This patch adds description and usage examples for importing DMABUF file descriptor in V4L2.

Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com CC: linux-doc@vger.kernel.org --- Documentation/DocBook/media/v4l/compat.xml | 4 + Documentation/DocBook/media/v4l/io.xml | 179 ++++++++++++++++++++ .../DocBook/media/v4l/vidioc-create-bufs.xml | 1 + Documentation/DocBook/media/v4l/vidioc-qbuf.xml | 15 ++ Documentation/DocBook/media/v4l/vidioc-reqbufs.xml | 45 ++--- 5 files changed, 223 insertions(+), 21 deletions(-)

diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml index ea42ef8..07a311f 100644 --- a/Documentation/DocBook/media/v4l/compat.xml +++ b/Documentation/DocBook/media/v4l/compat.xml @@ -2587,6 +2587,10 @@ ioctls.</para> <para><link linkend="v4l2-auto-focus-area"><constant> V4L2_CID_AUTO_FOCUS_AREA</constant></link> control.</para> </listitem> + <listitem> + <para>Importing DMABUF file descriptors as a new IO method described + in <xref linkend="dmabuf" />.</para> + </listitem> </itemizedlist> </section>

diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index fd6aca2..521f699 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -472,6 +472,162 @@ rest should be evident.</para> </footnote></para> </section>

