drm/i915/guc: Change values for i915_guc_log_control

Today we have format mismatch between read/write operations
of i915_guc_log_control entry. For read we return (0, 1..4)
that represents disable/verbosity levels, but for write we
force user to follow internal structure format (0,1,9,11,13).
Let's hide internals from the user and accept same values
as we support for read and related guc_log_level modparam.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180111152441.21676-2-michal.wajdeczko@intel.com
Reviewed-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/intel_guc_log.c

@@ -58,11 +58,15 @@ static int guc_log_flush(struct intel_guc *guc)
 	return intel_guc_send(guc, action, ARRAY_SIZE(action));
 }
 
-static int guc_log_control(struct intel_guc *guc, u32 control_val)
+static int guc_log_control(struct intel_guc *guc, bool enable, u32 verbosity)
 {
+	union guc_log_control control_val = {
+		.logging_enabled = enable,
+		.verbosity = verbosity,
+	};
 	u32 action[] = {
 		INTEL_GUC_ACTION_UK_LOG_ENABLE_LOGGING,
-		control_val
+		control_val.value
 	};
 
 	return intel_guc_send(guc, action, ARRAY_SIZE(action));
@@ -567,28 +571,27 @@ void intel_guc_log_destroy(struct intel_guc *guc)
 int i915_guc_log_control(struct drm_i915_private *dev_priv, u64 control_val)
 {
 	struct intel_guc *guc = &dev_priv->guc;
-
-	union guc_log_control log_param;
+	bool enable_logging = control_val > 0;
+	u32 verbosity;
 	int ret;
 
-	log_param.value = control_val;
-
-	if (log_param.verbosity < GUC_LOG_VERBOSITY_MIN ||
-	    log_param.verbosity > GUC_LOG_VERBOSITY_MAX)
+	BUILD_BUG_ON(GUC_LOG_VERBOSITY_MIN);
+	if (control_val > 1 + GUC_LOG_VERBOSITY_MAX)
 		return -EINVAL;
 
 	/* This combination doesn't make sense & won't have any effect */
-	if (!log_param.logging_enabled && !i915_modparams.guc_log_level)
+	if (!enable_logging && !i915_modparams.guc_log_level)
 		return 0;
 
-	ret = guc_log_control(guc, log_param.value);
+	verbosity = enable_logging ? control_val - 1 : 0;
+	ret = guc_log_control(guc, enable_logging, verbosity);
 	if (ret < 0) {
 		DRM_DEBUG_DRIVER("guc_logging_control action failed %d\n", ret);
 		return ret;
 	}
 
-	if (log_param.logging_enabled) {
-		i915_modparams.guc_log_level = 1 + log_param.verbosity;
+	if (enable_logging) {
+		i915_modparams.guc_log_level = 1 + verbosity;
 
 		/*
 		 * If log was disabled at boot time, then the relay channel file