Hi Sakari,
Thank you for the patch.
On Friday 11 Sep 2015 14:50:33 Sakari Ailus wrote:
> The desirable DMA attributes are not generic for all devices using
> Videobuf2 contiguous DMA ops. Let the drivers decide.
>
> This change also results in MMAP buffers always having an sg_table
> (dma_sgt field).
>
> Also arrange the header files alphabetically.
>
> 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.
>
> The driver API changes were done using the following coccinelle spatch:
>
> @@
> expression E;
> @@
>
> - vb2_dma_contig_init_ctx(E)
> + vb2_dma_contig_init_ctx(E, NULL)
I wanted to mention that this patch includes no driver change, but the
vb2_dma_contig_init_ctx() has disappeared now, replaced by an attrs attribute
to the .alloc() operation. This, and the fact that the kernel has moved from
struct dma_attrs to unsigned long to store the DMA attributes, generates a lot
of conflicts. I'll review the rebased version.
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> ---
> drivers/media/v4l2-core/videobuf2-dma-contig.c | 104 +++++++++++++++-------
> include/media/videobuf2-dma-contig.h | 3 +-
> 2 files changed, 79 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 65bc687..65ee122
> 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> @@ -11,11 +11,11 @@
> */
>
> #include <linux/dma-buf.h>
> +#include <linux/dma-mapping.h>
> #include <linux/module.h>
> #include <linux/scatterlist.h>
> #include <linux/sched.h>
> #include <linux/slab.h>
> -#include <linux/dma-mapping.h>
>
> #include <media/videobuf2-core.h>
> #include <media/videobuf2-dma-contig.h>
> @@ -23,6 +23,7 @@
>
> struct vb2_dc_conf {
> struct device *dev;
> + struct dma_attrs attrs;
> };
>
> struct vb2_dc_buf {
> @@ -34,6 +35,7 @@ struct vb2_dc_buf {
> struct sg_table *dma_sgt;
>
> /* MMAP related */
> + struct dma_attrs *attrs;
> struct vb2_vmarea_handler handler;
> atomic_t refcount;
>
> @@ -135,8 +137,12 @@ static void vb2_dc_prepare(void *buf_priv)
> struct vb2_dc_buf *buf = buf_priv;
> struct sg_table *sgt = buf->dma_sgt;
>
> - /* DMABUF exporter will flush the cache for us */
> - if (!buf->vma)
> + /*
> + * DMABUF exporter will flush the cache for us; only USERPTR
> + * and MMAP buffers with non-coherent memory will be flushed.
> + */
> + if (!buf->attrs ||
> + !dma_get_attr(DMA_ATTR_NON_CONSISTENT, buf->attrs))
> return;
>
> dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
> @@ -147,8 +153,12 @@ static void vb2_dc_finish(void *buf_priv)
> struct vb2_dc_buf *buf = buf_priv;
> struct sg_table *sgt = buf->dma_sgt;
>
> - /* DMABUF exporter will flush the cache for us */
> - if (!buf->vma)
> + /*
> + * DMABUF exporter will flush the cache for us; only USERPTR
> + * and MMAP buffers with non-coherent memory will be flushed.
> + */
> + if (!buf->attrs ||
> + !dma_get_attr(DMA_ATTR_NON_CONSISTENT, buf->attrs))
> return;
>
> dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
> @@ -169,7 +179,8 @@ static void vb2_dc_put(void *buf_priv)
> sg_free_table(buf->dma_sgt);
> kfree(buf->dma_sgt);
> }
> - dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
> + dma_free_attrs(buf->dev, buf->size, buf->vaddr, buf->dma_addr,
> + buf->attrs);
> put_device(buf->dev);
> kfree(buf);
> }
> @@ -185,14 +196,25 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned
> long size, if (!buf)
> return ERR_PTR(-ENOMEM);
>
> - buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr,
> - GFP_KERNEL | gfp_flags);
> + buf->attrs = &conf->attrs;
> +
> + buf->vaddr = dma_alloc_attrs(dev, size, &buf->dma_addr,
> + GFP_KERNEL | gfp_flags, buf->attrs);
> if (!buf->vaddr) {
> - dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
> + dev_err(dev, "dma_alloc_attrs of size %ld failed\n", size);
> kfree(buf);
> return ERR_PTR(-ENOMEM);
> }
>
> + if (dma_get_attr(DMA_ATTR_NON_CONSISTENT, buf->attrs)) {
> + buf->dma_sgt = vb2_dc_get_base_sgt(buf);
> + if (!buf->dma_sgt) {
> + dma_free_attrs(dev, size, buf->vaddr, buf->dma_addr,
> + buf->attrs);
> + return ERR_PTR(-ENOMEM);
> + }
> + }
> +
> /* Prevent the device from being released while the buffer is used */
> buf->dev = get_device(dev);
> buf->size = size;
> @@ -223,8 +245,8 @@ static int vb2_dc_mmap(void *buf_priv, struct
> vm_area_struct *vma) */
> vma->vm_pgoff = 0;
>
> - ret = dma_mmap_coherent(buf->dev, vma, buf->vaddr,
> - buf->dma_addr, buf->size);
> + ret = dma_mmap_attrs(buf->dev, vma, buf->vaddr, buf->dma_addr,
> + buf->size, buf->attrs);
>
> if (ret) {
> pr_err("Remapping memory failed, error: %d\n", ret);
> @@ -370,6 +392,34 @@ static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf
