drm/i915/guc: kill the GuC client

We now only use 1 client without any plan to add more. The client is
also only holding information about the WQ and the process desc, so we
can just move those in the intel_guc structure and always use stage_id
0.

v2: fix comment (John)
v3: fix the comment for real, fix kerneldoc
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191205220243.27403-4-daniele.ceraolospurio@intel.com

Documentation/gpu/i915.rst

@@ -466,9 +466,6 @@ GuC-based command submission
 .. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
    :doc: GuC-based command submission
 
-.. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
-   :internal:
-
 HuC
 ---
 .. kernel-doc:: drivers/gpu/drm/i915/gt/uc/intel_huc.c

drivers/gpu/drm/i915/gt/intel_reset.c

@@ -21,6 +21,7 @@
 #include "intel_reset.h"
 
 #include "uc/intel_guc.h"
+#include "uc/intel_guc_submission.h"
 
 #define RESET_MAX_RETRIES 3
 
@@ -1085,6 +1086,7 @@ static inline int intel_gt_reset_engine(struct intel_engine_cs *engine)
 int intel_engine_reset(struct intel_engine_cs *engine, const char *msg)
 {
 	struct intel_gt *gt = engine->gt;
+	bool uses_guc = intel_engine_in_guc_submission_mode(engine);
 	int ret;
 
 	GEM_TRACE("%s flags=%lx\n", engine->name, gt->reset.flags);
@@ -1100,14 +1102,14 @@ int intel_engine_reset(struct intel_engine_cs *engine, const char *msg)
 			   "Resetting %s for %s\n", engine->name, msg);
 	atomic_inc(&engine->i915->gpu_error.reset_engine_count[engine->uabi_class]);
 
-	if (!engine->gt->uc.guc.execbuf_client)
+	if (!uses_guc)
 		ret = intel_gt_reset_engine(engine);
 	else
 		ret = intel_guc_reset_engine(&engine->gt->uc.guc, engine);
 	if (ret) {
 		/* If we fail here, we expect to fallback to a global reset */
 		DRM_DEBUG_DRIVER("%sFailed to reset %s, ret=%d\n",
-				 engine->gt->uc.guc.execbuf_client ? "GuC " : "",
+				 uses_guc ? "GuC " : "",
 				 engine->name, ret);
 		goto out;
 	}

drivers/gpu/drm/i915/gt/uc/intel_guc.h

@@ -46,9 +46,13 @@ struct intel_guc {
 
 	struct i915_vma *stage_desc_pool;
 	void *stage_desc_pool_vaddr;
-	struct ida stage_ids;
 
-	struct intel_guc_client *execbuf_client;
+	struct i915_vma *workqueue;
+	void *workqueue_vaddr;
+	spinlock_t wq_lock;
+
+	struct i915_vma *proc_desc;
+	void *proc_desc_vaddr;
 
 	/* Control params for fw initialization */
 	u32 params[GUC_CTL_MAX_DWORDS];

drivers/gpu/drm/i915/gt/uc/intel_guc_fwif.h

@@ -31,7 +31,6 @@
 
 #define GUC_DOORBELL_INVALID		256
 
-#define GUC_PD_SIZE			(PAGE_SIZE)
 #define GUC_WQ_SIZE			(PAGE_SIZE * 2)
 
