iwlwifi: add comments to iwl*-base.c

Add comments to iwlXXXX-base.c

Signed-off-by: Cahill, Ben M <ben.m.cahill@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 179 insertions, 33 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl4965-base.c b/drivers/net/wireless/iwlwifi/iwl4965-base.c
index 66aa938e316..43ce645e4a6 100644
--- a/drivers/net/wireless/iwlwifi/iwl4965-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl4965-base.c
@@ -63,13 +63,13 @@ static int iwl4965_tx_queue_update_write_ptr(struct iwl4965_priv *priv,
  ******************************************************************************/
 
 /* module parameters */
-static int iwl4965_param_disable_hw_scan;
-static int iwl4965_param_debug;
+static int iwl4965_param_disable_hw_scan; /* def: 0 = use 4965's h/w scan */
+static int iwl4965_param_debug;    /* def: 0 = minimal debug log messages */
 static int iwl4965_param_disable;  /* def: enable radio */
 static int iwl4965_param_antenna;  /* def: 0 = both antennas (use diversity) */
 int iwl4965_param_hwcrypto;        /* def: using software encryption */
-static int iwl4965_param_qos_enable = 1;
-int iwl4965_param_queues_num = IWL_MAX_NUM_QUEUES;
+static int iwl4965_param_qos_enable = 1; /* def: 1 = use quality of service */
+int iwl4965_param_queues_num = IWL_MAX_NUM_QUEUES; /* def: 16 Tx queues */
 
 /*
  * module name, copyright, version, etc.
@@ -183,17 +183,24 @@ static void iwl4965_print_hex_dump(int level, void *p, u32 len)
  *
  * Theory of operation
  *
- * A queue is a circular buffers with 'Read' and 'Write' pointers.
- * 2 empty entries always kept in the buffer to protect from overflow.
+ * A Tx or Rx queue resides in host DRAM, and is comprised of a circular buffer
+ * of buffer descriptors, each of which points to one or more data buffers for
+ * the device to read from or fill.  Driver and device exchange status of each
+ * queue via "read" and "write" pointers.  Driver keeps minimum of 2 empty
+ * entries in each circular buffer, to protect against confusing empty and full
+ * queue states.
+ *
+ * The device reads or writes the data in the queues via the device's several
+ * DMA/FIFO channels.  Each queue is mapped to a single DMA channel.
  *
  * For Tx queue, there are low mark and high mark limits. If, after queuing
  * the packet for Tx, free space become < low mark, Tx queue stopped. When
  * reclaiming packets (on 'tx done IRQ), if free space become > high mark,
  * Tx queue resumed.
  *
- * The IWL operates with six queues, one receive queue in the device's
- * sram, one transmit queue for sending commands to the device firmware,
- * and four transmit queues for data.
+ * The 4965 operates with up to 17 queues:  One receive queue, one transmit
+ * queue (#4) for sending commands to the device firmware, and 15 other
+ * Tx queues that may be mapped to prioritized Tx DMA/FIFO channels.
  ***************************************************/
 
 static int iwl4965_queue_space(const struct iwl4965_queue *q)
@@ -212,13 +219,21 @@ static int iwl4965_queue_space(const struct iwl4965_queue *q)
 	return s;
 }
 
-/* XXX: n_bd must be power-of-two size */
+/**
+ * iwl4965_queue_inc_wrap - increment queue index, wrap back to beginning
+ * @index -- current index
+ * @n_bd -- total number of entries in queue (must be power of 2)
+ */
 static inline int iwl4965_queue_inc_wrap(int index, int n_bd)
 {
 	return ++index & (n_bd - 1);
 }
 
-/* XXX: n_bd must be power-of-two size */
+/**
+ * iwl4965_queue_dec_wrap - decrement queue index, wrap back to end
+ * @index -- current index
+ * @n_bd -- total number of entries in queue (must be power of 2)
+ */
 static inline int iwl4965_queue_dec_wrap(int index, int n_bd)
 {
 	return --index & (n_bd - 1);
@@ -233,12 +248,17 @@ static inline int x2_queue_used(const struct iwl4965_queue *q, int i)
 
 static inline u8 get_cmd_index(struct iwl4965_queue *q, u32 index, int is_huge)
 {
+	/* This is for scan command, the big buffer at end of command array */
 	if (is_huge)
-		return q->n_window;
+		return q->n_window;	/* must be power of 2 */
 
