diff mbox

[v3,media] vimc: Virtual Media Controller core, capture and sensor

Message ID 1459974009-20201-1-git-send-email-helen.koike@collabora.co.uk (mailing list archive)
State New, archived
Headers show

Commit Message

Helen Koike April 6, 2016, 8:20 p.m. UTC
From: Helen Fornazier <helen.fornazier@gmail.com>

First version of the Virtual Media Controller.
Add a simple version of the core of the driver, the capture and
sensor nodes in the topology, generating a grey image in a hardcoded
format.

Signed-off-by: Helen Fornazier <helen.fornazier@gmail.com>
---

Changes since v2: update with current media master tree
- Add struct media_pipeline in vimc_cap_device
- Use vb2_v4l2_buffer instead of vb2_buffer
- Typos
- Remove usage of entity->type and use entity->function instead
- Remove fmt argument from queue setup
- Use ktime_get_ns instead of v4l2_get_timestamp
- Iterate over link's list using list_for_each_entry
- Use media_device_{init, cleanup}
- Use entity->use_count to keep track of entities instead of the old
entity->id
- Replace media_entity_init by media_entity_pads_init

 drivers/media/platform/Kconfig             |   2 +
 drivers/media/platform/Makefile            |   1 +
 drivers/media/platform/vimc/Kconfig        |   6 +
 drivers/media/platform/vimc/Makefile       |   3 +
 drivers/media/platform/vimc/vimc-capture.c | 534 ++++++++++++++++++++++++++
 drivers/media/platform/vimc/vimc-capture.h |  28 ++
 drivers/media/platform/vimc/vimc-core.c    | 595 +++++++++++++++++++++++++++++
 drivers/media/platform/vimc/vimc-core.h    |  55 +++
 drivers/media/platform/vimc/vimc-sensor.c  | 277 ++++++++++++++
 drivers/media/platform/vimc/vimc-sensor.h  |  28 ++
 10 files changed, 1529 insertions(+)
 create mode 100644 drivers/media/platform/vimc/Kconfig
 create mode 100644 drivers/media/platform/vimc/Makefile
 create mode 100644 drivers/media/platform/vimc/vimc-capture.c
 create mode 100644 drivers/media/platform/vimc/vimc-capture.h
 create mode 100644 drivers/media/platform/vimc/vimc-core.c
 create mode 100644 drivers/media/platform/vimc/vimc-core.h
 create mode 100644 drivers/media/platform/vimc/vimc-sensor.c
 create mode 100644 drivers/media/platform/vimc/vimc-sensor.h

Comments

Helen Mae Koike Fornazier April 27, 2016, 4:33 p.m. UTC | #1
Hi,

On Wed, Apr 6, 2016 at 5:20 PM, Helen Mae Koike Fornazier
<helen.koike@collabora.co.uk> wrote:
> From: Helen Fornazier <helen.fornazier@gmail.com>
>
> First version of the Virtual Media Controller.
> Add a simple version of the core of the driver, the capture and
> sensor nodes in the topology, generating a grey image in a hardcoded
> format.
>
> Signed-off-by: Helen Fornazier <helen.fornazier@gmail.com>
> ---
>
> Changes since v2: update with current media master tree
> - Add struct media_pipeline in vimc_cap_device
> - Use vb2_v4l2_buffer instead of vb2_buffer
> - Typos
> - Remove usage of entity->type and use entity->function instead
> - Remove fmt argument from queue setup
> - Use ktime_get_ns instead of v4l2_get_timestamp
> - Iterate over link's list using list_for_each_entry
> - Use media_device_{init, cleanup}
> - Use entity->use_count to keep track of entities instead of the old
> entity->id
> - Replace media_entity_init by media_entity_pads_init
>
>  drivers/media/platform/Kconfig             |   2 +
>  drivers/media/platform/Makefile            |   1 +
>  drivers/media/platform/vimc/Kconfig        |   6 +
>  drivers/media/platform/vimc/Makefile       |   3 +
>  drivers/media/platform/vimc/vimc-capture.c | 534 ++++++++++++++++++++++++++
>  drivers/media/platform/vimc/vimc-capture.h |  28 ++
>  drivers/media/platform/vimc/vimc-core.c    | 595 +++++++++++++++++++++++++++++
>  drivers/media/platform/vimc/vimc-core.h    |  55 +++
>  drivers/media/platform/vimc/vimc-sensor.c  | 277 ++++++++++++++
>  drivers/media/platform/vimc/vimc-sensor.h  |  28 ++
>  10 files changed, 1529 insertions(+)
>  create mode 100644 drivers/media/platform/vimc/Kconfig
>  create mode 100644 drivers/media/platform/vimc/Makefile
>  create mode 100644 drivers/media/platform/vimc/vimc-capture.c
>  create mode 100644 drivers/media/platform/vimc/vimc-capture.h
>  create mode 100644 drivers/media/platform/vimc/vimc-core.c
>  create mode 100644 drivers/media/platform/vimc/vimc-core.h
>  create mode 100644 drivers/media/platform/vimc/vimc-sensor.c
>  create mode 100644 drivers/media/platform/vimc/vimc-sensor.h
