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/*
* Copyright 2019 Advanced Micro Devices, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* based on nouveau_prime.c
*
* Authors: Alex Deucher
*/
/**
* DOC: PRIME Buffer Sharing
*
* The following callback implementations are used for :ref:`sharing GEM buffer
* objects between different devices via PRIME <prime_buffer_sharing>`.
*/
#include "amdgpu.h"
#include "amdgpu_display.h"
#include "amdgpu_gem.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
*
* Sets up an in-kernel virtual mapping of the BO's memory.
*
* Returns:
* The virtual address of the mapping or an error pointer.
*/
void *amdgpu_gem_prime_vmap(struct drm_gem_object *obj)
{
struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
int ret;
ret = ttm_bo_kmap(&bo->tbo, 0, bo->tbo.num_pages,
&bo->dma_buf_vmap);
if (ret)
return ERR_PTR(ret);
return bo->dma_buf_vmap.virtual;
}
/**
* amdgpu_gem_prime_vunmap - &dma_buf_ops.vunmap implementation
* @obj: GEM BO
* @vaddr: Virtual address (unused)
*
* Tears down the in-kernel virtual mapping of the BO's memory.
*/
void amdgpu_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
{
struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
ttm_bo_kunmap(&bo->dma_buf_vmap);
}
/**
* amdgpu_gem_prime_mmap - &drm_driver.gem_prime_mmap implementation
* @obj: GEM BO
* @vma: Virtual memory area
*
* Sets up a userspace mapping of the BO's memory in the given
* virtual memory area.
*
* Returns:
* 0 on success or a negative error code on failure.
*/
int amdgpu_gem_prime_mmap(struct drm_gem_object *obj,
struct vm_area_struct *vma)
{
struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
unsigned asize = amdgpu_bo_size(bo);
int ret;
if (!vma->vm_file)
return -ENODEV;
if (adev == NULL)
return -ENODEV;
/* Check for valid size. */
if (asize < vma->vm_end - vma->vm_start)
return -EINVAL;
if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm) ||
(bo->flags & AMDGPU_GEM_CREATE_NO_CPU_ACCESS)) {
return -EPERM;
}
vma->vm_pgoff += amdgpu_bo_mmap_offset(bo) >> PAGE_SHIFT;
/* prime mmap does not need to check access, so allow here */
ret = drm_vma_node_allow(&obj->vma_node, vma->vm_file->private_data);
if (ret)
return ret;
ret = ttm_bo_mmap(vma->vm_file, vma, &adev->mman.bdev);
drm_vma_node_revoke(&obj->vma_node, vma->vm_file->private_data);
return ret;
}
static int
__dma_resv_make_exclusive(struct dma_resv *obj)
{
struct dma_fence **fences;
unsigned int count;
int r;
if (!dma_resv_get_list(obj)) /* no shared fences to convert */
return 0;
r = dma_resv_get_fences_rcu(obj, NULL, &count, &fences);
if (r)
return r;
if (count == 0) {
/* Now that was unexpected. */
} else if (count == 1) {
dma_resv_add_excl_fence(obj, fences[0]);
dma_fence_put(fences[0]);
kfree(fences);
} else {
struct dma_fence_array *array;
array = dma_fence_array_create(count, fences,
dma_fence_context_alloc(1), 0,
false);
if (!array)
goto err_fences_put;
dma_resv_add_excl_fence(obj, &array->base);
dma_fence_put(&array->base);
}
return 0;
err_fences_put:
while (count--)
dma_fence_put(fences[count]);
kfree(fences);
return -ENOMEM;
}
/**
* amdgpu_dma_buf_map_attach - &dma_buf_ops.attach implementation
* @dma_buf: Shared DMA buffer
* @attach: DMA-buf attachment
*
* 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:
* 0 on success or a negative error code on failure.
*/
static int amdgpu_dma_buf_map_attach(struct dma_buf *dma_buf,
struct dma_buf_attachment *attach)
{
struct drm_gem_object *obj = dma_buf->priv;
struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
long r;
r = drm_gem_map_attach(dma_buf, attach);
if (r)
return r;
r = amdgpu_bo_reserve(bo, false);
if (unlikely(r != 0))
goto error_detach;
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
* tracking write hazards. As any of the current fences may
* correspond to a write, we need to convert all existing
* fences on the reservation object into a single exclusive
* fence.