+	/* Otherwise, use normal size buffers */
 	return index & (q->n_window - 1);
 }
 
+/**
+ * iwl4965_queue_init - Initialize queue's high/low-water and read/write indexes
+ */
 static int iwl4965_queue_init(struct iwl4965_priv *priv, struct iwl4965_queue *q,
 			  int count, int slots_num, u32 id)
 {
@@ -267,11 +287,16 @@ static int iwl4965_queue_init(struct iwl4965_priv *priv, struct iwl4965_queue *q
 	return 0;
 }
 
+/**
+ * iwl4965_tx_queue_alloc - Alloc driver data and TFD CB for one Tx/cmd queue
+ */
 static int iwl4965_tx_queue_alloc(struct iwl4965_priv *priv,
 			      struct iwl4965_tx_queue *txq, u32 id)
 {
 	struct pci_dev *dev = priv->pci_dev;
 
+	/* Driver private data, only for Tx (not command) queues,
+	 * not shared with device. */
 	if (id != IWL_CMD_QUEUE_NUM) {
 		txq->txb = kmalloc(sizeof(txq->txb[0]) *
 				   TFD_QUEUE_SIZE_MAX, GFP_KERNEL);
@@ -283,6 +308,8 @@ static int iwl4965_tx_queue_alloc(struct iwl4965_priv *priv,
 	} else
 		txq->txb = NULL;
 
+	/* Circular buffer of transmit frame descriptors (TFDs),
+	 * shared with device */
 	txq->bd = pci_alloc_consistent(dev,
 			sizeof(txq->bd[0]) * TFD_QUEUE_SIZE_MAX,
 			&txq->q.dma_addr);
@@ -320,7 +347,7 @@ int iwl4965_tx_queue_init(struct iwl4965_priv *priv,
 	 * For the command queue (#4), allocate command space + one big
 	 * command for scan, since scan command is very huge; the system will
 	 * not have two scans at the same time, so only one is needed.
-	 * For normal Tx queues (all other queues), no super-size command
+	 * For data Tx queues (all other queues), no super-size command
 	 * space is needed.
 	 */
 	len = sizeof(struct iwl4965_cmd) * slots_num;
@@ -357,8 +384,8 @@ int iwl4965_tx_queue_init(struct iwl4965_priv *priv,
  * @txq: Transmit queue to deallocate.
  *
  * Empty queue by removing and destroying all BD's.
- * Free all buffers.  txq itself is not freed.
- *
+ * Free all buffers.
+ * 0-fill, but do not free "txq" descriptor structure.
  */
 void iwl4965_tx_queue_free(struct iwl4965_priv *priv, struct iwl4965_tx_queue *txq)
 {
@@ -378,19 +405,21 @@ void iwl4965_tx_queue_free(struct iwl4965_priv *priv, struct iwl4965_tx_queue *t
 	if (q->id == IWL_CMD_QUEUE_NUM)
 		len += IWL_MAX_SCAN_SIZE;
 
+	/* De-alloc array of command/tx buffers */
 	pci_free_consistent(dev, len, txq->cmd, txq->dma_addr_cmd);
 
-	/* free buffers belonging to queue itself */
+	/* De-alloc circular buffer of TFDs */
 	if (txq->q.n_bd)
 		pci_free_consistent(dev, sizeof(struct iwl4965_tfd_frame) *
 				    txq->q.n_bd, txq->bd, txq->q.dma_addr);
 
+	/* De-alloc array of per-TFD driver data */
 	if (txq->txb) {
 		kfree(txq->txb);
 		txq->txb = NULL;
 	}
 
-	/* 0 fill whole structure */
+	/* 0-fill queue descriptor structure */
 	memset(txq, 0, sizeof(*txq));
 }
 
@@ -404,6 +433,11 @@ const u8 iwl4965_broadcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
 /**************************************************************/
 
 #if 0 /* temporary disable till we add real remove station */
+/**
+ * iwl4965_remove_station - Remove driver's knowledge of station.
+ *
+ * NOTE:  This does not remove station from device's station table.
+ */
 static u8 iwl4965_remove_station(struct iwl4965_priv *priv, const u8 *addr, int is_ap)
 {
 	int index = IWL_INVALID_STATION;
@@ -441,6 +475,11 @@ out:
 }
 #endif
 
