iwlwifi: mvm: rs: enable forcing single stream Tx decision

In certain testing scenarios we'd like to force a decision
between STBC/BFER/SISO. In the normal scenario this decision
is done by the FW. Enable this option vis debugfs.

Signed-off-by: Eyal Shapira <eyalx.shapira@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/mvm/fw-api-rs.h b/drivers/net/wireless/iwlwifi/mvm/fw-api-rs.h
index 4c33f27..0f1ea80 100644
--- a/drivers/net/wireless/iwlwifi/mvm/fw-api-rs.h
+++ b/drivers/net/wireless/iwlwifi/mvm/fw-api-rs.h
@@ -330,6 +330,14 @@
 #define LQ_SS_BFER_ALLOWED_POS		2
 #define LQ_SS_BFER_ALLOWED		(1 << LQ_SS_BFER_ALLOWED_POS)
 
+/* Bit 3: Force BFER or STBC for testing
+ * If this is set:
+ * If BFER is allowed then force the ucode to choose BFER else
+ * If STBC is allowed then force the ucode to choose STBC over SISO
+ */
+#define LQ_SS_FORCE_POS			3
+#define LQ_SS_FORCE			(1 << LQ_SS_FORCE_POS)
+
 /* Bit 31: ss_params field is valid. Used for FW backward compatibility
  * with other drivers which don't support the ss_params API yet
  */