From: Faith Ekstrand <[email protected]>
This enables syncing mapped GEM objects between the CPU and GPU via calls
to dma_sync_*(). It's a bit annoying as it requires walking the sg_table
so it's best if every driver doesn't hand-roll it.
When we're dealing with a dma-buf, the synchronization requests are
forwarded to the exporter through dma_buf_{begin,end}_cpu_access().
We provide a drm_gem_shmem_object_sync() for drivers that wants to
have this default implementation as their drm_gem_object_funcs::sync,
but we don't set drm_gem_shmem_funcs::sync to
drm_gem_shmem_object_sync() to avoid changing the behavior of drivers
currently relying on the default gem_shmem vtable.
v2:
- s/drm_gem_shmem_sync_mmap/drm_gem_shmem_sync/
- Change the prototype to match drm_gem_object_funcs::sync()
- Add a wrapper for drm_gem_object_funcs::sync()
Signed-off-by: Faith Ekstrand <[email protected]>
Signed-off-by: Boris Brezillon <[email protected]>
---
drivers/gpu/drm/drm_gem_shmem_helper.c | 89 ++++++++++++++++++++++++++
include/drm/drm_gem_shmem_helper.h | 11 ++++
2 files changed, 100 insertions(+)
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c
b/drivers/gpu/drm/drm_gem_shmem_helper.c
index dc94a27710e5..4094bd243cc8 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -690,6 +690,95 @@ int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem,
struct vm_area_struct
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap);
+/**
+ * drm_gem_shmem_sync - Sync CPU-mapped data to/from the device
+ * @shmem: shmem GEM object
+ * @offset: Offset into the GEM object
+ * @size: Size of the area to sync
+ * @access: Flags describing the access to sync for
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+int drm_gem_shmem_sync(struct drm_gem_shmem_object *shmem, size_t offset,
+ size_t size, enum drm_gem_object_access_flags access)
+{
+ bool for_dev = (access & DRM_GEM_OBJECT_ACCESSOR_MASK) ==
DRM_GEM_OBJECT_DEV_ACCESS;
+ u32 access_type = access & DRM_GEM_OBJECT_ACCESS_TYPE_MASK;
+ struct drm_device *dev = shmem->base.dev;
+ enum dma_data_direction dir;
+ struct sg_table *sgt;
+ struct scatterlist *sgl;
+ unsigned int count;
+
+ if (access_type == DRM_GEM_OBJECT_RW_ACCESS)
+ dir = DMA_BIDIRECTIONAL;
+ else if (access_type == DRM_GEM_OBJECT_READ_ACCESS)
+ dir = for_dev ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
+ else if (access_type == DRM_GEM_OBJECT_WRITE_ACCESS)
+ dir = for_dev ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+ else
+ return 0;
+
+ /* Don't bother if it's WC-mapped */
+ if (shmem->map_wc)
+ return 0;
+
+ if (size == 0)
+ return 0;
+
+ if (offset + size < offset || offset + size > shmem->base.size)
+ return -EINVAL;
+
+ if (drm_gem_is_imported(&shmem->base)) {
+ /* We can't do fine-grained syncs with dma_buf and there's no
+ * easy way to guarantee that CPU caches/memory won't get
+ * impacted by the buffer-wide synchronization, so let's fail
+ * instead of pretending we can cope with that.
+ */
+ if (offset != 0 || size != shmem->base.size)
+ return -EINVAL;
+
+ struct dma_buf *dma_buf = shmem->base.import_attach->dmabuf;
+
+ if (for_dev)
+ return dma_buf_end_cpu_access(dma_buf, dir);
+ else
+ return dma_buf_begin_cpu_access(dma_buf, dir);
+ }
+
+ sgt = drm_gem_shmem_get_pages_sgt(shmem);
+ if (IS_ERR(sgt))
+ return PTR_ERR(sgt);
+
+ for_each_sgtable_dma_sg(sgt, sgl, count) {
+ if (size == 0)
+ break;
+
+ dma_addr_t paddr = sg_dma_address(sgl);
+ size_t len = sg_dma_len(sgl);
+
+ if (len <= offset) {
+ offset -= len;
+ continue;
+ }
+
+ paddr += offset;
+ len -= offset;
+ len = min_t(size_t, len, size);
+ size -= len;
+ offset = 0;
+
+ if (for_dev)
+ dma_sync_single_for_device(dev->dev, paddr, len, dir);
+ else
+ dma_sync_single_for_cpu(dev->dev, paddr, len, dir);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(drm_gem_shmem_sync);
+
/**
* drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs
* @shmem: shmem GEM object
diff --git a/include/drm/drm_gem_shmem_helper.h
b/include/drm/drm_gem_shmem_helper.h
index 589f7bfe7506..6363e4ac9163 100644
--- a/include/drm/drm_gem_shmem_helper.h
+++ b/include/drm/drm_gem_shmem_helper.h
@@ -123,6 +123,8 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object
*shmem,
void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
struct iosys_map *map);
int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct
vm_area_struct *vma);
+int drm_gem_shmem_sync(struct drm_gem_shmem_object *shmem, size_t offset,
+ size_t size, enum drm_gem_object_access_flags access);
int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem);
void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem);
@@ -279,6 +281,15 @@ static inline int drm_gem_shmem_object_mmap(struct
drm_gem_object *obj, struct v
return drm_gem_shmem_mmap(shmem, vma);
}
+static inline int
+drm_gem_shmem_object_sync(struct drm_gem_object *obj, size_t offset,
+ size_t size, enum drm_gem_object_access_flags access)
+{
+ struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
+
+ return drm_gem_shmem_sync(shmem, offset, size, access);
+}
+
/*
* Driver ops
*/
--
2.51.0
