path: root/drivers/net/wireless/iwlwifi/iwl-agn-lib.c

/******************************************************************************
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2008 - 2010 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License 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 Street, Fifth Floor, Boston, MA 02110,
 * USA
 *
 * The full GNU General Public License is included in this distribution
 * in the file called LICENSE.GPL.
 *
 * Contact Information:
 *  Intel Linux Wireless <ilw@linux.intel.com>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 *****************************************************************************/
#include <linux/etherdevice.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>

#include "iwl-dev.h"
#include "iwl-core.h"
#include "iwl-io.h"
#include "iwl-helpers.h"
#include "iwl-agn-hw.h"
#include "iwl-agn.h"

static inline u32 iwlagn_get_scd_ssn(struct iwl5000_tx_resp *tx_resp)
{
	return le32_to_cpup((__le32 *)&tx_resp->status +
			    tx_resp->frame_count) & MAX_SN;
}

static int iwlagn_tx_status_reply_tx(struct iwl_priv *priv,
				      struct iwl_ht_agg *agg,
				      struct iwl5000_tx_resp *tx_resp,
				      int txq_id, u16 start_idx)
{
	u16 status;
	struct agg_tx_status *frame_status = &tx_resp->status;
	struct ieee80211_tx_info *info = NULL;
	struct ieee80211_hdr *hdr = NULL;
	u32 rate_n_flags = le32_to_cpu(tx_resp->rate_n_flags);
	int i, sh, idx;
	u16 seq;

	if (agg->wait_for_ba)
		IWL_DEBUG_TX_REPLY(priv, "got tx response w/o block-ack\n");

	agg->frame_count = tx_resp->frame_count;
	agg->start_idx = start_idx;
	agg->rate_n_flags = rate_n_flags;
	agg->bitmap = 0;

	/* # frames attempted by Tx command */
	if (agg->frame_count == 1) {
		/* Only one frame was attempted; no block-ack will arrive */
		status = le16_to_cpu(frame_status[0].status);
		idx = start_idx;

		/* FIXME: code repetition */
		IWL_DEBUG_TX_REPLY(priv, "FrameCnt = %d, StartIdx=%d idx=%d\n",
				   agg->frame_count, agg->start_idx, idx);

		info = IEEE80211_SKB_CB(priv->txq[txq_id].txb[idx].skb[0]);
		info->status.rates[0].count = tx_resp->failure_frame + 1;
		info->flags &= ~IEEE80211_TX_CTL_AMPDU;
		info->flags |= iwl_tx_status_to_mac80211(status);
		iwlagn_hwrate_to_tx_control(priv, rate_n_flags, info);

		/* FIXME: code repetition end */

		IWL_DEBUG_TX_REPLY(priv, "1 Frame 0x%x failure :%d\n",
				    status & 0xff, tx_resp->failure_frame);
		IWL_DEBUG_TX_REPLY(priv, "Rate Info rate_n_flags=%x\n", rate_n_flags);

		agg->wait_for_ba = 0;
	} else {
		/* Two or more frames were attempted; expect block-ack */
		u64 bitmap = 0;
		int start = agg->start_idx;

		/* Construct bit-map of pending frames within Tx window */
		for (i = 0; i < agg->frame_count; i++) {
			u16 sc;
			status = le16_to_cpu(frame_status[i].status);
			seq  = le16_to_cpu(frame_status[i].sequence);
			idx = SEQ_TO_INDEX(seq);
			txq_id = SEQ_TO_QUEUE(seq);

			if (status & (AGG_TX_STATE_FEW_BYTES_MSK |
				      AGG_TX_STATE_ABORT_MSK))
				continue;

			IWL_DEBUG_TX_REPLY(priv, "FrameCnt = %d, txq_id=%d idx=%d\n",
					   agg->frame_count, txq_id, idx);

			hdr = iwl_tx_queue_get_hdr(priv, txq_id, idx);
			if (!hdr) {
				IWL_ERR(priv,
					"BUG_ON idx doesn't point to valid skb"
					" idx=%d, txq_id=%d\n", idx, txq_id);
				return -1;
			}

			sc = le16_to_cpu(hdr->seq_ctrl);
			if (idx != (SEQ_TO_SN(sc) & 0xff)) {
				IWL_ERR(priv,
					"BUG_ON idx doesn't match seq control"
					" idx=%d, seq_idx=%d, seq=%d\n",
					  idx, SEQ_TO_SN(sc),
					  hdr->seq_ctrl);
				return -1;
			}

			IWL_DEBUG_TX_REPLY(priv, "AGG Frame i=%d idx %d seq=%d\n",
					   i, idx, SEQ_TO_SN(sc));

			sh = idx - start;
			if (sh > 64) {
				sh = (start - idx) + 0xff;
				bitmap = bitmap << sh;
				sh = 0;
				start = idx;
			} else if (sh < -64)
				sh  = 0xff - (start - idx);
			else if (sh < 0) {
				sh = start - idx;
				start = idx;
				bitmap = bitmap << sh;
				sh = 0;
			}
			bitmap |= 1ULL << sh;
			IWL_DEBUG_TX_REPLY(priv, "start=%d bitmap=0x%llx\n",
					   start, (unsigned long long)bitmap);
		}

		agg->bitmap = bitmap;
		agg->start_idx = start;
		IWL_DEBUG_TX_REPLY(priv, "Frames %d start_idx=%d bitmap=0x%llx\n",
				   agg->frame_count, agg->start_idx,
				   (unsigned long long)agg->bitmap);

		if (bitmap)
			agg->wait_for_ba = 1;
	}
	return 0;
}

void iwl_check_abort_status(struct iwl_priv *priv,
			    u8 frame_count, u32 status)
{
	if (frame_count == 1 && status == TX_STATUS_FAIL_RFKILL_FLUSH) {
		IWL_ERR(priv, "TODO: Implement Tx flush command!!!\n");
	}
}

static void iwlagn_rx_reply_tx(struct iwl_priv *priv,
				struct iwl_rx_mem_buffer *rxb)
{
	struct iwl_rx_packet *pkt = rxb_addr(rxb);
	u16 sequence = le16_to_cpu(pkt->hdr.sequence);
	int txq_id = SEQ_TO_QUEUE(sequence);
	int index = SEQ_TO_INDEX(sequence);
	struct iwl_tx_queue *txq = &priv->txq[txq_id];
	struct ieee80211_tx_info *info;
	struct iwl5000_tx_resp *tx_resp = (void *)&pkt->u.raw[0];
	u32  status = le16_to_cpu(tx_resp->status.status);
	int tid;
	int sta_id;
	int freed;

	if ((index >= txq->q.n_bd) || (iwl_queue_used(&txq->q, index) == 0)) {
		IWL_ERR(priv, "Read index for DMA queue txq_id (%d) index %d "
			  "is out of range [0-%d] %d %d\n", txq_id,
			  index, txq->q.n_bd, txq->q.write_ptr,
			  txq->q.read_ptr);
		return;
	}

	info = IEEE80211_SKB_CB(txq->txb[txq->q.read_ptr].skb[0]);
	memset(&info->status, 0, sizeof(info->status));

	tid = (tx_resp->ra_tid & IWL50_TX_RES_TID_MSK) >> IWL50_TX_RES_TID_POS;
	sta_id = (tx_resp->ra_tid & IWL50_TX_RES_RA_MSK) >> IWL50_TX_RES_RA_POS;

	if (txq->sched_retry) {
		const u32 scd_ssn = iwlagn_get_scd_ssn(tx_resp);
		struct iwl_ht_agg *agg = NULL;

		agg = &priv->stations[sta_id].tid[tid].agg;

		iwlagn_tx_status_reply_tx(priv, agg, tx_resp, txq_id, index);

