drivers/net/wireless/wl1251/tx.c - android_kernel_htc_msm8960 - Gitiles

 /*
  * This file is part of wl1251
  *
  * Copyright (c) 1998-2007 Texas Instruments Incorporated
  * Copyright (C) 2008 Nokia Corporation
  *
  * 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 "wl1251.h"
 #include "reg.h"
 #include "tx.h"
 #include "ps.h"
 #include "io.h"

 static bool wl1251_tx_double_buffer_busy(struct wl1251 *wl, u32 data_out_count)
 {
 	int used, data_in_count;

 	data_in_count = wl->data_in_count;

 	if (data_in_count < data_out_count)
 		/* data_in_count has wrapped */
 		data_in_count += TX_STATUS_DATA_OUT_COUNT_MASK + 1;

 	used = data_in_count - data_out_count;

 	WARN_ON(used < 0);
 	WARN_ON(used > DP_TX_PACKET_RING_CHUNK_NUM);

 	if (used >= DP_TX_PACKET_RING_CHUNK_NUM)
 		return true;
 	else
 		return false;
 }

 static int wl1251_tx_path_status(struct wl1251 *wl)
 {
 	u32 status, addr, data_out_count;
 	bool busy;

 	addr = wl->data_path->tx_control_addr;
 	status = wl1251_mem_read32(wl, addr);
 	data_out_count = status & TX_STATUS_DATA_OUT_COUNT_MASK;
 	busy = wl1251_tx_double_buffer_busy(wl, data_out_count);

 	if (busy)
 		return -EBUSY;

 	return 0;
 }

 static int wl1251_tx_id(struct wl1251 *wl, struct sk_buff *skb)
 {
 	int i;

 	for (i = 0; i < FW_TX_CMPLT_BLOCK_SIZE; i++)
 		if (wl->tx_frames[i] == NULL) {
 			wl->tx_frames[i] = skb;
 			return i;
 		}

 	return -EBUSY;
 }

 static void wl1251_tx_control(struct tx_double_buffer_desc *tx_hdr,
 			      struct ieee80211_tx_info *control, u16 fc)
 {
 	*(u16 *)&tx_hdr->control = 0;

 	tx_hdr->control.rate_policy = 0;

 	/* 802.11 packets */
 	tx_hdr->control.packet_type = 0;

 	if (control->flags & IEEE80211_TX_CTL_NO_ACK)
 		tx_hdr->control.ack_policy = 1;

 	tx_hdr->control.tx_complete = 1;

 	if ((fc & IEEE80211_FTYPE_DATA) &&
 	    ((fc & IEEE80211_STYPE_QOS_DATA) ||
 	     (fc & IEEE80211_STYPE_QOS_NULLFUNC)))
 		tx_hdr->control.qos = 1;
 }

 /* RSN + MIC = 8 + 8 = 16 bytes (worst case - AES). */
 #define MAX_MSDU_SECURITY_LENGTH      16
 #define MAX_MPDU_SECURITY_LENGTH      16
 #define WLAN_QOS_HDR_LEN              26
 #define MAX_MPDU_HEADER_AND_SECURITY  (MAX_MPDU_SECURITY_LENGTH + \
 				       WLAN_QOS_HDR_LEN)
 #define HW_BLOCK_SIZE                 252
 static void wl1251_tx_frag_block_num(struct tx_double_buffer_desc *tx_hdr)
 {
 	u16 payload_len, frag_threshold, mem_blocks;
 	u16 num_mpdus, mem_blocks_per_frag;

 	frag_threshold = IEEE80211_MAX_FRAG_THRESHOLD;
 	tx_hdr->frag_threshold = cpu_to_le16(frag_threshold);

 	payload_len = le16_to_cpu(tx_hdr->length) + MAX_MSDU_SECURITY_LENGTH;

 	if (payload_len > frag_threshold) {
 		mem_blocks_per_frag =
 			((frag_threshold + MAX_MPDU_HEADER_AND_SECURITY) /
 			 HW_BLOCK_SIZE) + 1;
 		num_mpdus = payload_len / frag_threshold;
 		mem_blocks = num_mpdus * mem_blocks_per_frag;
 		payload_len -= num_mpdus * frag_threshold;
 		num_mpdus++;

