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Message-ID: <164584fc-a0c3-7988-fc43-8b3f19d46988@collabora.com>
Date: Mon, 23 Nov 2020 17:33:16 -0300
From: Helen Koike <helen.koike@...labora.com>
To: Tomasz Figa <tfiga@...omium.org>
Cc: mchehab@...nel.org, hans.verkuil@...co.com,
laurent.pinchart@...asonboard.com, sakari.ailus@....fi,
linux-media@...r.kernel.org,
Boris Brezillon <boris.brezillon@...labora.com>,
hiroh@...omium.org, nicolas@...fresne.ca, Brian.Starkey@....com,
kernel@...labora.com, narmstrong@...libre.com,
linux-kernel@...r.kernel.org, frkoenig@...omium.org,
mjourdan@...libre.com, stanimir.varbanov@...aro.org
Subject: Re: [PATCH v5 2/7] media: v4l2: Add extended buffer operations
Hi Tomasz,
On 11/20/20 8:14 AM, Tomasz Figa wrote:
> Hi Helen,
>
> On Tue, Aug 04, 2020 at 04:29:34PM -0300, Helen Koike wrote:
>> From: Hans Verkuil <hans.verkuil@...co.com>
>>
>> Those extended buffer ops have several purpose:
>> 1/ Fix y2038 issues by converting the timestamp into an u64 counting
>> the number of ns elapsed since 1970
>> 2/ Unify single/multiplanar handling
>> 3/ Add a new start offset field to each v4l2 plane buffer info struct
>> to support the case where a single buffer object is storing all
>> planes data, each one being placed at a different offset
>>
>> New hooks are created in v4l2_ioctl_ops so that drivers can start using
>> these new objects.
>>
>> The core takes care of converting new ioctls requests to old ones
>> if the driver does not support the new hooks, and vice versa.
>>
>> Note that the timecode field is gone, since there doesn't seem to be
>> in-kernel users. We can be added back in the reserved area if needed or
>> use the Request API to collect more metadata information from the
>> frame.
>>
>
> Thanks for the patch. Please see my comments inline.
Thank you for your detailed review, please see my comments below.
>
>> Signed-off-by: Hans Verkuil <hans.verkuil@...co.com>
>> Signed-off-by: Boris Brezillon <boris.brezillon@...labora.com>
>> Signed-off-by: Helen Koike <helen.koike@...labora.com>
>> ---
>> Changes in v5:
>> - migrate memory from v4l2_ext_buffer to v4l2_ext_plane
>> - return mem_offset to struct v4l2_ext_plane
>> - change sizes and reorder fields to avoid holes in the struct and make
>> it the same for 32 and 64 bits
>>
>> Changes in v4:
>> - Use v4l2_ext_pix_format directly in the ioctl, drop v4l2_ext_format,
>> making V4L2_BUF_TYPE_VIDEO_[OUTPUT,CAPTURE] the only valid types.
>> - Drop VIDIOC_EXT_EXPBUF, since the only difference from VIDIOC_EXPBUF
>> was that with VIDIOC_EXT_EXPBUF we could export multiple planes at once.
>> I think we can add this later, so I removed it from this RFC to simplify it.
>> - Remove num_planes field from struct v4l2_ext_buffer
>> - Add flags field to struct v4l2_ext_create_buffers
>> - Reformulate struct v4l2_ext_plane
>> - Fix some bugs caught by v4l2-compliance
>> - Rebased on top of media/master (post 5.8-rc1)
>>
>> Changes in v3:
>> - Rebased on top of media/master (post 5.4-rc1)
>>
>> Changes in v2:
>> - Add reserved space to v4l2_ext_buffer so that new fields can be added
>> later on
>> ---
>> drivers/media/v4l2-core/v4l2-dev.c | 29 ++-
>> drivers/media/v4l2-core/v4l2-ioctl.c | 353 +++++++++++++++++++++++++--
>> include/media/v4l2-ioctl.h | 26 ++
>> include/uapi/linux/videodev2.h | 90 +++++++
>> 4 files changed, 476 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
>> index e1829906bc086..cb21ee8eb075c 100644
>> --- a/drivers/media/v4l2-core/v4l2-dev.c
>> +++ b/drivers/media/v4l2-core/v4l2-dev.c
>> @@ -720,15 +720,34 @@ static void determine_valid_ioctls(struct video_device *vdev)
>> SET_VALID_IOCTL(ops, VIDIOC_TRY_FMT, vidioc_try_fmt_sdr_out);
>> }
>>
>> + if (is_vid || is_tch) {
>> + /* ioctls valid for video and touch */
>> + if (ops->vidioc_querybuf || ops->vidioc_ext_querybuf)
>> + set_bit(_IOC_NR(VIDIOC_EXT_QUERYBUF), valid_ioctls);
>> + if (ops->vidioc_qbuf || ops->vidioc_ext_qbuf)
>> + set_bit(_IOC_NR(VIDIOC_EXT_QBUF), valid_ioctls);
>> + if (ops->vidioc_dqbuf || ops->vidioc_ext_dqbuf)
>> + set_bit(_IOC_NR(VIDIOC_EXT_DQBUF), valid_ioctls);
>> + if (ops->vidioc_create_bufs || ops->vidioc_ext_create_bufs)
>> + set_bit(_IOC_NR(VIDIOC_EXT_CREATE_BUFS), valid_ioctls);
>> + if (ops->vidioc_prepare_buf || ops->vidioc_ext_prepare_buf)
>> + set_bit(_IOC_NR(VIDIOC_EXT_PREPARE_BUF), valid_ioctls);
>
> nit: Could we stick to the SET_VALID_IOCTL() macro and just call it twice,
> once for the new and once for the legacy callback?
