[PATCH 1/2] drm/amdgpu/gmc: add a way to force a particular placement for GART

[Alex Deucher <alexander.deucher@amd.com>]

We normally place GART based on the location of VRAM and the
available address space around that, but provide an option
to force a particular location for hardware that needs it.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c | 19 +++++++++++++++----
 drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h |  8 ++++++++
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
index f74a51a93ebb..d1d98488373b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
@@ -287,11 +287,22 @@ void amdgpu_gmc_gart_location(struct amdgpu_device *adev, struct amdgpu_gmc *mc)
 		mc->gart_size = max(size_bf, size_af);
 	}
 
-	if ((size_bf >= mc->gart_size && size_bf < size_af) ||
-	    (size_af < mc->gart_size))
-		mc->gart_start = 0;
-	else
+	switch (mc->gart_placement) {
+	case AMDGPU_GART_PLACEMENT_HIGH:
 		mc->gart_start = max_mc_address - mc->gart_size + 1;
+		break;
+	case AMDGPU_GART_PLACEMENT_LOW:
+		mc->gart_start = 0;
+		break;
+	case AMDGPU_GART_PLACEMENT_BEST_FIT:
+	default:
+		if ((size_bf >= mc->gart_size && size_bf < size_af) ||
+		    (size_af < mc->gart_size))
+			mc->gart_start = 0;
+		else
+			mc->gart_start = max_mc_address - mc->gart_size + 1;
+		break;
+	}
 
 	mc->gart_start &= ~(four_gb - 1);
 	mc->gart_end = mc->gart_start + mc->gart_size - 1;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
index dd0ede75e5d7..fcef057b9213 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
@@ -199,6 +199,12 @@ struct amdgpu_mem_partition_info {
 
 #define INVALID_PFN    -1
 
+enum amdgpu_gart_placement {
+	AMDGPU_GART_PLACEMENT_BEST_FIT = 0,
+	AMDGPU_GART_PLACEMENT_HIGH,
+	AMDGPU_GART_PLACEMENT_LOW,
+};
+
 struct amdgpu_gmc {
 	/* FB's physical address in MMIO space (for CPU to
 	 * map FB). This is different compared to the agp/
@@ -339,6 +345,8 @@ struct amdgpu_gmc {
 	bool flush_tlb_needs_extra_type_0;
 	bool flush_tlb_needs_extra_type_2;
 	bool flush_pasid_uses_kiq;
+
+	enum amdgpu_gart_placement gart_placement;
 };
 
 #define amdgpu_gmc_emit_flush_gpu_tlb(r, vmid, addr) (r)->adev->gmc.gmc_funcs->emit_flush_gpu_tlb((r), (vmid), (addr))
-- 
2.41.0