+ <section id="dmabuf"> + <title>Streaming I/O (DMA buffer importing)</title> + + <note> + <title>Experimental</title> + <para>This is an <link linkend="experimental"> experimental </link> + interface and may change in the future.</para> + </note> + +<para>The DMABUF framework provides a generic mean for sharing buffers between + multiple devices. Device drivers that support DMABUF can export a DMA buffer +to userspace as a file descriptor (known as the exporter role), import a DMA +buffer from userspace using a file descriptor previously exported for a +different or the same device (known as the importer role), or both. This +section describes the DMABUF importer role API in V4L2.</para> + +<para>Input and output devices support the streaming I/O method when the +<constant>V4L2_CAP_STREAMING</constant> flag in the +<structfield>capabilities</structfield> field of &v4l2-capability; returned by +the &VIDIOC-QUERYCAP; ioctl is set. Whether importing DMA buffers through +DMABUF file descriptors is supported is determined by calling the +&VIDIOC-REQBUFS; ioctl with the memory type set to +<constant>V4L2_MEMORY_DMABUF</constant>.</para> + + <para>This I/O method is dedicated for sharing DMA buffers between V4L and +other APIs. Buffers (planes) are allocated by a driver on behalf of the +application, and exported to the application as file descriptors using an API +specific to the allocator driver. Only those file descriptor are exchanged, +these files and meta-information are passed in &v4l2-buffer; (or in +&v4l2-plane; in the multi-planar API case). The driver must be switched into +DMABUF I/O mode by calling the &VIDIOC-REQBUFS; with the desired buffer type. +No buffers (planes) are allocated beforehand, consequently they are not indexed +and cannot be queried like mapped buffers with the +<constant>VIDIOC_QUERYBUF</constant> ioctl.</para> + + <example> + <title>Initiating streaming I/O with DMABUF file descriptors</title> + + <programlisting> +&v4l2-requestbuffers; reqbuf; + +memset (&amp;reqbuf, 0, sizeof (reqbuf)); +reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; +reqbuf.memory = V4L2_MEMORY_DMABUF; + +if (ioctl (fd, &VIDIOC-REQBUFS;, &amp;reqbuf) == -1) { + if (errno == EINVAL) + printf ("Video capturing or DMABUF streaming is not supported\n"); + else + perror ("VIDIOC_REQBUFS"); + + exit (EXIT_FAILURE); +} + </programlisting> + </example> + + <para>Buffer (plane) file is passed on the fly with the &VIDIOC-QBUF; +ioctl. In case of multiplanar buffers, every plane can be associated with a +different DMABUF descriptor.Although buffers are commonly cycled, applications +can pass different DMABUF descriptor at each <constant>VIDIOC_QBUF</constant> +call.</para> + + <example> + <title>Queueing DMABUF using single plane API</title> + + <programlisting> +int buffer_queue(int v4lfd, int index, int dmafd) +{ + &v4l2-buffer; buf; + + memset(&amp;buf, 0, sizeof buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; + buf.memory = V4L2_MEMORY_DMABUF; + buf.index = index; + buf.m.fd = dmafd; + + if (ioctl (v4lfd, &VIDIOC-QBUF;, &amp;buf) == -1) { + perror ("VIDIOC_QBUF"); + return -1; + } + + return 0; +} + </programlisting> + </example> + + <example> + <title>Queueing DMABUF using multi plane API</title> + + <programlisting> +int buffer_queue_mp(int v4lfd, int index, int dmafd[], int n_planes) +{ + &v4l2-buffer; buf; + &v4l2-plane; planes[VIDEO_MAX_PLANES]; + int i; + + memset(&amp;buf, 0, sizeof buf); + buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE; + buf.memory = V4L2_MEMORY_DMABUF; + buf.index = index; + buf.m.planes = planes; + buf.length = n_planes; + + memset(&amp;planes, 0, sizeof planes); + + for (i = 0; i &lt; n_planes; ++i) + buf.m.planes[i].m.fd = dmafd[i]; + + if (ioctl (v4lfd, &VIDIOC-QBUF;, &amp;buf) == -1) { + perror ("VIDIOC_QBUF"); + return -1; + } + + return 0; +} + </programlisting> + </example> + + <para>Filled or displayed buffers are dequeued with the +&VIDIOC-DQBUF; ioctl. The driver can unlock the buffer at any +time between the completion of the DMA and this ioctl. The memory is +also unlocked when &VIDIOC-STREAMOFF; is called, &VIDIOC-REQBUFS;, or +when the device is closed.</para> + + <para>For capturing applications it is customary to enqueue a +number of empty buffers, to start capturing and enter the read loop. +Here the application waits until a filled buffer can be dequeued, and +re-enqueues the buffer when the data is no longer needed. Output +applications fill and enqueue buffers, when enough buffers are stacked +up output is started. In the write loop, when the application +runs out of free buffers it must wait until an empty buffer can be +dequeued and reused. Two methods exist to suspend execution of the +application until one or more buffers can be dequeued. By default +<constant>VIDIOC_DQBUF</constant> blocks when no buffer is in the +outgoing queue. When the <constant>O_NONBLOCK</constant> flag was +given to the &func-open; function, <constant>VIDIOC_DQBUF</constant> +returns immediately with an &EAGAIN; when no buffer is available. The +&func-select; or &func-poll; function are always available.</para> + + <para>To start and stop capturing or output applications call the +&VIDIOC-STREAMON; and &VIDIOC-STREAMOFF; ioctls. Note that +<constant>VIDIOC_STREAMOFF</constant> removes all buffers from both queues and +unlocks all buffers as a side effect. Since there is no notion of doing +anything "now" on a multitasking system, if an application needs to synchronize +with another event it should examine the &v4l2-buffer; +<structfield>timestamp</structfield> of captured buffers, or set the field +before enqueuing buffers for output.</para> + + <para>Drivers implementing DMABUF importing I/O must support the +<constant>VIDIOC_REQBUFS</constant>, <constant>VIDIOC_QBUF</constant>, +<constant>VIDIOC_DQBUF</constant>, <constant>VIDIOC_STREAMON</constant> and +<constant>VIDIOC_STREAMOFF</constant> ioctl, the <function>select()</function> +and <function>poll()</function> function.</para> + + </section> + <section id="async"> <title>Asynchronous I/O</title>

