iwl-agn.c

/******************************************************************************
 *
 * Copyright(c) 2003 - 2011 Intel Corporation. All rights reserved.
 *
 * Portions of this file are derived from the ipw3945 project, as well
 * as portions of the ieee80211 subsystem header files.
 *
 * 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.
 *
 * Contact Information:
 *  Intel Linux Wireless <ilw@linux.intel.com>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 *****************************************************************************/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/pci-aspm.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/wireless.h>
#include <linux/firmware.h>
#include <linux/etherdevice.h>
#include <linux/if_arp.h>

#include <net/mac80211.h>

#include <asm/div64.h>

#define DRV_NAME        "iwlagn"

#include "iwl-eeprom.h"
#include "iwl-dev.h"
#include "iwl-core.h"
#include "iwl-io.h"
#include "iwl-helpers.h"
#include "iwl-sta.h"
#include "iwl-agn-calib.h"
#include "iwl-agn.h"


/******************************************************************************
 *
 * module boiler plate
 *
 ******************************************************************************/

/*
 * module name, copyright, version, etc.
 */
#define DRV_DESCRIPTION	"Intel(R) Wireless WiFi Link AGN driver for Linux"

#ifdef CONFIG_IWLWIFI_DEBUG
#define VD "d"
#else
#define VD
#endif

#define DRV_VERSION     IWLWIFI_VERSION VD


MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_VERSION(DRV_VERSION);
MODULE_AUTHOR(DRV_COPYRIGHT " " DRV_AUTHOR);
MODULE_LICENSE("GPL");

static int iwlagn_ant_coupling;
static bool iwlagn_bt_ch_announce = 1;

void iwl_update_chain_flags(struct iwl_priv *priv)
{
	struct iwl_rxon_context *ctx;

	if (priv->cfg->ops->hcmd->set_rxon_chain) {
		for_each_context(priv, ctx) {
			priv->cfg->ops->hcmd->set_rxon_chain(priv, ctx);
			if (ctx->active.rx_chain != ctx->staging.rx_chain)
				iwlcore_commit_rxon(priv, ctx);
		}
	}
}

static void iwl_clear_free_frames(struct iwl_priv *priv)
{
	struct list_head *element;

	IWL_DEBUG_INFO(priv, "%d frames on pre-allocated heap on clear.\n",
		       priv->frames_count);

	while (!list_empty(&priv->free_frames)) {
		element = priv->free_frames.next;
		list_del(element);
		kfree(list_entry(element, struct iwl_frame, list));
		priv->frames_count--;
	}

	if (priv->frames_count) {
		IWL_WARN(priv, "%d frames still in use.  Did we lose one?\n",
			    priv->frames_count);
		priv->frames_count = 0;
	}
}

static struct iwl_frame *iwl_get_free_frame(struct iwl_priv *priv)
{
	struct iwl_frame *frame;
	struct list_head *element;
	if (list_empty(&priv->free_frames)) {
		frame = kzalloc(sizeof(*frame), GFP_KERNEL);
		if (!frame) {
			IWL_ERR(priv, "Could not allocate frame!\n");
			return NULL;
		}

		priv->frames_count++;
		return frame;
	}

	element = priv->free_frames.next;
	list_del(element);
	return list_entry(element, struct iwl_frame, list);
}

static void iwl_free_frame(struct iwl_priv *priv, struct iwl_frame *frame)
{
	memset(frame, 0, sizeof(*frame));
	list_add(&frame->list, &priv->free_frames);
}

static u32 iwl_fill_beacon_frame(struct iwl_priv *priv,
				 struct ieee80211_hdr *hdr,
				 int left)
{
	lockdep_assert_held(&priv->mutex);

	if (!priv->beacon_skb)
		return 0;

	if (priv->beacon_skb->len > left)
		return 0;

	memcpy(hdr, priv->beacon_skb->data, priv->beacon_skb->len);

	return priv->beacon_skb->len;
}

/* Parse the beacon frame to find the TIM element and set tim_idx & tim_size */
static void iwl_set_beacon_tim(struct iwl_priv *priv,
			       struct iwl_tx_beacon_cmd *tx_beacon_cmd,
			       u8 *beacon, u32 frame_size)
{
	u16 tim_idx;
	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *)beacon;

	/*
	 * The index is relative to frame start but we start looking at the
	 * variable-length part of the beacon.
	 */
	tim_idx = mgmt->u.beacon.variable - beacon;

