[Intel-gfx] [RFC 11/37] drm/i915/guc: Add a second client, to be used for preemption

[John.C.Harrison at Intel.com]

From: Dave Gordon <david.s.gordon at intel.com>

This second client is created with priority KMD_HIGH, and marked
as preemptive.

For: VIZ-2021
Signed-off-by: Dave Gordon <david.s.gordon at intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c        |  9 +++++++++
 drivers/gpu/drm/i915/i915_guc_submission.c | 15 ++++++++++++++-
 drivers/gpu/drm/i915/intel_guc.h           |  1 +
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index fefe73c..9e8f624 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2690,6 +2690,7 @@ static int i915_guc_info(struct seq_file *m, void *data)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_guc guc;
 	struct i915_guc_client client = {};
+	struct i915_guc_client preempt = {};
 	struct intel_engine_cs *ring;
 	enum intel_ring_id i;
 	u64 total = 0;
@@ -2705,6 +2706,11 @@ static int i915_guc_info(struct seq_file *m, void *data)
 		client = *guc.execbuf_client;
 		spin_unlock(&guc.execbuf_client->wq_lock);
 	}
+	if (guc.preempt_client) {
+		spin_lock(&guc.preempt_client->wq_lock);
+		preempt = *guc.preempt_client;
+		spin_unlock(&guc.preempt_client->wq_lock);
+	}
 	spin_unlock(&dev_priv->guc.host2guc_lock);
 
 	seq_printf(m, "GuC total action count: %llu\n", guc.action_count);
@@ -2725,6 +2731,9 @@ static int i915_guc_info(struct seq_file *m, void *data)
 	seq_printf(m, "\nGuC execbuf client @ %p:\n", guc.execbuf_client);
 	i915_guc_client_info(m, dev_priv, &client);
 
+	seq_printf(m, "\nGuC preempt client @ %p:\n", guc.preempt_client);
+	i915_guc_client_info(m, dev_priv, &preempt);
+
 	/* Add more as required ... */
 
 	return 0;
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index 55e10eb..d8fd644 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -395,6 +395,8 @@ static void guc_init_ctx_desc(struct intel_guc *guc,
 	memset(&desc, 0, sizeof(desc));
 
 	desc.attribute = GUC_CTX_DESC_ATTR_ACTIVE | GUC_CTX_DESC_ATTR_KERNEL;
+	if (client->priority <= GUC_CTX_PRIORITY_HIGH)
+		desc.attribute |= GUC_CTX_DESC_ATTR_PREEMPT;
 	desc.context_id = client->ctx_index;
 	desc.priority = client->priority;
 	desc.db_id = client->doorbell_id;
@@ -588,6 +590,9 @@ int i915_guc_submit(struct i915_guc_client *client,
 	unsigned long flags;
 	int q_ret, b_ret;
 
+	if (WARN_ON(ring_id >= I915_NUM_RINGS))
+		return -ENXIO;
+
 	/* Need this because of the deferred pin ctx and ring */
 	/* Shall we move this right after ring is pinned? */
 	lr_context_update(rq);
@@ -882,9 +887,15 @@ int i915_guc_submission_enable(struct drm_device *dev)
 		DRM_ERROR("Failed to create execbuf guc_client\n");
 		return -ENOMEM;
 	}
-
 	guc->execbuf_client = client;
 
+	/* 2nd client for preemptive submission */
+	client = guc_client_alloc(dev, GUC_CTX_PRIORITY_KMD_HIGH, ctx);
+	if (!client) {
+		DRM_ERROR("Failed to create preemptive guc_client\n");
+	}
+	guc->preempt_client = client;
+
 	host2guc_sample_forcewake(guc, client);
 
 	return 0;
@@ -895,6 +906,8 @@ void i915_guc_submission_disable(struct drm_device *dev)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_guc *guc = &dev_priv->guc;
 
+	guc_client_free(dev, guc->preempt_client);
+	guc->preempt_client = NULL;
 	guc_client_free(dev, guc->execbuf_client);
 	guc->execbuf_client = NULL;
 }
diff --git a/drivers/gpu/drm/i915/intel_guc.h b/drivers/gpu/drm/i915/intel_guc.h
index 386e79a..f56e0d9 100644
--- a/drivers/gpu/drm/i915/intel_guc.h
+++ b/drivers/gpu/drm/i915/intel_guc.h
@@ -94,6 +94,7 @@ struct intel_guc {
 	struct ida ctx_ids;
 
 	struct i915_guc_client *execbuf_client;
+	struct i915_guc_client *preempt_client;
 
 	spinlock_t host2guc_lock;	/* Protects all data below	*/
 
-- 
1.9.1