@@ -673,6 +829,14 @@ memory, set by the application. See <xref linkend="userp" /> for details. <structname>v4l2_buffer</structname> structure.</entry> </row> <row> + <entry></entry> + <entry>int</entry> + <entry><structfield>fd</structfield></entry> + <entry>For the single-plane API and when +<structfield>memory</structfield> is <constant>V4L2_MEMORY_DMABUF</constant> this +is the file descriptor associated with a DMABUF buffer.</entry> + </row> + <row> <entry>__u32</entry> <entry><structfield>length</structfield></entry> <entry></entry> @@ -748,6 +912,15 @@ should set this to 0.</entry> </entry> </row> <row> + <entry></entry> + <entry>int</entry> + <entry><structfield>fd</structfield></entry> + <entry>When the memory type in the containing &v4l2-buffer; is + <constant>V4L2_MEMORY_DMABUF</constant>, this is a file + descriptor associated with a DMABUF buffer, similar to the + <structfield>fd</structfield> field in &v4l2-buffer;.</entry> + </row> + <row> <entry>__u32</entry> <entry><structfield>data_offset</structfield></entry> <entry></entry> @@ -982,6 +1155,12 @@ pointer</link> I/O.</entry> <entry>3</entry> <entry>[to do]</entry> </row> + <row> + <entry><constant>V4L2_MEMORY_DMABUF</constant></entry> + <entry>2</entry> + <entry>The buffer is used for <link linkend="dmabuf">DMA shared +buffer</link> I/O.</entry> + </row> </tbody> </tgroup> </table> diff --git a/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml index 765549f..fee66ac 100644 --- a/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml +++ b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml @@ -104,6 +104,7 @@ information.</para> <entry><structfield>memory</structfield></entry> <entry>Applications set this field to <constant>V4L2_MEMORY_MMAP</constant> or +<constant>V4L2_MEMORY_DMABUF</constant> or <constant>V4L2_MEMORY_USERPTR</constant>. See <xref linkend="v4l2-memory" /></entry> </row> diff --git a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml index 9caa49a..cb5f5ff 100644 --- a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml +++ b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml @@ -112,6 +112,21 @@ they cannot be swapped out to disk. Buffers remain locked until dequeued, until the &VIDIOC-STREAMOFF; or &VIDIOC-REQBUFS; ioctl is called, or until the device is closed.</para>

+ <para>To enqueue a <link linkend="dmabuf">DMABUF</link> buffer applications +set the <structfield>memory</structfield> field to +<constant>V4L2_MEMORY_DMABUF</constant> and the <structfield>m.fd</structfield> +to a file descriptor associated with a DMABUF buffer. When the multi-planar API is +used and <structfield>m.fd</structfield> of the passed array of &v4l2-plane; +have to be used instead. When <constant>VIDIOC_QBUF</constant> is called with a +pointer to this structure the driver sets the +<constant>V4L2_BUF_FLAG_QUEUED</constant> flag and clears the +<constant>V4L2_BUF_FLAG_MAPPED</constant> and +<constant>V4L2_BUF_FLAG_DONE</constant> flags in the +<structfield>flags</structfield> field, or it returns an error code. This +ioctl locks the buffer. Buffers remain locked until dequeued, +until the &VIDIOC-STREAMOFF; or &VIDIOC-REQBUFS; ioctl is called, or until the +device is closed.</para> + <para>Applications call the <constant>VIDIOC_DQBUF</constant> ioctl to dequeue a filled (capturing) or displayed (output) buffer from the driver's outgoing queue. They just set the diff --git a/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml index d7c9505..13381ea 100644 --- a/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml +++ b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml @@ -48,28 +48,30 @@ <refsect1> <title>Description</title>

- <para>This ioctl is used to initiate <link linkend="mmap">memory -mapped</link> or <link linkend="userp">user pointer</link> -I/O. Memory mapped buffers are located in device memory and must be -allocated with this ioctl before they can be mapped into the -application's address space. User buffers are allocated by -applications themselves, and this ioctl is merely used to switch the -driver into user pointer I/O mode and to setup some internal structures.</para> +<para>This ioctl is used to initiate <link linkend="mmap">memory mapped</link>, +<link linkend="userp">user pointer</link> or <link +linkend="dmabuf">DMABUF</link> based I/O. Memory mapped buffers are located in +device memory and must be allocated with this ioctl before they can be mapped +into the application's address space. User buffers are allocated by +applications themselves, and this ioctl is merely used to switch the driver +into user pointer I/O mode and to setup some internal structures. +Similarly, DMABUF buffers are allocated by applications through a device +driver, and this ioctl only configures the driver into DMABUF I/O mode without +performing any direct allocation.</para>