 	} else {
 		mem_blocks_per_frag = 0;
 		mem_blocks = 0;
 		num_mpdus = 1;
 	}

 	mem_blocks += (payload_len / HW_BLOCK_SIZE) + 1;

 	if (num_mpdus > 1)
 		mem_blocks += min(num_mpdus, mem_blocks_per_frag);

 	tx_hdr->num_mem_blocks = mem_blocks;
 }

 static int wl1251_tx_fill_hdr(struct wl1251 *wl, struct sk_buff *skb,
 			      struct ieee80211_tx_info *control)
 {
 	struct tx_double_buffer_desc *tx_hdr;
 	struct ieee80211_rate *rate;
 	int id;
 	u16 fc;

 	if (!skb)
 		return -EINVAL;

 	id = wl1251_tx_id(wl, skb);
 	if (id < 0)
 		return id;

 	fc = *(u16 *)skb->data;
 	tx_hdr = (struct tx_double_buffer_desc *) skb_push(skb,
 							   sizeof(*tx_hdr));

 	tx_hdr->length = cpu_to_le16(skb->len - sizeof(*tx_hdr));
 	rate = ieee80211_get_tx_rate(wl->hw, control);
 	tx_hdr->rate = cpu_to_le16(rate->hw_value);
 	tx_hdr->expiry_time = cpu_to_le32(1 << 16);
 	tx_hdr->id = id;

 	tx_hdr->xmit_queue = wl1251_tx_get_queue(skb_get_queue_mapping(skb));

 	wl1251_tx_control(tx_hdr, control, fc);
 	wl1251_tx_frag_block_num(tx_hdr);

 	return 0;
 }

 /* We copy the packet to the target */
 static int wl1251_tx_send_packet(struct wl1251 *wl, struct sk_buff *skb,
 				 struct ieee80211_tx_info *control)
 {
 	struct tx_double_buffer_desc *tx_hdr;
 	int len;
 	u32 addr;

 	if (!skb)
 		return -EINVAL;

 	tx_hdr = (struct tx_double_buffer_desc *) skb->data;

 	if (control->control.hw_key &&
 	    control->control.hw_key->cipher == WLAN_CIPHER_SUITE_TKIP) {
 		int hdrlen;
 		__le16 fc;
 		u16 length;
 		u8 *pos;

 		fc = *(__le16 *)(skb->data + sizeof(*tx_hdr));
 		length = le16_to_cpu(tx_hdr->length) + WL1251_TKIP_IV_SPACE;
 		tx_hdr->length = cpu_to_le16(length);

 		hdrlen = ieee80211_hdrlen(fc);

 		pos = skb_push(skb, WL1251_TKIP_IV_SPACE);
 		memmove(pos, pos + WL1251_TKIP_IV_SPACE,
 			sizeof(*tx_hdr) + hdrlen);
 	}

 	/* Revisit. This is a workaround for getting non-aligned packets.
 	   This happens at least with EAPOL packets from the user space.
 	   Our DMA requires packets to be aligned on a 4-byte boundary.
 	*/
 	if (unlikely((long)skb->data & 0x03)) {
 		int offset = (4 - (long)skb->data) & 0x03;
 		wl1251_debug(DEBUG_TX, "skb offset %d", offset);

 		/* check whether the current skb can be used */
 		if (skb_cloned(skb) || (skb_tailroom(skb) < offset)) {
 			struct sk_buff *newskb = skb_copy_expand(skb, 0, 3,
 								 GFP_KERNEL);

 			if (unlikely(newskb == NULL)) {
 				wl1251_error("Can't allocate skb!");
 				return -EINVAL;
 			}

 			tx_hdr = (struct tx_double_buffer_desc *) newskb->data;

 			dev_kfree_skb_any(skb);
 			wl->tx_frames[tx_hdr->id] = skb = newskb;

 			offset = (4 - (long)skb->data) & 0x03;
 			wl1251_debug(DEBUG_TX, "new skb offset %d", offset);
 		}

 		/* align the buffer on a 4-byte boundary */
 		if (offset) {
 			unsigned char *src = skb->data;
 			skb_reserve(skb, offset);
 			memmove(skb->data, src, skb->len);
 			tx_hdr = (struct tx_double_buffer_desc *) skb->data;
 		}
 	}

 	/* Our skb->data at this point includes the HW header */
 	len = WL1251_TX_ALIGN(skb->len);

 	if (wl->data_in_count & 0x1)
 		addr = wl->data_path->tx_packet_ring_addr +
 			wl->data_path->tx_packet_ring_chunk_size;
 	else
 		addr = wl->data_path->tx_packet_ring_addr;

 	wl1251_mem_write(wl, addr, skb->data, len);

 	wl1251_debug(DEBUG_TX, "tx id %u skb 0x%p payload %u rate 0x%x "
 		     "queue %d", tx_hdr->id, skb, tx_hdr->length,
 		     tx_hdr->rate, tx_hdr->xmit_queue);

 	return 0;
 }

 static void wl1251_tx_trigger(struct wl1251 *wl)
 {
 	u32 data, addr;

 	if (wl->data_in_count & 0x1) {
 		addr = ACX_REG_INTERRUPT_TRIG_H;
 		data = INTR_TRIG_TX_PROC1;
 	} else {
 		addr = ACX_REG_INTERRUPT_TRIG;
 		data = INTR_TRIG_TX_PROC0;
 	}

 	wl1251_reg_write32(wl, addr, data);

