iwlwifi: mvm: don't use SAR Geo if basic SAR is not used

We can't use SAR Geo if basic SAR is not enabled, since the SAR Geo
tables define offsets in relation to the basic SAR table in use.

To fix this, make iwl_mvm_sar_init() return one in case WRDS is not
available, so we can skip reading WGDS entirely.

Fixes: a6bff3cb ("iwlwifi: mvm: add GEO_TX_POWER_LIMIT cmd for geographic tx power table")
Cc: stable@vger.kernel.org # 4.12+
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/fw.c

@@ -928,6 +928,11 @@ static int iwl_mvm_sar_get_ewrd_table(struct iwl_mvm *mvm)
 	return -ENOENT;
 }
 
+static int iwl_mvm_sar_get_wgds_table(struct iwl_mvm *mvm)
+{
+	return -ENOENT;
+}
+
 static int iwl_mvm_sar_geo_init(struct iwl_mvm *mvm)
 {
 	return 0;
@@ -954,8 +959,11 @@ static int iwl_mvm_sar_init(struct iwl_mvm *mvm)
 		IWL_DEBUG_RADIO(mvm,
 				"WRDS SAR BIOS table invalid or unavailable. (%d)\n",
 				ret);
-		/* if not available, don't fail and don't bother with EWRD */
-		return 0;
+		/*
+		 * If not available, don't fail and don't bother with EWRD.
+		 * Return 1 to tell that we can't use WGDS either.
+		 */
+		return 1;
 	}
 
 	ret = iwl_mvm_sar_get_ewrd_table(mvm);
@@ -968,9 +976,13 @@ static int iwl_mvm_sar_init(struct iwl_mvm *mvm)
 	/* choose profile 1 (WRDS) as default for both chains */
 	ret = iwl_mvm_sar_select_profile(mvm, 1, 1);
 
-	/* if we don't have profile 0 from BIOS, just skip it */
+	/*
+	 * If we don't have profile 0 from BIOS, just skip it.  This
+	 * means that SAR Geo will not be enabled either, even if we
+	 * have other valid profiles.
+	 */
 	if (ret == -ENOENT)
-		return 0;
+		return 1;
 
 	return ret;
 }
@@ -1168,11 +1180,19 @@ int iwl_mvm_up(struct iwl_mvm *mvm)
 		iwl_mvm_unref(mvm, IWL_MVM_REF_UCODE_DOWN);
 
 	ret = iwl_mvm_sar_init(mvm);
-	if (ret)
-		goto error;
+	if (ret == 0) {
+		ret = iwl_mvm_sar_geo_init(mvm);
+	} else if (ret > 0 && !iwl_mvm_sar_get_wgds_table(mvm)) {
+		/*
+		 * If basic SAR is not available, we check for WGDS,
+		 * which should *not* be available either.  If it is
+		 * available, issue an error, because we can't use SAR
+		 * Geo without basic SAR.
+		 */
+		IWL_ERR(mvm, "BIOS contains WGDS but no WRDS\n");
+	}
 
-	ret = iwl_mvm_sar_geo_init(mvm);
-	if (ret)
+	if (ret < 0)
 		goto error;
 
 	iwl_mvm_leds_sync(mvm);