Commit 6e6db272 authored by Christian König's avatar Christian König
Browse files

drm/amdgpu: add independent DMA-buf export v8 



Add an DMA-buf export implementation independent of the DRM helpers.

This not only avoids the caching of DMA-buf mappings, but also
allows us to use the new dynamic locking approach.

This is also a prerequisite of unpinned DMA-buf handling.

v2: fix unintended recursion, remove debugging leftovers
v3: split out from unpinned DMA-buf work
v4: rebase on top of new no_sgt_cache flag
v5: fix some warnings by including amdgpu_dma_buf.h
v6: fix locking for non amdgpu exports
v7: rebased on new DMA-buf locking patch
v8: drop extra include

Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/337949/
parent 955a72ce

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

+96 −76
Original line number Diff line number Diff line
@@ -34,26 +34,11 @@ 
#include "amdgpu.h"

#include "amdgpu_display.h"

#include "amdgpu_gem.h"

#include "amdgpu_dma_buf.h"

#include <drm/amdgpu_drm.h>

#include <linux/dma-buf.h>

#include <linux/dma-fence-array.h>



/**

 * amdgpu_gem_prime_get_sg_table - &drm_driver.gem_prime_get_sg_table

 * implementation

 * @obj: GEM buffer object (BO)

 *

 * Returns:

 * A scatter/gather table for the pinned pages of the BO's memory.

 */

struct sg_table *amdgpu_gem_prime_get_sg_table(struct drm_gem_object *obj)

{

	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);

	int npages = bo->tbo.num_pages;



	return drm_prime_pages_to_sg(bo->tbo.ttm->pages, npages);

}



/**

 * amdgpu_gem_prime_vmap - &dma_buf_ops.vmap implementation

 * @obj: GEM BO
@@ -179,35 +164,28 @@ err_fences_put: 
}



/**

 * amdgpu_dma_buf_map_attach - &dma_buf_ops.attach implementation

 * @dma_buf: Shared DMA buffer

 * @attach: DMA-buf attachment

 * amdgpu_dma_buf_attach - &dma_buf_ops.attach implementation

 *

 * Makes sure that the shared DMA buffer can be accessed by the target device.

 * For now, simply pins it to the GTT domain, where it should be accessible by

 * all DMA devices.

 * @dmabuf: DMA-buf where we attach to

 * @attach: attachment to add

 *

 * Returns:

 * 0 on success or a negative error code on failure.

 * Add the attachment as user to the exported DMA-buf.

 */

static int amdgpu_dma_buf_map_attach(struct dma_buf *dma_buf,

static int amdgpu_dma_buf_attach(struct dma_buf *dmabuf,

				 struct dma_buf_attachment *attach)

{

	struct drm_gem_object *obj = dma_buf->priv;

	struct drm_gem_object *obj = dmabuf->priv;

	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);

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

	long r;

	int r;



	r = drm_gem_map_attach(dma_buf, attach);

	if (r)

		return r;

	if (attach->dev->driver == adev->dev->driver)

		return 0;



	r = amdgpu_bo_reserve(bo, false);

	if (unlikely(r != 0))

		goto error_detach;



		return r;



	if (attach->dev->driver != adev->dev->driver) {

	/*

	 * We only create shared fences for internal use, but importers

	 * of the dmabuf rely on exclusive fences for implicitly
@@ -218,53 +196,94 @@ static int amdgpu_dma_buf_map_attach(struct dma_buf *dma_buf, 
	 */

	r = __dma_resv_make_exclusive(bo->tbo.base.resv);

	if (r)

			goto error_unreserve;

		return r;



	bo->prime_shared_count++;

	amdgpu_bo_unreserve(bo);

	return 0;

}



/**

 * amdgpu_dma_buf_detach - &dma_buf_ops.detach implementation

 *

 * @dmabuf: DMA-buf where we remove the attachment from

 * @attach: the attachment to remove

 *

 * Called when an attachment is removed from the DMA-buf.

 */

static void amdgpu_dma_buf_detach(struct dma_buf *dmabuf,

				  struct dma_buf_attachment *attach)

{

	struct drm_gem_object *obj = dmabuf->priv;

	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);

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



	if (attach->dev->driver != adev->dev->driver && bo->prime_shared_count)

		bo->prime_shared_count--;

}



	/* pin buffer into GTT */

/**

 * amdgpu_dma_buf_map - &dma_buf_ops.map_dma_buf implementation

 * @attach: DMA-buf attachment

 * @dir: DMA direction

 *

 * Makes sure that the shared DMA buffer can be accessed by the target device.

 * For now, simply pins it to the GTT domain, where it should be accessible by

 * all DMA devices.