 	/* Bumping data in */
 	wl->data_in_count = (wl->data_in_count + 1) &
 		TX_STATUS_DATA_OUT_COUNT_MASK;
 }

 /* caller must hold wl->mutex */
 static int wl1251_tx_frame(struct wl1251 *wl, struct sk_buff *skb)
 {
 	struct ieee80211_tx_info *info;
 	int ret = 0;
 	u8 idx;

 	info = IEEE80211_SKB_CB(skb);

 	if (info->control.hw_key) {
 		idx = info->control.hw_key->hw_key_idx;
 		if (unlikely(wl->default_key != idx)) {
 			ret = wl1251_acx_default_key(wl, idx);
 			if (ret < 0)
 				return ret;
 		}
 	}

 	ret = wl1251_tx_path_status(wl);
 	if (ret < 0)
 		return ret;

 	ret = wl1251_tx_fill_hdr(wl, skb, info);
 	if (ret < 0)
 		return ret;

 	ret = wl1251_tx_send_packet(wl, skb, info);
 	if (ret < 0)
 		return ret;

 	wl1251_tx_trigger(wl);

 	return ret;
 }

 void wl1251_tx_work(struct work_struct *work)
 {
 	struct wl1251 *wl = container_of(work, struct wl1251, tx_work);
 	struct sk_buff *skb;
 	bool woken_up = false;
 	int ret;

 	mutex_lock(&wl->mutex);

 	if (unlikely(wl->state == WL1251_STATE_OFF))
 		goto out;

 	while ((skb = skb_dequeue(&wl->tx_queue))) {
 		if (!woken_up) {
 			ret = wl1251_ps_elp_wakeup(wl);
 			if (ret < 0)
 				goto out;
 			woken_up = true;
 		}

 		ret = wl1251_tx_frame(wl, skb);
 		if (ret == -EBUSY) {
 			skb_queue_head(&wl->tx_queue, skb);
 			goto out;
 		} else if (ret < 0) {
 			dev_kfree_skb(skb);
 			goto out;
 		}
 	}

 out:
 	if (woken_up)
 		wl1251_ps_elp_sleep(wl);

 	mutex_unlock(&wl->mutex);
 }

 static const char *wl1251_tx_parse_status(u8 status)
 {
 	/* 8 bit status field, one character per bit plus null */
 	static char buf[9];
 	int i = 0;

 	memset(buf, 0, sizeof(buf));

 	if (status & TX_DMA_ERROR)
 		buf[i++] = 'm';
 	if (status & TX_DISABLED)
 		buf[i++] = 'd';
 	if (status & TX_RETRY_EXCEEDED)
 		buf[i++] = 'r';
 	if (status & TX_TIMEOUT)
 		buf[i++] = 't';
 	if (status & TX_KEY_NOT_FOUND)
 		buf[i++] = 'k';
 	if (status & TX_ENCRYPT_FAIL)
 		buf[i++] = 'e';
 	if (status & TX_UNAVAILABLE_PRIORITY)
 		buf[i++] = 'p';

 	/* bit 0 is unused apparently */

 	return buf;
 }

 static void wl1251_tx_packet_cb(struct wl1251 *wl,
 				struct tx_result *result)
 {
 	struct ieee80211_tx_info *info;
 	struct sk_buff *skb;
 	int hdrlen;
 	u8 *frame;

 	skb = wl->tx_frames[result->id];
 	if (skb == NULL) {
 		wl1251_error("SKB for packet %d is NULL", result->id);
 		return;
 	}

 	info = IEEE80211_SKB_CB(skb);

 	if (!(info->flags & IEEE80211_TX_CTL_NO_ACK) &&
 	    (result->status == TX_SUCCESS))
 		info->flags |= IEEE80211_TX_STAT_ACK;

 	info->status.rates[0].count = result->ack_failures + 1;
 	wl->stats.retry_count += result->ack_failures;

