[PATCH 1/2] drm/i915/chv: Determine CHV slice/subslice/EU info

[jeff.mcgee@intel.com]

From: Jeff McGee <jeff.mcgee@intel.com>

Total EU was already being detected on CHV, so we just add the
additional info parameters. The detection method is changed to
be more robust in the case of subslice fusing - we don't want
to trust the EU fuse bits corresponding to subslices which are
fused-off.

Signed-off-by: Jeff McGee <jeff.mcgee@intel.com>
---
 drivers/gpu/drm/i915/i915_dma.c | 40 ++++++++++++++++++++++++++++++++++------
 drivers/gpu/drm/i915/i915_reg.h |  2 ++
 2 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 053e178..04e5b55e 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -608,14 +608,42 @@ static void intel_device_info_runtime_init(struct drm_device *dev)
 
 	/* Initialize slice/subslice/EU info */
 	if (IS_CHERRYVIEW(dev)) {
-		u32 fuse, mask_eu;
+		u32 fuse, eu_dis;
 
 		fuse = I915_READ(CHV_FUSE_GT);
-		mask_eu = fuse & (CHV_FGT_EU_DIS_SS0_R0_MASK |
-				  CHV_FGT_EU_DIS_SS0_R1_MASK |
-				  CHV_FGT_EU_DIS_SS1_R0_MASK |
-				  CHV_FGT_EU_DIS_SS1_R1_MASK);
-		info->eu_total = 16 - hweight32(mask_eu);
+
+		info->slice_total = 1;
+
+		if (!(fuse & CHV_FGT_DISABLE_SS0)) {
+			info->subslice_per_slice++;
+			eu_dis = fuse & (CHV_FGT_EU_DIS_SS0_R0_MASK |
+					 CHV_FGT_EU_DIS_SS0_R1_MASK);
+			info->eu_total += 8 - hweight32(eu_dis);
+		}
+
+		if (!(fuse & CHV_FGT_DISABLE_SS1)) {
+			info->subslice_per_slice++;
+			eu_dis = fuse & (CHV_FGT_EU_DIS_SS1_R0_MASK |
+					CHV_FGT_EU_DIS_SS1_R1_MASK);
+			info->eu_total += 8 - hweight32(eu_dis);
+		}
+
+		info->subslice_total = info->subslice_per_slice;
+		/*
+		 * CHV expected to always have a uniform distribution of EU
+		 * across subslices.
+		*/
+		info->eu_per_subslice = info->subslice_total ?
+					info->eu_total / info->subslice_total :
+					0;
+		/*
+		 * CHV supports subslice power gating on devices with more than
+		 * one subslice, and supports EU power gating on devices with
+		 * more than one EU pair per subslice.
+		*/
+		info->has_slice_pg = 0;
+		info->has_subslice_pg = (info->subslice_total > 1) ? 1 : 0;
+		info->has_eu_pg = (info->eu_per_subslice > 2) ? 1 : 0;
 	} else if (IS_SKYLAKE(dev)) {
 		const int s_max = 3, ss_max = 4, eu_max = 8;
 		int s, ss;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 55143cb..a8b205d 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1522,6 +1522,8 @@ enum skl_disp_power_wells {
 
 /* Fuse readout registers for GT */
 #define CHV_FUSE_GT			(VLV_DISPLAY_BASE + 0x2168)
+#define   CHV_FGT_DISABLE_SS0		10
+#define   CHV_FGT_DISABLE_SS1		11
 #define   CHV_FGT_EU_DIS_SS0_R0_SHIFT	16
 #define   CHV_FGT_EU_DIS_SS0_R0_MASK	(0xf << CHV_FGT_EU_DIS_SS0_R0_SHIFT)
 #define   CHV_FGT_EU_DIS_SS0_R1_SHIFT	20
-- 
2.3.0

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