drm/i915: Implementation of GuC submission client

A GuC client has its own doorbell and workqueue. It maintains the
doorbell cache line, process description object and work queue item.

A default guc_client is created for the i915 driver to use for
normal-priority in-order submission.

Note that the created client is not yet ready for use; doorbell
allocation will fail as we haven't yet linked the GuC's context
descriptor to the default contexts for each ring (see later patch).

v2:
    Defer adding structure members until needed [Chris Wilson]
    Rationalise type declarations [Chris Wilson]

v5:
    Add GuC per-engine submission & seqno statistics.
    Move wq locking to encompass both get_space() and add_item().
    Take forcewake lock in host2guc_action() [Tom O'Rourke]

v6:
    Fix GuC doorbell cacheline selection code (the
        cacheline-within-page calculation was wrong).
    Rename GuC priorities to make them closer to the names used in
        the GuC firmware source, matching what the autogenerated
        versions will (probably) be.
    Add per-ring statistics to client.

Issue: VIZ-4884
Signed-off-by: Alex Dai <yu.dai@intel.com>
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Tom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_guc_submission.c

@@ -26,6 +26,529 @@
 #include "i915_drv.h"
 #include "intel_guc.h"
 
+/**
+ * DOC: GuC Client
+ *
+ * i915_guc_client:
+ * We use the term client to avoid confusion with contexts. A i915_guc_client is
+ * equivalent to GuC object guc_context_desc. This context descriptor is
+ * allocated from a pool of 1024 entries. Kernel driver will allocate doorbell
+ * and workqueue for it. Also the process descriptor (guc_process_desc), which
+ * is mapped to client space. So the client can write Work Item then ring the
+ * doorbell.
+ *
+ * To simplify the implementation, we allocate one gem object that contains all
+ * pages for doorbell, process descriptor and workqueue.
+ *
+ * The Scratch registers:
+ * There are 16 MMIO-based registers start from 0xC180. The kernel driver writes
+ * a value to the action register (SOFT_SCRATCH_0) along with any data. It then
+ * triggers an interrupt on the GuC via another register write (0xC4C8).
+ * Firmware writes a success/fail code back to the action register after
+ * processes the request. The kernel driver polls waiting for this update and
+ * then proceeds.
+ * See host2guc_action()
+ *
+ * Doorbells:
+ * Doorbells are interrupts to uKernel. A doorbell is a single cache line (QW)
+ * mapped into process space.
+ *
+ * Work Items:
+ * There are several types of work items that the host may place into a
+ * workqueue, each with its own requirements and limitations. Currently only
+ * WQ_TYPE_INORDER is needed to support legacy submission via GuC, which
+ * represents in-order queue. The kernel driver packs ring tail pointer and an
+ * ELSP context descriptor dword into Work Item.
+ * See guc_add_workqueue_item()
+ *
+ */
+
+/*
+ * Read GuC command/status register (SOFT_SCRATCH_0)
+ * Return true if it contains a response rather than a command
+ */
+static inline bool host2guc_action_response(struct drm_i915_private *dev_priv,
+					    u32 *status)
+{
+	u32 val = I915_READ(SOFT_SCRATCH(0));
+	*status = val;
+	return GUC2HOST_IS_RESPONSE(val);
+}
+
