[PATCHv6 0/8] videobuf2: support new noncontiguous DMA API

[PATCHv6 0/8] videobuf2: support new noncontiguous DMA API

[Sergey Senozhatsky]

Hello,

        The series adds support for noncontiguous DMA API and
V4L2_MEMORY_FLAG_NON_COHERENT UAPI.

v5:

https://lore.kernel.org/lkml/20210823122235.116189-1-senozhatsky@chromium.org/

-- addressed feedback (Tomasz)
-- reworked prepare/finish functions (Tomasz)

Sergey Senozhatsky (8):
  videobuf2: rework vb2_mem_ops API
  videobuf2: inverse buffer cache_hints flags
  videobuf2: split buffer cache_hints initialisation
  videobuf2: move cache_hints handling to allocators
  videobuf2: add V4L2_MEMORY_FLAG_NON_COHERENT flag
  videobuf2: add queue memory coherency parameter
  videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag
  videobuf2: handle non-contiguous DMA allocations

 .../userspace-api/media/v4l/buffer.rst        |  40 +++-
 .../media/v4l/vidioc-create-bufs.rst          |   7 +-
 .../media/v4l/vidioc-reqbufs.rst              |  16 +-
 .../media/common/videobuf2/videobuf2-core.c   | 126 +++++++----
 .../common/videobuf2/videobuf2-dma-contig.c   | 195 ++++++++++++++----
 .../media/common/videobuf2/videobuf2-dma-sg.c |  39 ++--
 .../media/common/videobuf2/videobuf2-v4l2.c   |  59 +++---
 .../common/videobuf2/videobuf2-vmalloc.c      |  30 +--
 drivers/media/dvb-core/dvb_vb2.c              |   2 +-
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c |   9 +-
 drivers/media/v4l2-core/v4l2-ioctl.c          |   4 +-
 include/media/videobuf2-core.h                |  59 +++---
 include/uapi/linux/videodev2.h                |  11 +-
 13 files changed, 411 insertions(+), 186 deletions(-)

-- 
2.33.0.153.gba50c8fa24-goog

[PATCHv6 1/8] videobuf2: rework vb2_mem_ops API

[Sergey Senozhatsky]

With the new DMA API we need an extension of the videobuf2 API.
Previously, videobuf2 core would set the non-coherent DMA bit
in the vb2_queue dma_attr field (if user-space would pass a
corresponding memory hint); the vb2 core then would pass the
vb2_queue dma_attrs to the vb2 allocators. The vb2 allocator
would use the queue's dma_attr and the DMA API would allocate
either coherent or non-coherent memory.

But we cannot do this anymore, since there is no corresponding DMA
attr flag and, hence, there is no way for the allocator to become
aware of what type of allocation user-space has requested. So we
need to pass more context from videobuf2 core to the allocators.

Fix this by changing the call_ptr_memop() macro to pass the
vb2 pointer to the corresponding op callbacks.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 .../media/common/videobuf2/videobuf2-core.c   | 42 +++++++++++--------
 .../common/videobuf2/videobuf2-dma-contig.c   | 36 +++++++++-------
 .../media/common/videobuf2/videobuf2-dma-sg.c | 33 ++++++++-------
 .../common/videobuf2/videobuf2-vmalloc.c      | 30 ++++++-------
 include/media/videobuf2-core.h                | 37 ++++++++--------
 5 files changed, 98 insertions(+), 80 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 38ce7c274727..c4ff356da600 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -68,13 +68,13 @@ module_param(debug, int, 0644);
 	err;								\
 })
 
-#define call_ptr_memop(vb, op, args...)					\
+#define call_ptr_memop(op, vb, args...)					\
 ({									\
 	struct vb2_queue *_q = (vb)->vb2_queue;				\
 	void *ptr;							\
 									\
 	log_memop(vb, op);						\
-	ptr = _q->mem_ops->op ? _q->mem_ops->op(args) : NULL;		\
+	ptr = _q->mem_ops->op ? _q->mem_ops->op(vb, args) : NULL;	\
 	if (!IS_ERR_OR_NULL(ptr))					\
 		(vb)->cnt_mem_ ## op++;					\
 	ptr;								\
@@ -144,9 +144,9 @@ module_param(debug, int, 0644);
 	((vb)->vb2_queue->mem_ops->op ?					\
 		(vb)->vb2_queue->mem_ops->op(args) : 0)
 
-#define call_ptr_memop(vb, op, args...)					\
+#define call_ptr_memop(op, vb, args...)					\
 	((vb)->vb2_queue->mem_ops->op ?					\
-		(vb)->vb2_queue->mem_ops->op(args) : NULL)
+		(vb)->vb2_queue->mem_ops->op(vb, args) : NULL)
 
 #define call_void_memop(vb, op, args...)				\
 	do {								\
@@ -230,9 +230,10 @@ static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
 		if (size < vb->planes[plane].length)
 			goto free;
 
-		mem_priv = call_ptr_memop(vb, alloc,
-				q->alloc_devs[plane] ? : q->dev,
-				q->dma_attrs, size, q->dma_dir, q->gfp_flags);
+		mem_priv = call_ptr_memop(alloc,
+					  vb,
+					  q->alloc_devs[plane] ? : q->dev,
+					  size);
 		if (IS_ERR_OR_NULL(mem_priv)) {
 			if (mem_priv)
 				ret = PTR_ERR(mem_priv);
@@ -975,7 +976,7 @@ void *vb2_plane_vaddr(struct vb2_buffer *vb, unsigned int plane_no)
 	if (plane_no >= vb->num_planes || !vb->planes[plane_no].mem_priv)
 		return NULL;
 
-	return call_ptr_memop(vb, vaddr, vb->planes[plane_no].mem_priv);
+	return call_ptr_memop(vaddr, vb, vb->planes[plane_no].mem_priv);
 
 }
 EXPORT_SYMBOL_GPL(vb2_plane_vaddr);
@@ -985,7 +986,7 @@ void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no)
 	if (plane_no >= vb->num_planes || !vb->planes[plane_no].mem_priv)
 		return NULL;
 
-	return call_ptr_memop(vb, cookie, vb->planes[plane_no].mem_priv);
+	return call_ptr_memop(cookie, vb, vb->planes[plane_no].mem_priv);
 }
 EXPORT_SYMBOL_GPL(vb2_plane_cookie);
 
@@ -1125,10 +1126,11 @@ static int __prepare_userptr(struct vb2_buffer *vb)
 		vb->planes[plane].data_offset = 0;
 
 		/* Acquire each plane's memory */
-		mem_priv = call_ptr_memop(vb, get_userptr,
-				q->alloc_devs[plane] ? : q->dev,
-				planes[plane].m.userptr,
-				planes[plane].length, q->dma_dir);
+		mem_priv = call_ptr_memop(get_userptr,
+					  vb,
+					  q->alloc_devs[plane] ? : q->dev,
+					  planes[plane].m.userptr,
+					  planes[plane].length);
 		if (IS_ERR(mem_priv)) {
 			dprintk(q, 1, "failed acquiring userspace memory for plane %d\n",
 				plane);
@@ -1249,9 +1251,11 @@ static int __prepare_dmabuf(struct vb2_buffer *vb)
 		vb->planes[plane].data_offset = 0;
 
 		/* Acquire each plane's memory */
-		mem_priv = call_ptr_memop(vb, attach_dmabuf,
-				q->alloc_devs[plane] ? : q->dev,
-				dbuf, planes[plane].length, q->dma_dir);
+		mem_priv = call_ptr_memop(attach_dmabuf,
+					  vb,
+					  q->alloc_devs[plane] ? : q->dev,
+					  dbuf,
+					  planes[plane].length);
 		if (IS_ERR(mem_priv)) {
 			dprintk(q, 1, "failed to attach dmabuf\n");
 			ret = PTR_ERR(mem_priv);
@@ -2197,8 +2201,10 @@ int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type,
 
 	vb_plane = &vb->planes[plane];
 
-	dbuf = call_ptr_memop(vb, get_dmabuf, vb_plane->mem_priv,
-				flags & O_ACCMODE);
+	dbuf = call_ptr_memop(get_dmabuf,
+			      vb,
+			      vb_plane->mem_priv,
+			      flags & O_ACCMODE);
 	if (IS_ERR_OR_NULL(dbuf)) {
 		dprintk(q, 1, "failed to export buffer %d, plane %d\n",
 			index, plane);
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index a7f61ba85440..019c3843dc6d 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -40,6 +40,8 @@ struct vb2_dc_buf {
 
 	/* DMABUF related */
 	struct dma_buf_attachment	*db_attach;
+
+	struct vb2_buffer		*vb;
 };
 
 /*********************************************/
@@ -66,14 +68,14 @@ static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
 /*         callbacks for all buffers         */
 /*********************************************/
 
-static void *vb2_dc_cookie(void *buf_priv)
+static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv)
 {
 	struct vb2_dc_buf *buf = buf_priv;
 
 	return &buf->dma_addr;
 }
 
-static void *vb2_dc_vaddr(void *buf_priv)
+static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
 {
 	struct vb2_dc_buf *buf = buf_priv;
 	struct dma_buf_map map;
@@ -137,9 +139,9 @@ static void vb2_dc_put(void *buf_priv)
 	kfree(buf);
 }
 
-static void *vb2_dc_alloc(struct device *dev, unsigned long attrs,
-			  unsigned long size, enum dma_data_direction dma_dir,
-			  gfp_t gfp_flags)
+static void *vb2_dc_alloc(struct vb2_buffer *vb,
+			  struct device *dev,
+			  unsigned long size)
 {
 	struct vb2_dc_buf *buf;
 
