drm/i915: split gen8+ flush and bb_start emission functions

These functions are independent from the backend used and can therefore
be split out of the exelists submission file, so they can be re-used by
the upcoming GuC submission backend.

Based on a patch by Chris Wilson.
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201209233618.4287-3-chris@chris-wilson.co.ukSigned-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/Makefile

@@ -82,6 +82,7 @@ gt-y += \
 	gt/gen6_engine_cs.o \
 	gt/gen6_ppgtt.o \
 	gt/gen7_renderclear.o \
+	gt/gen8_engine_cs.o \
 	gt/gen8_ppgtt.o \
 	gt/intel_breadcrumbs.o \
 	gt/intel_context.o \

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

+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2014 Intel Corporation
+ */
+
+#ifndef __GEN8_ENGINE_CS_H__
+#define __GEN8_ENGINE_CS_H__
+
+#include <linux/types.h>
+
+struct i915_request;
+
+int gen8_emit_flush_rcs(struct i915_request *rq, u32 mode);
+int gen11_emit_flush_rcs(struct i915_request *rq, u32 mode);
+int gen12_emit_flush_rcs(struct i915_request *rq, u32 mode);
+
+int gen8_emit_flush_xcs(struct i915_request *rq, u32 mode);
+int gen12_emit_flush_xcs(struct i915_request *rq, u32 mode);
+
+int gen8_emit_init_breadcrumb(struct i915_request *rq);
+
+int gen8_emit_bb_start_noarb(struct i915_request *rq,
+			     u64 offset, u32 len,
+			     const unsigned int flags);
+int gen8_emit_bb_start(struct i915_request *rq,
+		       u64 offset, u32 len,
+		       const unsigned int flags);
+
+u32 *gen8_emit_fini_breadcrumb_xcs(struct i915_request *rq, u32 *cs);
+u32 *gen12_emit_fini_breadcrumb_xcs(struct i915_request *rq, u32 *cs);
+
+u32 *gen8_emit_fini_breadcrumb_rcs(struct i915_request *rq, u32 *cs);
+u32 *gen11_emit_fini_breadcrumb_rcs(struct i915_request *rq, u32 *cs);
+u32 *gen12_emit_fini_breadcrumb_rcs(struct i915_request *rq, u32 *cs);
+
+#endif /* __GEN8_ENGINE_CS_H__ */