 */
 	total_len = WL1271_TX_ALIGN(skb->len);
 	memcpy(wl->aggr_buf + buf_offset, skb->data, skb->len);
 	memset(wl->aggr_buf + buf_offset + skb->len, 0, total_len - skb->len);

 	return total_len;
 }

 u32 wl1271_tx_enabled_rates_get(struct wl1271 *wl, u32 rate_set)
 {
 	struct ieee80211_supported_band *band;
 	u32 enabled_rates = 0;
 	int bit;

 	band = wl->hw->wiphy->bands[wl->band];
 	for (bit = 0; bit < band->n_bitrates; bit++) {
 		if (rate_set & 0x1)
 			enabled_rates |= band->bitrates[bit].hw_value;
 		rate_set >>= 1;
 	}

 	return enabled_rates;
 }

 void wl1271_tx_work(struct work_struct *work)
 {
 	struct wl1271 *wl = container_of(work, struct wl1271, tx_work);
 	struct sk_buff *skb;
 	bool woken_up = false;
 	u32 sta_rates = 0;
 	u32 buf_offset;
 	int ret;

 	/* check if the rates supported by the AP have changed */
 	if (unlikely(test_and_clear_bit(WL1271_FLAG_STA_RATES_CHANGED,
 					&wl->flags))) {
 		unsigned long flags;
 		spin_lock_irqsave(&wl->wl_lock, flags);
 		sta_rates = wl->sta_rate_set;
 		spin_unlock_irqrestore(&wl->wl_lock, flags);
 	}

 	mutex_lock(&wl->mutex);

 	if (unlikely(wl->state == WL1271_STATE_OFF))
 		goto out;

 	/* if rates have changed, re-configure the rate policy */
 	if (unlikely(sta_rates)) {
 		wl->rate_set = wl1271_tx_enabled_rates_get(wl, sta_rates);
 		wl1271_acx_rate_policies(wl);
 	}

 	/* Prepare the transfer buffer, by aggregating all
 	 * available packets */
 	buf_offset = 0;
 	while ((skb = skb_dequeue(&wl->tx_queue))) {
 		if (!woken_up) {
 			ret = wl1271_ps_elp_wakeup(wl, false);
 			if (ret < 0)
 				goto out_ack;
 			woken_up = true;
 		}

 		ret = wl1271_prepare_tx_frame(wl, skb, buf_offset);
 		if (ret == -EBUSY) {
 			/*
 			 * Either the firmware buffer is full, or the
 			 * aggregation buffer is.
 			 * Queue back last skb, and stop aggregating.
 			 */
 			skb_queue_head(&wl->tx_queue, skb);
 			goto out_ack;
 		} else if (ret < 0) {
 			dev_kfree_skb(skb);
 			goto out_ack;
 		}
 		buf_offset += ret;
 		wl->tx_packets_count++;
 	}

 out_ack:
 	if (buf_offset) {
 		wl1271_write(wl, WL1271_SLV_MEM_DATA, wl->aggr_buf,
 				buf_offset, true);
 		/* interrupt the firmware with the new packets */
 		wl1271_write32(wl, WL1271_HOST_WR_ACCESS, wl->tx_packets_count);
 	}

 out:
 	if (woken_up)
 		wl1271_ps_elp_sleep(wl);

 	mutex_unlock(&wl->mutex);
 }

 static void wl1271_tx_complete_packet(struct wl1271 *wl,
 				      struct wl1271_tx_hw_res_descr *result)
 {
 	struct ieee80211_tx_info *info;
 	struct sk_buff *skb;
 	int id = result->id;
 	int rate = -1;
 	u8 retries = 0;

 	/* check for id legality */
 	if (unlikely(id >= ACX_TX_DESCRIPTORS || wl->tx_frames[id] == NULL)) {
 		wl1271_warning("TX result illegal id: %d", id);
 		return;
 	}

 	skb = wl->tx_frames[id];
 	info = IEEE80211_SKB_CB(skb);