+/**
+ * iwl4965_clear_stations_table - Clear the driver's station table
+ *
+ * NOTE:  This does not clear or otherwise alter the device's station table.
+ */
 static void iwl4965_clear_stations_table(struct iwl4965_priv *priv)
 {
 	unsigned long flags;
@@ -453,6 +492,9 @@ static void iwl4965_clear_stations_table(struct iwl4965_priv *priv)
 	spin_unlock_irqrestore(&priv->sta_lock, flags);
 }
 
+/**
+ * iwl4965_add_station_flags - Add station to tables in driver and device
+ */
 u8 iwl4965_add_station_flags(struct iwl4965_priv *priv, const u8 *addr, int is_ap, u8 flags)
 {
 	int i;
@@ -499,6 +541,7 @@ u8 iwl4965_add_station_flags(struct iwl4965_priv *priv, const u8 *addr, int is_a
 	station->used = 1;
 	priv->num_stations++;
 
+	/* Set up the REPLY_ADD_STA command to send to device */
 	memset(&station->sta, 0, sizeof(struct iwl4965_addsta_cmd));
 	memcpy(station->sta.sta.addr, addr, ETH_ALEN);
 	station->sta.mode = 0;
@@ -513,6 +556,8 @@ u8 iwl4965_add_station_flags(struct iwl4965_priv *priv, const u8 *addr, int is_a
 #endif /*CONFIG_IWL4965_HT*/
 
 	spin_unlock_irqrestore(&priv->sta_lock, flags_spin);
+
+	/* Add station to device's station table */
 	iwl4965_send_add_station(priv, &station->sta, flags);
 	return index;
 
@@ -682,7 +727,11 @@ static int iwl4965_enqueue_hcmd(struct iwl4965_priv *priv, struct iwl4965_host_c
 		     fix_size, q->write_ptr, idx, IWL_CMD_QUEUE_NUM);
 
 	txq->need_update = 1;
+
+	/* Set up entry in queue's byte count circular buffer */
 	ret = iwl4965_tx_queue_update_wr_ptr(priv, txq, 0);
+
+	/* Increment and update queue's write index */
 	q->write_ptr = iwl4965_queue_inc_wrap(q->write_ptr, q->n_bd);
 	iwl4965_tx_queue_update_write_ptr(priv, txq);
 
@@ -848,7 +897,10 @@ static int iwl4965_rxon_add_station(struct iwl4965_priv *priv,
 {
 	u8 sta_id;
 
+	/* Add station to device's station table */
 	sta_id = iwl4965_add_station_flags(priv, addr, is_ap, 0);
+
+	/* Set up default rate scaling table in device's station table */
 	iwl4965_add_station(priv, addr, is_ap);
 
 	return sta_id;
@@ -1574,7 +1626,7 @@ static void get_eeprom_mac(struct iwl4965_priv *priv, u8 *mac)
 /**
  * iwl4965_eeprom_init - read EEPROM contents
  *
- * Load the EEPROM from adapter into priv->eeprom
+ * Load the EEPROM contents from adapter into priv->eeprom
  *
  * NOTE:  This routine uses the non-debug IO access functions.
  */
@@ -1599,6 +1651,7 @@ int iwl4965_eeprom_init(struct iwl4965_priv *priv)
 		return -ENOENT;
 	}
 
+	/* Make sure driver (instead of uCode) is allowed to read EEPROM */
 	rc = iwl4965_eeprom_acquire_semaphore(priv);
 	if (rc < 0) {
 		IWL_ERROR("Failed to acquire EEPROM semaphore.\n");
@@ -2739,6 +2792,11 @@ static void iwl4965_build_tx_cmd_basic(struct iwl4965_priv *priv,
 	cmd->cmd.tx.next_frame_len = 0;
 }
 
+/**
+ * iwl4965_get_sta_id - Find station's index within station table
+ *
+ * If new IBSS station, create new entry in station table
+ */
 static int iwl4965_get_sta_id(struct iwl4965_priv *priv,
 				struct ieee80211_hdr *hdr)
 {
@@ -2746,16 +2804,15 @@ static int iwl4965_get_sta_id(struct iwl4965_priv *priv,
 	u16 fc = le16_to_cpu(hdr->frame_control);
 	DECLARE_MAC_BUF(mac);
 