 	/*
 	 * We have to remove our private TX header before pushing
 	 * the skb back to mac80211.
 	 */
 	frame = skb_pull(skb, sizeof(struct tx_double_buffer_desc));
 	if (info->control.hw_key &&
 	    info->control.hw_key->cipher == WLAN_CIPHER_SUITE_TKIP) {
 		hdrlen = ieee80211_get_hdrlen_from_skb(skb);
 		memmove(frame + WL1251_TKIP_IV_SPACE, frame, hdrlen);
 		skb_pull(skb, WL1251_TKIP_IV_SPACE);
 	}

 	wl1251_debug(DEBUG_TX, "tx status id %u skb 0x%p failures %u rate 0x%x"
 		     " status 0x%x (%s)",
 		     result->id, skb, result->ack_failures, result->rate,
 		     result->status, wl1251_tx_parse_status(result->status));


 	ieee80211_tx_status(wl->hw, skb);

 	wl->tx_frames[result->id] = NULL;
 }

 /* Called upon reception of a TX complete interrupt */
 void wl1251_tx_complete(struct wl1251 *wl)
 {
 	int i, result_index, num_complete = 0, queue_len;
 	struct tx_result result[FW_TX_CMPLT_BLOCK_SIZE], *result_ptr;
 	unsigned long flags;

 	if (unlikely(wl->state != WL1251_STATE_ON))
 		return;

 	/* First we read the result */
 	wl1251_mem_read(wl, wl->data_path->tx_complete_addr,
 			    result, sizeof(result));

 	result_index = wl->next_tx_complete;

 	for (i = 0; i < ARRAY_SIZE(result); i++) {
 		result_ptr = &result[result_index];

 		if (result_ptr->done_1 == 1 &&
 		    result_ptr->done_2 == 1) {
 			wl1251_tx_packet_cb(wl, result_ptr);

 			result_ptr->done_1 = 0;
 			result_ptr->done_2 = 0;

 			result_index = (result_index + 1) &
 				(FW_TX_CMPLT_BLOCK_SIZE - 1);
 			num_complete++;
 		} else {
 			break;
 		}
 	}

 	queue_len = skb_queue_len(&wl->tx_queue);

 	if ((num_complete > 0) && (queue_len > 0)) {
 		/* firmware buffer has space, reschedule tx_work */
 		wl1251_debug(DEBUG_TX, "tx_complete: reschedule tx_work");
 		ieee80211_queue_work(wl->hw, &wl->tx_work);
 	}

 	if (wl->tx_queue_stopped &&
 	    queue_len <= WL1251_TX_QUEUE_LOW_WATERMARK) {
 		/* tx_queue has space, restart queues */
 		wl1251_debug(DEBUG_TX, "tx_complete: waking queues");
 		spin_lock_irqsave(&wl->wl_lock, flags);
 		ieee80211_wake_queues(wl->hw);
 		wl->tx_queue_stopped = false;
 		spin_unlock_irqrestore(&wl->wl_lock, flags);
 	}

 	/* Every completed frame needs to be acknowledged */
 	if (num_complete) {
 		/*
 		 * If we've wrapped, we have to clear
 		 * the results in 2 steps.
 		 */
 		if (result_index > wl->next_tx_complete) {
 			/* Only 1 write is needed */
 			wl1251_mem_write(wl,
 					 wl->data_path->tx_complete_addr +
 					 (wl->next_tx_complete *
 					  sizeof(struct tx_result)),
 					 &result[wl->next_tx_complete],
 					 num_complete *
 					 sizeof(struct tx_result));


 		} else if (result_index < wl->next_tx_complete) {
 			/* 2 writes are needed */
 			wl1251_mem_write(wl,
 					 wl->data_path->tx_complete_addr +
 					 (wl->next_tx_complete *
 					  sizeof(struct tx_result)),
 					 &result[wl->next_tx_complete],
 					 (FW_TX_CMPLT_BLOCK_SIZE -
 					  wl->next_tx_complete) *
 					 sizeof(struct tx_result));

 			wl1251_mem_write(wl,
 					 wl->data_path->tx_complete_addr,
 					 result,
 					 (num_complete -
 					  FW_TX_CMPLT_BLOCK_SIZE +
 					  wl->next_tx_complete) *
 					 sizeof(struct tx_result));

 		} else {
 			/* We have to write the whole array */
 			wl1251_mem_write(wl,
 					 wl->data_path->tx_complete_addr,
 					 result,
 					 FW_TX_CMPLT_BLOCK_SIZE *
 					 sizeof(struct tx_result));
 		}

 	}

 	wl->next_tx_complete = result_index;
 }

 /* caller must hold wl->mutex */
 void wl1251_tx_flush(struct wl1251 *wl)
 {
 	int i;
 	struct sk_buff *skb;
 	struct ieee80211_tx_info *info;

