1 files changed, 159 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_sseu.c b/drivers/gpu/drm/i915/gt/intel_sseu.c
new file mode 100644
index 000000000000..a0756f006f5f
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_sseu.c
@@ -0,0 +1,159 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include "i915_drv.h"
+#include "intel_lrc_reg.h"
+#include "intel_sseu.h"
+
+unsigned int
+intel_sseu_subslice_total(const struct sseu_dev_info *sseu)
+{
+	unsigned int i, total = 0;
+
+	for (i = 0; i < ARRAY_SIZE(sseu->subslice_mask); i++)
+		total += hweight8(sseu->subslice_mask[i]);
+
+	return total;
+}
+
+unsigned int
+intel_sseu_subslices_per_slice(const struct sseu_dev_info *sseu, u8 slice)
+{
+	return hweight8(sseu->subslice_mask[slice]);
+}
+
+u32 intel_sseu_make_rpcs(struct drm_i915_private *i915,
+			 const struct intel_sseu *req_sseu)
+{
+	const struct sseu_dev_info *sseu = &RUNTIME_INFO(i915)->sseu;
+	bool subslice_pg = sseu->has_subslice_pg;
+	struct intel_sseu ctx_sseu;
+	u8 slices, subslices;
+	u32 rpcs = 0;
+
+	/*
+	 * No explicit RPCS request is needed to ensure full
+	 * slice/subslice/EU enablement prior to Gen9.
+	 */
+	if (INTEL_GEN(i915) < 9)
+		return 0;
+
+	/*
+	 * If i915/perf is active, we want a stable powergating configuration
+	 * on the system.
+	 *
+	 * We could choose full enablement, but on ICL we know there are use
+	 * cases which disable slices for functional, apart for performance
+	 * reasons. So in this case we select a known stable subset.
+	 */
+	if (!i915->perf.oa.exclusive_stream) {
+		ctx_sseu = *req_sseu;
+	} else {
+		ctx_sseu = intel_sseu_from_device_info(sseu);
+
+		if (IS_GEN(i915, 11)) {
+			/*
+			 * We only need subslice count so it doesn't matter
+			 * which ones we select - just turn off low bits in the
+			 * amount of half of all available subslices per slice.
+			 */
+			ctx_sseu.subslice_mask =
+				~(~0 << (hweight8(ctx_sseu.subslice_mask) / 2));
+			ctx_sseu.slice_mask = 0x1;
+		}
+	}
+
+	slices = hweight8(ctx_sseu.slice_mask);
+	subslices = hweight8(ctx_sseu.subslice_mask);
+
+	/*
+	 * Since the SScount bitfield in GEN8_R_PWR_CLK_STATE is only three bits
+	 * wide and Icelake has up to eight subslices, specfial programming is
+	 * needed in order to correctly enable all subslices.
+	 *
+	 * According to documentation software must consider the configuration
+	 * as 2x4x8 and hardware will translate this to 1x8x8.
+	 *
+	 * Furthemore, even though SScount is three bits, maximum documented
+	 * value for it is four. From this some rules/restrictions follow:
+	 *
+	 * 1.
+	 * If enabled subslice count is greater than four, two whole slices must
+	 * be enabled instead.
+	 *
+	 * 2.
+	 * When more than one slice is enabled, hardware ignores the subslice
+	 * count altogether.
+	 *
+	 * From these restrictions it follows that it is not possible to enable
+	 * a count of subslices between the SScount maximum of four restriction,
+	 * and the maximum available number on a particular SKU. Either all
+	 * subslices are enabled, or a count between one and four on the first
+	 * slice.
+	 */
+	if (IS_GEN(i915, 11) &&
+	    slices == 1 &&
+	    subslices > min_t(u8, 4, hweight8(sseu->subslice_mask[0]) / 2)) {
+		GEM_BUG_ON(subslices & 1);
+
+		subslice_pg = false;
+		slices *= 2;
+	}
+
+	/*
+	 * Starting in Gen9, render power gating can leave
+	 * slice/subslice/EU in a partially enabled state. We
+	 * must make an explicit request through RPCS for full
+	 * enablement.
+	 */
+	if (sseu->has_slice_pg) {
+		u32 mask, val = slices;
+
+		if (INTEL_GEN(i915) >= 11) {
+			mask = GEN11_RPCS_S_CNT_MASK;
+			val <<= GEN11_RPCS_S_CNT_SHIFT;
+		} else {
+			mask = GEN8_RPCS_S_CNT_MASK;
+			val <<= GEN8_RPCS_S_CNT_SHIFT;
+		}
+
+		GEM_BUG_ON(val & ~mask);
+		val &= mask;
+
+		rpcs |= GEN8_RPCS_ENABLE | GEN8_RPCS_S_CNT_ENABLE | val;
+	}
+
+	if (subslice_pg) {
+		u32 val = subslices;
+
+		val <<= GEN8_RPCS_SS_CNT_SHIFT;
+
+		GEM_BUG_ON(val & ~GEN8_RPCS_SS_CNT_MASK);
+		val &= GEN8_RPCS_SS_CNT_MASK;
+
+		rpcs |= GEN8_RPCS_ENABLE | GEN8_RPCS_SS_CNT_ENABLE | val;
+	}
+
+	if (sseu->has_eu_pg) {
+		u32 val;
+
+		val = ctx_sseu.min_eus_per_subslice << GEN8_RPCS_EU_MIN_SHIFT;
+		GEM_BUG_ON(val & ~GEN8_RPCS_EU_MIN_MASK);
+		val &= GEN8_RPCS_EU_MIN_MASK;
+
+		rpcs |= val;
+
+		val = ctx_sseu.max_eus_per_subslice << GEN8_RPCS_EU_MAX_SHIFT;
+		GEM_BUG_ON(val & ~GEN8_RPCS_EU_MAX_MASK);
+		val &= GEN8_RPCS_EU_MAX_MASK;
+
+		rpcs |= val;
+
+		rpcs |= GEN8_RPCS_ENABLE;
+	}
+
+	return rpcs;
+}