- <para>To allocate device buffers applications initialize all -fields of the <structname>v4l2_requestbuffers</structname> structure. -They set the <structfield>type</structfield> field to the respective -stream or buffer type, the <structfield>count</structfield> field to -the desired number of buffers, <structfield>memory</structfield> -must be set to the requested I/O method and the <structfield>reserved</structfield> array -must be zeroed. When the ioctl -is called with a pointer to this structure the driver will attempt to allocate -the requested number of buffers and it stores the actual number -allocated in the <structfield>count</structfield> field. It can be -smaller than the number requested, even zero, when the driver runs out -of free memory. A larger number is also possible when the driver requires -more buffers to function correctly. For example video output requires at least two buffers, -one displayed and one filled by the application.</para> + <para>To allocate device buffers applications initialize all fields of the +<structname>v4l2_requestbuffers</structname> structure. They set the +<structfield>type</structfield> field to the respective stream or buffer type, +the <structfield>count</structfield> field to the desired number of buffers, +<structfield>memory</structfield> must be set to the requested I/O method and +the <structfield>reserved</structfield> array must be zeroed. When the ioctl is +called with a pointer to this structure the driver will attempt to allocate the +requested number of buffers and it stores the actual number allocated in the +<structfield>count</structfield> field. It can be smaller than the number +requested, even zero, when the driver runs out of free memory. A larger number +is also possible when the driver requires more buffers to function correctly. +For example video output requires at least two buffers, one displayed and one +filled by the application.</para> <para>When the I/O method is not supported the ioctl returns an &EINVAL;.</para>

@@ -103,6 +105,7 @@ as the &v4l2-format; <structfield>type</structfield> field. See <xref <entry><structfield>memory</structfield></entry> <entry>Applications set this field to <constant>V4L2_MEMORY_MMAP</constant> or +<constant>V4L2_MEMORY_DMABUF</constant> or <constant>V4L2_MEMORY_USERPTR</constant>. See <xref linkend="v4l2-memory" />.</entry> </row>

From: Sumit Semwal sumit.semwal@ti.com

Adding DMABUF memory type causes videobuf to complain about not using it in some switch cases. This patch removes these warnings.

Signed-off-by: Sumit Semwal sumit.semwal@ti.com Acked-by: Laurent Pinchart laurent.pinchart@ideasonboard.com --- drivers/media/video/videobuf-core.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/drivers/media/video/videobuf-core.c b/drivers/media/video/videobuf-core.c index ffdf59c..3e3e55f 100644 --- a/drivers/media/video/videobuf-core.c +++ b/drivers/media/video/videobuf-core.c @@ -335,6 +335,9 @@ static void videobuf_status(struct videobuf_queue *q, struct v4l2_buffer *b, case V4L2_MEMORY_OVERLAY: b->m.offset = vb->boff; break; + case V4L2_MEMORY_DMABUF: + /* DMABUF is not handled in videobuf framework */ + break; }

b->flags = 0; @@ -411,6 +414,7 @@ int __videobuf_mmap_setup(struct videobuf_queue *q, break; case V4L2_MEMORY_USERPTR: case V4L2_MEMORY_OVERLAY: + case V4L2_MEMORY_DMABUF: /* nothing */ break; }

vb2-dma-contig returns a vb2_dc_conf structure instance as the vb2 allocation context. That structure only stores a pointer to the physical device. Remove it and use the device pointer directly as the allocation context.

Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com Acked-by: Laurent Pinchart laurent.pinchart@ideasonboard.com --- drivers/media/video/videobuf2-dma-contig.c | 29 +++++++--------------------- 1 file changed, 7 insertions(+), 22 deletions(-)

diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c index a05784f..a019cd1 100644 --- a/drivers/media/video/videobuf2-dma-contig.c +++ b/drivers/media/video/videobuf2-dma-contig.c @@ -18,12 +18,8 @@ #include <media/videobuf2-dma-contig.h> #include <media/videobuf2-memops.h>

-struct vb2_dc_conf { - struct device *dev; -}; - struct vb2_dc_buf { - struct vb2_dc_conf *conf; + struct device *dev; void *vaddr; dma_addr_t dma_addr; unsigned long size; @@ -36,23 +32,21 @@ static void vb2_dc_put(void *buf_priv);

static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size) { - struct vb2_dc_conf *conf = alloc_ctx; + struct device *dev = alloc_ctx; struct vb2_dc_buf *buf;

buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM);

- buf->vaddr = dma_alloc_coherent(conf->dev, size, &buf->dma_addr, - GFP_KERNEL); + buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL); if (!buf->vaddr) { - dev_err(conf->dev, "dma_alloc_coherent of size %ld failed\n", - size); + dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size); kfree(buf); return ERR_PTR(-ENOMEM); }