> *dbuf, unsigned long pgnum) return buf->vaddr + pgnum * PAGE_SIZE;
> }
>
> +static int vb2_dc_dmabuf_ops_begin_cpu_access(
> + struct dma_buf *dbuf, size_t start, size_t len,
> + enum dma_data_direction direction)
> +{
> + struct vb2_dc_buf *buf = dbuf->priv;
> + struct sg_table *sgt = buf->dma_sgt;
> +
> + if (!dma_get_attr(DMA_ATTR_NON_CONSISTENT, buf->attrs))
> + return 0;
> +
> + dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
> +
> + return 0;
> +}
> +
> +static void vb2_dc_dmabuf_ops_end_cpu_access(
> + struct dma_buf *dbuf, size_t start, size_t len,
> + enum dma_data_direction direction)
> +{
> + struct vb2_dc_buf *buf = dbuf->priv;
> + struct sg_table *sgt = buf->dma_sgt;
> +
> + if (!dma_get_attr(DMA_ATTR_NON_CONSISTENT, buf->attrs))
> + return;
> +
> + dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
> +}
> +
> static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf)
> {
> struct vb2_dc_buf *buf = dbuf->priv;
> @@ -390,6 +440,8 @@ static struct dma_buf_ops vb2_dc_dmabuf_ops = {
> .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
> .kmap = vb2_dc_dmabuf_ops_kmap,
> .kmap_atomic = vb2_dc_dmabuf_ops_kmap,
> + .begin_cpu_access = vb2_dc_dmabuf_ops_begin_cpu_access,
> + .end_cpu_access = vb2_dc_dmabuf_ops_end_cpu_access,
> .vmap = vb2_dc_dmabuf_ops_vmap,
> .mmap = vb2_dc_dmabuf_ops_mmap,
> .release = vb2_dc_dmabuf_ops_release,
> @@ -514,15 +566,13 @@ static void vb2_dc_put_userptr(void *buf_priv)
> struct sg_table *sgt = buf->dma_sgt;
>
> if (sgt) {
> - DEFINE_DMA_ATTRS(attrs);
> -
> - dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
> /*
> - * No need to sync to CPU, it's already synced to the CPU
> - * since the finish() memop will have been called before this.
> + * Don't ask to skip cache sync in case if the user
> + * did ask to skip cache flush the last time the
> + * buffer was dequeued.
> */
> dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
> - buf->dma_dir, &attrs);
> + buf->dma_dir, buf->attrs);
> if (!vma_is_io(buf->vma))
> vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
>
> @@ -579,9 +629,6 @@ static void *vb2_dc_get_userptr(void *alloc_ctx,
> unsigned long vaddr, struct sg_table *sgt;
> unsigned long contig_size;
> unsigned long dma_align = dma_get_cache_alignment();
> - DEFINE_DMA_ATTRS(attrs);
> -
> - dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
>
> /* Only cache aligned DMA transfers are reliable */
> if (!IS_ALIGNED(vaddr | size, dma_align)) {
> @@ -598,6 +645,8 @@ static void *vb2_dc_get_userptr(void *alloc_ctx,
> unsigned long vaddr, if (!buf)
> return ERR_PTR(-ENOMEM);
>
> + buf->attrs = &conf->attrs;
> +
> buf->dev = conf->dev;
> buf->dma_dir = dma_dir;
>
> @@ -667,12 +716,8 @@ static void *vb2_dc_get_userptr(void *alloc_ctx,
> unsigned long vaddr, kfree(pages);
> pages = NULL;
>
> - /*
> - * No need to sync to the device, this will happen later when the
> - * prepare() memop is called.
> - */
> sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
> - buf->dma_dir, &attrs);
> + buf->dma_dir, buf->attrs);
> if (sgt->nents <= 0) {
> pr_err("failed to map scatterlist\n");
> ret = -EIO;
> @@ -695,7 +740,7 @@ static void *vb2_dc_get_userptr(void *alloc_ctx,
> unsigned long vaddr,
>
> fail_map_sg:
> dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
> - buf->dma_dir, &attrs);
> + buf->dma_dir, buf->attrs);
>
> fail_sgt_init:
> if (!vma_is_io(buf->vma))
> @@ -856,7 +901,7 @@ const struct vb2_mem_ops vb2_dma_contig_memops = {
> };
> EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
>
> -void *vb2_dma_contig_init_ctx(struct device *dev)
> +void *vb2_dma_contig_init_ctx(struct device *dev, struct dma_attrs *attrs)
> {
> struct vb2_dc_conf *conf;
>
> @@ -866,6 +911,11 @@ void *vb2_dma_contig_init_ctx(struct device *dev)
>
> conf->dev = dev;
>
> + if (!attrs)
> + init_dma_attrs(&conf->attrs);
> + else
> + conf->attrs = *attrs;
> +
> return conf;
> }
> EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);
> diff --git a/include/media/videobuf2-dma-contig.h
> b/include/media/videobuf2-dma-contig.h index 8197f87..1b85282 100644
> --- a/include/media/videobuf2-dma-contig.h
> +++ b/include/media/videobuf2-dma-contig.h
> @@ -24,7 +24,8 @@ vb2_dma_contig_plane_dma_addr(struct vb2_buffer *vb,
> unsigned int plane_no) return *addr;
> }
>
> -void *vb2_dma_contig_init_ctx(struct device *dev);
> +void *vb2_dma_contig_init_ctx(struct device *dev,
> + struct dma_attrs *attrs);
> void vb2_dma_contig_cleanup_ctx(void *alloc_ctx);
>
> extern const struct vb2_mem_ops vb2_dma_contig_memops;
--
Regards,
Laurent Pinchart
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