iwlwifi: mvm: rs: refactor rate scale action decision

Extract the scale action decision to a different function
in preparation of modifying it. While at it also convert
the scale action values from hardcoded values to a clear enum.

Signed-off-by: Eyal Shapira <eyal@wizery.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

1 files changed, 103 insertions, 83 deletions

diff --git a/drivers/net/wireless/iwlwifi/mvm/rs.c b/drivers/net/wireless/iwlwifi/mvm/rs.c
index 6d0bd45b0791..62b29d7f80f0 100644
--- a/drivers/net/wireless/iwlwifi/mvm/rs.c
+++ b/drivers/net/wireless/iwlwifi/mvm/rs.c
@@ -130,6 +130,12 @@ static const struct iwl_rs_rate_info iwl_rates[IWL_RATE_COUNT] = {
         IWL_DECLARE_MCS_RATE(9),                 /* MCS 9 */
 };
 
+enum rs_action {
+        RS_ACTION_STAY = 0,
+        RS_ACTION_DOWNSCALE = -1,
+        RS_ACTION_UPSCALE = 1,
+};
+
 enum rs_column_mode {
         RS_INVALID = 0,
         RS_LEGACY,
@@ -1616,6 +1622,97 @@ err:
         return -1;
 }
 
+static enum rs_action rs_get_rate_action(struct iwl_mvm *mvm,
+                                         struct iwl_scale_tbl_info *tbl,
+                                         s32 sr, int low, int high,
+                                         int current_tpt,
+                                         int low_tpt, int high_tpt)
+{
+        enum rs_action action = RS_ACTION_STAY;
+
+        /* Too many failures, decrease rate */
+        if ((sr <= RS_SR_FORCE_DECREASE) || (current_tpt == 0)) {
+                IWL_DEBUG_RATE(mvm,
+                               "decrease rate because of low SR\n");
+                action = RS_ACTION_DOWNSCALE;
+        /* No throughput measured yet for adjacent rates; try increase. */
+        } else if ((low_tpt == IWL_INVALID_VALUE) &&
+                   (high_tpt == IWL_INVALID_VALUE)) {
+                if (high != IWL_RATE_INVALID && sr >= IWL_RATE_INCREASE_TH) {
+                        IWL_DEBUG_RATE(mvm,
+                                       "Good SR and no high rate measurement. "
+                                       "Increase rate\n");
+                        action = RS_ACTION_UPSCALE;
+                } else if (low != IWL_RATE_INVALID) {
+                        IWL_DEBUG_RATE(mvm,
+                                       "Remain in current rate\n");
+                        action = RS_ACTION_STAY;
+                }
+        }
+
+        /* Both adjacent throughputs are measured, but neither one has better
+         * throughput; we're using the best rate, don't change it!
+         */
+        else if ((low_tpt != IWL_INVALID_VALUE) &&
+                 (high_tpt != IWL_INVALID_VALUE) &&
+                 (low_tpt < current_tpt) &&
+                 (high_tpt < current_tpt)) {
+                IWL_DEBUG_RATE(mvm,
+                               "Both high and low are worse. "
+                               "Maintain rate\n");
+                action = RS_ACTION_STAY;
+        }
+
+        /* At least one adjacent rate's throughput is measured,
+         * and may have better performance.
+         */
+        else {
+                /* Higher adjacent rate's throughput is measured */
+                if (high_tpt != IWL_INVALID_VALUE) {
+                        /* Higher rate has better throughput */
+                        if (high_tpt > current_tpt &&
+                            sr >= IWL_RATE_INCREASE_TH) {
+                                IWL_DEBUG_RATE(mvm,
+                                               "Higher rate is better and good "
+                                               "SR. Increate rate\n");
+                                action = RS_ACTION_UPSCALE;
+                        } else {
+                                IWL_DEBUG_RATE(mvm,
+                                               "Higher rate isn't better OR "
+                                               "no good SR. Maintain rate\n");
+                                action = RS_ACTION_STAY;
+                        }
+
+                /* Lower adjacent rate's throughput is measured */
+                } else if (low_tpt != IWL_INVALID_VALUE) {
+                        /* Lower rate has better throughput */
+                        if (low_tpt > current_tpt) {
+                                IWL_DEBUG_RATE(mvm,
+                                               "Lower rate is better. "
+                                               "Decrease rate\n");
+                                action = RS_ACTION_DOWNSCALE;
+                        } else if (sr >= IWL_RATE_INCREASE_TH) {
+                                IWL_DEBUG_RATE(mvm,
+                                               "Lower rate isn't better and "
+                                               "good SR. Increase rate\n");
+                                action = RS_ACTION_UPSCALE;
+                        }
+                }
+        }
+
+        /* Sanity check; asked for decrease, but success rate or throughput
+         * has been good at old rate.  Don't change it.
+         */
+        if ((action == RS_ACTION_DOWNSCALE) && (low != IWL_RATE_INVALID) &&
+            ((sr > IWL_RATE_HIGH_TH) ||
+             (current_tpt > (100 * tbl->expected_tpt[low])))) {
+                IWL_DEBUG_RATE(mvm,
+                               "Sanity check failed. Maintain rate\n");
+                action = RS_ACTION_STAY;
+        }
+
+        return action;
+}
 
