drm/i915/guc: Drop union guc_log_control

Usually we use shift/mask macros for bit field definitions.
Union guc_log_control was not following that pattern.

Additional bonus:

add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-25 (-25)
Function                                     old     new   delta
intel_guc_log_level_set                      388     363     -25

v2: prevent out-of-range verbosity (MichalWi)
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Reviewed-by: MichaĹ Winiarski <michal.winiarski@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180320181419.35576-2-michal.wajdeczko@intel.com

drivers/gpu/drm/i915/intel_guc_fwif.h

@@ -534,17 +534,6 @@ struct guc_log_buffer_state {
 	u32 version;
 } __packed;
 
-union guc_log_control {
-	struct {
-		u32 logging_enabled:1;
-		u32 reserved1:3;
-		u32 verbosity:4;
-		u32 default_logging:1;
-		u32 reserved2:23;
-	};
-	u32 value;
-} __packed;
-
 struct guc_ctx_report {
 	u32 report_return_status;
 	u32 reserved1[64];
@@ -603,6 +592,11 @@ enum intel_guc_report_status {
 	INTEL_GUC_REPORT_STATUS_COMPLETE = 0x4,
 };
 
+#define GUC_LOG_CONTROL_LOGGING_ENABLED	(1 << 0)
+#define GUC_LOG_CONTROL_VERBOSITY_SHIFT	4
+#define GUC_LOG_CONTROL_VERBOSITY_MASK	(0xF << GUC_LOG_CONTROL_VERBOSITY_SHIFT)
+#define GUC_LOG_CONTROL_DEFAULT_LOGGING	(1 << 8)
+
 /*
  * The GuC sends its response to a command by overwriting the
  * command in SS0. The response is distinguishable from a command

drivers/gpu/drm/i915/intel_guc_log.c

@@ -60,18 +60,15 @@ static int guc_action_flush_log(struct intel_guc *guc)
 static int guc_action_control_log(struct intel_guc *guc, bool enable,
 				  bool default_logging, u32 verbosity)
 {
-	union guc_log_control control_val = {
-		{
-			.logging_enabled = enable,
-			.verbosity = verbosity,
-			.default_logging = default_logging,
-		},
-	};
 	u32 action[] = {
 		INTEL_GUC_ACTION_UK_LOG_ENABLE_LOGGING,
-		control_val.value
+		(enable ? GUC_LOG_CONTROL_LOGGING_ENABLED : 0) |
+		(verbosity << GUC_LOG_CONTROL_VERBOSITY_SHIFT) |
+		(default_logging ? GUC_LOG_CONTROL_DEFAULT_LOGGING : 0)
 	};
 
+	GEM_BUG_ON(verbosity > GUC_LOG_VERBOSITY_MAX);
+
 	return intel_guc_send(guc, action, ARRAY_SIZE(action));
 }