+static int host2guc_action(struct intel_guc *guc, u32 *data, u32 len)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+	u32 status;
+	int i;
+	int ret;
+
+	if (WARN_ON(len < 1 || len > 15))
+		return -EINVAL;
+
+	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
+	spin_lock(&dev_priv->guc.host2guc_lock);
+
+	dev_priv->guc.action_count += 1;
+	dev_priv->guc.action_cmd = data[0];
+
+	for (i = 0; i < len; i++)
+		I915_WRITE(SOFT_SCRATCH(i), data[i]);
+
+	POSTING_READ(SOFT_SCRATCH(i - 1));
+
+	I915_WRITE(HOST2GUC_INTERRUPT, HOST2GUC_TRIGGER);
+
+	/* No HOST2GUC command should take longer than 10ms */
+	ret = wait_for_atomic(host2guc_action_response(dev_priv, &status), 10);
+	if (status != GUC2HOST_STATUS_SUCCESS) {
+		/*
+		 * Either the GuC explicitly returned an error (which
+		 * we convert to -EIO here) or no response at all was
+		 * received within the timeout limit (-ETIMEDOUT)
+		 */
+		if (ret != -ETIMEDOUT)
+			ret = -EIO;
+
+		DRM_ERROR("GUC: host2guc action 0x%X failed. ret=%d "
+				"status=0x%08X response=0x%08X\n",
+				data[0], ret, status,
+				I915_READ(SOFT_SCRATCH(15)));
+
+		dev_priv->guc.action_fail += 1;
+		dev_priv->guc.action_err = ret;
+	}
+	dev_priv->guc.action_status = status;
+
+	spin_unlock(&dev_priv->guc.host2guc_lock);
+	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
+
+	return ret;
+}
+
+/*
+ * Tell the GuC to allocate or deallocate a specific doorbell
+ */
+
+static int host2guc_allocate_doorbell(struct intel_guc *guc,
+				      struct i915_guc_client *client)
+{
+	u32 data[2];
+
+	data[0] = HOST2GUC_ACTION_ALLOCATE_DOORBELL;
+	data[1] = client->ctx_index;
+
+	return host2guc_action(guc, data, 2);
+}
+
+static int host2guc_release_doorbell(struct intel_guc *guc,
+				     struct i915_guc_client *client)
+{
+	u32 data[2];
+
+	data[0] = HOST2GUC_ACTION_DEALLOCATE_DOORBELL;
+	data[1] = client->ctx_index;
+
+	return host2guc_action(guc, data, 2);
+}
+
+/*
+ * Initialise, update, or clear doorbell data shared with the GuC
+ *
+ * These functions modify shared data and so need access to the mapped
+ * client object which contains the page being used for the doorbell
+ */
+
+static void guc_init_doorbell(struct intel_guc *guc,
+			      struct i915_guc_client *client)
+{
+	struct guc_doorbell_info *doorbell;
+	void *base;
+
+	base = kmap_atomic(i915_gem_object_get_page(client->client_obj, 0));
+	doorbell = base + client->doorbell_offset;
+
+	doorbell->db_status = 1;
+	doorbell->cookie = 0;
+
+	kunmap_atomic(base);
+}
+
+static int guc_ring_doorbell(struct i915_guc_client *gc)
+{
+	struct guc_process_desc *desc;
+	union guc_doorbell_qw db_cmp, db_exc, db_ret;
+	union guc_doorbell_qw *db;
+	void *base;
+	int attempt = 2, ret = -EAGAIN;
+
+	base = kmap_atomic(i915_gem_object_get_page(gc->client_obj, 0));
+	desc = base + gc->proc_desc_offset;
+
+	/* Update the tail so it is visible to GuC */
+	desc->tail = gc->wq_tail;
+
+	/* current cookie */
+	db_cmp.db_status = GUC_DOORBELL_ENABLED;
+	db_cmp.cookie = gc->cookie;
+
+	/* cookie to be updated */
+	db_exc.db_status = GUC_DOORBELL_ENABLED;
+	db_exc.cookie = gc->cookie + 1;
+	if (db_exc.cookie == 0)
+		db_exc.cookie = 1;
+
+	/* pointer of current doorbell cacheline */
+	db = base + gc->doorbell_offset;
+
+	while (attempt--) {
+		/* lets ring the doorbell */
+		db_ret.value_qw = atomic64_cmpxchg((atomic64_t *)db,
+			db_cmp.value_qw, db_exc.value_qw);