	/* Parse variable-length elements of beacon to find WLAN_EID_TIM */
	while ((tim_idx < (frame_size - 2)) &&
			(beacon[tim_idx] != WLAN_EID_TIM))
		tim_idx += beacon[tim_idx+1] + 2;

	/* If TIM field was found, set variables */
	if ((tim_idx < (frame_size - 1)) && (beacon[tim_idx] == WLAN_EID_TIM)) {
		tx_beacon_cmd->tim_idx = cpu_to_le16(tim_idx);
		tx_beacon_cmd->tim_size = beacon[tim_idx+1];
	} else
		IWL_WARN(priv, "Unable to find TIM Element in beacon\n");
}

static unsigned int iwl_hw_get_beacon_cmd(struct iwl_priv *priv,
				       struct iwl_frame *frame)
{
	struct iwl_tx_beacon_cmd *tx_beacon_cmd;
	u32 frame_size;
	u32 rate_flags;
	u32 rate;
	/*
	 * We have to set up the TX command, the TX Beacon command, and the
	 * beacon contents.
	 */

	lockdep_assert_held(&priv->mutex);

	if (!priv->beacon_ctx) {
		IWL_ERR(priv, "trying to build beacon w/o beacon context!\n");
		return 0;
	}

	/* Initialize memory */
	tx_beacon_cmd = &frame->u.beacon;
	memset(tx_beacon_cmd, 0, sizeof(*tx_beacon_cmd));

	/* Set up TX beacon contents */
	frame_size = iwl_fill_beacon_frame(priv, tx_beacon_cmd->frame,
				sizeof(frame->u) - sizeof(*tx_beacon_cmd));
	if (WARN_ON_ONCE(frame_size > MAX_MPDU_SIZE))
		return 0;
	if (!frame_size)
		return 0;

	/* Set up TX command fields */
	tx_beacon_cmd->tx.len = cpu_to_le16((u16)frame_size);
	tx_beacon_cmd->tx.sta_id = priv->beacon_ctx->bcast_sta_id;
	tx_beacon_cmd->tx.stop_time.life_time = TX_CMD_LIFE_TIME_INFINITE;
	tx_beacon_cmd->tx.tx_flags = TX_CMD_FLG_SEQ_CTL_MSK |
		TX_CMD_FLG_TSF_MSK | TX_CMD_FLG_STA_RATE_MSK;

	/* Set up TX beacon command fields */
	iwl_set_beacon_tim(priv, tx_beacon_cmd, (u8 *)tx_beacon_cmd->frame,
			   frame_size);

	/* Set up packet rate and flags */
	rate = iwl_rate_get_lowest_plcp(priv, priv->beacon_ctx);
	priv->mgmt_tx_ant = iwl_toggle_tx_ant(priv, priv->mgmt_tx_ant,
					      priv->hw_params.valid_tx_ant);
	rate_flags = iwl_ant_idx_to_flags(priv->mgmt_tx_ant);
	if ((rate >= IWL_FIRST_CCK_RATE) && (rate <= IWL_LAST_CCK_RATE))
		rate_flags |= RATE_MCS_CCK_MSK;
	tx_beacon_cmd->tx.rate_n_flags = iwl_hw_set_rate_n_flags(rate,
			rate_flags);

	return sizeof(*tx_beacon_cmd) + frame_size;
}

int iwlagn_send_beacon_cmd(struct iwl_priv *priv)
{
	struct iwl_frame *frame;
	unsigned int frame_size;
	int rc;
	struct iwl_host_cmd cmd = {
		.id = REPLY_TX_BEACON,
		.flags = CMD_SIZE_HUGE,
	};

	frame = iwl_get_free_frame(priv);
	if (!frame) {
		IWL_ERR(priv, "Could not obtain free frame buffer for beacon "
			  "command.\n");
		return -ENOMEM;
	}

	frame_size = iwl_hw_get_beacon_cmd(priv, frame);
	if (!frame_size) {
		IWL_ERR(priv, "Error configuring the beacon command\n");
		iwl_free_frame(priv, frame);
		return -EINVAL;
	}

	cmd.len = frame_size;
	cmd.data = &frame->u.cmd[0];

	rc = iwl_send_cmd_sync(priv, &cmd);

	iwl_free_frame(priv, frame);

	return rc;
}

static inline dma_addr_t iwl_tfd_tb_get_addr(struct iwl_tfd *tfd, u8 idx)
{
	struct iwl_tfd_tb *tb = &tfd->tbs[idx];

