drm/i915/guc: Keep GuC interrupts enabled when using GuC

The GuC log contains a separate space used for crash dump.
We even get a separate notification for it. While we're not handling
crash differently yet, it makes sense to decouple the two right now to
simplify the following patches.

v2: Move guc_log_flush_irq_disable up to avoid movement in following
    patches (Sagar).
v3: s/guc_log_flush_irq_*/guc_flush_log_msg_*, rebase after mass rename

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> (v2)
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/20180319095348.9716-1-michal.winiarski@intel.com

drivers/gpu/drm/i915/intel_guc.c

@@ -67,6 +67,7 @@ void intel_guc_init_early(struct intel_guc *guc)
 	intel_guc_log_init_early(&guc->log);
 
 	mutex_init(&guc->send_mutex);
+	spin_lock_init(&guc->irq_lock);
 	guc->send = intel_guc_send_nop;
 	guc->notify = gen8_guc_raise_irq;
 }
@@ -368,7 +369,7 @@ int intel_guc_send_mmio(struct intel_guc *guc, const u32 *action, u32 len)
 void intel_guc_to_host_event_handler(struct intel_guc *guc)
 {
 	struct drm_i915_private *dev_priv = guc_to_i915(guc);
-	u32 msg, flush;
+	u32 msg, val;
 
 	/*
 	 * Sample the log buffer flush related bits & clear them out now
@@ -381,24 +382,18 @@ void intel_guc_to_host_event_handler(struct intel_guc *guc)
 	 * could happen that GuC sets the bit for 2nd interrupt but Host
 	 * clears out the bit on handling the 1st interrupt.
 	 */
-
-	msg = I915_READ(SOFT_SCRATCH(15));
-	flush = msg & (INTEL_GUC_RECV_MSG_CRASH_DUMP_POSTED |
-		       INTEL_GUC_RECV_MSG_FLUSH_LOG_BUFFER);
-	if (flush) {
-		/* Clear the message bits that are handled */
-		I915_WRITE(SOFT_SCRATCH(15), msg & ~flush);
-
-		/* Handle flush interrupt in bottom half */
+	spin_lock(&guc->irq_lock);
+	val = I915_READ(SOFT_SCRATCH(15));
+	msg = val & guc->msg_enabled_mask;
+	I915_WRITE(SOFT_SCRATCH(15), val & ~msg);
+	spin_unlock(&guc->irq_lock);
+
+	if (msg & (INTEL_GUC_RECV_MSG_FLUSH_LOG_BUFFER |
+		   INTEL_GUC_RECV_MSG_CRASH_DUMP_POSTED)) {
 		queue_work(guc->log.runtime.flush_wq,
 			   &guc->log.runtime.flush_work);
 
 		guc->log.flush_interrupt_count++;
-	} else {
-		/*
-		 * Not clearing of unhandled event bits won't result in
-		 * re-triggering of the interrupt.
-		 */
 	}
 }
 

drivers/gpu/drm/i915/intel_guc.h

@@ -56,7 +56,9 @@ struct intel_guc {
 	struct drm_i915_gem_object *load_err_log;
 
 	/* intel_guc_recv interrupt related state */
+	spinlock_t irq_lock;
 	bool interrupts_enabled;
+	unsigned int msg_enabled_mask;
 
 	struct i915_vma *ads_vma;
 	struct i915_vma *stage_desc_pool;

drivers/gpu/drm/i915/intel_guc_log.c

@@ -73,6 +73,22 @@ static int guc_log_control(struct intel_guc *guc, bool enable, u32 verbosity)
 	return intel_guc_send(guc, action, ARRAY_SIZE(action));
 }
 