		/* check if BAR is needed */
		if ((tx_resp->frame_count == 1) && !iwl_is_tx_success(status))
			info->flags |= IEEE80211_TX_STAT_AMPDU_NO_BACK;

		if (txq->q.read_ptr != (scd_ssn & 0xff)) {
			index = iwl_queue_dec_wrap(scd_ssn & 0xff, txq->q.n_bd);
			IWL_DEBUG_TX_REPLY(priv, "Retry scheduler reclaim "
					"scd_ssn=%d idx=%d txq=%d swq=%d\n",
					scd_ssn , index, txq_id, txq->swq_id);

			freed = iwlagn_tx_queue_reclaim(priv, txq_id, index);
			iwl_free_tfds_in_queue(priv, sta_id, tid, freed);

			if (priv->mac80211_registered &&
			    (iwl_queue_space(&txq->q) > txq->q.low_mark) &&
			    (agg->state != IWL_EMPTYING_HW_QUEUE_DELBA)) {
				if (agg->state == IWL_AGG_OFF)
					iwl_wake_queue(priv, txq_id);
				else
					iwl_wake_queue(priv, txq->swq_id);
			}
		}
	} else {
		BUG_ON(txq_id != txq->swq_id);

		info->status.rates[0].count = tx_resp->failure_frame + 1;
		info->flags |= iwl_tx_status_to_mac80211(status);
		iwlagn_hwrate_to_tx_control(priv,
					le32_to_cpu(tx_resp->rate_n_flags),
					info);

		IWL_DEBUG_TX_REPLY(priv, "TXQ %d status %s (0x%08x) rate_n_flags "
				   "0x%x retries %d\n",
				   txq_id,
				   iwl_get_tx_fail_reason(status), status,
				   le32_to_cpu(tx_resp->rate_n_flags),
				   tx_resp->failure_frame);

		freed = iwlagn_tx_queue_reclaim(priv, txq_id, index);
		iwl_free_tfds_in_queue(priv, sta_id, tid, freed);

		if (priv->mac80211_registered &&
		    (iwl_queue_space(&txq->q) > txq->q.low_mark))
			iwl_wake_queue(priv, txq_id);
	}

	iwlagn_txq_check_empty(priv, sta_id, tid, txq_id);

	iwl_check_abort_status(priv, tx_resp->frame_count, status);
}

void iwlagn_rx_handler_setup(struct iwl_priv *priv)
{
	/* init calibration handlers */
	priv->rx_handlers[CALIBRATION_RES_NOTIFICATION] =
					iwlagn_rx_calib_result;
	priv->rx_handlers[CALIBRATION_COMPLETE_NOTIFICATION] =
					iwlagn_rx_calib_complete;
	priv->rx_handlers[REPLY_TX] = iwlagn_rx_reply_tx;
}

void iwlagn_setup_deferred_work(struct iwl_priv *priv)
{
	/* in agn, the tx power calibration is done in uCode */
	priv->disable_tx_power_cal = 1;
}

int iwlagn_hw_valid_rtc_data_addr(u32 addr)
{
	return (addr >= IWLAGN_RTC_DATA_LOWER_BOUND) &&
		(addr < IWLAGN_RTC_DATA_UPPER_BOUND);
}

int iwlagn_send_tx_power(struct iwl_priv *priv)
{
	struct iwl5000_tx_power_dbm_cmd tx_power_cmd;
	u8 tx_ant_cfg_cmd;

	/* half dBm need to multiply */
	tx_power_cmd.global_lmt = (s8)(2 * priv->tx_power_user_lmt);

	if (priv->tx_power_lmt_in_half_dbm &&
	    priv->tx_power_lmt_in_half_dbm < tx_power_cmd.global_lmt) {
		/*
		 * For the newer devices which using enhanced/extend tx power
		 * table in EEPROM, the format is in half dBm. driver need to
		 * convert to dBm format before report to mac80211.
		 * By doing so, there is a possibility of 1/2 dBm resolution
		 * lost. driver will perform "round-up" operation before
		 * reporting, but it will cause 1/2 dBm tx power over the
		 * regulatory limit. Perform the checking here, if the
		 * "tx_power_user_lmt" is higher than EEPROM value (in
		 * half-dBm format), lower the tx power based on EEPROM
		 */
		tx_power_cmd.global_lmt = priv->tx_power_lmt_in_half_dbm;
	}
	tx_power_cmd.flags = IWL50_TX_POWER_NO_CLOSED;
	tx_power_cmd.srv_chan_lmt = IWL50_TX_POWER_AUTO;

	if (IWL_UCODE_API(priv->ucode_ver) == 1)
		tx_ant_cfg_cmd = REPLY_TX_POWER_DBM_CMD_V1;
	else
		tx_ant_cfg_cmd = REPLY_TX_POWER_DBM_CMD;

	return  iwl_send_cmd_pdu_async(priv, tx_ant_cfg_cmd,
				       sizeof(tx_power_cmd), &tx_power_cmd,
				       NULL);
}

void iwlagn_temperature(struct iwl_priv *priv)
{
	/* store temperature from statistics (in Celsius) */
	priv->temperature = le32_to_cpu(priv->statistics.general.temperature);
	iwl_tt_handler(priv);
}

u16 iwlagn_eeprom_calib_version(struct iwl_priv *priv)
{
	struct iwl_eeprom_calib_hdr {
		u8 version;
		u8 pa_type;
		u16 voltage;
	} *hdr;

	hdr = (struct iwl_eeprom_calib_hdr *)iwl_eeprom_query_addr(priv,
							EEPROM_CALIB_ALL);
	return hdr->version;

}

/*
 * EEPROM
 */
static u32 eeprom_indirect_address(const struct iwl_priv *priv, u32 address)
{
	u16 offset = 0;

	if ((address & INDIRECT_ADDRESS) == 0)
		return address;

	switch (address & INDIRECT_TYPE_MSK) {
	case INDIRECT_HOST:
		offset = iwl_eeprom_query16(priv, EEPROM_LINK_HOST);
		break;
	case INDIRECT_GENERAL:
		offset = iwl_eeprom_query16(priv, EEPROM_LINK_GENERAL);
		break;
	case INDIRECT_REGULATORY:
		offset = iwl_eeprom_query16(priv, EEPROM_LINK_REGULATORY);
		break;
	case INDIRECT_CALIBRATION:
		offset = iwl_eeprom_query16(priv, EEPROM_LINK_CALIBRATION);
		break;
	case INDIRECT_PROCESS_ADJST:
		offset = iwl_eeprom_query16(priv, EEPROM_LINK_PROCESS_ADJST);
		break;
	case INDIRECT_OTHERS:
		offset = iwl_eeprom_query16(priv, EEPROM_LINK_OTHERS);
		break;
	default:
		IWL_ERR(priv, "illegal indirect type: 0x%X\n",
		address & INDIRECT_TYPE_MSK);
		break;
	}

