drm/i915/guc: doorbell checking cleanup

A collection of very small cleanups/improvements around doorbell checking
that do not deserve their own patch:

- Move doorbell-related HW defs to intel_guc_reg.h

- use GUC_NUM_DOORBELLS instead of GUC_DOORBELL_INVALID where
  appropriate

- do not stop on error in guc_verify_doorbells

- do not print drbreg on error: the only content of the register
  apart from the valid bit is the lower part of the physical memory
  address, which we can't use even if valid because we don't know
  which descriptor it came from (since the doorbell is in an unexpected
  state)

- Move the checking of doorbell valid bit to a common helper.

v2: add more cleanups (move defs, use GUC_NUM_DOORBELLS, don't stop in
    guc_verify_doorbells) (Michal)

v3: move more things to intel_guc_reg, redefine
    GUC_DOORBELL_INVALID (Michal), drop guc_doorbell_qw since it just
    duplicates guc_doorbell_info

Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@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/20181022230427.5616-3-daniele.ceraolospurio@intel.com

drivers/gpu/drm/i915/intel_guc_fwif.h

@@ -39,6 +39,11 @@
 #define GUC_VIDEO_ENGINE2		4
 #define GUC_MAX_ENGINES_NUM		(GUC_VIDEO_ENGINE2 + 1)
 
+#define GUC_DOORBELL_INVALID		256
+
+#define GUC_DB_SIZE			(PAGE_SIZE)
+#define GUC_WQ_SIZE			(PAGE_SIZE * 2)
+
 /* Work queue item header definitions */
 #define WQ_STATUS_ACTIVE		1
 #define WQ_STATUS_SUSPENDED		2
@@ -59,9 +64,6 @@
 #define WQ_RING_TAIL_MAX		0x7FF	/* 2^11 QWords */
 #define WQ_RING_TAIL_MASK		(WQ_RING_TAIL_MAX << WQ_RING_TAIL_SHIFT)
 
-#define GUC_DOORBELL_ENABLED		1
-#define GUC_DOORBELL_DISABLED		0
-
 #define GUC_STAGE_DESC_ATTR_ACTIVE	BIT(0)
 #define GUC_STAGE_DESC_ATTR_PENDING_DB	BIT(1)
 #define GUC_STAGE_DESC_ATTR_KERNEL	BIT(2)
@@ -219,26 +221,6 @@ struct uc_css_header {
 	u32 header_info;
 } __packed;
 
-struct guc_doorbell_info {
-	u32 db_status;
-	u32 cookie;
-	u32 reserved[14];
-} __packed;
-
-union guc_doorbell_qw {
-	struct {
-		u32 db_status;
-		u32 cookie;
-	};
-	u64 value_qw;
-} __packed;
-
-#define GUC_NUM_DOORBELLS	256
-#define GUC_DOORBELL_INVALID	(GUC_NUM_DOORBELLS)
-
-#define GUC_DB_SIZE			(PAGE_SIZE)
-#define GUC_WQ_SIZE			(PAGE_SIZE * 2)
-
 /* Work item for submitting workloads into work queue of GuC. */
 struct guc_wq_item {
 	u32 header;

drivers/gpu/drm/i915/intel_guc_reg.h

@@ -104,6 +104,18 @@
 #define GUC_SEND_INTERRUPT		_MMIO(0xc4c8)
 #define   GUC_SEND_TRIGGER		  (1<<0)
 
+#define GUC_NUM_DOORBELLS		256
+
+/* format of the HW-monitored doorbell cacheline */
+struct guc_doorbell_info {
+	u32 db_status;
+#define GUC_DOORBELL_DISABLED		0
+#define GUC_DOORBELL_ENABLED		1
+
+	u32 cookie;
+	u32 reserved[14];
+} __packed;
+
 #define GEN8_DRBREGL(x)			_MMIO(0x1000 + (x) * 8)
 #define   GEN8_DRB_VALID		  (1<<0)
 #define GEN8_DRBREGU(x)			_MMIO(0x1000 + (x) * 8 + 4)

drivers/gpu/drm/i915/intel_guc_submission.c

@@ -192,6 +192,14 @@ static struct guc_doorbell_info *__get_doorbell(struct intel_guc_client *client)
 	return client->vaddr + client->doorbell_offset;
 }
 
+static bool __doorbell_valid(struct intel_guc *guc, u16 db_id)
+{
+	struct drm_i915_private *dev_priv = guc_to_i915(guc);
+
+	GEM_BUG_ON(db_id >= GUC_NUM_DOORBELLS);
+	return I915_READ(GEN8_DRBREGL(db_id)) & GEN8_DRB_VALID;
+}
+
 static void __init_doorbell(struct intel_guc_client *client)
 {
 	struct guc_doorbell_info *doorbell;
@@ -203,7 +211,6 @@ static void __init_doorbell(struct intel_guc_client *client)
 
 static void __fini_doorbell(struct intel_guc_client *client)
 {
-	struct drm_i915_private *dev_priv = guc_to_i915(client->guc);
 	struct guc_doorbell_info *doorbell;
 	u16 db_id = client->doorbell_id;
 
@@ -214,7 +221,7 @@ static void __fini_doorbell(struct intel_guc_client *client)
 	 * to go to zero after updating db_status before we call the GuC to
 	 * release the doorbell
 	 */
-	if (wait_for_us(!(I915_READ(GEN8_DRBREGL(db_id)) & GEN8_DRB_VALID), 10))
+	if (wait_for_us(!__doorbell_valid(client->guc, db_id), 10))
 		WARN_ONCE(true, "Doorbell never became invalid after disable\n");
 }
 
@@ -866,33 +873,31 @@ guc_reset_prepare(struct intel_engine_cs *engine)
 /* Check that a doorbell register is in the expected state */
 static bool doorbell_ok(struct intel_guc *guc, u16 db_id)
 {
-	struct drm_i915_private *dev_priv = guc_to_i915(guc);
-	u32 drbregl;
 	bool valid;
 
-	GEM_BUG_ON(db_id >= GUC_DOORBELL_INVALID);
+	GEM_BUG_ON(db_id >= GUC_NUM_DOORBELLS);
 
-	drbregl = I915_READ(GEN8_DRBREGL(db_id));
-	valid = drbregl & GEN8_DRB_VALID;
+	valid = __doorbell_valid(guc, db_id);
 
 	if (test_bit(db_id, guc->doorbell_bitmap) == valid)
 		return true;
 
-	DRM_DEBUG_DRIVER("Doorbell %d has unexpected state (0x%x): valid=%s\n",
-			 db_id, drbregl, yesno(valid));
+	DRM_DEBUG_DRIVER("Doorbell %u has unexpected state: valid=%s\n",
+			 db_id, yesno(valid));
 
 	return false;
 }
 
 static bool guc_verify_doorbells(struct intel_guc *guc)
 {
+	bool doorbells_ok = true;
 	u16 db_id;
 
 	for (db_id = 0; db_id < GUC_NUM_DOORBELLS; ++db_id)
 		if (!doorbell_ok(guc, db_id))
-			return false;
+			doorbells_ok = false;
 
-	return true;
+	return doorbells_ok;
 }
 
 /**