5 files changed, 50 insertions, 13 deletions

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
index 668b067b71e2..b51adaac8752 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
@@ -143,11 +143,17 @@ static inline bool intel_guc_is_supported(struct intel_guc *guc)
 	return intel_uc_fw_is_supported(&guc->fw);
 }
 
-static inline bool intel_guc_is_enabled(struct intel_guc *guc)
+static inline bool intel_guc_is_wanted(struct intel_guc *guc)
 {
 	return intel_uc_fw_is_enabled(&guc->fw);
 }
 
+static inline bool intel_guc_is_used(struct intel_guc *guc)
+{
+	GEM_BUG_ON(__intel_uc_fw_status(&guc->fw) == INTEL_UC_FIRMWARE_SELECTED);
+	return intel_uc_fw_is_available(&guc->fw);
+}
+
 static inline bool intel_guc_is_fw_running(struct intel_guc *guc)
 {
 	return intel_uc_fw_is_running(&guc->fw);
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc.h b/drivers/gpu/drm/i915/gt/uc/intel_huc.h
index 644c059fe01d..a40b9cfc6c22 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_huc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_huc.h
@@ -41,11 +41,17 @@ static inline bool intel_huc_is_supported(struct intel_huc *huc)
 	return intel_uc_fw_is_supported(&huc->fw);
 }
 
-static inline bool intel_huc_is_enabled(struct intel_huc *huc)
+static inline bool intel_huc_is_wanted(struct intel_huc *huc)
 {
 	return intel_uc_fw_is_enabled(&huc->fw);
 }
 
+static inline bool intel_huc_is_used(struct intel_huc *huc)
+{
+	GEM_BUG_ON(__intel_uc_fw_status(&huc->fw) == INTEL_UC_FIRMWARE_SELECTED);
+	return intel_uc_fw_is_available(&huc->fw);
+}
+
 static inline bool intel_huc_is_authenticated(struct intel_huc *huc)
 {
 	return intel_uc_fw_is_running(&huc->fw);
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c b/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c
index eee193bf2cc4..9cdf4cbe691c 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_huc_fw.c
@@ -20,7 +20,7 @@ void intel_huc_fw_init_early(struct intel_huc *huc)
 	struct drm_i915_private *i915 = gt->i915;
 
 	intel_uc_fw_init_early(&huc->fw, INTEL_UC_FW_TYPE_HUC,
-			       intel_uc_uses_guc(uc),
+			       intel_uc_wants_guc(uc),
 			       INTEL_INFO(i915)->platform, INTEL_REVID(i915));
 }
 
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
index affc4d6f9ead..5825a6c3e0a0 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
@@ -48,17 +48,17 @@ static void __confirm_options(struct intel_uc *uc)
 	DRM_DEV_DEBUG_DRIVER(i915->drm.dev,
 			     "enable_guc=%d (guc:%s submission:%s huc:%s)\n",
 			     i915_modparams.enable_guc,
-			     yesno(intel_uc_uses_guc(uc)),
+			     yesno(intel_uc_wants_guc(uc)),
 			     yesno(intel_uc_uses_guc_submission(uc)),
-			     yesno(intel_uc_uses_huc(uc)));
+			     yesno(intel_uc_wants_huc(uc)));
 
 	if (i915_modparams.enable_guc == -1)
 		return;
 
 	if (i915_modparams.enable_guc == 0) {
-		GEM_BUG_ON(intel_uc_uses_guc(uc));
+		GEM_BUG_ON(intel_uc_wants_guc(uc));
 		GEM_BUG_ON(intel_uc_uses_guc_submission(uc));
-		GEM_BUG_ON(intel_uc_uses_huc(uc));
+		GEM_BUG_ON(intel_uc_wants_huc(uc));
 		return;
 	}
 
@@ -93,7 +93,7 @@ void intel_uc_init_early(struct intel_uc *uc)
 
 	__confirm_options(uc);
 
-	if (intel_uc_uses_guc(uc))
+	if (intel_uc_wants_guc(uc))
 		uc->ops = &uc_ops_on;
 	else
 		uc->ops = &uc_ops_off;
@@ -257,13 +257,13 @@ static void __uc_fetch_firmwares(struct intel_uc *uc)
 {
 	int err;
 
-	GEM_BUG_ON(!intel_uc_uses_guc(uc));
+	GEM_BUG_ON(!intel_uc_wants_guc(uc));
 
 	err = intel_uc_fw_fetch(&uc->guc.fw);
 	if (err)
 		return;
 
-	if (intel_uc_uses_huc(uc))
+	if (intel_uc_wants_huc(uc))
 		intel_uc_fw_fetch(&uc->huc.fw);
 }
 
@@ -279,7 +279,10 @@ static void __uc_init(struct intel_uc *uc)
 	struct intel_huc *huc = &uc->huc;
 	int ret;
 
-	GEM_BUG_ON(!intel_uc_uses_guc(uc));
+	GEM_BUG_ON(!intel_uc_wants_guc(uc));
+
+	if (!intel_uc_uses_guc(uc))
+		return;
 
 	/* XXX: GuC submission is unavailable for now */
 	GEM_BUG_ON(intel_uc_supports_guc_submission(uc));
@@ -402,7 +405,7 @@ static int __uc_init_hw(struct intel_uc *uc)
 	int ret, attempts;
 
 	GEM_BUG_ON(!intel_uc_supports_guc(uc));
-	GEM_BUG_ON(!intel_uc_uses_guc(uc));
+	GEM_BUG_ON(!intel_uc_wants_guc(uc));
 
 	if (!intel_uc_fw_is_available(&guc->fw)) {
 		ret = __uc_check_hw(uc) ||
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.h b/drivers/gpu/drm/i915/gt/uc/intel_uc.h
index 2ce993ceb60a..a41aaf353f88 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.h
@@ -40,6 +40,27 @@ void intel_uc_runtime_suspend(struct intel_uc *uc);
 int intel_uc_resume(struct intel_uc *uc);
 int intel_uc_runtime_resume(struct intel_uc *uc);
 
+/*
+ * We need to know as early as possible if we're going to use GuC or not to
+ * take the correct setup paths. Additionally, once we've started loading the
+ * GuC, it is unsafe to keep executing without it because some parts of the HW,
+ * a subset of which is not cleaned on GT reset, will start expecting the GuC FW
+ * to be running.
+ * To solve both these requirements, we commit to using the microcontrollers if
+ * the relevant modparam is set and the blobs are found on the system. At this
+ * stage, the only thing that can stop us from attempting to load the blobs on
+ * the HW and use them is a fundamental issue (e.g. no memory for our
+ * structures); if we hit such a problem during driver load we're broken even
+ * without GuC, so there is no point in trying to fall back.
+ *
+ * Given the above, we can be in one of 4 states, with the last one implying
+ * we're committed to using the microcontroller:
+ * - Not supported: not available in HW and/or firmware not defined.
+ * - Supported: available in HW and firmware defined.
+ * - Wanted: supported + enabled in modparam.
+ * - In use: wanted + firmware found on the system and successfully fetched.
+ */
+
 #define __uc_state_checker(x, state, required) \
 static inline bool intel_uc_##state##_##x(struct intel_uc *uc) \
 { \
@@ -48,7 +69,8 @@ static inline bool intel_uc_##state##_##x(struct intel_uc *uc) \
 
 #define uc_state_checkers(x) \
 __uc_state_checker(x, supports, supported) \
-__uc_state_checker(x, uses, enabled)
+__uc_state_checker(x, wants, wanted) \
+__uc_state_checker(x, uses, used)
 
 uc_state_checkers(guc);
 uc_state_checkers(huc);