+
+		/* if the exchange was successfully executed */
+		if (db_ret.value_qw == db_cmp.value_qw) {
+			/* db was successfully rung */
+			gc->cookie = db_exc.cookie;
+			ret = 0;
+			break;
+		}
+
+		/* XXX: doorbell was lost and need to acquire it again */
+		if (db_ret.db_status == GUC_DOORBELL_DISABLED)
+			break;
+
+		DRM_ERROR("Cookie mismatch. Expected %d, returned %d\n",
+			  db_cmp.cookie, db_ret.cookie);
+
+		/* update the cookie to newly read cookie from GuC */
+		db_cmp.cookie = db_ret.cookie;
+		db_exc.cookie = db_ret.cookie + 1;
+		if (db_exc.cookie == 0)
+			db_exc.cookie = 1;
+	}
+
+	kunmap_atomic(base);
+	return ret;
+}
+
+static void guc_disable_doorbell(struct intel_guc *guc,
+				 struct i915_guc_client *client)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+	struct guc_doorbell_info *doorbell;
+	void *base;
+	int drbreg = GEN8_DRBREGL(client->doorbell_id);
+	int value;
+
+	base = kmap_atomic(i915_gem_object_get_page(client->client_obj, 0));
+	doorbell = base + client->doorbell_offset;
+
+	doorbell->db_status = 0;
+
+	kunmap_atomic(base);
+
+	I915_WRITE(drbreg, I915_READ(drbreg) & ~GEN8_DRB_VALID);
+
+	value = I915_READ(drbreg);
+	WARN_ON((value & GEN8_DRB_VALID) != 0);
+
+	I915_WRITE(GEN8_DRBREGU(client->doorbell_id), 0);
+	I915_WRITE(drbreg, 0);
+
+	/* XXX: wait for any interrupts */
+	/* XXX: wait for workqueue to drain */
+}
+
+/*
+ * Select, assign and relase doorbell cachelines
+ *
+ * These functions track which doorbell cachelines are in use.
+ * The data they manipulate is protected by the host2guc lock.
+ */
+
+static uint32_t select_doorbell_cacheline(struct intel_guc *guc)
+{
+	const uint32_t cacheline_size = cache_line_size();
+	uint32_t offset;
+
+	spin_lock(&guc->host2guc_lock);
+
+	/* Doorbell uses a single cache line within a page */
+	offset = offset_in_page(guc->db_cacheline);
+
+	/* Moving to next cache line to reduce contention */
+	guc->db_cacheline += cacheline_size;
+
+	spin_unlock(&guc->host2guc_lock);
+
+	DRM_DEBUG_DRIVER("selected doorbell cacheline 0x%x, next 0x%x, linesize %u\n",
+			offset, guc->db_cacheline, cacheline_size);
+
+	return offset;
+}
+
+static uint16_t assign_doorbell(struct intel_guc *guc, uint32_t priority)
+{
+	/*
+	 * The bitmap is split into two halves; the first half is used for
+	 * normal priority contexts, the second half for high-priority ones.
+	 * Note that logically higher priorities are numerically less than
+	 * normal ones, so the test below means "is it high-priority?"
+	 */
+	const bool hi_pri = (priority <= GUC_CTX_PRIORITY_HIGH);
+	const uint16_t half = GUC_MAX_DOORBELLS / 2;
+	const uint16_t start = hi_pri ? half : 0;
+	const uint16_t end = start + half;
+	uint16_t id;
+
+	spin_lock(&guc->host2guc_lock);
+	id = find_next_zero_bit(guc->doorbell_bitmap, end, start);
+	if (id == end)
+		id = GUC_INVALID_DOORBELL_ID;
+	else
+		bitmap_set(guc->doorbell_bitmap, id, 1);
+	spin_unlock(&guc->host2guc_lock);
+
+	DRM_DEBUG_DRIVER("assigned %s priority doorbell id 0x%x\n",
+			hi_pri ? "high" : "normal", id);
+
+	return id;
+}
+
+static void release_doorbell(struct intel_guc *guc, uint16_t id)
+{
+	spin_lock(&guc->host2guc_lock);
+	bitmap_clear(guc->doorbell_bitmap, id, 1);
+	spin_unlock(&guc->host2guc_lock);
+}
+
+/*
+ * Initialise the process descriptor shared with the GuC firmware.
+ */