>
> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> index 201f5c2..14ed03f 100644
> --- a/drivers/media/platform/Kconfig
> +++ b/drivers/media/platform/Kconfig
> @@ -284,6 +284,8 @@ menuconfig V4L_TEST_DRIVERS
>
>  if V4L_TEST_DRIVERS
>
> +source "drivers/media/platform/vimc/Kconfig"
> +
>  source "drivers/media/platform/vivid/Kconfig"
>
>  config VIDEO_VIM2M
> diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
> index bbb7bd1..e4508fe 100644
> --- a/drivers/media/platform/Makefile
> +++ b/drivers/media/platform/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_VIDEO_OMAP3)     += omap3isp/
>
>  obj-$(CONFIG_VIDEO_VIU) += fsl-viu.o
>
> +obj-$(CONFIG_VIDEO_VIMC)               += vimc/
>  obj-$(CONFIG_VIDEO_VIVID)              += vivid/
>  obj-$(CONFIG_VIDEO_VIM2M)              += vim2m.o
>
> diff --git a/drivers/media/platform/vimc/Kconfig b/drivers/media/platform/vimc/Kconfig
> new file mode 100644
> index 0000000..81279f4
> --- /dev/null
> +++ b/drivers/media/platform/vimc/Kconfig
> @@ -0,0 +1,6 @@
> +config VIDEO_VIMC
> +       tristate "Virtual Media Controller Driver (VIMC)"
> +       select VIDEO_V4L2_SUBDEV_API
> +       default n
> +       ---help---
> +         Skeleton driver for Virtual Media Controller
> diff --git a/drivers/media/platform/vimc/Makefile b/drivers/media/platform/vimc/Makefile
> new file mode 100644
> index 0000000..c45195e
> --- /dev/null
> +++ b/drivers/media/platform/vimc/Makefile
> @@ -0,0 +1,3 @@
> +vimc-objs := vimc-core.o vimc-capture.o vimc-sensor.o
> +
> +obj-$(CONFIG_VIDEO_VIMC) += vimc.o
> diff --git a/drivers/media/platform/vimc/vimc-capture.c b/drivers/media/platform/vimc/vimc-capture.c
> new file mode 100644
> index 0000000..3fb8bfe
> --- /dev/null
> +++ b/drivers/media/platform/vimc/vimc-capture.c
> @@ -0,0 +1,534 @@
> +/*
> + * vimc-capture.c Virtual Media Controller Driver
> + *
> + * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <media/videobuf2-core.h>
> +#include <media/videobuf2-vmalloc.h>
> +#include <media/v4l2-ioctl.h>
> +
> +#include "vimc-capture.h"
> +
> +struct vimc_cap_device {
> +       struct vimc_ent_device ved;
> +       struct video_device vdev;
> +       struct v4l2_device *v4l2_dev;
> +       struct device *dev;
> +       struct v4l2_pix_format format;
> +       struct vb2_queue queue;
> +       struct list_head buf_list;
> +       /* NOTE: in a real driver, a spin lock must be used to access the
> +        * queue because the frames are generated from a hardware interruption
> +        * and the isr is not allowed to sleep.
> +        * Even if it is not necessary a spinlock in the vimc driver, we
> +        * use it here as a code reference */
> +       spinlock_t qlock;
> +       struct mutex lock;
> +       u32 sequence;
> +       struct media_pipeline pipe;
> +};
> +
> +struct vimc_cap_buffer {
> +       /*
> +        * vb2_buffer must be the first element
> +        * the videobf2 framework will allocate this struct based on
> +        * buf_struct_size and use the first sizeof(struct vb2_buffer) bytes of
> +        * memory as a vb2_buffer
> +        */
> +       struct vb2_v4l2_buffer vb2;
> +       struct list_head list;
> +};
> +
> +static int vimc_cap_querycap(struct file *file, void *priv,
> +                            struct v4l2_capability *cap)
> +{
> +       struct vimc_cap_device *vcap = video_drvdata(file);
> +
> +       strlcpy(cap->driver, KBUILD_MODNAME, sizeof(cap->driver));
> +       strlcpy(cap->card, KBUILD_MODNAME, sizeof(cap->card));
> +       snprintf(cap->bus_info, sizeof(cap->bus_info),
> +                "platform:%s", vcap->v4l2_dev->name);
> +
> +       cap->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
> +       cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
> +
> +       return 0;
> +}
> +
> +static int vimc_cap_enum_input(struct file *file, void *priv,
> +                              struct v4l2_input *i)
> +{
> +       /* We only have one input */
> +       if (i->index > 0)
> +               return -EINVAL;
> +
> +       i->type = V4L2_INPUT_TYPE_CAMERA;
> +       strlcpy(i->name, "VIMC capture", sizeof(i->name));
> +
> +       return 0;
> +}
> +
> +static int vimc_cap_g_input(struct file *file, void *priv, unsigned int *i)
> +{
> +       /* We only have one input */
> +       *i = 0;
> +       return 0;
> +}
> +
> +static int vimc_cap_s_input(struct file *file, void *priv, unsigned int i)
