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drm/tegra: Implement correct DMA-BUF semantics

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DMA-BUF requires that each device that accesses a DMA-BUF attaches to it
separately. To do so the host1x_bo_pin() and host1x_bo_unpin() functions
need to be reimplemented so that they can return a mapping, which either
represents an attachment or a map of the driver's own GEM object.

Bug 200768479

Signed-off-by: Thierry Reding <treding@nvidia.com>
Change-Id: Ia380b7dcc371ce47f5f35d44a60fbd6b4ab9d636
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2596398
(cherry picked from commit 28960586000fca025689edfd45645ab28e497bca)
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2620137
Tested-by: Jonathan Hunter <jonathanh@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
Reviewed-by: Jonathan Hunter <jonathanh@nvidia.com>
Reviewed-by: svc_kernel_abi <svc_kernel_abi@nvidia.com>
Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit
This commit is contained in:
Thierry Reding
2021-09-09 15:51:24 +02:00
committed by Laxman Dewangan
parent 65450ce220
commit 756aa327f1
6 changed files with 176 additions and 159 deletions
Download Patch File Download Diff File Expand all files Collapse all files

162
drivers/gpu/drm/tegra/gem.c
View File

@@ -21,6 +21,26 @@
#include "drm.h"
#include "gem.h"
static unsigned int __sgt_dma_count_chunks(struct sg_table *sgt)
{
dma_addr_t next = ~(dma_addr_t)0;
unsigned int count = 0, i;
struct scatterlist *s;
for_each_sg(sgt->sgl, s, sgt->nents, i) {
/* sg_dma_address(s) is only valid for entries that have sg_dma_len(s) != 0. */
if (!sg_dma_len(s))
continue;
if (sg_dma_address(s) != next) {
next = sg_dma_address(s) + sg_dma_len(s);
count++;
}
}
return count;
}
static void tegra_bo_put(struct host1x_bo *bo)
{
struct tegra_bo *obj = host1x_to_tegra_bo(bo);
@@ -28,79 +48,64 @@ static void tegra_bo_put(struct host1x_bo *bo)
drm_gem_object_put(&obj->gem);
}
/* XXX move this into lib/scatterlist.c? */
static int sg_alloc_table_from_sg(struct sg_table *sgt, struct scatterlist *sg,
unsigned int nents, gfp_t gfp_mask)
{
struct scatterlist *dst;
unsigned int i;
int err;
err = sg_alloc_table(sgt, nents, gfp_mask);
if (err < 0)
return err;
dst = sgt->sgl;
for (i = 0; i < nents; i++) {
sg_set_page(dst, sg_page(sg), sg->length, 0);
dst = sg_next(dst);
sg = sg_next(sg);
}
return 0;
}
static struct sg_table *tegra_bo_pin(struct device *dev, struct host1x_bo *bo,
dma_addr_t *phys)
static struct host1x_bo_mapping *tegra_bo_pin(struct device *dev, struct host1x_bo *bo,
enum dma_data_direction direction)
{
struct tegra_bo *obj = host1x_to_tegra_bo(bo);
struct sg_table *sgt;
struct drm_gem_object *gem = &obj->gem;
struct host1x_bo_mapping *map;
int err;
map = kzalloc(sizeof(*map), GFP_KERNEL);
if (!map)
return ERR_PTR(-ENOMEM);
map->bo = host1x_bo_get(bo);
map->direction = direction;
map->dev = dev;
/*
* If we've manually mapped the buffer object through the IOMMU, make
* sure to return the IOVA address of our mapping.
*
* Similarly, for buffers that have been allocated by the DMA API the
* physical address can be used for devices that are not attached to
* an IOMMU. For these devices, callers must pass a valid pointer via
* the @phys argument.
*
* Imported buffers were also already mapped at import time, so the
* existing mapping can be reused.
* Imported buffers need special treatment to satisfy the semantics of DMA-BUF.
*/
if (phys) {
*phys = obj->iova;
return NULL;
if (gem->import_attach) {
struct dma_buf *buf = gem->import_attach->dmabuf;
map->attach = dma_buf_attach(buf, dev);
if (IS_ERR(map->attach)) {
err = PTR_ERR(map->attach);
goto free;
}
map->sgt = dma_buf_map_attachment(map->attach, direction);
if (IS_ERR(map->sgt)) {
dma_buf_detach(buf, map->attach);
err = PTR_ERR(map->sgt);
goto free;
}
err = __sgt_dma_count_chunks(map->sgt);
map->size = gem->size;
goto out;
}
/*
* If we don't have a mapping for this buffer yet, return an SG table
* so that host1x can do the mapping for us via the DMA API.
*/
sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
if (!sgt)
return ERR_PTR(-ENOMEM);
map->sgt = kzalloc(sizeof(*map->sgt), GFP_KERNEL);
if (!map->sgt) {
err = -ENOMEM;
goto free;
}
if (obj->pages) {
/*
* If the buffer object was allocated from the explicit IOMMU
* API code paths, construct an SG table from the pages.
*/
err = sg_alloc_table_from_pages(sgt, obj->pages, obj->num_pages,
0, obj->gem.size, GFP_KERNEL);
if (err < 0)
goto free;
} else if (obj->sgt) {
/*
* If the buffer object already has an SG table but no pages
* were allocated for it, it means the buffer was imported and
* the SG table needs to be copied to avoid overwriting any
* other potential users of the original SG table.
*/
err = sg_alloc_table_from_sg(sgt, obj->sgt->sgl,
obj->sgt->orig_nents, GFP_KERNEL);
err = sg_alloc_table_from_pages(map->sgt, obj->pages, obj->num_pages, 0, gem->size,
GFP_KERNEL);
if (err < 0)
goto free;
} else {
@@ -109,25 +114,56 @@ static struct sg_table *tegra_bo_pin(struct device *dev, struct host1x_bo *bo,
* not imported, it had to be allocated with the DMA API, so
* the DMA API helper can be used.
*/
err = dma_get_sgtable(dev, sgt, obj->vaddr, obj->iova,
obj->gem.size);
err = dma_get_sgtable(dev, map->sgt, obj->vaddr, obj->iova, gem->size);
if (err < 0)
goto free;
}
return sgt;
err = dma_map_sgtable(dev, map->sgt, direction, 0);
if (err)
goto free_sgt;
out:
/*
* If we've manually mapped the buffer object through the IOMMU, make sure to return the
* existing IOVA address of our mapping.
*/
if (!obj->mm) {
map->phys = sg_dma_address(map->sgt->sgl);
map->chunks = err;
} else {
map->phys = obj->iova;
map->chunks = 1;
}
map->size = gem->size;
return map;
free_sgt:
sg_free_table(map->sgt);
free:
kfree(sgt);
kfree(map->sgt);
kfree(map);
return ERR_PTR(err);
}
static void tegra_bo_unpin(struct device *dev, struct sg_table *sgt)
static void tegra_bo_unpin(struct host1x_bo_mapping *map)
{
if (sgt) {
sg_free_table(sgt);
kfree(sgt);
if (!map)
return;
if (map->attach) {
dma_buf_unmap_attachment(map->attach, map->sgt, map->direction);
dma_buf_detach(map->attach->dmabuf, map->attach);
} else {
dma_unmap_sgtable(map->dev, map->sgt, map->direction, 0);
sg_free_table(map->sgt);
kfree(map->sgt);
}
host1x_bo_put(map->bo);
kfree(map);
}
static void *tegra_bo_mmap(struct host1x_bo *bo)