 /* Work queue item header definitions */

drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c

@@ -27,24 +27,13 @@
  * code) matches the old submission model and will be updated as part of the
  * upgrade to the new flow.
  *
- * GuC client:
- * A intel_guc_client refers to a submission path through GuC. Currently, there
- * is only one client, which is charged with all submissions to the GuC. This
- * struct is the owner of a process descriptor and a workqueue (both 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
- * descriptors, and shares them with the GuC.
- * Currently, there exists a 1:1 mapping between a intel_guc_client and a
- * guc_stage_desc (via the client's stage_id), so effectively only one
- * gets used. This stage descriptor lets the GuC know about the workqueue and
+ * descriptors, and shares them with the GuC. Currently, we only use one
+ * descriptor. This stage descriptor lets the GuC know about the workqueue and
  * process descriptor. Theoretically, it also lets the GuC know about our HW
  * contexts (context ID, etc...), but we actually employ a kind of submission
- * where the GuC uses the LRCA sent via the work item instead (the single
- * guc_stage_desc associated to execbuf client contains information about the
- * default kernel context only, but this is essentially unused). This is called
+ * where the GuC uses the LRCA sent via the work item instead. This is called
  * a "proxy" submission.
  *
  * The Scratch registers:
@@ -71,33 +60,45 @@ static inline struct i915_priolist *to_priolist(struct rb_node *rb)
 	return rb_entry(rb, struct i915_priolist, node);
 }
 
-static inline bool is_high_priority(struct intel_guc_client *client)
+static struct guc_stage_desc *__get_stage_desc(struct intel_guc *guc, u32 id)
 {
-	return (client->priority == GUC_CLIENT_PRIORITY_KMD_HIGH ||
-		client->priority == GUC_CLIENT_PRIORITY_HIGH);
+	struct guc_stage_desc *base = guc->stage_desc_pool_vaddr;
+
+	return &base[id];
 }
 
-static struct guc_stage_desc *__get_stage_desc(struct intel_guc_client *client)
+static int guc_workqueue_create(struct intel_guc *guc)
 {
-	struct guc_stage_desc *base = client->guc->stage_desc_pool_vaddr;
-
-	return &base[client->stage_id];
+	return intel_guc_allocate_and_map_vma(guc, GUC_WQ_SIZE, &guc->workqueue,
+					      &guc->workqueue_vaddr);
 }
 
-static inline struct guc_process_desc *
-__get_process_desc(struct intel_guc_client *client)
+static void guc_workqueue_destroy(struct intel_guc *guc)
 {
-	return client->vaddr;
+	i915_vma_unpin_and_release(&guc->workqueue, I915_VMA_RELEASE_MAP);
 }
 
 /*
  * Initialise the process descriptor shared with the GuC firmware.
  */
-static void guc_proc_desc_init(struct intel_guc_client *client)
+static int guc_proc_desc_create(struct intel_guc *guc)
+{
+	const u32 size = PAGE_ALIGN(sizeof(struct guc_process_desc));
+
+	return intel_guc_allocate_and_map_vma(guc, size, &guc->proc_desc,
+					      &guc->proc_desc_vaddr);
+}
+
+static void guc_proc_desc_destroy(struct intel_guc *guc)
+{
+	i915_vma_unpin_and_release(&guc->proc_desc, I915_VMA_RELEASE_MAP);
+}
+
+static void guc_proc_desc_init(struct intel_guc *guc)
 {
 	struct guc_process_desc *desc;
 
-	desc = memset(__get_process_desc(client), 0, sizeof(*desc));
+	desc = memset(guc->proc_desc_vaddr, 0, sizeof(*desc));
 
 	/*
 	 * XXX: pDoorbell and WQVBaseAddress are pointers in process address
@@ -108,39 +109,27 @@ static void guc_proc_desc_init(struct intel_guc_client *client)
 	desc->wq_base_addr = 0;
 	desc->db_base_addr = 0;
 
-	desc->stage_id = client->stage_id;
 	desc->wq_size_bytes = GUC_WQ_SIZE;
 	desc->wq_status = WQ_STATUS_ACTIVE;
-	desc->priority = client->priority;
+	desc->priority = GUC_CLIENT_PRIORITY_KMD_NORMAL;
 }
 
-static void guc_proc_desc_fini(struct intel_guc_client *client)
+static void guc_proc_desc_fini(struct intel_guc *guc)
 {
-	struct guc_process_desc *desc;
-
-	desc = __get_process_desc(client);
-	memset(desc, 0, sizeof(*desc));
+	memset(guc->proc_desc_vaddr, 0, sizeof(struct guc_process_desc));
 }
 
 static int guc_stage_desc_pool_create(struct intel_guc *guc)
 {
 	u32 size = PAGE_ALIGN(sizeof(struct guc_stage_desc) *
 			      GUC_MAX_STAGE_DESCRIPTORS);
-	int ret;
 
