drm/i915/gt: Refactor l3cc/mocs availability

On dgfx, we only use l3cc and not mocs, but we share the table
containing both register definitions with Tigerlake. This confuses our
selftest that verifies that both sets of registers do contain the values
in our tables after various events (idling, reset, activity etc).

When constructing the table of register definitions, also include the
flags for which registers are valid so that information is computed
centrally and available to all callers.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Brian Welty <brian.welty@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200218162150.1300405-10-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_mocs.c

@@ -280,9 +280,32 @@ static const struct drm_i915_mocs_entry icl_mocs_table[] = {
 	GEN11_MOCS_ENTRIES
 };
 
-static bool get_mocs_settings(const struct drm_i915_private *i915,
-			      struct drm_i915_mocs_table *table)
+enum {
+	HAS_GLOBAL_MOCS = BIT(0),
+	HAS_ENGINE_MOCS = BIT(1),
+	HAS_RENDER_L3CC = BIT(2),
+};
+
+static bool has_l3cc(const struct drm_i915_private *i915)
 {
+	return true;
+}
+
+static bool has_global_mocs(const struct drm_i915_private *i915)
+{
+	return HAS_GLOBAL_MOCS_REGISTERS(i915);
+}
+
+static bool has_mocs(const struct drm_i915_private *i915)
+{
+	return !IS_DGFX(i915);
+}
+
+static unsigned int get_mocs_settings(const struct drm_i915_private *i915,
+				      struct drm_i915_mocs_table *table)
+{
+	unsigned int flags;
+
 	if (INTEL_GEN(i915) >= 12) {
 		table->size  = ARRAY_SIZE(tgl_mocs_table);
 		table->table = tgl_mocs_table;
@@ -302,11 +325,11 @@ static bool get_mocs_settings(const struct drm_i915_private *i915,
 	} else {
 		drm_WARN_ONCE(&i915->drm, INTEL_GEN(i915) >= 9,
 			      "Platform that should have a MOCS table does not.\n");
-		return false;
+		return 0;
 	}
 
 	if (GEM_DEBUG_WARN_ON(table->size > table->n_entries))
-		return false;
+		return 0;
 
 	/* WaDisableSkipCaching:skl,bxt,kbl,glk */
 	if (IS_GEN(i915, 9)) {
@@ -315,10 +338,20 @@ static bool get_mocs_settings(const struct drm_i915_private *i915,
 		for (i = 0; i < table->size; i++)
 			if (GEM_DEBUG_WARN_ON(table->table[i].l3cc_value &
 					      (L3_ESC(1) | L3_SCC(0x7))))
-				return false;
+				return 0;
 	}
 
-	return true;
+	flags = 0;
+	if (has_mocs(i915)) {
+		if (has_global_mocs(i915))
+			flags |= HAS_GLOBAL_MOCS;
+		else
+			flags |= HAS_ENGINE_MOCS;
+	}
+	if (has_l3cc(i915))
+		flags |= HAS_RENDER_L3CC;
+
+	return flags;
 }
 
 /*
@@ -411,18 +444,20 @@ static void init_l3cc_table(struct intel_engine_cs *engine,
 void intel_mocs_init_engine(struct intel_engine_cs *engine)
 {
 	struct drm_i915_mocs_table table;
+	unsigned int flags;
 
 	/* Called under a blanket forcewake */
 	assert_forcewakes_active(engine->uncore, FORCEWAKE_ALL);
 
-	if (!get_mocs_settings(engine->i915, &table))
+	flags = get_mocs_settings(engine->i915, &table);
+	if (!flags)
 		return;
 
 	/* Platforms with global MOCS do not need per-engine initialization. */
-	if (!HAS_GLOBAL_MOCS_REGISTERS(engine->i915))
+	if (flags & HAS_ENGINE_MOCS)
 		init_mocs_table(engine, &table);
 