Ack.
>
>> + }
>> +
>> if (is_vid || is_vbi || is_sdr || is_tch || is_meta) {
>> /* ioctls valid for video, vbi, sdr, touch and metadata */
>> SET_VALID_IOCTL(ops, VIDIOC_REQBUFS, vidioc_reqbufs);
>> - SET_VALID_IOCTL(ops, VIDIOC_QUERYBUF, vidioc_querybuf);
>> - SET_VALID_IOCTL(ops, VIDIOC_QBUF, vidioc_qbuf);
>> SET_VALID_IOCTL(ops, VIDIOC_EXPBUF, vidioc_expbuf);
>> - SET_VALID_IOCTL(ops, VIDIOC_DQBUF, vidioc_dqbuf);
>> - SET_VALID_IOCTL(ops, VIDIOC_CREATE_BUFS, vidioc_create_bufs);
>> - SET_VALID_IOCTL(ops, VIDIOC_PREPARE_BUF, vidioc_prepare_buf);
>> + if (ops->vidioc_querybuf || ops->vidioc_ext_querybuf)
>> + set_bit(_IOC_NR(VIDIOC_QUERYBUF), valid_ioctls);
>> + if (ops->vidioc_qbuf || ops->vidioc_ext_qbuf)
>> + set_bit(_IOC_NR(VIDIOC_QBUF), valid_ioctls);
>> + if (ops->vidioc_dqbuf || ops->vidioc_ext_dqbuf)
>> + set_bit(_IOC_NR(VIDIOC_DQBUF), valid_ioctls);
>> + if (ops->vidioc_create_bufs || ops->vidioc_ext_create_bufs)
>> + set_bit(_IOC_NR(VIDIOC_CREATE_BUFS), valid_ioctls);
>> + if (ops->vidioc_prepare_buf || ops->vidioc_ext_prepare_buf)
>> + set_bit(_IOC_NR(VIDIOC_PREPARE_BUF), valid_ioctls);
>
> Is it valid to check the new callbacks for devices that the new API is not
> valid for (e.g. vbi)? Perhaps we could call SET_VALID_IOCTL(ops, <ioctl>,
> vidioc_ext_*) in the upper if added in this patch and keep the code above
> as is?
Just to be clear, the only valid type should be VFL_TYPE_VIDEO right?
Ext but API won't support touch devices for instance, right?
>
>> SET_VALID_IOCTL(ops, VIDIOC_STREAMON, vidioc_streamon);
>> SET_VALID_IOCTL(ops, VIDIOC_STREAMOFF, vidioc_streamoff);
>> }
>> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
>> index 14a0def50f8ea..7ecdd9cc1bf48 100644
>> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
>> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
>> @@ -527,6 +527,26 @@ static void v4l_print_buffer(const void *arg, bool write_only)
>> tc->type, tc->flags, tc->frames, *(__u32 *)tc->userbits);
>> }
>>
>> +static void v4l_print_ext_buffer(const void *arg, bool write_only)
>> +{
>> + const struct v4l2_ext_buffer *e = arg;
>> + const struct v4l2_ext_plane *plane;
>> + unsigned int i;
>> +
>> + pr_cont("%lld index=%d, type=%s, flags=0x%08x, field=%s, sequence=%d\n",
>> + e->timestamp, e->index, prt_names(e->type, v4l2_type_names),
>> + e->flags, prt_names(e->field, v4l2_field_names), e->sequence);
>
> Should we also print the request FD?
Yes, I'll update this for next version.
>
>> +
>> + for (i = 0; i < VIDEO_MAX_PLANES &&
>> + e->planes[i].buffer_length; i++) {
>> + plane = &e->planes[i];
>> + pr_debug("plane %d: buffer_length=%d, plane_length=%d offset=0x%08x, memory=%s\n",
>> + i, plane->buffer_length, plane->plane_length,
>> + plane->offset,
>> + prt_names(plane->memory, v4l2_memory_names));
>
> Should we also print mem_offset/userptr/dmabuf_fd?
I see they are not printed by v4l_print_buffer(), since these fields are in an
union, the value of two of them will be invalid (I wonder if this can bring
confusion).
I also wondered if printing them can't cause a security issue.
But I can add those prints if you think it make sense.
>
>> + }
>> +}
>> +
>> static void v4l_print_exportbuffer(const void *arg, bool write_only)
>> {
>> const struct v4l2_exportbuffer *p = arg;
>> @@ -546,6 +566,15 @@ static void v4l_print_create_buffers(const void *arg, bool write_only)
>> v4l_print_format(&p->format, write_only);
>> }
>>
>> +static void v4l_print_ext_create_buffers(const void *arg, bool write_only)
>> +{
>> + const struct v4l2_ext_create_buffers *p = arg;
>> +
>> + pr_cont("index=%d, count=%d, memory=%s, ", p->index, p->count,
>> + prt_names(p->memory, v4l2_memory_names));
>> + v4l_print_ext_pix_format(&p->format, write_only);
>
> Should we also print capabilities and flags?
I just saw these prints are called after the ioctl handler, and not before,
to I guess it make sense.
It is not printed by v4l_print_create_buffers(), I think we can add in both then.
