[Intel-xe] [PATCH v3 28/31] drm/xe: Allow GT looping and lookup on standalone media

[Matt Roper]

Allow xe_device_get_gt() and for_each_gt() to operate as expected on
platforms with standalone media.

FIXME: We need to figure out a consistent ID scheme for GTs.  This patch
keeps the pre-existing behavior of 0/1 being the GT IDs for both PVC
(multi-tile) and MTL (multi-GT), but depending on the direction we
decide to go with uapi, we may change this in the future (e.g., to
return 0/1 on PVC and 0/2 on MTL).  Or if we decide we only need to
expose tiles to userspace and not GTs, we may not even need ID numbers
for the GTs anymore.

v2:
 - Restructure a bit to make the assertions more clear.
 - Clarify in commit message that the goal here is to preserve existing
   behavior; UAPI-visible changes may be introduced in the future once
   we settle on what we really want.

Cc: Lucas De Marchi <lucas.demarchi at intel.com>
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
---
 drivers/gpu/drm/xe/xe_device.h | 40 +++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
index 0a3a9134dd18..ea3270ea0d46 100644
--- a/drivers/gpu/drm/xe/xe_device.h
+++ b/drivers/gpu/drm/xe/xe_device.h
@@ -53,18 +53,42 @@ static inline struct xe_tile *xe_device_get_root_tile(struct xe_device *xe)
 	return &xe->tiles[0];
 }
 
+#define XE_MAX_GT_PER_TILE 2
+
+static inline struct xe_gt *xe_tile_get_gt(struct xe_tile *tile, u8 gt_id)
+{
+	if (drm_WARN_ON(&tile_to_xe(tile)->drm, gt_id > XE_MAX_GT_PER_TILE))
+		gt_id = 0;
+
+	return gt_id ? tile->media_gt : tile->primary_gt;
+}
+
 static inline struct xe_gt *xe_device_get_gt(struct xe_device *xe, u8 gt_id)
 {
+	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
 	struct xe_gt *gt;
 
-	XE_BUG_ON(gt_id > XE_MAX_TILES_PER_DEVICE);
+	/*
+	 * FIXME: This only works for now because multi-tile and standalone
+	 * media are mutually exclusive on the platforms we have today.
+	 *
+	 * id => GT mapping may change once we settle on how we want to handle
+	 * our UAPI.
+	 */
+	if (MEDIA_VER(xe) >= 13) {
+		gt = xe_tile_get_gt(root_tile, gt_id);
+	} else {
+		if (drm_WARN_ON(&xe->drm, gt_id > XE_MAX_TILES_PER_DEVICE))
+			gt_id = 0;
 
-	gt = xe->tiles[gt_id].primary_gt;
-	if (drm_WARN_ON(&xe->drm, !gt))
+		gt = xe->tiles[gt_id].primary_gt;
+	}
+
+	if (!gt)
 		return NULL;
 
-	XE_BUG_ON(gt->info.id != gt_id);
-	XE_BUG_ON(gt->info.type == XE_GT_TYPE_UNINITIALIZED);
+	drm_WARN_ON(&xe->drm, gt->info.id != gt_id);
+	drm_WARN_ON(&xe->drm, gt->info.type == XE_GT_TYPE_UNINITIALIZED);
 
 	return gt;
 }
@@ -100,8 +124,12 @@ static inline void xe_device_guc_submission_disable(struct xe_device *xe)
 	for ((id__) = 0; (id__) < (xe__)->info.tile_count; (id__++)) \
 		for_each_if ((tile__) = &(xe__)->tiles[(id__)])
 
+/*
+ * FIXME: This only works for now since multi-tile and standalone media
+ * happen to be mutually exclusive.  Future platforms may change this...
+ */
 #define for_each_gt(gt__, xe__, id__) \
-	for ((id__) = 0; (id__) < (xe__)->info.tile_count; (id__++)) \
+	for ((id__) = 0; (id__) < (xe__)->info.tile_count + (MEDIA_VER(xe__) >= 13 ? 1 : 0); (id__++)) \
 		for_each_if ((gt__) = xe_device_get_gt((xe__), (id__)))
 
 static inline struct xe_force_wake * gt_to_fw(struct xe_gt *gt)
-- 
2.40.1