 	/* update the TX status info */
 	if (result->status == TX_SUCCESS) {
 		if (!(info->flags & IEEE80211_TX_CTL_NO_ACK))
 			info->flags |= IEEE80211_TX_STAT_ACK;
 		rate = wl1271_rate_to_idx(wl, result->rate_class_index);
 		retries = result->ack_failures;
 	} else if (result->status == TX_RETRY_EXCEEDED) {
 		wl->stats.excessive_retries++;
 		retries = result->ack_failures;
 	}

 	info->status.rates[0].idx = rate;
 	info->status.rates[0].count = retries;
 	info->status.rates[0].flags = 0;
 	info->status.ack_signal = -1;

 	wl->stats.retry_count += result->ack_failures;

 	/* update security sequence number */
 	wl->tx_security_seq += (result->lsb_security_sequence_number -
 				wl->tx_security_last_seq);
 	wl->tx_security_last_seq = result->lsb_security_sequence_number;

 	/* remove private header from packet */
 	skb_pull(skb, sizeof(struct wl1271_tx_hw_descr));

 	/* remove TKIP header space if present */
 	if (info->control.hw_key &&
 	    info->control.hw_key->cipher == WLAN_CIPHER_SUITE_TKIP) {
 		int hdrlen = ieee80211_get_hdrlen_from_skb(skb);
 		memmove(skb->data + WL1271_TKIP_IV_SPACE, skb->data, hdrlen);
 		skb_pull(skb, WL1271_TKIP_IV_SPACE);
 	}

 	wl1271_debug(DEBUG_TX, "tx status id %u skb 0x%p failures %u rate 0x%x"
 		     " status 0x%x",
 		     result->id, skb, result->ack_failures,
 		     result->rate_class_index, result->status);

 	/* return the packet to the stack */
 	ieee80211_tx_status(wl->hw, skb);
 	wl->tx_frames[result->id] = NULL;
 	wl->tx_frames_cnt--;
 }

 /* Called upon reception of a TX complete interrupt */
 void wl1271_tx_complete(struct wl1271 *wl)
 {
 	struct wl1271_acx_mem_map *memmap =
 		(struct wl1271_acx_mem_map *)wl->target_mem_map;
 	u32 count, fw_counter;
 	u32 i;

 	/* read the tx results from the chipset */
 	wl1271_read(wl, le32_to_cpu(memmap->tx_result),
 		    wl->tx_res_if, sizeof(*wl->tx_res_if), false);
 	fw_counter = le32_to_cpu(wl->tx_res_if->tx_result_fw_counter);

 	/* write host counter to chipset (to ack) */
 	wl1271_write32(wl, le32_to_cpu(memmap->tx_result) +
 		       offsetof(struct wl1271_tx_hw_res_if,
 				tx_result_host_counter), fw_counter);

 	count = fw_counter - wl->tx_results_count;
 	wl1271_debug(DEBUG_TX, "tx_complete received, packets: %d", count);

 	/* verify that the result buffer is not getting overrun */
 	if (unlikely(count > TX_HW_RESULT_QUEUE_LEN))
 		wl1271_warning("TX result overflow from chipset: %d", count);

 	/* process the results */
 	for (i = 0; i < count; i++) {
 		struct wl1271_tx_hw_res_descr *result;
 		u8 offset = wl->tx_results_count & TX_HW_RESULT_QUEUE_LEN_MASK;

 		/* process the packet */
 		result =  &(wl->tx_res_if->tx_results_queue[offset]);
 		wl1271_tx_complete_packet(wl, result);

 		wl->tx_results_count++;
 	}

 	if (test_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags) &&
 	    skb_queue_len(&wl->tx_queue) <= WL1271_TX_QUEUE_LOW_WATERMARK) {
 		unsigned long flags;

 		/* firmware buffer has space, restart queues */
 		wl1271_debug(DEBUG_TX, "tx_complete: waking queues");
 		spin_lock_irqsave(&wl->wl_lock, flags);
 		ieee80211_wake_queues(wl->hw);
 		clear_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);
 		spin_unlock_irqrestore(&wl->wl_lock, flags);
 		ieee80211_queue_work(wl->hw, &wl->tx_work);
 	}
 }

 /* caller must hold wl->mutex */
 void wl1271_tx_reset(struct wl1271 *wl)
 {
 	int i;
 	struct sk_buff *skb;

