[media] vb2-dma-sg: add allocation context to dma-sg

Require that dma-sg also uses an allocation context. This is in preparation
for adding prepare/finish memops to sync the memory between DMA and CPU.

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, 32 insertions, 0 deletions

diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
index 2529b831725b..2bf13dc4df34 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
@@ -30,7 +30,12 @@ module_param(debug, int, 0644);
                         printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg);  \
         } while (0)
 
+struct vb2_dma_sg_conf {
+        struct device           *dev;
+};
+
 struct vb2_dma_sg_buf {
+        struct device                   *dev;
         void                            *vaddr;
         struct page                     **pages;
         int                             offset;
@@ -89,10 +94,13 @@ static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
 static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size,
                               enum dma_data_direction dma_dir, gfp_t gfp_flags)
 {
+        struct vb2_dma_sg_conf *conf = alloc_ctx;
         struct vb2_dma_sg_buf *buf;
         int ret;
         int num_pages;
 
+        if (WARN_ON(alloc_ctx == NULL))
+                return NULL;
         buf = kzalloc(sizeof *buf, GFP_KERNEL);
         if (!buf)
                 return NULL;
@@ -118,6 +126,8 @@ static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size,
         if (ret)
                 goto fail_table_alloc;
 
+        /* Prevent the device from being released while the buffer is used */
+        buf->dev = get_device(conf->dev);
         buf->handler.refcount = &buf->refcount;
         buf->handler.put = vb2_dma_sg_put;
         buf->handler.arg = buf;
@@ -153,6 +163,7 @@ static void vb2_dma_sg_put(void *buf_priv)
                 while (--i >= 0)
                         __free_page(buf->pages[i]);
                 kfree(buf->pages);
+                put_device(buf->dev);
                 kfree(buf);
         }
 }
@@ -356,6 +367,27 @@ const struct vb2_mem_ops vb2_dma_sg_memops = {
 };
 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
 
+void *vb2_dma_sg_init_ctx(struct device *dev)
+{
+        struct vb2_dma_sg_conf *conf;
+
+        conf = kzalloc(sizeof(*conf), GFP_KERNEL);
+        if (!conf)
+                return ERR_PTR(-ENOMEM);
+
+        conf->dev = dev;
+
+        return conf;
+}
+EXPORT_SYMBOL_GPL(vb2_dma_sg_init_ctx);
+
+void vb2_dma_sg_cleanup_ctx(void *alloc_ctx)
+{
+        if (!IS_ERR_OR_NULL(alloc_ctx))
+                kfree(alloc_ctx);
+}
+EXPORT_SYMBOL_GPL(vb2_dma_sg_cleanup_ctx);
+
 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
 MODULE_AUTHOR("Andrzej Pietrasiewicz");
 MODULE_LICENSE("GPL");