ath5k: Update phy calibration functions

 * Enable I/Q calibration each time we have correction results (we
   were only enabling calibration during reset). If we don't we commit
   the same results each time calibration routine is called.
 * Add some documentation and a TODO on nf calibration
 * Return -EAGAIN on noise floor timeout/failure

Changes-licensed-under: ISC
Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 42 insertions, 12 deletions

diff --git a/drivers/net/wireless/ath5k/phy.c b/drivers/net/wireless/ath5k/phy.c
index cbc362d20719..fa0d47faf574 100644
--- a/drivers/net/wireless/ath5k/phy.c
+++ b/drivers/net/wireless/ath5k/phy.c
@@ -2052,6 +2052,8 @@ int ath5k_hw_channel(struct ath5k_hw *ah, struct ieee80211_channel *channel)
  * http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL \
  * &p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7245893.PN.&OS=PN/7
  *
+ * XXX: Since during noise floor calibration antennas are detached according to
+ * the patent, we should stop tx queues here.
  */
 int
 ath5k_hw_noise_floor_calibration(struct ath5k_hw *ah, short freq)
@@ -2061,7 +2063,7 @@ ath5k_hw_noise_floor_calibration(struct ath5k_hw *ah, short freq)
         s32 noise_floor;
 
         /*
-         * Enable noise floor calibration and wait until completion
+         * Enable noise floor calibration
          */
         AR5K_REG_ENABLE_BITS(ah, AR5K_PHY_AGCCTL,
                                 AR5K_PHY_AGCCTL_NF);
@@ -2071,7 +2073,7 @@ ath5k_hw_noise_floor_calibration(struct ath5k_hw *ah, short freq)
         if (ret) {
                 ATH5K_ERR(ah->ah_sc,
                         "noise floor calibration timeout (%uMHz)\n", freq);
-                return ret;
+                return -EAGAIN;
         }
 
         /* Wait until the noise floor is calibrated and read the value */
@@ -2093,7 +2095,7 @@ ath5k_hw_noise_floor_calibration(struct ath5k_hw *ah, short freq)
         if (noise_floor > AR5K_TUNE_NOISE_FLOOR) {
                 ATH5K_ERR(ah->ah_sc,
                         "noise floor calibration failed (%uMHz)\n", freq);
-                return -EIO;
+                return -EAGAIN;
         }
 
         ah->ah_noise_floor = noise_floor;
@@ -2206,38 +2208,66 @@ static int ath5k_hw_rf5110_calibrate(struct ath5k_hw *ah,
 }
 
 /*
- * Perform a PHY calibration on RF5111/5112
+ * Perform a PHY calibration on RF5111/5112 and newer chips
  */
 static int ath5k_hw_rf511x_calibrate(struct ath5k_hw *ah,
                 struct ieee80211_channel *channel)
 {
         u32 i_pwr, q_pwr;
         s32 iq_corr, i_coff, i_coffd, q_coff, q_coffd;
+        int i;
         ATH5K_TRACE(ah->ah_sc);
 
         if (!ah->ah_calibration ||
-                        ath5k_hw_reg_read(ah, AR5K_PHY_IQ) & AR5K_PHY_IQ_RUN)
+                ath5k_hw_reg_read(ah, AR5K_PHY_IQ) & AR5K_PHY_IQ_RUN)
                 goto done;
 
-        ah->ah_calibration = false;
+        /* Calibration has finished, get the results and re-run */
+        for (i = 0; i <= 10; i++) {
+                iq_corr = ath5k_hw_reg_read(ah, AR5K_PHY_IQRES_CAL_CORR);
+                i_pwr = ath5k_hw_reg_read(ah, AR5K_PHY_IQRES_CAL_PWR_I);
+                q_pwr = ath5k_hw_reg_read(ah, AR5K_PHY_IQRES_CAL_PWR_Q);
+        }
 
-        iq_corr = ath5k_hw_reg_read(ah, AR5K_PHY_IQRES_CAL_CORR);
-        i_pwr = ath5k_hw_reg_read(ah, AR5K_PHY_IQRES_CAL_PWR_I);
-        q_pwr = ath5k_hw_reg_read(ah, AR5K_PHY_IQRES_CAL_PWR_Q);
         i_coffd = ((i_pwr >> 1) + (q_pwr >> 1)) >> 7;
-        q_coffd = q_pwr >> 6;
+        q_coffd = q_pwr >> 7;
 
+        /* No correction */
         if (i_coffd == 0 || q_coffd == 0)
                 goto done;
 
         i_coff = ((-iq_corr) / i_coffd) & 0x3f;
-        q_coff = (((s32)i_pwr / q_coffd) - 64) & 0x1f;
 
-        /* Commit new IQ value */
+        /* Boundary check */
+        if (i_coff > 31)
+                i_coff = 31;
+        if (i_coff < -32)
+                i_coff = -32;
+
+        q_coff = (((s32)i_pwr / q_coffd) - 128) & 0x1f;
+
+        /* Boundary check */
+        if (q_coff > 15)
+                q_coff = 15;
+        if (q_coff < -16)
+                q_coff = -16;
+
+        /* Commit new I/Q value */
         AR5K_REG_ENABLE_BITS(ah, AR5K_PHY_IQ, AR5K_PHY_IQ_CORR_ENABLE |
                 ((u32)q_coff) | ((u32)i_coff << AR5K_PHY_IQ_CORR_Q_I_COFF_S));
 
+        /* Re-enable calibration -if we don't we'll commit
+         * the same values again and again */
+        AR5K_REG_WRITE_BITS(ah, AR5K_PHY_IQ,
+                        AR5K_PHY_IQ_CAL_NUM_LOG_MAX, 15);
+        AR5K_REG_ENABLE_BITS(ah, AR5K_PHY_IQ, AR5K_PHY_IQ_RUN);
+
 done:
+
+        /* TODO: Separate noise floor calibration from I/Q calibration
+         * since noise floor calibration interrupts rx path while I/Q
+         * calibration doesn't. We don't need to run noise floor calibration
+         * as often as I/Q calibration.*/
         ath5k_hw_noise_floor_calibration(ah, channel->center_freq);
 
         /* Request RF gain */