[PATCH 2/2] drm/amdgpu: access stolen VRAM directly on CZ

[Christian König]

From: Christian König <christian.koenig at amd.com>

We don't need to use the PCI BAR on APUs. This allows us to access
the full VRAM directly without being limited by the BAR size.

Signed-off-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
index f7372d3..0323f5d 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c
@@ -462,9 +462,16 @@ static int gmc_v8_0_mc_init(struct amdgpu_device *adev)
 	/* size in MB on si */
 	adev->mc.mc_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
 	adev->mc.real_vram_size = RREG32(mmCONFIG_MEMSIZE) * 1024ULL * 1024ULL;
-	adev->mc.visible_vram_size = adev->mc.aper_size;
+
+#ifdef CONFIG_X86_64
+	if (adev->flags & AMD_IS_APU) {
+		adev->mc.aper_base = RREG32(mmMC_VM_FB_OFFSET) << 22ULL;
+		adev->mc.aper_size = adev->mc.real_vram_size;
+	}
+#endif
 
 	/* In case the PCI BAR is larger than the actual amount of vram */
+	adev->mc.visible_vram_size = adev->mc.aper_size;
 	if (adev->mc.visible_vram_size > adev->mc.real_vram_size)
 		adev->mc.visible_vram_size = adev->mc.real_vram_size;
 
-- 
2.7.4