-	ret = intel_guc_allocate_and_map_vma(guc, size, &guc->stage_desc_pool,
+	return intel_guc_allocate_and_map_vma(guc, size, &guc->stage_desc_pool,
 					      &guc->stage_desc_pool_vaddr);
-	if (ret)
-		return ret;
-
-	ida_init(&guc->stage_ids);
-
-	return 0;
 }
 
 static void guc_stage_desc_pool_destroy(struct intel_guc *guc)
 {
-	ida_destroy(&guc->stage_ids);
 	i915_vma_unpin_and_release(&guc->stage_desc_pool, I915_VMA_RELEASE_MAP);
 }
 
@@ -148,58 +137,49 @@ static void guc_stage_desc_pool_destroy(struct intel_guc *guc)
  * Initialise/clear the stage 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 (process descriptor, write queue,
+ * data structures related to work submission (process descriptor, write queue,
  * etc).
  */
-static void guc_stage_desc_init(struct intel_guc_client *client)
+static void guc_stage_desc_init(struct intel_guc *guc)
 {
-	struct intel_guc *guc = client->guc;
 	struct guc_stage_desc *desc;
-	u32 gfx_addr;
 
-	desc = __get_stage_desc(client);
+	/* we only use 1 stage desc, so hardcode it to 0 */
+	desc = __get_stage_desc(guc, 0);
 	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;
 
-	/*
-	 * The process descriptor and workqueue are all parts of the client
-	 * object, which the GuC will reference via the GGTT
-	 */
-	gfx_addr = intel_guc_ggtt_offset(guc, client->vma);
-	desc->process_desc = gfx_addr;
-	desc->wq_addr = gfx_addr + GUC_PD_SIZE;
-	desc->wq_size = GUC_WQ_SIZE;
+	desc->stage_id = 0;
+	desc->priority = GUC_CLIENT_PRIORITY_KMD_NORMAL;
 
-	desc->desc_private = ptr_to_u64(client);
+	desc->process_desc = intel_guc_ggtt_offset(guc, guc->proc_desc);
+	desc->wq_addr = intel_guc_ggtt_offset(guc, guc->workqueue);
+	desc->wq_size = GUC_WQ_SIZE;
 }
 
-static void guc_stage_desc_fini(struct intel_guc_client *client)
+static void guc_stage_desc_fini(struct intel_guc *guc)
 {
 	struct guc_stage_desc *desc;
 
-	desc = __get_stage_desc(client);
+	desc = __get_stage_desc(guc, 0);
 	memset(desc, 0, sizeof(*desc));
 }
 
 /* Construct a Work Item and append it to the GuC's Work Queue */
-static void guc_wq_item_append(struct intel_guc_client *client,
+static void guc_wq_item_append(struct intel_guc *guc,
 			       u32 target_engine, u32 context_desc,
 			       u32 ring_tail, u32 fence_id)
 {
 	/* wqi_len is in DWords, and does not include the one-word header */
 	const size_t wqi_size = sizeof(struct guc_wq_item);
 	const u32 wqi_len = wqi_size / sizeof(u32) - 1;
-	struct guc_process_desc *desc = __get_process_desc(client);
+	struct guc_process_desc *desc = guc->proc_desc_vaddr;
 	struct guc_wq_item *wqi;
 	u32 wq_off;
 
-	lockdep_assert_held(&client->wq_lock);
+	lockdep_assert_held(&guc->wq_lock);
 
 	/* 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
@@ -219,8 +199,7 @@ static void guc_wq_item_append(struct intel_guc_client *client,
 			      GUC_WQ_SIZE) < wqi_size);
 	GEM_BUG_ON(wq_off & (wqi_size - 1));
 
