drm/i915/wopcm: Don't fail on WOPCM partitioning failure

We don't have to immediately fail on WOPCM partitioning, we can wait
until we will start programming WOPCM registers. This should give us
more options if we decide to restore fallback in case of GuC failures.

v3: rebased

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190802184055.31988-7-michal.wajdeczko@intel.com

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

@@ -378,6 +378,11 @@ static int uc_init_wopcm(struct intel_uc *uc)
 	u32 mask;
 	int err;
 
+	if (unlikely(!base || !size)) {
+		i915_probe_error(gt->i915, "Unsuccessful WOPCM partitioning\n");
+		return -E2BIG;
+	}
+
 	GEM_BUG_ON(!intel_uc_supports_guc(uc));
 	GEM_BUG_ON(!(base & GUC_WOPCM_OFFSET_MASK));
 	GEM_BUG_ON(base & ~GUC_WOPCM_OFFSET_MASK);

drivers/gpu/drm/i915/i915_gem.c

@@ -1441,10 +1441,7 @@ int i915_gem_init(struct drm_i915_private *dev_priv)
 		return ret;
 
 	intel_uc_fetch_firmwares(&dev_priv->gt.uc);
-
-	ret = intel_wopcm_init(&dev_priv->wopcm);
-	if (ret)
-		goto err_uc_fw;
+	intel_wopcm_init(&dev_priv->wopcm);
 
 	/* This is just a security blanket to placate dragons.
 	 * On some systems, we very sporadically observe that the first TLBs
@@ -1568,7 +1565,6 @@ int i915_gem_init(struct drm_i915_private *dev_priv)
 	intel_uncore_forcewake_put(&dev_priv->uncore, FORCEWAKE_ALL);
 	mutex_unlock(&dev_priv->drm.struct_mutex);
 
-err_uc_fw:
 	intel_uc_cleanup_firmwares(&dev_priv->gt.uc);
 
 	if (ret != -EIO) {

drivers/gpu/drm/i915/intel_wopcm.c

@@ -156,12 +156,10 @@ static inline int check_hw_restriction(struct drm_i915_private *i915,
  * This function will partition WOPCM space based on GuC and HuC firmware sizes
  * and will allocate max remaining for use by GuC. This function will also
  * enforce platform dependent hardware restrictions on GuC WOPCM offset and
- * size. It will fail the WOPCM init if any of these checks were failed, so that
- * the following GuC firmware uploading would be aborted.
- *
- * Return: 0 on success, non-zero error code on failure.
+ * size. It will fail the WOPCM init if any of these checks fail, so that the
+ * following WOPCM registers setup and GuC firmware uploading would be aborted.
  */
-int intel_wopcm_init(struct intel_wopcm *wopcm)
+void intel_wopcm_init(struct intel_wopcm *wopcm)
 {
 	struct drm_i915_private *i915 = wopcm_to_i915(wopcm);
 	u32 guc_fw_size = intel_uc_fw_get_upload_size(&i915->gt.uc.guc.fw);
@@ -173,23 +171,25 @@ int intel_wopcm_init(struct intel_wopcm *wopcm)
 	int err;
 
 	if (!USES_GUC(i915))
-		return 0;
+		return;
 
 	GEM_BUG_ON(!wopcm->size);
+	GEM_BUG_ON(wopcm->guc.base);
+	GEM_BUG_ON(wopcm->guc.size);
 
 	if (i915_inject_probe_failure(i915))
-		return -E2BIG;
+		return;
 
 	if (guc_fw_size >= wopcm->size) {
 		DRM_ERROR("GuC FW (%uKiB) is too big to fit in WOPCM.",
 			  guc_fw_size / 1024);
-		return -E2BIG;
+		return;
 	}
 
 	if (huc_fw_size >= wopcm->size) {
 		DRM_ERROR("HuC FW (%uKiB) is too big to fit in WOPCM.",
 			  huc_fw_size / 1024);
-		return -E2BIG;
+		return;
 	}
 
 	guc_wopcm_base = ALIGN(huc_fw_size + WOPCM_RESERVED_SIZE,
@@ -197,7 +197,7 @@ int intel_wopcm_init(struct intel_wopcm *wopcm)
 	if ((guc_wopcm_base + ctx_rsvd) >= wopcm->size) {
 		DRM_ERROR("GuC WOPCM base (%uKiB) is too big.\n",
 			  guc_wopcm_base / 1024);
-		return -E2BIG;
+		return;
 	}
 
 	guc_wopcm_size = wopcm->size - guc_wopcm_base - ctx_rsvd;
@@ -211,16 +211,16 @@ int intel_wopcm_init(struct intel_wopcm *wopcm)
 		DRM_ERROR("Need %uKiB WOPCM for GuC, %uKiB available.\n",
 			  (guc_fw_size + guc_wopcm_rsvd) / 1024,
 			  guc_wopcm_size / 1024);
-		return -E2BIG;
+		return;
 	}
 
 	err = check_hw_restriction(i915, guc_wopcm_base, guc_wopcm_size,
 				   huc_fw_size);
 	if (err)
-		return err;
+		return;
 
 	wopcm->guc.base = guc_wopcm_base;
 	wopcm->guc.size = guc_wopcm_size;
-
-	return 0;
+	GEM_BUG_ON(!wopcm->guc.base);
+	GEM_BUG_ON(!wopcm->guc.size);
 }

drivers/gpu/drm/i915/intel_wopcm.h

@@ -55,6 +55,6 @@ static inline u32 intel_wopcm_guc_size(struct intel_wopcm *wopcm)
 }
 
 void intel_wopcm_init_early(struct intel_wopcm *wopcm);
-int intel_wopcm_init(struct intel_wopcm *wopcm);
+void intel_wopcm_init(struct intel_wopcm *wopcm);
 
 #endif