@@ -150,9 +152,10 @@ static void *vb2_dc_alloc(struct device *dev, unsigned long attrs,
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 
-	buf->attrs = attrs;
+	buf->attrs = vb->vb2_queue->dma_attrs;
 	buf->cookie = dma_alloc_attrs(dev, size, &buf->dma_addr,
-					GFP_KERNEL | gfp_flags, buf->attrs);
+				      GFP_KERNEL | vb->vb2_queue->gfp_flags,
+				      buf->attrs);
 	if (!buf->cookie) {
 		dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
 		kfree(buf);
@@ -165,11 +168,12 @@ static void *vb2_dc_alloc(struct device *dev, unsigned long attrs,
 	/* Prevent the device from being released while the buffer is used */
 	buf->dev = get_device(dev);
 	buf->size = size;
-	buf->dma_dir = dma_dir;
+	buf->dma_dir = vb->vb2_queue->dma_dir;
 
 	buf->handler.refcount = &buf->refcount;
 	buf->handler.put = vb2_dc_put;
 	buf->handler.arg = buf;
+	buf->vb = vb;
 
 	refcount_set(&buf->refcount, 1);
 
@@ -397,7 +401,9 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
 	return sgt;
 }
 
-static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags)
+static struct dma_buf *vb2_dc_get_dmabuf(struct vb2_buffer *vb,
+					 void *buf_priv,
+					 unsigned long flags)
 {
 	struct vb2_dc_buf *buf = buf_priv;
 	struct dma_buf *dbuf;
@@ -459,8 +465,8 @@ static void vb2_dc_put_userptr(void *buf_priv)
 	kfree(buf);
 }
 
-static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
-	unsigned long size, enum dma_data_direction dma_dir)
+static void *vb2_dc_get_userptr(struct vb2_buffer *vb, struct device *dev,
+				unsigned long vaddr, unsigned long size)
 {
 	struct vb2_dc_buf *buf;
 	struct frame_vector *vec;
@@ -490,7 +496,7 @@ static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
 		return ERR_PTR(-ENOMEM);
 
 	buf->dev = dev;
-	buf->dma_dir = dma_dir;
+	buf->dma_dir = vb->vb2_queue->dma_dir;
 
 	offset = lower_32_bits(offset_in_page(vaddr));
 	vec = vb2_create_framevec(vaddr, size);
@@ -660,8 +666,8 @@ static void vb2_dc_detach_dmabuf(void *mem_priv)
 	kfree(buf);
 }
 
-static void *vb2_dc_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
-	unsigned long size, enum dma_data_direction dma_dir)
+static void *vb2_dc_attach_dmabuf(struct vb2_buffer *vb, struct device *dev,
+				  struct dma_buf *dbuf, unsigned long size)
 {
 	struct vb2_dc_buf *buf;
 	struct dma_buf_attachment *dba;
@@ -685,7 +691,7 @@ static void *vb2_dc_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
 		return dba;
 	}
 
-	buf->dma_dir = dma_dir;
+	buf->dma_dir = vb->vb2_queue->dma_dir;
 	buf->size = size;
 	buf->db_attach = dba;
 
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
index c5b06a509566..50265080cfc8 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
@@ -51,6 +51,8 @@ struct vb2_dma_sg_buf {
 	struct vb2_vmarea_handler	handler;
 
 	struct dma_buf_attachment	*db_attach;
+
+	struct vb2_buffer		*vb;
 };
 
 static void vb2_dma_sg_put(void *buf_priv);
@@ -96,9 +98,8 @@ static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
 	return 0;
 }
 
-static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
-			      unsigned long size, enum dma_data_direction dma_dir,
-			      gfp_t gfp_flags)
+static void *vb2_dma_sg_alloc(struct vb2_buffer *vb, struct device *dev,
+			      unsigned long size)
 {
 	struct vb2_dma_sg_buf *buf;
 	struct sg_table *sgt;
@@ -113,7 +114,7 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
 		return ERR_PTR(-ENOMEM);
 
 	buf->vaddr = NULL;
-	buf->dma_dir = dma_dir;
+	buf->dma_dir = vb->vb2_queue->dma_dir;
 	buf->offset = 0;
 	buf->size = size;
 	/* size is already page aligned */
@@ -130,7 +131,7 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
 	if (!buf->pages)
 		goto fail_pages_array_alloc;
 
-	ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
+	ret = vb2_dma_sg_alloc_compacted(buf, vb->vb2_queue->gfp_flags);
 	if (ret)
 		goto fail_pages_alloc;
 
@@ -154,6 +155,7 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
 	buf->handler.refcount = &buf->refcount;
 	buf->handler.put = vb2_dma_sg_put;
 	buf->handler.arg = buf;
+	buf->vb = vb;
 
 	refcount_set(&buf->refcount, 1);
 
@@ -213,9 +215,8 @@ static void vb2_dma_sg_finish(void *buf_priv)
 	dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
 }
 
-static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
-				    unsigned long size,
-				    enum dma_data_direction dma_dir)
+static void *vb2_dma_sg_get_userptr(struct vb2_buffer *vb, struct device *dev,
+				    unsigned long vaddr, unsigned long size)
 {
 	struct vb2_dma_sg_buf *buf;
 	struct sg_table *sgt;
@@ -230,7 +231,7 @@ 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_dir = vb->vb2_queue->dma_dir;
 	buf->offset = vaddr & ~PAGE_MASK;
 	buf->size = size;
 	buf->dma_sgt = &buf->sg_table;
@@ -292,7 +293,7 @@ static void vb2_dma_sg_put_userptr(void *buf_priv)
 	kfree(buf);
 }
 
-static void *vb2_dma_sg_vaddr(void *buf_priv)
+static void *vb2_dma_sg_vaddr(struct vb2_buffer *vb, void *buf_priv)
 {
 	struct vb2_dma_sg_buf *buf = buf_priv;
 	struct dma_buf_map map;
@@ -511,7 +512,9 @@ static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
 	.release = vb2_dma_sg_dmabuf_ops_release,
 };
 
-static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
+static struct dma_buf *vb2_dma_sg_get_dmabuf(struct vb2_buffer *vb,
+					     void *buf_priv,
+					     unsigned long flags)
 {
 	struct vb2_dma_sg_buf *buf = buf_priv;
 	struct dma_buf *dbuf;
@@ -605,8 +608,8 @@ static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
 	kfree(buf);
 }
 
-static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
-	unsigned long size, enum dma_data_direction dma_dir)
+static void *vb2_dma_sg_attach_dmabuf(struct vb2_buffer *vb, struct device *dev,
+				      struct dma_buf *dbuf, unsigned long size)
 {
 	struct vb2_dma_sg_buf *buf;
 	struct dma_buf_attachment *dba;
@@ -630,14 +633,14 @@ static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
 		return dba;
 	}
 
-	buf->dma_dir = dma_dir;
+	buf->dma_dir = vb->vb2_queue->dma_dir;
 	buf->size = size;
 	buf->db_attach = dba;
 
 	return buf;
 }
 
-static void *vb2_dma_sg_cookie(void *buf_priv)
+static void *vb2_dma_sg_cookie(struct vb2_buffer *vb, void *buf_priv)
 {
 	struct vb2_dma_sg_buf *buf = buf_priv;
 
diff --git a/drivers/media/common/videobuf2/videobuf2-vmalloc.c b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
index 83f95258ec8c..ef36abd912dc 100644
--- a/drivers/media/common/videobuf2/videobuf2-vmalloc.c
+++ b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
@@ -34,13 +34,12 @@ struct vb2_vmalloc_buf {
 
 static void vb2_vmalloc_put(void *buf_priv);
 
-static void *vb2_vmalloc_alloc(struct device *dev, unsigned long attrs,
-			       unsigned long size, enum dma_data_direction dma_dir,
-			       gfp_t gfp_flags)
+static void *vb2_vmalloc_alloc(struct vb2_buffer *vb, struct device *dev,
+			       unsigned long size)
 {
 	struct vb2_vmalloc_buf *buf;
 
-	buf = kzalloc(sizeof(*buf), GFP_KERNEL | gfp_flags);
+	buf = kzalloc(sizeof(*buf), GFP_KERNEL | vb->vb2_queue->gfp_flags);
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 
@@ -52,7 +51,7 @@ static void *vb2_vmalloc_alloc(struct device *dev, unsigned long attrs,
 		return ERR_PTR(-ENOMEM);
 	}
 
-	buf->dma_dir = dma_dir;
+	buf->dma_dir = vb->vb2_queue->dma_dir;
 	buf->handler.refcount = &buf->refcount;
 	buf->handler.put = vb2_vmalloc_put;
 	buf->handler.arg = buf;
@@ -71,9 +70,8 @@ static void vb2_vmalloc_put(void *buf_priv)
 	}
 }
 
-static void *vb2_vmalloc_get_userptr(struct device *dev, unsigned long vaddr,
-				     unsigned long size,
-				     enum dma_data_direction dma_dir)
+static void *vb2_vmalloc_get_userptr(struct vb2_buffer *vb, struct device *dev,
+				     unsigned long vaddr, unsigned long size)
 {
 	struct vb2_vmalloc_buf *buf;
 	struct frame_vector *vec;
@@ -84,7 +82,7 @@ static void *vb2_vmalloc_get_userptr(struct device *dev, unsigned long vaddr,
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 
-	buf->dma_dir = dma_dir;
+	buf->dma_dir = vb->vb2_queue->dma_dir;
 	offset = vaddr & ~PAGE_MASK;
 	buf->size = size;
 	vec = vb2_create_framevec(vaddr, size);
@@ -147,7 +145,7 @@ static void vb2_vmalloc_put_userptr(void *buf_priv)
 	kfree(buf);
 }
 