- buf->conf = conf; + buf->dev = dev; buf->size = size;

buf->handler.refcount = &buf->refcount; @@ -69,7 +63,7 @@ static void vb2_dc_put(void *buf_priv) struct vb2_dc_buf *buf = buf_priv;

if (atomic_dec_and_test(&buf->refcount)) { - dma_free_coherent(buf->conf->dev, buf->size, buf->vaddr, + dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr); kfree(buf); } @@ -163,21 +157,12 @@ EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);

void *vb2_dma_contig_init_ctx(struct device *dev) { - struct vb2_dc_conf *conf; - - conf = kzalloc(sizeof *conf, GFP_KERNEL); - if (!conf) - return ERR_PTR(-ENOMEM); - - conf->dev = dev; - - return conf; + return dev; } EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);

void vb2_dma_contig_cleanup_ctx(void *alloc_ctx) { - kfree(alloc_ctx); } EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);

This patch introduces usage of dma_map_sg to map memory behind a userspace pointer to a device as dma-contiguous mapping.

This patch contains some of the code kindly provided by Marek Szyprowski m.szyprowski@samsung.com and Kamil Debski k.debski@samsung.com and Andrzej Pietrasiewicz andrzej.p@samsung.com. Kind thanks for bug reports from Laurent Pinchart laurent.pinchart@ideasonboard.com and Seung-Woo Kim sw0312.kim@samsung.com.

Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com Acked-by: Laurent Pinchart laurent.pinchart@ideasonboard.com --- drivers/media/video/videobuf2-dma-contig.c | 268 ++++++++++++++++++++++++++-- 1 file changed, 252 insertions(+), 16 deletions(-)

diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c index 42c6431..068ec11 100644 --- a/drivers/media/video/videobuf2-dma-contig.c +++ b/drivers/media/video/videobuf2-dma-contig.c @@ -11,6 +11,8 @@ */

#include <linux/module.h> +#include <linux/scatterlist.h> +#include <linux/sched.h> #include <linux/slab.h> #include <linux/dma-mapping.h>

@@ -23,6 +25,8 @@ struct vb2_dc_buf { void *vaddr; unsigned long size; dma_addr_t dma_addr; + enum dma_data_direction dma_dir; + struct sg_table *dma_sgt;

/* MMAP related */ struct vb2_vmarea_handler handler; @@ -33,6 +37,95 @@ struct vb2_dc_buf { };

/*********************************************/ +/* scatterlist table functions */ +/*********************************************/ + +static struct sg_table *vb2_dc_pages_to_sgt(struct page **pages, + unsigned int n_pages, unsigned long offset, unsigned long size) +{ + struct sg_table *sgt; + unsigned int chunks; + unsigned int i; + unsigned int cur_page; + int ret; + struct scatterlist *s; + + sgt = kzalloc(sizeof *sgt, GFP_KERNEL); + if (!sgt) + return ERR_PTR(-ENOMEM); + + /* compute number of chunks */ + chunks = 1; + for (i = 1; i < n_pages; ++i) + if (pages[i] != pages[i - 1] + 1) + ++chunks; + + ret = sg_alloc_table(sgt, chunks, GFP_KERNEL); + if (ret) { + kfree(sgt); + return ERR_PTR(-ENOMEM); + } + + /* merging chunks and putting them into the scatterlist */ + cur_page = 0; + for_each_sg(sgt->sgl, s, sgt->orig_nents, i) { + unsigned long chunk_size; + unsigned int j; + + for (j = cur_page + 1; j < n_pages; ++j) + if (pages[j] != pages[j - 1] + 1) + break; + + chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; + sg_set_page(s, pages[cur_page], min(size, chunk_size), offset); + size -= chunk_size; + offset = 0; + cur_page = j; + } + + return sgt; +} + +static void vb2_dc_release_sgtable(struct sg_table *sgt) +{ + sg_free_table(sgt); + kfree(sgt); +} + +static void vb2_dc_sgt_foreach_page(struct sg_table *sgt, + void (*cb)(struct page *pg)) +{ + struct scatterlist *s; + unsigned int i; + + for_each_sg(sgt->sgl, s, sgt->nents, i) { + struct page *page = sg_page(s); + unsigned int n_pages = PAGE_ALIGN(s->offset + s->length) + >> PAGE_SHIFT; + unsigned int j; + + for (j = 0; j < n_pages; ++j, ++page) + cb(page); + } +} + +static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt) +{ + struct scatterlist *s; + dma_addr_t expected = sg_dma_address(sgt->sgl); + unsigned int i; + unsigned long size = 0; + + for_each_sg(sgt->sgl, s, sgt->nents, i) { + if (sg_dma_address(s) != expected) + break; + expected = sg_dma_address(s) + sg_dma_len(s); + size += sg_dma_len(s); + } + return size; +} + +/*********************************************/ /* callbacks for all buffers */ /*********************************************/