+static void guc_init_proc_desc(struct intel_guc *guc,
+			       struct i915_guc_client *client)
+{
+	struct guc_process_desc *desc;
+	void *base;
+
+	base = kmap_atomic(i915_gem_object_get_page(client->client_obj, 0));
+	desc = base + client->proc_desc_offset;
+
+	memset(desc, 0, sizeof(*desc));
+
+	/*
+	 * XXX: pDoorbell and WQVBaseAddress are pointers in process address
+	 * space for ring3 clients (set them as in mmap_ioctl) or kernel
+	 * space for kernel clients (map on demand instead? May make debug
+	 * easier to have it mapped).
+	 */
+	desc->wq_base_addr = 0;
+	desc->db_base_addr = 0;
+
+	desc->context_id = client->ctx_index;
+	desc->wq_size_bytes = client->wq_size;
+	desc->wq_status = WQ_STATUS_ACTIVE;
+	desc->priority = client->priority;
+
+	kunmap_atomic(base);
+}
+
+/*
+ * Initialise/clear the context descriptor shared with the GuC firmware.
+ *
+ * This descriptor tells the GuC where (in GGTT space) to find the important
+ * data structures relating to this client (doorbell, process descriptor,
+ * write queue, etc).
+ */
+
+static void guc_init_ctx_desc(struct intel_guc *guc,
+			      struct i915_guc_client *client)
+{
+	struct guc_context_desc desc;
+	struct sg_table *sg;
+
+	memset(&desc, 0, sizeof(desc));
+
+	desc.attribute = GUC_CTX_DESC_ATTR_ACTIVE | GUC_CTX_DESC_ATTR_KERNEL;
+	desc.context_id = client->ctx_index;
+	desc.priority = client->priority;
+	desc.engines_used = (1 << RCS) | (1 << VCS) | (1 << BCS) |
+			    (1 << VECS) | (1 << VCS2); /* all engines */
+	desc.db_id = client->doorbell_id;
+
+	/*
+	 * The CPU address is only needed at certain points, so kmap_atomic on
+	 * demand instead of storing it in the ctx descriptor.
+	 * XXX: May make debug easier to have it mapped
+	 */
+	desc.db_trigger_cpu = 0;
+	desc.db_trigger_uk = client->doorbell_offset +
+		i915_gem_obj_ggtt_offset(client->client_obj);
+	desc.db_trigger_phy = client->doorbell_offset +
+		sg_dma_address(client->client_obj->pages->sgl);
+
+	desc.process_desc = client->proc_desc_offset +
+		i915_gem_obj_ggtt_offset(client->client_obj);
+
+	desc.wq_addr = client->wq_offset +
+		i915_gem_obj_ggtt_offset(client->client_obj);
+
+	desc.wq_size = client->wq_size;
+
+	/*
+	 * XXX: Take LRCs from an existing intel_context if this is not an
+	 * IsKMDCreatedContext client
+	 */
+	desc.desc_private = (uintptr_t)client;
+
+	/* Pool context is pinned already */
+	sg = guc->ctx_pool_obj->pages;
+	sg_pcopy_from_buffer(sg->sgl, sg->nents, &desc, sizeof(desc),
+			     sizeof(desc) * client->ctx_index);
+}
+
+static void guc_fini_ctx_desc(struct intel_guc *guc,
+			      struct i915_guc_client *client)
+{
+	struct guc_context_desc desc;
+	struct sg_table *sg;
+
+	memset(&desc, 0, sizeof(desc));
+
+	sg = guc->ctx_pool_obj->pages;
+	sg_pcopy_from_buffer(sg->sgl, sg->nents, &desc, sizeof(desc),
+			     sizeof(desc) * client->ctx_index);
+}
+
+/* Get valid workqueue item and return it back to offset */
+static int guc_get_workqueue_space(struct i915_guc_client *gc, u32 *offset)
+{
+	struct guc_process_desc *desc;
+	void *base;
+	u32 size = sizeof(struct guc_wq_item);
+	int ret = 0, timeout_counter = 200;
+
+	base = kmap_atomic(i915_gem_object_get_page(gc->client_obj, 0));
+	desc = base + gc->proc_desc_offset;
+
+	while (timeout_counter-- > 0) {
+		ret = wait_for_atomic(CIRC_SPACE(gc->wq_tail, desc->head,
+				gc->wq_size) >= size, 1);
