[media] vb2-dma-sg: add dmabuf import support

Add support for importing dmabuf to videobuf2-dma-sg.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Pawel Osciak <pawel@osciak.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

1 files changed, 137 insertions, 14 deletions

diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
index 346e39b2aae8..81e88a067882 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
@@ -41,11 +41,19 @@ struct vb2_dma_sg_buf {
         int                             offset;
         enum dma_data_direction         dma_dir;
         struct sg_table                 sg_table;
+        /*
+         * This will point to sg_table when used with the MMAP or USERPTR
+         * memory model, and to the dma_buf sglist when used with the
+         * DMABUF memory model.
+         */
+        struct sg_table                 *dma_sgt;
         size_t                          size;
         unsigned int                    num_pages;
         atomic_t                        refcount;
         struct vb2_vmarea_handler       handler;
         struct vm_area_struct           *vma;
+
+        struct dma_buf_attachment       *db_attach;
 };
 
 static void vb2_dma_sg_put(void *buf_priv);
@@ -112,6 +120,7 @@ static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size,
         buf->size = size;
         /* size is already page aligned */
         buf->num_pages = size >> PAGE_SHIFT;
+        buf->dma_sgt = &buf->sg_table;
 
         buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
                              GFP_KERNEL);
@@ -122,7 +131,7 @@ static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size,
         if (ret)
                 goto fail_pages_alloc;
 
-        ret = sg_alloc_table_from_pages(&buf->sg_table, buf->pages,
+        ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
                         buf->num_pages, 0, size, GFP_KERNEL);
         if (ret)
                 goto fail_table_alloc;
@@ -147,7 +156,7 @@ static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size,
 
 fail_map:
         put_device(buf->dev);
-        sg_free_table(sgt);
+        sg_free_table(buf->dma_sgt);
 fail_table_alloc:
         num_pages = buf->num_pages;
         while (num_pages--)
@@ -171,7 +180,7 @@ static void vb2_dma_sg_put(void *buf_priv)
                 dma_unmap_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
                 if (buf->vaddr)
                         vm_unmap_ram(buf->vaddr, buf->num_pages);
-                sg_free_table(&buf->sg_table);
+                sg_free_table(buf->dma_sgt);
                 while (--i >= 0)
                         __free_page(buf->pages[i]);
                 kfree(buf->pages);
@@ -183,7 +192,11 @@ static void vb2_dma_sg_put(void *buf_priv)
 static void vb2_dma_sg_prepare(void *buf_priv)
 {
         struct vb2_dma_sg_buf *buf = buf_priv;
-        struct sg_table *sgt = &buf->sg_table;
+        struct sg_table *sgt = buf->dma_sgt;
+
+        /* DMABUF exporter will flush the cache for us */
+        if (buf->db_attach)
+                return;
 
         dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 }
@@ -191,7 +204,11 @@ static void vb2_dma_sg_prepare(void *buf_priv)
 static void vb2_dma_sg_finish(void *buf_priv)
 {
         struct vb2_dma_sg_buf *buf = buf_priv;
-        struct sg_table *sgt = &buf->sg_table;
+        struct sg_table *sgt = buf->dma_sgt;
+
+        /* DMABUF exporter will flush the cache for us */
+        if (buf->db_attach)
+                return;
 
         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 }
@@ -221,6 +238,7 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
         buf->dma_dir = dma_dir;
         buf->offset = vaddr & ~PAGE_MASK;
         buf->size = size;
+        buf->dma_sgt = &buf->sg_table;
 
         first = (vaddr           & PAGE_MASK) >> PAGE_SHIFT;
         last  = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
@@ -273,7 +291,7 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
         if (num_pages_from_user != buf->num_pages)
                 goto userptr_fail_get_user_pages;
 
-        if (sg_alloc_table_from_pages(&buf->sg_table, buf->pages,
+        if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
                         buf->num_pages, buf->offset, size, 0))
                 goto userptr_fail_alloc_table_from_pages;
 
@@ -315,7 +333,7 @@ static void vb2_dma_sg_put_userptr(void *buf_priv)
         dma_unmap_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
         if (buf->vaddr)
                 vm_unmap_ram(buf->vaddr, buf->num_pages);
-        sg_free_table(&buf->sg_table);
+        sg_free_table(buf->dma_sgt);
         while (--i >= 0) {
                 if (buf->dma_dir == DMA_FROM_DEVICE)
                         set_page_dirty_lock(buf->pages[i]);
@@ -333,14 +351,16 @@ static void *vb2_dma_sg_vaddr(void *buf_priv)
 
         BUG_ON(!buf);
 
-        if (!buf->vaddr)
-                buf->vaddr = vm_map_ram(buf->pages,
-                                        buf->num_pages,
-                                        -1,
-                                        PAGE_KERNEL);
+        if (!buf->vaddr) {
+                if (buf->db_attach)
+                        buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
+                else
+                        buf->vaddr = vm_map_ram(buf->pages,
+                                        buf->num_pages, -1, PAGE_KERNEL);
+        }
 
         /* add offset in case userptr is not page-aligned */
-        return buf->vaddr + buf->offset;
+        return buf->vaddr ? buf->vaddr + buf->offset : NULL;
 }
 
 static unsigned int vb2_dma_sg_num_users(void *buf_priv)
@@ -387,11 +407,110 @@ static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
         return 0;
 }
 
+/*********************************************/
+/*       callbacks for DMABUF buffers        */
+/*********************************************/
+
+static int vb2_dma_sg_map_dmabuf(void *mem_priv)
+{
+        struct vb2_dma_sg_buf *buf = mem_priv;
+        struct sg_table *sgt;
+
+        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(sgt)) {
+                pr_err("Error getting dmabuf scatterlist\n");
+                return -EINVAL;
+        }
+
+        buf->dma_sgt = sgt;
+        buf->vaddr = NULL;
+
+        return 0;
+}
+
+static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
+{
+        struct vb2_dma_sg_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;
+        }
+
+        if (buf->vaddr) {
+                dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
+                buf->vaddr = NULL;
+        }
+        dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
+
+        buf->dma_sgt = NULL;
+}
+
+static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
+{
+        struct vb2_dma_sg_buf *buf = mem_priv;
+
+        /* if vb2 works correctly you should never detach mapped buffer */
+        if (WARN_ON(buf->dma_sgt))
+                vb2_dma_sg_unmap_dmabuf(buf);
+
+        /* detach this attachment */
+        dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
+        kfree(buf);
+}
+
+static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
+        unsigned long size, enum dma_data_direction dma_dir)
+{
+        struct vb2_dma_sg_conf *conf = alloc_ctx;
+        struct vb2_dma_sg_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 = dma_dir;
+        buf->size = size;
+        buf->db_attach = dba;
+
+        return buf;
+}
+
 static void *vb2_dma_sg_cookie(void *buf_priv)
 {
         struct vb2_dma_sg_buf *buf = buf_priv;
 
-        return &buf->sg_table;
+        return buf->dma_sgt;
 }
 
 const struct vb2_mem_ops vb2_dma_sg_memops = {
@@ -404,6 +523,10 @@ 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,
+        .map_dmabuf     = vb2_dma_sg_map_dmabuf,
+        .unmap_dmabuf   = vb2_dma_sg_unmap_dmabuf,
+        .attach_dmabuf  = vb2_dma_sg_attach_dmabuf,
+        .detach_dmabuf  = vb2_dma_sg_detach_dmabuf,
         .cookie         = vb2_dma_sg_cookie,
 };
 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);