 	/* TX failure */
 /* 	control->flags = 0; FIXME */

 	while ((skb = skb_dequeue(&wl->tx_queue))) {
 		info = IEEE80211_SKB_CB(skb);

 		wl1251_debug(DEBUG_TX, "flushing skb 0x%p", skb);

 		if (!(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS))
 				continue;

 		ieee80211_tx_status(wl->hw, skb);
 	}

 	for (i = 0; i < FW_TX_CMPLT_BLOCK_SIZE; i++)
 		if (wl->tx_frames[i] != NULL) {
 			skb = wl->tx_frames[i];
 			info = IEEE80211_SKB_CB(skb);

 			if (!(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS))
 				continue;

 			ieee80211_tx_status(wl->hw, skb);
 			wl->tx_frames[i] = NULL;
 		}
 }
	/*
	* This file is part of wl1251
	*
	* Copyright (c) 1998-2007 Texas Instruments Incorporated
	* Copyright (C) 2008 Nokia Corporation
	*
	* 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 "wl1251.h"
	#include "reg.h"
	#include "tx.h"
	#include "ps.h"
	#include "io.h"

	static bool wl1251_tx_double_buffer_busy(struct wl1251 *wl, u32 data_out_count)
	{
	int used, data_in_count;

	data_in_count = wl->data_in_count;

	if (data_in_count < data_out_count)
	/* data_in_count has wrapped */
	data_in_count += TX_STATUS_DATA_OUT_COUNT_MASK + 1;

	used = data_in_count - data_out_count;

	WARN_ON(used < 0);
	WARN_ON(used > DP_TX_PACKET_RING_CHUNK_NUM);

	if (used >= DP_TX_PACKET_RING_CHUNK_NUM)
	return true;
	else
	return false;
	}

	static int wl1251_tx_path_status(struct wl1251 *wl)
	{
	u32 status, addr, data_out_count;
	bool busy;

	addr = wl->data_path->tx_control_addr;
	status = wl1251_mem_read32(wl, addr);
	data_out_count = status & TX_STATUS_DATA_OUT_COUNT_MASK;
	busy = wl1251_tx_double_buffer_busy(wl, data_out_count);

	if (busy)
	return -EBUSY;

	return 0;
	}

	static int wl1251_tx_id(struct wl1251 wl, struct sk_buff skb)
	{
	int i;

	for (i = 0; i < FW_TX_CMPLT_BLOCK_SIZE; i++)
	if (wl->tx_frames[i] == NULL) {
	wl->tx_frames[i] = skb;
	return i;
	}

	return -EBUSY;
	}

	static void wl1251_tx_control(struct tx_double_buffer_desc *tx_hdr,
	struct ieee80211_tx_info *control, u16 fc)
	{
	(u16 )&tx_hdr->control = 0;

	tx_hdr->control.rate_policy = 0;

	/* 802.11 packets */
	tx_hdr->control.packet_type = 0;

	if (control->flags & IEEE80211_TX_CTL_NO_ACK)
	tx_hdr->control.ack_policy = 1;

	tx_hdr->control.tx_complete = 1;

	if ((fc & IEEE80211_FTYPE_DATA) &&
	((fc & IEEE80211_STYPE_QOS_DATA) \|\|
	(fc & IEEE80211_STYPE_QOS_NULLFUNC)))
	tx_hdr->control.qos = 1;
	}

	/* RSN + MIC = 8 + 8 = 16 bytes (worst case - AES). */
	#define MAX_MSDU_SECURITY_LENGTH 16
	#define MAX_MPDU_SECURITY_LENGTH 16
	#define WLAN_QOS_HDR_LEN 26
	#define MAX_MPDU_HEADER_AND_SECURITY (MAX_MPDU_SECURITY_LENGTH + \
	WLAN_QOS_HDR_LEN)
	#define HW_BLOCK_SIZE 252
	static void wl1251_tx_frag_block_num(struct tx_double_buffer_desc *tx_hdr)
	{
	u16 payload_len, frag_threshold, mem_blocks;
	u16 num_mpdus, mem_blocks_per_frag;

	frag_threshold = IEEE80211_MAX_FRAG_THRESHOLD;
	tx_hdr->frag_threshold = cpu_to_le16(frag_threshold);

	payload_len = le16_to_cpu(tx_hdr->length) + MAX_MSDU_SECURITY_LENGTH;

	if (payload_len > frag_threshold) {
	mem_blocks_per_frag =
	((frag_threshold + MAX_MPDU_HEADER_AND_SECURITY) /
	HW_BLOCK_SIZE) + 1;
	num_mpdus = payload_len / frag_threshold;
	mem_blocks = num_mpdus * mem_blocks_per_frag;
	payload_len -= num_mpdus * frag_threshold;
	num_mpdus++;