>
>> +}
>> +
>> static void v4l_print_streamparm(const void *arg, bool write_only)
>> {
>> const struct v4l2_streamparm *p = arg;
>> @@ -1220,6 +1249,143 @@ int v4l2_format_to_ext_pix_format(const struct v4l2_format *f,
>> }
>> EXPORT_SYMBOL_GPL(v4l2_format_to_ext_pix_format);
>>
>> +/*
>> + * If mplane_cap is true, b->m.planes should have a valid pointer of a
>> + * struct v4l2_plane array, and b->length with its size
>> + */
>> +int v4l2_ext_buffer_to_buffer(const struct v4l2_ext_buffer *e,
>> + struct v4l2_buffer *b, bool mplane_cap)
>> +{
>> + unsigned int planes_array_size = b->length;
>> + struct v4l2_plane *planes = b->m.planes;
>> + u64 nsecs;
>> +
>> + if (!mplane_cap && e->planes[1].buffer_length != 0)
>> + return -EINVAL;
>> +
>> + memset(b, 0, sizeof(*b));
>> +
>> + b->index = e->index;
>> + b->flags = e->flags;
>> + b->field = e->field;
>> + b->sequence = e->sequence;
>> + b->memory = e->planes[0].memory;
>> + b->request_fd = e->request_fd;
>> + b->timestamp.tv_sec = div64_u64_rem(e->timestamp, NSEC_PER_SEC, &nsecs);
>> + b->timestamp.tv_usec = (u32)nsecs / NSEC_PER_USEC;
>> +
>> + if (mplane_cap) {
>> + unsigned int i;
>> +
>> + if (!planes || !planes_array_size)
>> + return -EINVAL;
>> +
>> + b->m.planes = planes;
>
> planes was initialized to b->m.planes at declaration time. Should we
> perhaps move its declaration to within this block to make it more clear and
> remove this assignment?
The variable "planes" is saving the pointer of b->m.planes before we do
memset(b, 0, sizeof(*b)), so I can reassing it back if it make sense.
I can add a comment to make this more clear.
>
>> +
>> + if (e->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
>> + b->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
>> + else
>> + b->type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
>> +
>> + for (i = 0; i < VIDEO_MAX_PLANES && i < planes_array_size &&
>> + e->planes[i].buffer_length; i++) {
>> +
>> + if (e->planes[0].memory != e->planes[i].memory)
>> + return -EINVAL;
>> +
>> + if (e->planes[i].offset)
>> + return -EINVAL;
>
> Is it really invalid to have a non-zero offset? Shouldn't the data_offset
> field of the legacy struct be populated instead, in the cases where it was
> defined to be valid?
My understanding of data_offset, is that it is used when the hardware can
write/read a header to/from the buffer.
But this doesn't seem to be used by any driver, so there is an attempt to
repourpose it here:
https://patchwork.linuxtv.org/project/linux-media/patch/1429040689-23808-2-git-send-email-laurent.pinchart@ideasonboard.com/
But this wans't merged.
So in the current API, there is no way to specify an offset in the buffer.
I guess we can repurpose data_offset first, what do you think?
>
>> +
>> + memset(&b->m.planes[i], 0, sizeof(b->m.planes[i]));
>> +
>> + if (b->memory == V4L2_MEMORY_MMAP)
>> + b->m.planes[i].m.mem_offset = e->planes[i].m.mem_offset;
>> + else if (b->memory == V4L2_MEMORY_DMABUF)
>> + b->m.planes[i].m.fd = e->planes[i].m.dmabuf_fd;
>> + else
>> + b->m.planes[i].m.userptr = e->planes[i].m.userptr;
>> +
>> + b->m.planes[i].bytesused = e->planes[i].plane_length;
>
> I might be getting the meaning of plane_length wrong, but doesn't this
> depend on the direction? If the userspace gives a CAPTURE buffer, it would
> have bytesused = 0, but if the kernel returns it, it would have bytesused =
> <size of the payload>.
You are right, it depends on the direction, thanks for catching this.
Also, in the Ext api, we don't have the <size of the payload>, so I'm using the
plane_length instead, I'm not sure if there is a better way.
>
>> + b->m.planes[i].length = e->planes[i].buffer_length;
>> + }
>> + /* In multi-planar, length contain the number of planes */
>> + b->length = i;
>> + } else {
>> + b->type = e->type;
>> + b->bytesused = e->planes[0].plane_length;
>> + b->length = e->planes[0].buffer_length;
>> +
>> + if (e->planes[0].offset)
>> + return -EINVAL;
>
> Ditto.
Ack.
>
>> +
>> + if (b->memory == V4L2_MEMORY_MMAP)
>> + b->m.offset = e->planes[0].m.mem_offset;
>> + else if (b->memory == V4L2_MEMORY_DMABUF)
>> + b->m.fd = e->planes[0].m.dmabuf_fd;
>> + else
>> + b->m.userptr = e->planes[0].m.userptr;
>> + }
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(v4l2_ext_buffer_to_buffer);
>> +
>> +int v4l2_buffer_to_ext_buffer(const struct v4l2_buffer *b,
>> + struct v4l2_ext_buffer *e)
>> +{
>> + memset(e, 0, sizeof(*e));
>> +
>> + e->index = b->index;
>> + e->flags = b->flags;
>> + e->field = b->field;
>> + e->sequence = b->sequence;
>> + e->request_fd = b->request_fd;
>> + e->timestamp = b->timestamp.tv_sec * NSEC_PER_SEC +
>> + b->timestamp.tv_usec * NSEC_PER_USEC;
>> + if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
>> + unsigned int i;
>> +
>> + if (!b->m.planes)
>> + return -EINVAL;
>> +
>> + if (b->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE)
>> + e->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
>> + else
>> + e->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
>> +
>> + /* In multi-planar, length contain the number of planes */
>> + for (i = 0; i < b->length; i++) {
>
> The design of the new struct implies that the planes describe color planes
> and not memory planes, so this code is incorrect, because for non-M format
> variants it would fill in only the first plane of the new struct.
