[Intel-xe] [RFC PATCH v3 1/3] drm/xe: Introduce function pointers in xe_gt.c with local structure

[Francois Dugast]

A local structure of function pointers is used as a minimal
hardware abstraction layer to split between common and platform
specific code. This structure is initialized once with the
functions matching the platform, then it is used in the common
code with no need for switch or if/else to detect the platform.
For now only the function setup_private_ppat() is refactored.

Signed-off-by: Francois Dugast <francois.dugast at intel.com>
---
 drivers/gpu/drm/xe/xe_device_types.h |  1 +
 drivers/gpu/drm/xe/xe_gt.c           | 49 ++++++++++++++++++++++++----
 2 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 4c65598652e8..7d72fb3ff08d 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -313,6 +313,7 @@ struct xe_device {
 		u32 lvds_channel_mode;
 	} params;
 #endif
+	const struct xe_gt_platform_funcs *gt_funcs;
 };
 
 /**
diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
index daa433d0f2f5..718cd18b6421 100644
--- a/drivers/gpu/drm/xe/xe_gt.c
+++ b/drivers/gpu/drm/xe/xe_gt.c
@@ -42,6 +42,26 @@
 #include "xe_wa.h"
 #include "xe_wopcm.h"
 
+struct xe_gt_platform_funcs {
+	void (*setup_private_ppat)(struct xe_gt *gt);
+};
+
+static void mtl_setup_private_ppat(struct xe_gt *gt);
+static void pvc_setup_private_ppat(struct xe_gt *gt);
+static void tgl_setup_private_ppat(struct xe_gt *gt);
+
+static const struct xe_gt_platform_funcs mtl_funcs = {
+	.setup_private_ppat = mtl_setup_private_ppat,
+};
+
+static const struct xe_gt_platform_funcs pvc_funcs = {
+	.setup_private_ppat = pvc_setup_private_ppat,
+};
+
+static const struct xe_gt_platform_funcs tgl_funcs = {
+	.setup_private_ppat = tgl_setup_private_ppat,
+};
+
 struct xe_gt *xe_find_full_gt(struct xe_gt *gt)
 {
 	struct xe_gt *search;
@@ -161,12 +181,8 @@ static void setup_private_ppat(struct xe_gt *gt)
 {
 	struct xe_device *xe = gt_to_xe(gt);
 
-	if (xe->info.platform == XE_METEORLAKE)
-		mtl_setup_private_ppat(gt);
-	else if (xe->info.platform == XE_PVC)
-		pvc_setup_private_ppat(gt);
-	else
-		tgl_setup_private_ppat(gt);
+	if (xe->gt_funcs->setup_private_ppat)
+		xe->gt_funcs->setup_private_ppat(gt);
 }
 
 static int gt_ttm_mgr_init(struct xe_gt *gt)
@@ -380,6 +396,27 @@ int xe_gt_record_default_lrcs(struct xe_gt *gt)
 int xe_gt_init_early(struct xe_gt *gt)
 {
 	int err;
+	struct xe_device *xe = gt_to_xe(gt);
+
+	switch (xe->info.platform) {
+	case XE_METEORLAKE:
+		xe->gt_funcs = &mtl_funcs;
+		break;
+	case XE_PVC:
+		xe->gt_funcs = &pvc_funcs;
+		break;
+	case XE_ROCKETLAKE:
+	case XE_DG1:
+	case XE_DG2:
+	case XE_ALDERLAKE_S:
+	case XE_ALDERLAKE_P:
+	case XE_TIGERLAKE:
+		xe->gt_funcs = &tgl_funcs;
+		break;
+	default:
+		DRM_ERROR("Unsupported platform\n");
+		break;
+	}
 
 	xe_force_wake_init_gt(gt, gt_to_fw(gt));
 
-- 
2.25.1