 /*
  * Do rate scaling and search for new modulation mode.
@@ -1636,7 +1733,7 @@ static void rs_rate_scale_perform(struct iwl_mvm *mvm,
         int low_tpt = IWL_INVALID_VALUE;
         int high_tpt = IWL_INVALID_VALUE;
         u32 fail_count;
-        s8 scale_action = 0;
+        enum rs_action scale_action = RS_ACTION_STAY;
         u16 rate_mask;
         u8 update_lq = 0;
         struct iwl_scale_tbl_info *tbl, *tbl1;
@@ -1830,85 +1927,8 @@ static void rs_rate_scale_perform(struct iwl_mvm *mvm,
                        rs_pretty_lq_type(rate->type), index, current_tpt, sr,
                        low, high, low_tpt, high_tpt);
 
-        scale_action = 0;
-
-        /* Too many failures, decrease rate */
-        if ((sr <= RS_SR_FORCE_DECREASE) || (current_tpt == 0)) {
-                IWL_DEBUG_RATE(mvm,
-                               "decrease rate because of low SR\n");
-                scale_action = -1;
-        /* No throughput measured yet for adjacent rates; try increase. */
-        } else if ((low_tpt == IWL_INVALID_VALUE) &&
-                   (high_tpt == IWL_INVALID_VALUE)) {
-                if (high != IWL_RATE_INVALID && sr >= IWL_RATE_INCREASE_TH) {
-                        IWL_DEBUG_RATE(mvm,
-                                       "Good SR and no high rate measurement. "
-                                       "Increase rate\n");
-                        scale_action = 1;
-                } else if (low != IWL_RATE_INVALID) {
-                        IWL_DEBUG_RATE(mvm,
-                                       "Remain in current rate\n");
-                        scale_action = 0;
-                }
-        }
-
-        /* Both adjacent throughputs are measured, but neither one has better
-         * throughput; we're using the best rate, don't change it! */
-        else if ((low_tpt != IWL_INVALID_VALUE) &&
-                 (high_tpt != IWL_INVALID_VALUE) &&
-                 (low_tpt < current_tpt) &&
-                 (high_tpt < current_tpt)) {
-                IWL_DEBUG_RATE(mvm,
-                               "Both high and low are worse. "
-                               "Maintain rate\n");
-                scale_action = 0;
-        }
-
-        /* At least one adjacent rate's throughput is measured,
-         * and may have better performance. */
-        else {
-                /* Higher adjacent rate's throughput is measured */
-                if (high_tpt != IWL_INVALID_VALUE) {
-                        /* Higher rate has better throughput */
-                        if (high_tpt > current_tpt &&
-                            sr >= IWL_RATE_INCREASE_TH) {
-                                IWL_DEBUG_RATE(mvm,
-                                               "Higher rate is better and good "
-                                               "SR. Increate rate\n");
-                                scale_action = 1;
-                        } else {
-                                IWL_DEBUG_RATE(mvm,
-                                               "Higher rate isn't better OR "
-                                               "no good SR. Maintain rate\n");
-                                scale_action = 0;
-                        }
-
-                /* Lower adjacent rate's throughput is measured */
-                } else if (low_tpt != IWL_INVALID_VALUE) {
-                        /* Lower rate has better throughput */
-                        if (low_tpt > current_tpt) {
-                                IWL_DEBUG_RATE(mvm,
-                                               "Lower rate is better. "
-                                               "Decrease rate\n");
-                                scale_action = -1;
-                        } else if (sr >= IWL_RATE_INCREASE_TH) {
-                                IWL_DEBUG_RATE(mvm,
-                                               "Lower rate isn't better and "
-                                               "good SR. Increase rate\n");
-                                scale_action = 1;
-                        }
-                }
-        }
-
-        /* Sanity check; asked for decrease, but success rate or throughput
-         * has been good at old rate.  Don't change it. */
-        if ((scale_action == -1) && (low != IWL_RATE_INVALID) &&
-            ((sr > IWL_RATE_HIGH_TH) ||
-             (current_tpt > (100 * tbl->expected_tpt[low])))) {
-                IWL_DEBUG_RATE(mvm,
-                               "Sanity check failed. Maintain rate\n");
-                scale_action = 0;
-        }
+        scale_action = rs_get_rate_action(mvm, tbl, sr, low, high,
+                                          current_tpt, low_tpt, high_tpt);
 
         /* Force a search in case BT doesn't like us being in MIMO */
         if (is_mimo(rate) &&
@@ -1920,7 +1940,7 @@ static void rs_rate_scale_perform(struct iwl_mvm *mvm,
         }
 
         switch (scale_action) {
-        case -1:
+        case RS_ACTION_DOWNSCALE:
                 /* Decrease starting rate, update uCode's rate table */
                 if (low != IWL_RATE_INVALID) {
                         update_lq = 1;
@@ -1931,7 +1951,7 @@ static void rs_rate_scale_perform(struct iwl_mvm *mvm,
                 }
 
                 break;
-        case 1:
+        case RS_ACTION_UPSCALE:
                 /* Increase starting rate, update uCode's rate table */
                 if (high != IWL_RATE_INVALID) {
                         update_lq = 1;
@@ -1942,7 +1962,7 @@ static void rs_rate_scale_perform(struct iwl_mvm *mvm,
                 }
 
                 break;
-        case 0:
+        case RS_ACTION_STAY:
                 /* No change */
         default:
                 break;