-	/* If this frame is broadcast or not data then use the broadcast
-	 * station id */
+	/* If this frame is broadcast or management, use broadcast station id */
 	if (((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA) ||
 	    is_multicast_ether_addr(hdr->addr1))
 		return priv->hw_setting.bcast_sta_id;
 
 	switch (priv->iw_mode) {
 
-	/* If this frame is part of a BSS network (we're a station), then
-	 * we use the AP's station id */
+	/* If we are a client station in a BSS network, use the special
+	 * AP station entry (that's the only station we communicate with) */
 	case IEEE80211_IF_TYPE_STA:
 		return IWL_AP_ID;
 
@@ -2766,13 +2823,14 @@ static int iwl4965_get_sta_id(struct iwl4965_priv *priv,
 			return sta_id;
 		return priv->hw_setting.bcast_sta_id;
 
-	/* If this frame is part of a IBSS network, then we use the
-	 * target specific station id */
+	/* If this frame is going out to an IBSS network, find the station,
+	 * or create a new station table entry */
 	case IEEE80211_IF_TYPE_IBSS:
 		sta_id = iwl4965_hw_find_station(priv, hdr->addr1);
 		if (sta_id != IWL_INVALID_STATION)
 			return sta_id;
 
+		/* Create new station table entry */
 		sta_id = iwl4965_add_station_flags(priv, hdr->addr1, 0, CMD_ASYNC);
 
 		if (sta_id != IWL_INVALID_STATION)
@@ -2854,6 +2912,8 @@ static int iwl4965_tx_skb(struct iwl4965_priv *priv,
 	spin_unlock_irqrestore(&priv->lock, flags);
 
 	hdr_len = ieee80211_get_hdrlen(fc);
+
+	/* Find (or create) index into station table for destination station */
 	sta_id = iwl4965_get_sta_id(priv, hdr);
 	if (sta_id == IWL_INVALID_STATION) {
 		DECLARE_MAC_BUF(mac);
@@ -2882,30 +2942,52 @@ static int iwl4965_tx_skb(struct iwl4965_priv *priv,
 #endif /* CONFIG_IWL4965_HT_AGG */
 #endif /* CONFIG_IWL4965_HT */
 	}
+
+	/* Descriptor for chosen Tx queue */
 	txq = &priv->txq[txq_id];
 	q = &txq->q;
 
 	spin_lock_irqsave(&priv->lock, flags);
 
+	/* Set up first empty TFD within this queue's circular TFD buffer */
 	tfd = &txq->bd[q->write_ptr];
 	memset(tfd, 0, sizeof(*tfd));
 	control_flags = (u32 *) tfd;
 	idx = get_cmd_index(q, q->write_ptr, 0);
 
+	/* Set up driver data for this TFD */
 	memset(&(txq->txb[q->write_ptr]), 0, sizeof(struct iwl4965_tx_info));
 	txq->txb[q->write_ptr].skb[0] = skb;
 	memcpy(&(txq->txb[q->write_ptr].status.control),
 	       ctl, sizeof(struct ieee80211_tx_control));
+
+	/* Set up first empty entry in queue's array of Tx/cmd buffers */
 	out_cmd = &txq->cmd[idx];
 	memset(&out_cmd->hdr, 0, sizeof(out_cmd->hdr));
 	memset(&out_cmd->cmd.tx, 0, sizeof(out_cmd->cmd.tx));
+
+	/*
+	 * Set up the Tx-command (not MAC!) header.
+	 * Store the chosen Tx queue and TFD index within the sequence field;
+	 * after Tx, uCode's Tx response will return this value so driver can
+	 * locate the frame within the tx queue and do post-tx processing.
+	 */
 	out_cmd->hdr.cmd = REPLY_TX;
 	out_cmd->hdr.sequence = cpu_to_le16((u16)(QUEUE_TO_SEQ(txq_id) |
 				INDEX_TO_SEQ(q->write_ptr)));
-	/* copy frags header */
+
+	/* Copy MAC header from skb into command buffer */
 	memcpy(out_cmd->cmd.tx.hdr, hdr, hdr_len);
 