-	/* WQ starts from the page after process_desc */
-	wqi = client->vaddr + wq_off + GUC_PD_SIZE;
+	wqi = guc->workqueue_vaddr + wq_off;
 
 	/* Now fill in the 4-word work queue item */
 	wqi->header = WQ_TYPE_INORDER |
@@ -238,12 +217,11 @@ static void guc_wq_item_append(struct intel_guc_client *client,
 
 static void guc_add_request(struct intel_guc *guc, struct i915_request *rq)
 {
-	struct intel_guc_client *client = guc->execbuf_client;
 	struct intel_engine_cs *engine = rq->engine;
 	u32 ctx_desc = lower_32_bits(rq->hw_context->lrc_desc);
 	u32 ring_tail = intel_ring_set_tail(rq->ring, rq->tail) / sizeof(u64);
 
-	guc_wq_item_append(client, engine->guc_id, ctx_desc,
+	guc_wq_item_append(guc, engine->guc_id, ctx_desc,
 			   ring_tail, rq->fence.seqno);
 }
 
@@ -266,9 +244,8 @@ static void guc_submit(struct intel_engine_cs *engine,
 		       struct i915_request **end)
 {
 	struct intel_guc *guc = &engine->gt->uc.guc;
-	struct intel_guc_client *client = guc->execbuf_client;
 
-	spin_lock(&client->wq_lock);
+	spin_lock(&guc->wq_lock);
 
 	do {
 		struct i915_request *rq = *out++;
@@ -277,7 +254,7 @@ static void guc_submit(struct intel_engine_cs *engine,
 		guc_add_request(guc, rq);
 	} while (out != end);
 
-	spin_unlock(&client->wq_lock);
+	spin_unlock(&guc->wq_lock);
 }
 
 static inline int rq_prio(const struct i915_request *rq)
@@ -528,126 +505,6 @@ static void guc_reset_finish(struct intel_engine_cs *engine)
  * path of guc_submit() above.
  */
 