	dma_addr_t addr = get_unaligned_le32(&tb->lo);
	if (sizeof(dma_addr_t) > sizeof(u32))
		addr |=
		((dma_addr_t)(le16_to_cpu(tb->hi_n_len) & 0xF) << 16) << 16;

	return addr;
}

static inline u16 iwl_tfd_tb_get_len(struct iwl_tfd *tfd, u8 idx)
{
	struct iwl_tfd_tb *tb = &tfd->tbs[idx];

	return le16_to_cpu(tb->hi_n_len) >> 4;
}

static inline void iwl_tfd_set_tb(struct iwl_tfd *tfd, u8 idx,
				  dma_addr_t addr, u16 len)
{
	struct iwl_tfd_tb *tb = &tfd->tbs[idx];
	u16 hi_n_len = len << 4;

	put_unaligned_le32(addr, &tb->lo);
	if (sizeof(dma_addr_t) > sizeof(u32))
		hi_n_len |= ((addr >> 16) >> 16) & 0xF;

	tb->hi_n_len = cpu_to_le16(hi_n_len);

	tfd->num_tbs = idx + 1;
}

static inline u8 iwl_tfd_get_num_tbs(struct iwl_tfd *tfd)
{
	return tfd->num_tbs & 0x1f;
}

/**
 * iwl_hw_txq_free_tfd - Free all chunks referenced by TFD [txq->q.read_ptr]
 * @priv - driver private data
 * @txq - tx queue
 *
 * Does NOT advance any TFD circular buffer read/write indexes
 * Does NOT free the TFD itself (which is within circular buffer)
 */
void iwl_hw_txq_free_tfd(struct iwl_priv *priv, struct iwl_tx_queue *txq)
{
	struct iwl_tfd *tfd_tmp = (struct iwl_tfd *)txq->tfds;
	struct iwl_tfd *tfd;
	struct pci_dev *dev = priv->pci_dev;
	int index = txq->q.read_ptr;
	int i;
	int num_tbs;

	tfd = &tfd_tmp[index];

	/* Sanity check on number of chunks */
	num_tbs = iwl_tfd_get_num_tbs(tfd);

	if (num_tbs >= IWL_NUM_OF_TBS) {
		IWL_ERR(priv, "Too many chunks: %i\n", num_tbs);
		/* @todo issue fatal error, it is quite serious situation */
		return;
	}

	/* Unmap tx_cmd */
	if (num_tbs)
		pci_unmap_single(dev,
				dma_unmap_addr(&txq->meta[index], mapping),
				dma_unmap_len(&txq->meta[index], len),
				PCI_DMA_BIDIRECTIONAL);

	/* Unmap chunks, if any. */
	for (i = 1; i < num_tbs; i++)
		pci_unmap_single(dev, iwl_tfd_tb_get_addr(tfd, i),
				iwl_tfd_tb_get_len(tfd, i), PCI_DMA_TODEVICE);

	/* free SKB */
	if (txq->txb) {
		struct sk_buff *skb;

		skb = txq->txb[txq->q.read_ptr].skb;

		/* can be called from irqs-disabled context */
		if (skb) {
			dev_kfree_skb_any(skb);
			txq->txb[txq->q.read_ptr].skb = NULL;
		}
	}
}

int iwl_hw_txq_attach_buf_to_tfd(struct iwl_priv *priv,
				 struct iwl_tx_queue *txq,
				 dma_addr_t addr, u16 len,
				 u8 reset, u8 pad)
{
	struct iwl_queue *q;
	struct iwl_tfd *tfd, *tfd_tmp;
	u32 num_tbs;

	q = &txq->q;
	tfd_tmp = (struct iwl_tfd *)txq->tfds;
	tfd = &tfd_tmp[q->write_ptr];

	if (reset)
		memset(tfd, 0, sizeof(*tfd));

	num_tbs = iwl_tfd_get_num_tbs(tfd);

	/* Each TFD can point to a maximum 20 Tx buffers */
	if (num_tbs >= IWL_NUM_OF_TBS) {
		IWL_ERR(priv, "Error can not send more than %d chunks\n",
			  IWL_NUM_OF_TBS);
		return -EINVAL;
	}

	if (WARN_ON(addr & ~DMA_BIT_MASK(36)))
		return -EINVAL;

	if (unlikely(addr & ~IWL_TX_DMA_MASK))
		IWL_ERR(priv, "Unaligned address = %llx\n",
			  (unsigned long long)addr);

	iwl_tfd_set_tb(tfd, num_tbs, addr, len);

	return 0;
}

/*
 * Tell nic where to find circular buffer of Tx Frame Descriptors for
 * given Tx queue, and enable the DMA channel used for that queue.
 *
 * supports up to 16 Tx queues in DRAM, mapped to up to 8 Tx DMA
 * channels supported in hardware.
 */
int iwl_hw_tx_queue_init(struct iwl_priv *priv,
			 struct iwl_tx_queue *txq)
{
	int txq_id = txq->q.id;

