[PATCH 45/58] drm/i915/gt: Add timeline "mode"

[Chris Wilson]

Explicitly differentiate between the absolute and relative timelines,
and the global HWSP and ppHWSP relative offsets. When using a timeline
that is relative to a known status page, we can replace the absolute
addressing in the commands with indexed variants.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_timeline.c      | 21 ++++++++++++++++---
 drivers/gpu/drm/i915/gt/intel_timeline.h      |  2 +-
 .../gpu/drm/i915/gt/intel_timeline_types.h    | 10 +++++++--
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.c b/drivers/gpu/drm/i915/gt/intel_timeline.c
index b684322c879c..69052495c64a 100644
--- a/drivers/gpu/drm/i915/gt/intel_timeline.c
+++ b/drivers/gpu/drm/i915/gt/intel_timeline.c
@@ -226,7 +226,6 @@ static int intel_timeline_init(struct intel_timeline *timeline,
 
 	timeline->gt = gt;
 
-	timeline->has_initial_breadcrumb = !hwsp;
 	timeline->hwsp_cacheline = NULL;
 
 	if (!hwsp) {
@@ -243,13 +242,29 @@ static int intel_timeline_init(struct intel_timeline *timeline,
 			return PTR_ERR(cl);
 		}
 
+		timeline->mode = INTEL_TIMELINE_ABSOLUTE;
 		timeline->hwsp_cacheline = cl;
 		timeline->hwsp_offset = cacheline * CACHELINE_BYTES;
 
 		vaddr = page_mask_bits(cl->vaddr);
 	} else {
-		timeline->hwsp_offset = offset;
-		vaddr = i915_gem_object_pin_map(hwsp->obj, I915_MAP_WB);
+		int preferred;
+
+		if (offset & INTEL_TIMELINE_RELATIVE_CONTEXT) {
+			timeline->mode = INTEL_TIMELINE_RELATIVE_CONTEXT;
+			timeline->hwsp_offset =
+				offset & ~INTEL_TIMELINE_RELATIVE_CONTEXT;
+			preferred = i915_coherent_map_type(gt->i915);
+		} else {
+			timeline->mode = INTEL_TIMELINE_RELATIVE_ENGINE;
+			timeline->hwsp_offset = offset;
+			preferred = I915_MAP_WB;
+		}
+
+		vaddr = i915_gem_object_pin_map(hwsp->obj,
+						preferred | I915_MAP_OVERRIDE);
+		if (IS_ERR(vaddr))
+			vaddr = i915_gem_object_pin_map(hwsp->obj, I915_MAP_WC);
 		if (IS_ERR(vaddr))
 			return PTR_ERR(vaddr);
 	}
diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.h b/drivers/gpu/drm/i915/gt/intel_timeline.h
index 7d6218b55df6..e1d522329757 100644
--- a/drivers/gpu/drm/i915/gt/intel_timeline.h
+++ b/drivers/gpu/drm/i915/gt/intel_timeline.h
@@ -45,7 +45,7 @@ static inline void intel_timeline_put(struct intel_timeline *timeline)
 static inline bool
 intel_timeline_has_initial_breadcrumb(const struct intel_timeline *tl)
 {
-	return tl->has_initial_breadcrumb;
+	return tl->mode == INTEL_TIMELINE_ABSOLUTE;
 }
 
 static inline int __intel_timeline_sync_set(struct intel_timeline *tl,
diff --git a/drivers/gpu/drm/i915/gt/intel_timeline_types.h b/drivers/gpu/drm/i915/gt/intel_timeline_types.h
index c5995cc290a0..61938d103a13 100644
--- a/drivers/gpu/drm/i915/gt/intel_timeline_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_timeline_types.h
@@ -19,6 +19,12 @@ struct i915_syncmap;
 struct intel_gt;
 struct intel_timeline_hwsp;
 
+enum intel_timeline_mode {
+	INTEL_TIMELINE_ABSOLUTE = 0,
+	INTEL_TIMELINE_RELATIVE_CONTEXT = BIT(0),
+	INTEL_TIMELINE_RELATIVE_ENGINE  = BIT(1),
+};
+
 struct intel_timeline {
 	u64 fence_context;
 	u32 seqno;
@@ -44,6 +50,8 @@ struct intel_timeline {
 	atomic_t pin_count;
 	atomic_t active_count;
 
+	enum intel_timeline_mode mode;
+
 	const u32 *hwsp_seqno;
 	struct i915_vma *hwsp_ggtt;
 	u32 hwsp_offset;
@@ -51,8 +59,6 @@ struct intel_timeline {
 
 	struct intel_timeline_cacheline *hwsp_cacheline;
 
-	bool has_initial_breadcrumb;
-
 	/**
 	 * List of breadcrumbs associated with GPU requests currently
 	 * outstanding.
-- 
2.20.1