drm/amdgpu: handle CPU access for split VRAM buffers (v2)

This avoids merging them together on page fault.

v2: squash in 64-bit division fix

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 83f4930f870c..e3008d55ec77 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -529,9 +529,6 @@ static int amdgpu_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_
         case TTM_PL_TT:
                 break;
         case TTM_PL_VRAM:
-                if (mem->start == AMDGPU_BO_INVALID_OFFSET)
-                        return -EINVAL;
-
                 mem->bus.offset = mem->start << PAGE_SHIFT;
                 /* check if it's visible */
                 if ((mem->bus.offset + mem->bus.size) > adev->mc.visible_vram_size)
@@ -549,6 +546,17 @@ static void amdgpu_ttm_io_mem_free(struct ttm_bo_device *bdev, struct ttm_mem_re
 {
 }
 
+static unsigned long amdgpu_ttm_io_mem_pfn(struct ttm_buffer_object *bo,
+                                           unsigned long page_offset)
+{
+        struct drm_mm_node *mm = bo->mem.mm_node;
+        uint64_t size = mm->size;
+        unsigned long offset = page_offset;
+
+        page_offset = do_div(offset, size);
+        return (bo->mem.bus.base >> PAGE_SHIFT) + mm->start + page_offset;
+}
+
 /*
  * TTM backend functions.
  */
@@ -1064,7 +1072,7 @@ static struct ttm_bo_driver amdgpu_bo_driver = {
         .fault_reserve_notify = &amdgpu_bo_fault_reserve_notify,
         .io_mem_reserve = &amdgpu_ttm_io_mem_reserve,
         .io_mem_free = &amdgpu_ttm_io_mem_free,
-        .io_mem_pfn = ttm_bo_default_io_mem_pfn,
+        .io_mem_pfn = amdgpu_ttm_io_mem_pfn,
 };
 
 int amdgpu_ttm_init(struct amdgpu_device *adev)