Yes, as discussed in 1/7, the handling of planes is wrong, I'll correct
this for next version.
>
>> + if (b->memory == V4L2_MEMORY_MMAP)
>> + e->planes[i].m.mem_offset = b->m.planes[i].m.mem_offset;
>> + else if (b->memory == V4L2_MEMORY_DMABUF)
>> + e->planes[i].m.dmabuf_fd = b->m.planes[i].m.fd;
>> + else
>> + e->planes[i].m.userptr = b->m.planes[i].m.userptr;
>> +
>> + e->planes[i].memory = b->memory;
>> + e->planes[i].buffer_length = b->m.planes[i].length;
>> + e->planes[i].plane_length = b->m.planes[i].bytesused;
>> + if (b->m.planes[i].data_offset)
>> + pr_warn("Ignoring data_offset value %d\n",
>> + b->m.planes[i].data_offset);
>
> Why? As per my comment above, there are valid use cases defined in the spec.
Please see my comment about about data_offset.
>
>> + }
>> + } else {
>> + e->type = b->type;
>> + e->planes[0].memory = b->memory;
>> + e->planes[0].plane_length = b->bytesused;
>> + e->planes[0].buffer_length = b->length;
>> + if (b->memory == V4L2_MEMORY_MMAP)
>> + e->planes[0].m.mem_offset = b->m.offset;
>> + else if (b->memory == V4L2_MEMORY_DMABUF)
>> + e->planes[0].m.dmabuf_fd = b->m.fd;
>> + else
>> + e->planes[0].m.userptr = b->m.userptr;
>
> Similar to the MULTIPLANAR case, we should fill in the planes[] entries
> corresponding to the number of color planes of the format, e.g. 2 for NV12.
Ack.
>
>> + }
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(v4l2_buffer_to_ext_buffer);
>> +
>> static int v4l_querycap(const struct v4l2_ioctl_ops *ops,
>> struct file *file, void *fh, void *arg)
>> {
>> @@ -2473,31 +2639,112 @@ static int v4l_reqbufs(const struct v4l2_ioctl_ops *ops,
>> return ops->vidioc_reqbufs(file, fh, p);
>> }
>>
>> +static int v4l_do_buf_op(int (*op)(struct file *, void *,
>> + struct v4l2_buffer *),
>> + int (*ext_op)(struct file *, void *,
>> + struct v4l2_ext_buffer *),
>> + struct file *file, void *fh, struct v4l2_buffer *b)
>> +{
>> + struct v4l2_ext_buffer e;
>> + int ret;
>> +
>> + ret = check_fmt(file, b->type);
>> + if (ret)
>> + return ret;
>> +
>> + if (op)
>> + return op(file, fh, b);
>> +
>> + ret = v4l2_buffer_to_ext_buffer(b, &e);
>> + if (ret)
>> + return ret;
>> +
>> + ret = ext_op(file, fh, &e);
>> + if (ret)
>> + return ret;
>> +
>> + v4l2_ext_buffer_to_buffer(&e, b, V4L2_TYPE_IS_MULTIPLANAR(b->type));
>> + return 0;
>> +}
>> +
>> +static int v4l_do_ext_buf_op(int (*op)(struct file *, void *,
>> + struct v4l2_buffer *),
>> + int (*ext_op)(struct file *, void *,
>> + struct v4l2_ext_buffer *),
>> + struct file *file, void *fh,
>> + struct v4l2_ext_buffer *e)
>> +{
>> + struct video_device *vdev = video_devdata(file);
>> + struct v4l2_plane planes[VIDEO_MAX_PLANES];
>> + struct v4l2_buffer b;
>> + bool mplane_cap;
>> + int ret;
>> +
>> + ret = check_fmt(file, e->type);
>> + if (ret)
>> + return ret;
>> +
>> + if (ext_op)
>> + return ext_op(file, fh, e);
>> +
>> + mplane_cap = !!(vdev->device_caps &
>> + (V4L2_CAP_VIDEO_CAPTURE_MPLANE |
>> + V4L2_CAP_VIDEO_OUTPUT_MPLANE |
>> + V4L2_CAP_VIDEO_M2M_MPLANE));
>> + b.m.planes = planes;
>> + b.length = VIDEO_MAX_PLANES;
>> + ret = v4l2_ext_buffer_to_buffer(e, &b, mplane_cap);
>> + if (ret)
>> + return ret;
>> +
>> + ret = op(file, fh, &b);
>> + if (ret)
>> + return ret;
>> +
>> + v4l2_buffer_to_ext_buffer(&b, e);
>> + return 0;
>> +}
>> +
>> static int v4l_querybuf(const struct v4l2_ioctl_ops *ops,
>> - struct file *file, void *fh, void *arg)
>> + struct file *file, void *fh, void *arg)
>> {
>> - struct v4l2_buffer *p = arg;
>> - int ret = check_fmt(file, p->type);
>> + return v4l_do_buf_op(ops->vidioc_querybuf, ops->vidioc_ext_querybuf,
>> + file, fh, arg);
>> +}
>>
>> - return ret ? ret : ops->vidioc_querybuf(file, fh, p);
>> +static int v4l_ext_querybuf(const struct v4l2_ioctl_ops *ops,
