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 --- drivers/media/video/videobuf2-dma-contig.c | 125 ++++++++++++++++++++++++++++ 1 files changed, 125 insertions(+), 0 deletions(-)
diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c index f17ad98..e671371 100644 --- a/drivers/media/video/videobuf2-dma-contig.c +++ b/drivers/media/video/videobuf2-dma-contig.c @@ -13,6 +13,8 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/dma-mapping.h> +#include <linux/scatterlist.h> +#include <linux/dma-buf.h>
#include <media/videobuf2-core.h> #include <media/videobuf2-memops.h> @@ -27,6 +29,7 @@ struct vb2_dc_buf { dma_addr_t dma_addr; unsigned long size; struct vm_area_struct *vma; + struct dma_buf_attachment *db_attach; atomic_t refcount; struct vb2_vmarea_handler handler; }; @@ -37,6 +40,7 @@ static void *vb2_dma_contig_alloc(void *alloc_ctx, unsigned long size) { struct vb2_dc_conf *conf = alloc_ctx; struct vb2_dc_buf *buf; + /* TODO: add db_attach processing while adding DMABUF as exporter */
buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) @@ -106,6 +110,8 @@ static int vb2_dma_contig_mmap(void *buf_priv, struct vm_area_struct *vma) return -EINVAL; }
+ WARN_ON(buf->db_attach); + return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size, &vb2_common_vm_ops, &buf->handler); } @@ -148,6 +154,121 @@ static void vb2_dma_contig_put_userptr(void *mem_priv) kfree(buf); }
+static int vb2_dma_contig_map_dmabuf(void *mem_priv, + enum dma_data_direction direction) +{ + struct vb2_dc_buf *buf = mem_priv; + struct dma_buf *dmabuf; + struct sg_table *sg; + + if (!buf || !buf->db_attach) { + printk(KERN_ERR "No dma buffer to pin\n"); + return -EINVAL; + } + + WARN_ON(buf->dma_addr); + + if (direction == DMA_NONE) { + printk(KERN_ERR "Incorrect DMA direction\n"); + return -EINVAL; + } + + dmabuf = buf->db_attach->dmabuf; + + /* get the associated scatterlist for this buffer */ + sg = dma_buf_map_attachment(buf->db_attach, direction); + + if (!sg) { + printk(KERN_ERR "Error getting dmabuf scatterlist\n"); + return -EINVAL; + } + + /* + * convert sglist to paddr: + * Assumption: for dma-contig, dmabuf would map to single entry + * Will return an error if it has more than one. + */ + if (sg->nents > 1) { + printk(KERN_ERR + "dmabuf scatterlist has more than 1 entry\n"); + return -EINVAL; + } + + buf->dma_addr = sg_dma_address(sg->sgl); + /* TODO: check the buffer size as per S_FMT */ + buf->size = sg_dma_len(sg->sgl); + + /* save this scatterlist in dmabuf for put_scatterlist */ + dmabuf->priv = sg; + + return 0; +} + +static void vb2_dma_contig_unmap_dmabuf(void *mem_priv) +{ + struct vb2_dc_buf *buf = mem_priv; + struct dma_buf *dmabuf; + struct sg_table *sg; + + if (!buf || !buf->db_attach) + return; + + WARN_ON(!buf->dma_addr); + + dmabuf = buf->db_attach->dmabuf; + sg = dmabuf->priv; + + /* Put the sg for this buffer */ + dma_buf_unmap_attachment(buf->db_attach, sg); + + buf->dma_addr = 0; + buf->size = 0; +} + +static void *vb2_dma_contig_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf) +{ + struct vb2_dc_conf *conf = alloc_ctx; + struct vb2_dc_buf *buf; + struct dma_buf_attachment *dba; + + buf = kzalloc(sizeof *buf, GFP_KERNEL); + if (!buf) + return ERR_PTR(-ENOMEM); + + /* create attachment for the dmabuf with the user device */ + dba = dma_buf_attach(dbuf, conf->dev); + if (IS_ERR(dba)) { + printk(KERN_ERR "failed to attach dmabuf\n"); + kfree(buf); + return dba; + } + + buf->conf = conf; + buf->size = dba->dmabuf->size; + buf->db_attach = dba; + buf->dma_addr = 0; /* dma_addr is available only after map */ + + return buf; +} + +static void vb2_dma_contig_detach_dmabuf(void *mem_priv) +{ + struct vb2_dc_buf *buf = mem_priv; + + if (!buf) + return; + + if (buf->dma_addr) { + vb2_dma_contig_unmap_dmabuf(buf); + } + + /* detach this attachment */ + dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); + buf->db_attach = NULL; + + kfree(buf); +} + const struct vb2_mem_ops vb2_dma_contig_memops = { .alloc = vb2_dma_contig_alloc, .put = vb2_dma_contig_put, @@ -156,6 +277,10 @@ const struct vb2_mem_ops vb2_dma_contig_memops = { .mmap = vb2_dma_contig_mmap, .get_userptr = vb2_dma_contig_get_userptr, .put_userptr = vb2_dma_contig_put_userptr, + .map_dmabuf = vb2_dma_contig_map_dmabuf, + .unmap_dmabuf = vb2_dma_contig_unmap_dmabuf, + .attach_dmabuf = vb2_dma_contig_attach_dmabuf, + .detach_dmabuf = vb2_dma_contig_detach_dmabuf, .num_users = vb2_dma_contig_num_users, }; EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);