	} else {
	mem_blocks_per_frag = 0;
	mem_blocks = 0;
	num_mpdus = 1;
	}

	mem_blocks += (payload_len / HW_BLOCK_SIZE) + 1;

	if (num_mpdus > 1)
	mem_blocks += min(num_mpdus, mem_blocks_per_frag);

	tx_hdr->num_mem_blocks = mem_blocks;
	}

	static int wl1251_tx_fill_hdr(struct wl1251 wl, struct sk_buff skb,
	struct ieee80211_tx_info *control)
	{
	struct tx_double_buffer_desc *tx_hdr;
	struct ieee80211_rate *rate;
	int id;
	u16 fc;

	if (!skb)
	return -EINVAL;

	id = wl1251_tx_id(wl, skb);
	if (id < 0)
	return id;

	fc = (u16 )skb->data;
	tx_hdr = (struct tx_double_buffer_desc *) skb_push(skb,
	sizeof(*tx_hdr));

	tx_hdr->length = cpu_to_le16(skb->len - sizeof(*tx_hdr));
	rate = ieee80211_get_tx_rate(wl->hw, control);
	tx_hdr->rate = cpu_to_le16(rate->hw_value);
	tx_hdr->expiry_time = cpu_to_le32(1 << 16);
	tx_hdr->id = id;

	tx_hdr->xmit_queue = wl1251_tx_get_queue(skb_get_queue_mapping(skb));

	wl1251_tx_control(tx_hdr, control, fc);
	wl1251_tx_frag_block_num(tx_hdr);

	return 0;
	}

	/* We copy the packet to the target */
	static int wl1251_tx_send_packet(struct wl1251 wl, struct sk_buff skb,
	struct ieee80211_tx_info *control)
	{
	struct tx_double_buffer_desc *tx_hdr;
	int len;
	u32 addr;

	if (!skb)
	return -EINVAL;

	tx_hdr = (struct tx_double_buffer_desc *) skb->data;

	if (control->control.hw_key &&
	control->control.hw_key->cipher == WLAN_CIPHER_SUITE_TKIP) {
	int hdrlen;
	__le16 fc;
	u16 length;
	u8 *pos;

	fc = (__le16 )(skb->data + sizeof(*tx_hdr));
	length = le16_to_cpu(tx_hdr->length) + WL1251_TKIP_IV_SPACE;
	tx_hdr->length = cpu_to_le16(length);

	hdrlen = ieee80211_hdrlen(fc);

	pos = skb_push(skb, WL1251_TKIP_IV_SPACE);
	memmove(pos, pos + WL1251_TKIP_IV_SPACE,
	sizeof(*tx_hdr) + hdrlen);
	}

	/* Revisit. This is a workaround for getting non-aligned packets.
	This happens at least with EAPOL packets from the user space.
	Our DMA requires packets to be aligned on a 4-byte boundary.
	*/
	if (unlikely((long)skb->data & 0x03)) {
	int offset = (4 - (long)skb->data) & 0x03;
	wl1251_debug(DEBUG_TX, "skb offset %d", offset);

	/* check whether the current skb can be used */
	if (skb_cloned(skb) \|\| (skb_tailroom(skb) < offset)) {
	struct sk_buff *newskb = skb_copy_expand(skb, 0, 3,
	GFP_KERNEL);

	if (unlikely(newskb == NULL)) {
	wl1251_error("Can't allocate skb!");
	return -EINVAL;
	}

	tx_hdr = (struct tx_double_buffer_desc *) newskb->data;

	dev_kfree_skb_any(skb);
	wl->tx_frames[tx_hdr->id] = skb = newskb;

	offset = (4 - (long)skb->data) & 0x03;
	wl1251_debug(DEBUG_TX, "new skb offset %d", offset);
	}

	/* align the buffer on a 4-byte boundary */
	if (offset) {
	unsigned char *src = skb->data;
	skb_reserve(skb, offset);
	memmove(skb->data, src, skb->len);
	tx_hdr = (struct tx_double_buffer_desc *) skb->data;
	}
	}

	/* Our skb->data at this point includes the HW header */
	len = WL1251_TX_ALIGN(skb->len);

	if (wl->data_in_count & 0x1)
	addr = wl->data_path->tx_packet_ring_addr +
	wl->data_path->tx_packet_ring_chunk_size;
	else
	addr = wl->data_path->tx_packet_ring_addr;

	wl1251_mem_write(wl, addr, skb->data, len);

	wl1251_debug(DEBUG_TX, "tx id %u skb 0x%p payload %u rate 0x%x "
	"queue %d", tx_hdr->id, skb, tx_hdr->length,
	tx_hdr->rate, tx_hdr->xmit_queue);

	return 0;
	}

	static void wl1251_tx_trigger(struct wl1251 *wl)
	{
	u32 data, addr;

	if (wl->data_in_count & 0x1) {
	addr = ACX_REG_INTERRUPT_TRIG_H;
	data = INTR_TRIG_TX_PROC1;
	} else {
	addr = ACX_REG_INTERRUPT_TRIG;
	data = INTR_TRIG_TX_PROC0;
	}

	wl1251_reg_write32(wl, addr, data);

