rt2x00: Only initialize the minimum needed fields of PCI TX descriptors.

In preparation of replacing the statically allocated data DMA buffers with DMA-mapped
skb's we need to change the TXD handling of the PCI drivers, by moving the programming
of the buffer address fields to the actual TXD writing at TX time, instead of at start-up
time.

Signed-off-by: Gertjan van Wingerde <gwingerde@kpnplanet.nl>
Signed-off-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 b4310d7..2c0cf39 100644
--- a/drivers/net/wireless/rt2x00/rt2400pci.c
+++ b/drivers/net/wireless/rt2x00/rt2400pci.c
@@ -643,15 +643,6 @@
 	struct queue_entry_priv_pci_tx *priv_tx = entry->priv_data;
 	u32 word;
 
-	rt2x00_desc_read(priv_tx->desc, 1, &word);
-	rt2x00_set_field32(&word, TXD_W1_BUFFER_ADDRESS, priv_tx->data_dma);
-	rt2x00_desc_write(priv_tx->desc, 1, word);
-
-	rt2x00_desc_read(priv_tx->desc, 2, &word);
-	rt2x00_set_field32(&word, TXD_W2_BUFFER_LENGTH,
-			   entry->queue->data_size);
-	rt2x00_desc_write(priv_tx->desc, 2, word);
-
 	rt2x00_desc_read(priv_tx->desc, 0, &word);
 	rt2x00_set_field32(&word, TXD_W0_VALID, 0);
 	rt2x00_set_field32(&word, TXD_W0_OWNER_NIC, 0);
@@ -1004,13 +995,19 @@
 				    struct txentry_desc *txdesc)
 {
 	struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);
+	struct queue_entry_priv_pci_tx *entry_priv = skbdesc->entry->priv_data;
 	__le32 *txd = skbdesc->desc;
 	u32 word;
 
 	/*
 	 * Start writing the descriptor words.
 	 */
+	rt2x00_desc_read(entry_priv->desc, 1, &word);
+	rt2x00_set_field32(&word, TXD_W1_BUFFER_ADDRESS, entry_priv->data_dma);
+	rt2x00_desc_write(entry_priv->desc, 1, word);
+
 	rt2x00_desc_read(txd, 2, &word);
+	rt2x00_set_field32(&word, TXD_W2_BUFFER_LENGTH, skbdesc->data_len);
 	rt2x00_set_field32(&word, TXD_W2_DATABYTE_COUNT, skbdesc->data_len);
 	rt2x00_desc_write(txd, 2, word);