-	/* hdr = (struct ieee80211_hdr *)out_cmd->cmd.tx.hdr; */
+	/*
+	 * Use the first empty entry in this queue's command buffer array
+	 * to contain the Tx command and MAC header concatenated together
+	 * (payload data will be in another buffer).
+	 * Size of this varies, due to varying MAC header length.
+	 * If end is not dword aligned, we'll have 2 extra bytes at the end
+	 * of the MAC header (device reads on dword boundaries).
+	 * We'll tell device about this padding later.
+	 */
 	len = priv->hw_setting.tx_cmd_len +
 		sizeof(struct iwl4965_cmd_header) + hdr_len;
 
@@ -2917,15 +2999,20 @@ static int iwl4965_tx_skb(struct iwl4965_priv *priv,
 	else
 		len_org = 0;
 
+	/* Physical address of this Tx command's header (not MAC header!),
+	 * within command buffer array. */
 	txcmd_phys = txq->dma_addr_cmd + sizeof(struct iwl4965_cmd) * idx +
 		     offsetof(struct iwl4965_cmd, hdr);
 
+	/* Add buffer containing Tx command and MAC(!) header to TFD's
+	 * first entry */
 	iwl4965_hw_txq_attach_buf_to_tfd(priv, tfd, txcmd_phys, len);
 
 	if (!(ctl->flags & IEEE80211_TXCTL_DO_NOT_ENCRYPT))
 		iwl4965_build_tx_cmd_hwcrypto(priv, ctl, out_cmd, skb, 0);
 
-	/* 802.11 null functions have no payload... */
+	/* Set up TFD's 2nd entry to point directly to remainder of skb,
+	 * if any (802.11 null frames have no payload). */
 	len = skb->len - hdr_len;
 	if (len) {
 		phys_addr = pci_map_single(priv->pci_dev, skb->data + hdr_len,
@@ -2933,9 +3020,11 @@ static int iwl4965_tx_skb(struct iwl4965_priv *priv,
 		iwl4965_hw_txq_attach_buf_to_tfd(priv, tfd, phys_addr, len);
 	}
 
+	/* Tell 4965 about any 2-byte padding after MAC header */
 	if (len_org)
 		out_cmd->cmd.tx.tx_flags |= TX_CMD_FLG_MH_PAD_MSK;
 
+	/* Total # bytes to be transmitted */
 	len = (u16)skb->len;
 	out_cmd->cmd.tx.len = cpu_to_le16(len);
 
@@ -2965,8 +3054,10 @@ static int iwl4965_tx_skb(struct iwl4965_priv *priv,
 	iwl4965_print_hex_dump(IWL_DL_TX, (u8 *)out_cmd->cmd.tx.hdr,
 			   ieee80211_get_hdrlen(fc));
 
+	/* Set up entry for this TFD in Tx byte-count array */
 	iwl4965_tx_queue_update_wr_ptr(priv, txq, len);
 
+	/* Tell device the write index *just past* this latest filled TFD */
 	q->write_ptr = iwl4965_queue_inc_wrap(q->write_ptr, q->n_bd);
 	rc = iwl4965_tx_queue_update_write_ptr(priv, txq);
 	spin_unlock_irqrestore(&priv->lock, flags);
@@ -3443,11 +3534,11 @@ static void iwl4965_txstatus_to_ieee(struct iwl4965_priv *priv,
 }
 
 /**
- * iwl4965_tx_queue_reclaim - Reclaim Tx queue entries no more used by NIC.
+ * iwl4965_tx_queue_reclaim - Reclaim Tx queue entries already Tx'd
  *
- * When FW advances 'R' index, all entries between old and
- * new 'R' index need to be reclaimed. As result, some free space
- * forms. If there is enough free space (> low mark), wake Tx queue.
+ * When FW advances 'R' index, all entries between old and new 'R' index
+ * need to be reclaimed. As result, some free space forms.  If there is
+ * enough free space (> low mark), wake the stack that feeds us.
  */
 int iwl4965_tx_queue_reclaim(struct iwl4965_priv *priv, int txq_id, int index)
 {
@@ -3528,6 +3619,10 @@ static inline u32 iwl4965_get_scd_ssn(struct iwl4965_tx_resp *tx_resp)
 	return le32_to_cpu(*scd_ssn) & MAX_SN;
 
