ath9k: Add a few comments about mibevents

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath9k/hw.c b/drivers/net/wireless/ath9k/hw.c
index 0251e59f2f849a109e67d6f43a3297cd206136ad..272c758166091033b4b64889830434143a140cf6 100644 (file)
--- a/drivers/net/wireless/ath9k/hw.c
+++ b/drivers/net/wireless/ath9k/hw.c
@@ -2526,6 +2526,11 @@ static void ath9k_ani_reset(struct ath_hal *ah)
        }
 }
 
+/*
+ * Process a MIB interrupt.  We may potentially be invoked because
+ * any of the MIB counters overflow/trigger so don't assume we're
+ * here because a PHY error counter triggered.
+ */
 void ath9k_hw_procmibevent(struct ath_hal *ah,
                           const struct ath9k_node_stats *stats)
 {
@@ -2533,18 +2538,20 @@ void ath9k_hw_procmibevent(struct ath_hal *ah,
        u32 phyCnt1, phyCnt2;
 
        DPRINTF(ah->ah_sc, ATH_DBG_ANI, "Processing Mib Intr\n");
-
+       /* Reset these counters regardless */
        REG_WRITE(ah, AR_FILT_OFDM, 0);
        REG_WRITE(ah, AR_FILT_CCK, 0);
        if (!(REG_READ(ah, AR_SLP_MIB_CTRL) & AR_SLP_MIB_PENDING))
                REG_WRITE(ah, AR_SLP_MIB_CTRL, AR_SLP_MIB_CLEAR);
 
+       /* Clear the mib counters and save them in the stats */
        ath9k_hw_update_mibstats(ah, &ahp->ah_mibStats);
        ahp->ah_stats.ast_nodestats = *stats;
 
        if (!DO_ANI(ah))
                return;
 
+       /* NB: these are not reset-on-read */
        phyCnt1 = REG_READ(ah, AR_PHY_ERR_1);
        phyCnt2 = REG_READ(ah, AR_PHY_ERR_2);
        if (((phyCnt1 & AR_MIBCNT_INTRMASK) == AR_MIBCNT_INTRMASK) ||
@@ -2552,6 +2559,7 @@ void ath9k_hw_procmibevent(struct ath_hal *ah,
                struct ar5416AniState *aniState = ahp->ah_curani;
                u32 ofdmPhyErrCnt, cckPhyErrCnt;
 
+               /* NB: only use ast_ani_*errs with AH_PRIVATE_DIAG */
                ofdmPhyErrCnt = phyCnt1 - aniState->ofdmPhyErrBase;
                ahp->ah_stats.ast_ani_ofdmerrs +=
                        ofdmPhyErrCnt - aniState->ofdmPhyErrCount;
@@ -2562,11 +2570,17 @@ void ath9k_hw_procmibevent(struct ath_hal *ah,
                        cckPhyErrCnt - aniState->cckPhyErrCount;
                aniState->cckPhyErrCount = cckPhyErrCnt;
 
+               /*
+                * NB: figure out which counter triggered.  If both
+                * trigger we'll only deal with one as the processing
+                * clobbers the error counter so the trigger threshold
+                * check will never be true.
+                */
                if (aniState->ofdmPhyErrCount > aniState->ofdmTrigHigh)
                        ath9k_hw_ani_ofdm_err_trigger(ah);
                if (aniState->cckPhyErrCount > aniState->cckTrigHigh)
                        ath9k_hw_ani_cck_err_trigger(ah);
-
+               /* NB: always restart to insure the h/w counters are reset */
                ath9k_ani_restart(ah);
        }
 }