[PATCH 8/8] drm/amdgpu: add support for exporting VRAM using DMA-buf

Christian König
2018-03-25T11:01:24Z

We should be able to do this now after checking all the prerequisites.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c | 44 +++++++++++---
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h | 9 +++
drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 91 ++++++++++++++++++++++++++++
3 files changed, 135 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
index 133596df0775..86d983a0678b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
@@ -197,23 +197,44 @@ amdgpu_gem_map_dma_buf(struct dma_buf_attachment *attach,
} else {
/* move buffer into GTT */
struct ttm_operation_ctx ctx = { false, false };
+ unsigned domains = AMDGPU_GEM_DOMAIN_GTT;

- amdgpu_ttm_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_GTT);
+ if (bo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM &&
+ attach->peer2peer) {
+ bo->flags |= AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
+ domains |= AMDGPU_GEM_DOMAIN_VRAM;
+ }
+ amdgpu_ttm_placement_from_domain(bo, domains);
r = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
if (r)
goto error_unreserve;
}

- sgt = drm_prime_pages_to_sg(bo->tbo.ttm->pages, bo->tbo.num_pages);
- if (IS_ERR(sgt)) {
- r = PTR_ERR(sgt);
+ switch (bo->tbo.mem.mem_type) {
+ case TTM_PL_TT:
+ sgt = drm_prime_pages_to_sg(bo->tbo.ttm->pages,
+ bo->tbo.num_pages);
+ if (IS_ERR(sgt)) {
+ r = PTR_ERR(sgt);
+ goto error_unreserve;
+ }
+
+ if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
+ DMA_ATTR_SKIP_CPU_SYNC))
+ goto error_free;
+ break;
+
+ case TTM_PL_VRAM:
+ r = amdgpu_vram_mgr_alloc_sgt(adev, &bo->tbo.mem, attach->dev,
+ dir, &sgt);
+ if (r)
+ goto error_unreserve;
+ break;
+ default:
+ r = -EINVAL;
goto error_unreserve;
}

- if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
- DMA_ATTR_SKIP_CPU_SYNC))
- goto error_free;
-
if (attach->dev->driver != adev->dev->driver)
bo->prime_shared_count++;

@@ -254,10 +275,15 @@ static void amdgpu_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
if (!attach->invalidate)
amdgpu_bo_unreserve(bo);

- if (sgt) {
+ if (!sgt)
+ return;
+
+ if (sgt->sgl->page_link) {
dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
sg_free_table(sgt);
kfree(sgt);
+ } else {
+ amdgpu_vram_mgr_free_sgt(adev, attach->dev, dir, sgt);
}
}

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
index 6ea7de863041..b483900abed2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
@@ -73,6 +73,15 @@ bool amdgpu_gtt_mgr_has_gart_addr(struct ttm_mem_reg *mem);
uint64_t amdgpu_gtt_mgr_usage(struct ttm_mem_type_manager *man);
int amdgpu_gtt_mgr_recover(struct ttm_mem_type_manager *man);

+int amdgpu_vram_mgr_alloc_sgt(struct amdgpu_device *adev,
+ struct ttm_mem_reg *mem,
+ struct device *dev,
+ enum dma_data_direction dir,
+ struct sg_table **sgt);
+void amdgpu_vram_mgr_free_sgt(struct amdgpu_device *adev,
+ struct device *dev,
+ enum dma_data_direction dir,
+ struct sg_table *sgt);
uint64_t amdgpu_vram_mgr_usage(struct ttm_mem_type_manager *man);
uint64_t amdgpu_vram_mgr_vis_usage(struct ttm_mem_type_manager *man);

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
index 9aca653bec07..eb8f75525a81 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
@@ -233,6 +233,97 @@ static void amdgpu_vram_mgr_del(struct ttm_mem_type_manager *man,
mem->mm_node = NULL;
}

+/**
+ * amdgpu_vram_mgr_alloc_sgt - allocate and fill a sg table
+ *
+ * @adev: amdgpu device pointer
+ * @mem: TTM memory object
+ * @dev: the other device
+ * @dir: dma direction
+ * @sgt: resulting sg table
+ *
+ * Allocate and fill a sg table from a VRAM allocation.
+ */
+int amdgpu_vram_mgr_alloc_sgt(struct amdgpu_device *adev,
+ struct ttm_mem_reg *mem,
+ struct device *dev,
+ enum dma_data_direction dir,
+ struct sg_table **sgt)
+{
+ struct drm_mm_node *node = mem->mm_node;
+ struct scatterlist *sg;
+ int num_entries;
+ int i, r;
+
+ *sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
+ if (!*sgt)
+ return -ENOMEM;
+
+ num_entries = DIV_ROUND_UP(mem->num_pages, node->size);
+ r = sg_alloc_table(*sgt, num_entries, GFP_KERNEL);
+ if (r)
+ goto error_free;
+
+ for_each_sg((*sgt)->sgl, sg, num_entries, i)
+ sg->length = 0;
+
+ for_each_sg((*sgt)->sgl, sg, num_entries, i) {
+ phys_addr_t phys = (node->start << PAGE_SHIFT) +
+ adev->gmc.aper_base;
+ size_t size = node->size << PAGE_SHIFT;
+ dma_addr_t addr;
+
+ ++node;
+ addr = dma_map_resource(dev, phys, size, dir,
+ DMA_ATTR_SKIP_CPU_SYNC);
+ r = dma_mapping_error(dev, addr);
+ if (r)
+ goto error_unmap;
+
+ sg_set_dma_addr(sg, addr, size, 0);
+ }
+ return 0;
+
+error_unmap:
+ for_each_sg((*sgt)->sgl, sg, num_entries, i) {
+ if (!sg->length)
+ continue;
+
+ dma_unmap_resource(dev, sg->dma_address,
+ sg->length, dir,
+ DMA_ATTR_SKIP_CPU_SYNC);
+ }
+ sg_free_table(*sgt);
+
+error_free:
+ kfree(*sgt);
+ return r;
+}
+
+/**
+ * amdgpu_vram_mgr_alloc_sgt - allocate and fill a sg table
+ *
+ * @adev: amdgpu device pointer
+ * @sgt: sg table to free
+ *
+ * Free a previously allocate sg table.
+ */
+void amdgpu_vram_mgr_free_sgt(struct amdgpu_device *adev,
+ struct device *dev,
+ enum dma_data_direction dir,
+ struct sg_table *sgt)
+{
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(sgt->sgl, sg, sgt->nents, i)
+ dma_unmap_resource(dev, sg->dma_address,
+ sg->length, dir,
+ DMA_ATTR_SKIP_CPU_SYNC);
+ sg_free_table(sgt);
+ kfree(sgt);
+}
+
/**
* amdgpu_vram_mgr_usage - how many bytes are used in this domain
*
--
2.14.1