rt2x00: Split rt2x00lib_write_tx_desc()

Split rt2x00lib_write_tx_desc() up into a TX descriptor initializor
and TX descriptor writer.

This split is required to properly allow mac80211 to move its
tx_control structure into the skb->cb array.
The rt2x00queue_create_tx_descriptor() function will read all tx control
information and convert it into a rt2x00 TX descriptor information structure.
After that function is complete, we have all information we needed from the
tx control structure and are free to start writing into the skb->cb array
for our own purposes.
rt2x00queue_write_tx_descriptor() will be in charge of really sending
the TX descriptor to the hardware and kicking the TX queue.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2400pci.c

@@ -1492,12 +1492,21 @@ static int rt2400pci_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb,
 	struct rt2x00_intf *intf = vif_to_intf(control->vif);
 	struct queue_entry_priv_pci_tx *priv_tx;
 	struct skb_frame_desc *skbdesc;
+	struct txentry_desc txdesc;
 	u32 reg;
 
 	if (unlikely(!intf->beacon))
 		return -ENOBUFS;
 	priv_tx = intf->beacon->priv_data;
 
+	/*
+	 * Copy all TX descriptor information into txdesc,
+	 * after that we are free to use the skb->cb array
+	 * for our information.
+	 */
+	intf->beacon->skb = skb;
+	rt2x00queue_create_tx_descriptor(intf->beacon, &txdesc, control);
+
 	/*
 	 * Fill in skb descriptor
 	 */
@@ -1525,8 +1534,8 @@ static int rt2400pci_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb,
 	 * Write entire beacon with descriptor to register,
 	 * and kick the beacon generator.
 	 */
-	rt2x00lib_write_tx_desc(rt2x00dev, skb, control);
 	memcpy(priv_tx->data, skb->data, skb->len);
+	rt2x00queue_write_tx_descriptor(intf->beacon, &txdesc);
 	rt2x00dev->ops->lib->kick_tx_queue(rt2x00dev, QID_BEACON);
 
 	return 0;

drivers/net/wireless/rt2x00/rt2500pci.c

@@ -1808,13 +1808,22 @@ static int rt2500pci_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb,
 	struct rt2x00_intf *intf = vif_to_intf(control->vif);
 	struct queue_entry_priv_pci_tx *priv_tx;
 	struct skb_frame_desc *skbdesc;
+	struct txentry_desc txdesc;
 	u32 reg;
 
 	if (unlikely(!intf->beacon))
 		return -ENOBUFS;
 
 	priv_tx = intf->beacon->priv_data;
 
+	/*
+	 * Copy all TX descriptor information into txdesc,
+	 * after that we are free to use the skb->cb array
+	 * for our information.
+	 */
+	intf->beacon->skb = skb;
+	rt2x00queue_create_tx_descriptor(intf->beacon, &txdesc, control);
+
 	/*
 	 * Fill in skb descriptor
 	 */
@@ -1842,8 +1851,8 @@ static int rt2500pci_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb,
 	 * Write entire beacon with descriptor to register,
 	 * and kick the beacon generator.
 	 */
-	rt2x00lib_write_tx_desc(rt2x00dev, skb, control);
 	memcpy(priv_tx->data, skb->data, skb->len);
+	rt2x00queue_write_tx_descriptor(intf->beacon, &txdesc);
 	rt2x00dev->ops->lib->kick_tx_queue(rt2x00dev, QID_BEACON);
 
 	return 0;

drivers/net/wireless/rt2x00/rt2500usb.c

@@ -1676,6 +1676,7 @@ static int rt2500usb_beacon_update(struct ieee80211_hw *hw,
 	struct rt2x00_intf *intf = vif_to_intf(control->vif);
 	struct queue_entry_priv_usb_bcn *priv_bcn;
 	struct skb_frame_desc *skbdesc;
+	struct txentry_desc txdesc;
 	int pipe = usb_sndbulkpipe(usb_dev, 1);
 	int length;
 	u16 reg;
@@ -1685,6 +1686,14 @@ static int rt2500usb_beacon_update(struct ieee80211_hw *hw,
 
 	priv_bcn = intf->beacon->priv_data;
 
+	/*
+	 * Copy all TX descriptor information into txdesc,
+	 * after that we are free to use the skb->cb array
+	 * for our information.
+	 */
+	intf->beacon->skb = skb;
+	rt2x00queue_create_tx_descriptor(intf->beacon, &txdesc, control);
+
 	/*
 	 * Add the descriptor in front of the skb.
 	 */
@@ -1713,7 +1722,7 @@ static int rt2500usb_beacon_update(struct ieee80211_hw *hw,
 	rt2x00_set_field16(&reg, TXRX_CSR19_BEACON_GEN, 0);
 	rt2500usb_register_write(rt2x00dev, TXRX_CSR19, reg);
 
-	rt2x00lib_write_tx_desc(rt2x00dev, skb, control);
+	rt2x00queue_write_tx_descriptor(intf->beacon, &txdesc);
 