	/* Circular buffer (TFD queue in DRAM) physical base address */
	iwl_write_direct32(priv, FH_MEM_CBBC_QUEUE(txq_id),
			     txq->q.dma_addr >> 8);

	return 0;
}

static void iwl_bg_beacon_update(struct work_struct *work)
{
	struct iwl_priv *priv =
		container_of(work, struct iwl_priv, beacon_update);
	struct sk_buff *beacon;

	mutex_lock(&priv->mutex);
	if (!priv->beacon_ctx) {
		IWL_ERR(priv, "updating beacon w/o beacon context!\n");
		goto out;
	}

	if (priv->beacon_ctx->vif->type != NL80211_IFTYPE_AP) {
		/*
		 * The ucode will send beacon notifications even in
		 * IBSS mode, but we don't want to process them. But
		 * we need to defer the type check to here due to
		 * requiring locking around the beacon_ctx access.
		 */
		goto out;
	}

	/* Pull updated AP beacon from mac80211. will fail if not in AP mode */
	beacon = ieee80211_beacon_get(priv->hw, priv->beacon_ctx->vif);
	if (!beacon) {
		IWL_ERR(priv, "update beacon failed -- keeping old\n");
		goto out;
	}

	/* new beacon skb is allocated every time; dispose previous.*/
	dev_kfree_skb(priv->beacon_skb);

	priv->beacon_skb = beacon;

	iwlagn_send_beacon_cmd(priv);
 out:
	mutex_unlock(&priv->mutex);
}

static void iwl_bg_bt_runtime_config(struct work_struct *work)
{
	struct iwl_priv *priv =
		container_of(work, struct iwl_priv, bt_runtime_config);

	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
		return;

	/* dont send host command if rf-kill is on */
	if (!iwl_is_ready_rf(priv))
		return;
	priv->cfg->ops->hcmd->send_bt_config(priv);
}

static void iwl_bg_bt_full_concurrency(struct work_struct *work)
{
	struct iwl_priv *priv =
		container_of(work, struct iwl_priv, bt_full_concurrency);
	struct iwl_rxon_context *ctx;

	mutex_lock(&priv->mutex);

	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
		goto out;

	/* dont send host command if rf-kill is on */
	if (!iwl_is_ready_rf(priv))
		goto out;

	IWL_DEBUG_INFO(priv, "BT coex in %s mode\n",
		       priv->bt_full_concurrent ?
		       "full concurrency" : "3-wire");

	/*
	 * LQ & RXON updated cmds must be sent before BT Config cmd
	 * to avoid 3-wire collisions
	 */
	for_each_context(priv, ctx) {
		if (priv->cfg->ops->hcmd->set_rxon_chain)
			priv->cfg->ops->hcmd->set_rxon_chain(priv, ctx);
		iwlcore_commit_rxon(priv, ctx);
	}

	priv->cfg->ops->hcmd->send_bt_config(priv);
out:
	mutex_unlock(&priv->mutex);
}

/**
 * iwl_bg_statistics_periodic - Timer callback to queue statistics
 *
 * This callback is provided in order to send a statistics request.
 *
 * This timer function is continually reset to execute within
 * REG_RECALIB_PERIOD seconds since the last STATISTICS_NOTIFICATION
 * was received.  We need to ensure we receive the statistics in order
 * to update the temperature used for calibrating the TXPOWER.
 */
static void iwl_bg_statistics_periodic(unsigned long data)
{
	struct iwl_priv *priv = (struct iwl_priv *)data;

	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
		return;

	/* dont send host command if rf-kill is on */
	if (!iwl_is_ready_rf(priv))
		return;

	iwl_send_statistics_request(priv, CMD_ASYNC, false);
}


static void iwl_print_cont_event_trace(struct iwl_priv *priv, u32 base,
					u32 start_idx, u32 num_events,
					u32 mode)
{
	u32 i;
	u32 ptr;        /* SRAM byte address of log data */
	u32 ev, time, data; /* event log data */
	unsigned long reg_flags;

	if (mode == 0)
		ptr = base + (4 * sizeof(u32)) + (start_idx * 2 * sizeof(u32));
	else
		ptr = base + (4 * sizeof(u32)) + (start_idx * 3 * sizeof(u32));