	/* Bumping data in */
	wl->data_in_count = (wl->data_in_count + 1) &
	TX_STATUS_DATA_OUT_COUNT_MASK;
	}

	/* caller must hold wl->mutex */
	static int wl1251_tx_frame(struct wl1251 wl, struct sk_buff skb)
	{
	struct ieee80211_tx_info *info;
	int ret = 0;
	u8 idx;

	info = IEEE80211_SKB_CB(skb);

	if (info->control.hw_key) {
	idx = info->control.hw_key->hw_key_idx;
	if (unlikely(wl->default_key != idx)) {
	ret = wl1251_acx_default_key(wl, idx);
	if (ret < 0)
	return ret;
	}
	}

	ret = wl1251_tx_path_status(wl);
	if (ret < 0)
	return ret;

	ret = wl1251_tx_fill_hdr(wl, skb, info);
	if (ret < 0)
	return ret;

	ret = wl1251_tx_send_packet(wl, skb, info);
	if (ret < 0)
	return ret;

	wl1251_tx_trigger(wl);

	return ret;
	}

	void wl1251_tx_work(struct work_struct *work)
	{
	struct wl1251 *wl = container_of(work, struct wl1251, tx_work);
	struct sk_buff *skb;
	bool woken_up = false;
	int ret;

	mutex_lock(&wl->mutex);

	if (unlikely(wl->state == WL1251_STATE_OFF))
	goto out;

	while ((skb = skb_dequeue(&wl->tx_queue))) {
	if (!woken_up) {
	ret = wl1251_ps_elp_wakeup(wl);
	if (ret < 0)
	goto out;
	woken_up = true;
	}

	ret = wl1251_tx_frame(wl, skb);
	if (ret == -EBUSY) {
	skb_queue_head(&wl->tx_queue, skb);
	goto out;
	} else if (ret < 0) {
	dev_kfree_skb(skb);
	goto out;
	}
	}

	out:
	if (woken_up)
	wl1251_ps_elp_sleep(wl);

	mutex_unlock(&wl->mutex);
	}

	static const char *wl1251_tx_parse_status(u8 status)
	{
	/* 8 bit status field, one character per bit plus null */
	static char buf[9];
	int i = 0;

	memset(buf, 0, sizeof(buf));

	if (status & TX_DMA_ERROR)
	buf[i++] = 'm';
	if (status & TX_DISABLED)
	buf[i++] = 'd';
	if (status & TX_RETRY_EXCEEDED)
	buf[i++] = 'r';
	if (status & TX_TIMEOUT)
	buf[i++] = 't';
	if (status & TX_KEY_NOT_FOUND)
	buf[i++] = 'k';
	if (status & TX_ENCRYPT_FAIL)
	buf[i++] = 'e';
	if (status & TX_UNAVAILABLE_PRIORITY)
	buf[i++] = 'p';

	/* bit 0 is unused apparently */

	return buf;
	}

	static void wl1251_tx_packet_cb(struct wl1251 *wl,
	struct tx_result *result)
	{
	struct ieee80211_tx_info *info;
	struct sk_buff *skb;
	int hdrlen;
	u8 *frame;

	skb = wl->tx_frames[result->id];
	if (skb == NULL) {
	wl1251_error("SKB for packet %d is NULL", result->id);
	return;
	}

	info = IEEE80211_SKB_CB(skb);

	if (!(info->flags & IEEE80211_TX_CTL_NO_ACK) &&
	(result->status == TX_SUCCESS))
	info->flags \|= IEEE80211_TX_STAT_ACK;

	info->status.rates[0].count = result->ack_failures + 1;
	wl->stats.retry_count += result->ack_failures;