-static void *vb2_vmalloc_vaddr(void *buf_priv)
+static void *vb2_vmalloc_vaddr(struct vb2_buffer *vb, void *buf_priv)
 {
 	struct vb2_vmalloc_buf *buf = buf_priv;
 
@@ -339,7 +337,9 @@ static const struct dma_buf_ops vb2_vmalloc_dmabuf_ops = {
 	.release = vb2_vmalloc_dmabuf_ops_release,
 };
 
-static struct dma_buf *vb2_vmalloc_get_dmabuf(void *buf_priv, unsigned long flags)
+static struct dma_buf *vb2_vmalloc_get_dmabuf(struct vb2_buffer *vb,
+					      void *buf_priv,
+					      unsigned long flags)
 {
 	struct vb2_vmalloc_buf *buf = buf_priv;
 	struct dma_buf *dbuf;
@@ -403,8 +403,10 @@ static void vb2_vmalloc_detach_dmabuf(void *mem_priv)
 	kfree(buf);
 }
 
-static void *vb2_vmalloc_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
-	unsigned long size, enum dma_data_direction dma_dir)
+static void *vb2_vmalloc_attach_dmabuf(struct vb2_buffer *vb,
+				       struct device *dev,
+				       struct dma_buf *dbuf,
+				       unsigned long size)
 {
 	struct vb2_vmalloc_buf *buf;
 
@@ -416,7 +418,7 @@ static void *vb2_vmalloc_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
 		return ERR_PTR(-ENOMEM);
 
 	buf->dbuf = dbuf;
-	buf->dma_dir = dma_dir;
+	buf->dma_dir = vb->vb2_queue->dma_dir;
 	buf->size = size;
 
 	return buf;
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 12955cb460d2..3b5986cee073 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -46,6 +46,7 @@ enum vb2_memory {
 
 struct vb2_fileio_data;
 struct vb2_threadio_data;
+struct vb2_buffer;
 
 /**
  * struct vb2_mem_ops - memory handling/memory allocator operations.
@@ -53,10 +54,8 @@ struct vb2_threadio_data;
  *		return ERR_PTR() on failure or a pointer to allocator private,
  *		per-buffer data on success; the returned private structure
  *		will then be passed as @buf_priv argument to other ops in this
- *		structure. Additional gfp_flags to use when allocating the
- *		are also passed to this operation. These flags are from the
- *		gfp_flags field of vb2_queue. The size argument to this function
- *		shall be *page aligned*.
+ *		structure. The size argument to this function shall be
+ *		*page aligned*.
  * @put:	inform the allocator that the buffer will no longer be used;
  *		usually will result in the allocator freeing the buffer (if
  *		no other users of this buffer are present); the @buf_priv
@@ -117,31 +116,33 @@ struct vb2_threadio_data;
  *       map_dmabuf, unmap_dmabuf.
  */
 struct vb2_mem_ops {
-	void		*(*alloc)(struct device *dev, unsigned long attrs,
-				  unsigned long size,
-				  enum dma_data_direction dma_dir,
-				  gfp_t gfp_flags);
+	void		*(*alloc)(struct vb2_buffer *vb,
+				  struct device *dev,
+				  unsigned long size);
 	void		(*put)(void *buf_priv);
-	struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags);
-
-	void		*(*get_userptr)(struct device *dev, unsigned long vaddr,
-					unsigned long size,
-					enum dma_data_direction dma_dir);
+	struct dma_buf *(*get_dmabuf)(struct vb2_buffer *vb,
+				      void *buf_priv,
+				      unsigned long flags);
+
+	void		*(*get_userptr)(struct vb2_buffer *vb,
+					struct device *dev,
+					unsigned long vaddr,
+					unsigned long size);
 	void		(*put_userptr)(void *buf_priv);
 
 	void		(*prepare)(void *buf_priv);
 	void		(*finish)(void *buf_priv);
 
-	void		*(*attach_dmabuf)(struct device *dev,
+	void		*(*attach_dmabuf)(struct vb2_buffer *vb,
+					  struct device *dev,
 					  struct dma_buf *dbuf,
-					  unsigned long size,
-					  enum dma_data_direction dma_dir);
+					  unsigned long size);
 	void		(*detach_dmabuf)(void *buf_priv);
 	int		(*map_dmabuf)(void *buf_priv);
 	void		(*unmap_dmabuf)(void *buf_priv);
 
-	void		*(*vaddr)(void *buf_priv);
-	void		*(*cookie)(void *buf_priv);
+	void		*(*vaddr)(struct vb2_buffer *vb, void *buf_priv);
+	void		*(*cookie)(struct vb2_buffer *vb, void *buf_priv);
 
 	unsigned int	(*num_users)(void *buf_priv);
 
-- 
2.33.0.153.gba50c8fa24-goog

[PATCHv6 2/8] videobuf2: inverse buffer cache_hints flags

[Sergey Senozhatsky]

It would be less error prone if the default cache hints value
(we kzalloc() structs, so it's zeroed out by default) would be
to "always sync/flush" caches. Inverse and rename cache hints
flags.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 .../media/common/videobuf2/videobuf2-core.c   | 31 ++++++-------------
 .../media/common/videobuf2/videobuf2-v4l2.c   | 17 +++-------
 include/media/videobuf2-core.h                | 12 +++----
 3 files changed, 21 insertions(+), 39 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index c4ff356da600..9d57df348b5f 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -327,12 +327,12 @@ static void __vb2_buf_mem_prepare(struct vb2_buffer *vb)
 	if (vb->synced)
 		return;
 
-	if (vb->need_cache_sync_on_prepare) {
-		for (plane = 0; plane < vb->num_planes; ++plane)
-			call_void_memop(vb, prepare,
-					vb->planes[plane].mem_priv);
-	}
 	vb->synced = 1;
+	if (vb->skip_cache_sync_on_prepare)
+		return;
+
+	for (plane = 0; plane < vb->num_planes; ++plane)
+		call_void_memop(vb, prepare, vb->planes[plane].mem_priv);
 }
 
 /*
@@ -346,12 +346,12 @@ static void __vb2_buf_mem_finish(struct vb2_buffer *vb)
 	if (!vb->synced)
 		return;
 
-	if (vb->need_cache_sync_on_finish) {
-		for (plane = 0; plane < vb->num_planes; ++plane)
-			call_void_memop(vb, finish,
-					vb->planes[plane].mem_priv);
-	}
 	vb->synced = 0;
+	if (vb->skip_cache_sync_on_finish)
+		return;
+
+	for (plane = 0; plane < vb->num_planes; ++plane)
+		call_void_memop(vb, finish, vb->planes[plane].mem_priv);
 }
 
 /*
@@ -415,17 +415,6 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
 		vb->index = q->num_buffers + buffer;
 		vb->type = q->type;
 		vb->memory = memory;
-		/*
-		 * We need to set these flags here so that the videobuf2 core
-		 * will call ->prepare()/->finish() cache sync/flush on vb2
-		 * buffers when appropriate. However, we can avoid explicit
-		 * ->prepare() and ->finish() cache sync for DMABUF buffers,
-		 * because DMA exporter takes care of it.
-		 */
-		if (q->memory != VB2_MEMORY_DMABUF) {
-			vb->need_cache_sync_on_prepare = 1;
-			vb->need_cache_sync_on_finish = 1;
-		}
 		for (plane = 0; plane < num_planes; ++plane) {
 			vb->planes[plane].length = plane_sizes[plane];
 			vb->planes[plane].min_length = plane_sizes[plane];
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 2988bb38ceb1..454d58268602 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -351,18 +351,11 @@ static void set_buffer_cache_hints(struct vb2_queue *q,
 	 * we always need ->prepare() or/and ->finish() cache sync.
 	 */
 	if (q->memory == VB2_MEMORY_DMABUF) {
-		vb->need_cache_sync_on_finish = 0;
-		vb->need_cache_sync_on_prepare = 0;
+		vb->skip_cache_sync_on_finish = 1;
+		vb->skip_cache_sync_on_prepare = 1;
 		return;
 	}
 
