[RFC v3 12/14] vb2: dma-sg: Let drivers decide DMA attrs of MMAP and USERPTR bufs
Sakari Ailus
sakari.ailus at linux.intel.com
Thu Apr 13 07:57:17 UTC 2017
The desirable DMA attributes are not generic for all devices using
Videobuf2 scatter-gather DMA ops. Let the drivers decide.
As a result, also the DMA-BUF exporter must provide ops for synchronising
the cache. This adds begin_cpu_access and end_cpu_access ops to
vb2_dc_dmabuf_ops.
Signed-off-by: Sakari Ailus <sakari.ailus at linux.intel.com>
---
drivers/media/v4l2-core/videobuf2-dma-sg.c | 81 +++++++++++++++++++++++-------
1 file changed, 62 insertions(+), 19 deletions(-)
diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
index 102ddb2..5662f00 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
@@ -38,6 +38,7 @@ struct vb2_dma_sg_buf {
struct frame_vector *vec;
int offset;
enum dma_data_direction dma_dir;
+ unsigned long dma_attrs;
struct sg_table sg_table;
/*
* This will point to sg_table when used with the MMAP or USERPTR
@@ -114,6 +115,7 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
buf->vaddr = NULL;
buf->dma_dir = dma_dir;
+ buf->dma_attrs = dma_attrs;
buf->offset = 0;
buf->size = size;
/* size is already page aligned */
@@ -143,7 +145,7 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
* prepare() memop is called.
*/
sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
- buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
+ buf->dma_dir, dma_attrs);
if (!sgt->nents)
goto fail_map;
@@ -181,7 +183,7 @@ static void vb2_dma_sg_put(void *buf_priv)
dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
buf->num_pages);
dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
- buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
+ buf->dma_dir, buf->dma_attrs);
if (buf->vaddr)
vm_unmap_ram(buf->vaddr, buf->num_pages);
sg_free_table(buf->dma_sgt);
@@ -198,12 +200,13 @@ static void vb2_dma_sg_prepare(void *buf_priv)
struct vb2_dma_sg_buf *buf = buf_priv;
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->orig_nents,
- buf->dma_dir);
+ /*
+ * DMABUF exporter will flush the cache for us; only USERPTR
+ * and MMAP buffers with non-coherent memory will be flushed.
+ */
+ if (buf->dma_attrs & DMA_ATTR_NON_CONSISTENT)
+ dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
+ buf->dma_dir);
}
static void vb2_dma_sg_finish(void *buf_priv)
@@ -211,11 +214,13 @@ static void vb2_dma_sg_finish(void *buf_priv)
struct vb2_dma_sg_buf *buf = buf_priv;
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->orig_nents, buf->dma_dir);
+ /*
+ * DMABUF exporter will flush the cache for us; only USERPTR
+ * and MMAP buffers with non-coherent memory will be flushed.
+ */
+ if (buf->dma_attrs & DMA_ATTR_NON_CONSISTENT)
+ dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents,
+ buf->dma_dir);
}
static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
@@ -237,6 +242,7 @@ static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
buf->vaddr = NULL;
buf->dev = dev;
buf->dma_dir = dma_dir;
+ buf->dma_attrs = dma_attrs;
buf->offset = vaddr & ~PAGE_MASK;
buf->size = size;
buf->dma_sgt = &buf->sg_table;
@@ -260,7 +266,7 @@ static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
* prepare() memop is called.
*/
sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
- buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
+ buf->dma_dir, dma_attrs);
if (!sgt->nents)
goto userptr_fail_map;
@@ -288,7 +294,7 @@ static void vb2_dma_sg_put_userptr(void *buf_priv)
dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
__func__, buf->num_pages);
dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
- DMA_ATTR_SKIP_CPU_SYNC);
+ buf->dma_attrs);
if (buf->vaddr)
vm_unmap_ram(buf->vaddr, buf->num_pages);
sg_free_table(buf->dma_sgt);
@@ -433,6 +439,7 @@ static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
{
struct vb2_dma_sg_attachment *attach = db_attach->priv;
+ struct vb2_dma_sg_buf *buf = db_attach->dmabuf->priv;
/* stealing dmabuf mutex to serialize map/unmap operations */
struct mutex *lock = &db_attach->dmabuf->lock;
struct sg_table *sgt;
@@ -448,14 +455,14 @@ static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
/* release any previous cache */
if (attach->dma_dir != DMA_NONE) {
- dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
- attach->dma_dir);
+ dma_unmap_sg_attrs(db_attach->dev, sgt->sgl, sgt->orig_nents,
+ attach->dma_dir, buf->dma_attrs);
attach->dma_dir = DMA_NONE;
}
/* mapping to the client with new direction */
- sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
- dma_dir);
+ sgt->nents = dma_map_sg_attrs(db_attach->dev, sgt->sgl, sgt->orig_nents,
+ dma_dir, buf->dma_attrs);
if (!sgt->nents) {
pr_err("failed to map scatterlist\n");
mutex_unlock(lock);
@@ -488,6 +495,40 @@ static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnu
return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL;
}
+static int vb2_dma_sg_dmabuf_ops_begin_cpu_access(
+ struct dma_buf *dbuf, enum dma_data_direction direction)
+{
+ struct vb2_dma_sg_buf *buf = dbuf->priv;
+ struct sg_table *sgt = buf->dma_sgt;
+
+ /*
+ * DMABUF exporter will flush the cache for us; only USERPTR
+ * and MMAP buffers with non-coherent memory will be flushed.
+ */
+ if (buf->dma_attrs & DMA_ATTR_NON_CONSISTENT)
+ dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents,
+ buf->dma_dir);
+
+ return 0;
+}
+
+static int vb2_dma_sg_dmabuf_ops_end_cpu_access(
+ struct dma_buf *dbuf, enum dma_data_direction direction)
+{
+ struct vb2_dma_sg_buf *buf = dbuf->priv;
+ struct sg_table *sgt = buf->dma_sgt;
+
+ /*
+ * DMABUF exporter will flush the cache for us; only USERPTR
+ * and MMAP buffers with non-coherent memory will be flushed.
+ */
+ if (buf->dma_attrs & DMA_ATTR_NON_CONSISTENT)
+ dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents,
+ buf->dma_dir);
+
+ return 0;
+}
+
static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
{
struct vb2_dma_sg_buf *buf = dbuf->priv;
@@ -508,6 +549,8 @@ static struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
.unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
.kmap = vb2_dma_sg_dmabuf_ops_kmap,
.kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap,
+ .begin_cpu_access = vb2_dma_sg_dmabuf_ops_begin_cpu_access,
+ .end_cpu_access = vb2_dma_sg_dmabuf_ops_end_cpu_access,
.vmap = vb2_dma_sg_dmabuf_ops_vmap,
.mmap = vb2_dma_sg_dmabuf_ops_mmap,
.release = vb2_dma_sg_dmabuf_ops_release,
--
2.7.4
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