From: Hans Verkuil <hansv...@cisco.com>
Add support for DMABUF exporting to the vb2-vmalloc implementation.
All memory models now have support for both importing and exporting of DMABUFs.
Signed-off-by: Hans Verkuil <hansv...@cisco.com>
---
drivers/media/v4l2-core/videobuf2-vmalloc.c | 171 ++++++++++++++++++++++++++++
1 file changed, 171 insertions(+)
diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c
b/drivers/media/v4l2-core/videobuf2-vmalloc.c
index bba2460..3966b12 100644
--- a/drivers/media/v4l2-core/videobuf2-vmalloc.c
+++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c
@@ -213,6 +213,176 @@ static int vb2_vmalloc_mmap(void *buf_priv, struct
vm_area_struct *vma)
}
/*********************************************/
+/* DMABUF ops for exporters */
+/*********************************************/
+
+struct vb2_vmalloc_attachment {
+ struct sg_table sgt;
+ enum dma_data_direction dma_dir;
+};
+
+static int vb2_vmalloc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device
*dev,
+ struct dma_buf_attachment *dbuf_attach)
+{
+ struct vb2_vmalloc_attachment *attach;
+ struct vb2_vmalloc_buf *buf = dbuf->priv;
+ int num_pages = PAGE_ALIGN(buf->size) / PAGE_SIZE;
+ struct sg_table *sgt;
+ struct scatterlist *sg;
+ void *vaddr = buf->vaddr;
+ int ret;
+ int i;
+
+ attach = kzalloc(sizeof(*attach), GFP_KERNEL);
+ if (!attach)
+ return -ENOMEM;
+
+ sgt = &attach->sgt;
+ ret = sg_alloc_table(sgt, num_pages, GFP_KERNEL);
+ if (ret) {
+ kfree(attach);
+ return ret;
+ }
+ for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+ struct page *page = vmalloc_to_page(vaddr);
+
+ if (!page) {
+ sg_free_table(sgt);
+ kfree(attach);
+ return -ENOMEM;
+ }
+ sg_set_page(sg, page, PAGE_SIZE, 0);
+ vaddr += PAGE_SIZE;
+ }
+
+ attach->dma_dir = DMA_NONE;
+ dbuf_attach->priv = attach;
+ return 0;
+}
+
+static void vb2_vmalloc_dmabuf_ops_detach(struct dma_buf *dbuf,
+ struct dma_buf_attachment *db_attach)
+{
+ struct vb2_vmalloc_attachment *attach = db_attach->priv;
+ struct sg_table *sgt;
+
+ if (!attach)
+ return;
+
+ sgt = &attach->sgt;
+
+ /* release the scatterlist cache */
+ if (attach->dma_dir != DMA_NONE)
+ dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
+ attach->dma_dir);
+ sg_free_table(sgt);
+ kfree(attach);
+ db_attach->priv = NULL;
+}
+
+static struct sg_table *vb2_vmalloc_dmabuf_ops_map(
+ struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
+{
+ struct vb2_vmalloc_attachment *attach = db_attach->priv;
+ /* stealing dmabuf mutex to serialize map/unmap operations */
+ struct mutex *lock = &db_attach->dmabuf->lock;
+ struct sg_table *sgt;
+ int ret;
+
+ mutex_lock(lock);
+
+ sgt = &attach->sgt;
+ /* return previously mapped sg table */
+ if (attach->dma_dir == dma_dir) {
+ mutex_unlock(lock);
+ return sgt;
+ }
+
+ /* release any previous cache */
+ if (attach->dma_dir != DMA_NONE) {
+ dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
+ attach->dma_dir);
+ attach->dma_dir = DMA_NONE;
+ }
+
+ /* mapping to the client with new direction */
+ ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dma_dir);
+ if (ret <= 0) {
+ pr_err("failed to map scatterlist\n");
+ mutex_unlock(lock);
+ return ERR_PTR(-EIO);
+ }
+
+ attach->dma_dir = dma_dir;
+
+ mutex_unlock(lock);
+
+ return sgt;
+}
+
+static void vb2_vmalloc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
+ struct sg_table *sgt, enum dma_data_direction dma_dir)
+{
+ /* nothing to be done here */
+}
+
+static void vb2_vmalloc_dmabuf_ops_release(struct dma_buf *dbuf)
+{
+ /* drop reference obtained in vb2_vmalloc_get_dmabuf */
+ vb2_vmalloc_put(dbuf->priv);
+}
+
+static void *vb2_vmalloc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long
pgnum)
+{
+ struct vb2_vmalloc_buf *buf = dbuf->priv;
+
+ return buf->vaddr + pgnum * PAGE_SIZE;
+}
+
+static void *vb2_vmalloc_dmabuf_ops_vmap(struct dma_buf *dbuf)
+{
+ struct vb2_vmalloc_buf *buf = dbuf->priv;
+
+ return buf->vaddr;
+}
+
+static int vb2_vmalloc_dmabuf_ops_mmap(struct dma_buf *dbuf,
+ struct vm_area_struct *vma)
+{
+ return vb2_vmalloc_mmap(dbuf->priv, vma);
+}
+
+static struct dma_buf_ops vb2_vmalloc_dmabuf_ops = {
+ .attach = vb2_vmalloc_dmabuf_ops_attach,
+ .detach = vb2_vmalloc_dmabuf_ops_detach,
+ .map_dma_buf = vb2_vmalloc_dmabuf_ops_map,
+ .unmap_dma_buf = vb2_vmalloc_dmabuf_ops_unmap,
+ .kmap = vb2_vmalloc_dmabuf_ops_kmap,
+ .kmap_atomic = vb2_vmalloc_dmabuf_ops_kmap,
+ .vmap = vb2_vmalloc_dmabuf_ops_vmap,
+ .mmap = vb2_vmalloc_dmabuf_ops_mmap,
+ .release = vb2_vmalloc_dmabuf_ops_release,
+};
+
+static struct dma_buf *vb2_vmalloc_get_dmabuf(void *buf_priv, unsigned long
flags)
+{
+ struct vb2_vmalloc_buf *buf = buf_priv;
+ struct dma_buf *dbuf;
+
+ if (WARN_ON(!buf->vaddr))
+ return NULL;
+
+ dbuf = dma_buf_export(buf, &vb2_vmalloc_dmabuf_ops, buf->size, flags,
NULL);
+ if (IS_ERR(dbuf))
+ return NULL;
+
+ /* dmabuf keeps reference to vb2 buffer */
+ atomic_inc(&buf->refcount);
+
+ return dbuf;
+}
+
+/*********************************************/
/* callbacks for DMABUF buffers */
/*********************************************/
@@ -268,6 +438,7 @@ const struct vb2_mem_ops vb2_vmalloc_memops = {
.put = vb2_vmalloc_put,
.get_userptr = vb2_vmalloc_get_userptr,
.put_userptr = vb2_vmalloc_put_userptr,
+ .get_dmabuf = vb2_vmalloc_get_dmabuf,
.map_dmabuf = vb2_vmalloc_map_dmabuf,
.unmap_dmabuf = vb2_vmalloc_unmap_dmabuf,
.attach_dmabuf = vb2_vmalloc_attach_dmabuf,
--
2.1.1
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