iwlwifi: mvm: correct skip-over-DTIM implementation

The formula used in D0i3 should also be used in D3, instead of
the hardcoded value.

Additionally, the formula is actually wrong - if the calculation
yields 0 then 1 should be used instead of disabling entirely.
Also need to add 1 since the firmware needs 3 to skip 2, etc.

To make all this clearer, centralize the calculation into a
single function.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

diff --git a/drivers/net/wireless/iwlwifi/mvm/power.c b/drivers/net/wireless/iwlwifi/mvm/power.c
index 4645877..21a858d 100644 (file)
--- a/drivers/net/wireless/iwlwifi/mvm/power.c
+++ b/drivers/net/wireless/iwlwifi/mvm/power.c
@@ -7,6 +7,7 @@
  *
  * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
  * Copyright(c) 2013 - 2014 Intel Mobile Communications GmbH
+ * Copyright(c) 2015        Intel Deutschland GmbH
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of version 2 of the GNU General Public License as
@@ -33,6 +34,7 @@
  *
  * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
  * Copyright(c) 2013 - 2014 Intel Mobile Communications GmbH
+ * Copyright(c) 2015        Intel Deutschland GmbH
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -306,13 +308,50 @@ static bool iwl_mvm_power_is_radar(struct ieee80211_vif *vif)
        return radar_detect;
 }
 
+static void iwl_mvm_power_config_skip_dtim(struct iwl_mvm *mvm,
+                                          struct ieee80211_vif *vif,
+                                          struct iwl_mac_power_cmd *cmd,
+                                          bool host_awake)
+{
+       int dtimper = vif->bss_conf.dtim_period ?: 1;
+       int skip;
+
+       /* disable, in case we're supposed to override */
+       cmd->skip_dtim_periods = 0;
+       cmd->flags &= ~cpu_to_le16(POWER_FLAGS_SKIP_OVER_DTIM_MSK);
+
+       if (iwl_mvm_power_is_radar(vif))
+               return;
+
+       if (dtimper >= 10)
+               return;
+
+       /* TODO: check that multicast wake lock is off */
+
+       if (host_awake) {
+               if (iwlmvm_mod_params.power_scheme != IWL_POWER_SCHEME_LP)
+                       return;
+               skip = 2;
+       } else {
+               int dtimper_tu = dtimper * vif->bss_conf.beacon_int;
+
+               if (WARN_ON(!dtimper_tu))
+                       return;
+               /* configure skip over dtim up to 306TU - 314 msec */
+               skip = max_t(u8, 1, 306 / dtimper_tu);
+       }
+
+       /* the firmware really expects "look at every X DTIMs", so add 1 */
+       cmd->skip_dtim_periods = 1 + skip;
+       cmd->flags |= cpu_to_le16(POWER_FLAGS_SKIP_OVER_DTIM_MSK);
+}
+
 static void iwl_mvm_power_build_cmd(struct iwl_mvm *mvm,
                                    struct ieee80211_vif *vif,
                                    struct iwl_mac_power_cmd *cmd)
 {
        int dtimper, bi;
        int keep_alive;
-       bool radar_detect = false;
        struct iwl_mvm_vif *mvmvif __maybe_unused =
                iwl_mvm_vif_from_mac80211(vif);
 
@@ -350,16 +389,8 @@ static void iwl_mvm_power_build_cmd(struct iwl_mvm *mvm,
                cmd->lprx_rssi_threshold = POWER_LPRX_RSSI_THRESHOLD;
        }
 
-       /* Check if radar detection is required on current channel */
-       radar_detect = iwl_mvm_power_is_radar(vif);
-
-       /* Check skip over DTIM conditions */
-       if (!radar_detect && (dtimper < 10) &&
-           (iwlmvm_mod_params.power_scheme == IWL_POWER_SCHEME_LP ||
-            mvm->cur_ucode == IWL_UCODE_WOWLAN)) {
-               cmd->flags |= cpu_to_le16(POWER_FLAGS_SKIP_OVER_DTIM_MSK);
-               cmd->skip_dtim_periods = 3;
-       }
+       iwl_mvm_power_config_skip_dtim(mvm, vif, cmd,
+                                      mvm->cur_ucode != IWL_UCODE_WOWLAN);
 
        if (mvm->cur_ucode != IWL_UCODE_WOWLAN) {
                cmd->rx_data_timeout =
@@ -964,24 +995,11 @@ int iwl_mvm_update_d0i3_power_mode(struct iwl_mvm *mvm,
                return 0;
 
        iwl_mvm_power_build_cmd(mvm, vif, &cmd);
-       if (enable) {
-               /* configure skip over dtim up to 306TU - 314 msec */
-               int dtimper = vif->bss_conf.dtim_period ?: 1;
-               int dtimper_tu = dtimper * vif->bss_conf.beacon_int;
-               bool radar_detect = iwl_mvm_power_is_radar(vif);
 
-               if (WARN_ON(!dtimper_tu))
-                       return 0;
-
-               /* Check skip over DTIM conditions */
-               /* TODO: check that multicast wake lock is off */
-               if (!radar_detect && (dtimper < 10)) {
-                       cmd.skip_dtim_periods = 306 / dtimper_tu;
-                       if (cmd.skip_dtim_periods)
-                               cmd.flags |= cpu_to_le16(
-                                       POWER_FLAGS_SKIP_OVER_DTIM_MSK);
-               }
-       }
+       /* when enabling D0i3, override the skip-over-dtim configuration */
+       if (enable)
+               iwl_mvm_power_config_skip_dtim(mvm, vif, &cmd, false);
+
        iwl_mvm_power_log(mvm, &cmd);
 #ifdef CONFIG_IWLWIFI_DEBUGFS
        memcpy(&mvmvif->mac_pwr_cmd, &cmd, sizeof(cmd));