staging: vt6656: CARDqGetNextTBTT replace code using do_div.

uBeaconInterval becomes u32

get next TBTT value using vendor's equation as shown.

This patch was checked against the original code
and yields exactly the same value.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/vt6656/card.c b/drivers/staging/vt6656/card.c
index ce7ee45..0d87728 100644 (file)
--- a/drivers/staging/vt6656/card.c
+++ b/drivers/staging/vt6656/card.c
@@ -720,28 +720,20 @@ bool CARDbClearCurrentTSF(struct vnt_private *pDevice)
  */
 u64 CARDqGetNextTBTT(u64 qwTSF, u16 wBeaconInterval)
 {
+       u32 uBeaconInterval;
 
-    unsigned int    uLowNextTBTT;
-    unsigned int    uHighRemain, uLowRemain;
-    unsigned int    uBeaconInterval;
+       uBeaconInterval = wBeaconInterval * 1024;
 
-    uBeaconInterval = wBeaconInterval * 1024;
-    // Next TBTT = ((local_current_TSF / beacon_interval) + 1 ) * beacon_interval
-       uLowNextTBTT = ((qwTSF & 0xffffffffULL) >> 10) << 10;
-       uLowRemain = (uLowNextTBTT) % uBeaconInterval;
-       uHighRemain = ((0x80000000 % uBeaconInterval) * 2 * (u32)(qwTSF >> 32))
-               % uBeaconInterval;
-       uLowRemain = (uHighRemain + uLowRemain) % uBeaconInterval;
-       uLowRemain = uBeaconInterval - uLowRemain;
-
-    // check if carry when add one beacon interval
-       if ((~uLowNextTBTT) < uLowRemain)
-               qwTSF = ((qwTSF >> 32) + 1) << 32;
-
-       qwTSF = (qwTSF & 0xffffffff00000000ULL) |
-               (u64)(uLowNextTBTT + uLowRemain);
+       /* Next TBTT =
+       *       ((local_current_TSF / beacon_interval) + 1) * beacon_interval
+       */
+       if (uBeaconInterval) {
+               do_div(qwTSF, uBeaconInterval);
+               qwTSF += 1;
+               qwTSF *= uBeaconInterval;
+       }
 
-    return (qwTSF);
+       return qwTSF;
 }
 
 /*