> +{
> +       /* We only have one input */
> +       return i ? -EINVAL : 0;
> +}
> +
> +static int vimc_cap_g_fmt_vid_cap(struct file *file, void *priv,
> +                                 struct v4l2_format *f)
> +{
> +       struct vimc_cap_device *vcap = video_drvdata(file);
> +
> +       f->fmt.pix = vcap->format;
> +
> +       return 0;
> +}
> +
> +static int vimc_cap_enum_fmt_vid_cap(struct file *file, void *priv,
> +                                    struct v4l2_fmtdesc *f)
> +{
> +       struct vimc_cap_device *vcap = video_drvdata(file);
> +
> +       if (f->index > 0)
> +               return -EINVAL;
> +
> +       /* We only support one format for now */
> +       f->pixelformat = vcap->format.pixelformat;
> +
> +       return 0;
> +}
> +
> +static const struct v4l2_file_operations vimc_cap_fops = {
> +       .owner          = THIS_MODULE,
> +       .open           = v4l2_fh_open,
> +       .release        = vb2_fop_release,
> +       .read           = vb2_fop_read,
> +       .poll           = vb2_fop_poll,
> +       .unlocked_ioctl = video_ioctl2,
> +       .mmap           = vb2_fop_mmap,
> +};
> +
> +static const struct v4l2_ioctl_ops vimc_cap_ioctl_ops = {
> +       .vidioc_querycap = vimc_cap_querycap,
> +
> +       .vidioc_enum_input = vimc_cap_enum_input,
> +       .vidioc_g_input = vimc_cap_g_input,
> +       .vidioc_s_input = vimc_cap_s_input,
> +
> +       .vidioc_g_fmt_vid_cap = vimc_cap_g_fmt_vid_cap,
> +       .vidioc_s_fmt_vid_cap = vimc_cap_g_fmt_vid_cap,
> +       .vidioc_try_fmt_vid_cap = vimc_cap_g_fmt_vid_cap,
> +       .vidioc_enum_fmt_vid_cap = vimc_cap_enum_fmt_vid_cap,
> +
> +       .vidioc_reqbufs = vb2_ioctl_reqbufs,
> +       .vidioc_create_bufs = vb2_ioctl_create_bufs,
> +       .vidioc_querybuf = vb2_ioctl_querybuf,
> +       .vidioc_qbuf = vb2_ioctl_qbuf,
> +       .vidioc_dqbuf = vb2_ioctl_dqbuf,
> +       .vidioc_expbuf = vb2_ioctl_expbuf,
> +       .vidioc_streamon = vb2_ioctl_streamon,
> +       .vidioc_streamoff = vb2_ioctl_streamoff,
> +};
> +
> +static void vimc_cap_return_all_buffers(struct vimc_cap_device *vcap,
> +                                       enum vb2_buffer_state state)
> +{
> +       struct vimc_cap_buffer *vbuf, *node;
> +
> +       spin_lock(&vcap->qlock);
> +
> +       list_for_each_entry_safe(vbuf, node, &vcap->buf_list, list) {
> +               vb2_buffer_done(&vbuf->vb2.vb2_buf, state);
> +               list_del(&vbuf->list);
> +       }
> +
> +       spin_unlock(&vcap->qlock);
> +}
> +
> +static int vimc_cap_pipeline_s_stream(struct vimc_cap_device *vcap, int enable)
> +{
> +       int ret;
> +       struct media_pad *pad;
> +       struct media_entity *entity;
> +       struct v4l2_subdev *sd;
> +
> +       /* Start the stream in the subdevice direct connected */
> +       entity = &vcap->vdev.entity;
> +       pad = media_entity_remote_pad(&entity->pads[0]);
> +
> +       /* If we are not connected to any subdev node, it means there is nothing
> +        * to activate on the pipe (e.g. we can be connected with an input
> +        * device or we are not connected at all)
> +        */
> +       if (pad == NULL || !is_media_entity_v4l2_subdev(pad->entity))
> +               return 0;
> +
> +       entity = pad->entity;
> +       sd = media_entity_to_v4l2_subdev(entity);
> +
> +       ret = v4l2_subdev_call(sd, video, s_stream, enable);
> +       if (ret && ret != -ENOIOCTLCMD)
> +               return ret;
> +
> +       return 0;
> +}
> +
> +static int vimc_cap_start_streaming(struct vb2_queue *vq, unsigned int count)
> +{
> +       struct vimc_cap_device *vcap = vb2_get_drv_priv(vq);
> +       struct media_entity *entity;
> +       int ret;
> +
> +       vcap->sequence = 0;
> +
> +       /* Start the media pipeline */
> +       entity = &vcap->vdev.entity;
> +       ret = media_entity_pipeline_start(entity, &vcap->pipe);
> +       if (ret) {
> +               vimc_cap_return_all_buffers(vcap, VB2_BUF_STATE_QUEUED);
> +               return ret;
> +       }
> +
> +       /* Enable streaming from the pipe */
> +       ret = vimc_cap_pipeline_s_stream(vcap, 1);
> +       if (ret) {
> +               vimc_cap_return_all_buffers(vcap, VB2_BUF_STATE_QUEUED);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +/*
> + * Stop the stream engine. Any remaining buffers in the stream queue are
> + * dequeued and passed on to the vb2 framework marked as STATE_ERROR.