	/*
	* We have to remove our private TX header before pushing
	* the skb back to mac80211.
	*/
	frame = skb_pull(skb, sizeof(struct tx_double_buffer_desc));
	if (info->control.hw_key &&
	info->control.hw_key->cipher == WLAN_CIPHER_SUITE_TKIP) {
	hdrlen = ieee80211_get_hdrlen_from_skb(skb);
	memmove(frame + WL1251_TKIP_IV_SPACE, frame, hdrlen);
	skb_pull(skb, WL1251_TKIP_IV_SPACE);
	}

	wl1251_debug(DEBUG_TX, "tx status id %u skb 0x%p failures %u rate 0x%x"
	" status 0x%x (%s)",
	result->id, skb, result->ack_failures, result->rate,
	result->status, wl1251_tx_parse_status(result->status));


	ieee80211_tx_status(wl->hw, skb);

	wl->tx_frames[result->id] = NULL;
	}

	/* Called upon reception of a TX complete interrupt */
	void wl1251_tx_complete(struct wl1251 *wl)
	{
	int i, result_index, num_complete = 0, queue_len;
	struct tx_result result[FW_TX_CMPLT_BLOCK_SIZE], *result_ptr;
	unsigned long flags;

	if (unlikely(wl->state != WL1251_STATE_ON))
	return;

	/* First we read the result */
	wl1251_mem_read(wl, wl->data_path->tx_complete_addr,
	result, sizeof(result));

	result_index = wl->next_tx_complete;

	for (i = 0; i < ARRAY_SIZE(result); i++) {
	result_ptr = &result[result_index];

	if (result_ptr->done_1 == 1 &&
	result_ptr->done_2 == 1) {
	wl1251_tx_packet_cb(wl, result_ptr);

	result_ptr->done_1 = 0;
	result_ptr->done_2 = 0;

	result_index = (result_index + 1) &
	(FW_TX_CMPLT_BLOCK_SIZE - 1);
	num_complete++;
	} else {
	break;
	}
	}

	queue_len = skb_queue_len(&wl->tx_queue);

	if ((num_complete > 0) && (queue_len > 0)) {
	/* firmware buffer has space, reschedule tx_work */
	wl1251_debug(DEBUG_TX, "tx_complete: reschedule tx_work");
	ieee80211_queue_work(wl->hw, &wl->tx_work);
	}

	if (wl->tx_queue_stopped &&
	queue_len <= WL1251_TX_QUEUE_LOW_WATERMARK) {
	/* tx_queue has space, restart queues */
	wl1251_debug(DEBUG_TX, "tx_complete: waking queues");
	spin_lock_irqsave(&wl->wl_lock, flags);
	ieee80211_wake_queues(wl->hw);
	wl->tx_queue_stopped = false;
	spin_unlock_irqrestore(&wl->wl_lock, flags);
	}

	/* Every completed frame needs to be acknowledged */
	if (num_complete) {
	/*
	* If we've wrapped, we have to clear
	* the results in 2 steps.
	*/
	if (result_index > wl->next_tx_complete) {
	/* Only 1 write is needed */
	wl1251_mem_write(wl,
	wl->data_path->tx_complete_addr +
	(wl->next_tx_complete *
	sizeof(struct tx_result)),
	&result[wl->next_tx_complete],
	num_complete *
	sizeof(struct tx_result));


	} else if (result_index < wl->next_tx_complete) {
	/* 2 writes are needed */
	wl1251_mem_write(wl,
	wl->data_path->tx_complete_addr +
	(wl->next_tx_complete *
	sizeof(struct tx_result)),
	&result[wl->next_tx_complete],
	(FW_TX_CMPLT_BLOCK_SIZE -
	wl->next_tx_complete) *
	sizeof(struct tx_result));

	wl1251_mem_write(wl,
	wl->data_path->tx_complete_addr,
	result,
	(num_complete -
	FW_TX_CMPLT_BLOCK_SIZE +
	wl->next_tx_complete) *
	sizeof(struct tx_result));

	} else {
	/* We have to write the whole array */
	wl1251_mem_write(wl,
	wl->data_path->tx_complete_addr,
	result,
	FW_TX_CMPLT_BLOCK_SIZE *
	sizeof(struct tx_result));
	}

	}

	wl->next_tx_complete = result_index;
	}

	/* caller must hold wl->mutex */
	void wl1251_tx_flush(struct wl1251 *wl)
	{
	int i;
	struct sk_buff *skb;
	struct ieee80211_tx_info *info;

	/* TX failure */
	/* control->flags = 0; FIXME */

	while ((skb = skb_dequeue(&wl->tx_queue))) {
	info = IEEE80211_SKB_CB(skb);

	wl1251_debug(DEBUG_TX, "flushing skb 0x%p", skb);

	if (!(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS))
	continue;

	ieee80211_tx_status(wl->hw, skb);
	}

	for (i = 0; i < FW_TX_CMPLT_BLOCK_SIZE; i++)
	if (wl->tx_frames[i] != NULL) {
	skb = wl->tx_frames[i];
	info = IEEE80211_SKB_CB(skb);

	if (!(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS))
	continue;

	ieee80211_tx_status(wl->hw, skb);
	wl->tx_frames[i] = NULL;
	}
	}