-	/*
-	 * Cache sync/invalidation flags are set by default in order to
-	 * preserve existing behaviour for old apps/drivers.
-	 */
-	vb->need_cache_sync_on_prepare = 1;
-	vb->need_cache_sync_on_finish = 1;
-
 	if (!vb2_queue_allows_cache_hints(q)) {
 		/*
 		 * Clear buffer cache flags if queue does not support user
@@ -379,13 +372,13 @@ static void set_buffer_cache_hints(struct vb2_queue *q,
 	 * TO_DEVICE.
 	 */
 	if (q->dma_dir == DMA_TO_DEVICE)
-		vb->need_cache_sync_on_finish = 0;
+		vb->skip_cache_sync_on_finish = 1;
 
 	if (b->flags & V4L2_BUF_FLAG_NO_CACHE_INVALIDATE)
-		vb->need_cache_sync_on_finish = 0;
+		vb->skip_cache_sync_on_finish = 1;
 
 	if (b->flags & V4L2_BUF_FLAG_NO_CACHE_CLEAN)
-		vb->need_cache_sync_on_prepare = 0;
+		vb->skip_cache_sync_on_prepare = 1;
 }
 
 static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *mdev,
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 3b5986cee073..66e548268242 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -267,10 +267,10 @@ struct vb2_buffer {
 	 *			after the 'buf_finish' op is called.
 	 * copied_timestamp:	the timestamp of this capture buffer was copied
 	 *			from an output buffer.
-	 * need_cache_sync_on_prepare: when set buffer's ->prepare() function
-	 *			performs cache sync/invalidation.
-	 * need_cache_sync_on_finish: when set buffer's ->finish() function
-	 *			performs cache sync/invalidation.
+	 * skip_cache_sync_on_prepare: when set buffer's ->prepare() function
+	 *			skips cache sync/invalidation.
+	 * skip_cache_sync_on_finish: when set buffer's ->finish() function
+	 *			skips cache sync/invalidation.
 	 * queued_entry:	entry on the queued buffers list, which holds
 	 *			all buffers queued from userspace
 	 * done_entry:		entry on the list that stores all buffers ready
@@ -281,8 +281,8 @@ struct vb2_buffer {
 	unsigned int		synced:1;
 	unsigned int		prepared:1;
 	unsigned int		copied_timestamp:1;
-	unsigned int		need_cache_sync_on_prepare:1;
-	unsigned int		need_cache_sync_on_finish:1;
+	unsigned int		skip_cache_sync_on_prepare:1;
+	unsigned int		skip_cache_sync_on_finish:1;
 
 	struct vb2_plane	planes[VB2_MAX_PLANES];
 	struct list_head	queued_entry;
-- 
2.33.0.153.gba50c8fa24-goog

[PATCHv6 3/8] videobuf2: split buffer cache_hints initialisation

[Sergey Senozhatsky]

V4L2 is not the perfect place to manage vb2 buffer cache hints.
It works for V4L2 users, but there are backends that use vb2 core
and don't use V4L2. Factor out buffer cache hints initialisation
and call it when we allocate vb2 buffer.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 .../media/common/videobuf2/videobuf2-core.c   | 22 +++++++++++++++++++
 .../media/common/videobuf2/videobuf2-v4l2.c   | 18 ---------------
 2 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 9d57df348b5f..59bd781c9a34 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -382,6 +382,27 @@ static void __setup_offsets(struct vb2_buffer *vb)
 	}
 }
 
+static void init_buffer_cache_hints(struct vb2_queue *q, struct vb2_buffer *vb)
+{
+	/*
+	 * DMA exporter should take care of cache syncs, so we can avoid
+	 * explicit ->prepare()/->finish() syncs. For other ->memory types
+	 * we always need ->prepare() or/and ->finish() cache sync.
+	 */
+	if (q->memory == VB2_MEMORY_DMABUF) {
+		vb->skip_cache_sync_on_finish = 1;
+		vb->skip_cache_sync_on_prepare = 1;
+		return;
+	}
+
+	/*
+	 * ->finish() cache sync can be avoided when queue direction is
+	 * TO_DEVICE.
+	 */
+	if (q->dma_dir == DMA_TO_DEVICE)
+		vb->skip_cache_sync_on_finish = 1;
+}
+
 /*
  * __vb2_queue_alloc() - allocate videobuf buffer structures and (for MMAP type)
  * video buffer memory for all buffers/planes on the queue and initializes the
@@ -415,6 +436,7 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
 		vb->index = q->num_buffers + buffer;
 		vb->type = q->type;
 		vb->memory = memory;
+		init_buffer_cache_hints(q, vb);
 		for (plane = 0; plane < num_planes; ++plane) {
 			vb->planes[plane].length = plane_sizes[plane];
 			vb->planes[plane].min_length = plane_sizes[plane];
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 454d58268602..2fbae9bd7b52 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -345,17 +345,6 @@ static void set_buffer_cache_hints(struct vb2_queue *q,
 				   struct vb2_buffer *vb,
 				   struct v4l2_buffer *b)
 {
-	/*
-	 * DMA exporter should take care of cache syncs, so we can avoid
-	 * explicit ->prepare()/->finish() syncs. For other ->memory types
-	 * we always need ->prepare() or/and ->finish() cache sync.
-	 */
-	if (q->memory == VB2_MEMORY_DMABUF) {
-		vb->skip_cache_sync_on_finish = 1;
-		vb->skip_cache_sync_on_prepare = 1;
-		return;
-	}
-
 	if (!vb2_queue_allows_cache_hints(q)) {
 		/*
 		 * Clear buffer cache flags if queue does not support user
@@ -367,13 +356,6 @@ static void set_buffer_cache_hints(struct vb2_queue *q,
 		return;
 	}
 
-	/*
-	 * ->finish() cache sync can be avoided when queue direction is
-	 * TO_DEVICE.
-	 */
-	if (q->dma_dir == DMA_TO_DEVICE)
-		vb->skip_cache_sync_on_finish = 1;
-
 	if (b->flags & V4L2_BUF_FLAG_NO_CACHE_INVALIDATE)
 		vb->skip_cache_sync_on_finish = 1;
 
-- 
2.33.0.153.gba50c8fa24-goog

[PATCHv6 4/8] videobuf2: move cache_hints handling to allocators

[Sergey Senozhatsky]

This moves cache hints handling from the videobuf2 core down
to the allocator's level, because allocators do the sync/flush
caches eventually and may take better decisions. Besides,
allocators already decide whether cache sync/flush should
be done or can be skipped. This patch moves the scattered
buffer cache sync logic to one common place.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 drivers/media/common/videobuf2/videobuf2-core.c       | 6 ------
 drivers/media/common/videobuf2/videobuf2-dma-contig.c | 6 ++++++
 drivers/media/common/videobuf2/videobuf2-dma-sg.c     | 6 ++++++
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 59bd781c9a34..8fa9f92ed028 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -328,9 +328,6 @@ static void __vb2_buf_mem_prepare(struct vb2_buffer *vb)
 		return;
 
 	vb->synced = 1;
-	if (vb->skip_cache_sync_on_prepare)
-		return;
-
 	for (plane = 0; plane < vb->num_planes; ++plane)
 		call_void_memop(vb, prepare, vb->planes[plane].mem_priv);
 }
@@ -347,9 +344,6 @@ static void __vb2_buf_mem_finish(struct vb2_buffer *vb)
 		return;
 
 	vb->synced = 0;
-	if (vb->skip_cache_sync_on_finish)
-		return;
-
 	for (plane = 0; plane < vb->num_planes; ++plane)
 		call_void_memop(vb, finish, vb->planes[plane].mem_priv);
 }
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index 019c3843dc6d..1e218bc440c6 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -101,6 +101,9 @@ static void vb2_dc_prepare(void *buf_priv)
 	struct vb2_dc_buf *buf = buf_priv;
 	struct sg_table *sgt = buf->dma_sgt;
 
+	if (buf->vb->skip_cache_sync_on_prepare)
+		return;
+
 	if (!sgt)
 		return;
 
@@ -112,6 +115,9 @@ static void vb2_dc_finish(void *buf_priv)
 	struct vb2_dc_buf *buf = buf_priv;
 	struct sg_table *sgt = buf->dma_sgt;
 
+	if (buf->vb->skip_cache_sync_on_finish)
+		return;
+
 	if (!sgt)
 		return;
 
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
index 50265080cfc8..33ee63a99139 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
@@ -204,6 +204,9 @@ static void vb2_dma_sg_prepare(void *buf_priv)
 	struct vb2_dma_sg_buf *buf = buf_priv;
 	struct sg_table *sgt = buf->dma_sgt;
 
+	if (buf->vb->skip_cache_sync_on_prepare)
+		return;
+
 	dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
 }
 
@@ -212,6 +215,9 @@ static void vb2_dma_sg_finish(void *buf_priv)
 	struct vb2_dma_sg_buf *buf = buf_priv;
 	struct sg_table *sgt = buf->dma_sgt;
 
+	if (buf->vb->skip_cache_sync_on_finish)
+		return;
+
 	dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
 }
 
-- 
2.33.0.153.gba50c8fa24-goog

[PATCHv6 5/8] videobuf2: add V4L2_MEMORY_FLAG_NON_COHERENT flag

[Sergey Senozhatsky]

By setting or clearing the V4L2_MEMORY_FLAG_NON_COHERENT flag
user-space should be able to hint vb2 that either non-coherent
(if supported) or coherent memory should be used for the buffer
allocation.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 .../userspace-api/media/v4l/buffer.rst        | 40 ++++++++++++++++++-
 .../media/v4l/vidioc-reqbufs.rst              |  5 ++-
 include/uapi/linux/videodev2.h                |  2 +
 3 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst
index e991ba73d873..4638ec64db00 100644
--- a/Documentation/userspace-api/media/v4l/buffer.rst
+++ b/Documentation/userspace-api/media/v4l/buffer.rst
@@ -676,8 +676,6 @@ Buffer Flags
 
     \normalsize
 
-.. _memory-flags:
-
 enum v4l2_memory
 ================
 
@@ -701,6 +699,44 @@ enum v4l2_memory
       - 4
       - The buffer is used for :ref:`DMA shared buffer <dmabuf>` I/O.
 
