ar9170: handle overflow in tsf_low register during get_tsf

ar9170_op_get_tsf: handle a carry from TSF_L into TSF_H
by reading TSF_H twice.

Signed-off-by: Joerg Albert <jal2@gmx.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 16 insertions, 8 deletions

diff --git a/drivers/net/wireless/ath/ar9170/main.c b/drivers/net/wireless/ath/ar9170/main.c
index 81c6cf1135bc..de0ba2bf7691 100644
--- a/drivers/net/wireless/ath/ar9170/main.c
+++ b/drivers/net/wireless/ath/ar9170/main.c
@@ -2192,22 +2192,30 @@ static u64 ar9170_op_get_tsf(struct ieee80211_hw *hw)
 {
         struct ar9170 *ar = hw->priv;
         int err;
-        u32 tsf_low;
-        u32 tsf_high;
         u64 tsf;
+#define NR 3
+        static const u32 addr[NR] = { AR9170_MAC_REG_TSF_H,
+                                    AR9170_MAC_REG_TSF_L,
+                                    AR9170_MAC_REG_TSF_H };
+        u32 val[NR];
+        int loops = 0;
 
         mutex_lock(&ar->mutex);
-        err = ar9170_read_reg(ar, AR9170_MAC_REG_TSF_L, &tsf_low);
-        if (!err)
-                err = ar9170_read_reg(ar, AR9170_MAC_REG_TSF_H, &tsf_high);
+
+        while (loops++ < 10) {
+                err = ar9170_read_mreg(ar, NR, addr, val);
+                if (err || val[0] == val[2])
+                        break;
+        }
+
         mutex_unlock(&ar->mutex);
 
         if (WARN_ON(err))
                 return 0;
-
-        tsf = tsf_high;
-        tsf = (tsf << 32) | tsf_low;
+        tsf = val[0];
+        tsf = (tsf << 32) | val[1];
         return tsf;
+#undef NR
 }
 
 static int ar9170_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,