From 041c7b6ac74ee7a4375faf80e2864fc2bce78edc Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Tue, 18 Nov 2014 09:51:04 -0300 Subject: [PATCH] [media] vb2-dma-sg: add support for dmabuf exports Add DMABUF export support to vb2-dma-sg. Signed-off-by: Hans Verkuil Acked-by: Pawel Osciak Signed-off-by: Mauro Carvalho Chehab --- drivers/media/v4l2-core/videobuf2-dma-sg.c | 170 +++++++++++++++++++++++++++++ 1 file changed, 170 insertions(+) diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c index 81e88a0..0566e94 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-sg.c +++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c @@ -408,6 +408,175 @@ static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) } /*********************************************/ +/* DMABUF ops for exporters */ +/*********************************************/ + +struct vb2_dma_sg_attachment { + struct sg_table sgt; + enum dma_data_direction dma_dir; +}; + +static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev, + struct dma_buf_attachment *dbuf_attach) +{ + struct vb2_dma_sg_attachment *attach; + unsigned int i; + struct scatterlist *rd, *wr; + struct sg_table *sgt; + struct vb2_dma_sg_buf *buf = dbuf->priv; + int ret; + + attach = kzalloc(sizeof(*attach), GFP_KERNEL); + if (!attach) + return -ENOMEM; + + sgt = &attach->sgt; + /* Copy the buf->base_sgt scatter list to the attachment, as we can't + * map the same scatter list to multiple attachments at the same time. + */ + ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL); + if (ret) { + kfree(attach); + return -ENOMEM; + } + + rd = buf->dma_sgt->sgl; + wr = sgt->sgl; + for (i = 0; i < sgt->orig_nents; ++i) { + sg_set_page(wr, sg_page(rd), rd->length, rd->offset); + rd = sg_next(rd); + wr = sg_next(wr); + } + + attach->dma_dir = DMA_NONE; + dbuf_attach->priv = attach; + + return 0; +} + +static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf, + struct dma_buf_attachment *db_attach) +{ + struct vb2_dma_sg_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_dma_sg_dmabuf_ops_map( + struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) +{ + struct vb2_dma_sg_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_dma_sg_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_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf) +{ + /* drop reference obtained in vb2_dma_sg_get_dmabuf */ + vb2_dma_sg_put(dbuf->priv); +} + +static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum) +{ + struct vb2_dma_sg_buf *buf = dbuf->priv; + + return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL; +} + +static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf) +{ + struct vb2_dma_sg_buf *buf = dbuf->priv; + + return vb2_dma_sg_vaddr(buf); +} + +static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf, + struct vm_area_struct *vma) +{ + return vb2_dma_sg_mmap(dbuf->priv, vma); +} + +static struct dma_buf_ops vb2_dma_sg_dmabuf_ops = { + .attach = vb2_dma_sg_dmabuf_ops_attach, + .detach = vb2_dma_sg_dmabuf_ops_detach, + .map_dma_buf = vb2_dma_sg_dmabuf_ops_map, + .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap, + .kmap = vb2_dma_sg_dmabuf_ops_kmap, + .kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap, + .vmap = vb2_dma_sg_dmabuf_ops_vmap, + .mmap = vb2_dma_sg_dmabuf_ops_mmap, + .release = vb2_dma_sg_dmabuf_ops_release, +}; + +static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags) +{ + struct vb2_dma_sg_buf *buf = buf_priv; + struct dma_buf *dbuf; + + if (WARN_ON(!buf->dma_sgt)) + return NULL; + + dbuf = dma_buf_export(buf, &vb2_dma_sg_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 */ /*********************************************/ @@ -523,6 +692,7 @@ const struct vb2_mem_ops vb2_dma_sg_memops = { .vaddr = vb2_dma_sg_vaddr, .mmap = vb2_dma_sg_mmap, .num_users = vb2_dma_sg_num_users, + .get_dmabuf = vb2_dma_sg_get_dmabuf, .map_dmabuf = vb2_dma_sg_map_dmabuf, .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf, .attach_dmabuf = vb2_dma_sg_attach_dmabuf, -- 2.7.4