+.. _memory-flags:
+
+Memory Consistency Flags
+------------------------
+
+.. raw:: latex
+
+    \small
+
+.. tabularcolumns:: |p{7.0cm}|p{2.1cm}|p{8.4cm}|
+
+.. cssclass:: longtable
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       3 1 4
+
+    * .. _`V4L2-MEMORY-FLAG-NON-COHERENT`:
+
+      - ``V4L2_MEMORY_FLAG_NON_COHERENT``
+      - 0x00000001
+      - A buffer is allocated either in coherent (it will be automatically
+	coherent between the CPU and the bus) or non-coherent memory. The
+	latter can provide performance gains, for instance the CPU cache
+	sync/flush operations can be avoided if the buffer is accessed by the
+	corresponding device only and the CPU does not read/write to/from that
+	buffer. However, this requires extra care from the driver -- it must
+	guarantee memory consistency by issuing a cache flush/sync when
+	consistency is needed. If this flag is set V4L2 will attempt to
+	allocate the buffer in non-coherent memory. The flag takes effect
+	only if the buffer is used for :ref:`memory mapping <mmap>` I/O and the
+	queue reports the :ref:`V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS
+	<V4L2-BUF-CAP-SUPPORTS-MMAP-CACHE-HINTS>` capability.
+
+.. raw:: latex
+
+    \normalsize
 
 Timecodes
 =========
diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
index 50ea72043bb0..e59306aba2b0 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
@@ -158,8 +158,9 @@ aborting or finishing any DMA in progress, an implicit
       - This capability is set by the driver to indicate that the queue supports
         cache and memory management hints. However, it's only valid when the
         queue is used for :ref:`memory mapping <mmap>` streaming I/O. See
-        :ref:`V4L2_BUF_FLAG_NO_CACHE_INVALIDATE <V4L2-BUF-FLAG-NO-CACHE-INVALIDATE>` and
-        :ref:`V4L2_BUF_FLAG_NO_CACHE_CLEAN <V4L2-BUF-FLAG-NO-CACHE-CLEAN>`.
+        :ref:`V4L2_BUF_FLAG_NO_CACHE_INVALIDATE <V4L2-BUF-FLAG-NO-CACHE-INVALIDATE>`,
+        :ref:`V4L2_BUF_FLAG_NO_CACHE_CLEAN <V4L2-BUF-FLAG-NO-CACHE-CLEAN>` and
+        :ref:`V4L2_MEMORY_FLAG_NON_COHERENT <V4L2-MEMORY-FLAG-NON-COHERENT>`.
 
 .. raw:: latex
 
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 5cc9545feb40..9b7032abb2c7 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -962,6 +962,8 @@ struct v4l2_requestbuffers {
 	__u32			reserved[1];
 };
 
+#define V4L2_MEMORY_FLAG_NON_COHERENT			(1 << 0)
+
 /* capabilities for struct v4l2_requestbuffers and v4l2_create_buffers */
 #define V4L2_BUF_CAP_SUPPORTS_MMAP			(1 << 0)
 #define V4L2_BUF_CAP_SUPPORTS_USERPTR			(1 << 1)
-- 
2.33.0.153.gba50c8fa24-goog

[PATCHv6 6/8] videobuf2: add queue memory coherency parameter

[Sergey Senozhatsky]

Preparations for future V4L2_MEMORY_FLAG_NON_COHERENT support.

Extend the vb2_core_reqbufs() parameters list to accept requests'
->flags, which will be used for memory coherency configuration.

An attempt to allocate a buffer with coherency requirements
that do not match the queue's consistency model will fail.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 .../media/common/videobuf2/videobuf2-core.c   | 37 ++++++++++++++++---
 .../media/common/videobuf2/videobuf2-v4l2.c   |  5 ++-
 drivers/media/dvb-core/dvb_vb2.c              |  2 +-
 include/media/videobuf2-core.h                | 10 ++++-
 4 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 8fa9f92ed028..60fb43b8f134 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -738,11 +738,30 @@ int vb2_verify_memory_type(struct vb2_queue *q,
 }
 EXPORT_SYMBOL(vb2_verify_memory_type);
 
+static void set_queue_coherency(struct vb2_queue *q, bool non_coherent_mem)
+{
+	q->non_coherent_mem = 0;
+
+	if (!vb2_queue_allows_cache_hints(q))
+		return;
+	q->non_coherent_mem = non_coherent_mem;
+}
+
+static bool verify_coherency_flags(struct vb2_queue *q, bool non_coherent_mem)
+{
+	if (non_coherent_mem != q->non_coherent_mem) {
+		dprintk(q, 1, "memory coherency model mismatch\n");
+		return false;
+	}
+	return true;
+}
+
 int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
-		     unsigned int *count)
+		     unsigned int flags, unsigned int *count)
 {
 	unsigned int num_buffers, allocated_buffers, num_planes = 0;
 	unsigned plane_sizes[VB2_MAX_PLANES] = { };
+	bool non_coherent_mem = false;
 	unsigned int i;
 	int ret;
 
@@ -757,7 +776,8 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 	}
 
 	if (*count == 0 || q->num_buffers != 0 ||
-	    (q->memory != VB2_MEMORY_UNKNOWN && q->memory != memory)) {
+	    (q->memory != VB2_MEMORY_UNKNOWN && q->memory != memory) ||
+	    !verify_coherency_flags(q, non_coherent_mem)) {
 		/*
 		 * We already have buffers allocated, so first check if they
 		 * are not in use and can be freed.
@@ -794,6 +814,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 	num_buffers = min_t(unsigned int, num_buffers, VB2_MAX_FRAME);
 	memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
 	q->memory = memory;
+	set_queue_coherency(q, non_coherent_mem);
 
 	/*
 	 * Ask the driver how many buffers and planes per buffer it requires.
@@ -878,12 +899,13 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 EXPORT_SYMBOL_GPL(vb2_core_reqbufs);
 
 int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
-			 unsigned int *count,
+			 unsigned int flags, unsigned int *count,
 			 unsigned int requested_planes,
 			 const unsigned int requested_sizes[])
 {
 	unsigned int num_planes = 0, num_buffers, allocated_buffers;
 	unsigned plane_sizes[VB2_MAX_PLANES] = { };
+	bool non_coherent_mem = false;
 	int ret;
 
 	if (q->num_buffers == VB2_MAX_FRAME) {
@@ -899,11 +921,14 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
 		memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
 		q->memory = memory;
 		q->waiting_for_buffers = !q->is_output;
+		set_queue_coherency(q, non_coherent_mem);
 	} else {
 		if (q->memory != memory) {
 			dprintk(q, 1, "memory model mismatch\n");
 			return -EINVAL;
 		}
+		if (!verify_coherency_flags(q, non_coherent_mem))
+			return -EINVAL;
 	}
 
 	num_buffers = min(*count, VB2_MAX_FRAME - q->num_buffers);
@@ -2608,7 +2633,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)
 	fileio->memory = VB2_MEMORY_MMAP;
 	fileio->type = q->type;
 	q->fileio = fileio;
-	ret = vb2_core_reqbufs(q, fileio->memory, &fileio->count);
+	ret = vb2_core_reqbufs(q, fileio->memory, 0, &fileio->count);
 	if (ret)
 		goto err_kfree;
 
@@ -2665,7 +2690,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)
 
 err_reqbufs:
 	fileio->count = 0;
-	vb2_core_reqbufs(q, fileio->memory, &fileio->count);
+	vb2_core_reqbufs(q, fileio->memory, 0, &fileio->count);
 
 err_kfree:
 	q->fileio = NULL;
@@ -2685,7 +2710,7 @@ static int __vb2_cleanup_fileio(struct vb2_queue *q)
 		vb2_core_streamoff(q, q->type);
 		q->fileio = NULL;
 		fileio->count = 0;
-		vb2_core_reqbufs(q, fileio->memory, &fileio->count);
+		vb2_core_reqbufs(q, fileio->memory, 0, &fileio->count);
 		kfree(fileio);
 		dprintk(q, 3, "file io emulator closed\n");
 	}
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 2fbae9bd7b52..b4f70ddb09b0 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -697,7 +697,7 @@ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
 	int ret = vb2_verify_memory_type(q, req->memory, req->type);
 
 	fill_buf_caps(q, &req->capabilities);
-	return ret ? ret : vb2_core_reqbufs(q, req->memory, &req->count);
+	return ret ? ret : vb2_core_reqbufs(q, req->memory, 0, &req->count);
 }
 EXPORT_SYMBOL_GPL(vb2_reqbufs);
 