	/* Make sure device is powered up for SRAM reads */
	spin_lock_irqsave(&priv->reg_lock, reg_flags);
	if (iwl_grab_nic_access(priv)) {
		spin_unlock_irqrestore(&priv->reg_lock, reg_flags);
		return;
	}

	/* Set starting address; reads will auto-increment */
	iwl_write32(priv, HBUS_TARG_MEM_RADDR, ptr);
	rmb();

	/*
	 * "time" is actually "data" for mode 0 (no timestamp).
	 * place event id # at far right for easier visual parsing.
	 */
	for (i = 0; i < num_events; i++) {
		ev = iwl_read32(priv, HBUS_TARG_MEM_RDAT);
		time = iwl_read32(priv, HBUS_TARG_MEM_RDAT);
		if (mode == 0) {
			trace_iwlwifi_dev_ucode_cont_event(priv,
							0, time, ev);
		} else {
			data = iwl_read32(priv, HBUS_TARG_MEM_RDAT);
			trace_iwlwifi_dev_ucode_cont_event(priv,
						time, data, ev);
		}
	}
	/* Allow device to power down */
	iwl_release_nic_access(priv);
	spin_unlock_irqrestore(&priv->reg_lock, reg_flags);
}

static void iwl_continuous_event_trace(struct iwl_priv *priv)
{
	u32 capacity;   /* event log capacity in # entries */
	u32 base;       /* SRAM byte address of event log header */
	u32 mode;       /* 0 - no timestamp, 1 - timestamp recorded */
	u32 num_wraps;  /* # times uCode wrapped to top of log */
	u32 next_entry; /* index of next entry to be written by uCode */

	base = priv->device_pointers.error_event_table;
	if (priv->cfg->ops->lib->is_valid_rtc_data_addr(base)) {
		capacity = iwl_read_targ_mem(priv, base);
		num_wraps = iwl_read_targ_mem(priv, base + (2 * sizeof(u32)));
		mode = iwl_read_targ_mem(priv, base + (1 * sizeof(u32)));
		next_entry = iwl_read_targ_mem(priv, base + (3 * sizeof(u32)));
	} else
		return;

	if (num_wraps == priv->event_log.num_wraps) {
		iwl_print_cont_event_trace(priv,
				       base, priv->event_log.next_entry,
				       next_entry - priv->event_log.next_entry,
				       mode);
		priv->event_log.non_wraps_count++;
	} else {
		if ((num_wraps - priv->event_log.num_wraps) > 1)
			priv->event_log.wraps_more_count++;
		else
			priv->event_log.wraps_once_count++;
		trace_iwlwifi_dev_ucode_wrap_event(priv,
				num_wraps - priv->event_log.num_wraps,
				next_entry, priv->event_log.next_entry);
		if (next_entry < priv->event_log.next_entry) {
			iwl_print_cont_event_trace(priv, base,
			       priv->event_log.next_entry,
			       capacity - priv->event_log.next_entry,
			       mode);

			iwl_print_cont_event_trace(priv, base, 0,
				next_entry, mode);
		} else {
			iwl_print_cont_event_trace(priv, base,
			       next_entry, capacity - next_entry,
			       mode);

			iwl_print_cont_event_trace(priv, base, 0,
				next_entry, mode);
		}
	}
	priv->event_log.num_wraps = num_wraps;
	priv->event_log.next_entry = next_entry;
}

/**
 * iwl_bg_ucode_trace - Timer callback to log ucode event
 *
 * The timer is continually set to execute every
 * UCODE_TRACE_PERIOD milliseconds after the last timer expired
 * this function is to perform continuous uCode event logging operation
 * if enabled
 */
static void iwl_bg_ucode_trace(unsigned long data)
{
	struct iwl_priv *priv = (struct iwl_priv *)data;

	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
		return;

	if (priv->event_log.ucode_trace) {
		iwl_continuous_event_trace(priv);
		/* Reschedule the timer to occur in UCODE_TRACE_PERIOD */
		mod_timer(&priv->ucode_trace,
			 jiffies + msecs_to_jiffies(UCODE_TRACE_PERIOD));
	}
}

static void iwl_bg_tx_flush(struct work_struct *work)
{
	struct iwl_priv *priv =
		container_of(work, struct iwl_priv, tx_flush);

