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] Acked-by: Laurent Pinchart laurent.pinchart@ideasonboard.com --- drivers/media/video/videobuf2-dma-contig.c | 120 +++++++++++++++++++++++++++- 1 file changed, 118 insertions(+), 2 deletions(-)
diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c index 494a824..a5804cf 100644 --- a/drivers/media/video/videobuf2-dma-contig.c +++ b/drivers/media/video/videobuf2-dma-contig.c @@ -10,6 +10,7 @@ * the Free Software Foundation. */
+#include <linux/dma-buf.h> #include <linux/module.h> #include <linux/scatterlist.h> #include <linux/sched.h> @@ -38,6 +39,9 @@ struct vb2_dc_buf {
/* USERPTR related */ struct vm_area_struct *vma; + + /* DMABUF related */ + struct dma_buf_attachment *db_attach; };
/*********************************************/ @@ -108,7 +112,8 @@ static void vb2_dc_prepare(void *buf_priv) struct vb2_dc_buf *buf = buf_priv; struct sg_table *sgt = buf->dma_sgt;
- if (!sgt) + /* DMABUF exporter will flush the cache for us */ + if (!sgt || buf->db_attach) return;
dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); @@ -119,7 +124,8 @@ static void vb2_dc_finish(void *buf_priv) struct vb2_dc_buf *buf = buf_priv; struct sg_table *sgt = buf->dma_sgt;
- if (!sgt) + /* DMABUF exporter will flush the cache for us */ + if (!sgt || buf->db_attach) return;
dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); @@ -377,6 +383,112 @@ 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; + + if (WARN_ON(!buf->db_attach)) { + pr_err("trying to pin a non attached buffer\n"); + return -EINVAL; + } + + if (WARN_ON(buf->dma_sgt)) { + pr_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)) { + pr_err("Error getting dmabuf scatterlist\n"); + return -EINVAL; + } + + /* checking if dmabuf is big enough to store contiguous chunk */ + contig_size = vb2_dc_get_contiguous_size(sgt); + if (contig_size < buf->size) { + pr_err("contiguous chunk is too small %lu/%lu b\n", + contig_size, buf->size); + dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); + return -EFAULT; + } + + buf->dma_addr = sg_dma_address(sgt->sgl); + buf->dma_sgt = sgt; + + return 0; +} + +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)) { + pr_err("trying to unpin a not attached buffer\n"); + return; + } + + if (WARN_ON(!sgt)) { + pr_err("dmabuf buffer is already unpinned\n"); + return; + } + + dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); + + 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 vb2 works correctly you should never detach mapped buffer */ + if (WARN_ON(buf->dma_addr)) + vb2_dc_unmap_dmabuf(buf); + + /* detach this attachment */ + dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); + kfree(buf); +} + +static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf, + unsigned long size, int write) +{ + struct vb2_dc_conf *conf = alloc_ctx; + 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 = conf->dev; + /* create attachment for the dmabuf with the user device */ + dba = dma_buf_attach(dbuf, buf->dev); + if (IS_ERR(dba)) { + pr_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 */ /*********************************************/
@@ -390,6 +502,10 @@ 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);