 *

 * Returns:

 * sg_table filled with the DMA addresses to use or ERR_PRT with negative error

 * code.

 */

static struct sg_table *amdgpu_dma_buf_map(struct dma_buf_attachment *attach,

					   enum dma_data_direction dir)

{

	struct dma_buf *dma_buf = attach->dmabuf;

	struct drm_gem_object *obj = dma_buf->priv;

	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);

	struct sg_table *sgt;

	long r;



	r = amdgpu_bo_pin(bo, AMDGPU_GEM_DOMAIN_GTT);

	if (r)

		goto error_unreserve;

		return ERR_PTR(r);



	if (attach->dev->driver != adev->dev->driver)

		bo->prime_shared_count++;

	sgt = drm_prime_pages_to_sg(bo->tbo.ttm->pages, bo->tbo.num_pages);

	if (IS_ERR(sgt))

		return sgt;



error_unreserve:

	amdgpu_bo_unreserve(bo);

	if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,

			      DMA_ATTR_SKIP_CPU_SYNC))

		goto error_free;



error_detach:

	if (r)

		drm_gem_map_detach(dma_buf, attach);

	return r;

	return sgt;



error_free:

	sg_free_table(sgt);

	kfree(sgt);

	return ERR_PTR(-ENOMEM);

}



/**

 * amdgpu_dma_buf_map_detach - &dma_buf_ops.detach implementation

 * @dma_buf: Shared DMA buffer

 * amdgpu_dma_buf_unmap - &dma_buf_ops.unmap_dma_buf implementation

 * @attach: DMA-buf attachment

 * @sgt: sg_table to unmap

 * @dir: DMA direction

 *

 * This is called when a shared DMA buffer no longer needs to be accessible by

 * another device. For now, simply unpins the buffer from GTT.

 */

static void amdgpu_dma_buf_map_detach(struct dma_buf *dma_buf,

				      struct dma_buf_attachment *attach)

static void amdgpu_dma_buf_unmap(struct dma_buf_attachment *attach,

				 struct sg_table *sgt,

				 enum dma_data_direction dir)

{

	struct drm_gem_object *obj = dma_buf->priv;

	struct drm_gem_object *obj = attach->dmabuf->priv;

	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);

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

	int ret = 0;



	ret = amdgpu_bo_reserve(bo, true);

	if (unlikely(ret != 0))

		goto error;



	dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);

	sg_free_table(sgt);

	kfree(sgt);

	amdgpu_bo_unpin(bo);

	if (attach->dev->driver != adev->dev->driver && bo->prime_shared_count)

		bo->prime_shared_count--;

	amdgpu_bo_unreserve(bo);



error:

	drm_gem_map_detach(dma_buf, attach);

}



/**
@@ -308,10 +327,11 @@ static int amdgpu_dma_buf_begin_cpu_access(struct dma_buf *dma_buf, 
}



const struct dma_buf_ops amdgpu_dmabuf_ops = {

	.attach = amdgpu_dma_buf_map_attach,

	.detach = amdgpu_dma_buf_map_detach,

	.map_dma_buf = drm_gem_map_dma_buf,

	.unmap_dma_buf = drm_gem_unmap_dma_buf,

	.dynamic_mapping = true,

	.attach = amdgpu_dma_buf_attach,

	.detach = amdgpu_dma_buf_detach,

	.map_dma_buf = amdgpu_dma_buf_map,

	.unmap_dma_buf = amdgpu_dma_buf_unmap,

	.release = drm_gem_dmabuf_release,

	.begin_cpu_access = amdgpu_dma_buf_begin_cpu_access,

	.mmap = drm_gem_dmabuf_mmap,

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

+0 −1
Original line number Diff line number Diff line
@@ -25,7 +25,6 @@ 


#include <drm/drm_gem.h>



struct sg_table *amdgpu_gem_prime_get_sg_table(struct drm_gem_object *obj);

struct drm_gem_object *

amdgpu_gem_prime_import_sg_table(struct drm_device *dev,

				 struct dma_buf_attachment *attach,

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

+0 −1
Original line number Diff line number Diff line
@@ -1445,7 +1445,6 @@ static struct drm_driver kms_driver = { 
	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,

	.gem_prime_export = amdgpu_gem_prime_export,

	.gem_prime_import = amdgpu_gem_prime_import,

	.gem_prime_get_sg_table = amdgpu_gem_prime_get_sg_table,

	.gem_prime_import_sg_table = amdgpu_gem_prime_import_sg_table,

	.gem_prime_vmap = amdgpu_gem_prime_vmap,

	.gem_prime_vunmap = amdgpu_gem_prime_vunmap,

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