drm/i915/guc: Allow user to control default GuC logging

While both naming and actual log enable logic in GuC interface are
confusing, we can simply expose the default log as yet another log
level.
GuC logic aside, from i915 point of view we now have the following GuC
log levels:
	0 Log disabled
	1 Non-verbose log
	2-5 Verbose log

v2: Adjust naming after rebase.
v3: Fixed the log_level logic error introduced on rebase.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180319095348.9716-10-michal.winiarski@intel.com

drivers/gpu/drm/i915/intel_guc.c

@@ -222,17 +222,23 @@ static u32 get_core_family(struct drm_i915_private *dev_priv)
 	}
 }
 
-static u32 get_log_verbosity_flags(void)
+static u32 get_log_control_flags(void)
 {
-	if (i915_modparams.guc_log_level > 0) {
-		u32 verbosity = i915_modparams.guc_log_level - 1;
+	u32 level = i915_modparams.guc_log_level;
+	u32 flags = 0;
 
-		GEM_BUG_ON(verbosity > GUC_LOG_VERBOSITY_MAX);
-		return verbosity << GUC_LOG_VERBOSITY_SHIFT;
-	}
+	GEM_BUG_ON(level < 0);
+
+	if (!GUC_LOG_LEVEL_TO_ENABLED(level))
+		flags |= GUC_LOG_DEFAULT_DISABLED;
+
+	if (!GUC_LOG_LEVEL_TO_VERBOSE(level))
+		flags |= GUC_LOG_DISABLED;
+	else
+		flags |= GUC_LOG_LEVEL_TO_VERBOSITY(level) <<
+			 GUC_LOG_VERBOSITY_SHIFT;
 
-	GEM_BUG_ON(i915_modparams.enable_guc < 0);
-	return GUC_LOG_DISABLED;
+	return flags;
 }
 
 /*
@@ -267,7 +273,7 @@ void intel_guc_init_params(struct intel_guc *guc)
 
 	params[GUC_CTL_LOG_PARAMS] = guc->log.flags;
 
-	params[GUC_CTL_DEBUG] = get_log_verbosity_flags();
+	params[GUC_CTL_DEBUG] = get_log_control_flags();
 
 	/* If GuC submission is enabled, set up additional parameters here */
 	if (USES_GUC_SUBMISSION(dev_priv)) {

drivers/gpu/drm/i915/intel_guc_fwif.h

@@ -127,7 +127,7 @@
 #define   GUC_PROFILE_ENABLED		(1 << 7)
 #define   GUC_WQ_TRACK_ENABLED		(1 << 8)
 #define   GUC_ADS_ENABLED		(1 << 9)
-#define   GUC_DEBUG_RESERVED		(1 << 10)
+#define   GUC_LOG_DEFAULT_DISABLED	(1 << 10)
 #define   GUC_ADS_ADDR_SHIFT		11
 #define   GUC_ADS_ADDR_MASK		0xfffff800
 
@@ -539,7 +539,8 @@ union guc_log_control {
 		u32 logging_enabled:1;
 		u32 reserved1:3;
 		u32 verbosity:4;
-		u32 reserved2:24;
+		u32 default_logging:1;
+		u32 reserved2:23;
 	};
 	u32 value;
 } __packed;

drivers/gpu/drm/i915/intel_guc_log.c

@@ -57,12 +57,14 @@ 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, bool enable, u32 verbosity)
+static int guc_log_control(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[] = {
@@ -499,13 +501,6 @@ int intel_guc_log_level_get(struct intel_guc_log *log)
 	return i915_modparams.guc_log_level;
 }
 
-#define GUC_LOG_LEVEL_DISABLED		0
-#define LOG_LEVEL_TO_ENABLED(x)		((x) > 0)
-#define LOG_LEVEL_TO_VERBOSITY(x) ({		\
-	typeof(x) _x = (x);			\
-	LOG_LEVEL_TO_ENABLED(_x) ? _x - 1 : 0;	\
-})
-#define VERBOSITY_TO_LOG_LEVEL(x)  ((x) + 1)
 int intel_guc_log_level_set(struct intel_guc_log *log, u64 val)
 {
 	struct intel_guc *guc = log_to_guc(log);
@@ -521,7 +516,7 @@ int intel_guc_log_level_set(struct intel_guc_log *log, u64 val)
 	 * as indication that logging should be disabled.
 	 */
 	if (val < GUC_LOG_LEVEL_DISABLED ||
-	    val > VERBOSITY_TO_LOG_LEVEL(GUC_LOG_VERBOSITY_MAX))
+	    val > GUC_VERBOSITY_TO_LOG_LEVEL(GUC_LOG_VERBOSITY_MAX))
 		return -EINVAL;
 
