[PATCH 1/2] rt2x00 : hw support txdone implementation. (without fallback change)

[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.

Ivo: in previous patch I forgot about your comment months ago against the
fallback meaning change. This version thus avoid this change.

Signed-off-by: Benoit Papillault <benoit.papillault@free.fr>
Signed-off-by: Alban Browaeys <prahal@yahoo.com>
---
  drivers/net/wireless/rt2x00/rt2800pci.c |   86 +++++++++++++------------------
  1 files changed, 36 insertions(+), 50 deletions(-)

diff --git a/drivers/net/wireless/rt2x00/rt2800pci.c b/drivers/net/wireless/rt2x00/rt2800pci.c
index 7899789..46b06af 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->hw->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