	/* translate the offset from words to byte */
	return (address & ADDRESS_MSK) + (offset << 1);
}

const u8 *iwlagn_eeprom_query_addr(const struct iwl_priv *priv,
					   size_t offset)
{
	u32 address = eeprom_indirect_address(priv, offset);
	BUG_ON(address >= priv->cfg->eeprom_size);
	return &priv->eeprom[address];
}

struct iwl_mod_params iwlagn_mod_params = {
	.amsdu_size_8K = 1,
	.restart_fw = 1,
	/* the rest are 0 by default */
};

void iwlagn_rx_queue_reset(struct iwl_priv *priv, struct iwl_rx_queue *rxq)
{
	unsigned long flags;
	int i;
	spin_lock_irqsave(&rxq->lock, flags);
	INIT_LIST_HEAD(&rxq->rx_free);
	INIT_LIST_HEAD(&rxq->rx_used);
	/* Fill the rx_used queue with _all_ of the Rx buffers */
	for (i = 0; i < RX_FREE_BUFFERS + RX_QUEUE_SIZE; i++) {
		/* In the reset function, these buffers may have been allocated
		 * to an SKB, so we need to unmap and free potential storage */
		if (rxq->pool[i].page != NULL) {
			pci_unmap_page(priv->pci_dev, rxq->pool[i].page_dma,
				PAGE_SIZE << priv->hw_params.rx_page_order,
				PCI_DMA_FROMDEVICE);
			__iwl_free_pages(priv, rxq->pool[i].page);
			rxq->pool[i].page = NULL;
		}
		list_add_tail(&rxq->pool[i].list, &rxq->rx_used);
	}

	for (i = 0; i < RX_QUEUE_SIZE; i++)
		rxq->queue[i] = NULL;

	/* Set us so that we have processed and used all buffers, but have
	 * not restocked the Rx queue with fresh buffers */
	rxq->read = rxq->write = 0;
	rxq->write_actual = 0;
	rxq->free_count = 0;
	spin_unlock_irqrestore(&rxq->lock, flags);
}

int iwlagn_rx_init(struct iwl_priv *priv, struct iwl_rx_queue *rxq)
{
	u32 rb_size;
	const u32 rfdnlog = RX_QUEUE_SIZE_LOG; /* 256 RBDs */
	u32 rb_timeout = 0; /* FIXME: RX_RB_TIMEOUT for all devices? */

	if (!priv->cfg->use_isr_legacy)
		rb_timeout = RX_RB_TIMEOUT;

	if (priv->cfg->mod_params->amsdu_size_8K)
		rb_size = FH_RCSR_RX_CONFIG_REG_VAL_RB_SIZE_8K;
	else
		rb_size = FH_RCSR_RX_CONFIG_REG_VAL_RB_SIZE_4K;

	/* Stop Rx DMA */
	iwl_write_direct32(priv, FH_MEM_RCSR_CHNL0_CONFIG_REG, 0);

	/* Reset driver's Rx queue write index */
	iwl_write_direct32(priv, FH_RSCSR_CHNL0_RBDCB_WPTR_REG, 0);

	/* Tell device where to find RBD circular buffer in DRAM */
	iwl_write_direct32(priv, FH_RSCSR_CHNL0_RBDCB_BASE_REG,
			   (u32)(rxq->dma_addr >> 8));

	/* Tell device where in DRAM to update its Rx status */
	iwl_write_direct32(priv, FH_RSCSR_CHNL0_STTS_WPTR_REG,
			   rxq->rb_stts_dma >> 4);

	/* Enable Rx DMA
	 * FH_RCSR_CHNL0_RX_IGNORE_RXF_EMPTY is set because of HW bug in
	 *      the credit mechanism in 5000 HW RX FIFO
	 * Direct rx interrupts to hosts
	 * Rx buffer size 4 or 8k
	 * RB timeout 0x10
	 * 256 RBDs
	 */
	iwl_write_direct32(priv, FH_MEM_RCSR_CHNL0_CONFIG_REG,
			   FH_RCSR_RX_CONFIG_CHNL_EN_ENABLE_VAL |
			   FH_RCSR_CHNL0_RX_IGNORE_RXF_EMPTY |
			   FH_RCSR_CHNL0_RX_CONFIG_IRQ_DEST_INT_HOST_VAL |
			   FH_RCSR_CHNL0_RX_CONFIG_SINGLE_FRAME_MSK |
			   rb_size|
			   (rb_timeout << FH_RCSR_RX_CONFIG_REG_IRQ_RBTH_POS)|
			   (rfdnlog << FH_RCSR_RX_CONFIG_RBDCB_SIZE_POS));

	/* Set interrupt coalescing timer to default (2048 usecs) */
	iwl_write8(priv, CSR_INT_COALESCING, IWL_HOST_INT_TIMEOUT_DEF);

	return 0;
}

int iwlagn_hw_nic_init(struct iwl_priv *priv)
{
	unsigned long flags;
	struct iwl_rx_queue *rxq = &priv->rxq;
	int ret;

	/* nic_init */
	spin_lock_irqsave(&priv->lock, flags);
	priv->cfg->ops->lib->apm_ops.init(priv);

	/* Set interrupt coalescing calibration timer to default (512 usecs) */
	iwl_write8(priv, CSR_INT_COALESCING, IWL_HOST_INT_CALIB_TIMEOUT_DEF);

	spin_unlock_irqrestore(&priv->lock, flags);

	ret = priv->cfg->ops->lib->apm_ops.set_pwr_src(priv, IWL_PWR_SRC_VMAIN);

	priv->cfg->ops->lib->apm_ops.config(priv);

	/* Allocate the RX queue, or reset if it is already allocated */
	if (!rxq->bd) {
		ret = iwl_rx_queue_alloc(priv);
		if (ret) {
			IWL_ERR(priv, "Unable to initialize Rx queue\n");
			return -ENOMEM;
		}
	} else
		iwlagn_rx_queue_reset(priv, rxq);

	iwlagn_rx_replenish(priv);

	iwlagn_rx_init(priv, rxq);

	spin_lock_irqsave(&priv->lock, flags);

	rxq->need_update = 1;
	iwl_rx_queue_update_write_ptr(priv, rxq);

	spin_unlock_irqrestore(&priv->lock, flags);

	/* Allocate or reset and init all Tx and Command queues */
	if (!priv->txq) {
		ret = iwlagn_txq_ctx_alloc(priv);
		if (ret)
			return ret;
	} else
		iwlagn_txq_ctx_reset(priv);

	set_bit(STATUS_INIT, &priv->status);

	return 0;
}

/**
 * iwlagn_dma_addr2rbd_ptr - convert a DMA address to a uCode read buffer ptr
 */
static inline __le32 iwlagn_dma_addr2rbd_ptr(struct iwl_priv *priv,
					  dma_addr_t dma_addr)
{
	return cpu_to_le32((u32)(dma_addr >> 8));
}

/**
 * iwlagn_rx_queue_restock - refill RX queue from pre-allocated pool
 *
 * If there are slots in the RX queue that need to be restocked,
 * and we have free pre-allocated buffers, fill the ranks as much
 * as we can, pulling from rx_free.
 *
 * This moves the 'write' index forward to catch up with 'processed', and
 * also updates the memory address in the firmware to reference the new
 * target buffer.
 */
void iwlagn_rx_queue_restock(struct iwl_priv *priv)
{
	struct iwl_rx_queue *rxq = &priv->rxq;
	struct list_head *element;
	struct iwl_rx_mem_buffer *rxb;
	unsigned long flags;

	spin_lock_irqsave(&rxq->lock, flags);
	while ((iwl_rx_queue_space(rxq) > 0) && (rxq->free_count)) {
		/* The overwritten rxb must be a used one */
		rxb = rxq->queue[rxq->write];
		BUG_ON(rxb && rxb->page);

		/* Get next free Rx buffer, remove from free list */
		element = rxq->rx_free.next;
		rxb = list_entry(element, struct iwl_rx_mem_buffer, list);
		list_del(element);

