From e12ab16907252ebc3ec956932eb40ed88105346b Mon Sep 17 00:00:00 2001

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

Date: Thu, 26 Oct 2017 16:17:37 +0200

Subject: [PATCH] drm/i915/guc: Add a second client, to be used for preemption

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Git-commit: e12ab16907252ebc3ec956932eb40ed88105346b

Patch-mainline: v4.16-rc1

References: FATE#322643 bsc#1055900

This second client is created with priority KMD_HIGH, and marked

as preemptive. This will allow us to request preemption using GuC actions.

V2: Extract clients creation into a helper, debugfs fixups. (Michał)

Recreate doorbell on init. (Daniele)

Move clients into an array.

V3: And move clients back from an array, to get rid of the enum (Michał)

V4: Use is_high_priority, move DRM_ERROR into __create_doorbell, move

GEM_BUG_ON inside guc_clients_create (Michał)

V5: Split the BUG_ON (Michał)

V6: Cleanup after error during doorbell reinit (Michał)

Signed-off-by: Dave Gordon <david.s.gordon@intel.com>

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: Jeff McGee <jeff.mcgee@intel.com>

Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>

Cc: Oscar Mateo <oscar.mateo@intel.com>

Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

Link: https://patchwork.freedesktop.org/patch/msgid/20171026141737.31656-1-michal.winiarski@intel.com

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/gpu/drm/i915/i915_debugfs.c        |    2 

 drivers/gpu/drm/i915/i915_guc_submission.c |  118 ++++++++++++++++++++---------

 drivers/gpu/drm/i915/intel_guc.h           |    1 

 3 files changed, 86 insertions(+), 35 deletions(-)

--- a/drivers/gpu/drm/i915/i915_debugfs.c

+++ b/drivers/gpu/drm/i915/i915_debugfs.c

@@ -2430,6 +2430,8 @@ static int i915_guc_info(struct seq_file

 	seq_printf(m, "\nGuC execbuf client @ %p:\n", guc->execbuf_client);

 	i915_guc_client_info(m, dev_priv, guc->execbuf_client);

+	seq_printf(m, "\nGuC preempt client @ %p:\n", guc->preempt_client);

+	i915_guc_client_info(m, dev_priv, guc->preempt_client);

 	i915_guc_log_info(m, dev_priv);

--- a/drivers/gpu/drm/i915/i915_guc_submission.c

+++ b/drivers/gpu/drm/i915/i915_guc_submission.c

@@ -33,10 +33,11 @@

  *

  * GuC client:

  * A i915_guc_client refers to a submission path through GuC. Currently, there

- * is only one of these (the execbuf_client) and this one is charged with all

- * submissions to the GuC. This struct is the owner of a doorbell, a process

- * descriptor and a workqueue (all of them inside a single gem object that

- * contains all required pages for these elements).

+ * are two clients. One of them (the execbuf_client) is charged with all

+ * submissions to the GuC, the other one (preempt_client) is responsible for

+ * preempting the execbuf_client. This struct is the owner of a doorbell, a

+ * process descriptor and a workqueue (all of them inside a single gem object

+ * that contains all required pages for these elements).

  *

  * GuC stage descriptor:

  * During initialization, the driver allocates a static pool of 1024 such

@@ -83,7 +84,8 @@

 static inline bool is_high_priority(struct i915_guc_client* client)

 {

-	return client->priority <= GUC_CLIENT_PRIORITY_HIGH;

+	return (client->priority == GUC_CLIENT_PRIORITY_KMD_HIGH ||

+		client->priority == GUC_CLIENT_PRIORITY_HIGH);

 }

 static int __reserve_doorbell(struct i915_guc_client *client)

@@ -196,8 +198,11 @@ static int __create_doorbell(struct i915

 	doorbell->cookie = 0;

 	err = __guc_allocate_doorbell(client->guc, client->stage_id);

-	if (err)

+	if (err) {

 		doorbell->db_status = GUC_DOORBELL_DISABLED;

+		DRM_ERROR("Couldn't create client %u doorbell: %d\n",

+			  client->stage_id, err);

+	}

 	return err;

 }

@@ -363,6 +368,8 @@ static void guc_stage_desc_init(struct i

 	memset(desc, 0, sizeof(*desc));

 	desc->attribute = GUC_STAGE_DESC_ATTR_ACTIVE | GUC_STAGE_DESC_ATTR_KERNEL;

+	if (is_high_priority(client))

+		desc->attribute |= GUC_STAGE_DESC_ATTR_PREEMPT;

 	desc->stage_id = client->stage_id;

 	desc->priority = client->priority;

 	desc->db_id = client->doorbell_id;

@@ -763,14 +770,14 @@ static int guc_init_doorbell_hw(struct i

 	/* Now for every client (and not only execbuf_client) make sure their

 	 * doorbells are known by the GuC */

-	//for (client = client_list; client != NULL; client = client->next)

-	{

-		ret = __create_doorbell(client);

-		if (ret) {

-			DRM_ERROR("Couldn't recreate client %u doorbell: %d\n",

-				client->stage_id, ret);

-			return ret;

-		}

+	ret = __create_doorbell(guc->execbuf_client);

+	if (ret)

+		return ret;

