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>

1 files changed, 9 insertions, 14 deletions

diff --git a/drivers/net/wireless/rt2x00/rt61pci.c b/drivers/net/wireless/rt2x00/rt61pci.c
index d1270118f7d3..7ca383478eeb 100644
--- 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.