+
+		if (!ret) {
+			*offset = gc->wq_tail;
+
+			/* advance the tail for next workqueue item */
+			gc->wq_tail += size;
+			gc->wq_tail &= gc->wq_size - 1;
+
+			/* this will break the loop */
+			timeout_counter = 0;
+		}
+	};
+
+	kunmap_atomic(base);
+
+	return ret;
+}
+
+static int guc_add_workqueue_item(struct i915_guc_client *gc,
+				  struct drm_i915_gem_request *rq)
+{
+	enum intel_ring_id ring_id = rq->ring->id;
+	struct guc_wq_item *wqi;
+	void *base;
+	u32 tail, wq_len, wq_off = 0;
+	int ret;
+
+	ret = guc_get_workqueue_space(gc, &wq_off);
+	if (ret)
+		return ret;
+
+	/* For now workqueue item is 4 DWs; workqueue buffer is 2 pages. So we
+	 * should not have the case where structure wqi is across page, neither
+	 * wrapped to the beginning. This simplifies the implementation below.
+	 *
+	 * XXX: if not the case, we need save data to a temp wqi and copy it to
+	 * workqueue buffer dw by dw.
+	 */
+	WARN_ON(sizeof(struct guc_wq_item) != 16);
+	WARN_ON(wq_off & 3);
+
+	/* wq starts from the page after doorbell / process_desc */
+	base = kmap_atomic(i915_gem_object_get_page(gc->client_obj,
+			(wq_off + GUC_DB_SIZE) >> PAGE_SHIFT));
+	wq_off &= PAGE_SIZE - 1;
+	wqi = (struct guc_wq_item *)((char *)base + wq_off);
+
+	/* len does not include the header */
+	wq_len = sizeof(struct guc_wq_item) / sizeof(u32) - 1;
+	wqi->header = WQ_TYPE_INORDER |
+			(wq_len << WQ_LEN_SHIFT) |
+			(ring_id << WQ_TARGET_SHIFT) |
+			WQ_NO_WCFLUSH_WAIT;
+
+	/* The GuC wants only the low-order word of the context descriptor */
+	wqi->context_desc = (u32)intel_lr_context_descriptor(rq->ctx, rq->ring);
+
+	/* The GuC firmware wants the tail index in QWords, not bytes */
+	tail = rq->ringbuf->tail >> 3;
+	wqi->ring_tail = tail << WQ_RING_TAIL_SHIFT;
+	wqi->fence_id = 0; /*XXX: what fence to be here */
+
+	kunmap_atomic(base);
+
+	return 0;
+}
+
+/**
+ * i915_guc_submit() - Submit commands through GuC
+ * @client:	the guc client where commands will go through
+ * @ctx:	LRC where commands come from
+ * @ring:	HW engine that will excute the commands
+ *
+ * Return:	0 if succeed
+ */
+int i915_guc_submit(struct i915_guc_client *client,
+		    struct drm_i915_gem_request *rq)
+{
+	struct intel_guc *guc = client->guc;
+	enum intel_ring_id ring_id = rq->ring->id;
+	unsigned long flags;
+	int q_ret, b_ret;
+
+	spin_lock_irqsave(&client->wq_lock, flags);
+
+	q_ret = guc_add_workqueue_item(client, rq);
+	if (q_ret == 0)
+		b_ret = guc_ring_doorbell(client);
+
+	client->submissions[ring_id] += 1;
+	if (q_ret) {
+		client->q_fail += 1;
+		client->retcode = q_ret;
+	} else if (b_ret) {
+		client->b_fail += 1;
+		client->retcode = q_ret = b_ret;
+	} else {
+		client->retcode = 0;
+	}
+	spin_unlock_irqrestore(&client->wq_lock, flags);
+
+	spin_lock(&guc->host2guc_lock);
+	guc->submissions[ring_id] += 1;
+	guc->last_seqno[ring_id] = rq->seqno;
+	spin_unlock(&guc->host2guc_lock);
+
+	return q_ret;
+}
+
+/*
+ * Everything below here is concerned with setup & teardown, and is
+ * therefore not part of the somewhat time-critical batch-submission
+ * path of i915_guc_submit() above.
+ */
+
 /**
  * gem_allocate_guc_obj() - Allocate gem object for GuC usage
  * @dev:	drm device
@@ -79,6 +602,121 @@ static void gem_release_guc_obj(struct drm_i915_gem_object *obj)
 	drm_gem_object_unreference(&obj->base);
 }
 