+

+	ret = __create_doorbell(guc->preempt_client);

+	if (ret) {

+		__destroy_doorbell(guc->execbuf_client);

+		return ret;

 	}

 	/* Read back & verify all (used & unused) doorbell registers */

@@ -895,6 +902,50 @@ static void guc_client_free(struct i915_

 	kfree(client);

 }

+static int guc_clients_create(struct intel_guc *guc)

+{

+	struct drm_i915_private *dev_priv = guc_to_i915(guc);

+	struct i915_guc_client *client;

+

+	GEM_BUG_ON(guc->execbuf_client);

+	GEM_BUG_ON(guc->preempt_client);

+

+	client = guc_client_alloc(dev_priv,

+				  INTEL_INFO(dev_priv)->ring_mask,

+				  GUC_CLIENT_PRIORITY_KMD_NORMAL,

+				  dev_priv->kernel_context);

+	if (IS_ERR(client)) {

+		DRM_ERROR("Failed to create GuC client for submission!\n");

+		return PTR_ERR(client);

+	}

+	guc->execbuf_client = client;

+

+	client = guc_client_alloc(dev_priv,

+				  INTEL_INFO(dev_priv)->ring_mask,

+				  GUC_CLIENT_PRIORITY_KMD_HIGH,

+				  dev_priv->preempt_context);

+	if (IS_ERR(client)) {

+		DRM_ERROR("Failed to create GuC client for preemption!\n");

+		guc_client_free(guc->execbuf_client);

+		guc->execbuf_client = NULL;

+		return PTR_ERR(client);

+	}

+	guc->preempt_client = client;

+

+	return 0;

+}

+

+static void guc_clients_destroy(struct intel_guc *guc)

+{

+	struct i915_guc_client *client;

+

+	client = fetch_and_zero(&guc->execbuf_client);

+	guc_client_free(client);

+

+	client = fetch_and_zero(&guc->preempt_client);

+	guc_client_free(client);

+}

+

 static void guc_policy_init(struct guc_policy *policy)

 {

 	policy->execution_quantum = POLICY_DEFAULT_EXECUTION_QUANTUM_US;

@@ -1134,7 +1185,6 @@ static void i915_guc_submission_unpark(s

 int i915_guc_submission_enable(struct drm_i915_private *dev_priv)

 {

 	struct intel_guc *guc = &dev_priv->guc;

-	struct i915_guc_client *client = guc->execbuf_client;

 	struct intel_engine_cs *engine;

 	enum intel_engine_id id;

 	int err;

@@ -1152,28 +1202,28 @@ int i915_guc_submission_enable(struct dr

 		     sizeof(struct guc_wq_item) *

 		     I915_NUM_ENGINES > GUC_WQ_SIZE);

-	if (!client) {

-		client = guc_client_alloc(dev_priv,

-					  INTEL_INFO(dev_priv)->ring_mask,

-					  GUC_CLIENT_PRIORITY_KMD_NORMAL,

-					  dev_priv->kernel_context);

-		if (IS_ERR(client)) {

-			DRM_ERROR("Failed to create GuC client for execbuf!\n");

-			return PTR_ERR(client);

-		}

-

-		guc->execbuf_client = client;

+	/*

+	 * We're being called on both module initialization and on reset,

+	 * until this flow is changed, we're using regular client presence to

+	 * determine which case are we in, and whether we should allocate new

+	 * clients or just reset their workqueues.

+	 */

+	if (!guc->execbuf_client) {

+		err = guc_clients_create(guc);

+		if (err)

+			return err;

+	} else {

+		guc_reset_wq(guc->execbuf_client);

+		guc_reset_wq(guc->preempt_client);

 	}

 	err = intel_guc_sample_forcewake(guc);

 	if (err)

-		goto err_execbuf_client;

-

-	guc_reset_wq(client);

+		goto err_free_clients;

 	err = guc_init_doorbell_hw(guc);

 	if (err)

-		goto err_execbuf_client;

+		goto err_free_clients;

 	/* Take over from manual control of ELSP (execlists) */

 	guc_interrupts_capture(dev_priv);

@@ -1187,9 +1237,8 @@ int i915_guc_submission_enable(struct dr

 	return 0;

-err_execbuf_client:

-	guc_client_free(guc->execbuf_client);

-	guc->execbuf_client = NULL;

+err_free_clients:

+	guc_clients_destroy(guc);

 	return err;

 }

@@ -1204,6 +1253,5 @@ void i915_guc_submission_disable(struct

 	/* Revert back to manual ELSP submission */

 	intel_engines_reset_default_submission(dev_priv);

-	guc_client_free(guc->execbuf_client);

-	guc->execbuf_client = NULL;

+	guc_clients_destroy(guc);

 }

--- a/drivers/gpu/drm/i915/intel_guc.h

+++ b/drivers/gpu/drm/i915/intel_guc.h

@@ -58,6 +58,7 @@ struct intel_guc {

 	void *shared_data_vaddr;

 	struct i915_guc_client *execbuf_client;

+	struct i915_guc_client *preempt_client;

 	DECLARE_BITMAP(doorbell_bitmap, GUC_NUM_DOORBELLS);

 	/* Cyclic counter mod pagesize	*/