> + */
> +static void vimc_cap_stop_streaming(struct vb2_queue *vq)
> +{
> +       struct vimc_cap_device *vcap = vb2_get_drv_priv(vq);
> +
> +       /* Disable streaming from the pipe */
> +       vimc_cap_pipeline_s_stream(vcap, 0);
> +
> +       /* Stop the media pipeline */
> +       media_entity_pipeline_stop(&vcap->vdev.entity);
> +
> +       /* Release all active buffers */
> +       vimc_cap_return_all_buffers(vcap, VB2_BUF_STATE_ERROR);
> +}
> +
> +static void vimc_cap_buf_queue(struct vb2_buffer *vb2_buf)
> +{
> +       struct vimc_cap_device *vcap = vb2_get_drv_priv(vb2_buf->vb2_queue);
> +       struct vimc_cap_buffer *buf = container_of(vb2_buf,
> +                                       struct vimc_cap_buffer, vb2.vb2_buf);
> +
> +       /* If the buffer doesn't have enough size, mark it as error */
> +       if (vb2_buf->planes[0].length < vcap->format.sizeimage) {
> +               vb2_buffer_done(vb2_buf, VB2_BUF_STATE_ERROR);
> +               return;
> +       }
> +
> +       spin_lock(&vcap->qlock);
> +
> +       list_add_tail(&buf->list, &vcap->buf_list);
> +
> +       spin_unlock(&vcap->qlock);
> +}
> +
> +static int vimc_cap_queue_setup(struct vb2_queue *vq,
> +                               unsigned int *nbuffers, unsigned int *nplanes,
> +                               unsigned int sizes[], void *alloc_ctxs[])
> +{
> +       struct vimc_cap_device *vcap = vb2_get_drv_priv(vq);
> +
> +       /* We don't support multiplanes for now */
> +       *nplanes = 1;
> +       sizes[0] = vcap->format.sizeimage;
> +
> +       return 0;
> +}
> +
> +static const struct vb2_ops vimc_cap_qops = {
> +       .start_streaming        = vimc_cap_start_streaming,
> +       .stop_streaming         = vimc_cap_stop_streaming,
> +       .buf_queue              = vimc_cap_buf_queue,
> +       .queue_setup            = vimc_cap_queue_setup,
> +       /*
> +        * Since q->lock is set we can use the standard
> +        * vb2_ops_wait_prepare/finish helper functions.
> +        */
> +       .wait_prepare           = vb2_ops_wait_prepare,
> +       .wait_finish            = vb2_ops_wait_finish,
> +};
> +
> +/* NOTE: this function is a copy of v4l2_subdev_link_validate_get_format
> + * maybe the v4l2 function should be public */
> +static int vimc_cap_v4l2_subdev_link_validate_get_format(struct media_pad *pad,
> +                                               struct v4l2_subdev_format *fmt)
> +{
> +       struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(pad->entity);
> +
> +       fmt->which = V4L2_SUBDEV_FORMAT_ACTIVE;
> +       fmt->pad = pad->index;
> +       return v4l2_subdev_call(sd, pad, get_fmt, NULL, fmt);
> +}
> +
> +static int vimc_cap_link_validate(struct media_link *link)
> +{
> +       struct v4l2_subdev_format source_fmt;
> +       struct v4l2_pix_format *sink_fmt;
> +       struct vimc_cap_device *vcap;
> +       const struct vimc_pix_map *vpix;
> +       int ret;
> +
> +       /* Retrieve the video capture device */
> +       vcap = container_of(link->sink->entity,
> +                           struct vimc_cap_device, vdev.entity);
> +
> +       /* If the connected node is not a subdevice type
> +        * then it's a raw node from vimc-core, ignore the link for now
> +        * TODO: remove this when there are no more raw nodes in the
> +        * core and return error instead */
> +       if (!is_media_entity_v4l2_subdev(link->source->entity))
> +               return 0;
> +
> +       /* Get the the format of the video device */
> +       sink_fmt = &vcap->format;
> +
> +       /* Get the the format of the subdev */
> +       ret = vimc_cap_v4l2_subdev_link_validate_get_format(link->source,
> +                                                           &source_fmt);
> +       if (ret)
> +               return ret;
> +
> +       dev_dbg(vcap->dev,
> +               "cap: %s: link validate formats src:%dx%d %d sink:%dx%d %d\n",
> +               vcap->vdev.name,
> +               source_fmt.format.width, source_fmt.format.height,
> +               source_fmt.format.code,
> +               sink_fmt->width, sink_fmt->height,
> +               sink_fmt->pixelformat);
> +
> +       /* Validate the format */
> +
> +       vpix = vimc_pix_map_by_pixelformat(sink_fmt->pixelformat);
> +       if (!vpix)
> +               return -EINVAL;
> +
> +       /* The width, height and code must match. */
> +       if (source_fmt.format.width != sink_fmt->width
> +           || source_fmt.format.height != sink_fmt->height
> +           || vpix->code != source_fmt.format.code)
> +               return -EINVAL;
> +
> +       /* The field order must match, or the sink field order must be NONE
> +        * to support interlaced hardware connected to bridges that support
> +        * progressive formats only.
