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drm/tegra: gem: Don't attach dma-bufs when not needed

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The dma-buf import code currently attaches and maps all imported
dma-bufs to the drm device to get their sgt for mapping to the
directly managed IOMMU domain.

In many cases, like for newer chips (Tegra186+), the directly
managed IOMMU domain is, however, not used. Mapping to the drm
device can also cause issues e.g. with swiotlb since it is not
a real device.

To improve the situation, only attach and map imported dma-bufs
when required.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Change-Id: If73cc4e9419a2eebf67269eadb34050986f73077
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/3090413
Reviewed-by: Santosh BS <santoshb@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>
This commit is contained in:
Mikko Perttunen
2024-03-06 09:27:19 +02:00
committed by mobile promotions
parent a050b8203b
commit c2d209f066
2 changed files with 58 additions and 31 deletions
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68
drivers/gpu/drm/tegra/gem.c
View File

@@ -77,8 +77,8 @@ static struct host1x_bo_mapping *tegra_bo_pin(struct device *dev, struct host1x_
/*
* Imported buffers need special treatment to satisfy the semantics of DMA-BUF.
*/
if (gem->import_attach) {
struct dma_buf *buf = gem->import_attach->dmabuf;
if (obj->dma_buf) {
struct dma_buf *buf = obj->dma_buf;
map->attach = dma_buf_attach(buf, dev);
if (IS_ERR(map->attach)) {
@@ -186,8 +186,8 @@ static void *tegra_bo_mmap(struct host1x_bo *bo)
if (obj->vaddr) {
return obj->vaddr;
} else if (obj->gem.import_attach) {
ret = dma_buf_vmap(obj->gem.import_attach->dmabuf, &map);
} else if (obj->dma_buf) {
ret = dma_buf_vmap(obj->dma_buf, &map);
return ret ? NULL : map.vaddr;
} else {
return vmap(obj->pages, obj->num_pages, VM_MAP,
@@ -206,8 +206,8 @@ static void tegra_bo_munmap(struct host1x_bo *bo, void *addr)
if (obj->vaddr)
return;
else if (obj->gem.import_attach)
dma_buf_vunmap(obj->gem.import_attach->dmabuf, &map);
else if (obj->dma_buf)
dma_buf_vunmap(obj->dma_buf, &map);
else
vunmap(addr);
}
@@ -463,27 +463,32 @@ static struct tegra_bo *tegra_bo_import(struct drm_device *drm,
if (IS_ERR(bo))
return bo;
attach = dma_buf_attach(buf, drm->dev);
if (IS_ERR(attach)) {
err = PTR_ERR(attach);
goto free;
}
get_dma_buf(buf);
bo->sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
if (IS_ERR(bo->sgt)) {
err = PTR_ERR(bo->sgt);
goto detach;
}
/*
* If we need to use IOMMU API to map the dma-buf into the internally managed
* domain, map it first to the DRM device to get an sgt.
*/
if (tegra->domain) {
attach = dma_buf_attach(buf, drm->dev);
if (IS_ERR(attach)) {
err = PTR_ERR(attach);
goto free;
}
bo->sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
if (IS_ERR(bo->sgt)) {
err = PTR_ERR(bo->sgt);
goto detach;
}
err = tegra_bo_iommu_map(tegra, bo);
if (err < 0)
goto detach;
bo->gem.import_attach = attach;
}
bo->gem.import_attach = attach;
get_dma_buf(buf);
bo->dma_buf = buf;
return bo;
@@ -514,20 +519,21 @@ void tegra_bo_free_object(struct drm_gem_object *gem)
dev_name(mapping->dev));
}
if (tegra->domain)
if (tegra->domain) {
tegra_bo_iommu_unmap(tegra, bo);
if (gem->import_attach) {
struct dma_buf *dmabuf = gem->import_attach->dmabuf;
dma_buf_unmap_attachment(gem->import_attach, bo->sgt,
DMA_TO_DEVICE);
dma_buf_detach(dmabuf, gem->import_attach);
dma_buf_put(dmabuf);
} else {
tegra_bo_free(gem->dev, bo);
if (gem->import_attach) {
dma_buf_unmap_attachment(gem->import_attach, bo->sgt,
DMA_TO_DEVICE);
dma_buf_detach(gem->import_attach->dmabuf, gem->import_attach);
}
}
tegra_bo_free(gem->dev, bo);
if (bo->dma_buf)
dma_buf_put(bo->dma_buf);
drm_gem_object_release(gem);
kfree(bo);
}