		/* Point to Rx buffer via next RBD in circular buffer */
		rxq->bd[rxq->write] = iwlagn_dma_addr2rbd_ptr(priv,
							      rxb->page_dma);
		rxq->queue[rxq->write] = rxb;
		rxq->write = (rxq->write + 1) & RX_QUEUE_MASK;
		rxq->free_count--;
	}
	spin_unlock_irqrestore(&rxq->lock, flags);
	/* If the pre-allocated buffer pool is dropping low, schedule to
	 * refill it */
	if (rxq->free_count <= RX_LOW_WATERMARK)
		queue_work(priv->workqueue, &priv->rx_replenish);


	/* If we've added more space for the firmware to place data, tell it.
	 * Increment device's write pointer in multiples of 8. */
	if (rxq->write_actual != (rxq->write & ~0x7)) {
		spin_lock_irqsave(&rxq->lock, flags);
		rxq->need_update = 1;
		spin_unlock_irqrestore(&rxq->lock, flags);
		iwl_rx_queue_update_write_ptr(priv, rxq);
	}
}

/**
 * iwlagn_rx_replenish - Move all used packet from rx_used to rx_free
 *
 * When moving to rx_free an SKB is allocated for the slot.
 *
 * Also restock the Rx queue via iwl_rx_queue_restock.
 * This is called as a scheduled work item (except for during initialization)
 */
void iwlagn_rx_allocate(struct iwl_priv *priv, gfp_t priority)
{
	struct iwl_rx_queue *rxq = &priv->rxq;
	struct list_head *element;
	struct iwl_rx_mem_buffer *rxb;
	struct page *page;
	unsigned long flags;
	gfp_t gfp_mask = priority;

	while (1) {
		spin_lock_irqsave(&rxq->lock, flags);
		if (list_empty(&rxq->rx_used)) {
			spin_unlock_irqrestore(&rxq->lock, flags);
			return;
		}
		spin_unlock_irqrestore(&rxq->lock, flags);

		if (rxq->free_count > RX_LOW_WATERMARK)
			gfp_mask |= __GFP_NOWARN;

		if (priv->hw_params.rx_page_order > 0)
			gfp_mask |= __GFP_COMP;

		/* Alloc a new receive buffer */
		page = alloc_pages(gfp_mask, priv->hw_params.rx_page_order);
		if (!page) {
			if (net_ratelimit())
				IWL_DEBUG_INFO(priv, "alloc_pages failed, "
					       "order: %d\n",
					       priv->hw_params.rx_page_order);

			if ((rxq->free_count <= RX_LOW_WATERMARK) &&
			    net_ratelimit())
				IWL_CRIT(priv, "Failed to alloc_pages with %s. Only %u free buffers remaining.\n",
					 priority == GFP_ATOMIC ?  "GFP_ATOMIC" : "GFP_KERNEL",
					 rxq->free_count);
			/* We don't reschedule replenish work here -- we will
			 * call the restock method and if it still needs
			 * more buffers it will schedule replenish */
			return;
		}

		spin_lock_irqsave(&rxq->lock, flags);

		if (list_empty(&rxq->rx_used)) {
			spin_unlock_irqrestore(&rxq->lock, flags);
			__free_pages(page, priv->hw_params.rx_page_order);
			return;
		}
		element = rxq->rx_used.next;
		rxb = list_entry(element, struct iwl_rx_mem_buffer, list);
		list_del(element);

		spin_unlock_irqrestore(&rxq->lock, flags);

		BUG_ON(rxb->page);
		rxb->page = page;
		/* Get physical address of the RB */
		rxb->page_dma = pci_map_page(priv->pci_dev, page, 0,
				PAGE_SIZE << priv->hw_params.rx_page_order,
				PCI_DMA_FROMDEVICE);
		/* dma address must be no more than 36 bits */
		BUG_ON(rxb->page_dma & ~DMA_BIT_MASK(36));
		/* and also 256 byte aligned! */
		BUG_ON(rxb->page_dma & DMA_BIT_MASK(8));

		spin_lock_irqsave(&rxq->lock, flags);

		list_add_tail(&rxb->list, &rxq->rx_free);
		rxq->free_count++;
		priv->alloc_rxb_page++;

		spin_unlock_irqrestore(&rxq->lock, flags);
	}
}

void iwlagn_rx_replenish(struct iwl_priv *priv)
{
	unsigned long flags;

	iwlagn_rx_allocate(priv, GFP_KERNEL);

	spin_lock_irqsave(&priv->lock, flags);
	iwlagn_rx_queue_restock(priv);
	spin_unlock_irqrestore(&priv->lock, flags);
}

void iwlagn_rx_replenish_now(struct iwl_priv *priv)
{
	iwlagn_rx_allocate(priv, GFP_ATOMIC);

	iwlagn_rx_queue_restock(priv);
}

/* Assumes that the skb field of the buffers in 'pool' is kept accurate.
 * If an SKB has been detached, the POOL needs to have its SKB set to NULL
 * This free routine walks the list of POOL entries and if SKB is set to
 * non NULL it is unmapped and freed
 */
void iwlagn_rx_queue_free(struct iwl_priv *priv, struct iwl_rx_queue *rxq)
{
	int i;
	for (i = 0; i < RX_QUEUE_SIZE + RX_FREE_BUFFERS; i++) {
		if (rxq->pool[i].page != NULL) {
			pci_unmap_page(priv->pci_dev, rxq->pool[i].page_dma,
				PAGE_SIZE << priv->hw_params.rx_page_order,
				PCI_DMA_FROMDEVICE);
			__iwl_free_pages(priv, rxq->pool[i].page);
			rxq->pool[i].page = NULL;
		}
	}

	dma_free_coherent(&priv->pci_dev->dev, 4 * RX_QUEUE_SIZE, rxq->bd,
			  rxq->dma_addr);
	dma_free_coherent(&priv->pci_dev->dev, sizeof(struct iwl_rb_status),
			  rxq->rb_stts, rxq->rb_stts_dma);
	rxq->bd = NULL;
	rxq->rb_stts  = NULL;
}

int iwlagn_rxq_stop(struct iwl_priv *priv)
{

	/* stop Rx DMA */
	iwl_write_direct32(priv, FH_MEM_RCSR_CHNL0_CONFIG_REG, 0);
	iwl_poll_direct_bit(priv, FH_MEM_RSSR_RX_STATUS_REG,
			    FH_RSSR_CHNL0_RX_STATUS_CHNL_IDLE, 1000);

	return 0;
}

int iwlagn_hwrate_to_mac80211_idx(u32 rate_n_flags, enum ieee80211_band band)
{
	int idx = 0;
	int band_offset = 0;

	/* HT rate format: mac80211 wants an MCS number, which is just LSB */
	if (rate_n_flags & RATE_MCS_HT_MSK) {
		idx = (rate_n_flags & 0xff);
		return idx;
	/* Legacy rate format, search for match in table */
	} else {
		if (band == IEEE80211_BAND_5GHZ)
			band_offset = IWL_FIRST_OFDM_RATE;
		for (idx = band_offset; idx < IWL_RATE_COUNT_LEGACY; idx++)
			if (iwl_rates[idx].plcp == (rate_n_flags & 0xFF))
				return idx - band_offset;
	}

	return -1;
}

/* Calc max signal level (dBm) among 3 possible receivers */
static inline int iwlagn_calc_rssi(struct iwl_priv *priv,
				struct iwl_rx_phy_res *rx_resp)
{
	return priv->cfg->ops->utils->calc_rssi(priv, rx_resp);
}