-	if (engine->class == RENDER_CLASS)
+	if (flags & HAS_RENDER_L3CC && engine->class == RENDER_CLASS)
 		init_l3cc_table(engine, &table);
 }
 
@@ -431,26 +466,17 @@ static u32 global_mocs_offset(void)
 	return i915_mmio_reg_offset(GEN12_GLOBAL_MOCS(0));
 }
 
-static void init_global_mocs(struct intel_gt *gt)
+void intel_mocs_init(struct intel_gt *gt)
 {
 	struct drm_i915_mocs_table table;
+	unsigned int flags;
 
 	/*
 	 * LLC and eDRAM control values are not applicable to dgfx
 	 */
-	if (IS_DGFX(gt->i915))
-		return;
-
-	if (!get_mocs_settings(gt->i915, &table))
-		return;
-
-	__init_mocs_table(gt->uncore, &table, global_mocs_offset());
-}
-
-void intel_mocs_init(struct intel_gt *gt)
-{
-	if (HAS_GLOBAL_MOCS_REGISTERS(gt->i915))
-		init_global_mocs(gt);
+	flags = get_mocs_settings(gt->i915, &table);
+	if (flags & HAS_GLOBAL_MOCS)
+		__init_mocs_table(gt->uncore, &table, global_mocs_offset());
 }
 
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)

drivers/gpu/drm/i915/gt/selftest_mocs.c

@@ -12,7 +12,8 @@
 #include "selftests/igt_spinner.h"
 
 struct live_mocs {
-	struct drm_i915_mocs_table table;
+	struct drm_i915_mocs_table mocs;
+	struct drm_i915_mocs_table l3cc;
 	struct i915_vma *scratch;
 	void *vaddr;
 };
@@ -70,11 +71,22 @@ static struct i915_vma *create_scratch(struct intel_gt *gt)
 
 static int live_mocs_init(struct live_mocs *arg, struct intel_gt *gt)
 {
+	struct drm_i915_mocs_table table;
+	unsigned int flags;
 	int err;
 
-	if (!get_mocs_settings(gt->i915, &arg->table))
+	memset(arg, 0, sizeof(*arg));
+
+	flags = get_mocs_settings(gt->i915, &table);
+	if (!flags)
 		return -EINVAL;
 
+	if (flags & HAS_RENDER_L3CC)
+		arg->l3cc = table;
+
+	if (flags & (HAS_GLOBAL_MOCS | HAS_ENGINE_MOCS))
+		arg->mocs = table;
+
 	arg->scratch = create_scratch(gt);
 	if (IS_ERR(arg->scratch))
 		return PTR_ERR(arg->scratch);
@@ -223,9 +235,9 @@ static int check_mocs_engine(struct live_mocs *arg,
 	/* Read the mocs tables back using SRM */
 	offset = i915_ggtt_offset(vma);
 	if (!err)
-		err = read_mocs_table(rq, &arg->table, &offset);
+		err = read_mocs_table(rq, &arg->mocs, &offset);
 	if (!err && ce->engine->class == RENDER_CLASS)
-		err = read_l3cc_table(rq, &arg->table, &offset);
+		err = read_l3cc_table(rq, &arg->l3cc, &offset);
 	offset -= i915_ggtt_offset(vma);
 	GEM_BUG_ON(offset > PAGE_SIZE);
 
@@ -236,9 +248,9 @@ static int check_mocs_engine(struct live_mocs *arg,
 	/* Compare the results against the expected tables */
 	vaddr = arg->vaddr;
 	if (!err)
-		err = check_mocs_table(ce->engine, &arg->table, &vaddr);
+		err = check_mocs_table(ce->engine, &arg->mocs, &vaddr);
 	if (!err && ce->engine->class == RENDER_CLASS)
-		err = check_l3cc_table(ce->engine, &arg->table, &vaddr);
+		err = check_l3cc_table(ce->engine, &arg->l3cc, &vaddr);
 	if (err)
 		return err;