drm/radeon/kms: allocate vram scratch page on 6xx+

The vram scratch was originally only used on some 7xx asics
to work around a hw bug.  Allocate the scratch page on all 6xx+
radeons and set the MC_VM_SYSTEM_APERTURE_DEFAULT_ADDR to point
to it.  We shouldn't ever hit it since we limit the system
aperture to vram or vram and AGP, but better safe than sorry.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 53 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index 1f007adc2723..75b8e004ca80 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -1137,7 +1137,7 @@ static void r600_mc_program(struct radeon_device *rdev)
 		WREG32(MC_VM_SYSTEM_APERTURE_LOW_ADDR, rdev->mc.vram_start >> 12);
 		WREG32(MC_VM_SYSTEM_APERTURE_HIGH_ADDR, rdev->mc.vram_end >> 12);
 	}
-	WREG32(MC_VM_SYSTEM_APERTURE_DEFAULT_ADDR, 0);
+	WREG32(MC_VM_SYSTEM_APERTURE_DEFAULT_ADDR, rdev->vram_scratch.gpu_addr >> 12);
 	tmp = ((rdev->mc.vram_end >> 24) & 0xFFFF) << 16;
 	tmp |= ((rdev->mc.vram_start >> 24) & 0xFFFF);
 	WREG32(MC_VM_FB_LOCATION, tmp);
@@ -1276,6 +1276,53 @@ int r600_mc_init(struct radeon_device *rdev)
 	return 0;
 }
 
+int r600_vram_scratch_init(struct radeon_device *rdev)
+{
+	int r;
+
+	if (rdev->vram_scratch.robj == NULL) {
+		r = radeon_bo_create(rdev, RADEON_GPU_PAGE_SIZE,
+				     PAGE_SIZE, true, RADEON_GEM_DOMAIN_VRAM,
+				     &rdev->vram_scratch.robj);
+		if (r) {
+			return r;
+		}
+	}
+
+	r = radeon_bo_reserve(rdev->vram_scratch.robj, false);
+	if (unlikely(r != 0))
+		return r;
+	r = radeon_bo_pin(rdev->vram_scratch.robj,
+			  RADEON_GEM_DOMAIN_VRAM, &rdev->vram_scratch.gpu_addr);
+	if (r) {
+		radeon_bo_unreserve(rdev->vram_scratch.robj);
+		return r;
+	}
+	r = radeon_bo_kmap(rdev->vram_scratch.robj,
+				(void **)&rdev->vram_scratch.ptr);
+	if (r)
+		radeon_bo_unpin(rdev->vram_scratch.robj);
+	radeon_bo_unreserve(rdev->vram_scratch.robj);
+
+	return r;
+}
+
+void r600_vram_scratch_fini(struct radeon_device *rdev)
+{
+	int r;
+
+	if (rdev->vram_scratch.robj == NULL) {
+		return;
+	}
+	r = radeon_bo_reserve(rdev->vram_scratch.robj, false);
+	if (likely(r == 0)) {
+		radeon_bo_kunmap(rdev->vram_scratch.robj);
+		radeon_bo_unpin(rdev->vram_scratch.robj);
+		radeon_bo_unreserve(rdev->vram_scratch.robj);
+	}
+	radeon_bo_unref(&rdev->vram_scratch.robj);
+}
+
 /* We doesn't check that the GPU really needs a reset we simply do the
  * reset, it's up to the caller to determine if the GPU needs one. We
  * might add an helper function to check that.
@@ -2436,6 +2483,10 @@ int r600_startup(struct radeon_device *rdev)
 		}
 	}
 
+	r = r600_vram_scratch_init(rdev);
+	if (r)
+		return r;
+
 	r600_mc_program(rdev);
 	if (rdev->flags & RADEON_IS_AGP) {
 		r600_agp_enable(rdev);
@@ -2656,6 +2707,7 @@ void r600_fini(struct radeon_device *rdev)
 	radeon_ib_pool_fini(rdev);
 	radeon_irq_kms_fini(rdev);
 	r600_pcie_gart_fini(rdev);
+	r600_vram_scratch_fini(rdev);
 	radeon_agp_fini(rdev);
 	radeon_gem_fini(rdev);
 	radeon_fence_driver_fini(rdev);