+static void guc_flush_log_msg_enable(struct intel_guc *guc)
+{
+	spin_lock_irq(&guc->irq_lock);
+	guc->msg_enabled_mask |= INTEL_GUC_RECV_MSG_FLUSH_LOG_BUFFER |
+				 INTEL_GUC_RECV_MSG_CRASH_DUMP_POSTED;
+	spin_unlock_irq(&guc->irq_lock);
+}
+
+static void guc_flush_log_msg_disable(struct intel_guc *guc)
+{
+	spin_lock_irq(&guc->irq_lock);
+	guc->msg_enabled_mask &= ~(INTEL_GUC_RECV_MSG_FLUSH_LOG_BUFFER |
+				   INTEL_GUC_RECV_MSG_CRASH_DUMP_POSTED);
+	spin_unlock_irq(&guc->irq_lock);
+}
+
 static inline struct intel_guc *log_to_guc(struct intel_guc_log *log)
 {
 	return container_of(log, struct intel_guc, log);
@@ -709,12 +725,7 @@ int intel_guc_log_register(struct intel_guc_log *log)
 	if (ret)
 		goto err_runtime;
 
-	/* GuC logging is currently the only user of Guc2Host interrupts */
-	mutex_lock(&i915->drm.struct_mutex);
-	intel_runtime_pm_get(i915);
-	gen9_enable_guc_interrupts(i915);
-	intel_runtime_pm_put(i915);
-	mutex_unlock(&i915->drm.struct_mutex);
+	guc_flush_log_msg_enable(guc);
 
 	return 0;
 
@@ -733,6 +744,8 @@ void intel_guc_log_unregister(struct intel_guc_log *log)
 	struct intel_guc *guc = log_to_guc(log);
 	struct drm_i915_private *i915 = guc_to_i915(guc);
 
+	guc_flush_log_msg_disable(guc);
+
 	/*
 	 * Once logging is disabled, GuC won't generate logs & send an
 	 * interrupt. But there could be some data in the log buffer
@@ -742,12 +755,6 @@ void intel_guc_log_unregister(struct intel_guc_log *log)
 	guc_flush_logs(log);
 
 	mutex_lock(&i915->drm.struct_mutex);
-
-	/* GuC logging is currently the only user of Guc2Host interrupts */
-	intel_runtime_pm_get(i915);
-	gen9_disable_guc_interrupts(i915);
-	intel_runtime_pm_put(i915);
-
 	guc_log_runtime_destroy(log);
 	mutex_unlock(&i915->drm.struct_mutex);
 

drivers/gpu/drm/i915/intel_uc.c

@@ -247,6 +247,8 @@ static int guc_enable_communication(struct intel_guc *guc)
 {
 	struct drm_i915_private *dev_priv = guc_to_i915(guc);
 
+	gen9_enable_guc_interrupts(dev_priv);
+
 	if (HAS_GUC_CT(dev_priv))
 		return intel_guc_enable_ct(guc);
 
@@ -261,6 +263,8 @@ static void guc_disable_communication(struct intel_guc *guc)
 	if (HAS_GUC_CT(dev_priv))
 		intel_guc_disable_ct(guc);
 
+	gen9_disable_guc_interrupts(dev_priv);
+
 	guc->send = intel_guc_send_nop;
 }
 
@@ -413,12 +417,9 @@ int intel_uc_init_hw(struct drm_i915_private *dev_priv)
 	}
 
 	if (USES_GUC_SUBMISSION(dev_priv)) {
-		if (i915_modparams.guc_log_level)
-			gen9_enable_guc_interrupts(dev_priv);
-
 		ret = intel_guc_submission_enable(guc);
 		if (ret)
-			goto err_interrupts;
+			goto err_communication;
 	}
 
 	dev_info(dev_priv->drm.dev, "GuC firmware version %u.%u\n",
@@ -433,8 +434,6 @@ int intel_uc_init_hw(struct drm_i915_private *dev_priv)
 	/*
 	 * We've failed to load the firmware :(
 	 */
-err_interrupts:
-	gen9_disable_guc_interrupts(dev_priv);
 err_communication:
 	guc_disable_communication(guc);
 err_log_capture:
@@ -464,9 +463,6 @@ void intel_uc_fini_hw(struct drm_i915_private *dev_priv)
 		intel_guc_submission_disable(guc);
 
 	guc_disable_communication(guc);
-
-	if (USES_GUC_SUBMISSION(dev_priv))
-		gen9_disable_guc_interrupts(dev_priv);
 }
 
 int intel_uc_suspend(struct drm_i915_private *i915)