drm/i915: switch KBL to the new stepping scheme

Add new symbolic names for revision ids, and convert KBL revids to use
them via the new stepping check macros.

This also fixes theoretical out of bounds access to kbl_revids array.

v3: upgrade dbg to warn on unknown revid (José)

v2: Rename stepping->step
Reviewed-by: NJosé Roberto de Souza <jose.souza@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/79b6c48211c6b214165391d350d556bad748f747.1616764798.git.jani.nikula@intel.com

drivers/gpu/drm/i915/gt/gen8_engine_cs.c

@@ -42,7 +42,7 @@ int gen8_emit_flush_rcs(struct i915_request *rq, u32 mode)
 			vf_flush_wa = true;
 
 		/* WaForGAMHang:kbl */
-		if (IS_KBL_GT_REVID(rq->engine->i915, 0, KBL_REVID_B0))
+		if (IS_KBL_GT_STEP(rq->engine->i915, 0, STEP_B0))
 			dc_flush_wa = true;
 	}
 

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

@@ -482,7 +482,7 @@ static void kbl_ctx_workarounds_init(struct intel_engine_cs *engine,
 	gen9_ctx_workarounds_init(engine, wal);
 
 	/* WaToEnableHwFixForPushConstHWBug:kbl */
-	if (IS_KBL_GT_REVID(i915, KBL_REVID_C0, REVID_FOREVER))
+	if (IS_KBL_GT_STEP(i915, STEP_C0, STEP_FOREVER))
 		wa_masked_en(wal, COMMON_SLICE_CHICKEN2,
 			     GEN8_SBE_DISABLE_REPLAY_BUF_OPTIMIZATION);
 
@@ -900,7 +900,7 @@ kbl_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
 	gen9_gt_workarounds_init(i915, wal);
 
 	/* WaDisableDynamicCreditSharing:kbl */
-	if (IS_KBL_GT_REVID(i915, 0, KBL_REVID_B0))
+	if (IS_KBL_GT_STEP(i915, 0, STEP_B0))
 		wa_write_or(wal,
 			    GAMT_CHKN_BIT_REG,
 			    GAMT_CHKN_DISABLE_DYNAMIC_CREDIT_SHARING);
@@ -2022,7 +2022,7 @@ xcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
 	struct drm_i915_private *i915 = engine->i915;
 
 	/* WaKBLVECSSemaphoreWaitPoll:kbl */
-	if (IS_KBL_GT_REVID(i915, KBL_REVID_A0, KBL_REVID_E0)) {
+	if (IS_KBL_GT_STEP(i915, STEP_A0, STEP_E0)) {
 		wa_write(wal,
 			 RING_SEMA_WAIT_POLL(engine->mmio_base),
 			 1);

drivers/gpu/drm/i915/i915_drv.c

@@ -272,7 +272,7 @@ static void intel_detect_preproduction_hw(struct drm_i915_private *dev_priv)
 	pre |= IS_HSW_EARLY_SDV(dev_priv);
 	pre |= IS_SKL_REVID(dev_priv, 0, SKL_REVID_F0);
 	pre |= IS_BXT_REVID(dev_priv, 0, BXT_REVID_B_LAST);
-	pre |= IS_KBL_GT_REVID(dev_priv, 0, KBL_REVID_A0);
+	pre |= IS_KBL_GT_STEP(dev_priv, 0, STEP_A0);
 	pre |= IS_GLK_REVID(dev_priv, 0, GLK_REVID_A2);
 
 	if (pre) {
@@ -306,6 +306,7 @@ static int i915_driver_early_probe(struct drm_i915_private *dev_priv)
 		return -ENODEV;
 
 	intel_device_info_subplatform_init(dev_priv);
+	intel_step_init(dev_priv);
 
 	intel_uncore_mmio_debug_init_early(&dev_priv->mmio_debug);
 	intel_uncore_init_early(&dev_priv->uncore, dev_priv);

drivers/gpu/drm/i915/i915_drv.h

@@ -1467,26 +1467,10 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
 #define IS_BXT_REVID(dev_priv, since, until) \
 	(IS_BROXTON(dev_priv) && IS_REVID(dev_priv, since, until))
 