 	mutex_lock(&dev_priv->drm.struct_mutex);
@@ -532,8 +527,9 @@ int intel_guc_log_level_set(struct intel_guc_log *log, u64 val)
 	}
 
 	intel_runtime_pm_get(dev_priv);
-	ret = guc_log_control(guc, LOG_LEVEL_TO_ENABLED(val),
-			      LOG_LEVEL_TO_VERBOSITY(val));
+	ret = guc_log_control(guc, GUC_LOG_LEVEL_TO_VERBOSE(val),
+			      GUC_LOG_LEVEL_TO_ENABLED(val),
+			      GUC_LOG_LEVEL_TO_VERBOSITY(val));
 	intel_runtime_pm_put(dev_priv);
 	if (ret) {
 		DRM_DEBUG_DRIVER("guc_log_control action failed %d\n", ret);

drivers/gpu/drm/i915/intel_guc_log.h

@@ -40,6 +40,21 @@ struct intel_guc;
 #define GUC_LOG_SIZE	((1 + GUC_LOG_DPC_PAGES + 1 + GUC_LOG_ISR_PAGES + \
 			  1 + GUC_LOG_CRASH_PAGES + 1) << PAGE_SHIFT)
 
+/*
+ * While we're using plain log level in i915, GuC controls are much more...
+ * "elaborate"? We have a couple of bits for verbosity, separate bit for actual
+ * log enabling, and separate bit for default logging - which "conveniently"
+ * ignores the enable bit.
+ */
+#define GUC_LOG_LEVEL_DISABLED			0
+#define GUC_LOG_LEVEL_TO_ENABLED(x)		((x) > 0)
+#define GUC_LOG_LEVEL_TO_VERBOSE(x)		((x) > 1)
+#define GUC_LOG_LEVEL_TO_VERBOSITY(x) ({		\
+	typeof(x) _x = (x);				\
+	GUC_LOG_LEVEL_TO_VERBOSE(_x) ? _x - 2 : 0;	\
+})
+#define GUC_VERBOSITY_TO_LOG_LEVEL(x)		((x) + 2)
+
 struct intel_guc_log {
 	u32 flags;
 	struct i915_vma *vma;

drivers/gpu/drm/i915/intel_uc.c

@@ -75,7 +75,8 @@ static int __get_default_guc_log_level(struct drm_i915_private *dev_priv)
 	if (HAS_GUC(dev_priv) && intel_uc_is_using_guc() &&
 	    (IS_ENABLED(CONFIG_DRM_I915_DEBUG) ||
 	     IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)))
-		guc_log_level = 1 + GUC_LOG_VERBOSITY_MAX;
+		guc_log_level =
+			GUC_VERBOSITY_TO_LOG_LEVEL(GUC_LOG_VERBOSITY_MAX);
 
 	/* Any platform specific fine-tuning can be done here */
 
@@ -142,17 +143,20 @@ static void sanitize_options_early(struct drm_i915_private *dev_priv)
 		i915_modparams.guc_log_level = 0;
 	}
 
-	if (i915_modparams.guc_log_level > 1 + GUC_LOG_VERBOSITY_MAX) {
+	if (i915_modparams.guc_log_level >
+	    GUC_VERBOSITY_TO_LOG_LEVEL(GUC_LOG_VERBOSITY_MAX)) {
 		DRM_WARN("Incompatible option detected: %s=%d, %s!\n",
 			 "guc_log_level", i915_modparams.guc_log_level,
 			 "verbosity too high");
-		i915_modparams.guc_log_level = 1 + GUC_LOG_VERBOSITY_MAX;
+		i915_modparams.guc_log_level =
+			GUC_VERBOSITY_TO_LOG_LEVEL(GUC_LOG_VERBOSITY_MAX);
 	}
 
-	DRM_DEBUG_DRIVER("guc_log_level=%d (enabled:%s verbosity:%d)\n",
+	DRM_DEBUG_DRIVER("guc_log_level=%d (enabled:%s, verbose:%s, verbosity:%d)\n",
 			 i915_modparams.guc_log_level,
 			 yesno(i915_modparams.guc_log_level),
-			 i915_modparams.guc_log_level - 1);
+			 yesno(GUC_LOG_LEVEL_TO_VERBOSE(i915_modparams.guc_log_level)),
+			 GUC_LOG_LEVEL_TO_VERBOSITY(i915_modparams.guc_log_level));
 
 	/* Make sure that sanitization was done */
 	GEM_BUG_ON(i915_modparams.enable_guc < 0);