 	/*
 	 * USB devices cannot blindly pass the skb->len as the

drivers/net/wireless/rt2x00/rt2x00.h

@@ -926,6 +926,41 @@ static inline u16 get_duration_res(const unsigned int size, const u8 rate)
 	return ((size * 8 * 10) % rate);
 }
 
+/**
+ * rt2x00queue_create_tx_descriptor - Create TX descriptor from mac80211 input
+ * @entry: The entry which will be used to transfer the TX frame.
+ * @txdesc: rt2x00 TX descriptor which will be initialized by this function.
+ * @control: mac80211 TX control structure from where we read the information.
+ *
+ * This function will initialize the &struct txentry_desc based on information
+ * from mac80211. This descriptor can then be used by rt2x00lib and the drivers
+ * to correctly initialize the hardware descriptor.
+ * Note that before calling this function the skb->cb array must be untouched
+ * by rt2x00lib. Only after this function completes will it be save to
+ * overwrite the skb->cb information.
+ * The reason for this is that mac80211 writes its own tx information into
+ * the skb->cb array, and this function will use that information to initialize
+ * the &struct txentry_desc structure.
+ */
+void rt2x00queue_create_tx_descriptor(struct queue_entry *entry,
+				      struct txentry_desc *txdesc,
+				      struct ieee80211_tx_control *control);
+
+/**
+ * rt2x00queue_write_tx_descriptor - Write TX descriptor to hardware
+ * @entry: The entry which will be used to transfer the TX frame.
+ * @txdesc: TX descriptor which will be used to write hardware descriptor
+ *
+ * This function will write a TX descriptor initialized by
+ * &rt2x00queue_create_tx_descriptor to the hardware. After this call
+ * has completed the frame is now owned by the hardware, the hardware
+ * queue will have automatically be kicked unless this frame was generated
+ * by rt2x00lib, in which case the frame is "special" and must be kicked
+ * by the caller.
+ */
+void rt2x00queue_write_tx_descriptor(struct queue_entry *entry,
+				     struct txentry_desc *txdesc);
+
 /**
  * rt2x00queue_get_queue - Convert queue index to queue pointer
  * @rt2x00dev: Pointer to &struct rt2x00_dev.
@@ -963,13 +998,6 @@ void rt2x00lib_txdone(struct queue_entry *entry,
 void rt2x00lib_rxdone(struct queue_entry *entry,
 		      struct rxdone_entry_desc *rxdesc);
 
-/*
- * TX descriptor initializer
- */
-void rt2x00lib_write_tx_desc(struct rt2x00_dev *rt2x00dev,
-			     struct sk_buff *skb,
-			     struct ieee80211_tx_control *control);
-
 /*
  * mac80211 handlers.
  */

drivers/net/wireless/rt2x00/rt2x00dev.c

@@ -611,154 +611,6 @@ void rt2x00lib_rxdone(struct queue_entry *entry,
 }
 EXPORT_SYMBOL_GPL(rt2x00lib_rxdone);
 