-enum {
-	KBL_REVID_A0,
-	KBL_REVID_B0,
-	KBL_REVID_B1,
-	KBL_REVID_C0,
-	KBL_REVID_D0,
-	KBL_REVID_D1,
-	KBL_REVID_E0,
-	KBL_REVID_F0,
-	KBL_REVID_G0,
-};
-
-#define IS_KBL_GT_REVID(dev_priv, since, until) \
-	(IS_KABYLAKE(dev_priv) && \
-	 kbl_revids[INTEL_REVID(dev_priv)].gt_stepping >= since && \
-	 kbl_revids[INTEL_REVID(dev_priv)].gt_stepping <= until)
-#define IS_KBL_DISP_REVID(dev_priv, since, until) \
-	(IS_KABYLAKE(dev_priv) && \
-	 kbl_revids[INTEL_REVID(dev_priv)].disp_stepping >= since && \
-	 kbl_revids[INTEL_REVID(dev_priv)].disp_stepping <= until)
+#define IS_KBL_GT_STEP(dev_priv, since, until) \
+	(IS_KABYLAKE(dev_priv) && IS_GT_STEP(dev_priv, since, until))
+#define IS_KBL_DISPLAY_STEP(dev_priv, since, until) \
+	(IS_KABYLAKE(dev_priv) && IS_DISPLAY_STEP(dev_priv, since, until))
 
 #define GLK_REVID_A0		0x0
 #define GLK_REVID_A1		0x1

drivers/gpu/drm/i915/intel_pm.c

@@ -7233,12 +7233,12 @@ static void kbl_init_clock_gating(struct drm_i915_private *dev_priv)
 		   FBC_LLC_FULLY_OPEN);
 
 	/* WaDisableSDEUnitClockGating:kbl */
-	if (IS_KBL_GT_REVID(dev_priv, 0, KBL_REVID_B0))
+	if (IS_KBL_GT_STEP(dev_priv, 0, STEP_B0))
 		intel_uncore_write(&dev_priv->uncore, GEN8_UCGCTL6, intel_uncore_read(&dev_priv->uncore, GEN8_UCGCTL6) |
 			   GEN8_SDEUNIT_CLOCK_GATE_DISABLE);
 
 	/* WaDisableGamClockGating:kbl */
-	if (IS_KBL_GT_REVID(dev_priv, 0, KBL_REVID_B0))
+	if (IS_KBL_GT_STEP(dev_priv, 0, STEP_B0))
 		intel_uncore_write(&dev_priv->uncore, GEN6_UCGCTL1, intel_uncore_read(&dev_priv->uncore, GEN6_UCGCTL1) |
 			   GEN6_GAMUNIT_CLOCK_GATE_DISABLE);
 

drivers/gpu/drm/i915/intel_step.c

@@ -13,15 +13,17 @@
  * can test against in a regular manner.
  */
 
-const struct i915_rev_steppings kbl_revids[] = {
-	[0] = { .gt_stepping = KBL_REVID_A0, .disp_stepping = KBL_REVID_A0 },
-	[1] = { .gt_stepping = KBL_REVID_B0, .disp_stepping = KBL_REVID_B0 },
-	[2] = { .gt_stepping = KBL_REVID_C0, .disp_stepping = KBL_REVID_B0 },
-	[3] = { .gt_stepping = KBL_REVID_D0, .disp_stepping = KBL_REVID_B0 },
-	[4] = { .gt_stepping = KBL_REVID_F0, .disp_stepping = KBL_REVID_C0 },
-	[5] = { .gt_stepping = KBL_REVID_C0, .disp_stepping = KBL_REVID_B1 },
-	[6] = { .gt_stepping = KBL_REVID_D1, .disp_stepping = KBL_REVID_B1 },
-	[7] = { .gt_stepping = KBL_REVID_G0, .disp_stepping = KBL_REVID_C0 },
+
+/* FIXME: what about REVID_E0 */
+static const struct i915_rev_steppings kbl_revids[] = {
+	[0] = { .gt_stepping = STEP_A0, .disp_stepping = STEP_A0 },
+	[1] = { .gt_stepping = STEP_B0, .disp_stepping = STEP_B0 },
+	[2] = { .gt_stepping = STEP_C0, .disp_stepping = STEP_B0 },
+	[3] = { .gt_stepping = STEP_D0, .disp_stepping = STEP_B0 },
+	[4] = { .gt_stepping = STEP_F0, .disp_stepping = STEP_C0 },
+	[5] = { .gt_stepping = STEP_C0, .disp_stepping = STEP_B1 },
+	[6] = { .gt_stepping = STEP_D1, .disp_stepping = STEP_B1 },
+	[7] = { .gt_stepping = STEP_G0, .disp_stepping = STEP_C0 },
 };
 
