drm/i915/uncore: Do GT FIFO checks in early sanitize and forcewake get

We're mixing up the GT FIFO debug checks (overflows and such)
with RMbus unclaimed register checks. The two are quite different
things as RMbus is only relevant for display registers, and the
GT FIFO only relevant for GT registers.

Split the GT FIFO debugs out from the unclaimed register logic
and just do the checks during forcewake_get() and early init.
That is still sufficient to detect if any errors have happened.

Any errors would anyway be caused by overflowing the FIFO
rather than accessing specific registers, so trying to figure
out exactly when the error happened isn't particularly useful.
To fix such issues we'd rather have to do something to slow down
the rate at which registers are accessed (eg. increase
GT_FIFO_NUM_RESERVED_ENTRIES or something).

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260323101609.8391-3-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

Author: vsyrjala

drivers/gpu/drm/i915/intel_uncore.c

@@ -399,6 +399,35 @@ static void fw_domains_get_with_thread_status(struct intel_uncore *uncore,
 	__gen6_gt_wait_for_thread_c0(uncore);
 }
 
+static void
+gen6_check_for_fifo_debug(struct intel_uncore *uncore)
+{
+	u32 fifodbg;
+
+	fifodbg = __raw_uncore_read32(uncore, GTFIFODBG);
+
+	if (unlikely(fifodbg)) {
+		drm_dbg(&uncore->i915->drm, "GTFIFODBG = 0x08%x\n", fifodbg);
+		__raw_uncore_write32(uncore, GTFIFODBG, fifodbg);
+	}
+}
+
+static void
+fw_domains_get_normal_fifo(struct intel_uncore *uncore,
+			   enum forcewake_domains fw_domains)
+{
+	gen6_check_for_fifo_debug(uncore);
+	fw_domains_get_normal(uncore, fw_domains);
+}
+
+static void
+fw_domains_get_with_thread_status_fifo(struct intel_uncore *uncore,
+				       enum forcewake_domains fw_domains)
+{
+	gen6_check_for_fifo_debug(uncore);
+	fw_domains_get_with_thread_status(uncore, fw_domains);
+}
+
 static inline u32 fifo_free_entries(struct intel_uncore *uncore)
 {
 	u32 count = __raw_uncore_read32(uncore, GTFIFOCTL);
@@ -561,21 +590,6 @@ vlv_check_for_unclaimed_mmio(struct intel_uncore *uncore)
 	return true;
 }
 
-static bool
-gen6_check_for_fifo_debug(struct intel_uncore *uncore)
-{
-	u32 fifodbg;
-
-	fifodbg = __raw_uncore_read32(uncore, GTFIFODBG);
-
-	if (unlikely(fifodbg)) {
-		drm_dbg(&uncore->i915->drm, "GTFIFODBG = 0x08%x\n", fifodbg);
-		__raw_uncore_write32(uncore, GTFIFODBG, fifodbg);
-	}
-
-	return fifodbg;
-}
-
 static bool
 check_for_unclaimed_mmio(struct intel_uncore *uncore)
 {
@@ -592,9 +606,6 @@ check_for_unclaimed_mmio(struct intel_uncore *uncore)
 	if (intel_uncore_has_dbg_unclaimed(uncore))
 		ret |= vlv_check_for_unclaimed_mmio(uncore);
 
-	if (intel_uncore_has_fifo(uncore))
-		ret |= gen6_check_for_fifo_debug(uncore);
-
 	return ret;
 }
 
@@ -611,6 +622,9 @@ static void forcewake_early_sanitize(struct intel_uncore *uncore,
 				     GT_FIFO_CTL_RC6_POLICY_STALL);
 	}
 
+	if (intel_uncore_has_fifo(uncore))
+		gen6_check_for_fifo_debug(uncore);
+
 	iosf_mbi_punit_acquire();
 	intel_uncore_forcewake_reset(uncore);
 	if (restore_forcewake) {
@@ -2155,6 +2169,14 @@ static const struct intel_uncore_fw_get uncore_get_thread_status = {
 	.force_wake_get = fw_domains_get_with_thread_status
 };
 
+static const struct intel_uncore_fw_get uncore_get_normal_fifo = {
+	.force_wake_get = fw_domains_get_normal_fifo,
+};
+
+static const struct intel_uncore_fw_get uncore_get_thread_status_fifo = {
+	.force_wake_get = fw_domains_get_with_thread_status_fifo
+};
+
 static int intel_uncore_fw_domains_init(struct intel_uncore *uncore)
 {
 	struct drm_i915_private *i915 = uncore->i915;
@@ -2218,13 +2240,19 @@ static int intel_uncore_fw_domains_init(struct intel_uncore *uncore)
 		fw_domain_init(uncore, FW_DOMAIN_ID_MEDIA,
 			       FORCEWAKE_MEDIA_GEN9, FORCEWAKE_ACK_MEDIA_GEN9);
 	} else if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915)) {
-		uncore->fw_get_funcs = &uncore_get_normal;
+		if (intel_uncore_has_fifo(uncore))
+			uncore->fw_get_funcs = &uncore_get_normal_fifo;
+		else
+			uncore->fw_get_funcs = &uncore_get_normal;
 		fw_domain_init(uncore, FW_DOMAIN_ID_RENDER,
 			       FORCEWAKE_VLV, FORCEWAKE_ACK_VLV);
 		fw_domain_init(uncore, FW_DOMAIN_ID_MEDIA,
 			       FORCEWAKE_MEDIA_VLV, FORCEWAKE_ACK_MEDIA_VLV);
 	} else if (IS_HASWELL(i915) || IS_BROADWELL(i915)) {
-		uncore->fw_get_funcs = &uncore_get_thread_status;
+		if (intel_uncore_has_fifo(uncore))
+			uncore->fw_get_funcs = &uncore_get_thread_status_fifo;
+		else
+			uncore->fw_get_funcs = &uncore_get_thread_status;
 		fw_domain_init(uncore, FW_DOMAIN_ID_RENDER,
 			       FORCEWAKE_MT, FORCEWAKE_ACK_HSW);
 	} else if (IS_IVYBRIDGE(i915)) {
@@ -2239,7 +2267,7 @@ static int intel_uncore_fw_domains_init(struct intel_uncore *uncore)
 		 * (correctly) interpreted by the test below as MT
 		 * forcewake being disabled.
 		 */
-		uncore->fw_get_funcs = &uncore_get_thread_status;
+		uncore->fw_get_funcs = &uncore_get_thread_status_fifo;
 
 		/* We need to init first for ECOBUS access and then
 		 * determine later if we want to reinit, in case of MT access is
@@ -2270,7 +2298,7 @@ static int intel_uncore_fw_domains_init(struct intel_uncore *uncore)
 				       FORCEWAKE, FORCEWAKE_ACK);
 		}
 	} else if (GRAPHICS_VER(i915) == 6) {
-		uncore->fw_get_funcs = &uncore_get_thread_status;
+		uncore->fw_get_funcs = &uncore_get_thread_status_fifo;
 		fw_domain_init(uncore, FW_DOMAIN_ID_RENDER,
 			       FORCEWAKE, FORCEWAKE_ACK);
 	}