[PATCH] rt2x00 : hw support txdone implementation.

[Alban Browaeys <prahal@yahoo.com>]

This is an implementation that support WCID being the key_index coming
from benoit without the change in the meaning of the tx fallback flag.
It replaces the software only implementation by an implementation
supporting HW encryption.
It fixes the mixes of usage of WCID behing set to the key_idx and
then getting used as the entry index in the queue.

Signed-off-by: Benoit Papillault <benoit.papillault@free.fr>
Signed-off-by: Alban Browaeys <prahal@yahoo.com>
---
  drivers/net/wireless/rt2x00/rt2800pci.c |   82 +++++++++++++------------------
  1 files changed, 34 insertions(+), 48 deletions(-)

diff --git a/drivers/net/wireless/rt2x00/rt2800pci.c b/drivers/net/wireless/rt2x00/rt2800pci.c
index 7899789..39ea72b 100644
--- a/drivers/net/wireless/rt2x00/rt2800pci.c
+++ b/drivers/net/wireless/rt2x00/rt2800pci.c
@@ -920,76 +920,61 @@ static void rt2800pci_txdone(struct rt2x00_dev *rt2x00dev)
  {
  	struct data_queue *queue;
  	struct queue_entry *entry;
-	struct queue_entry *entry_done;
-	struct queue_entry_priv_pci *entry_priv;
+	__le32 *txwi;
  	struct txdone_entry_desc txdesc;
  	u32 word;
  	u32 reg;
-	u32 old_reg;
-	unsigned int type;
-	unsigned int index;
-	u16 mcs, real_mcs;
+	int i;
+	int wcid, ack, pid, tx_wcid, tx_ack, tx_pid;
+	u16 mcs, tx_mcs;
  
  	/*
-	 * During each loop we will compare the freshly read
-	 * TX_STA_FIFO register value with the value read from
-	 * the previous loop. If the 2 values are equal then
-	 * we should stop processing because the chance it
-	 * quite big that the device has been unplugged and
-	 * we risk going into an endless loop.
+	 * To avoid an endlees loop, we only read the TX_STA_FIFO register up
+	 * to 256 times (this is enought to get all values from the FIFO). In
+	 * normal situation, the loop is terminated when we reach a value with
+	 * TX_STA_FIFO_VALID bit is 0.
  	 */
-	old_reg = 0;
  
-	while (1) {
+	for (i = 0; i < 256; i++) {
  		rt2800_register_read(rt2x00dev, TX_STA_FIFO, &reg);
  		if (!rt2x00_get_field32(reg, TX_STA_FIFO_VALID))
  			break;
  
-		if (old_reg == reg)
-			break;
-		old_reg = reg;
+		wcid    = rt2x00_get_field32(reg, TX_STA_FIFO_WCID);
+		ack     = rt2x00_get_field32(reg, TX_STA_FIFO_TX_ACK_REQUIRED);
+		pid     = rt2x00_get_field32(reg, TX_STA_FIFO_PID_TYPE);
  
  		/*
  		 * Skip this entry when it contains an invalid
  		 * queue identication number.
  		 */
-		type = rt2x00_get_field32(reg, TX_STA_FIFO_PID_TYPE) - 1;
-		if (type >= QID_RX)
+		if (pid < 1)
  			continue;
  
-		queue = rt2x00queue_get_queue(rt2x00dev, type);
+		queue = rt2x00queue_get_queue(rt2x00dev, pid - 1);
  		if (unlikely(!queue))
  			continue;
  
  		/*
-		 * Skip this entry when it contains an invalid
-		 * index number.
+		 * Inside each queue, we process each entry in a chronological
+		 * order. We first check that the queue is not empty.
  		 */
-		index = rt2x00_get_field32(reg, TX_STA_FIFO_WCID) - 1;
-		if (unlikely(index >= queue->limit))
+		if (queue->length == 0)
  			continue;
+		entry = rt2x00queue_get_entry(queue, Q_INDEX_DONE);
  
-		entry = &queue->entries[index];
-		entry_priv = entry->priv_data;
-		rt2x00_desc_read((__le32 *)entry->skb->data, 0, &word);
-
-		entry_done = rt2x00queue_get_entry(queue, Q_INDEX_DONE);
-		while (entry != entry_done) {
-			/*
-			 * Catch up.
-			 * Just report any entries we missed as failed.
-			 */
-			WARNING(rt2x00dev,
-				"TX status report missed for entry %d\n",
-				entry_done->entry_idx);
-
-			txdesc.flags = 0;
-			__set_bit(TXDONE_UNKNOWN, &txdesc.flags);
-			txdesc.retry = 0;
-
-			rt2x00lib_txdone(entry_done, &txdesc);
-			entry_done = rt2x00queue_get_entry(queue, Q_INDEX_DONE);
-		}
+		/* Check if we got a match by looking at WCID/ACK/PID
+		 * fields */
+		txwi = (__le32 *)(entry->skb->data -
+				  rt2x00dev->ops->extra_tx_headroom);
+
+		rt2x00_desc_read(txwi, 1, &word);
+		tx_wcid = rt2x00_get_field32(word, TXWI_W1_WIRELESS_CLI_ID);
+		tx_ack  = rt2x00_get_field32(word, TXWI_W1_ACK);
+		tx_pid  = rt2x00_get_field32(word, TXWI_W1_PACKETID);
+
+		if ((wcid != tx_wcid) || (ack != tx_ack) || (pid != tx_pid))
+			WARNING(rt2x00dev, "invalid TX_STA_FIFO content\n");
  
  		/*
  		 * Obtain the status about this packet.
@@ -1010,10 +995,11 @@ static void rt2800pci_txdone(struct rt2x00_dev *rt2x00dev)
  		 * we have mcs = tx_mcs - 1. So the number of
  		 * retry is (tx_mcs - mcs).
  		 */
-		mcs = rt2x00_get_field32(word, TXWI_W0_MCS);
-		real_mcs = rt2x00_get_field32(reg, TX_STA_FIFO_MCS);
+		mcs = rt2x00_get_field32(reg, TX_STA_FIFO_MCS);
+		rt2x00_desc_read(txwi, 0, &word);
+		tx_mcs = rt2x00_get_field32(word, TXWI_W0_MCS);
  		__set_bit(TXDONE_FALLBACK, &txdesc.flags);
-		txdesc.retry = mcs - min(mcs, real_mcs);
+		txdesc.retry = tx_mcs - min(tx_mcs, mcs);
  
  		rt2x00lib_txdone(entry, &txdesc);
  	}
-- 
1.7.0