*/
r = __dma_resv_make_exclusive(bo->tbo.base.resv);
if (r)
goto error_unreserve;
}
/* pin buffer into GTT */
r = amdgpu_bo_pin(bo, AMDGPU_GEM_DOMAIN_GTT);
if (r)
goto error_unreserve;
if (attach->dev->driver != adev->dev->driver)
bo->prime_shared_count++;
error_unreserve:
amdgpu_bo_unreserve(bo);
error_detach:
if (r)
drm_gem_map_detach(dma_buf, attach);
return r;
}
/**
* amdgpu_dma_buf_map_detach - &dma_buf_ops.detach implementation
* @dma_buf: Shared DMA buffer
* @attach: DMA-buf attachment
*
* 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)
{
struct drm_gem_object *obj = dma_buf->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;
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);
}
/**
* amdgpu_dma_buf_begin_cpu_access - &dma_buf_ops.begin_cpu_access implementation
* @dma_buf: Shared DMA buffer
* @direction: Direction of DMA transfer
*
* This is called before CPU access to the shared DMA buffer's memory. If it's
* a read access, the buffer is moved to the GTT domain if possible, for optimal
* CPU read performance.
*
* Returns:
* 0 on success or a negative error code on failure.
*/
static int amdgpu_dma_buf_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_supported_domains(adev, bo->flags);
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_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_GTT);
ret = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
}
amdgpu_bo_unreserve(bo);
return ret;
}
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,
.release = drm_gem_dmabuf_release,
.begin_cpu_access = amdgpu_dma_buf_begin_cpu_access,
.mmap = drm_gem_dmabuf_mmap,
.vmap = drm_gem_dmabuf_vmap,
.vunmap = drm_gem_dmabuf_vunmap,
};
/**
* amdgpu_gem_prime_export - &drm_driver.gem_prime_export implementation
* @dev: DRM device
* @gobj: GEM BO
* @flags: Flags such as DRM_CLOEXEC and DRM_RDWR.
*
* The main work is done by the &drm_gem_prime_export helper.
*
* Returns:
* Shared DMA buffer representing the GEM BO from the given device.
*/
struct dma_buf *amdgpu_gem_prime_export(struct drm_gem_object *gobj,
int flags)
{
struct amdgpu_bo *bo = gem_to_amdgpu_bo(gobj);
struct dma_buf *buf;
if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm) ||
bo->flags & AMDGPU_GEM_CREATE_VM_ALWAYS_VALID)
return ERR_PTR(-EPERM);
buf = drm_gem_prime_export(gobj, flags);
if (!IS_ERR(buf)) {
buf->file->f_mapping = gobj->dev->anon_inode->i_mapping;
buf->ops = &amdgpu_dmabuf_ops;
}
return buf;
}
/**
* amdgpu_gem_prime_import_sg_table - &drm_driver.gem_prime_import_sg_table
* implementation
* @dev: DRM device
* @attach: DMA-buf attachment
* @sg: Scatter/gather table
*
* Imports shared DMA buffer memory exported by another device.
*
* Returns:
* A new GEM BO of the given DRM device, representing the memory
* described by the given DMA-buf attachment and scatter/gather table.
*/
struct drm_gem_object *
amdgpu_gem_prime_import_sg_table(struct drm_device *dev,
struct dma_buf_attachment *attach,
struct sg_table *sg)
{
struct dma_resv *resv = attach->dmabuf->resv;
struct amdgpu_device *adev = dev->dev_private;
struct amdgpu_bo *bo;
struct amdgpu_bo_param bp;
int ret;
memset(&bp, 0, sizeof(bp));
bp.size = attach->dmabuf->size;
bp.byte_align = PAGE_SIZE;
bp.domain = AMDGPU_GEM_DOMAIN_CPU;
bp.flags = 0;
bp.type = ttm_bo_type_sg;
bp.resv = resv;
dma_resv_lock(resv, NULL);
ret = amdgpu_bo_create(adev, &bp, &bo);
if (ret)
goto error;
bo->tbo.sg = sg;
bo->tbo.ttm->sg = sg;
bo->allowed_domains = AMDGPU_GEM_DOMAIN_GTT;
bo->preferred_domains = AMDGPU_GEM_DOMAIN_GTT;
if (attach->dmabuf->ops != &amdgpu_dmabuf_ops)
bo->prime_shared_count = 1;
dma_resv_unlock(resv);
return &bo->tbo.base;
error:
dma_resv_unlock(resv);
return ERR_PTR(ret);
}
/**
* amdgpu_gem_prime_import - &drm_driver.gem_prime_import implementation
* @dev: DRM device
* @dma_buf: Shared DMA buffer
*
* The main work is done by the &drm_gem_prime_import helper, which in turn
* uses &amdgpu_gem_prime_import_sg_table.
*
* Returns:
* GEM BO representing the shared DMA buffer for the given device.
*/
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);
}