>> + struct file *file, void *fh, void *arg)
>> +{
>> + return v4l_do_ext_buf_op(ops->vidioc_querybuf,
>> + ops->vidioc_ext_querybuf, file, fh, arg);
>> }
>>
>> static int v4l_qbuf(const struct v4l2_ioctl_ops *ops,
>> - struct file *file, void *fh, void *arg)
>> + struct file *file, void *fh, void *arg)
>> {
>> - struct v4l2_buffer *p = arg;
>> - int ret = check_fmt(file, p->type);
>> + return v4l_do_buf_op(ops->vidioc_qbuf, ops->vidioc_ext_qbuf,
>> + file, fh, arg);
>> +}
>>
>> - return ret ? ret : ops->vidioc_qbuf(file, fh, p);
>> +static int v4l_ext_qbuf(const struct v4l2_ioctl_ops *ops,
>> + struct file *file, void *fh, void *arg)
>> +{
>> + return v4l_do_ext_buf_op(ops->vidioc_qbuf, ops->vidioc_ext_qbuf,
>> + file, fh, arg);
>> }
>>
>> static int v4l_dqbuf(const struct v4l2_ioctl_ops *ops,
>> - struct file *file, void *fh, void *arg)
>> + struct file *file, void *fh, void *arg)
>> {
>> - struct v4l2_buffer *p = arg;
>> - int ret = check_fmt(file, p->type);
>> + return v4l_do_buf_op(ops->vidioc_dqbuf, ops->vidioc_ext_dqbuf,
>> + file, fh, arg);
>> +}
>>
>> - return ret ? ret : ops->vidioc_dqbuf(file, fh, p);
>> +static int v4l_ext_dqbuf(const struct v4l2_ioctl_ops *ops,
>> + struct file *file, void *fh, void *arg)
>> +{
>> + return v4l_do_ext_buf_op(ops->vidioc_dqbuf, ops->vidioc_ext_dqbuf,
>> + file, fh, arg);
>> }
>>
>> static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops,
>> @@ -2513,7 +2760,27 @@ static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops,
>>
>> v4l_sanitize_format(&create->format);
>>
>> - ret = ops->vidioc_create_bufs(file, fh, create);
>> + if (ops->vidioc_create_bufs) {
>> + ret = ops->vidioc_create_bufs(file, fh, create);
>> + } else {
>> + struct v4l2_ext_create_buffers ecreate = {
>> + .count = create->count,
>> + .memory = create->memory,
>> + };
>> +
>> + ret = v4l2_format_to_ext_pix_format(&create->format,
>> + &ecreate.format, true);
>> + if (ret)
>> + return ret;
>> +
>> + ret = ops->vidioc_ext_create_bufs(file, fh, &ecreate);
>> + if (ret)
>> + return ret;
>> +
>> + create->index = ecreate.index;
>> + create->count = ecreate.count;
>> + create->capabilities = ecreate.capabilities;
>> + }
>>
>> if (create->format.type == V4L2_BUF_TYPE_VIDEO_CAPTURE ||
>> create->format.type == V4L2_BUF_TYPE_VIDEO_OUTPUT)
>> @@ -2522,13 +2789,60 @@ static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops,
>> return ret;
>> }
>>
>> +static int v4l_ext_create_bufs(const struct v4l2_ioctl_ops *ops,
>> + struct file *file, void *fh, void *arg)
>> +{
>> + struct v4l2_ext_create_buffers *ecreate = arg;
>> + struct video_device *vdev = video_devdata(file);
>> + struct v4l2_create_buffers create = {
>> + .count = ecreate->count,
>> + .memory = ecreate->memory,
>> + .flags = ecreate->flags,
>> + };
>> + bool mplane_cap;
>> + int ret;
>> +
>> + ret = check_fmt(file, ecreate->format.type);
>> + if (ret)
>> + return ret;
>> +
>> + if (ops->vidioc_ext_create_bufs)
>> + return ops->vidioc_ext_create_bufs(file, fh, ecreate);
>> +
>> + mplane_cap = !!(vdev->device_caps &
>> + (V4L2_CAP_VIDEO_CAPTURE_MPLANE |
>> + V4L2_CAP_VIDEO_OUTPUT_MPLANE |
>> + V4L2_CAP_VIDEO_M2M_MPLANE));
>> + ret = v4l2_ext_pix_format_to_format(&ecreate->format,
>> + &create.format, mplane_cap, true);
>> + if (ret)
>> + return ret;
>> +
>> + ret = v4l_create_bufs(ops, file, fh, &create);
>> + if (ret)
>> + return ret;
>> +
>> + ecreate->index = create.index;
>> + ecreate->count = create.count;
>> + ecreate->capabilities = create.capabilities;
>> +
>> + return 0;
>> +}
>> +
>> static int v4l_prepare_buf(const struct v4l2_ioctl_ops *ops,
>> - struct file *file, void *fh, void *arg)
>> + struct file *file, void *fh, void *arg)
>> {
>> - struct v4l2_buffer *b = arg;
