From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from perceval.ideasonboard.com ([95.142.166.194]:41406 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750881Ab2JGNhc (ORCPT ); Sun, 7 Oct 2012 09:37:32 -0400 From: Laurent Pinchart To: Tomasz Stanislawski Cc: linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, airlied@redhat.com, m.szyprowski@samsung.com, kyungmin.park@samsung.com, sumit.semwal@ti.com, daeinki@gmail.com, daniel.vetter@ffwll.ch, robdclark@gmail.com, pawel@osciak.com, linaro-mm-sig@lists.linaro.org, hverkuil@xs4all.nl, remi@remlab.net, subashrp@gmail.com, mchehab@redhat.com, zhangfei.gao@gmail.com, s.nawrocki@samsung.com, k.debski@samsung.com Subject: Re: [PATCHv9 20/25] v4l: vb2-dma-contig: add support for DMABUF exporting Date: Sun, 07 Oct 2012 15:38:13 +0200 Message-ID: <7677813.CEvbgaK590@avalon> In-Reply-To: <1349188056-4886-21-git-send-email-t.stanislaws@samsung.com> References: <1349188056-4886-1-git-send-email-t.stanislaws@samsung.com> <1349188056-4886-21-git-send-email-t.stanislaws@samsung.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org List-ID: Hi Tomasz, Thanks for the patch. On Tuesday 02 October 2012 16:27:31 Tomasz Stanislawski wrote: > This patch adds support for exporting a dma-contig buffer using > DMABUF interface. > > Signed-off-by: Tomasz Stanislawski > Signed-off-by: Kyungmin Park Acked-by: Laurent Pinchart > --- > drivers/media/video/videobuf2-dma-contig.c | 200 +++++++++++++++++++++++++ > 1 file changed, 200 insertions(+) > > diff --git a/drivers/media/video/videobuf2-dma-contig.c > b/drivers/media/video/videobuf2-dma-contig.c index 0e065ce..b138b5c 100644 > --- a/drivers/media/video/videobuf2-dma-contig.c > +++ b/drivers/media/video/videobuf2-dma-contig.c > @@ -36,6 +36,7 @@ struct vb2_dc_buf { > /* MMAP related */ > struct vb2_vmarea_handler handler; > atomic_t refcount; > + struct sg_table *sgt_base; > > /* USERPTR related */ > struct vm_area_struct *vma; > @@ -142,6 +143,10 @@ static void vb2_dc_put(void *buf_priv) > if (!atomic_dec_and_test(&buf->refcount)) > return; > > + if (buf->sgt_base) { > + sg_free_table(buf->sgt_base); > + kfree(buf->sgt_base); > + } > dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr); > kfree(buf); > } > @@ -213,6 +218,200 @@ static int vb2_dc_mmap(void *buf_priv, struct > vm_area_struct *vma) } > > /*********************************************/ > +/* DMABUF ops for exporters */ > +/*********************************************/ > + > +struct vb2_dc_attachment { > + struct sg_table sgt; > + enum dma_data_direction dir; > +}; > + > +static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device > *dev, + struct dma_buf_attachment *dbuf_attach) > +{ > + struct vb2_dc_attachment *attach; > + unsigned int i; > + struct scatterlist *rd, *wr; > + struct sg_table *sgt; > + struct vb2_dc_buf *buf = dbuf->priv; > + int ret; > + > + attach = kzalloc(sizeof(*attach), GFP_KERNEL); > + if (!attach) > + return -ENOMEM; > + > + sgt = &attach->sgt; > + /* Copy the buf->base_sgt scatter list to the attachment, as we can't > + * map the same scatter list to multiple attachments at the same time. > + */ > + ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL); > + if (ret) { > + kfree(attach); > + return -ENOMEM; > + } > + > + rd = buf->sgt_base->sgl; > + wr = sgt->sgl; > + for (i = 0; i < sgt->orig_nents; ++i) { > + sg_set_page(wr, sg_page(rd), rd->length, rd->offset); > + rd = sg_next(rd); > + wr = sg_next(wr); > + } > + > + attach->dir = DMA_NONE; > + dbuf_attach->priv = attach; > + > + return 0; > +} > + > +static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf, > + struct dma_buf_attachment *db_attach) > +{ > + struct vb2_dc_attachment *attach = db_attach->priv; > + struct sg_table *sgt; > + > + if (!attach) > + return; > + > + sgt = &attach->sgt; > + > + /* release the scatterlist cache */ > + if (attach->dir != DMA_NONE) > + dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, > + attach->dir); > + sg_free_table(sgt); > + kfree(attach); > + db_attach->priv = NULL; > +} > + > +static struct sg_table *vb2_dc_dmabuf_ops_map( > + struct dma_buf_attachment *db_attach, enum dma_data_direction dir) > +{ > + struct vb2_dc_attachment *attach = db_attach->priv; > + /* stealing dmabuf mutex to serialize map/unmap operations */ > + struct mutex *lock = &db_attach->dmabuf->lock; > + struct sg_table *sgt; > + int ret; > + > + mutex_lock(lock); > + > + sgt = &attach->sgt; > + /* return previously mapped sg table */ > + if (attach->dir == dir) { > + mutex_unlock(lock); > + return sgt; > + } > + > + /* release any previous cache */ > + if (attach->dir != DMA_NONE) { > + dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, > + attach->dir); > + attach->dir = DMA_NONE; > + } > + > + /* mapping to the client with new direction */ > + ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dir); > + if (ret <= 0) { > + pr_err("failed to map scatterlist\n"); > + mutex_unlock(lock); > + return ERR_PTR(-EIO); > + } > + > + attach->dir = dir; > + > + mutex_unlock(lock); > + > + return sgt; > +} > + > +static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, > + struct sg_table *sgt, enum dma_data_direction dir) > +{ > + /* nothing to be done here */ > +} > + > +static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf) > +{ > + /* drop reference obtained in vb2_dc_get_dmabuf */ > + vb2_dc_put(dbuf->priv); > +} > + > +static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long > pgnum) +{ > + struct vb2_dc_buf *buf = dbuf->priv; > + > + return buf->vaddr + pgnum * PAGE_SIZE; > +} > + > +static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf) > +{ > + struct vb2_dc_buf *buf = dbuf->priv; > + > + return buf->vaddr; > +} > + > +static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf, > + struct vm_area_struct *vma) > +{ > + return vb2_dc_mmap(dbuf->priv, vma); > +} > + > +static struct dma_buf_ops vb2_dc_dmabuf_ops = { > + .attach = vb2_dc_dmabuf_ops_attach, > + .detach = vb2_dc_dmabuf_ops_detach, > + .map_dma_buf = vb2_dc_dmabuf_ops_map, > + .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap, > + .kmap = vb2_dc_dmabuf_ops_kmap, > + .kmap_atomic = vb2_dc_dmabuf_ops_kmap, > + .vmap = vb2_dc_dmabuf_ops_vmap, > + .mmap = vb2_dc_dmabuf_ops_mmap, > + .release = vb2_dc_dmabuf_ops_release, > +}; > + > +static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf) > +{ > + int ret; > + struct sg_table *sgt; > + > + sgt = kmalloc(sizeof(*sgt), GFP_KERNEL); > + if (!sgt) { > + dev_err(buf->dev, "failed to alloc sg table\n"); > + return NULL; > + } > + > + ret = dma_get_sgtable(buf->dev, sgt, buf->vaddr, buf->dma_addr, > + buf->size); > + if (ret < 0) { > + dev_err(buf->dev, "failed to get scatterlist from DMA API\n"); > + kfree(sgt); > + return NULL; > + } > + > + return sgt; > +} > + > +static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv) > +{ > + struct vb2_dc_buf *buf = buf_priv; > + struct dma_buf *dbuf; > + > + if (!buf->sgt_base) > + buf->sgt_base = vb2_dc_get_base_sgt(buf); > + > + if (WARN_ON(!buf->sgt_base)) > + return NULL; > + > + dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, 0); > + if (IS_ERR(dbuf)) > + return NULL; > + > + /* dmabuf keeps reference to vb2 buffer */ > + atomic_inc(&buf->refcount); > + > + return dbuf; > +} > + > +/*********************************************/ > /* callbacks for USERPTR buffers */ > /*********************************************/ > > @@ -519,6 +718,7 @@ static void *vb2_dc_attach_dmabuf(void *alloc_ctx, > struct dma_buf *dbuf, const struct vb2_mem_ops vb2_dma_contig_memops = { > .alloc = vb2_dc_alloc, > .put = vb2_dc_put, > + .get_dmabuf = vb2_dc_get_dmabuf, > .cookie = vb2_dc_cookie, > .vaddr = vb2_dc_vaddr, > .mmap = vb2_dc_mmap, -- Regards, Laurent Pinchart