> +        */
> +       if (source_fmt.format.field != sink_fmt->field &&
> +           sink_fmt->field != V4L2_FIELD_NONE)
> +               return -EINVAL;
> +
> +       return 0;
> +}
> +
> +static const struct media_entity_operations vimc_cap_mops = {
> +       .link_validate          = vimc_cap_link_validate,
> +};
> +
> +static void vimc_cap_destroy(struct vimc_ent_device *ved)
> +{
> +       struct vimc_cap_device *vcap = container_of(ved, struct vimc_cap_device,
> +                                                   ved);
> +
> +       vb2_queue_release(&vcap->queue);
> +       media_entity_cleanup(ved->ent);
> +       video_unregister_device(&vcap->vdev);
> +       vimc_pads_cleanup(vcap->ved.pads);
> +       kfree(vcap);
> +}
> +
> +static void vimc_cap_process_frame(struct vimc_ent_device *ved,
> +                                  struct media_pad *sink, const void *frame)
> +{
> +       struct vimc_cap_device *vcap = container_of(ved, struct vimc_cap_device,
> +                                                   ved);
> +       struct vimc_cap_buffer *vimc_buf;
> +       void *vbuf;
> +
> +       /* If the stream in this node is not active, just return */
> +       mutex_lock(&vcap->lock);
> +       if (!vb2_is_busy(&vcap->queue)) {
> +               mutex_unlock(&vcap->lock);
> +               return;
> +       }
> +       mutex_unlock(&vcap->lock);
> +
> +       spin_lock(&vcap->qlock);
> +
> +       /* Get the first entry of the list */
> +       vimc_buf = list_first_entry_or_null(&vcap->buf_list,
> +                                           typeof(*vimc_buf), list);
> +       if (!vimc_buf) {
> +               spin_unlock(&vcap->qlock);
> +               return;
> +       }
> +
> +       /* Remove this entry from the list */
> +       list_del(&vimc_buf->list);
> +
> +       spin_unlock(&vcap->qlock);
> +
> +       /* Fill the buffer */
> +       vimc_buf->vb2.vb2_buf.timestamp = ktime_get_ns();
> +       vimc_buf->vb2.sequence = vcap->sequence++;
> +       vimc_buf->vb2.field = vcap->format.field;
> +
> +       vbuf = vb2_plane_vaddr(&vimc_buf->vb2.vb2_buf, 0);
> +
> +       memcpy(vbuf, frame, vcap->format.sizeimage);
> +
> +       /* Set it as ready */
> +       vb2_set_plane_payload(&vimc_buf->vb2.vb2_buf, 0,
> +                             vcap->format.sizeimage);
> +       vb2_buffer_done(&vimc_buf->vb2.vb2_buf, VB2_BUF_STATE_DONE);
> +}
> +
> +struct vimc_ent_device *vimc_cap_create(struct v4l2_device *v4l2_dev,
> +                                       const char *const name,
> +                                       u16 num_pads,
> +                                       const unsigned long *pads_flag)
> +{
> +       int ret;
> +       struct vb2_queue *q;
> +       struct video_device *vdev;
> +       struct vimc_cap_device *vcap;
> +       const struct vimc_pix_map *vpix;
> +
> +       if (!v4l2_dev || !v4l2_dev->dev || !name || (num_pads && !pads_flag))
> +               return ERR_PTR(-EINVAL);
> +
> +       /* Allocate the vimc_cap_device struct */
> +       vcap = kzalloc(sizeof(*vcap), GFP_KERNEL);
> +       if (!vcap)
> +               return ERR_PTR(-ENOMEM);
> +
> +       /* Link the vimc_cap_device struct with v4l2 and dev parent */
> +       vcap->v4l2_dev = v4l2_dev;
> +       vcap->dev = v4l2_dev->dev;
> +
> +       /* Allocate the pads */
> +       vcap->ved.pads = vimc_pads_init(num_pads, pads_flag);
> +       if (IS_ERR(vcap->ved.pads)) {
> +               ret = PTR_ERR(vcap->ved.pads);
> +               goto err_free_vcap;
> +       }
> +
> +       /* Initialize the media entity */
> +       vcap->vdev.entity.name = name;
> +       vcap->vdev.entity.function = MEDIA_ENT_F_IO_V4L;
> +       ret = media_entity_pads_init(&vcap->vdev.entity,
> +                                    num_pads, vcap->ved.pads);
> +       if (ret)
> +               goto err_clean_pads;
> +
> +       /* Initialize the lock */
> +       mutex_init(&vcap->lock);
> +
> +       /* Initialize the vb2 queue */
> +       q = &vcap->queue;
> +       q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> +       q->io_modes = VB2_MMAP | VB2_DMABUF;
> +       q->drv_priv = vcap;
> +       q->buf_struct_size = sizeof(struct vimc_cap_buffer);
> +       q->ops = &vimc_cap_qops;
> +       q->mem_ops = &vb2_vmalloc_memops;
> +       q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> +       q->min_buffers_needed = 2;
> +       q->lock = &vcap->lock;
> +
> +       ret = vb2_queue_init(q);
> +       if (ret) {
> +               dev_err(vcap->dev,
> +                       "vb2 queue init failed (err=%d)\n", ret);
> +               goto err_clean_m_ent;
> +       }
> +
> +       /* Initialize buffer list and its lock */
> +       INIT_LIST_HEAD(&vcap->buf_list);
> +       spin_lock_init(&vcap->qlock);
> +
> +       /* Set the frame format (this is hardcoded for now) */
> +       vcap->format.width = 640;
> +       vcap->format.height = 480;
> +       vcap->format.pixelformat = V4L2_PIX_FMT_RGB24;
> +       vcap->format.field = V4L2_FIELD_NONE;
> +       vcap->format.colorspace = V4L2_COLORSPACE_SRGB;
> +
> +       vpix = vimc_pix_map_by_pixelformat(vcap->format.pixelformat);
> +       /* This should never be NULL, as we won't allow any format