 	/* TX failure */
 	while ((skb = skb_dequeue(&wl->tx_queue))) {
 		wl1271_debug(DEBUG_TX, "freeing skb 0x%p", skb);
 		ieee80211_tx_status(wl->hw, skb);
 	}

 	for (i = 0; i < ACX_TX_DESCRIPTORS; i++)
 		if (wl->tx_frames[i] != NULL) {
 			skb = wl->tx_frames[i];
 			wl->tx_frames[i] = NULL;
 			wl1271_debug(DEBUG_TX, "freeing skb 0x%p", skb);
 			ieee80211_tx_status(wl->hw, skb);
 		}
 	wl->tx_frames_cnt = 0;
 }

 #define WL1271_TX_FLUSH_TIMEOUT 500000

 /* caller must *NOT* hold wl->mutex */
 void wl1271_tx_flush(struct wl1271 *wl)
 {
 	unsigned long timeout;
 	timeout = jiffies + usecs_to_jiffies(WL1271_TX_FLUSH_TIMEOUT);

 	while (!time_after(jiffies, timeout)) {
 		mutex_lock(&wl->mutex);
 		wl1271_debug(DEBUG_TX, "flushing tx buffer: %d",
 			     wl->tx_frames_cnt);
 		if ((wl->tx_frames_cnt == 0) &&
 		    skb_queue_empty(&wl->tx_queue)) {
 			mutex_unlock(&wl->mutex);
 			return;
 		}
 		mutex_unlock(&wl->mutex);
 		msleep(1);
 	}

 	wl1271_warning("Unable to flush all TX buffers, timed out.");
 }
	/*
	* This file is part of wl1271
	*
	* Copyright (C) 2009 Nokia Corporation
	*
	* Contact: Luciano Coelho <luciano.coelho@nokia.com>
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* version 2 as published by the Free Software Foundation.
	*
	* 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., 51 Franklin St, Fifth Floor, Boston, MA
	* 02110-1301 USA
	*
	*/

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

	#include "wl1271.h"
	#include "wl1271_io.h"
	#include "wl1271_reg.h"
	#include "wl1271_ps.h"
	#include "wl1271_tx.h"

	static int wl1271_tx_id(struct wl1271 wl, struct sk_buff skb)
	{
	int i;
	for (i = 0; i < ACX_TX_DESCRIPTORS; i++)
	if (wl->tx_frames[i] == NULL) {
	wl->tx_frames[i] = skb;
	wl->tx_frames_cnt++;
	return i;
	}

	return -EBUSY;
	}

	static int wl1271_tx_allocate(struct wl1271 wl, struct sk_buff skb, u32 extra,
	u32 buf_offset)
	{
	struct wl1271_tx_hw_descr *desc;
	u32 total_len = skb->len + sizeof(struct wl1271_tx_hw_descr) + extra;
	u32 total_blocks;
	int id, ret = -EBUSY;

	if (buf_offset + total_len > WL1271_AGGR_BUFFER_SIZE)
	return -EBUSY;

	/* allocate free identifier for the packet */
	id = wl1271_tx_id(wl, skb);
	if (id < 0)
	return id;

	/* approximate the number of blocks required for this packet
	in the firmware */
	total_blocks = total_len + TX_HW_BLOCK_SIZE - 1;
	total_blocks = total_blocks / TX_HW_BLOCK_SIZE + TX_HW_BLOCK_SPARE;
	if (total_blocks <= wl->tx_blocks_available) {
	desc = (struct wl1271_tx_hw_descr *)skb_push(
	skb, total_len - skb->len);

	desc->extra_mem_blocks = TX_HW_BLOCK_SPARE;
	desc->total_mem_blocks = total_blocks;
	desc->id = id;

	wl->tx_blocks_available -= total_blocks;

	ret = 0;

	wl1271_debug(DEBUG_TX,
	"tx_allocate: size: %d, blocks: %d, id: %d",
	total_len, total_blocks, id);
	} else {
	wl->tx_frames[id] = NULL;
	wl->tx_frames_cnt--;
	}

	return ret;
	}

	static void wl1271_tx_fill_hdr(struct wl1271 wl, struct sk_buff skb,
	u32 extra, struct ieee80211_tx_info *control)
	{
	struct timespec ts;
	struct wl1271_tx_hw_descr *desc;
	int pad, ac;
	s64 hosttime;
	u16 tx_attr;

	desc = (struct wl1271_tx_hw_descr *) skb->data;