 }
+
+/**
+ * iwl4965_tx_status_reply_tx - Handle Tx rspnse for frames in aggregation queue
+ */
 static int iwl4965_tx_status_reply_tx(struct iwl4965_priv *priv,
 				      struct iwl4965_ht_agg *agg,
 				      struct iwl4965_tx_resp *tx_resp,
@@ -3542,14 +3637,16 @@ static int iwl4965_tx_status_reply_tx(struct iwl4965_priv *priv,
 	u16 seq;
 
 	if (agg->wait_for_ba)
-		IWL_DEBUG_TX_REPLY("got tx repsons w/o back\n");
+		IWL_DEBUG_TX_REPLY("got tx response w/o block-ack\n");
 
 	agg->frame_count = tx_resp->frame_count;
 	agg->start_idx = start_idx;
 	agg->rate_n_flags = le32_to_cpu(tx_resp->rate_n_flags);
 	agg->bitmap0 = agg->bitmap1 = 0;
 
+	/* # frames attempted by Tx command */
 	if (agg->frame_count == 1) {
+		/* Only one frame was attempted; no block-ack will arrive */
 		struct iwl4965_tx_queue *txq ;
 		status = le32_to_cpu(frame_status[0]);
 
@@ -3578,9 +3675,11 @@ static int iwl4965_tx_status_reply_tx(struct iwl4965_priv *priv,
 
 		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 = le32_to_cpu(frame_status[i]);
@@ -3644,6 +3743,9 @@ static int iwl4965_tx_status_reply_tx(struct iwl4965_priv *priv,
 #endif
 #endif
 
+/**
+ * iwl4965_rx_reply_tx - Handle standard (non-aggregation) Tx response
+ */
 static void iwl4965_rx_reply_tx(struct iwl4965_priv *priv,
 			    struct iwl4965_rx_mem_buffer *rxb)
 {
@@ -4265,6 +4367,7 @@ int iwl4965_rx_queue_update_write_ptr(struct iwl4965_priv *priv, struct iwl4965_
 	if (q->need_update == 0)
 		goto exit_unlock;
 
+	/* If power-saving is in use, make sure device is awake */
 	if (test_bit(STATUS_POWER_PMI, &priv->status)) {
 		reg = iwl4965_read32(priv, CSR_UCODE_DRV_GP1);
 
@@ -4278,10 +4381,14 @@ int iwl4965_rx_queue_update_write_ptr(struct iwl4965_priv *priv, struct iwl4965_
 		if (rc)
 			goto exit_unlock;
 
+		/* Device expects a multiple of 8 */
 		iwl4965_write_direct32(priv, FH_RSCSR_CHNL0_WPTR,
 				     q->write & ~0x7);
 		iwl4965_release_nic_access(priv);
+
+	/* Else device is assumed to be awake */
 	} else
+		/* Device expects a multiple of 8 */
 		iwl4965_write32(priv, FH_RSCSR_CHNL0_WPTR, q->write & ~0x7);
 
 
@@ -4324,9 +4431,12 @@ static int iwl4965_rx_queue_restock(struct iwl4965_priv *priv)
 	spin_lock_irqsave(&rxq->lock, flags);
 	write = rxq->write & ~0x7;
 	while ((iwl4965_rx_queue_space(rxq) > 0) && (rxq->free_count)) {
+		/* Get next free Rx buffer, remove from free list */
 		element = rxq->rx_free.next;
 		rxb = list_entry(element, struct iwl4965_rx_mem_buffer, list);
 		list_del(element);
+
+		/* Point to Rx buffer via next RBD in circular buffer */
 		rxq->bd[rxq->write] = iwl4965_dma_addr2rbd_ptr(priv, rxb->dma_addr);
 		rxq->queue[rxq->write] = rxb;
 		rxq->write = (rxq->write + 1) & RX_QUEUE_MASK;
@@ -4339,7 +4449,8 @@ static int iwl4965_rx_queue_restock(struct iwl4965_priv *priv)
 		queue_work(priv->workqueue, &priv->rx_replenish);
 