> +        * other then the ones in the vimc_pix_map_list table */
> +       BUG_ON(!vpix);
> +
> +       vcap->format.bytesperline = vcap->format.width * vpix->bpp;
> +       vcap->format.sizeimage = vcap->format.bytesperline * vcap->format.height;
> +
> +       /* Fill the vimc_ent_device struct */
> +       vcap->ved.destroy = vimc_cap_destroy;
> +       vcap->ved.ent = &vcap->vdev.entity;
> +       vcap->ved.process_frame = vimc_cap_process_frame;
> +
> +       /* Initialize the video_device struct */
> +       vdev = &vcap->vdev;
> +       vdev->entity.ops = &vimc_cap_mops;
> +       vdev->release = video_device_release_empty;
> +       vdev->fops = &vimc_cap_fops;
> +       vdev->ioctl_ops = &vimc_cap_ioctl_ops;
> +       vdev->lock = &vcap->lock;
> +       vdev->queue = q;
> +       vdev->v4l2_dev = vcap->v4l2_dev;
> +       vdev->vfl_dir = VFL_DIR_RX;
> +       strlcpy(vdev->name, name, sizeof(vdev->name));
> +       video_set_drvdata(vdev, vcap);
> +
> +       /* Register the video_device with the v4l2 and the media framework */
> +       ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
> +       if (ret) {
> +               dev_err(vcap->dev,
> +                       "video register failed (err=%d)\n", ret);
> +               goto err_release_queue;
> +       }
> +
> +       return &vcap->ved;
> +
> +err_release_queue:
> +       vb2_queue_release(q);
> +err_clean_m_ent:
> +       media_entity_cleanup(&vcap->vdev.entity);
> +err_clean_pads:
> +       vimc_pads_cleanup(vcap->ved.pads);
> +err_free_vcap:
> +       kfree(vcap);
> +
> +       return ERR_PTR(ret);
> +}
> diff --git a/drivers/media/platform/vimc/vimc-capture.h b/drivers/media/platform/vimc/vimc-capture.h
> new file mode 100644
> index 0000000..c52781a
> --- /dev/null
> +++ b/drivers/media/platform/vimc/vimc-capture.h
> @@ -0,0 +1,28 @@
> +/*
> + * vimc-capture.h Virtual Media Controller Driver
> + *
> + * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef _VIMC_CAPTURE_H_
> +#define _VIMC_CAPTURE_H_
> +
> +#include "vimc-core.h"
> +
> +struct vimc_ent_device *vimc_cap_create(struct v4l2_device *v4l2_dev,
> +                                       const char *const name,
> +                                       u16 num_pads,
> +                                       const unsigned long *pads_flag);
> +
> +#endif
> diff --git a/drivers/media/platform/vimc/vimc-core.c b/drivers/media/platform/vimc/vimc-core.c
> new file mode 100644
> index 0000000..04c5297
> --- /dev/null
> +++ b/drivers/media/platform/vimc/vimc-core.c
> @@ -0,0 +1,595 @@
> +/*
> + * vimc-core.c Virtual Media Controller Driver
> + *
> + * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <media/media-device.h>
> +#include <media/v4l2-device.h>
> +
> +#include "vimc-capture.h"
> +#include "vimc-core.h"
> +#include "vimc-sensor.h"
> +
> +#define VIMC_PDEV_NAME "vimc"
> +#define VIMC_MDEV_MODEL_NAME "VIMC MDEV"
> +
> +#define VIMC_ENT_LINK(src, srcpad, sink, sinkpad, link_flags) {        \
> +       .src_ent = src,                                         \
> +       .src_pad = srcpad,                                      \
> +       .sink_ent = sink,                                       \
> +       .sink_pad = sinkpad,                                    \
> +       .flags = link_flags,                                    \
> +}
> +
> +#define VIMC_PIX_MAP(_code, _bpp, _pixelformat) {      \
> +       .code = _code,                                  \
> +       .pixelformat = _pixelformat,                    \
> +       .bpp = _bpp,                                    \
> +}
> +
> +struct vimc_device {
> +       /* The pipeline configuration
> +        * (filled before calling vimc_device_register) */
> +       const struct vimc_pipeline_config *pipe_cfg;
> +
> +       /* The Associated media_device parent */
> +       struct media_device mdev;
> +
> +       /* Internal v4l2 parent device*/
> +       struct v4l2_device v4l2_dev;
> +
> +       /* Internal topology */
> +       struct vimc_ent_device **ved;
> +};
> +
> +/**
> + * enum vimc_ent_node - Select the functionality of a node in the topology
> + * @VIMC_ENT_NODE_SENSOR:      A node of type SENSOR simulates a camera sensor
> + *                             generating internal images in bayer format and
> + *                             propagating those images through the pipeline
> + * @VIMC_ENT_NODE_CAPTURE:     A node of type CAPTURE is a v4l2 video_device
> + *                             that exposes the received image from the
> + *                             pipeline to the user space
> + * @VIMC_ENT_NODE_INPUT:       A node of type INPUT is a v4l2 video_device that
> + *                             receives images from the user space and
> + *                             propagates them through the pipeline
> + * @VIMC_ENT_NODE_DEBAYER:     A node type DEBAYER expects to receive a frame
> + *                             in bayer format converts it to RGB
> + * @VIMC_ENT_NODE_SCALER:      A node of type SCALER scales the received image
> + *                             by a given multiplier
> + *
> + * This enum is used in the entity configuration struct to allow the definition
> + * of a custom topology specifying the role of each node on it.