#ifdef CONFIG_IWLWIFI_DEBUG
/**
 * iwlagn_dbg_report_frame - dump frame to syslog during debug sessions
 *
 * You may hack this function to show different aspects of received frames,
 * including selective frame dumps.
 * group100 parameter selects whether to show 1 out of 100 good data frames.
 *    All beacon and probe response frames are printed.
 */
static void iwlagn_dbg_report_frame(struct iwl_priv *priv,
		      struct iwl_rx_phy_res *phy_res, u16 length,
		      struct ieee80211_hdr *header, int group100)
{
	u32 to_us;
	u32 print_summary = 0;
	u32 print_dump = 0;	/* set to 1 to dump all frames' contents */
	u32 hundred = 0;
	u32 dataframe = 0;
	__le16 fc;
	u16 seq_ctl;
	u16 channel;
	u16 phy_flags;
	u32 rate_n_flags;
	u32 tsf_low;
	int rssi;

	if (likely(!(iwl_get_debug_level(priv) & IWL_DL_RX)))
		return;

	/* MAC header */
	fc = header->frame_control;
	seq_ctl = le16_to_cpu(header->seq_ctrl);

	/* metadata */
	channel = le16_to_cpu(phy_res->channel);
	phy_flags = le16_to_cpu(phy_res->phy_flags);
	rate_n_flags = le32_to_cpu(phy_res->rate_n_flags);

	/* signal statistics */
	rssi = iwlagn_calc_rssi(priv, phy_res);
	tsf_low = le64_to_cpu(phy_res->timestamp) & 0x0ffffffff;

	to_us = !compare_ether_addr(header->addr1, priv->mac_addr);

	/* if data frame is to us and all is good,
	 *   (optionally) print summary for only 1 out of every 100 */
	if (to_us && (fc & ~cpu_to_le16(IEEE80211_FCTL_PROTECTED)) ==
	    cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FTYPE_DATA)) {
		dataframe = 1;
		if (!group100)
			print_summary = 1;	/* print each frame */
		else if (priv->framecnt_to_us < 100) {
			priv->framecnt_to_us++;
			print_summary = 0;
		} else {
			priv->framecnt_to_us = 0;
			print_summary = 1;
			hundred = 1;
		}
	} else {
		/* print summary for all other frames */
		print_summary = 1;
	}

	if (print_summary) {
		char *title;
		int rate_idx;
		u32 bitrate;

		if (hundred)
			title = "100Frames";
		else if (ieee80211_has_retry(fc))
			title = "Retry";
		else if (ieee80211_is_assoc_resp(fc))
			title = "AscRsp";
		else if (ieee80211_is_reassoc_resp(fc))
			title = "RasRsp";
		else if (ieee80211_is_probe_resp(fc)) {
			title = "PrbRsp";
			print_dump = 1;	/* dump frame contents */
		} else if (ieee80211_is_beacon(fc)) {
			title = "Beacon";
			print_dump = 1;	/* dump frame contents */
		} else if (ieee80211_is_atim(fc))
			title = "ATIM";
		else if (ieee80211_is_auth(fc))
			title = "Auth";
		else if (ieee80211_is_deauth(fc))
			title = "DeAuth";
		else if (ieee80211_is_disassoc(fc))
			title = "DisAssoc";
		else
			title = "Frame";

		rate_idx = iwl_hwrate_to_plcp_idx(rate_n_flags);
		if (unlikely((rate_idx < 0) || (rate_idx >= IWL_RATE_COUNT))) {
			bitrate = 0;
			WARN_ON_ONCE(1);
		} else {
			bitrate = iwl_rates[rate_idx].ieee / 2;
		}

		/* print frame summary.
		 * MAC addresses show just the last byte (for brevity),
		 *    but you can hack it to show more, if you'd like to. */
		if (dataframe)
			IWL_DEBUG_RX(priv, "%s: mhd=0x%04x, dst=0x%02x, "
				     "len=%u, rssi=%d, chnl=%d, rate=%u,\n",
				     title, le16_to_cpu(fc), header->addr1[5],
				     length, rssi, channel, bitrate);
		else {
			/* src/dst addresses assume managed mode */
			IWL_DEBUG_RX(priv, "%s: 0x%04x, dst=0x%02x, src=0x%02x, "
				     "len=%u, rssi=%d, tim=%lu usec, "
				     "phy=0x%02x, chnl=%d\n",
				     title, le16_to_cpu(fc), header->addr1[5],
				     header->addr3[5], length, rssi,
				     tsf_low - priv->scan_start_tsf,
				     phy_flags, channel);
		}
	}
	if (print_dump)
		iwl_print_hex_dump(priv, IWL_DL_RX, header, length);
}
#endif

static u32 iwlagn_translate_rx_status(struct iwl_priv *priv, u32 decrypt_in)
{
	u32 decrypt_out = 0;

	if ((decrypt_in & RX_RES_STATUS_STATION_FOUND) ==
					RX_RES_STATUS_STATION_FOUND)
		decrypt_out |= (RX_RES_STATUS_STATION_FOUND |
				RX_RES_STATUS_NO_STATION_INFO_MISMATCH);

	decrypt_out |= (decrypt_in & RX_RES_STATUS_SEC_TYPE_MSK);

	/* packet was not encrypted */
	if ((decrypt_in & RX_RES_STATUS_SEC_TYPE_MSK) ==
					RX_RES_STATUS_SEC_TYPE_NONE)
		return decrypt_out;

	/* packet was encrypted with unknown alg */
	if ((decrypt_in & RX_RES_STATUS_SEC_TYPE_MSK) ==
					RX_RES_STATUS_SEC_TYPE_ERR)
		return decrypt_out;

	/* decryption was not done in HW */
	if ((decrypt_in & RX_MPDU_RES_STATUS_DEC_DONE_MSK) !=
					RX_MPDU_RES_STATUS_DEC_DONE_MSK)
		return decrypt_out;

	switch (decrypt_in & RX_RES_STATUS_SEC_TYPE_MSK) {

	case RX_RES_STATUS_SEC_TYPE_CCMP:
		/* alg is CCM: check MIC only */
		if (!(decrypt_in & RX_MPDU_RES_STATUS_MIC_OK))
			/* Bad MIC */
			decrypt_out |= RX_RES_STATUS_BAD_ICV_MIC;
		else
			decrypt_out |= RX_RES_STATUS_DECRYPT_OK;

		break;

	case RX_RES_STATUS_SEC_TYPE_TKIP:
		if (!(decrypt_in & RX_MPDU_RES_STATUS_TTAK_OK)) {
			/* Bad TTAK */
			decrypt_out |= RX_RES_STATUS_BAD_KEY_TTAK;
			break;
		}
		/* fall through if TTAK OK */
	default:
		if (!(decrypt_in & RX_MPDU_RES_STATUS_ICV_OK))
			decrypt_out |= RX_RES_STATUS_BAD_ICV_MIC;
		else
			decrypt_out |= RX_RES_STATUS_DECRYPT_OK;
		break;
	};

	IWL_DEBUG_RX(priv, "decrypt_in:0x%x  decrypt_out = 0x%x\n",
					decrypt_in, decrypt_out);

	return decrypt_out;
}

static void iwlagn_pass_packet_to_mac80211(struct iwl_priv *priv,
					struct ieee80211_hdr *hdr,
					u16 len,
					u32 ampdu_status,
					struct iwl_rx_mem_buffer *rxb,
					struct ieee80211_rx_status *stats)
{
	struct sk_buff *skb;
	__le16 fc = hdr->frame_control;

