[PATCH 14/18] drm/i915: Support for forceful flush of GuC log buffer

[akash.goel@intel.com]

From: Sagar Arun Kamble <sagar.a.kamble@intel.com>

GuC firmware sends a flush interrupt to Host when the log buffer is half
full and at that time only it updates the log buffer state.
But in certain cases, as described below, it could be useful to have all
that even when log buffer is only partially full. For that there is a force
log buffer flush Host2GuC action supported by GuC firmware.

For Validation requirements, a forceful flush is needed to collect the
left over logs on disabling logging. The same can be done before proceeding
with GPU/GuC reset as there could be some data in log buffer which is yet
to be captured and those logs would be particularly useful to understand
that why the reset was initiated.

Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: Akash Goel <akash.goel@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_guc_submission.c | 30 ++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_guc.h           |  1 +
 2 files changed, 31 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index ae52d10..b8f6baf 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -183,6 +183,16 @@ static int host2guc_logbuffer_flush_complete(struct intel_guc *guc)
 	return host2guc_action(guc, data, 1);
 }
 
+static int host2guc_force_logbuffer_flush(struct intel_guc *guc)
+{
+	u32 data[2];
+
+	data[0] = HOST2GUC_ACTION_FORCE_LOG_BUFFER_FLUSH;
+	data[1] = 0;
+
+	return host2guc_action(guc, data, 2);
+}
+
 /*
  * Initialise, update, or clear doorbell data shared with the GuC
  *
@@ -1523,6 +1533,26 @@ void i915_guc_capture_logs(struct drm_i915_private *dev_priv)
 	intel_runtime_pm_put(dev_priv);
 }
 
+void i915_guc_flush_logs(struct drm_i915_private *dev_priv)
+{
+	if (!i915.enable_guc_submission || (i915.guc_log_level < 0))
+		return;
+
+	/* First disable the interrupts, will be renabled afterwards */
+	gen9_disable_guc_interrupts(dev_priv);
+
+	/* Before initiating the forceful flush, wait for any pending/ongoing
+	 * flush to complete otherwise forceful flush may not actually happen.
+	 */
+	flush_work(&dev_priv->guc.log.flush_work);
+
+	/* Ask GuC to update the log buffer state */
+	host2guc_force_logbuffer_flush(&dev_priv->guc);
+
+	/* GuC would have updated log buffer by now, so capture it */
+	i915_guc_capture_logs(dev_priv);
+}
+
 void i915_guc_unregister(struct drm_i915_private *dev_priv)
 {
 	if (!i915.enable_guc_submission)
diff --git a/drivers/gpu/drm/i915/intel_guc.h b/drivers/gpu/drm/i915/intel_guc.h
index 8598f38..d918241 100644
--- a/drivers/gpu/drm/i915/intel_guc.h
+++ b/drivers/gpu/drm/i915/intel_guc.h
@@ -182,6 +182,7 @@ int i915_guc_wq_check_space(struct drm_i915_gem_request *rq);
 void i915_guc_submission_disable(struct drm_i915_private *dev_priv);
 void i915_guc_submission_fini(struct drm_i915_private *dev_priv);
 void i915_guc_capture_logs(struct drm_i915_private *dev_priv);
+void i915_guc_flush_logs(struct drm_i915_private *dev_priv);
 void i915_guc_register(struct drm_i915_private *dev_priv);
 void i915_guc_unregister(struct drm_i915_private *dev_priv);
 
-- 
1.9.2

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