> + */
> +enum vimc_ent_node {
> +       VIMC_ENT_NODE_SENSOR,
> +       VIMC_ENT_NODE_CAPTURE,
> +       VIMC_ENT_NODE_INPUT,
> +       VIMC_ENT_NODE_DEBAYER,
> +       VIMC_ENT_NODE_SCALER,
> +};
> +
> +/* Structure which describes individual configuration for each entity */
> +struct vimc_ent_config {
> +       const char *name;
> +       size_t pads_qty;
> +       const unsigned long *pads_flag;
> +       enum vimc_ent_node node;
> +};
> +
> +/* Structure which describes links between entities */
> +struct vimc_ent_link {
> +       unsigned int src_ent;
> +       u16 src_pad;
> +       unsigned int sink_ent;
> +       u16 sink_pad;
> +       u32 flags;
> +};
> +
> +/* Structure which describes the whole topology */
> +struct vimc_pipeline_config {
> +       const struct vimc_ent_config *ents;
> +       size_t num_ents;
> +       const struct vimc_ent_link *links;
> +       size_t num_links;
> +};
> +
> +/* --------------------------------------------------------------------------
> + * Topology Configuration
> + */
> +
> +static const struct vimc_ent_config ent_config[] = {
> +       {
> +               .name = "Sensor A",
> +               .pads_qty = 1,
> +               .pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SOURCE},
> +               .node = VIMC_ENT_NODE_SENSOR,
> +       },
> +       {
> +               .name = "Sensor B",
> +               .pads_qty = 1,
> +               .pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SOURCE},
> +               .node = VIMC_ENT_NODE_SENSOR,
> +       },
> +       {
> +               .name = "Debayer A",
> +               .pads_qty = 2,
> +               .pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK,
> +                                                    MEDIA_PAD_FL_SOURCE},
> +               .node = VIMC_ENT_NODE_DEBAYER,
> +       },
> +       {
> +               .name = "Debayer B",
> +               .pads_qty = 2,
> +               .pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK,
> +                                                    MEDIA_PAD_FL_SOURCE},
> +               .node = VIMC_ENT_NODE_DEBAYER,
> +       },
> +       {
> +               .name = "Raw Capture 0",
> +               .pads_qty = 1,
> +               .pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK},
> +               .node = VIMC_ENT_NODE_CAPTURE,
> +       },
> +       {
> +               .name = "Raw Capture 1",
> +               .pads_qty = 1,
> +               .pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK},
> +               .node = VIMC_ENT_NODE_CAPTURE,
> +       },
> +       {
> +               .name = "RGB/YUV Input",
> +               .pads_qty = 1,
> +               .pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SOURCE},
> +               .node = VIMC_ENT_NODE_INPUT,
> +       },
> +       {
> +               .name = "Scaler",
> +               .pads_qty = 2,
> +               .pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK,
> +                                                    MEDIA_PAD_FL_SOURCE},
> +               .node = VIMC_ENT_NODE_SCALER,
> +       },
> +       {
> +               .name = "RGB/YUV Capture",
> +               .pads_qty = 1,
> +               .pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK},
> +               .node = VIMC_ENT_NODE_CAPTURE,
> +       },
> +};
> +
> +static const struct vimc_ent_link ent_links[] = {
> +       /* Link: Sensor A (Pad 0)->(Pad 0) Debayer A */
> +       VIMC_ENT_LINK(0, 0, 2, 0, MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
> +       /* Link: Sensor A (Pad 0)->(Pad 0) Raw Capture 0 */
> +       VIMC_ENT_LINK(0, 0, 4, 0, MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
> +       /* Link: Sensor B (Pad 0)->(Pad 0) Debayer B */
> +       VIMC_ENT_LINK(1, 0, 3, 0, MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
> +       /* Link: Sensor B (Pad 0)->(Pad 0) Raw Capture 1 */
> +       VIMC_ENT_LINK(1, 0, 5, 0, MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
> +       /* Link: Debayer A (Pad 1)->(Pad 0) Scaler */