	/* We only process data packets if the interface is open */
	if (unlikely(!priv->is_open)) {
		IWL_DEBUG_DROP_LIMIT(priv,
		    "Dropping packet while interface is not open.\n");
		return;
	}

	/* In case of HW accelerated crypto and bad decryption, drop */
	if (!priv->cfg->mod_params->sw_crypto &&
	    iwl_set_decrypted_flag(priv, hdr, ampdu_status, stats))
		return;

	skb = dev_alloc_skb(128);
	if (!skb) {
		IWL_ERR(priv, "dev_alloc_skb failed\n");
		return;
	}

	skb_add_rx_frag(skb, 0, rxb->page, (void *)hdr - rxb_addr(rxb), len);

	iwl_update_stats(priv, false, fc, len);
	memcpy(IEEE80211_SKB_RXCB(skb), stats, sizeof(*stats));

	ieee80211_rx(priv->hw, skb);
	priv->alloc_rxb_page--;
	rxb->page = NULL;
}

/* Called for REPLY_RX (legacy ABG frames), or
 * REPLY_RX_MPDU_CMD (HT high-throughput N frames). */
void iwlagn_rx_reply_rx(struct iwl_priv *priv,
				struct iwl_rx_mem_buffer *rxb)
{
	struct ieee80211_hdr *header;
	struct ieee80211_rx_status rx_status;
	struct iwl_rx_packet *pkt = rxb_addr(rxb);
	struct iwl_rx_phy_res *phy_res;
	__le32 rx_pkt_status;
	struct iwl4965_rx_mpdu_res_start *amsdu;
	u32 len;
	u32 ampdu_status;
	u32 rate_n_flags;

	/**
	 * REPLY_RX and REPLY_RX_MPDU_CMD are handled differently.
	 *	REPLY_RX: physical layer info is in this buffer
	 *	REPLY_RX_MPDU_CMD: physical layer info was sent in separate
	 *		command and cached in priv->last_phy_res
	 *
	 * Here we set up local variables depending on which command is
	 * received.
	 */
	if (pkt->hdr.cmd == REPLY_RX) {
		phy_res = (struct iwl_rx_phy_res *)pkt->u.raw;
		header = (struct ieee80211_hdr *)(pkt->u.raw + sizeof(*phy_res)
				+ phy_res->cfg_phy_cnt);

		len = le16_to_cpu(phy_res->byte_count);
		rx_pkt_status = *(__le32 *)(pkt->u.raw + sizeof(*phy_res) +
				phy_res->cfg_phy_cnt + len);
		ampdu_status = le32_to_cpu(rx_pkt_status);
	} else {
		if (!priv->_agn.last_phy_res_valid) {
			IWL_ERR(priv, "MPDU frame without cached PHY data\n");
			return;
		}
		phy_res = &priv->_agn.last_phy_res;
		amsdu = (struct iwl4965_rx_mpdu_res_start *)pkt->u.raw;
		header = (struct ieee80211_hdr *)(pkt->u.raw + sizeof(*amsdu));
		len = le16_to_cpu(amsdu->byte_count);
		rx_pkt_status = *(__le32 *)(pkt->u.raw + sizeof(*amsdu) + len);
		ampdu_status = iwlagn_translate_rx_status(priv,
				le32_to_cpu(rx_pkt_status));
	}

	if ((unlikely(phy_res->cfg_phy_cnt > 20))) {
		IWL_DEBUG_DROP(priv, "dsp size out of range [0,20]: %d/n",
				phy_res->cfg_phy_cnt);
		return;
	}

	if (!(rx_pkt_status & RX_RES_STATUS_NO_CRC32_ERROR) ||
	    !(rx_pkt_status & RX_RES_STATUS_NO_RXE_OVERFLOW)) {
		IWL_DEBUG_RX(priv, "Bad CRC or FIFO: 0x%08X.\n",
				le32_to_cpu(rx_pkt_status));
		return;
	}

	/* This will be used in several places later */
	rate_n_flags = le32_to_cpu(phy_res->rate_n_flags);

	/* rx_status carries information about the packet to mac80211 */
	rx_status.mactime = le64_to_cpu(phy_res->timestamp);
	rx_status.freq =
		ieee80211_channel_to_frequency(le16_to_cpu(phy_res->channel));
	rx_status.band = (phy_res->phy_flags & RX_RES_PHY_FLAGS_BAND_24_MSK) ?
				IEEE80211_BAND_2GHZ : IEEE80211_BAND_5GHZ;
	rx_status.rate_idx =
		iwlagn_hwrate_to_mac80211_idx(rate_n_flags, rx_status.band);
	rx_status.flag = 0;

	/* TSF isn't reliable. In order to allow smooth user experience,
	 * this W/A doesn't propagate it to the mac80211 */
	/*rx_status.flag |= RX_FLAG_TSFT;*/

	priv->ucode_beacon_time = le32_to_cpu(phy_res->beacon_time_stamp);

	/* Find max signal strength (dBm) among 3 antenna/receiver chains */
	rx_status.signal = iwlagn_calc_rssi(priv, phy_res);

#ifdef CONFIG_IWLWIFI_DEBUG
	/* Set "1" to report good data frames in groups of 100 */
	if (unlikely(iwl_get_debug_level(priv) & IWL_DL_RX))
		iwlagn_dbg_report_frame(priv, phy_res, len, header, 1);
#endif
	iwl_dbg_log_rx_data_frame(priv, len, header);
	IWL_DEBUG_STATS_LIMIT(priv, "Rssi %d, TSF %llu\n",
		rx_status.signal, (unsigned long long)rx_status.mactime);

	/*
	 * "antenna number"
	 *
	 * It seems that the antenna field in the phy flags value
	 * is actually a bit field. This is undefined by radiotap,
	 * it wants an actual antenna number but I always get "7"
	 * for most legacy frames I receive indicating that the
	 * same frame was received on all three RX chains.
	 *
	 * I think this field should be removed in favor of a
	 * new 802.11n radiotap field "RX chains" that is defined
	 * as a bitmask.
	 */
	rx_status.antenna =
		(le16_to_cpu(phy_res->phy_flags) & RX_RES_PHY_FLAGS_ANTENNA_MSK)
		>> RX_RES_PHY_FLAGS_ANTENNA_POS;

	/* set the preamble flag if appropriate */
	if (phy_res->phy_flags & RX_RES_PHY_FLAGS_SHORT_PREAMBLE_MSK)
		rx_status.flag |= RX_FLAG_SHORTPRE;

	/* Set up the HT phy flags */
	if (rate_n_flags & RATE_MCS_HT_MSK)
		rx_status.flag |= RX_FLAG_HT;
	if (rate_n_flags & RATE_MCS_HT40_MSK)
		rx_status.flag |= RX_FLAG_40MHZ;
	if (rate_n_flags & RATE_MCS_SGI_MSK)
		rx_status.flag |= RX_FLAG_SHORT_GI;

	iwlagn_pass_packet_to_mac80211(priv, header, len, ampdu_status,
				    rxb, &rx_status);
}