	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
		return;

	/* do nothing if rf-kill is on */
	if (!iwl_is_ready_rf(priv))
		return;

	if (priv->cfg->ops->lib->txfifo_flush) {
		IWL_DEBUG_INFO(priv, "device request: flush all tx frames\n");
		iwlagn_dev_txfifo_flush(priv, IWL_DROP_ALL);
	}
}

/**
 * iwl_rx_handle - Main entry function for receiving responses from uCode
 *
 * Uses the priv->rx_handlers callback function array to invoke
 * the appropriate handlers, including command responses,
 * frame-received notifications, and other notifications.
 */
static void iwl_rx_handle(struct iwl_priv *priv)
{
	struct iwl_rx_mem_buffer *rxb;
	struct iwl_rx_packet *pkt;
	struct iwl_rx_queue *rxq = &priv->rxq;
	u32 r, i;
	int reclaim;
	unsigned long flags;
	u8 fill_rx = 0;
	u32 count = 8;
	int total_empty;

	/* uCode's read index (stored in shared DRAM) indicates the last Rx
	 * buffer that the driver may process (last buffer filled by ucode). */
	r = le16_to_cpu(rxq->rb_stts->closed_rb_num) &  0x0FFF;
	i = rxq->read;

	/* Rx interrupt, but nothing sent from uCode */
	if (i == r)
		IWL_DEBUG_RX(priv, "r = %d, i = %d\n", r, i);

	/* calculate total frames need to be restock after handling RX */
	total_empty = r - rxq->write_actual;
	if (total_empty < 0)
		total_empty += RX_QUEUE_SIZE;

	if (total_empty > (RX_QUEUE_SIZE / 2))
		fill_rx = 1;

	while (i != r) {
		int len;

		rxb = rxq->queue[i];

		/* If an RXB doesn't have a Rx queue slot associated with it,
		 * then a bug has been introduced in the queue refilling
		 * routines -- catch it here */
		if (WARN_ON(rxb == NULL)) {
			i = (i + 1) & RX_QUEUE_MASK;
			continue;
		}

		rxq->queue[i] = NULL;

		pci_unmap_page(priv->pci_dev, rxb->page_dma,
			       PAGE_SIZE << priv->hw_params.rx_page_order,
			       PCI_DMA_FROMDEVICE);
		pkt = rxb_addr(rxb);

		len = le32_to_cpu(pkt->len_n_flags) & FH_RSCSR_FRAME_SIZE_MSK;
		len += sizeof(u32); /* account for status word */
		trace_iwlwifi_dev_rx(priv, pkt, len);

		/* Reclaim a command buffer only if this packet is a response
		 *   to a (driver-originated) command.
		 * If the packet (e.g. Rx frame) originated from uCode,
		 *   there is no command buffer to reclaim.
		 * Ucode should set SEQ_RX_FRAME bit if ucode-originated,
		 *   but apparently a few don't get set; catch them here. */
		reclaim = !(pkt->hdr.sequence & SEQ_RX_FRAME) &&
			(pkt->hdr.cmd != REPLY_RX_PHY_CMD) &&
			(pkt->hdr.cmd != REPLY_RX) &&
			(pkt->hdr.cmd != REPLY_RX_MPDU_CMD) &&
			(pkt->hdr.cmd != REPLY_COMPRESSED_BA) &&
			(pkt->hdr.cmd != STATISTICS_NOTIFICATION) &&
			(pkt->hdr.cmd != REPLY_TX);

		/*
		 * Do the notification wait before RX handlers so
		 * even if the RX handler consumes the RXB we have
		 * access to it in the notification wait entry.
		 */
		if (!list_empty(&priv->_agn.notif_waits)) {
			struct iwl_notification_wait *w;

			spin_lock(&priv->_agn.notif_wait_lock);
			list_for_each_entry(w, &priv->_agn.notif_waits, list) {
				if (w->cmd == pkt->hdr.cmd) {
					w->triggered = true;
					if (w->fn)
						w->fn(priv, pkt, w->fn_data);
				}
			}
			spin_unlock(&priv->_agn.notif_wait_lock);

			wake_up_all(&priv->_agn.notif_waitq);
		}

		/* Based on type of command response or notification,
		 *   handle those that need handling via function in
		 *   rx_handlers table.  See iwl_setup_rx_handlers() */
		if (priv->rx_handlers[pkt->hdr.cmd]) {
			IWL_DEBUG_RX(priv, "r = %d, i = %d, %s, 0x%02x\n", r,
				i, get_cmd_string(pkt->hdr.cmd), pkt->hdr.cmd);
			priv->isr_stats.rx_handlers[pkt->hdr.cmd]++;
			priv->rx_handlers[pkt->hdr.cmd] (priv, rxb);
		} else {
			/* No handling needed */
			IWL_DEBUG_RX(priv,
				"r %d i %d No handler needed for %s, 0x%02x\n",
				r, i, get_cmd_string(pkt->hdr.cmd),
				pkt->hdr.cmd);
		}