@@ -117,42 +210,185 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma) /* callbacks for USERPTR buffers */ /*********************************************/

+static inline int vma_is_io(struct vm_area_struct *vma) +{ + return !!(vma->vm_flags & (VM_IO | VM_PFNMAP)); +} + +static int vb2_dc_get_user_pages(unsigned long start, struct page **pages, + int n_pages, struct vm_area_struct *vma, int write) +{ + if (vma_is_io(vma)) { + unsigned int i; + + for (i = 0; i < n_pages; ++i, start += PAGE_SIZE) { + unsigned long pfn; + int ret = follow_pfn(vma, start, &pfn); + + if (ret) { + printk(KERN_ERR "no page for address %lu\n", + start); + return ret; + } + pages[i] = pfn_to_page(pfn); + } + } else { + int n; + + n = get_user_pages(current, current->mm, start & PAGE_MASK, + n_pages, write, 1, pages, NULL); + /* negative error means that no page was pinned */ + n = max(n, 0); + if (n != n_pages) { + printk(KERN_ERR "got only %d of %d user pages\n", + n, n_pages); + while (n) + put_page(pages[--n]); + return -EFAULT; + } + } + + return 0; +} + +static void vb2_dc_put_dirty_page(struct page *page) +{ + set_page_dirty_lock(page); + put_page(page); +} + +static void vb2_dc_put_userptr(void *buf_priv) +{ + struct vb2_dc_buf *buf = buf_priv; + struct sg_table *sgt = buf->dma_sgt; + + dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir); + if (!vma_is_io(buf->vma)) + vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page); + + vb2_dc_release_sgtable(sgt); + vb2_put_vma(buf->vma); + kfree(buf); +} + static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, - unsigned long size, int write) + unsigned long size, int write) { struct vb2_dc_buf *buf; + unsigned long start; + unsigned long end; + unsigned long offset; + struct page **pages; + int n_pages; + int ret = 0; struct vm_area_struct *vma; - dma_addr_t dma_addr = 0; - int ret; + struct sg_table *sgt; + unsigned long contig_size;

buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM);

- ret = vb2_get_contig_userptr(vaddr, size, &vma, &dma_addr); + buf->dev = alloc_ctx; + buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE; + + start = vaddr & PAGE_MASK; + offset = vaddr & ~PAGE_MASK; + end = PAGE_ALIGN(vaddr + size); + n_pages = (end - start) >> PAGE_SHIFT; + + pages = kmalloc(n_pages * sizeof pages[0], GFP_KERNEL); + if (!pages) { + ret = -ENOMEM; + printk(KERN_ERR "failed to allocate pages table\n"); + goto fail_buf; + } + + /* current->mm->mmap_sem is taken by videobuf2 core */ + vma = find_vma(current->mm, vaddr); + if (!vma) { + printk(KERN_ERR "no vma for address %lu\n", vaddr); + ret = -EFAULT; + goto fail_pages; + } + + if (vma->vm_end < vaddr + size) { + printk(KERN_ERR "vma at %lu is too small for %lu bytes\n", + vaddr, size); + ret = -EFAULT; + goto fail_pages; + } + + buf->vma = vb2_get_vma(vma); + if (!buf->vma) { + printk(KERN_ERR "failed to copy vma\n"); + ret = -ENOMEM; + goto fail_pages; + } + + /* extract page list from userspace mapping */ + ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write); if (ret) { - printk(KERN_ERR "Failed acquiring VMA for vaddr 0x%08lx\n", - vaddr); - kfree(buf); - return ERR_PTR(ret); + printk(KERN_ERR "failed to get user pages\n"); + goto fail_vma; + } + + sgt = vb2_dc_pages_to_sgt(pages, n_pages, offset, size); + if (IS_ERR(sgt)) { + printk(KERN_ERR "failed to create scatterlist table\n"); + ret = -ENOMEM; + goto fail_get_user_pages; }