/* Cache phy data (Rx signal strength, etc) for HT frame (REPLY_RX_PHY_CMD).
 * This will be used later in iwl_rx_reply_rx() for REPLY_RX_MPDU_CMD. */
void iwlagn_rx_reply_rx_phy(struct iwl_priv *priv,
			    struct iwl_rx_mem_buffer *rxb)
{
	struct iwl_rx_packet *pkt = rxb_addr(rxb);
	priv->_agn.last_phy_res_valid = true;
	memcpy(&priv->_agn.last_phy_res, pkt->u.raw,
	       sizeof(struct iwl_rx_phy_res));
}

static int iwl_get_single_channel_for_scan(struct iwl_priv *priv,
				     enum ieee80211_band band,
				     struct iwl_scan_channel *scan_ch)
{
	const struct ieee80211_supported_band *sband;
	const struct iwl_channel_info *ch_info;
	u16 passive_dwell = 0;
	u16 active_dwell = 0;
	int i, added = 0;
	u16 channel = 0;

	sband = iwl_get_hw_mode(priv, band);
	if (!sband) {
		IWL_ERR(priv, "invalid band\n");
		return added;
	}

	active_dwell = iwl_get_active_dwell_time(priv, band, 0);
	passive_dwell = iwl_get_passive_dwell_time(priv, band);

	if (passive_dwell <= active_dwell)
		passive_dwell = active_dwell + 1;

	/* only scan single channel, good enough to reset the RF */
	/* pick the first valid not in-use channel */
	if (band == IEEE80211_BAND_5GHZ) {
		for (i = 14; i < priv->channel_count; i++) {
			if (priv->channel_info[i].channel !=
			    le16_to_cpu(priv->staging_rxon.channel)) {
				channel = priv->channel_info[i].channel;
				ch_info = iwl_get_channel_info(priv,
					band, channel);
				if (is_channel_valid(ch_info))
					break;
			}
		}
	} else {
		for (i = 0; i < 14; i++) {
			if (priv->channel_info[i].channel !=
			    le16_to_cpu(priv->staging_rxon.channel)) {
					channel =
						priv->channel_info[i].channel;
					ch_info = iwl_get_channel_info(priv,
						band, channel);
					if (is_channel_valid(ch_info))
						break;
			}
		}
	}
	if (channel) {
		scan_ch->channel = cpu_to_le16(channel);
		scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
		scan_ch->active_dwell = cpu_to_le16(active_dwell);
		scan_ch->passive_dwell = cpu_to_le16(passive_dwell);
		/* Set txpower levels to defaults */
		scan_ch->dsp_atten = 110;
		if (band == IEEE80211_BAND_5GHZ)
			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
		else
			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
		added++;
	} else
		IWL_ERR(priv, "no valid channel found\n");
	return added;
}

static int iwl_get_channels_for_scan(struct iwl_priv *priv,
				     enum ieee80211_band band,
				     u8 is_active, u8 n_probes,
				     struct iwl_scan_channel *scan_ch)
{
	struct ieee80211_channel *chan;
	const struct ieee80211_supported_band *sband;
	const struct iwl_channel_info *ch_info;
	u16 passive_dwell = 0;
	u16 active_dwell = 0;
	int added, i;
	u16 channel;

	sband = iwl_get_hw_mode(priv, band);
	if (!sband)
		return 0;

	active_dwell = iwl_get_active_dwell_time(priv, band, n_probes);
	passive_dwell = iwl_get_passive_dwell_time(priv, band);

	if (passive_dwell <= active_dwell)
		passive_dwell = active_dwell + 1;

	for (i = 0, added = 0; i < priv->scan_request->n_channels; i++) {
		chan = priv->scan_request->channels[i];

		if (chan->band != band)
			continue;

		channel = ieee80211_frequency_to_channel(chan->center_freq);
		scan_ch->channel = cpu_to_le16(channel);

		ch_info = iwl_get_channel_info(priv, band, channel);
		if (!is_channel_valid(ch_info)) {
			IWL_DEBUG_SCAN(priv, "Channel %d is INVALID for this band.\n",
					channel);
			continue;
		}

		if (!is_active || is_channel_passive(ch_info) ||
		    (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN))
			scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
		else
			scan_ch->type = SCAN_CHANNEL_TYPE_ACTIVE;

		if (n_probes)
			scan_ch->type |= IWL_SCAN_PROBE_MASK(n_probes);

		scan_ch->active_dwell = cpu_to_le16(active_dwell);
		scan_ch->passive_dwell = cpu_to_le16(passive_dwell);

		/* Set txpower levels to defaults */
		scan_ch->dsp_atten = 110;

		/* NOTE: if we were doing 6Mb OFDM for scans we'd use
		 * power level:
		 * scan_ch->tx_gain = ((1 << 5) | (2 << 3)) | 3;
		 */
		if (band == IEEE80211_BAND_5GHZ)
			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
		else
			scan_ch->tx_gain = ((1 << 5) | (5 << 3));

		IWL_DEBUG_SCAN(priv, "Scanning ch=%d prob=0x%X [%s %d]\n",
			       channel, le32_to_cpu(scan_ch->type),
			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
				"ACTIVE" : "PASSIVE",
			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
			       active_dwell : passive_dwell);

		scan_ch++;
		added++;
	}

	IWL_DEBUG_SCAN(priv, "total channels to scan %d\n", added);
	return added;
}

void iwlagn_request_scan(struct iwl_priv *priv)
{
	struct iwl_host_cmd cmd = {
		.id = REPLY_SCAN_CMD,
		.len = sizeof(struct iwl_scan_cmd),
		.flags = CMD_SIZE_HUGE,
	};
	struct iwl_scan_cmd *scan;
	struct ieee80211_conf *conf = NULL;
	u32 rate_flags = 0;
	u16 cmd_len;
	u16 rx_chain = 0;
	enum ieee80211_band band;
	u8 n_probes = 0;
	u8 rx_ant = priv->hw_params.valid_rx_ant;
	u8 rate;
	bool is_active = false;
	int  chan_mod;
	u8 active_chains;

	conf = ieee80211_get_hw_conf(priv->hw);

	cancel_delayed_work(&priv->scan_check);

	if (!iwl_is_ready(priv)) {
		IWL_WARN(priv, "request scan called when driver not ready.\n");
		goto done;
	}

	/* Make sure the scan wasn't canceled before this queued work
	 * was given the chance to run... */
	if (!test_bit(STATUS_SCANNING, &priv->status))
		goto done;

	/* This should never be called or scheduled if there is currently
	 * a scan active in the hardware. */
	if (test_bit(STATUS_SCAN_HW, &priv->status)) {
		IWL_DEBUG_INFO(priv, "Multiple concurrent scan requests in parallel. "
			       "Ignoring second request.\n");
		goto done;
	}

	if (test_bit(STATUS_EXIT_PENDING, &priv->status)) {
		IWL_DEBUG_SCAN(priv, "Aborting scan due to device shutdown\n");
		goto done;
	}

	if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
		IWL_DEBUG_HC(priv, "Scan request while abort pending.  Queuing.\n");
		goto done;
	}

	if (iwl_is_rfkill(priv)) {
		IWL_DEBUG_HC(priv, "Aborting scan due to RF Kill activation\n");
		goto done;
	}

	if (!test_bit(STATUS_READY, &priv->status)) {
		IWL_DEBUG_HC(priv, "Scan request while uninitialized.  Queuing.\n");
		goto done;
	}

	if (!priv->scan_cmd) {
		priv->scan_cmd = kmalloc(sizeof(struct iwl_scan_cmd) +
					 IWL_MAX_SCAN_SIZE, GFP_KERNEL);
		if (!priv->scan_cmd) {
			IWL_DEBUG_SCAN(priv,
				       "fail to allocate memory for scan\n");
			goto done;
		}
	}
	scan = priv->scan_cmd;
	memset(scan, 0, sizeof(struct iwl_scan_cmd) + IWL_MAX_SCAN_SIZE);

	scan->quiet_plcp_th = IWL_PLCP_QUIET_THRESH;
	scan->quiet_time = IWL_ACTIVE_QUIET_TIME;

	if (iwl_is_associated(priv)) {
		u16 interval = 0;
		u32 extra;
		u32 suspend_time = 100;
		u32 scan_suspend_time = 100;
		unsigned long flags;