>> - int ret = check_fmt(file, b->type);
>> + return v4l_do_buf_op(ops->vidioc_prepare_buf,
>> + ops->vidioc_ext_prepare_buf,
>> + file, fh, arg);
>> +}
>>
>> - return ret ? ret : ops->vidioc_prepare_buf(file, fh, b);
>> +static int v4l_ext_prepare_buf(const struct v4l2_ioctl_ops *ops,
>> + struct file *file, void *fh, void *arg)
>> +{
>> + return v4l_do_ext_buf_op(ops->vidioc_prepare_buf,
>> + ops->vidioc_ext_prepare_buf,
>> + file, fh, arg);
>> }
>>
>> static int v4l_g_parm(const struct v4l2_ioctl_ops *ops,
>> @@ -3202,12 +3516,15 @@ static const struct v4l2_ioctl_info v4l2_ioctls[] = {
>> IOCTL_INFO(VIDIOC_S_EXT_PIX_FMT, v4l_s_ext_pix_fmt, v4l_print_ext_pix_format, INFO_FL_PRIO),
>> IOCTL_INFO(VIDIOC_REQBUFS, v4l_reqbufs, v4l_print_requestbuffers, INFO_FL_PRIO | INFO_FL_QUEUE),
>> IOCTL_INFO(VIDIOC_QUERYBUF, v4l_querybuf, v4l_print_buffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_buffer, length)),
>> + IOCTL_INFO(VIDIOC_EXT_QUERYBUF, v4l_ext_querybuf, v4l_print_ext_buffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_ext_buffer, planes)),
>> IOCTL_INFO(VIDIOC_G_FBUF, v4l_stub_g_fbuf, v4l_print_framebuffer, 0),
>> IOCTL_INFO(VIDIOC_S_FBUF, v4l_stub_s_fbuf, v4l_print_framebuffer, INFO_FL_PRIO),
>> IOCTL_INFO(VIDIOC_OVERLAY, v4l_overlay, v4l_print_u32, INFO_FL_PRIO),
>> IOCTL_INFO(VIDIOC_QBUF, v4l_qbuf, v4l_print_buffer, INFO_FL_QUEUE),
>> IOCTL_INFO(VIDIOC_EXPBUF, v4l_stub_expbuf, v4l_print_exportbuffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_exportbuffer, flags)),
>> + IOCTL_INFO(VIDIOC_EXT_QBUF, v4l_ext_qbuf, v4l_print_ext_buffer, INFO_FL_QUEUE),
>
> Looking at the other entries, shouldn't this one be 1 line higher?
Yes.
>
> That said, I wonder if it wouldn't look cleaner if we just put all the
> EXT ioctls together at the bottom.
I can move them and we can see if it is better or not.
>
>> IOCTL_INFO(VIDIOC_DQBUF, v4l_dqbuf, v4l_print_buffer, INFO_FL_QUEUE),
>> + IOCTL_INFO(VIDIOC_EXT_DQBUF, v4l_ext_dqbuf, v4l_print_ext_buffer, INFO_FL_QUEUE),
>> IOCTL_INFO(VIDIOC_STREAMON, v4l_streamon, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),
>> IOCTL_INFO(VIDIOC_STREAMOFF, v4l_streamoff, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),
>> IOCTL_INFO(VIDIOC_G_PARM, v4l_g_parm, v4l_print_streamparm, INFO_FL_CLEAR(v4l2_streamparm, type)),
>> @@ -3272,7 +3589,9 @@ static const struct v4l2_ioctl_info v4l2_ioctls[] = {
>> IOCTL_INFO(VIDIOC_SUBSCRIBE_EVENT, v4l_subscribe_event, v4l_print_event_subscription, 0),
>> IOCTL_INFO(VIDIOC_UNSUBSCRIBE_EVENT, v4l_unsubscribe_event, v4l_print_event_subscription, 0),
>> IOCTL_INFO(VIDIOC_CREATE_BUFS, v4l_create_bufs, v4l_print_create_buffers, INFO_FL_PRIO | INFO_FL_QUEUE),
>> + IOCTL_INFO(VIDIOC_EXT_CREATE_BUFS, v4l_ext_create_bufs, v4l_print_ext_create_buffers, INFO_FL_PRIO | INFO_FL_QUEUE),
>> IOCTL_INFO(VIDIOC_PREPARE_BUF, v4l_prepare_buf, v4l_print_buffer, INFO_FL_QUEUE),
>> + IOCTL_INFO(VIDIOC_EXT_PREPARE_BUF, v4l_ext_prepare_buf, v4l_print_ext_buffer, INFO_FL_QUEUE),
>> IOCTL_INFO(VIDIOC_ENUM_DV_TIMINGS, v4l_stub_enum_dv_timings, v4l_print_enum_dv_timings, INFO_FL_CLEAR(v4l2_enum_dv_timings, pad)),
>> IOCTL_INFO(VIDIOC_QUERY_DV_TIMINGS, v4l_stub_query_dv_timings, v4l_print_dv_timings, INFO_FL_ALWAYS_COPY),
>> IOCTL_INFO(VIDIOC_DV_TIMINGS_CAP, v4l_stub_dv_timings_cap, v4l_print_dv_timings_cap, INFO_FL_CLEAR(v4l2_dv_timings_cap, pad)),
>> diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
>> index 8bbcb74d8ee31..75996657ad1ba 100644
>> --- a/include/media/v4l2-ioctl.h
>> +++ b/include/media/v4l2-ioctl.h
>> @@ -169,16 +169,26 @@ struct v4l2_fh;
>> * :ref:`VIDIOC_REQBUFS <vidioc_reqbufs>` ioctl
>> * @vidioc_querybuf: pointer to the function that implements
>> * :ref:`VIDIOC_QUERYBUF <vidioc_querybuf>` ioctl