		/*
		 * XXX: After here, we should always check rxb->page
		 * against NULL before touching it or its virtual
		 * memory (pkt). Because some rx_handler might have
		 * already taken or freed the pages.
		 */

		if (reclaim) {
			/* Invoke any callbacks, transfer the buffer to caller,
			 * and fire off the (possibly) blocking iwl_send_cmd()
			 * as we reclaim the driver command queue */
			if (rxb->page)
				iwl_tx_cmd_complete(priv, rxb);
			else
				IWL_WARN(priv, "Claim null rxb?\n");
		}

		/* Reuse the page if possible. For notification packets and
		 * SKBs that fail to Rx correctly, add them back into the
		 * rx_free list for reuse later. */
		spin_lock_irqsave(&rxq->lock, flags);
		if (rxb->page != NULL) {
			rxb->page_dma = pci_map_page(priv->pci_dev, rxb->page,
				0, PAGE_SIZE << priv->hw_params.rx_page_order,
				PCI_DMA_FROMDEVICE);
			list_add_tail(&rxb->list, &rxq->rx_free);
			rxq->free_count++;
		} else
			list_add_tail(&rxb->list, &rxq->rx_used);

		spin_unlock_irqrestore(&rxq->lock, flags);

		i = (i + 1) & RX_QUEUE_MASK;
		/* If there are a lot of unused frames,
		 * restock the Rx queue so ucode wont assert. */
		if (fill_rx) {
			count++;
			if (count >= 8) {
				rxq->read = i;
				iwlagn_rx_replenish_now(priv);
				count = 0;
			}
		}
	}

	/* Backtrack one entry */
	rxq->read = i;
	if (fill_rx)
		iwlagn_rx_replenish_now(priv);
	else
		iwlagn_rx_queue_restock(priv);
}

/* tasklet for iwlagn interrupt */
static void iwl_irq_tasklet(struct iwl_priv *priv)
{
	u32 inta = 0;
	u32 handled = 0;
	unsigned long flags;
	u32 i;
#ifdef CONFIG_IWLWIFI_DEBUG
	u32 inta_mask;
#endif

	spin_lock_irqsave(&priv->lock, flags);

	/* Ack/clear/reset pending uCode interrupts.
	 * Note:  Some bits in CSR_INT are "OR" of bits in CSR_FH_INT_STATUS,
	 */
	/* There is a hardware bug in the interrupt mask function that some
	 * interrupts (i.e. CSR_INT_BIT_SCD) can still be generated even if
	 * they are disabled in the CSR_INT_MASK register. Furthermore the
	 * ICT interrupt handling mechanism has another bug that might cause
	 * these unmasked interrupts fail to be detected. We workaround the
	 * hardware bugs here by ACKing all the possible interrupts so that
	 * interrupt coalescing can still be achieved.
	 */
	iwl_write32(priv, CSR_INT, priv->_agn.inta | ~priv->inta_mask);

	inta = priv->_agn.inta;

#ifdef CONFIG_IWLWIFI_DEBUG
	if (iwl_get_debug_level(priv) & IWL_DL_ISR) {
		/* just for debug */
		inta_mask = iwl_read32(priv, CSR_INT_MASK);
		IWL_DEBUG_ISR(priv, "inta 0x%08x, enabled 0x%08x\n ",
				inta, inta_mask);
	}
#endif

	spin_unlock_irqrestore(&priv->lock, flags);

	/* saved interrupt in inta variable now we can reset priv->_agn.inta */
	priv->_agn.inta = 0;

	/* Now service all interrupt bits discovered above. */
	if (inta & CSR_INT_BIT_HW_ERR) {
		IWL_ERR(priv, "Hardware error detected.  Restarting.\n");

