Commit 09052fc3 authored by Samuel Li's avatar Samuel Li Committed by Alex Deucher
Browse files

drm/amdgpu: Move to gtt before cpu accesses dma buf. 

To improve cpu read performance. This is implemented for APUs currently.

v2: Adapt to change https://lists.freedesktop.org/archives/amd-gfx/2017-October/015174.html


v3: Adapt to change "forward begin_cpu_access callback to drivers"
v4: Instead of v3, reuse drm_gem dmabuf_ops here. Also some minor fixes as suggested.
v5: only set dma_buf ops when it is valid (Samuel)

Signed-off-by: default avatarSamuel Li <Samuel.Li@amd.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 6e227308

drivers/gpu/drm/amd/amdgpu/amdgpu.h

+2 −0
Original line number Diff line number Diff line
@@ -418,6 +418,8 @@ amdgpu_gem_prime_import_sg_table(struct drm_device *dev, 
struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,

					struct drm_gem_object *gobj,

					int flags);

struct drm_gem_object *amdgpu_gem_prime_import(struct drm_device *dev,

					    struct dma_buf *dma_buf);

int amdgpu_gem_prime_pin(struct drm_gem_object *obj);

void amdgpu_gem_prime_unpin(struct drm_gem_object *obj);

struct reservation_object *amdgpu_gem_prime_res_obj(struct drm_gem_object *);

drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

+1 −1
Original line number Diff line number Diff line
@@ -870,7 +870,7 @@ static struct drm_driver kms_driver = { 
	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,

	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,

	.gem_prime_export = amdgpu_gem_prime_export,

	.gem_prime_import = drm_gem_prime_import,

	.gem_prime_import = amdgpu_gem_prime_import,

	.gem_prime_pin = amdgpu_gem_prime_pin,

	.gem_prime_unpin = amdgpu_gem_prime_unpin,

	.gem_prime_res_obj = amdgpu_gem_prime_res_obj,

drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c

+69 −1
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <drm/drmP.h>



#include "amdgpu.h"

#include "amdgpu_display.h"

#include <drm/amdgpu_drm.h>

#include <linux/dma-buf.h>
@@ -164,6 +165,50 @@ struct reservation_object *amdgpu_gem_prime_res_obj(struct drm_gem_object *obj) 
	return bo->tbo.resv;

}



static int amdgpu_gem_begin_cpu_access(struct dma_buf *dma_buf,

				       enum dma_data_direction direction)

{

	struct amdgpu_bo *bo = gem_to_amdgpu_bo(dma_buf->priv);

	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);

	struct ttm_operation_ctx ctx = { true, false };

	u32 domain = amdgpu_display_framebuffer_domains(adev);

	int ret;

	bool reads = (direction == DMA_BIDIRECTIONAL ||

		      direction == DMA_FROM_DEVICE);



	if (!reads || !(domain & AMDGPU_GEM_DOMAIN_GTT))

		return 0;



	/* move to gtt */

	ret = amdgpu_bo_reserve(bo, false);

	if (unlikely(ret != 0))

		return ret;



	if (!bo->pin_count && (bo->allowed_domains & AMDGPU_GEM_DOMAIN_GTT)) {

		amdgpu_ttm_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_GTT);

		ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);

	}



	amdgpu_bo_unreserve(bo);

	return ret;

}



static const struct dma_buf_ops amdgpu_dmabuf_ops = {

	.attach = drm_gem_map_attach,

	.detach = drm_gem_map_detach,

	.map_dma_buf = drm_gem_map_dma_buf,

	.unmap_dma_buf = drm_gem_unmap_dma_buf,

	.release = drm_gem_dmabuf_release,

	.begin_cpu_access = amdgpu_gem_begin_cpu_access,

	.map = drm_gem_dmabuf_kmap,

	.map_atomic = drm_gem_dmabuf_kmap_atomic,

	.unmap = drm_gem_dmabuf_kunmap,

	.unmap_atomic = drm_gem_dmabuf_kunmap_atomic,

	.mmap = drm_gem_dmabuf_mmap,

	.vmap = drm_gem_dmabuf_vmap,

	.vunmap = drm_gem_dmabuf_vunmap,

};



struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,

					struct drm_gem_object *gobj,

					int flags)
@@ -176,7 +221,30 @@ struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev, 
		return ERR_PTR(-EPERM);



	buf = drm_gem_prime_export(dev, gobj, flags);

	if (!IS_ERR(buf))

	if (!IS_ERR(buf)) {

		buf->file->f_mapping = dev->anon_inode->i_mapping;

		buf->ops = &amdgpu_dmabuf_ops;

	}



	return buf;

}



struct drm_gem_object *amdgpu_gem_prime_import(struct drm_device *dev,

					    struct dma_buf *dma_buf)

{

	struct drm_gem_object *obj;



	if (dma_buf->ops == &amdgpu_dmabuf_ops) {

		obj = dma_buf->priv;

		if (obj->dev == dev) {

			/*

			 * Importing dmabuf exported from out own gem increases

			 * refcount on gem itself instead of f_count of dmabuf.

			 */

			drm_gem_object_get(obj);

			return obj;

		}

	}



	return drm_gem_prime_import(dev, dma_buf);

}

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