>> + * @vidioc_ext_querybuf: pointer to the function that implements
>> + * :ref:`VIDIOC_EXT_QUERYBUF <vidioc_ext_querybuf>` ioctl
>> * @vidioc_qbuf: pointer to the function that implements
>> * :ref:`VIDIOC_QBUF <vidioc_qbuf>` ioctl
>> + * @vidioc_ext_qbuf: pointer to the function that implements
>> + * :ref:`VIDIOC_EXT_QBUF <vidioc_ext_qbuf>` ioctl
>> * @vidioc_expbuf: pointer to the function that implements
>> * :ref:`VIDIOC_EXPBUF <vidioc_expbuf>` ioctl
>> * @vidioc_dqbuf: pointer to the function that implements
>> * :ref:`VIDIOC_DQBUF <vidioc_qbuf>` ioctl
>> + * @vidioc_ext_dqbuf: pointer to the function that implements
>> + * :ref:`VIDIOC_EXT_DQBUF <vidioc_ext_qbuf>` ioctl
>> * @vidioc_create_bufs: pointer to the function that implements
>> * :ref:`VIDIOC_CREATE_BUFS <vidioc_create_bufs>` ioctl
>> + * @vidioc_ext_create_bufs: pointer to the function that implements
>> + * :ref:`VIDIOC_EXT_CREATE_BUFS <vidioc_ext_create_bufs>` ioctl
>> * @vidioc_prepare_buf: pointer to the function that implements
>> * :ref:`VIDIOC_PREPARE_BUF <vidioc_prepare_buf>` ioctl
>> + * @vidioc_ext_prepare_buf: pointer to the function that implements
>> + * :ref:`VIDIOC_EXT_PREPARE_BUF <vidioc_ext_prepare_buf>` ioctl
>> * @vidioc_overlay: pointer to the function that implements
>> * :ref:`VIDIOC_OVERLAY <vidioc_overlay>` ioctl
>> * @vidioc_g_fbuf: pointer to the function that implements
>> @@ -439,17 +449,27 @@ struct v4l2_ioctl_ops {
>> struct v4l2_requestbuffers *b);
>> int (*vidioc_querybuf)(struct file *file, void *fh,
>> struct v4l2_buffer *b);
>> + int (*vidioc_ext_querybuf)(struct file *file, void *fh,
>> + struct v4l2_ext_buffer *b);
>> int (*vidioc_qbuf)(struct file *file, void *fh,
>> struct v4l2_buffer *b);
>> + int (*vidioc_ext_qbuf)(struct file *file, void *fh,
>> + struct v4l2_ext_buffer *b);
>> int (*vidioc_expbuf)(struct file *file, void *fh,
>> struct v4l2_exportbuffer *e);
>> int (*vidioc_dqbuf)(struct file *file, void *fh,
>> struct v4l2_buffer *b);
>> + int (*vidioc_ext_dqbuf)(struct file *file, void *fh,
>> + struct v4l2_ext_buffer *b);
>>
>> int (*vidioc_create_bufs)(struct file *file, void *fh,
>> struct v4l2_create_buffers *b);
>> + int (*vidioc_ext_create_bufs)(struct file *file, void *fh,
>> + struct v4l2_ext_create_buffers *b);
>> int (*vidioc_prepare_buf)(struct file *file, void *fh,
>> struct v4l2_buffer *b);
>> + int (*vidioc_ext_prepare_buf)(struct file *file, void *fh,
>> + struct v4l2_ext_buffer *b);
>>
>> int (*vidioc_overlay)(struct file *file, void *fh, unsigned int i);
>> int (*vidioc_g_fbuf)(struct file *file, void *fh,
>> @@ -758,6 +778,12 @@ int v4l2_ext_pix_format_to_format(const struct v4l2_ext_pix_format *e,
>> struct v4l2_format *f,
>> bool mplane_cap, bool strict);
>>
>> +int v4l2_ext_buffer_to_buffer(const struct v4l2_ext_buffer *e,
>> + struct v4l2_buffer *b,
>> + bool mplane_cap);
>> +int v4l2_buffer_to_ext_buffer(const struct v4l2_buffer *b,
>> + struct v4l2_ext_buffer *e);
>> +
>> /*
>> * The user space interpretation of the 'v4l2_event' differs
>> * based on the 'time_t' definition on 32-bit architectures, so
>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
>> index 7123c6a4d9569..334cafdd2be97 100644
>> --- a/include/uapi/linux/videodev2.h
>> +++ b/include/uapi/linux/videodev2.h
>> @@ -996,6 +996,41 @@ struct v4l2_plane {
>> __u32 reserved[11];
>> };
>>
>> +/**
>> + * struct v4l2_ext_plane - extended plane buffer info
>> + * @buffer_length: size of the entire buffer in bytes, should fit
>> + * @offset + @plane_length
>
> Do we actually need this buffer_length at all? We have 3 memory types:
>
> 1) MMAP - here vb2 already knows the buffer size, because it created it.
>
> 2) DMABUF - the DMA-buf kAPI provides the information about buffer size.