 const struct i915_rev_steppings tgl_uy_revid_step_tbl[] = {
@@ -44,3 +46,52 @@ const struct i915_rev_steppings adls_revid_step_tbl[] = {
 	[0x8] = { .gt_stepping = STEP_C0, .disp_stepping = STEP_B0 },
 	[0xC] = { .gt_stepping = STEP_D0, .disp_stepping = STEP_C0 },
 };
+
+void intel_step_init(struct drm_i915_private *i915)
+{
+	const struct i915_rev_steppings *revids = NULL;
+	int size = 0;
+	int revid = INTEL_REVID(i915);
+	struct i915_rev_steppings step = {};
+
+	if (IS_KABYLAKE(i915)) {
+		revids = kbl_revids;
+		size = ARRAY_SIZE(kbl_revids);
+	}
+
+	/* Not using the stepping scheme for the platform yet. */
+	if (!revids)
+		return;
+
+	if (revid < size && revids[revid].gt_stepping != STEP_NONE) {
+		step = revids[revid];
+	} else {
+		drm_warn(&i915->drm, "Unknown revid 0x%02x\n", revid);
+
+		/*
+		 * If we hit a gap in the revid array, use the information for
+		 * the next revid.
+		 *
+		 * This may be wrong in all sorts of ways, especially if the
+		 * steppings in the array are not monotonically increasing, but
+		 * it's better than defaulting to 0.
+		 */
+		while (revid < size && revids[revid].gt_stepping == STEP_NONE)
+			revid++;
+
+		if (revid < size) {
+			drm_dbg(&i915->drm, "Using steppings for revid 0x%02x\n",
+				revid);
+			step = revids[revid];
+		} else {
+			drm_dbg(&i915->drm, "Using future steppings\n");
+			step.gt_stepping = STEP_FUTURE;
+			step.disp_stepping = STEP_FUTURE;
+		}
+	}
+
+	if (drm_WARN_ON(&i915->drm, step.gt_stepping == STEP_NONE))
+		return;
+
+	RUNTIME_INFO(i915)->step = step;
+}

drivers/gpu/drm/i915/intel_step.h

@@ -8,6 +8,8 @@
 
 #include <linux/types.h>
 
+struct drm_i915_private;
+
 struct i915_rev_steppings {
 	u8 gt_stepping;
 	u8 disp_stepping;
@@ -17,7 +19,6 @@ struct i915_rev_steppings {
 #define TGL_REVID_STEP_TBL_SIZE		2
 #define ADLS_REVID_STEP_TBL_SIZE	13
 
-extern const struct i915_rev_steppings kbl_revids[];
 extern const struct i915_rev_steppings tgl_uy_revid_step_tbl[TGL_UY_REVID_STEP_TBL_SIZE];
 extern const struct i915_rev_steppings tgl_revid_step_tbl[TGL_REVID_STEP_TBL_SIZE];
 extern const struct i915_rev_steppings adls_revid_step_tbl[ADLS_REVID_STEP_TBL_SIZE];
@@ -34,6 +35,14 @@ enum intel_step {
 	STEP_B1,
 	STEP_C0,
 	STEP_D0,
+	STEP_D1,
+	STEP_E0,
+	STEP_F0,
+	STEP_G0,
+	STEP_FUTURE,
+	STEP_FOREVER,
 };
 
+void intel_step_init(struct drm_i915_private *i915);
+
 #endif /* __INTEL_STEP_H__ */