		IWL_DEBUG_INFO(priv, "Scanning while associated...\n");
		spin_lock_irqsave(&priv->lock, flags);
		interval = priv->beacon_int;
		spin_unlock_irqrestore(&priv->lock, flags);

		scan->suspend_time = 0;
		scan->max_out_time = cpu_to_le32(200 * 1024);
		if (!interval)
			interval = suspend_time;

		extra = (suspend_time / interval) << 22;
		scan_suspend_time = (extra |
		    ((suspend_time % interval) * 1024));
		scan->suspend_time = cpu_to_le32(scan_suspend_time);
		IWL_DEBUG_SCAN(priv, "suspend_time 0x%X beacon interval %d\n",
			       scan_suspend_time, interval);
	}

	if (priv->is_internal_short_scan) {
		IWL_DEBUG_SCAN(priv, "Start internal passive scan.\n");
	} else if (priv->scan_request->n_ssids) {
		int i, p = 0;
		IWL_DEBUG_SCAN(priv, "Kicking off active scan\n");
		for (i = 0; i < priv->scan_request->n_ssids; i++) {
			/* always does wildcard anyway */
			if (!priv->scan_request->ssids[i].ssid_len)
				continue;
			scan->direct_scan[p].id = WLAN_EID_SSID;
			scan->direct_scan[p].len =
				priv->scan_request->ssids[i].ssid_len;
			memcpy(scan->direct_scan[p].ssid,
			       priv->scan_request->ssids[i].ssid,
			       priv->scan_request->ssids[i].ssid_len);
			n_probes++;
			p++;
		}
		is_active = true;
	} else
		IWL_DEBUG_SCAN(priv, "Start passive scan.\n");

	scan->tx_cmd.tx_flags = TX_CMD_FLG_SEQ_CTL_MSK;
	scan->tx_cmd.sta_id = priv->hw_params.bcast_sta_id;
	scan->tx_cmd.stop_time.life_time = TX_CMD_LIFE_TIME_INFINITE;

	switch (priv->scan_band) {
	case IEEE80211_BAND_2GHZ:
		scan->flags = RXON_FLG_BAND_24G_MSK | RXON_FLG_AUTO_DETECT_MSK;
		chan_mod = le32_to_cpu(priv->active_rxon.flags & RXON_FLG_CHANNEL_MODE_MSK)
				       >> RXON_FLG_CHANNEL_MODE_POS;
		if (chan_mod == CHANNEL_MODE_PURE_40) {
			rate = IWL_RATE_6M_PLCP;
		} else {
			rate = IWL_RATE_1M_PLCP;
			rate_flags = RATE_MCS_CCK_MSK;
		}
		scan->good_CRC_th = IWL_GOOD_CRC_TH_DISABLED;
		break;
	case IEEE80211_BAND_5GHZ:
		rate = IWL_RATE_6M_PLCP;
		/*
		 * If active scanning is requested but a certain channel is
		 * marked passive, we can do active scanning if we detect
		 * transmissions.
		 *
		 * There is an issue with some firmware versions that triggers
		 * a sysassert on a "good CRC threshold" of zero (== disabled),
		 * on a radar channel even though this means that we should NOT
		 * send probes.
		 *
		 * The "good CRC threshold" is the number of frames that we
		 * need to receive during our dwell time on a channel before
		 * sending out probes -- setting this to a huge value will
		 * mean we never reach it, but at the same time work around
		 * the aforementioned issue. Thus use IWL_GOOD_CRC_TH_NEVER
		 * here instead of IWL_GOOD_CRC_TH_DISABLED.
		 */
		scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
						IWL_GOOD_CRC_TH_NEVER;
		break;
	default:
		IWL_WARN(priv, "Invalid scan band count\n");
		goto done;
	}

	band = priv->scan_band;

	if (priv->cfg->scan_antennas[band])
		rx_ant = priv->cfg->scan_antennas[band];

	priv->scan_tx_ant[band] =
			iwl_toggle_tx_ant(priv, priv->scan_tx_ant[band]);
	rate_flags |= iwl_ant_idx_to_flags(priv->scan_tx_ant[band]);
	scan->tx_cmd.rate_n_flags = iwl_hw_set_rate_n_flags(rate, rate_flags);

	/* In power save mode use one chain, otherwise use all chains */
	if (test_bit(STATUS_POWER_PMI, &priv->status)) {
		/* rx_ant has been set to all valid chains previously */
		active_chains = rx_ant &
				((u8)(priv->chain_noise_data.active_chains));
		if (!active_chains)
			active_chains = rx_ant;

		IWL_DEBUG_SCAN(priv, "chain_noise_data.active_chains: %u\n",
				priv->chain_noise_data.active_chains);

		rx_ant = first_antenna(active_chains);
	}
	/* MIMO is not used here, but value is required */
	rx_chain |= priv->hw_params.valid_rx_ant << RXON_RX_CHAIN_VALID_POS;
	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_MIMO_SEL_POS;
	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_SEL_POS;
	rx_chain |= 0x1 << RXON_RX_CHAIN_DRIVER_FORCE_POS;
	scan->rx_chain = cpu_to_le16(rx_chain);
	if (!priv->is_internal_short_scan) {
		cmd_len = iwl_fill_probe_req(priv,
					(struct ieee80211_mgmt *)scan->data,
					priv->scan_request->ie,
					priv->scan_request->ie_len,
					IWL_MAX_SCAN_SIZE - sizeof(*scan));
	} else {
		cmd_len = iwl_fill_probe_req(priv,
					(struct ieee80211_mgmt *)scan->data,
					NULL, 0,
					IWL_MAX_SCAN_SIZE - sizeof(*scan));

	}
	scan->tx_cmd.len = cpu_to_le16(cmd_len);

	scan->filter_flags |= (RXON_FILTER_ACCEPT_GRP_MSK |
			       RXON_FILTER_BCON_AWARE_MSK);

	if (priv->is_internal_short_scan) {
		scan->channel_count =
			iwl_get_single_channel_for_scan(priv, band,
				(void *)&scan->data[le16_to_cpu(
				scan->tx_cmd.len)]);
	} else {
		scan->channel_count =
			iwl_get_channels_for_scan(priv, band,
				is_active, n_probes,
				(void *)&scan->data[le16_to_cpu(
				scan->tx_cmd.len)]);
	}
	if (scan->channel_count == 0) {
		IWL_DEBUG_SCAN(priv, "channel count %d\n", scan->channel_count);
		goto done;
	}

	cmd.len += le16_to_cpu(scan->tx_cmd.len) +
	    scan->channel_count * sizeof(struct iwl_scan_channel);
	cmd.data = scan;
	scan->len = cpu_to_le16(cmd.len);

	set_bit(STATUS_SCAN_HW, &priv->status);
	if (iwl_send_cmd_sync(priv, &cmd))
		goto done;

	queue_delayed_work(priv->workqueue, &priv->scan_check,
			   IWL_SCAN_CHECK_WATCHDOG);

	return;

 done:
	/* Cannot perform scan. Make sure we clear scanning
	* bits from status so next scan request can be performed.
	* If we don't clear scanning status bit here all next scan
	* will fail
	*/
	clear_bit(STATUS_SCAN_HW, &priv->status);
	clear_bit(STATUS_SCANNING, &priv->status);
	/* inform mac80211 scan aborted */
	queue_work(priv->workqueue, &priv->scan_completed);
}