carl9170: remove fast channel change feature

Marco Fonseca reported a issue with his carl9170 device:
"I'm seeing a problem with the carl driver. If I change channels
repeatedly on the 2.4ghz band, monitoring (e.g. tcpdump) will
eventually halt.  I've seen this on various versions of the carl
driver/firmware (both from 1.9.4 to 1.9.7)"
<http://marc.info/?l=linux-wireless&m=136381302428113>

The culprit was identified as "fast channel change feature" which
according to Adrian Chadd is: "... notoriously unreliable and
really only fully debugged on some very later chips."
<http://marc.info/?l=linux-wireless&m=136416984531380>

Therefore, this patch removes the fast channel change feature.
The phy will now always have to go through a cold reset when
changing channels, but it should no longer become deaf.

Cc: Marco Fonseca <marco@tampabay.rr.com>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 27 insertions, 66 deletions

diff --git a/drivers/net/wireless/ath/carl9170/carl9170.h b/drivers/net/wireless/ath/carl9170/carl9170.h
index 25599741cd8a..9dce106cd6d4 100644
--- a/drivers/net/wireless/ath/carl9170/carl9170.h
+++ b/drivers/net/wireless/ath/carl9170/carl9170.h
@@ -70,12 +70,6 @@
 
 static const u8 ar9170_qmap[__AR9170_NUM_TXQ] = { 3, 2, 1, 0 };
 
-enum carl9170_rf_init_mode {
-        CARL9170_RFI_NONE,
-        CARL9170_RFI_WARM,
-        CARL9170_RFI_COLD,
-};
-
 #define CARL9170_MAX_RX_BUFFER_SIZE             8192
 
 enum carl9170_device_state {
@@ -599,7 +593,7 @@ int carl9170_led_set_state(struct ar9170 *ar, const u32 led_state);
 
 /* PHY / RF */
 int carl9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
-        enum nl80211_channel_type bw, enum carl9170_rf_init_mode rfi);
+                         enum nl80211_channel_type bw);
 int carl9170_get_noisefloor(struct ar9170 *ar);
 
 /* FW */
diff --git a/drivers/net/wireless/ath/carl9170/debug.c b/drivers/net/wireless/ath/carl9170/debug.c
index 93fe6003a493..40109be81f7c 100644
--- a/drivers/net/wireless/ath/carl9170/debug.c
+++ b/drivers/net/wireless/ath/carl9170/debug.c
@@ -655,7 +655,7 @@ static ssize_t carl9170_debugfs_bug_write(struct ar9170 *ar, const char *buf,
 
         case 'P':
                 err = carl9170_set_channel(ar, ar->hw->conf.channel,
-                        ar->hw->conf.channel_type, CARL9170_RFI_COLD);
+                                           ar->hw->conf.channel_type);
                 if (err < 0)
                         count = err;
 
diff --git a/drivers/net/wireless/ath/carl9170/main.c b/drivers/net/wireless/ath/carl9170/main.c
index 08b193199946..699c557bc2c7 100644
--- a/drivers/net/wireless/ath/carl9170/main.c
+++ b/drivers/net/wireless/ath/carl9170/main.c
@@ -939,7 +939,7 @@ static int carl9170_op_config(struct ieee80211_hw *hw, u32 changed)
                         goto out;
 
                 err = carl9170_set_channel(ar, hw->conf.channel,
-                        hw->conf.channel_type, CARL9170_RFI_NONE);
+                                           hw->conf.channel_type);
                 if (err)
                         goto out;
 
diff --git a/drivers/net/wireless/ath/carl9170/phy.c b/drivers/net/wireless/ath/carl9170/phy.c
index b72c09cf43a4..07f82234c860 100644
--- a/drivers/net/wireless/ath/carl9170/phy.c
+++ b/drivers/net/wireless/ath/carl9170/phy.c
@@ -1569,16 +1569,14 @@ static enum carl9170_bw nl80211_to_carl(enum nl80211_channel_type type)
 }
 
 int carl9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
-                         enum nl80211_channel_type _bw,
-                         enum carl9170_rf_init_mode rfi)
+                         enum nl80211_channel_type _bw)
 {
         const struct carl9170_phy_freq_params *freqpar;
         struct carl9170_rf_init_result rf_res;
         struct carl9170_rf_init rf;
-        u32 cmd, tmp, offs = 0, new_ht = 0;
+        u32 tmp, offs = 0, new_ht = 0;
         int err;
         enum carl9170_bw bw;
-        bool warm_reset;
         struct ieee80211_channel *old_channel = NULL;
 
         bw = nl80211_to_carl(_bw);
@@ -1592,51 +1590,27 @@ int carl9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
         /* may be NULL at first setup */
         if (ar->channel) {
                 old_channel = ar->channel;
-                warm_reset = (old_channel->band != channel->band) ||
-                             (old_channel->center_freq ==
-                              channel->center_freq) ||
-                             (ar->ht_settings != new_ht);
-
                 ar->channel = NULL;
-        } else {
-                warm_reset = true;
         }
 
