drm/i915/hsw: add missing disabled EUs registers reads

It turns out that HSW has a register that tells us how many EUs are
disabled per half-slice (roughly a similar notion to subslice). We
didn't read those registers so far as most userspace drivers didn't
need those values prior to Gen8, but an internal library would like to
have access to this.

Since we already have the getparam interface, there is no harm in
exposing this.

v2: Rename bits value (Joonas)

v3: s/GEM_BUG_ON/MISSING_CASE/ (Joonas)

v4: s/GEM_BUG_ON/MISSING_CASE/ again... (Lionel)
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180221204902.23084-1-lionel.g.landwerlin@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -2807,6 +2807,13 @@ enum i915_power_well_id {
 #define GEN9_RCS_FE_FSM2 _MMIO(0x22a4)
 
 /* Fuse readout registers for GT */
+#define HSW_PAVP_FUSE1			_MMIO(0x911C)
+#define   HSW_F1_EU_DIS_SHIFT		16
+#define   HSW_F1_EU_DIS_MASK		(0x3 << HSW_F1_EU_DIS_SHIFT)
+#define   HSW_F1_EU_DIS_10EUS		0
+#define   HSW_F1_EU_DIS_8EUS		1
+#define   HSW_F1_EU_DIS_6EUS		2
+
 #define CHV_FUSE_GT			_MMIO(VLV_DISPLAY_BASE + 0x2168)
 #define   CHV_FGT_DISABLE_SS0		(1 << 10)
 #define   CHV_FGT_DISABLE_SS1		(1 << 11)

drivers/gpu/drm/i915/intel_device_info.c

@@ -357,6 +357,59 @@ static void broadwell_sseu_info_init(struct drm_i915_private *dev_priv)
 	sseu->has_eu_pg = 0;
 }
 
+static void haswell_sseu_info_init(struct drm_i915_private *dev_priv)
+{
+	struct intel_device_info *info = mkwrite_device_info(dev_priv);
+	struct sseu_dev_info *sseu = &info->sseu;
+	u32 fuse1;
+
+	/*
+	 * There isn't a register to tell us how many slices/subslices. We
+	 * work off the PCI-ids here.
+	 */
+	switch (info->gt) {
+	default:
+		MISSING_CASE(info->gt);
+		/* fall through */
+	case 1:
+		sseu->slice_mask = BIT(0);
+		sseu->subslice_mask = BIT(0);
+		break;
+	case 2:
+		sseu->slice_mask = BIT(0);
+		sseu->subslice_mask = BIT(0) | BIT(1);
+		break;
+	case 3:
+		sseu->slice_mask = BIT(0) | BIT(1);
+		sseu->subslice_mask = BIT(0) | BIT(1);
+		break;
+	}
+
+	fuse1 = I915_READ(HSW_PAVP_FUSE1);
+	switch ((fuse1 & HSW_F1_EU_DIS_MASK) >> HSW_F1_EU_DIS_SHIFT) {
+	default:
+		MISSING_CASE((fuse1 & HSW_F1_EU_DIS_MASK) >>
+			     HSW_F1_EU_DIS_SHIFT);
+		/* fall through */
+	case HSW_F1_EU_DIS_10EUS:
+		sseu->eu_per_subslice = 10;
+		break;
+	case HSW_F1_EU_DIS_8EUS:
+		sseu->eu_per_subslice = 8;
+		break;
+	case HSW_F1_EU_DIS_6EUS:
+		sseu->eu_per_subslice = 6;
+		break;
+	}
+
+	sseu->eu_total = sseu_subslice_total(sseu) * sseu->eu_per_subslice;
+
+	/* No powergating for you. */
+	sseu->has_slice_pg = 0;
+	sseu->has_subslice_pg = 0;
+	sseu->has_eu_pg = 0;
+}
+
 static u32 read_reference_ts_freq(struct drm_i915_private *dev_priv)
 {
 	u32 ts_override = I915_READ(GEN9_TIMESTAMP_OVERRIDE);
@@ -574,7 +627,9 @@ void intel_device_info_runtime_init(struct intel_device_info *info)
 	}
 
 	/* Initialize slice/subslice/EU info */
-	if (IS_CHERRYVIEW(dev_priv))
+	if (IS_HASWELL(dev_priv))
+		haswell_sseu_info_init(dev_priv);
+	else if (IS_CHERRYVIEW(dev_priv))
 		cherryview_sseu_info_init(dev_priv);
 	else if (IS_BROADWELL(dev_priv))
 		broadwell_sseu_info_init(dev_priv);