 
-	/* If we've added more space for the firmware to place data, tell it */
+	/* If we've added more space for the firmware to place data, tell it.
+	 * Increment device's write pointer in multiples of 8. */
 	if ((write != (rxq->write & ~0x7))
 	    || (abs(rxq->write - rxq->read) > 7)) {
 		spin_lock_irqsave(&rxq->lock, flags);
@@ -4372,6 +4483,8 @@ void iwl4965_rx_replenish(void *data)
 	while (!list_empty(&rxq->rx_used)) {
 		element = rxq->rx_used.next;
 		rxb = list_entry(element, struct iwl4965_rx_mem_buffer, list);
+
+		/* Alloc a new receive buffer */
 		rxb->skb =
 		    alloc_skb(IWL_RX_BUF_SIZE, __GFP_NOWARN | GFP_ATOMIC);
 		if (!rxb->skb) {
@@ -4385,6 +4498,8 @@ void iwl4965_rx_replenish(void *data)
 		}
 		priv->alloc_rxb_skb++;
 		list_del(element);
+
+		/* Get physical address of RB/SKB */
 		rxb->dma_addr =
 		    pci_map_single(priv->pci_dev, rxb->skb->data,
 				   IWL_RX_BUF_SIZE, PCI_DMA_FROMDEVICE);
@@ -4429,12 +4544,16 @@ int iwl4965_rx_queue_alloc(struct iwl4965_priv *priv)
 	spin_lock_init(&rxq->lock);
 	INIT_LIST_HEAD(&rxq->rx_free);
 	INIT_LIST_HEAD(&rxq->rx_used);
+
+	/* Alloc the circular buffer of Read Buffer Descriptors (RBDs) */
 	rxq->bd = pci_alloc_consistent(dev, 4 * RX_QUEUE_SIZE, &rxq->dma_addr);
 	if (!rxq->bd)
 		return -ENOMEM;
+
 	/* Fill the rx_used queue with _all_ of the Rx buffers */
 	for (i = 0; i < RX_FREE_BUFFERS + RX_QUEUE_SIZE; i++)
 		list_add_tail(&rxq->pool[i].list, &rxq->rx_used);
+
 	/* 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;
@@ -4566,6 +4685,8 @@ static void iwl4965_rx_handle(struct iwl4965_priv *priv)
 	int reclaim;
 	unsigned long flags;
 
+	/* uCode's read index (stored in shared DRAM) indicates the last Rx
+	 * buffer that the driver may process (last buffer filled by ucode). */
 	r = iwl4965_hw_get_rx_read(priv);
 	i = rxq->read;
 
@@ -4649,6 +4770,9 @@ static void iwl4965_rx_handle(struct iwl4965_priv *priv)
 	iwl4965_rx_queue_restock(priv);
 }
 
+/**
+ * iwl4965_tx_queue_update_write_ptr - Send new write index to hardware
+ */
 static int iwl4965_tx_queue_update_write_ptr(struct iwl4965_priv *priv,
 				  struct iwl4965_tx_queue *txq)
 {
@@ -5282,6 +5406,11 @@ static void iwl4965_init_band_reference(const struct iwl4965_priv *priv,
 	}
 }
 
+/**
+ * iwl4965_get_channel_info - Find driver's private channel info
+ *
+ * Based on band and channel number.
+ */
 const struct iwl4965_channel_info *iwl4965_get_channel_info(const struct iwl4965_priv *priv,
 						    int phymode, u16 channel)
 {
@@ -5309,6 +5438,9 @@ const struct iwl4965_channel_info *iwl4965_get_channel_info(const struct iwl4965
 #define CHECK_AND_PRINT(x) ((eeprom_ch_info[ch].flags & EEPROM_CHANNEL_##x) \
 			    ? # x " " : "")
 
+/**
+ * iwl4965_init_channel_map - Set up driver's info for all possible channels
+ */
 static int iwl4965_init_channel_map(struct iwl4965_priv *priv)
 {
 	int eeprom_ch_count = 0;
@@ -5418,6 +5550,7 @@ static int iwl4965_init_channel_map(struct iwl4965_priv *priv)
 		}
 	}
 
+	/* Two additional EEPROM bands for 2.4 and 5 GHz FAT channels */
 	for (band = 6; band <= 7; band++) {
 		int phymode;
 		u8 fat_extension_chan;
@@ -5425,7 +5558,9 @@ static int iwl4965_init_channel_map(struct iwl4965_priv *priv)
 		iwl4965_init_band_reference(priv, band, &eeprom_ch_count,
 					&eeprom_ch_info, &eeprom_ch_index);
 
