Hi Tomasz,
On Tuesday 13 March 2012 11:17:01 Tomasz Stanislawski wrote:
From: Sumit Semwal sumit.semwal@ti.com
This patch makes changes for adding dma-contig as a dma_buf user. It provides function implementations for the {attach, detach, map, unmap}_dmabuf() mem_ops of DMABUF memory type.
Signed-off-by: Sumit Semwal sumit.semwal@ti.com Signed-off-by: Sumit Semwal sumit.semwal@linaro.org [author of the original patch] Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com [integration with refactored dma-contig allocator]
drivers/media/video/videobuf2-dma-contig.c | 116 ++++++++++++++++++++++++++++ 1 files changed, 116 insertions(+), 0 deletions(-)
diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c index c1dc043..746dd5f 100644 --- a/drivers/media/video/videobuf2-dma-contig.c +++ b/drivers/media/video/videobuf2-dma-contig.c @@ -35,6 +35,9 @@ struct vb2_dc_buf {
/* USERPTR related */ struct vm_area_struct *vma;
- /* DMABUF related */
- struct dma_buf_attachment *db_attach;
};
/*********************************************/ @@ -485,6 +488,115 @@ fail_buf: }
/*********************************************/ +/* callbacks for DMABUF buffers */ +/*********************************************/
+static int vb2_dc_map_dmabuf(void *mem_priv) +{
- struct vb2_dc_buf *buf = mem_priv;
- struct sg_table *sgt;
- unsigned long contig_size;
- int ret = 0;
- if (WARN_ON(!buf->db_attach)) {
printk(KERN_ERR "trying to pin a non attached buffer\n");return -EINVAL;- }
- if (WARN_ON(buf->dma_sgt)) {
printk(KERN_ERR "dmabuf buffer is already pinned\n");return 0;- }
- /* get the associated scatterlist for this buffer */
- sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
- if (IS_ERR_OR_NULL(sgt)) {
printk(KERN_ERR "Error getting dmabuf scatterlist\n");return -EINVAL;- }
I've checked why dma_map_sg() was missing from here, and then remembered that the exporter is still responsible for mapping the buffer to the importer's device address space :-) I'll raise that topic separately.
- /* checking if dmabuf is big enough to store contiguous chunk */
- contig_size = vb2_dc_get_contiguous_size(sgt);
- if (contig_size < buf->size) {
printk(KERN_ERR "contiguous chunk of dmabuf is too small\n");ret = -EFAULT;goto fail_map;- }
- buf->dma_addr = sg_dma_address(sgt->sgl);
- buf->dma_sgt = sgt;
- return 0;
+fail_map:
- dma_buf_unmap_attachment(buf->db_attach, sgt);
- return ret;
+}
+static void vb2_dc_unmap_dmabuf(void *mem_priv) +{
- struct vb2_dc_buf *buf = mem_priv;
- struct sg_table *sgt = buf->dma_sgt;
- if (WARN_ON(!buf->db_attach)) {
printk(KERN_ERR "trying to unpin a not attached buffer\n");return;- }
- if (WARN_ON(!sgt)) {
printk(KERN_ERR "dmabuf buffer is already unpinned\n");return;- }
- dma_buf_unmap_attachment(buf->db_attach, sgt);
- buf->dma_addr = 0;
- buf->dma_sgt = NULL;
+}
+static void vb2_dc_detach_dmabuf(void *mem_priv) +{
- struct vb2_dc_buf *buf = mem_priv;
- if (buf->dma_addr)
vb2_dc_unmap_dmabuf(buf);
Can detach() be called with the buffer still mapped() ? Wouldn't that be a bug in the caller ?
- /* detach this attachment */
- dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
- kfree(buf);
+}
There's nothing allocator-specific in the attach/detach operations. Shouldn't they be moved to the vb2 core ?
+static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
- unsigned long size, int write)
+{
- struct vb2_dc_buf *buf;
- struct dma_buf_attachment *dba;
- if (dbuf->size < size)
return ERR_PTR(-EFAULT);- buf = kzalloc(sizeof *buf, GFP_KERNEL);
- if (!buf)
return ERR_PTR(-ENOMEM);- buf->dev = alloc_ctx;
- /* create attachment for the dmabuf with the user device */
- dba = dma_buf_attach(dbuf, buf->dev);
- if (IS_ERR(dba)) {
printk(KERN_ERR "failed to attach dmabuf\n");kfree(buf);return dba;- }
- buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
- buf->size = size;
- buf->db_attach = dba;
- return buf;
+}
+/*********************************************/ /* DMA CONTIG exported functions */ /*********************************************/
@@ -498,6 +610,10 @@ const struct vb2_mem_ops vb2_dma_contig_memops = { .put_userptr = vb2_dc_put_userptr, .prepare = vb2_dc_prepare, .finish = vb2_dc_finish,
- .map_dmabuf = vb2_dc_map_dmabuf,
- .unmap_dmabuf = vb2_dc_unmap_dmabuf,
- .attach_dmabuf = vb2_dc_attach_dmabuf,
- .detach_dmabuf = vb2_dc_detach_dmabuf, .num_users = vb2_dc_num_users,
}; EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);