-        /* HW workaround */
-        if (!ar->hw->wiphy->bands[IEEE80211_BAND_5GHZ] &&
-            channel->center_freq <= 2417)
-                warm_reset = true;
-
-        if (rfi != CARL9170_RFI_NONE || warm_reset) {
-                u32 val;
-
-                if (rfi == CARL9170_RFI_COLD)
-                        val = AR9170_PWR_RESET_BB_COLD_RESET;
-                else
-                        val = AR9170_PWR_RESET_BB_WARM_RESET;
-
-                /* warm/cold reset BB/ADDA */
-                err = carl9170_write_reg(ar, AR9170_PWR_REG_RESET, val);
-                if (err)
-                        return err;
-
-                err = carl9170_write_reg(ar, AR9170_PWR_REG_RESET, 0x0);
-                if (err)
-                        return err;
+        /* cold reset BB/ADDA */
+        err = carl9170_write_reg(ar, AR9170_PWR_REG_RESET,
+                                 AR9170_PWR_RESET_BB_COLD_RESET);
+        if (err)
+                return err;
 
-                err = carl9170_init_phy(ar, channel->band);
-                if (err)
-                        return err;
+        err = carl9170_write_reg(ar, AR9170_PWR_REG_RESET, 0x0);
+        if (err)
+                return err;
 
-                err = carl9170_init_rf_banks_0_7(ar,
-                        channel->band == IEEE80211_BAND_5GHZ);
-                if (err)
-                        return err;
+        err = carl9170_init_phy(ar, channel->band);
+        if (err)
+                return err;
 
-                cmd = CARL9170_CMD_RF_INIT;
-        } else {
-                cmd = CARL9170_CMD_FREQUENCY;
-        }
+        err = carl9170_init_rf_banks_0_7(ar,
+                                         channel->band == IEEE80211_BAND_5GHZ);
+        if (err)
+                return err;
 
         err = carl9170_exec_cmd(ar, CARL9170_CMD_FREQ_START, 0, NULL, 0, NULL);
         if (err)
@@ -1648,8 +1622,8 @@ int carl9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
                 return err;
 
         err = carl9170_init_rf_bank4_pwr(ar,
-                channel->band == IEEE80211_BAND_5GHZ,
-                channel->center_freq, bw);
+                                         channel->band == IEEE80211_BAND_5GHZ,
+                                         channel->center_freq, bw);
         if (err)
                 return err;
 
@@ -1703,13 +1677,8 @@ int carl9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
         rf.delta_slope_coeff_man = cpu_to_le32(freqpar->coeff_man);
         rf.delta_slope_coeff_exp_shgi = cpu_to_le32(freqpar->coeff_exp_shgi);
         rf.delta_slope_coeff_man_shgi = cpu_to_le32(freqpar->coeff_man_shgi);
-
-        if (rfi != CARL9170_RFI_NONE)
-                rf.finiteLoopCount = cpu_to_le32(2000);
-        else
-                rf.finiteLoopCount = cpu_to_le32(1000);
-
-        err = carl9170_exec_cmd(ar, cmd, sizeof(rf), &rf,
+        rf.finiteLoopCount = cpu_to_le32(2000);
+        err = carl9170_exec_cmd(ar, CARL9170_CMD_RF_INIT, sizeof(rf), &rf,
                                 sizeof(rf_res), &rf_res);
         if (err)
                 return err;
@@ -1724,9 +1693,8 @@ int carl9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
                           old_channel->center_freq : -1, channel->center_freq,
                           err);
 
-                if ((rfi == CARL9170_RFI_COLD) || (ar->chan_fail > 3)) {
-                        /*
-                         * We have tried very hard to change to _another_
+                if (ar->chan_fail > 3) {
+                        /* We have tried very hard to change to _another_
                          * channel and we've failed to do so!
                          * Chances are that the PHY/RF is no longer
                          * operable (due to corruptions/fatal events/bugs?)
@@ -1736,8 +1704,7 @@ int carl9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
                         return 0;
                 }
 
-                err = carl9170_set_channel(ar, channel, _bw,
-                                           CARL9170_RFI_COLD);
+                err = carl9170_set_channel(ar, channel, _bw);
                 if (err)
                         return err;
         } else {