	/* relocate space for security header */
	if (extra) {
	void framestart = skb->data + sizeof(desc);
	u16 fc = (u16 )(framestart + extra);
	int hdrlen = ieee80211_hdrlen(cpu_to_le16(fc));
	memmove(framestart, framestart + extra, hdrlen);
	}

	/* configure packet life time */
	getnstimeofday(&ts);
	hosttime = (timespec_to_ns(&ts) >> 10);
	desc->start_time = cpu_to_le32(hosttime - wl->time_offset);
	desc->life_time = cpu_to_le16(TX_HW_MGMT_PKT_LIFETIME_TU);

	/* configure the tx attributes */
	tx_attr = wl->session_counter << TX_HW_ATTR_OFST_SESSION_COUNTER;

	/* queue (we use same identifiers for tid's and ac's */
	ac = wl1271_tx_get_queue(skb_get_queue_mapping(skb));
	desc->tid = ac;

	desc->aid = TX_HW_DEFAULT_AID;
	desc->reserved = 0;

	/* align the length (and store in terms of words) */
	pad = WL1271_TX_ALIGN(skb->len);
	desc->length = cpu_to_le16(pad >> 2);

	/* calculate number of padding bytes */
	pad = pad - skb->len;
	tx_attr \|= pad << TX_HW_ATTR_OFST_LAST_WORD_PAD;

	/* if the packets are destined for AP (have a STA entry) send them
	with AP rate policies, otherwise use default basic rates */
	if (control->control.sta)
	tx_attr \|= ACX_TX_AP_FULL_RATE << TX_HW_ATTR_OFST_RATE_POLICY;

	desc->tx_attr = cpu_to_le16(tx_attr);

	wl1271_debug(DEBUG_TX, "tx_fill_hdr: pad: %d", pad);
	}

	/* caller must hold wl->mutex */
	static int wl1271_prepare_tx_frame(struct wl1271 wl, struct sk_buff skb,
	u32 buf_offset)
	{
	struct ieee80211_tx_info *info;
	u32 extra = 0;
	int ret = 0;
	u8 idx;
	u32 total_len;

	if (!skb)
	return -EINVAL;

	info = IEEE80211_SKB_CB(skb);

	if (info->control.hw_key &&
	info->control.hw_key->cipher == WLAN_CIPHER_SUITE_TKIP)
	extra = WL1271_TKIP_IV_SPACE;

	if (info->control.hw_key) {
	idx = info->control.hw_key->hw_key_idx;

	/* FIXME: do we have to do this if we're not using WEP? */
	if (unlikely(wl->default_key != idx)) {
	ret = wl1271_cmd_set_default_wep_key(wl, idx);
	if (ret < 0)
	return ret;
	wl->default_key = idx;
	}
	}

	ret = wl1271_tx_allocate(wl, skb, extra, buf_offset);
	if (ret < 0)
	return ret;

	wl1271_tx_fill_hdr(wl, skb, extra, info);

	/*
	* The length of each packet is stored in terms of words. Thus, we must
	* pad the skb data to make sure its length is aligned.
	* The number of padding bytes is computed and set in wl1271_tx_fill_hdr
	*/
	total_len = WL1271_TX_ALIGN(skb->len);
	memcpy(wl->aggr_buf + buf_offset, skb->data, skb->len);
	memset(wl->aggr_buf + buf_offset + skb->len, 0, total_len - skb->len);

	return total_len;
	}

	u32 wl1271_tx_enabled_rates_get(struct wl1271 *wl, u32 rate_set)
	{
	struct ieee80211_supported_band *band;
	u32 enabled_rates = 0;
	int bit;

	band = wl->hw->wiphy->bands[wl->band];
	for (bit = 0; bit < band->n_bitrates; bit++) {
	if (rate_set & 0x1)
	enabled_rates \|= band->bitrates[bit].hw_value;
	rate_set >>= 1;
	}

	return enabled_rates;
	}

	void wl1271_tx_work(struct work_struct *work)
	{
	struct wl1271 *wl = container_of(work, struct wl1271, tx_work);
	struct sk_buff *skb;
	bool woken_up = false;
	u32 sta_rates = 0;
	u32 buf_offset;
	int ret;