+ /* pages are no longer needed */ + kfree(pages); + pages = NULL; + + sgt->nents = dma_map_sg(buf->dev, sgt->sgl, sgt->orig_nents, + buf->dma_dir); + if (sgt->nents <= 0) { + printk(KERN_ERR "failed to map scatterlist\n"); + ret = -EIO; + goto fail_sgt; + } + + contig_size = vb2_dc_get_contiguous_size(sgt); + if (contig_size < size) { + printk(KERN_ERR "contiguous mapping is too small %lu/%lu\n", + contig_size, size); + ret = -EFAULT; + goto fail_map_sg; + } + + buf->dma_addr = sg_dma_address(sgt->sgl); buf->size = size; - buf->dma_addr = dma_addr; - buf->vma = vma; + buf->dma_sgt = sgt;

return buf; -}

-static void vb2_dc_put_userptr(void *mem_priv) -{ - struct vb2_dc_buf *buf = mem_priv; +fail_map_sg: + dma_unmap_sg(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);

- if (!buf) - return; +fail_sgt: + if (!vma_is_io(buf->vma)) + vb2_dc_sgt_foreach_page(sgt, put_page); + vb2_dc_release_sgtable(sgt);

+fail_get_user_pages: + if (pages && !vma_is_io(buf->vma)) + while (n_pages) + put_page(pages[--n_pages]); + +fail_vma: vb2_put_vma(buf->vma); + +fail_pages: + kfree(pages); /* kfree is NULL-proof */ + +fail_buf: kfree(buf); + + return ERR_PTR(ret); }

/*********************************************/

From: Marek Szyprowski m.szyprowski@samsung.com

Add prepare/finish callbacks to vb2-dma-contig allocator.

Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com --- drivers/media/video/videobuf2-dma-contig.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)

diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c index 068ec11..bb32e7e 100644 --- a/drivers/media/video/videobuf2-dma-contig.c +++ b/drivers/media/video/videobuf2-dma-contig.c @@ -150,6 +150,28 @@ static unsigned int vb2_dc_num_users(void *buf_priv) return atomic_read(&buf->refcount); }

+static void vb2_dc_prepare(void *buf_priv) +{ + struct vb2_dc_buf *buf = buf_priv; + struct sg_table *sgt = buf->dma_sgt; + + if (!sgt) + return; + + dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); +} + +static void vb2_dc_finish(void *buf_priv) +{ + struct vb2_dc_buf *buf = buf_priv; + struct sg_table *sgt = buf->dma_sgt; + + if (!sgt) + return; + + dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir); +} + /*********************************************/ /* callbacks for MMAP buffers */ /*********************************************/ @@ -403,6 +425,8 @@ const struct vb2_mem_ops vb2_dma_contig_memops = { .mmap = vb2_dc_mmap, .get_userptr = vb2_dc_get_userptr, .put_userptr = vb2_dc_put_userptr, + .prepare = vb2_dc_prepare, + .finish = vb2_dc_finish, .num_users = vb2_dc_num_users, }; EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);

This patch enhances s5p-tv with support for DMABUF importing via V4L2_MEMORY_DMABUF memory type.

Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com --- drivers/media/video/s5p-tv/Kconfig | 1 + drivers/media/video/s5p-tv/mixer_video.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/video/s5p-tv/Kconfig b/drivers/media/video/s5p-tv/Kconfig index f248b28..2e80126 100644 --- a/drivers/media/video/s5p-tv/Kconfig +++ b/drivers/media/video/s5p-tv/Kconfig @@ -10,6 +10,7 @@ config VIDEO_SAMSUNG_S5P_TV bool "Samsung TV driver for S5P platform (experimental)" depends on PLAT_S5P && PM_RUNTIME depends on EXPERIMENTAL + select DMA_SHARED_BUFFER default n ---help--- Say Y here to enable selecting the TV output devices for diff --git a/drivers/media/video/s5p-tv/mixer_video.c b/drivers/media/video/s5p-tv/mixer_video.c index 33fde2a..cff974a 100644 --- a/drivers/media/video/s5p-tv/mixer_video.c +++ b/drivers/media/video/s5p-tv/mixer_video.c @@ -1078,7 +1078,7 @@ struct mxr_layer *mxr_base_layer_create(struct mxr_device *mdev,