+static void guc_client_free(struct drm_device *dev,
+			    struct i915_guc_client *client)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_guc *guc = &dev_priv->guc;
+
+	if (!client)
+		return;
+
+	if (client->doorbell_id != GUC_INVALID_DOORBELL_ID) {
+		/*
+		 * First disable the doorbell, then tell the GuC we've
+		 * finished with it, finally deallocate it in our bitmap
+		 */
+		guc_disable_doorbell(guc, client);
+		host2guc_release_doorbell(guc, client);
+		release_doorbell(guc, client->doorbell_id);
+	}
+
+	/*
+	 * XXX: wait for any outstanding submissions before freeing memory.
+	 * Be sure to drop any locks
+	 */
+
+	gem_release_guc_obj(client->client_obj);
+
+	if (client->ctx_index != GUC_INVALID_CTX_ID) {
+		guc_fini_ctx_desc(guc, client);
+		ida_simple_remove(&guc->ctx_ids, client->ctx_index);
+	}
+
+	kfree(client);
+}
+
+/**
+ * guc_client_alloc() - Allocate an i915_guc_client
+ * @dev:	drm device
+ * @priority:	four levels priority _CRITICAL, _HIGH, _NORMAL and _LOW
+ * 		The kernel client to replace ExecList submission is created with
+ * 		NORMAL priority. Priority of a client for scheduler can be HIGH,
+ * 		while a preemption context can use CRITICAL.
+ *
+ * Return:	An i915_guc_client object if success.
+ */
+static struct i915_guc_client *guc_client_alloc(struct drm_device *dev,
+						uint32_t priority)
+{
+	struct i915_guc_client *client;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_guc *guc = &dev_priv->guc;
+	struct drm_i915_gem_object *obj;
+
+	client = kzalloc(sizeof(*client), GFP_KERNEL);
+	if (!client)
+		return NULL;
+
+	client->doorbell_id = GUC_INVALID_DOORBELL_ID;
+	client->priority = priority;
+	client->guc = guc;
+
+	client->ctx_index = (uint32_t)ida_simple_get(&guc->ctx_ids, 0,
+			GUC_MAX_GPU_CONTEXTS, GFP_KERNEL);
+	if (client->ctx_index >= GUC_MAX_GPU_CONTEXTS) {
+		client->ctx_index = GUC_INVALID_CTX_ID;
+		goto err;
+	}
+
+	/* The first page is doorbell/proc_desc. Two followed pages are wq. */
+	obj = gem_allocate_guc_obj(dev, GUC_DB_SIZE + GUC_WQ_SIZE);
+	if (!obj)
+		goto err;
+
+	client->client_obj = obj;
+	client->wq_offset = GUC_DB_SIZE;
+	client->wq_size = GUC_WQ_SIZE;
+	spin_lock_init(&client->wq_lock);
+
+	client->doorbell_offset = select_doorbell_cacheline(guc);
+
+	/*
+	 * Since the doorbell only requires a single cacheline, we can save
+	 * space by putting the application process descriptor in the same
+	 * page. Use the half of the page that doesn't include the doorbell.
+	 */
+	if (client->doorbell_offset >= (GUC_DB_SIZE / 2))
+		client->proc_desc_offset = 0;
+	else
+		client->proc_desc_offset = (GUC_DB_SIZE / 2);
+
+	client->doorbell_id = assign_doorbell(guc, client->priority);
+	if (client->doorbell_id == GUC_INVALID_DOORBELL_ID)
+		/* XXX: evict a doorbell instead */
+		goto err;
+
+	guc_init_proc_desc(guc, client);
+	guc_init_ctx_desc(guc, client);
+	guc_init_doorbell(guc, client);
+
+	/* XXX: Any cache flushes needed? General domain mgmt calls? */
+
+	if (host2guc_allocate_doorbell(guc, client))
+		goto err;
+
+	DRM_DEBUG_DRIVER("new priority %u client %p: ctx_index %u db_id %u\n",
+		priority, client, client->ctx_index, client->doorbell_id);
+
+	return client;
+
+err:
+	DRM_ERROR("FAILED to create priority %u GuC client!\n", priority);
+
+	guc_client_free(dev, client);
+	return NULL;
+}
+
 static void guc_create_log(struct intel_guc *guc)
 {
 	struct drm_i915_private *dev_priv = guc_to_i915(guc);
@@ -142,6 +780,8 @@ int i915_guc_submission_init(struct drm_device *dev)
 	if (!guc->ctx_pool_obj)
 		return -ENOMEM;
 
