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SubjectRe: [RFCv4 16/21] v4l2: video_device: support for creating requests
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On 02/20/2018 05:44 AM, Alexandre Courbot wrote:
> Add a new VIDIOC_NEW_REQUEST ioctl, which allows to instanciate requests
> on devices that support the request API. Requests created that way can
> only control the device they originate from, making them suitable for
> simple devices, but not complex pipelines.
>
> Signed-off-by: Alexandre Courbot <acourbot@chromium.org>
> ---
> Documentation/ioctl/ioctl-number.txt | 1 +
> drivers/media/v4l2-core/v4l2-dev.c | 2 ++
> drivers/media/v4l2-core/v4l2-ioctl.c | 25 +++++++++++++++++++++++++
> include/media/v4l2-dev.h | 2 ++
> include/uapi/linux/videodev2.h | 3 +++
> 5 files changed, 33 insertions(+)
>
> diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
> index 6501389d55b9..afdc9ed255b0 100644
> --- a/Documentation/ioctl/ioctl-number.txt
> +++ b/Documentation/ioctl/ioctl-number.txt
> @@ -286,6 +286,7 @@ Code Seq#(hex) Include File Comments
> <mailto:oe@port.de>
> 'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
> '|' 00-7F linux/media.h
> +'|' 80-9F linux/media-request.h
> 0x80 00-1F linux/fb.h
> 0x89 00-06 arch/x86/include/asm/sockios.h
> 0x89 0B-DF linux/sockios.h

This ^^^^ doesn't belong in this patch.

> diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
> index 0301fe426a43..062ebee5bffc 100644
> --- a/drivers/media/v4l2-core/v4l2-dev.c
> +++ b/drivers/media/v4l2-core/v4l2-dev.c
> @@ -559,6 +559,8 @@ static void determine_valid_ioctls(struct video_device *vdev)
> set_bit(_IOC_NR(VIDIOC_TRY_EXT_CTRLS), valid_ioctls);
> if (vdev->ctrl_handler || ops->vidioc_querymenu)
> set_bit(_IOC_NR(VIDIOC_QUERYMENU), valid_ioctls);
> + if (vdev->req_mgr)
> + set_bit(_IOC_NR(VIDIOC_NEW_REQUEST), valid_ioctls);
> SET_VALID_IOCTL(ops, VIDIOC_G_FREQUENCY, vidioc_g_frequency);
> SET_VALID_IOCTL(ops, VIDIOC_S_FREQUENCY, vidioc_s_frequency);
> SET_VALID_IOCTL(ops, VIDIOC_LOG_STATUS, vidioc_log_status);
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index ab4968ea443f..a45fe078f8ae 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -21,6 +21,7 @@
>
> #include <linux/videodev2.h>
>
> +#include <media/media-request.h>
> #include <media/v4l2-common.h>
> #include <media/v4l2-ioctl.h>
> #include <media/v4l2-ctrls.h>
> @@ -842,6 +843,13 @@ static void v4l_print_freq_band(const void *arg, bool write_only)
> p->rangehigh, p->modulation);
> }
>
> +static void vidioc_print_new_request(const void *arg, bool write_only)
> +{
> + const struct media_request_new *new = arg;
> +
> + pr_cont("fd=0x%x\n", new->fd);

I'd use %d since fds are typically shown as signed integers.

> +}
> +
> static void v4l_print_edid(const void *arg, bool write_only)
> {
> const struct v4l2_edid *p = arg;
> @@ -2486,6 +2494,22 @@ static int v4l_enum_freq_bands(const struct v4l2_ioctl_ops *ops,
> return -ENOTTY;
> }
>
> +static int vidioc_new_request(const struct v4l2_ioctl_ops *ops,
> + struct file *file, void *fh, void *arg)
> +{
> +#if IS_ENABLED(CONFIG_MEDIA_REQUEST_API)
> + struct media_request_new *new = arg;
> + struct video_device *vfd = video_devdata(file);
> +
> + if (!vfd->req_mgr)
> + return -ENOTTY;
> +
> + return media_request_ioctl_new(vfd->req_mgr, new);
> +#else
> + return -ENOTTY;
> +#endif
> +}

You don't need the #ifdef's here. media_request_ioctl_new() will be stubbed if
CONFIG_MEDIA_REQUEST_API isn't set.

> +
> struct v4l2_ioctl_info {
> unsigned int ioctl;
> u32 flags;
> @@ -2617,6 +2641,7 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
> IOCTL_INFO_FNC(VIDIOC_ENUM_FREQ_BANDS, v4l_enum_freq_bands, v4l_print_freq_band, 0),
> IOCTL_INFO_FNC(VIDIOC_DBG_G_CHIP_INFO, v4l_dbg_g_chip_info, v4l_print_dbg_chip_info, INFO_FL_CLEAR(v4l2_dbg_chip_info, match)),
> IOCTL_INFO_FNC(VIDIOC_QUERY_EXT_CTRL, v4l_query_ext_ctrl, v4l_print_query_ext_ctrl, INFO_FL_CTRL | INFO_FL_CLEAR(v4l2_query_ext_ctrl, id)),
> + IOCTL_INFO_FNC(VIDIOC_NEW_REQUEST, vidioc_new_request, vidioc_print_new_request, 0),
> };
> #define V4L2_IOCTLS ARRAY_SIZE(v4l2_ioctls)
>
> diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
> index 53f32022fabe..e6c4e10889bc 100644
> --- a/include/media/v4l2-dev.h
> +++ b/include/media/v4l2-dev.h
> @@ -209,6 +209,7 @@ struct v4l2_file_operations {
> * @entity: &struct media_entity
> * @intf_devnode: pointer to &struct media_intf_devnode
> * @pipe: &struct media_pipeline
> + * @req_mgr: request manager to use if this device supports creating requests
> * @fops: pointer to &struct v4l2_file_operations for the video device
> * @device_caps: device capabilities as used in v4l2_capabilities
> * @dev: &struct device for the video device
> @@ -251,6 +252,7 @@ struct video_device
> struct media_intf_devnode *intf_devnode;
> struct media_pipeline pipe;
> #endif
> + struct media_request_mgr *req_mgr;
> const struct v4l2_file_operations *fops;
>
> u32 device_caps;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 91cfe0cbd5c5..35706204e81d 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -63,6 +63,7 @@
> #include <linux/compiler.h>
> #include <linux/ioctl.h>
> #include <linux/types.h>
> +#include <linux/media-request.h>
> #include <linux/v4l2-common.h>
> #include <linux/v4l2-controls.h>
>
> @@ -2407,6 +2408,8 @@ struct v4l2_create_buffers {
>
> #define VIDIOC_QUERY_EXT_CTRL _IOWR('V', 103, struct v4l2_query_ext_ctrl)
>
> +#define VIDIOC_NEW_REQUEST _IOWR('V', 104, struct media_request_new)

Hmm, I probably call this VIDIOC_CREATE_REQUEST (analogous to CREATE_BUFS).
Ditto struct media_create_request and MEDIA_IOC_CREATE_REQUEST.

I'm still not convinced this is the right approach (as opposed to using the media
device node). I plan to dig deeper into the data structures tomorrow morning.

Regards,

Hans

> +
> /* Reminder: when adding new ioctls please add support for them to
> drivers/media/v4l2-core/v4l2-compat-ioctl32.c as well! */
>
>
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