-/**
- * guc_client_alloc() - Allocate an intel_guc_client
- * @guc:	the intel_guc structure
- * @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 intel_guc_client object if success, else NULL.
- */
-static struct intel_guc_client *
-guc_client_alloc(struct intel_guc *guc, u32 priority)
-{
-	struct intel_guc_client *client;
-	struct i915_vma *vma;
-	void *vaddr;
-	int ret;
-
-	client = kzalloc(sizeof(*client), GFP_KERNEL);
-	if (!client)
-		return ERR_PTR(-ENOMEM);
-
-	client->guc = guc;
-	client->priority = priority;
-	spin_lock_init(&client->wq_lock);
-
-	ret = ida_simple_get(&guc->stage_ids, 0, GUC_MAX_STAGE_DESCRIPTORS,
-			     GFP_KERNEL);
-	if (ret < 0)
-		goto err_client;
-
-	client->stage_id = ret;
-
-	/* The first page is proc_desc. Two following pages are wq. */
-	vma = intel_guc_allocate_vma(guc, GUC_PD_SIZE + GUC_WQ_SIZE);
-	if (IS_ERR(vma)) {
-		ret = PTR_ERR(vma);
-		goto err_id;
-	}
-
-	/* We'll keep just the first (doorbell/proc) page permanently kmap'd. */
-	client->vma = vma;
-
-	vaddr = i915_gem_object_pin_map(vma->obj, I915_MAP_WB);
-	if (IS_ERR(vaddr)) {
-		ret = PTR_ERR(vaddr);
-		goto err_vma;
-	}
-	client->vaddr = vaddr;
-
-	DRM_DEBUG_DRIVER("new priority %u client %p: stage_id %u\n",
-			 priority, client, client->stage_id);
-
-	return client;
-
-err_vma:
-	i915_vma_unpin_and_release(&client->vma, 0);
-err_id:
-	ida_simple_remove(&guc->stage_ids, client->stage_id);
-err_client:
-	kfree(client);
-	return ERR_PTR(ret);
-}
-
-static void guc_client_free(struct intel_guc_client *client)
-{
-	i915_vma_unpin_and_release(&client->vma, I915_VMA_RELEASE_MAP);
-	ida_simple_remove(&client->guc->stage_ids, client->stage_id);
-	kfree(client);
-}
-
-static int guc_clients_create(struct intel_guc *guc)
-{
-	struct intel_guc_client *client;
-
-	GEM_BUG_ON(guc->execbuf_client);
-
-	client = guc_client_alloc(guc, GUC_CLIENT_PRIORITY_KMD_NORMAL);
-	if (IS_ERR(client)) {
-		DRM_ERROR("Failed to create GuC client for submission!\n");
-		return PTR_ERR(client);
-	}
-	guc->execbuf_client = client;
-
-	return 0;
-}
-
-static void guc_clients_destroy(struct intel_guc *guc)
-{
-	struct intel_guc_client *client;
-
-	client = fetch_and_zero(&guc->execbuf_client);
-	if (client)
-		guc_client_free(client);
-}
-
-static void __guc_client_enable(struct intel_guc_client *client)
-{
-	guc_proc_desc_init(client);
-	guc_stage_desc_init(client);
-}
-
-static void __guc_client_disable(struct intel_guc_client *client)
-{
-	/* Note: By the time we're here, GuC may have already been reset */
-	guc_stage_desc_fini(client);
-	guc_proc_desc_fini(client);
-}
-
-static void guc_clients_enable(struct intel_guc *guc)
-{
-	__guc_client_enable(guc->execbuf_client);
-}
-
-static void guc_clients_disable(struct intel_guc *guc)
-{
-	if (guc->execbuf_client)
-		__guc_client_disable(guc->execbuf_client);
-}
-
 /*
  * Set up the memory resources to be shared with the GuC (via the GGTT)
  * at firmware loading time.
@@ -668,12 +525,20 @@ int intel_guc_submission_init(struct intel_guc *guc)
 	 */
 	GEM_BUG_ON(!guc->stage_desc_pool);
 
-	ret = guc_clients_create(guc);
+	ret = guc_workqueue_create(guc);
 	if (ret)
 		goto err_pool;
 
+	ret = guc_proc_desc_create(guc);
+	if (ret)
+		goto err_workqueue;
+
+	spin_lock_init(&guc->wq_lock);
+
 	return 0;
 
+err_workqueue:
+	guc_workqueue_destroy(guc);
 err_pool:
 	guc_stage_desc_pool_destroy(guc);
 	return ret;
@@ -681,10 +546,11 @@ int intel_guc_submission_init(struct intel_guc *guc)
 
 void intel_guc_submission_fini(struct intel_guc *guc)
 {
-	guc_clients_destroy(guc);
-
-	if (guc->stage_desc_pool)
+	if (guc->stage_desc_pool) {
+		guc_proc_desc_destroy(guc);
+		guc_workqueue_destroy(guc);
 		guc_stage_desc_pool_destroy(guc);
+	}
 }
 
 static void guc_interrupts_capture(struct intel_gt *gt)
@@ -770,9 +636,8 @@ void intel_guc_submission_enable(struct intel_guc *guc)
 		     sizeof(struct guc_wq_item) *
 		     I915_NUM_ENGINES > GUC_WQ_SIZE);
 
-	GEM_BUG_ON(!guc->execbuf_client);
-
-	guc_clients_enable(guc);
+	guc_proc_desc_init(guc);
+	guc_stage_desc_init(guc);
 
 	/* Take over from manual control of ELSP (execlists) */
 	guc_interrupts_capture(gt);
@@ -789,8 +654,12 @@ void intel_guc_submission_disable(struct intel_guc *guc)
 
