rt2x00: Limit TX done looping to number of TX ring entries

Similar to rt2800pci, remove the check for duplicate
register reading, and instead limit the for-loop to
the maximum number of TX entries inside a queue.

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

diff --git a/drivers/net/wireless/rt2x00/rt61pci.c b/drivers/net/wireless/rt2x00/rt61pci.c
index d1270118f7d3738afcfdaa5aad639fdcb8a8b34d..7ca383478eeb9a24d8d15d87968ec325619b7f4f 100644 (file)
--- a/drivers/net/wireless/rt2x00/rt61pci.c
+++ b/drivers/net/wireless/rt2x00/rt61pci.c
@@ -2052,29 +2052,24 @@ static void rt61pci_txdone(struct rt2x00_dev *rt2x00dev)
        struct txdone_entry_desc txdesc;
        u32 word;
        u32 reg;
-       u32 old_reg;
        int type;
        int index;
+       int i;
 
        /*
-        * During each loop we will compare the freshly read
-        * STA_CSR4 register value with the value read from
-        * the previous loop. If the 2 values are equal then
-        * we should stop processing because the chance is
-        * quite big that the device has been unplugged and
-        * we risk going into an endless loop.
+        * TX_STA_FIFO is a stack of X entries, hence read TX_STA_FIFO
+        * at most X times and also stop processing once the TX_STA_FIFO_VALID
+        * flag is not set anymore.
+        *
+        * The legacy drivers use X=TX_RING_SIZE but state in a comment
+        * that the TX_STA_FIFO stack has a size of 16. We stick to our
+        * tx ring size for now.
         */
-       old_reg = 0;
-
-       while (1) {
+       for (i = 0; i < TX_ENTRIES; i++) {
                rt2x00pci_register_read(rt2x00dev, STA_CSR4, &reg);
                if (!rt2x00_get_field32(reg, STA_CSR4_VALID))
                        break;
 
-               if (old_reg == reg)
-                       break;
-               old_reg = reg;
-
                /*
                 * Skip this entry when it contains an invalid
                 * queue identication number.