+	spin_lock_init(&dev_priv->guc.host2guc_lock);
+
 	ida_init(&guc->ctx_ids);
 
 	guc_create_log(guc);
@@ -149,6 +789,32 @@ int i915_guc_submission_init(struct drm_device *dev)
 	return 0;
 }
 
+int i915_guc_submission_enable(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_guc *guc = &dev_priv->guc;
+	struct i915_guc_client *client;
+
+	/* client for execbuf submission */
+	client = guc_client_alloc(dev, GUC_CTX_PRIORITY_KMD_NORMAL);
+	if (!client) {
+		DRM_ERROR("Failed to create execbuf guc_client\n");
+		return -ENOMEM;
+	}
+
+	guc->execbuf_client = client;
+	return 0;
+}
+
+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->execbuf_client);
+	guc->execbuf_client = NULL;
+}
+
 void i915_guc_submission_fini(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;

drivers/gpu/drm/i915/intel_guc.h

@@ -27,6 +27,31 @@
 #include "intel_guc_fwif.h"
 #include "i915_guc_reg.h"
 
+struct i915_guc_client {
+	struct drm_i915_gem_object *client_obj;
+	struct intel_guc *guc;
+	uint32_t priority;
+	uint32_t ctx_index;
+
+	uint32_t proc_desc_offset;
+	uint32_t doorbell_offset;
+	uint32_t cookie;
+	uint16_t doorbell_id;
+	uint16_t padding;		/* Maintain alignment		*/
+
+	uint32_t wq_offset;
+	uint32_t wq_size;
+
+	spinlock_t wq_lock;		/* Protects all data below	*/
+	uint32_t wq_tail;
+
+	/* GuC submission statistics & status */
+	uint64_t submissions[I915_NUM_RINGS];
+	uint32_t q_fail;
+	uint32_t b_fail;
+	int retcode;
+};
+
 enum intel_guc_fw_status {
 	GUC_FIRMWARE_FAIL = -1,
 	GUC_FIRMWARE_NONE = 0,
@@ -60,6 +85,23 @@ struct intel_guc {
 
