[PATCH] drm/xe: Carve out wopcm portion from the stolen memory

[Nirmoy Das <nirmoy.das@xxxxxxxxx>]

Top of stolen memory is wopcm which shouldn't be accessed so remove
that portion of memory from the stolen memory.

Fixes: d8b52a02cb40 ("drm/xe: Implement stolen memory.")
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v6.8+
Signed-off-by: Nirmoy Das <nirmoy.das@xxxxxxxxx>
---
 drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c | 54 ++++++++++++++------------
 1 file changed, 30 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c b/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
index 423856cc18d4..d414421f8c13 100644
--- a/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
+++ b/drivers/gpu/drm/xe/xe_ttm_stolen_mgr.c
@@ -57,12 +57,35 @@ bool xe_ttm_stolen_cpu_access_needs_ggtt(struct xe_device *xe)
 	return GRAPHICS_VERx100(xe) < 1270 && !IS_DGFX(xe);
 }
 
+static u32 get_wopcm_size(struct xe_device *xe)
+{
+	u32 wopcm_size;
+	u64 val;
+
+	val = xe_mmio_read64_2x32(xe_root_tile_mmio(xe), STOLEN_RESERVED);
+	val = REG_FIELD_GET64(WOPCM_SIZE_MASK, val);
+
+	switch (val) {
+	case 0x5 ... 0x6:
+		val--;
+		fallthrough;
+	case 0x0 ... 0x3:
+		wopcm_size = (1U << val) * SZ_1M;
+		break;
+	default:
+		WARN(1, "Missing case wopcm_size=%llx\n", val);
+		wopcm_size = 0;
+	}
+
+	return wopcm_size;
+}
+
 static s64 detect_bar2_dgfx(struct xe_device *xe, struct xe_ttm_stolen_mgr *mgr)
 {
 	struct xe_tile *tile = xe_device_get_root_tile(xe);
 	struct xe_mmio *mmio = xe_root_tile_mmio(xe);
 	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
-	u64 stolen_size;
+	u64 stolen_size, wopcm_size;
 	u64 tile_offset;
 	u64 tile_size;
 
@@ -74,7 +97,13 @@ static s64 detect_bar2_dgfx(struct xe_device *xe, struct xe_ttm_stolen_mgr *mgr)
 	if (drm_WARN_ON(&xe->drm, tile_size < mgr->stolen_base))
 		return 0;
 
+	/* Carve out the top of DSM as it contains the reserved WOPCM region */
+	wopcm_size = get_wopcm_size(xe);
+	if (drm_WARN_ON(&xe->drm, !wopcm_size))
+		return 0;
+
 	stolen_size = tile_size - mgr->stolen_base;
+	stolen_size -= wopcm_size;
 
 	/* Verify usage fits in the actual resource available */
 	if (mgr->stolen_base + stolen_size <= pci_resource_len(pdev, LMEM_BAR))
@@ -89,29 +118,6 @@ static s64 detect_bar2_dgfx(struct xe_device *xe, struct xe_ttm_stolen_mgr *mgr)
 	return ALIGN_DOWN(stolen_size, SZ_1M);
 }
 
-static u32 get_wopcm_size(struct xe_device *xe)
-{
-	u32 wopcm_size;
-	u64 val;
-
-	val = xe_mmio_read64_2x32(xe_root_tile_mmio(xe), STOLEN_RESERVED);
-	val = REG_FIELD_GET64(WOPCM_SIZE_MASK, val);
-
-	switch (val) {
-	case 0x5 ... 0x6:
-		val--;
-		fallthrough;
-	case 0x0 ... 0x3:
-		wopcm_size = (1U << val) * SZ_1M;
-		break;
-	default:
-		WARN(1, "Missing case wopcm_size=%llx\n", val);
-		wopcm_size = 0;
-	}
-
-	return wopcm_size;
-}
-
 static u32 detect_bar2_integrated(struct xe_device *xe, struct xe_ttm_stolen_mgr *mgr)
 {
 	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
-- 
2.46.0