		/* Tell the device to stop sending interrupts */
		iwl_disable_interrupts(priv);

		priv->isr_stats.hw++;
		iwl_irq_handle_error(priv);

		handled |= CSR_INT_BIT_HW_ERR;

		return;
	}

#ifdef CONFIG_IWLWIFI_DEBUG
	if (iwl_get_debug_level(priv) & (IWL_DL_ISR)) {
		/* NIC fires this, but we don't use it, redundant with WAKEUP */
		if (inta & CSR_INT_BIT_SCD) {
			IWL_DEBUG_ISR(priv, "Scheduler finished to transmit "
				      "the frame/frames.\n");
			priv->isr_stats.sch++;
		}

		/* Alive notification via Rx interrupt will do the real work */
		if (inta & CSR_INT_BIT_ALIVE) {
			IWL_DEBUG_ISR(priv, "Alive interrupt\n");
			priv->isr_stats.alive++;
		}
	}
#endif
	/* Safely ignore these bits for debug checks below */
	inta &= ~(CSR_INT_BIT_SCD | CSR_INT_BIT_ALIVE);

	/* HW RF KILL switch toggled */
	if (inta & CSR_INT_BIT_RF_KILL) {
		int hw_rf_kill = 0;
		if (!(iwl_read32(priv, CSR_GP_CNTRL) &
				CSR_GP_CNTRL_REG_FLAG_HW_RF_KILL_SW))
			hw_rf_kill = 1;

		IWL_WARN(priv, "RF_KILL bit toggled to %s.\n",
				hw_rf_kill ? "disable radio" : "enable radio");

		priv->isr_stats.rfkill++;

		/* driver only loads ucode once setting the interface up.
		 * the driver allows loading the ucode even if the radio
		 * is killed. Hence update the killswitch state here. The
		 * rfkill handler will care about restarting if needed.
		 */
		if (!test_bit(STATUS_ALIVE, &priv->status)) {
			if (hw_rf_kill)
				set_bit(STATUS_RF_KILL_HW, &priv->status);
			else
				clear_bit(STATUS_RF_KILL_HW, &priv->status);
			wiphy_rfkill_set_hw_state(priv->hw->wiphy, hw_rf_kill);
		}

		handled |= CSR_INT_BIT_RF_KILL;
	}

	/* Chip got too hot and stopped itself */
	if (inta & CSR_INT_BIT_CT_KILL) {
		IWL_ERR(priv, "Microcode CT kill error detected.\n");
		priv->isr_stats.ctkill++;
		handled |= CSR_INT_BIT_CT_KILL;
	}

	/* Error detected by uCode */
	if (inta & CSR_INT_BIT_SW_ERR) {
		IWL_ERR(priv, "Microcode SW error detected. "
			" Restarting 0x%X.\n", inta);
		priv->isr_stats.sw++;
		iwl_irq_handle_error(priv);
		handled |= CSR_INT_BIT_SW_ERR;
	}

	/* uCode wakes up after power-down sleep */
	if (inta & CSR_INT_BIT_WAKEUP) {
		IWL_DEBUG_ISR(priv, "Wakeup interrupt\n");
		iwl_rx_queue_update_write_ptr(priv, &priv->rxq);
		for (i = 0; i < priv->hw_params.max_txq_num; i++)
			iwl_txq_update_write_ptr(priv, &priv->txq[i]);

		priv->isr_stats.wakeup++;

		handled |= CSR_INT_BIT_WAKEUP;
	}

	/* All uCode command responses, including Tx command responses,
	 * Rx "responses" (frame-received notification), and other
	 * notifications from uCode come through here*/
	if (inta & (CSR_INT_BIT_FH_RX | CSR_INT_BIT_SW_RX |
			CSR_INT_BIT_RX_PERIODIC)) {
		IWL_DEBUG_ISR(priv, "Rx interrupt\n");
		if (inta & (CSR_INT_BIT_FH_RX | CSR_INT_BIT_SW_RX)) {
			handled |= (CSR_INT_BIT_FH_RX | CSR_INT_BIT_SW_RX);
			iwl_write32(priv, CSR_FH_INT_STATUS,
					CSR_FH_INT_RX_MASK);
		}
		if (inta & CSR_INT_BIT_RX_PERIODIC) {
			handled |= CSR_INT_BIT_RX_PERIODIC;
			iwl_write32(priv, CSR_INT, CSR_INT_BIT_RX_PERIODIC);
		}
		/* Sending RX interrupt require many steps to be done in the
		 * the device:
		 * 1- write interrupt to current index in ICT table.
		 * 2- dma RX frame.
		 * 3- update RX shared data to indicate last write index.