layer->vb_queue = (struct vb2_queue) { .type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE, - .io_modes = VB2_MMAP | VB2_USERPTR, + .io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF, .drv_priv = layer, .buf_struct_size = sizeof(struct mxr_buffer), .ops = &mxr_video_qops,

Hi Tomasz,

Thanks for the patch.

On Wednesday 23 May 2012 14:10:15 Tomasz Stanislawski wrote:

From: Sumit Semwal sumit.semwal@ti.com

Adds DMABUF memory type to v4l framework. Also adds the related file descriptor in v4l2_plane and v4l2_buffer.

Sorry not to have caught this earlier, but haven't you forgotten to add support for V4L2_MEMORY_DMABUF to v4l2-compat-ioctl32.c ?

Signed-off-by: Tomasz Stanislawski t.stanislaws@samsung.com [original work in the PoC for buffer sharing] Signed-off-by: Sumit Semwal sumit.semwal@ti.com Signed-off-by: Sumit Semwal sumit.semwal@linaro.org Acked-by: Laurent Pinchart laurent.pinchart@ideasonboard.com

---

drivers/media/video/v4l2-ioctl.c | 1 + include/linux/videodev2.h | 7 +++++++ 2 files changed, 8 insertions(+)

diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c index 91be4e8..31fc2ad 100644 --- a/drivers/media/video/v4l2-ioctl.c +++ b/drivers/media/video/v4l2-ioctl.c @@ -175,6 +175,7 @@ static const char *v4l2_memory_names[] = { [V4L2_MEMORY_MMAP] = "mmap", [V4L2_MEMORY_USERPTR] = "userptr", [V4L2_MEMORY_OVERLAY] = "overlay",

• [V4L2_MEMORY_DMABUF] = "dmabuf",

};

#define prt_names(a, arr) ((((a) >= 0) && ((a) < ARRAY_SIZE(arr))) ? \ diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h index 370d111..51b20f4 100644 --- a/include/linux/videodev2.h +++ b/include/linux/videodev2.h @@ -185,6 +185,7 @@ enum v4l2_memory { V4L2_MEMORY_MMAP = 1, V4L2_MEMORY_USERPTR = 2, V4L2_MEMORY_OVERLAY = 3,

• V4L2_MEMORY_DMABUF = 4,

};

/* see also http://vektor.theorem.ca/graphics/ycbcr/ */ @@ -591,6 +592,8 @@ struct v4l2_requestbuffers {

• 	should be passed to mmap() called on the video node)
  

• @userptr: when memory is V4L2_MEMORY_USERPTR, a userspace pointer

• 	pointing to this plane
  

• • @fd: when memory is V4L2_MEMORY_DMABUF, a userspace file

• • 	descriptor associated with this plane
    

  • @data_offset: offset in the plane to the start of data; usually 0,

  • 	unless there is a header in front of the data
    

@@ -605,6 +608,7 @@ struct v4l2_plane { union { __u32 mem_offset; unsigned long userptr;

• int		fd;
  

  } m; __u32 data_offset; __u32 reserved[11];

@@ -629,6 +633,8 @@ struct v4l2_plane {

• (or a "cookie" that should be passed to mmap() as offset)
  

• @userptr: for non-multiplanar buffers with memory ==

V4L2_MEMORY_USERPTR; * a userspace pointer pointing to this buffer

• • @fd: for non-multiplanar buffers with memory ==

V4L2_MEMORY_DMABUF;

• • a userspace file descriptor associated with this buffer
    

  • @planes: for multiplanar buffers; userspace pointer to the array of

plane * info structs for this buffer

• @length: size in bytes of the buffer (NOT its payload) for single-

plane

@@ -655,6 +661,7 @@ struct v4l2_buffer { __u32 offset; unsigned long userptr; struct v4l2_plane *planes;

• int		fd;
  

  } m; __u32 length; __u32 input;