[Intel-gfx] [RFC PATCH] drm/i915: don't treat small BAR as an error with CSS

[Nirmoy Das]

Determine lmem_size using ADDR_RANGE register so that module
load on platfrom with small bar with css  works.

Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
---
I once reserved a dg2 machine with small bar and module load failed on
it. I can't find that machine anymore hence sending this as RFC.

 drivers/gpu/drm/i915/gt/intel_region_lmem.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_region_lmem.c b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
index f5111c0a0060..a55eecac104e 100644
--- a/drivers/gpu/drm/i915/gt/intel_region_lmem.c
+++ b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
@@ -100,10 +100,19 @@ static struct intel_memory_region *setup_lmem(struct intel_gt *gt)
 	if (!IS_DGFX(i915))
 		return ERR_PTR(-ENODEV);
 
+	if (IS_DG1(uncore->i915)) {
+		lmem_size = pci_resource_len(pdev, 2);
+	} else {
+		resource_size_t lmem_range;
+
+		lmem_range = intel_gt_read_register(&i915->gt0, XEHPSDV_TILE0_ADDR_RANGE) & 0xFFFF;
+		lmem_size = lmem_range >> XEHPSDV_TILE_LMEM_RANGE_SHIFT;
+		lmem_size *= SZ_1G;
+	}
+
 	if (HAS_FLAT_CCS(i915)) {
 		u64 tile_stolen, flat_ccs_base;
 
-		lmem_size = pci_resource_len(pdev, 2);
 		flat_ccs_base = intel_gt_read_register(gt, XEHPSDV_FLAT_CCS_BASE_ADDR);
 		flat_ccs_base = (flat_ccs_base >> XEHPSDV_CCS_BASE_SHIFT) * SZ_64K;
 
-- 
2.35.1