@@ -772,6 +772,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
 		if (requested_sizes[i] == 0)
 			return -EINVAL;
 	return ret ? ret : vb2_core_create_bufs(q, create->memory,
+						0,
 						&create->count,
 						requested_planes,
 						requested_sizes);
@@ -974,7 +975,7 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
 		return res;
 	if (vb2_queue_is_busy(vdev, file))
 		return -EBUSY;
-	res = vb2_core_reqbufs(vdev->queue, p->memory, &p->count);
+	res = vb2_core_reqbufs(vdev->queue, p->memory, 0, &p->count);
 	/* If count == 0, then the owner has released all buffers and he
 	   is no longer owner of the queue. Otherwise we have a new owner. */
 	if (res == 0)
diff --git a/drivers/media/dvb-core/dvb_vb2.c b/drivers/media/dvb-core/dvb_vb2.c
index 6974f1731529..959d110407a4 100644
--- a/drivers/media/dvb-core/dvb_vb2.c
+++ b/drivers/media/dvb-core/dvb_vb2.c
@@ -342,7 +342,7 @@ int dvb_vb2_reqbufs(struct dvb_vb2_ctx *ctx, struct dmx_requestbuffers *req)
 
 	ctx->buf_siz = req->size;
 	ctx->buf_cnt = req->count;
-	ret = vb2_core_reqbufs(&ctx->vb_q, VB2_MEMORY_MMAP, &req->count);
+	ret = vb2_core_reqbufs(&ctx->vb_q, VB2_MEMORY_MMAP, 0, &req->count);
 	if (ret) {
 		ctx->state = DVB_VB2_STATE_NONE;
 		dprintk(1, "[%s] count=%d size=%d errno=%d\n", ctx->name,
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 66e548268242..2467284e5f26 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -504,6 +504,8 @@ struct vb2_buf_ops {
  * @allow_cache_hints: when set user-space can pass cache management hints in
  *		order to skip cache flush/invalidation on ->prepare() or/and
  *		->finish().
+ * @non_coherent_mem: when set queue will attempt to allocate buffers using
+ *		non-coherent memory.
  * @lock:	pointer to a mutex that protects the &struct vb2_queue. The
  *		driver can set this to a mutex to let the v4l2 core serialize
  *		the queuing ioctls. If the driver wants to handle locking
@@ -583,6 +585,7 @@ struct vb2_queue {
 	unsigned int			uses_qbuf:1;
 	unsigned int			uses_requests:1;
 	unsigned int			allow_cache_hints:1;
+	unsigned int			non_coherent_mem:1;
 
 	struct mutex			*lock;
 	void				*owner;
@@ -748,6 +751,8 @@ void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
  * vb2_core_reqbufs() - Initiate streaming.
  * @q:		pointer to &struct vb2_queue with videobuf2 queue.
  * @memory:	memory type, as defined by &enum vb2_memory.
+ * @flags:	auxiliary queue/buffer management flags. Currently, the only
+ *		used flag is %V4L2_MEMORY_FLAG_NON_COHERENT.
  * @count:	requested buffer count.
  *
  * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called
@@ -772,12 +777,13 @@ void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
  * Return: returns zero on success; an error code otherwise.
  */
 int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
-		    unsigned int *count);
+		     unsigned int flags, unsigned int *count);
 
 /**
  * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
  * @q: pointer to &struct vb2_queue with videobuf2 queue.
  * @memory: memory type, as defined by &enum vb2_memory.
+ * @flags: auxiliary queue/buffer management flags.
  * @count: requested buffer count.
  * @requested_planes: number of planes requested.
  * @requested_sizes: array with the size of the planes.
@@ -795,7 +801,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
  * Return: returns zero on success; an error code otherwise.
  */
 int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
-			 unsigned int *count,
+			 unsigned int flags, unsigned int *count,
 			 unsigned int requested_planes,
 			 const unsigned int requested_sizes[]);
 
-- 
2.33.0.153.gba50c8fa24-goog

[PATCHv6 7/8] videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag

[Sergey Senozhatsky]

This patch lets user-space request a non-coherent memory
allocation during CREATE_BUFS and REQBUFS ioctl calls.

= CREATE_BUFS

  struct v4l2_create_buffers has seven 4-byte reserved areas,
  so reserved[0] is renamed to ->flags. The struct, thus, now
  has six reserved 4-byte regions.

= CREATE_BUFS32

  struct v4l2_create_buffers32 has seven 4-byte reserved areas,
  so reserved[0] is renamed to ->flags. The struct, thus, now
  has six reserved 4-byte regions.

= REQBUFS

 We use one byte of a 4 byte ->reserved[1] member of struct
 v4l2_requestbuffers. The struct, thus, now has reserved 3 bytes.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 .../media/v4l/vidioc-create-bufs.rst          |  7 ++++-
 .../media/v4l/vidioc-reqbufs.rst              | 11 ++++---
 .../media/common/videobuf2/videobuf2-core.c   |  4 +--
 .../media/common/videobuf2/videobuf2-v4l2.c   | 31 +++++++++++++++++--
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c |  9 +++++-
 drivers/media/v4l2-core/v4l2-ioctl.c          |  4 +--
 include/uapi/linux/videodev2.h                |  9 ++++--
 7 files changed, 60 insertions(+), 15 deletions(-)

diff --git a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
index f98f18c9e91c..a048a9f6b7b6 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
@@ -113,7 +113,12 @@ than the number requested.
 	``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
 
     * - __u32
-      - ``reserved``\ [7]
+      - ``flags``
+      - Specifies additional buffer management attributes.
+	See :ref:`memory-flags`.
+
+    * - __u32
+      - ``reserved``\ [6]
       - A place holder for future extensions. Drivers and applications
 	must set the array to zero.
 
diff --git a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
index e59306aba2b0..099fa6695167 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
@@ -104,10 +104,13 @@ aborting or finishing any DMA in progress, an implicit
 	``V4L2_MEMORY_MMAP`` and ``type`` set to the buffer type. This will
 	free any previously allocated buffers, so this is typically something
 	that will be done at the start of the application.
-    * - __u32
-      - ``reserved``\ [1]
-      - A place holder for future extensions. Drivers and applications
-	must set the array to zero.
+    * - __u8
+      - ``flags``
+      - Specifies additional buffer management attributes.
+	See :ref:`memory-flags`.
+    * - __u8
+      - ``reserved``\ [3]
+      - Reserved for future extensions.
 
 .. _v4l2-buf-capabilities:
 .. _V4L2-BUF-CAP-SUPPORTS-MMAP:
diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 60fb43b8f134..2266bbd239ab 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -761,7 +761,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 {
 	unsigned int num_buffers, allocated_buffers, num_planes = 0;
 	unsigned plane_sizes[VB2_MAX_PLANES] = { };
-	bool non_coherent_mem = false;
+	bool non_coherent_mem = flags & V4L2_MEMORY_FLAG_NON_COHERENT;
 	unsigned int i;
 	int ret;
 
@@ -905,7 +905,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
 {
 	unsigned int num_planes = 0, num_buffers, allocated_buffers;
 	unsigned plane_sizes[VB2_MAX_PLANES] = { };
-	bool non_coherent_mem = false;
+	bool non_coherent_mem = flags & V4L2_MEMORY_FLAG_NON_COHERENT;
 	int ret;
 
 	if (q->num_buffers == VB2_MAX_FRAME) {
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index b4f70ddb09b0..6edf4508c636 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -692,12 +692,32 @@ static void fill_buf_caps(struct vb2_queue *q, u32 *caps)
 #endif
 }
 
+static void validate_memory_flags(struct vb2_queue *q,
+				  int memory,
+				  u32 *flags)
+{
+	if (!q->allow_cache_hints || memory != V4L2_MEMORY_MMAP) {
+		/*
+		 * This needs to clear V4L2_MEMORY_FLAG_NON_COHERENT only,
+		 * but in order to avoid bugs we zero out all bits.
+		 */
+		*flags = 0;
+	} else {
+		/* Clear all unknown flags. */
+		*flags &= V4L2_MEMORY_FLAG_NON_COHERENT;
+	}
+}
+
 int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
 {
 	int ret = vb2_verify_memory_type(q, req->memory, req->type);
+	u32 flags = req->flags;
 
 	fill_buf_caps(q, &req->capabilities);
-	return ret ? ret : vb2_core_reqbufs(q, req->memory, 0, &req->count);
+	validate_memory_flags(q, req->memory, &flags);
+	req->flags = flags;
+	return ret ? ret : vb2_core_reqbufs(q, req->memory,
+					    req->flags, &req->count);
 }
 EXPORT_SYMBOL_GPL(vb2_reqbufs);
 
@@ -729,6 +749,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
 	unsigned i;
 
 	fill_buf_caps(q, &create->capabilities);
+	validate_memory_flags(q, create->memory, &create->flags);
 	create->index = q->num_buffers;
 	if (create->count == 0)
 		return ret != -EBUSY ? ret : 0;
@@ -772,7 +793,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
 		if (requested_sizes[i] == 0)
 			return -EINVAL;
 	return ret ? ret : vb2_core_create_bufs(q, create->memory,
-						0,
+						create->flags,
 						&create->count,
 						requested_planes,
 						requested_sizes);
@@ -969,13 +990,16 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
 {
 	struct video_device *vdev = video_devdata(file);
 	int res = vb2_verify_memory_type(vdev->queue, p->memory, p->type);
+	u32 flags = p->flags;
 
 	fill_buf_caps(vdev->queue, &p->capabilities);
+	validate_memory_flags(vdev->queue, p->memory, &flags);
+	p->flags = flags;
 	if (res)
 		return res;
 	if (vb2_queue_is_busy(vdev, file))
 		return -EBUSY;
-	res = vb2_core_reqbufs(vdev->queue, p->memory, 0, &p->count);
+	res = vb2_core_reqbufs(vdev->queue, p->memory, p->flags, &p->count);
 	/* If count == 0, then the owner has released all buffers and he
 	   is no longer owner of the queue. Otherwise we have a new owner. */
 	if (res == 0)
@@ -993,6 +1017,7 @@ int vb2_ioctl_create_bufs(struct file *file, void *priv,
 
 	p->index = vdev->queue->num_buffers;
 	fill_buf_caps(vdev->queue, &p->capabilities);
+	validate_memory_flags(vdev->queue, p->memory, &p->flags);
 	/*
 	 * If count == 0, then just check if memory and type are valid.
 	 * Any -EBUSY result from vb2_verify_memory_type can be mapped to 0.
diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 47aff3b19742..8176769a89fa 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -126,6 +126,9 @@ struct v4l2_format32 {
  * @memory:	buffer memory type
  * @format:	frame format, for which buffers are requested
  * @capabilities: capabilities of this buffer type.
+ * @flags:	additional buffer management attributes (ignored unless the
+ *		queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability and
+ *		configured for MMAP streaming I/O).
  * @reserved:	future extensions
  */
 struct v4l2_create_buffers32 {
@@ -134,7 +137,8 @@ struct v4l2_create_buffers32 {
 	__u32			memory;	/* enum v4l2_memory */
 	struct v4l2_format32	format;
 	__u32			capabilities;
-	__u32			reserved[7];
+	__u32			flags;
+	__u32			reserved[6];
 };
 
 static int get_v4l2_format32(struct v4l2_format *p64,
@@ -182,6 +186,8 @@ static int get_v4l2_create32(struct v4l2_create_buffers *p64,
 	if (copy_from_user(p64, p32,
 			   offsetof(struct v4l2_create_buffers32, format)))
 		return -EFAULT;
+	if (copy_from_user(&p64->flags, &p32->flags, sizeof(p32->flags)))
+		return -EFAULT;
 	return get_v4l2_format32(&p64->format, &p32->format);
 }
 