	/* check if the rates supported by the AP have changed */
	if (unlikely(test_and_clear_bit(WL1271_FLAG_STA_RATES_CHANGED,
	&wl->flags))) {
	unsigned long flags;
	spin_lock_irqsave(&wl->wl_lock, flags);
	sta_rates = wl->sta_rate_set;
	spin_unlock_irqrestore(&wl->wl_lock, flags);
	}

	mutex_lock(&wl->mutex);

	if (unlikely(wl->state == WL1271_STATE_OFF))
	goto out;

	/* if rates have changed, re-configure the rate policy */
	if (unlikely(sta_rates)) {
	wl->rate_set = wl1271_tx_enabled_rates_get(wl, sta_rates);
	wl1271_acx_rate_policies(wl);
	}

	/* Prepare the transfer buffer, by aggregating all
	* available packets */
	buf_offset = 0;
	while ((skb = skb_dequeue(&wl->tx_queue))) {
	if (!woken_up) {
	ret = wl1271_ps_elp_wakeup(wl, false);
	if (ret < 0)
	goto out_ack;
	woken_up = true;
	}

	ret = wl1271_prepare_tx_frame(wl, skb, buf_offset);
	if (ret == -EBUSY) {
	/*
	* Either the firmware buffer is full, or the
	* aggregation buffer is.
	* Queue back last skb, and stop aggregating.
	*/
	skb_queue_head(&wl->tx_queue, skb);
	goto out_ack;
	} else if (ret < 0) {
	dev_kfree_skb(skb);
	goto out_ack;
	}
	buf_offset += ret;
	wl->tx_packets_count++;
	}

	out_ack:
	if (buf_offset) {
	wl1271_write(wl, WL1271_SLV_MEM_DATA, wl->aggr_buf,
	buf_offset, true);
	/* interrupt the firmware with the new packets */
	wl1271_write32(wl, WL1271_HOST_WR_ACCESS, wl->tx_packets_count);
	}

	out:
	if (woken_up)
	wl1271_ps_elp_sleep(wl);

	mutex_unlock(&wl->mutex);
	}

	static void wl1271_tx_complete_packet(struct wl1271 *wl,
	struct wl1271_tx_hw_res_descr *result)
	{
	struct ieee80211_tx_info *info;
	struct sk_buff *skb;
	int id = result->id;
	int rate = -1;
	u8 retries = 0;

	/* check for id legality */
	if (unlikely(id >= ACX_TX_DESCRIPTORS \|\| wl->tx_frames[id] == NULL)) {
	wl1271_warning("TX result illegal id: %d", id);
	return;
	}

	skb = wl->tx_frames[id];
	info = IEEE80211_SKB_CB(skb);

	/* update the TX status info */
	if (result->status == TX_SUCCESS) {
	if (!(info->flags & IEEE80211_TX_CTL_NO_ACK))
	info->flags \|= IEEE80211_TX_STAT_ACK;
	rate = wl1271_rate_to_idx(wl, result->rate_class_index);
	retries = result->ack_failures;
	} else if (result->status == TX_RETRY_EXCEEDED) {
	wl->stats.excessive_retries++;
	retries = result->ack_failures;
	}

	info->status.rates[0].idx = rate;
	info->status.rates[0].count = retries;
	info->status.rates[0].flags = 0;
	info->status.ack_signal = -1;

	wl->stats.retry_count += result->ack_failures;

	/* update security sequence number */
	wl->tx_security_seq += (result->lsb_security_sequence_number -
	wl->tx_security_last_seq);
	wl->tx_security_last_seq = result->lsb_security_sequence_number;

	/* remove private header from packet */
	skb_pull(skb, sizeof(struct wl1271_tx_hw_descr));

	/* remove TKIP header space if present */
	if (info->control.hw_key &&
	info->control.hw_key->cipher == WLAN_CIPHER_SUITE_TKIP) {
	int hdrlen = ieee80211_get_hdrlen_from_skb(skb);
	memmove(skb->data + WL1271_TKIP_IV_SPACE, skb->data, hdrlen);
	skb_pull(skb, WL1271_TKIP_IV_SPACE);
	}

	wl1271_debug(DEBUG_TX, "tx status id %u skb 0x%p failures %u rate 0x%x"
	" status 0x%x",
	result->id, skb, result->ack_failures,
	result->rate_class_index, result->status);