 	struct drm_i915_gem_object *ctx_pool_obj;
 	struct ida ctx_ids;
+
+	struct i915_guc_client *execbuf_client;
+
+	spinlock_t host2guc_lock;	/* Protects all data below	*/
+
+	DECLARE_BITMAP(doorbell_bitmap, GUC_MAX_DOORBELLS);
+	uint32_t db_cacheline;		/* Cyclic counter mod pagesize	*/
+
+	/* Action status & statistics */
+	uint64_t action_count;		/* Total commands issued	*/
+	uint32_t action_cmd;		/* Last command word		*/
+	uint32_t action_status;		/* Last return status		*/
+	uint32_t action_fail;		/* Total number of failures	*/
+	int32_t action_err;		/* Last error code		*/
+
+	uint64_t submissions[I915_NUM_RINGS];
+	uint32_t last_seqno[I915_NUM_RINGS];
 };
 
 /* intel_guc_loader.c */
@@ -70,6 +112,10 @@ extern const char *intel_guc_fw_status_repr(enum intel_guc_fw_status status);
 
 /* i915_guc_submission.c */
 int i915_guc_submission_init(struct drm_device *dev);
+int i915_guc_submission_enable(struct drm_device *dev);
+int i915_guc_submit(struct i915_guc_client *client,
+		    struct drm_i915_gem_request *rq);
+void i915_guc_submission_disable(struct drm_device *dev);
 void i915_guc_submission_fini(struct drm_device *dev);
 
 #endif

drivers/gpu/drm/i915/intel_guc_fwif.h

@@ -35,10 +35,10 @@
 #define GFXCORE_FAMILY_GEN9		12
 #define GFXCORE_FAMILY_UNKNOWN		0x7fffffff
 
-#define GUC_CTX_PRIORITY_CRITICAL	0
+#define GUC_CTX_PRIORITY_KMD_HIGH	0
 #define GUC_CTX_PRIORITY_HIGH		1
-#define GUC_CTX_PRIORITY_NORMAL		2
-#define GUC_CTX_PRIORITY_LOW		3
+#define GUC_CTX_PRIORITY_KMD_NORMAL	2
+#define GUC_CTX_PRIORITY_NORMAL		3
 
 #define GUC_MAX_GPU_CONTEXTS		1024
 #define	GUC_INVALID_CTX_ID		(GUC_MAX_GPU_CONTEXTS + 1)

drivers/gpu/drm/i915/intel_guc_loader.c

@@ -342,6 +342,8 @@ int intel_guc_ucode_load(struct drm_device *dev)
 		intel_guc_fw_status_repr(guc_fw->guc_fw_fetch_status),
 		intel_guc_fw_status_repr(guc_fw->guc_fw_load_status));
 
+	i915_guc_submission_disable(dev);
+
 	if (guc_fw->guc_fw_fetch_status == GUC_FIRMWARE_NONE)
 		return 0;
 
@@ -389,12 +391,20 @@ int intel_guc_ucode_load(struct drm_device *dev)
 		intel_guc_fw_status_repr(guc_fw->guc_fw_fetch_status),
 		intel_guc_fw_status_repr(guc_fw->guc_fw_load_status));
 
+	if (i915.enable_guc_submission) {
+		err = i915_guc_submission_enable(dev);
+		if (err)
+			goto fail;
+	}
+
 	return 0;
 
 fail:
 	if (guc_fw->guc_fw_load_status == GUC_FIRMWARE_PENDING)
 		guc_fw->guc_fw_load_status = GUC_FIRMWARE_FAIL;
 
+	i915_guc_submission_disable(dev);
+
 	return err;
 }