rt2x00: Simplify TXD handling of beacons.

The handling of tx descriptors for beacons can be simplified by updating
write_tx_desc implementations of each driver to write directly to the
queue entry descriptor instead of to a provided memory area.
This is also a preparation for further clean ups where descriptors are
properly reserved in the skb instead of fiddling with the skb data
pointer.

Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2400pci.c b/drivers/net/wireless/rt2x00/rt2400pci.c
index 1eff6ec..def3fa4 100644
--- a/drivers/net/wireless/rt2x00/rt2400pci.c
+++ b/drivers/net/wireless/rt2x00/rt2400pci.c
@@ -1006,15 +1006,15 @@
 {
 	struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
 	struct queue_entry_priv_pci *entry_priv = skbdesc->entry->priv_data;
-	__le32 *txd = skbdesc->desc;
+	__le32 *txd = entry_priv->desc;
 	u32 word;
 
 	/*
 	 * Start writing the descriptor words.
 	 */
-	rt2x00_desc_read(entry_priv->desc, 1, &word);
+	rt2x00_desc_read(txd, 1, &word);
 	rt2x00_set_field32(&word, TXD_W1_BUFFER_ADDRESS, skbdesc->skb_dma);
-	rt2x00_desc_write(entry_priv->desc, 1, word);
+	rt2x00_desc_write(txd, 1, word);
 
 	rt2x00_desc_read(txd, 2, &word);
 	rt2x00_set_field32(&word, TXD_W2_BUFFER_LENGTH, txdesc->length);
@@ -1059,6 +1059,12 @@
 	rt2x00_set_field32(&word, TXD_W0_RETRY_MODE,
 			   test_bit(ENTRY_TXD_RETRY_MODE, &txdesc->flags));
 	rt2x00_desc_write(txd, 0, word);
+
+	/*
+	 * Register descriptor details in skb frame descriptor.
+	 */
+	skbdesc->desc = txd;
+	skbdesc->desc_len = TXD_DESC_SIZE;
 }
 
 /*
@@ -1081,15 +1087,6 @@
 	rt2x00_set_field32(&reg, CSR14_BEACON_GEN, 0);
 	rt2x00pci_register_write(rt2x00dev, CSR14, reg);
 
-	/*
-	 * Replace rt2x00lib allocated descriptor with the
-	 * pointer to the _real_ hardware descriptor.
-	 * After that, map the beacon to DMA and update the
-	 * descriptor.
-	 */
-	memcpy(entry_priv->desc, skbdesc->desc, skbdesc->desc_len);
-	skbdesc->desc = entry_priv->desc;
-
 	rt2x00queue_map_txskb(rt2x00dev, entry->skb);
 
 	rt2x00_desc_read(entry_priv->desc, 1, &word);