[Intel-gfx] [PATCH 1/3] drm/i915/guc: keep GuC objects mapped in kernel

[Dave Gordon]

With the new i915_gem_obj_pin_map() interface, it makes sense to keep
GuC objects (which are always pinned in memory and in the GGTT anyway)
mapped into kernel address space, rather than mapping and unmapping them
on each access.

This preliminary patch sets up the pin-and-map for all GuC-specific
objects, and updates the various setup/shutdown functions to use these
long-term mappings rather than doing their own kmap_atomic() calls.

Cc: <tvrtko.ursulin at intel.com>
Signed-off-by: Alex Dai <yu.dai at intel.com>
Signed-off-by: Dave Gordon <david.s.gordon at intel.com>
---
 drivers/gpu/drm/i915/i915_guc_submission.c | 37 +++++++++++-------------------
 drivers/gpu/drm/i915/intel_guc.h           |  1 +
 2 files changed, 14 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index da86bdb..f80f577 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -179,15 +179,11 @@ 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 = client->client_base + client->doorbell_offset;
 
-	doorbell->db_status = 1;
+	doorbell->db_status = GUC_DOORBELL_ENABLED;
 	doorbell->cookie = 0;
-
-	kunmap_atomic(base);
 }
 
 static int guc_ring_doorbell(struct i915_guc_client *gc)
@@ -256,16 +252,12 @@ static void guc_disable_doorbell(struct intel_guc *guc,
 {
 	struct drm_i915_private *dev_priv = guc_to_i915(guc);
 	struct guc_doorbell_info *doorbell;
-	void *base;
 	i915_reg_t 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;
+	doorbell = client->client_base + client->doorbell_offset;
 
-	kunmap_atomic(base);
+	doorbell->db_status = GUC_DOORBELL_DISABLED;
 
 	I915_WRITE(drbreg, I915_READ(drbreg) & ~GEN8_DRB_VALID);
 
@@ -341,10 +333,8 @@ 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;
+	desc = client->client_base + client->proc_desc_offset;
 
 	memset(desc, 0, sizeof(*desc));
 
@@ -361,8 +351,6 @@ static void guc_init_proc_desc(struct intel_guc *guc,
 	desc->wq_size_bytes = client->wq_size;
 	desc->wq_status = WQ_STATUS_ACTIVE;
 	desc->priority = client->priority;
-
-	kunmap_atomic(base);
 }
 
 /*
@@ -607,6 +595,7 @@ int i915_guc_submit(struct i915_guc_client *client,
  * This is a wrapper to create a gem obj. In order to use it inside GuC, the
  * object needs to be pinned lifetime. Also we must pin it to gtt space other
  * than [0, GUC_WOPCM_TOP) because this range is reserved inside GuC.
+ * The object is also pinned & mapped into kernel address space.
  *
  * Return:	A drm_i915_gem_object if successful, otherwise NULL.
  */
@@ -620,13 +609,14 @@ static struct drm_i915_gem_object *gem_allocate_guc_obj(struct drm_device *dev,
 	if (!obj)
 		return NULL;
 
-	if (i915_gem_object_get_pages(obj)) {
+	if (i915_gem_object_pin_map(obj) == NULL) {
 		drm_gem_object_unreference(&obj->base);
 		return NULL;
 	}
 
 	if (i915_gem_obj_ggtt_pin(obj, PAGE_SIZE,
 			PIN_OFFSET_BIAS | GUC_WOPCM_TOP)) {
+		i915_gem_object_unpin_map(obj);
 		drm_gem_object_unreference(&obj->base);
 		return NULL;
 	}
@@ -649,6 +639,8 @@ static void gem_release_guc_obj(struct drm_i915_gem_object *obj)
 	if (i915_gem_obj_is_pinned(obj))
 		i915_gem_object_ggtt_unpin(obj);
 
+	i915_gem_object_unpin_map(obj);
+
 	drm_gem_object_unreference(&obj->base);
 }
 
@@ -729,6 +721,8 @@ static struct i915_guc_client *guc_client_alloc(struct drm_device *dev,
 		goto err;
 
 	client->client_obj = obj;
+	client->client_base = obj->mapping;
+	WARN_ON(!client->client_base);
 	client->wq_offset = GUC_DB_SIZE;
 	client->wq_size = GUC_WQ_SIZE;
 
@@ -841,7 +835,6 @@ static void guc_create_ads(struct intel_guc *guc)
 	struct guc_policies *policies;
 	struct guc_mmio_reg_state *reg_state;
 	struct intel_engine_cs *engine;
-	struct page *page;
 	u32 size;
 
 	/* The ads obj includes the struct itself and buffers passed to GuC */
@@ -857,9 +850,7 @@ static void guc_create_ads(struct intel_guc *guc)
 
 		guc->ads_obj = obj;
 	}
-
-	page = i915_gem_object_get_page(obj, 0);
-	ads = kmap(page);
+	ads = obj->mapping;
 
 	/*
 	 * The GuC requires a "Golden Context" when it reinitialises
@@ -897,8 +888,6 @@ static void guc_create_ads(struct intel_guc *guc)
 
 	ads->reg_state_buffer = ads->reg_state_addr +
 			sizeof(struct guc_mmio_reg_state);
-
-	kunmap(page);
 }
 
 /*
diff --git a/drivers/gpu/drm/i915/intel_guc.h b/drivers/gpu/drm/i915/intel_guc.h
index 3bb85b1..9ab3564 100644
--- a/drivers/gpu/drm/i915/intel_guc.h
+++ b/drivers/gpu/drm/i915/intel_guc.h
@@ -31,6 +31,7 @@ struct drm_i915_gem_request;
 
 struct i915_guc_client {
 	struct drm_i915_gem_object *client_obj;
+	void *client_base;		/* Mapped address of above	*/
 	struct intel_context *owner;
 	struct intel_guc *guc;
 	uint32_t priority;
-- 
1.9.1