@@ -227,6 +233,7 @@ static int put_v4l2_create32(struct v4l2_create_buffers *p64,
 	if (copy_to_user(p32, p64,
 			 offsetof(struct v4l2_create_buffers32, format)) ||
 	    put_user(p64->capabilities, &p32->capabilities) ||
+	    put_user(p64->flags, &p32->flags) ||
 	    copy_to_user(p32->reserved, p64->reserved, sizeof(p64->reserved)))
 		return -EFAULT;
 	return put_v4l2_format32(&p64->format, &p32->format);
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index d4f97ab1b237..842ad84490ca 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -2006,7 +2006,7 @@ static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops,
 	if (ret)
 		return ret;
 
-	CLEAR_AFTER_FIELD(p, capabilities);
+	CLEAR_AFTER_FIELD(p, flags);
 
 	return ops->vidioc_reqbufs(file, fh, p);
 }
@@ -2047,7 +2047,7 @@ static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops,
 	if (ret)
 		return ret;
 
-	CLEAR_AFTER_FIELD(create, capabilities);
+	CLEAR_AFTER_FIELD(create, flags);
 
 	v4l_sanitize_format(&create->format);
 
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 9b7032abb2c7..f118fe7a9f58 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -959,7 +959,8 @@ struct v4l2_requestbuffers {
 	__u32			type;		/* enum v4l2_buf_type */
 	__u32			memory;		/* enum v4l2_memory */
 	__u32			capabilities;
-	__u32			reserved[1];
+	__u8			flags;
+	__u8			reserved[3];
 };
 
 #define V4L2_MEMORY_FLAG_NON_COHERENT			(1 << 0)
@@ -2507,6 +2508,9 @@ struct v4l2_dbg_chip_info {
  * @memory:	enum v4l2_memory; buffer memory type
  * @format:	frame format, for which buffers are requested
  * @capabilities: capabilities of this buffer type.
+ * @flags:	additional buffer management attributes (ignored unless the
+ *		queue has V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS capability
+ *		and configured for MMAP streaming I/O).
  * @reserved:	future extensions
  */
 struct v4l2_create_buffers {
@@ -2515,7 +2519,8 @@ struct v4l2_create_buffers {
 	__u32			memory;
 	struct v4l2_format	format;
 	__u32			capabilities;
-	__u32			reserved[7];
+	__u32			flags;
+	__u32			reserved[6];
 };
 
 /*
-- 
2.33.0.153.gba50c8fa24-goog

[PATCHv6 8/8] videobuf2: handle non-contiguous DMA allocations

[Sergey Senozhatsky]

This adds support for the new noncontiguous DMA API, which
requires allocators to have two execution branches: one
for the current API, and one for the new one.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Christoph Hellwig <hch@lst.de>
---
 .../common/videobuf2/videobuf2-dma-contig.c   | 161 ++++++++++++++----
 1 file changed, 130 insertions(+), 31 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index 1e218bc440c6..b052a4e36961 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -17,6 +17,7 @@
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/dma-mapping.h>
+#include <linux/highmem.h>
 
 #include <media/videobuf2-v4l2.h>
 #include <media/videobuf2-dma-contig.h>
@@ -42,6 +43,7 @@ struct vb2_dc_buf {
 	struct dma_buf_attachment	*db_attach;
 
 	struct vb2_buffer		*vb;
+	bool				non_coherent_mem;
 };
 
 /*********************************************/
@@ -75,17 +77,39 @@ static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv)
 	return &buf->dma_addr;
 }
 
+/*
+ * This function may fail if:
+ *
+ * - dma_buf_vmap() fails
+ *   E.g. due to lack of virtual mapping address space, or due to
+ *   dmabuf->ops misconfiguration.
+ *
+ * - dma_vmap_noncontiguous() fails
+ *   For instance, when requested buffer size is larger than totalram_pages().
+ *   Relevant for buffers that use non-coherent memory.
+ *
+ * - Queue DMA attrs have DMA_ATTR_NO_KERNEL_MAPPING set
+ *   Relevant for buffers that use coherent memory.
+ */
 static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
 {
 	struct vb2_dc_buf *buf = buf_priv;
-	struct dma_buf_map map;
-	int ret;
 
-	if (!buf->vaddr && buf->db_attach) {
-		ret = dma_buf_vmap(buf->db_attach->dmabuf, &map);
-		buf->vaddr = ret ? NULL : map.vaddr;
+	if (buf->vaddr)
+		return buf->vaddr;
+
+	if (buf->db_attach) {
+		struct dma_buf_map map;
+
+		if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
+			buf->vaddr = map.vaddr;
+
+		return buf->vaddr;
 	}
 
+	if (buf->non_coherent_mem)
+		buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
+						    buf->dma_sgt);
 	return buf->vaddr;
 }
 
@@ -101,13 +125,19 @@ static void vb2_dc_prepare(void *buf_priv)
 	struct vb2_dc_buf *buf = buf_priv;
 	struct sg_table *sgt = buf->dma_sgt;
 
+	/* This takes care of DMABUF and user-enforced cache sync hint */
 	if (buf->vb->skip_cache_sync_on_prepare)
 		return;
 
-	if (!sgt)
+	if (!buf->non_coherent_mem)
 		return;
 
+	/* For both USERPTR and non-coherent MMAP */
 	dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
+
+	/* Non-coherent MMAP only */
+	if (buf->vaddr)
+		flush_kernel_vmap_range(buf->vaddr, buf->size);
 }
 
 static void vb2_dc_finish(void *buf_priv)
@@ -115,13 +145,19 @@ static void vb2_dc_finish(void *buf_priv)
 	struct vb2_dc_buf *buf = buf_priv;
 	struct sg_table *sgt = buf->dma_sgt;
 
+	/* This takes care of DMABUF and user-enforced cache sync hint */
 	if (buf->vb->skip_cache_sync_on_finish)
 		return;
 
-	if (!sgt)
+	if (!buf->non_coherent_mem)
 		return;
 
+	/* For both USERPTR and non-coherent MMAP */
 	dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
+
+	/* Non-coherent MMAP only */
+	if (buf->vaddr)
+		invalidate_kernel_vmap_range(buf->vaddr, buf->size);
 }
 
 /*********************************************/
@@ -135,21 +171,69 @@ static void vb2_dc_put(void *buf_priv)
 	if (!refcount_dec_and_test(&buf->refcount))
 		return;
 
-	if (buf->sgt_base) {
-		sg_free_table(buf->sgt_base);
-		kfree(buf->sgt_base);
+	if (buf->non_coherent_mem) {
+		if (buf->vaddr)
+			dma_vunmap_noncontiguous(buf->dev, buf->vaddr);
+		dma_free_noncontiguous(buf->dev, buf->size,
+				       buf->dma_sgt, buf->dma_dir);
+	} else {
+		if (buf->sgt_base) {
+			sg_free_table(buf->sgt_base);
+			kfree(buf->sgt_base);
+		}
+		dma_free_attrs(buf->dev, buf->size, buf->cookie,
+			       buf->dma_addr, buf->attrs);
 	}
-	dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr,
-		       buf->attrs);
 	put_device(buf->dev);
 	kfree(buf);
 }
 