>
> 3) USERPTR - this might actually benefit from buffer_length, because there
> are additional alignmnent requirements for the user memory, e.g. the
> offset and size must be cacheline aligned.
>
> Arguably, 1) and 2) are the main usage scenarios, while the user space that
> uses them would have to suffer from added complexity, because of the
> legacy/niche case 3).
>
> Could we make this field valid only for USERPTR?
I think so, make sense, I'll implement this for next version.
>
>> + * @plane_length: size of the plane in bytes.
>> + * @mem_offset: If V4L2_MEMORY_MMAP is used, then it can be a "cookie"
>> + * that should be passed to mmap() called on the video node.
>> + * @userptr: when memory is V4L2_MEMORY_USERPTR, a userspace pointer pointing
>> + * to this plane.
>> + * @dmabuf_fd: when memory is V4L2_MEMORY_DMABUF, a userspace file descriptor
>> + * associated with this plane.
>> + * @offset: offset in the memory buffer where the plane starts.
>> + * @memory: enum v4l2_memory; the method, in which the actual video
>> + * data is passed
>> + * @reserved: extra space reserved for future fields, must be set to 0.
>> + *
>> + *
>> + * Buffers consist of one or more planes, e.g. an YCbCr buffer with two planes
>> + * can have one plane for Y, and another for interleaved CbCr components.
>> + * Each plane can reside in a separate memory buffer, or even in
>> + * a completely separate memory node (e.g. in embedded devices).
>> + */
>> +struct v4l2_ext_plane {
>> + __u32 buffer_length;
>> + __u32 plane_length;
>> + union {
>> + __u32 mem_offset;
>> + __u64 userptr;
>> + __s32 dmabuf_fd;
>> + } m;
>> + __u32 offset;
>> + __u32 memory;
>> + __u32 reserved[4];
>> +};
>
> Don't we also need bytesused? Or would plane_length essentially mean the
> amount of space or payload, depending on the usage context?
In my understanding, plane_length is the max amount of data the plane can
occupy, othersize it can overflow the buffer or mess with another plane
that is in the same buffer on a different offset.
I'm probably wrong, but I don't really see why the payload size is usefull,
unless if we set a plane_legth that is much bigger then the data it can carry,
that can impact performance.
Payload can also be calculated from the format.
I can add it back if it is usefull. Please let me know your thoughts.
>
> Similarly, the original data_offset was useful as a return field, which
> some drivers use to indicate that the beginning of the plane is occupied by
> some header or otherwise irrelevant data, which must be skipped. Would the
> offset field be used for this purpose now?
I didn't add an equivalent of the data_offset, since it seemed to be
unused (please see my comments about this above).
>
>> +
>> /**
>> * struct v4l2_buffer - video buffer info
>> * @index: id number of the buffer
>> @@ -1057,6 +1092,33 @@ struct v4l2_buffer {
>> };
>> };
>>
>> +/**
>> + * struct v4l2_ext_buffer - extended video buffer info
>> + * @index: id number of the buffer
>> + * @type: V4L2_BUF_TYPE_VIDEO_CAPTURE or V4L2_BUF_TYPE_VIDEO_OUTPUT
>> + * @flags: buffer informational flags
>
> nit: The order of comments doesn't match the order of fields in the struct.
Ack.
>
>> + * @field: enum v4l2_field; field order of the image in the buffer
>> + * @timestamp: frame timestamp
>> + * @sequence: sequence count of this frame
>> + * @planes: per-plane buffer information
>> + * @request_fd: fd of the request that this buffer should use
>> + * @reserved: extra space reserved for future fields, must be set to 0
>> + *
>> + * Contains data exchanged by application and driver using one of the Streaming
>> + * I/O methods.
>> + */
>> +struct v4l2_ext_buffer {
>> + __u32 index;
>> + __u32 type;
>> + __u32 field;
>> + __u32 sequence;
>> + __u64 flags;
>> + __u64 timestamp;
>
> What's the unit? How does this play with the other UAPI that the user space
> may use, e.g. clock_gettime() which returns struct timespec?
The unity is nsec:
e->timestamp = b->timestamp.tv_sec * NSEC_PER_SEC +
b->timestamp.tv_usec * NSEC_PER_USEC;
I can clarify in the docs, is this ok?
>
>> + struct v4l2_ext_plane planes[VIDEO_MAX_PLANES];
>> + __s32 request_fd;
>> + __u32 reserved[9];
>> +};
>> +
>> #ifndef __KERNEL__
>> /**
>> * v4l2_timeval_to_ns - Convert timeval to nanoseconds
>> @@ -2523,6 +2585,29 @@ struct v4l2_create_buffers {
>> __u32 reserved[6];
>> };
>>
>> +/**
>> + * struct v4l2_ext_create_buffers - VIDIOC_EXT_CREATE_BUFS argument
>> + * @index: on return, index of the first created buffer
>> + * @count: entry: number of requested buffers,
>> + * return: number of created buffers
>> + * @memory: enum v4l2_memory; buffer memory type
>> + * @capabilities: capabilities of this buffer type.
>> + * @format: frame format, for which buffers are requested
>> + * @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).
>
> Do we need to say that it is ignored here? I'd consider this to be a
> per-flag decision.
flags field was removed from v4l2_create_buffers, so I'm removing it from
v4l2_ext_create_buffers for the same reason.
Thanks,
Helen
>
> Best regards,
> Tomasz
>
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