ath9k: Add Calibration checks

* Prevent divide-by-zero errors in IQ Calibration.
* Do not run temperature compensation if initPDADC or currPDADC is zero.
* Also, introduce a separate function for handling OLC for AR9287.

Signed-off-by: Vivek Natarajan <vnatarajan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 50 insertions, 28 deletions

diff --git a/drivers/net/wireless/ath/ath9k/calib.c b/drivers/net/wireless/ath/ath9k/calib.c
index 36c5f89e2fc..9c46b54d2a9 100644
--- a/drivers/net/wireless/ath/ath9k/calib.c
+++ b/drivers/net/wireless/ath/ath9k/calib.c
@@ -403,7 +403,8 @@ static void ath9k_hw_iqcalibrate(struct ath_hw *ah, u8 numChains)
                 iCoffDenom = (powerMeasI / 2 + powerMeasQ / 2) / 128;
                 qCoffDenom = powerMeasQ / 64;
 
-                if (powerMeasQ != 0) {
+                if ((powerMeasQ != 0) && (iCoffDenom != 0) &&
+                    (qCoffDenom != 0)) {
                         iCoff = iqCorrMeas / iCoffDenom;
                         qCoff = powerMeasI / qCoffDenom - 64;
                         ath_print(common, ATH_DBG_CALIBRATE,
@@ -746,44 +747,65 @@ s16 ath9k_hw_getchan_noise(struct ath_hw *ah, struct ath9k_channel *chan)
         return nf;
 }
 
-static void ath9k_olc_temp_compensation(struct ath_hw *ah)
+static void ath9k_olc_temp_compensation_9287(struct ath_hw *ah)
 {
-        u32 rddata, i;
-        int delta, currPDADC, regval, slope;
+        u32 rddata;
+        int32_t delta, currPDADC, slope;
 
         rddata = REG_READ(ah, AR_PHY_TX_PWRCTRL4);
         currPDADC = MS(rddata, AR_PHY_TX_PWRCTRL_PD_AVG_OUT);
 
+        if (ah->initPDADC == 0 || currPDADC == 0) {
+                /*
+                 * Zero value indicates that no frames have been transmitted yet,
+                 * can't do temperature compensation until frames are transmitted.
+                 */
+                return;
+        } else {
+                slope = ah->eep_ops->get_eeprom(ah, EEP_TEMPSENSE_SLOPE);
+
+                if (slope == 0) { /* to avoid divide by zero case */
+                        delta = 0;
+                } else {
+                        delta = ((currPDADC - ah->initPDADC)*4) / slope;
+                }
+                REG_RMW_FIELD(ah, AR_PHY_CH0_TX_PWRCTRL11,
+                              AR_PHY_TX_PWRCTRL_OLPC_TEMP_COMP, delta);
+                REG_RMW_FIELD(ah, AR_PHY_CH1_TX_PWRCTRL11,
+                              AR_PHY_TX_PWRCTRL_OLPC_TEMP_COMP, delta);
+        }
+}
+
+static void ath9k_olc_temp_compensation(struct ath_hw *ah)
+{
+        u32 rddata, i;
+        int delta, currPDADC, regval;
 
         if (OLC_FOR_AR9287_10_LATER) {
+                ath9k_olc_temp_compensation_9287(ah);
+        } else {
+                rddata = REG_READ(ah, AR_PHY_TX_PWRCTRL4);
+                currPDADC = MS(rddata, AR_PHY_TX_PWRCTRL_PD_AVG_OUT);
+
                 if (ah->initPDADC == 0 || currPDADC == 0) {
                         return;
                 } else {
-                        slope = ah->eep_ops->get_eeprom(ah, EEP_TEMPSENSE_SLOPE);
-                        if (slope == 0)
-                                delta = 0;
+                        if (ah->eep_ops->get_eeprom(ah, EEP_DAC_HPWR_5G))
+                                delta = (currPDADC - ah->initPDADC + 4) / 8;
                         else
-                                delta = ((currPDADC - ah->initPDADC)*4) / slope;
-                        REG_RMW_FIELD(ah, AR_PHY_CH0_TX_PWRCTRL11,
-                                        AR_PHY_TX_PWRCTRL_OLPC_TEMP_COMP, delta);
-                        REG_RMW_FIELD(ah, AR_PHY_CH1_TX_PWRCTRL11,
-                                        AR_PHY_TX_PWRCTRL_OLPC_TEMP_COMP, delta);
-                }
-        } else {
-                if (ah->eep_ops->get_eeprom(ah, EEP_DAC_HPWR_5G))
-                        delta = (currPDADC - ah->initPDADC + 4) / 8;
-                else
-                        delta = (currPDADC - ah->initPDADC + 5) / 10;
-
-                if (delta != ah->PDADCdelta) {
-                        ah->PDADCdelta = delta;
-                        for (i = 1; i < AR9280_TX_GAIN_TABLE_SIZE; i++) {
-                                regval = ah->originalGain[i] - delta;
-                                if (regval < 0)
-                                        regval = 0;
-
-                                REG_RMW_FIELD(ah, AR_PHY_TX_GAIN_TBL1 + i * 4,
-                                                AR_PHY_TX_GAIN, regval);
+                                delta = (currPDADC - ah->initPDADC + 5) / 10;
+
+                        if (delta != ah->PDADCdelta) {
+                                ah->PDADCdelta = delta;
+                                for (i = 1; i < AR9280_TX_GAIN_TABLE_SIZE; i++) {
+                                        regval = ah->originalGain[i] - delta;
+                                        if (regval < 0)
+                                                regval = 0;
+
+                                        REG_RMW_FIELD(ah,
+                                                      AR_PHY_TX_GAIN_TBL1 + i * 4,
+                                                      AR_PHY_TX_GAIN, regval);
+                                }
                         }
                 }
         }