 	GEM_BUG_ON(gt->awake); /* GT should be parked first */
 
+	/* Note: By the time we're here, GuC may have already been reset */
+
 	guc_interrupts_release(gt);
-	guc_clients_disable(guc);
+
+	guc_stage_desc_fini(guc);
+	guc_proc_desc_fini(guc);
 }
 
 static bool __guc_submission_support(struct intel_guc *guc)
@@ -808,3 +677,8 @@ void intel_guc_submission_init_early(struct intel_guc *guc)
 {
 	guc->submission_supported = __guc_submission_support(guc);
 }
+
+bool intel_engine_in_guc_submission_mode(const struct intel_engine_cs *engine)
+{
+	return engine->set_default_submission == guc_set_default_submission;
+}

drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h

@@ -6,48 +6,10 @@
 #ifndef _INTEL_GUC_SUBMISSION_H_
 #define _INTEL_GUC_SUBMISSION_H_
 
-#include <linux/spinlock.h>
+#include <linux/types.h>
 
-#include "gt/intel_engine_types.h"
-
-#include "i915_gem.h"
-#include "i915_selftest.h"
-
-struct drm_i915_private;
-
-/*
- * This structure primarily describes the GEM object shared with the GuC.
- * The specs sometimes refer to this object as a "GuC context", but we use
- * the term "client" to avoid confusion with hardware contexts. This
- * GEM object is held for the entire lifetime of our interaction with
- * the GuC, being allocated before the GuC is loaded with its firmware.
- * Because there's no way to update the address used by the GuC after
- * initialisation, the shared object must stay pinned into the GGTT as
- * long as the GuC is in use. We also keep the first page (only) mapped
- * into kernel address space, as it includes shared data that must be
- * updated on every request submission.
- *
- * The single GEM object described here is actually made up of several
- * separate areas, as far as the GuC is concerned. The first page (kept
- * kmap'd) includes the "process descriptor" which holds sequence data for
- * the doorbell, and one cacheline which actually *is* the doorbell; a
- * write to this will "ring the doorbell" (i.e. send an interrupt to the
- * GuC). The subsequent  pages of the client object constitute the work
- * queue (a circular array of work items), again described in the process
- * descriptor. Work queue pages are mapped momentarily as required.
- */
-struct intel_guc_client {
-	struct i915_vma *vma;
-	void *vaddr;
-	struct intel_guc *guc;
-
-	/* bitmap of (host) engine ids */
-	u32 priority;
-	u32 stage_id;
-
-	/* Protects GuC client's WQ access */
-	spinlock_t wq_lock;
-};
+struct intel_guc;
+struct intel_engine_cs;
 
 void intel_guc_submission_init_early(struct intel_guc *guc);
 int intel_guc_submission_init(struct intel_guc *guc);
@@ -56,5 +18,6 @@ void intel_guc_submission_disable(struct intel_guc *guc);
 void intel_guc_submission_fini(struct intel_guc *guc);
 int intel_guc_preempt_work_create(struct intel_guc *guc);
 void intel_guc_preempt_work_destroy(struct intel_guc *guc);
+bool intel_engine_in_guc_submission_mode(const struct intel_engine_cs *engine);
 
 #endif

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1792,23 +1792,12 @@ static void i915_guc_log_info(struct seq_file *m,
 static int i915_guc_info(struct seq_file *m, void *data)
 {
 	struct drm_i915_private *dev_priv = node_to_i915(m->private);
-	const struct intel_guc *guc = &dev_priv->gt.uc.guc;
-	struct intel_guc_client *client = guc->execbuf_client;
 
 	if (!USES_GUC(dev_priv))
 		return -ENODEV;
 
 	i915_guc_log_info(m, dev_priv);
 
-	if (!USES_GUC_SUBMISSION(dev_priv))
-		return 0;
-
-	GEM_BUG_ON(!guc->execbuf_client);
-
-	seq_printf(m, "\nGuC execbuf client @ %p:\n", client);
-	seq_printf(m, "\tPriority %d, GuC stage index: %u\n",
-		   client->priority,
-		   client->stage_id);
 	/* Add more as required ... */
 
 	return 0;