-/*
- * TX descriptor initializer
- */
-void rt2x00lib_write_tx_desc(struct rt2x00_dev *rt2x00dev,
-			     struct sk_buff *skb,
-			     struct ieee80211_tx_control *control)
-{
-	struct txentry_desc txdesc;
-	struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
-	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skbdesc->data;
-	const struct rt2x00_rate *rate;
-	int tx_rate;
-	int length;
-	int duration;
-	int residual;
-	u16 frame_control;
-	u16 seq_ctrl;
-
-	memset(&txdesc, 0, sizeof(txdesc));
-
-	txdesc.queue = skbdesc->entry->queue->qid;
-	txdesc.cw_min = skbdesc->entry->queue->cw_min;
-	txdesc.cw_max = skbdesc->entry->queue->cw_max;
-	txdesc.aifs = skbdesc->entry->queue->aifs;
-
-	/*
-	 * Read required fields from ieee80211 header.
-	 */
-	frame_control = le16_to_cpu(hdr->frame_control);
-	seq_ctrl = le16_to_cpu(hdr->seq_ctrl);
-
-	tx_rate = control->tx_rate->hw_value;
-
-	/*
-	 * Check whether this frame is to be acked
-	 */
-	if (!(control->flags & IEEE80211_TXCTL_NO_ACK))
-		__set_bit(ENTRY_TXD_ACK, &txdesc.flags);
-
-	/*
-	 * Check if this is a RTS/CTS frame
-	 */
-	if (is_rts_frame(frame_control) || is_cts_frame(frame_control)) {
-		__set_bit(ENTRY_TXD_BURST, &txdesc.flags);
-		if (is_rts_frame(frame_control)) {
-			__set_bit(ENTRY_TXD_RTS_FRAME, &txdesc.flags);
-			__set_bit(ENTRY_TXD_ACK, &txdesc.flags);
-		} else
-			__clear_bit(ENTRY_TXD_ACK, &txdesc.flags);
-		if (control->rts_cts_rate)
-			tx_rate = control->rts_cts_rate->hw_value;
-	}
-
-	/*
-	 * Determine retry information.
-	 */
-	txdesc.retry_limit = control->retry_limit;
-	if (control->flags & IEEE80211_TXCTL_LONG_RETRY_LIMIT)
-		__set_bit(ENTRY_TXD_RETRY_MODE, &txdesc.flags);
-
-	/*
-	 * Check if more fragments are pending
-	 */
-	if (ieee80211_get_morefrag(hdr)) {
-		__set_bit(ENTRY_TXD_BURST, &txdesc.flags);
-		__set_bit(ENTRY_TXD_MORE_FRAG, &txdesc.flags);
-	}
-
-	/*
-	 * Beacons and probe responses require the tsf timestamp
-	 * to be inserted into the frame.
-	 */
-	if (txdesc.queue == QID_BEACON || is_probe_resp(frame_control))
-		__set_bit(ENTRY_TXD_REQ_TIMESTAMP, &txdesc.flags);
-
-	/*
-	 * Determine with what IFS priority this frame should be send.
-	 * Set ifs to IFS_SIFS when the this is not the first fragment,
-	 * or this fragment came after RTS/CTS.
-	 */
-	if (test_bit(ENTRY_TXD_RTS_FRAME, &txdesc.flags)) {
-		txdesc.ifs = IFS_SIFS;
-	} else if (control->flags & IEEE80211_TXCTL_FIRST_FRAGMENT) {
-		__set_bit(ENTRY_TXD_FIRST_FRAGMENT, &txdesc.flags);
-		txdesc.ifs = IFS_BACKOFF;
-	} else {
-		txdesc.ifs = IFS_SIFS;
-	}
-
-	/*
-	 * PLCP setup
-	 * Length calculation depends on OFDM/CCK rate.
-	 */
-	rate = rt2x00_get_rate(tx_rate);
-	txdesc.signal = rate->plcp;
-	txdesc.service = 0x04;
-
-	length = skbdesc->data_len + FCS_LEN;
-	if (rate->flags & DEV_RATE_OFDM) {
-		__set_bit(ENTRY_TXD_OFDM_RATE, &txdesc.flags);
-
-		txdesc.length_high = (length >> 6) & 0x3f;
-		txdesc.length_low = length & 0x3f;
-	} else {
-		/*
-		 * Convert length to microseconds.
-		 */
-		residual = get_duration_res(length, rate->bitrate);
-		duration = get_duration(length, rate->bitrate);
-
-		if (residual != 0) {
-			duration++;
-
-			/*
-			 * Check if we need to set the Length Extension
-			 */
-			if (rate->bitrate == 110 && residual <= 30)
-				txdesc.service |= 0x80;
-		}
-
-		txdesc.length_high = (duration >> 8) & 0xff;
-		txdesc.length_low = duration & 0xff;
-
-		/*
-		 * When preamble is enabled we should set the
-		 * preamble bit for the signal.
-		 */
-		if (rt2x00_get_rate_preamble(tx_rate))
-			txdesc.signal |= 0x08;
-	}
-
-	rt2x00dev->ops->lib->write_tx_desc(rt2x00dev, skb, &txdesc);
-
-	/*
-	 * Update queue entry.
-	 */
-	skbdesc->entry->skb = skb;
-
-	/*
-	 * The frame has been completely initialized and ready
-	 * for sending to the device. The caller will push the
-	 * frame to the device, but we are going to push the
-	 * frame to debugfs here.
-	 */
-	rt2x00debug_dump_frame(rt2x00dev, DUMP_FRAME_TX, skb);
-}
-EXPORT_SYMBOL_GPL(rt2x00lib_write_tx_desc);
-
 /*
  * Driver initialization handlers.
  */

drivers/net/wireless/rt2x00/rt2x00pci.c

@@ -41,6 +41,7 @@ int rt2x00pci_write_tx_data(struct rt2x00_dev *rt2x00dev,
 	struct queue_entry *entry = rt2x00queue_get_entry(queue, Q_INDEX);
 	struct queue_entry_priv_pci_tx *priv_tx = entry->priv_data;
 	struct skb_frame_desc *skbdesc;
+	struct txentry_desc txdesc;
 	u32 word;
 
 	if (rt2x00queue_full(queue))
@@ -57,6 +58,14 @@ int rt2x00pci_write_tx_data(struct rt2x00_dev *rt2x00dev,
 		return -EINVAL;
 	}
 
+	/*
+	 * Copy all TX descriptor information into txdesc,
+	 * after that we are free to use the skb->cb array
+	 * for our information.
+	 */
+	entry->skb = skb;
+	rt2x00queue_create_tx_descriptor(entry, &txdesc, control);
+
 	/*
 	 * Fill in skb descriptor
 	 */
@@ -69,8 +78,8 @@ int rt2x00pci_write_tx_data(struct rt2x00_dev *rt2x00dev,
 
 	memcpy(&priv_tx->control, control, sizeof(priv_tx->control));
 	memcpy(priv_tx->data, skb->data, skb->len);
-	rt2x00lib_write_tx_desc(rt2x00dev, skb, control);
 
+	rt2x00queue_write_tx_descriptor(entry, &txdesc);
 	rt2x00queue_index_inc(queue, Q_INDEX);
 
 	return 0;