+		/* EEPROM band 6 is 2.4, band 7 is 5 GHz */
 		phymode = (band == 6) ? MODE_IEEE80211B : MODE_IEEE80211A;
+
 		/* Loop through each band adding each of the channels */
 		for (ch = 0; ch < eeprom_ch_count; ch++) {
 
@@ -5437,11 +5572,13 @@ static int iwl4965_init_channel_map(struct iwl4965_priv *priv)
 			else
 				fat_extension_chan = HT_IE_EXT_CHANNEL_ABOVE;
 
+			/* Set up driver's info for lower half */
 			iwl4965_set_fat_chan_info(priv, phymode,
 						  eeprom_ch_index[ch],
 						  &(eeprom_ch_info[ch]),
 						  fat_extension_chan);
 
+			/* Set up driver's info for upper half */
 			iwl4965_set_fat_chan_info(priv, phymode,
 						  (eeprom_ch_index[ch] + 4),
 						  &(eeprom_ch_info[ch]),
@@ -8951,6 +9088,8 @@ static int iwl4965_pci_probe(struct pci_dev *pdev, const struct pci_device_id *e
 	struct ieee80211_hw *hw;
 	int i;
 
+	/* Disabling hardware scan means that mac80211 will perform scans
+	 * "the hard way", rather than using device's scan. */
 	if (iwl4965_param_disable_hw_scan) {
 		IWL_DEBUG_INFO("Disabling hw_scan\n");
 		iwl4965_hw_ops.hw_scan = NULL;
@@ -9002,9 +9141,11 @@ static int iwl4965_pci_probe(struct pci_dev *pdev, const struct pci_device_id *e
 	/* Tell mac80211 our Tx characteristics */
 	hw->flags = IEEE80211_HW_HOST_GEN_BEACON_TEMPLATE;
 
+	/* Default value; 4 EDCA QOS priorities */
 	hw->queues = 4;
 #ifdef CONFIG_IWL4965_HT
 #ifdef CONFIG_IWL4965_HT_AGG
+	/* Enhanced value; more queues, to support 11n aggregation */
 	hw->queues = 16;
 #endif /* CONFIG_IWL4965_HT_AGG */
 #endif /* CONFIG_IWL4965_HT */
@@ -9028,6 +9169,7 @@ static int iwl4965_pci_probe(struct pci_dev *pdev, const struct pci_device_id *e
 
 	pci_set_master(pdev);
 
+	/* Clear the driver's (not device's) station table */
 	iwl4965_clear_stations_table(priv);
 
 	priv->data_retry_limit = -1;
@@ -9047,9 +9189,11 @@ static int iwl4965_pci_probe(struct pci_dev *pdev, const struct pci_device_id *e
 	err = pci_request_regions(pdev, DRV_NAME);
 	if (err)
 		goto out_pci_disable_device;
+
 	/* We disable the RETRY_TIMEOUT register (0x41) to keep
 	 * PCI Tx retries from interfering with C3 CPU state */
 	pci_write_config_byte(pdev, 0x41, 0x00);
+
 	priv->hw_base = pci_iomap(pdev, 0, 0);
 	if (!priv->hw_base) {
 		err = -ENODEV;
@@ -9062,6 +9206,7 @@ static int iwl4965_pci_probe(struct pci_dev *pdev, const struct pci_device_id *e
 
 	/* Initialize module parameter values here */
 
+	/* Disable radio (SW RF KILL) via parameter when loading driver */
 	if (iwl4965_param_disable) {
 		set_bit(STATUS_RF_KILL_SW, &priv->status);
 		IWL_DEBUG_INFO("Radio disabled.\n");
@@ -9076,6 +9221,7 @@ static int iwl4965_pci_probe(struct pci_dev *pdev, const struct pci_device_id *e
 	priv->valid_antenna = 0x7;	/* assume all 3 connected */
 	priv->ps_mode = IWL_MIMO_PS_NONE;
 
+	/* Choose which receivers/antennas to use */
 	iwl4965_set_rxon_chain(priv);
 
 	printk(KERN_INFO DRV_NAME