	/* return the packet to the stack */
	ieee80211_tx_status(wl->hw, skb);
	wl->tx_frames[result->id] = NULL;
	wl->tx_frames_cnt--;
	}

	/* Called upon reception of a TX complete interrupt */
	void wl1271_tx_complete(struct wl1271 *wl)
	{
	struct wl1271_acx_mem_map *memmap =
	(struct wl1271_acx_mem_map *)wl->target_mem_map;
	u32 count, fw_counter;
	u32 i;

	/* read the tx results from the chipset */
	wl1271_read(wl, le32_to_cpu(memmap->tx_result),
	wl->tx_res_if, sizeof(*wl->tx_res_if), false);
	fw_counter = le32_to_cpu(wl->tx_res_if->tx_result_fw_counter);

	/* write host counter to chipset (to ack) */
	wl1271_write32(wl, le32_to_cpu(memmap->tx_result) +
	offsetof(struct wl1271_tx_hw_res_if,
	tx_result_host_counter), fw_counter);

	count = fw_counter - wl->tx_results_count;
	wl1271_debug(DEBUG_TX, "tx_complete received, packets: %d", count);

	/* verify that the result buffer is not getting overrun */
	if (unlikely(count > TX_HW_RESULT_QUEUE_LEN))
	wl1271_warning("TX result overflow from chipset: %d", count);

	/* process the results */
	for (i = 0; i < count; i++) {
	struct wl1271_tx_hw_res_descr *result;
	u8 offset = wl->tx_results_count & TX_HW_RESULT_QUEUE_LEN_MASK;

	/* process the packet */
	result = &(wl->tx_res_if->tx_results_queue[offset]);
	wl1271_tx_complete_packet(wl, result);

	wl->tx_results_count++;
	}

	if (test_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags) &&
	skb_queue_len(&wl->tx_queue) <= WL1271_TX_QUEUE_LOW_WATERMARK) {
	unsigned long flags;

	/* firmware buffer has space, restart queues */
	wl1271_debug(DEBUG_TX, "tx_complete: waking queues");
	spin_lock_irqsave(&wl->wl_lock, flags);
	ieee80211_wake_queues(wl->hw);
	clear_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);
	spin_unlock_irqrestore(&wl->wl_lock, flags);
	ieee80211_queue_work(wl->hw, &wl->tx_work);
	}
	}

	/* caller must hold wl->mutex */
	void wl1271_tx_reset(struct wl1271 *wl)
	{
	int i;
	struct sk_buff *skb;

	/* TX failure */
	while ((skb = skb_dequeue(&wl->tx_queue))) {
	wl1271_debug(DEBUG_TX, "freeing skb 0x%p", skb);
	ieee80211_tx_status(wl->hw, skb);
	}

	for (i = 0; i < ACX_TX_DESCRIPTORS; i++)
	if (wl->tx_frames[i] != NULL) {
	skb = wl->tx_frames[i];
	wl->tx_frames[i] = NULL;
	wl1271_debug(DEBUG_TX, "freeing skb 0x%p", skb);
	ieee80211_tx_status(wl->hw, skb);
	}
	wl->tx_frames_cnt = 0;
	}

	#define WL1271_TX_FLUSH_TIMEOUT 500000

	/* caller must NOT hold wl->mutex */
	void wl1271_tx_flush(struct wl1271 *wl)
	{
	unsigned long timeout;
	timeout = jiffies + usecs_to_jiffies(WL1271_TX_FLUSH_TIMEOUT);

	while (!time_after(jiffies, timeout)) {
	mutex_lock(&wl->mutex);
	wl1271_debug(DEBUG_TX, "flushing tx buffer: %d",
	wl->tx_frames_cnt);
	if ((wl->tx_frames_cnt == 0) &&
	skb_queue_empty(&wl->tx_queue)) {
	mutex_unlock(&wl->mutex);
	return;
	}
	mutex_unlock(&wl->mutex);
	msleep(1);
	}

	wl1271_warning("Unable to flush all TX buffers, timed out.");
	}