+static int vb2_dc_alloc_coherent(struct vb2_dc_buf *buf)
+{
+	struct vb2_queue *q = buf->vb->vb2_queue;
+
+	buf->cookie = dma_alloc_attrs(buf->dev,
+				      buf->size,
+				      &buf->dma_addr,
+				      GFP_KERNEL | q->gfp_flags,
+				      buf->attrs);
+	if (!buf->cookie)
+		return -ENOMEM;
+
+	if (q->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
+		return 0;
+
+	buf->vaddr = buf->cookie;
+	return 0;
+}
+
+static int vb2_dc_alloc_non_coherent(struct vb2_dc_buf *buf)
+{
+	struct vb2_queue *q = buf->vb->vb2_queue;
+
+	buf->dma_sgt = dma_alloc_noncontiguous(buf->dev,
+					       buf->size,
+					       buf->dma_dir,
+					       GFP_KERNEL | q->gfp_flags,
+					       buf->attrs);
+	if (!buf->dma_sgt)
+		return -ENOMEM;
+
+	buf->dma_addr = sg_dma_address(buf->dma_sgt->sgl);
+
+	/*
+	 * For non-coherent buffers the kernel mapping is created on demand
+	 * in vb2_dc_vaddr().
+	 */
+	return 0;
+}
+
 static void *vb2_dc_alloc(struct vb2_buffer *vb,
 			  struct device *dev,
 			  unsigned long size)
 {
 	struct vb2_dc_buf *buf;
+	int ret;
 
 	if (WARN_ON(!dev))
 		return ERR_PTR(-EINVAL);
@@ -159,27 +243,28 @@ static void *vb2_dc_alloc(struct vb2_buffer *vb,
 		return ERR_PTR(-ENOMEM);
 
 	buf->attrs = vb->vb2_queue->dma_attrs;
-	buf->cookie = dma_alloc_attrs(dev, size, &buf->dma_addr,
-				      GFP_KERNEL | vb->vb2_queue->gfp_flags,
-				      buf->attrs);
-	if (!buf->cookie) {
-		dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
-		kfree(buf);
-		return ERR_PTR(-ENOMEM);
-	}
-
-	if ((buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0)
-		buf->vaddr = buf->cookie;
+	buf->dma_dir = vb->vb2_queue->dma_dir;
+	buf->vb = vb;
+	buf->non_coherent_mem = vb->vb2_queue->non_coherent_mem;
 
+	buf->size = size;
 	/* Prevent the device from being released while the buffer is used */
 	buf->dev = get_device(dev);
-	buf->size = size;
-	buf->dma_dir = vb->vb2_queue->dma_dir;
+
+	if (buf->non_coherent_mem)
+		ret = vb2_dc_alloc_non_coherent(buf);
+	else
+		ret = vb2_dc_alloc_coherent(buf);
+
+	if (ret) {
+		dev_err(dev, "dma alloc of size %ld failed\n", size);
+		kfree(buf);
+		return ERR_PTR(-ENOMEM);
+	}
 
 	buf->handler.refcount = &buf->refcount;
 	buf->handler.put = vb2_dc_put;
 	buf->handler.arg = buf;
-	buf->vb = vb;
 
 	refcount_set(&buf->refcount, 1);
 
@@ -196,9 +281,12 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 		return -EINVAL;
 	}
 
-	ret = dma_mmap_attrs(buf->dev, vma, buf->cookie,
-		buf->dma_addr, buf->size, buf->attrs);
-
+	if (buf->non_coherent_mem)
+		ret = dma_mmap_noncontiguous(buf->dev, vma, buf->size,
+					     buf->dma_sgt);
+	else
+		ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, buf->dma_addr,
+				     buf->size, buf->attrs);
 	if (ret) {
 		pr_err("Remapping memory failed, error: %d\n", ret);
 		return ret;
@@ -360,9 +448,15 @@ vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
 
 static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map)
 {
-	struct vb2_dc_buf *buf = dbuf->priv;
+	struct vb2_dc_buf *buf;
+	void *vaddr;
 
-	dma_buf_map_set_vaddr(map, buf->vaddr);
+	buf = dbuf->priv;
+	vaddr = vb2_dc_vaddr(buf->vb, buf);
+	if (!vaddr)
+		return -EINVAL;
+
+	dma_buf_map_set_vaddr(map, vaddr);
 
 	return 0;
 }
@@ -390,6 +484,9 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
 	int ret;
 	struct sg_table *sgt;
 
+	if (buf->non_coherent_mem)
+		return buf->dma_sgt;
+
 	sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
 	if (!sgt) {
 		dev_err(buf->dev, "failed to alloc sg table\n");
@@ -567,6 +664,8 @@ static void *vb2_dc_get_userptr(struct vb2_buffer *vb, struct device *dev,
 
 	buf->dma_addr = sg_dma_address(sgt->sgl);
 	buf->dma_sgt = sgt;
+	buf->non_coherent_mem = 1;
+
 out:
 	buf->size = size;
 
-- 
2.33.0.153.gba50c8fa24-goog

Re: [PATCHv6 0/8] videobuf2: support new noncontiguous DMA API

[Tomasz Figa]

Hi Sergey,

On Thu, Sep 9, 2021 at 8:24 PM Sergey Senozhatsky
<senozhatsky@chromium.org> wrote:
>
> Hello,
>
>         The series adds support for noncontiguous DMA API and
> V4L2_MEMORY_FLAG_NON_COHERENT UAPI.
>
> v5:
>
> https://lore.kernel.org/lkml/20210823122235.116189-1-senozhatsky@chromium.org/
>
> -- addressed feedback (Tomasz)
> -- reworked prepare/finish functions (Tomasz)
>
> Sergey Senozhatsky (8):
>   videobuf2: rework vb2_mem_ops API
>   videobuf2: inverse buffer cache_hints flags
>   videobuf2: split buffer cache_hints initialisation
>   videobuf2: move cache_hints handling to allocators
>   videobuf2: add V4L2_MEMORY_FLAG_NON_COHERENT flag
>   videobuf2: add queue memory coherency parameter
>   videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag
>   videobuf2: handle non-contiguous DMA allocations
>
>  .../userspace-api/media/v4l/buffer.rst        |  40 +++-
>  .../media/v4l/vidioc-create-bufs.rst          |   7 +-
>  .../media/v4l/vidioc-reqbufs.rst              |  16 +-
>  .../media/common/videobuf2/videobuf2-core.c   | 126 +++++++----
>  .../common/videobuf2/videobuf2-dma-contig.c   | 195 ++++++++++++++----
>  .../media/common/videobuf2/videobuf2-dma-sg.c |  39 ++--
>  .../media/common/videobuf2/videobuf2-v4l2.c   |  59 +++---
>  .../common/videobuf2/videobuf2-vmalloc.c      |  30 +--
>  drivers/media/dvb-core/dvb_vb2.c              |   2 +-
>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |   9 +-
>  drivers/media/v4l2-core/v4l2-ioctl.c          |   4 +-
>  include/media/videobuf2-core.h                |  59 +++---
>  include/uapi/linux/videodev2.h                |  11 +-
>  13 files changed, 411 insertions(+), 186 deletions(-)

Thanks a lot for working on this. This version looks good to me.

Acked-by: Tomasz Figa <tfiga@chromium.org>

Best regards,
Tomasz

Re: [PATCHv6 7/8] videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag

[Sergey Senozhatsky]

On (21/09/09 20:24), Sergey Senozhatsky wrote:
[..]
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 9b7032abb2c7..f118fe7a9f58 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -959,7 +959,8 @@ struct v4l2_requestbuffers {
>  	__u32			type;		/* enum v4l2_buf_type */
>  	__u32			memory;		/* enum v4l2_memory */
>  	__u32			capabilities;
> -	__u32			reserved[1];
> +	__u8			flags;
> +	__u8			reserved[3];
>  };

[..]

>  struct v4l2_create_buffers {
> @@ -2515,7 +2519,8 @@ struct v4l2_create_buffers {
>  	__u32			memory;
>  	struct v4l2_format	format;
>  	__u32			capabilities;
> -	__u32			reserved[7];
> +	__u32			flags;
> +	__u32			reserved[6];
>  };

These UAPI changes break strace compilation (older versions). Up until
Feb 2021 strace had compile time asserts that check-ed sizeof() ->reserved
fields.

  static_assert failed due to requirement
   '(sizeof (((struct v4l2_create_buffers *)0)->reserved)) >= (sizeof (((struct_v4l2_create_buffers *)0)->reserved))'
   "Unexpected struct v4l2_create_buffers.reserved size, please update the decoder"

It seems that strace has dropped those assertions

https://github.com/strace/strace/commit/e5554291d14b852f61385ba5ba59412d133ac99d#diff-d534423e8a79b6957ef4deb7f8bbd3276bf18ede6a82553e8823ee4f840b6e06


But we, probably, need to use unions in UAPI. Any thoughts?

Re: [PATCHv6 2/8] videobuf2: inverse buffer cache_hints flags

[Chen-Yu Tsai]

Hi,

On Thu, Sep 09, 2021 at 08:24:24PM +0900, Sergey Senozhatsky wrote:
> It would be less error prone if the default cache hints value
> (we kzalloc() structs, so it's zeroed out by default) would be
> to "always sync/flush" caches. Inverse and rename cache hints
> flags.
> 
> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> ---
>  .../media/common/videobuf2/videobuf2-core.c   | 31 ++++++-------------
>  .../media/common/videobuf2/videobuf2-v4l2.c   | 17 +++-------
>  include/media/videobuf2-core.h                | 12 +++----
>  3 files changed, 21 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index c4ff356da600..9d57df348b5f 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c

[...]

> @@ -415,17 +415,6 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
>  		vb->index = q->num_buffers + buffer;
>  		vb->type = q->type;
>  		vb->memory = memory;
> -		/*
> -		 * We need to set these flags here so that the videobuf2 core
> -		 * will call ->prepare()/->finish() cache sync/flush on vb2
> -		 * buffers when appropriate. However, we can avoid explicit
> -		 * ->prepare() and ->finish() cache sync for DMABUF buffers,
> -		 * because DMA exporter takes care of it.
> -		 */
> -		if (q->memory != VB2_MEMORY_DMABUF) {
> -			vb->need_cache_sync_on_prepare = 1;
> -			vb->need_cache_sync_on_finish = 1;
> -		}

This hunk seems odd. It's not inverting the logic but just removing
the block wholesale. The end result is different. This seems to be fixed
in a following patch, but the change here doesn't match what the commit
log says.

ChenYu