> +       VIMC_ENT_LINK(2, 1, 7, 0, MEDIA_LNK_FL_ENABLED),
> +       /* Link: Debayer B (Pad 1)->(Pad 0) Scaler */
> +       VIMC_ENT_LINK(3, 1, 7, 0, 0),
> +       /* Link: RGB/YUV Input (Pad 0)->(Pad 0) Scaler */
> +       VIMC_ENT_LINK(6, 0, 7, 0, 0),
> +       /* Link: Scaler (Pad 1)->(Pad 0) RGB/YUV Capture */
> +       VIMC_ENT_LINK(7, 1, 8, 0, MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
> +};
> +
> +static const struct vimc_pipeline_config pipe_cfg = {
> +       .ents           = ent_config,
> +       .num_ents       = ARRAY_SIZE(ent_config),
> +       .links          = ent_links,
> +       .num_links      = ARRAY_SIZE(ent_links)
> +};
> +
> +/* -------------------------------------------------------------------------- */
> +
> +static void vimc_dev_release(struct device *dev)
> +{}
> +
> +static struct platform_device vimc_pdev = {
> +       .name           = VIMC_PDEV_NAME,
> +       .dev.release    = vimc_dev_release,
> +};
> +
> +const struct vimc_pix_map vimc_pix_map_list[] = {
> +       /* TODO: add all missing formats */
> +
> +       /* RGB formats */
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_BGR888_1X24, 3, V4L2_PIX_FMT_BGR24),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_RGB888_1X24, 3, V4L2_PIX_FMT_RGB24),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_ARGB8888_1X32, 4, V4L2_PIX_FMT_ARGB32),
> +
> +       /* Bayer formats */
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SBGGR8_1X8, 1, V4L2_PIX_FMT_SBGGR8),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SGBRG8_1X8, 1, V4L2_PIX_FMT_SGBRG8),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SGRBG8_1X8, 1, V4L2_PIX_FMT_SGRBG8),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SRGGB8_1X8, 1, V4L2_PIX_FMT_SRGGB8),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SBGGR10_1X10, 2, V4L2_PIX_FMT_SBGGR10),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SGBRG10_1X10, 2, V4L2_PIX_FMT_SGBRG10),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SGRBG10_1X10, 2, V4L2_PIX_FMT_SGRBG10),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SRGGB10_1X10, 2, V4L2_PIX_FMT_SRGGB10),
> +       /* 10bit raw bayer a-law compressed to 8 bits */
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SBGGR10_ALAW8_1X8, 1, V4L2_PIX_FMT_SBGGR10ALAW8),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SGBRG10_ALAW8_1X8, 1, V4L2_PIX_FMT_SGBRG10ALAW8),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SGRBG10_ALAW8_1X8, 1, V4L2_PIX_FMT_SGRBG10ALAW8),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SRGGB10_ALAW8_1X8, 1, V4L2_PIX_FMT_SRGGB10ALAW8),
> +       /* 10bit raw bayer DPCM compressed to 8 bits */
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SBGGR10_DPCM8_1X8, 1, V4L2_PIX_FMT_SBGGR10DPCM8),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SGBRG10_DPCM8_1X8, 1, V4L2_PIX_FMT_SGBRG10DPCM8),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SGRBG10_DPCM8_1X8, 1, V4L2_PIX_FMT_SGRBG10DPCM8),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SRGGB10_DPCM8_1X8, 1, V4L2_PIX_FMT_SRGGB10DPCM8),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SBGGR12_1X12, 2, V4L2_PIX_FMT_SBGGR12),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SGBRG12_1X12, 2, V4L2_PIX_FMT_SGBRG12),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SGRBG12_1X12, 2, V4L2_PIX_FMT_SGRBG12),
> +       VIMC_PIX_MAP(MEDIA_BUS_FMT_SRGGB12_1X12, 2, V4L2_PIX_FMT_SRGGB12),
> +
> +       /* End */
> +       {0, 0, 0}
> +};
> +
> +const struct vimc_pix_map *vimc_pix_map_by_code(u32 code)
> +{
> +       unsigned int i;
> +
> +       for (i = 0; vimc_pix_map_list[i].bpp; i++) {
> +               if (vimc_pix_map_list[i].code == code)
> +                       return &vimc_pix_map_list[i];
> +       }
> +       return NULL;
> +}
> +
> +const struct vimc_pix_map *vimc_pix_map_by_pixelformat(u32 pixelformat)
> +{
> +       unsigned int i;
> +
> +       for (i = 0; vimc_pix_map_list[i].bpp; i++) {
> +               if (vimc_pix_map_list[i].pixelformat == pixelformat)
> +                       return &vimc_pix_map_list[i];
> +       }
> +       return NULL;
> +}
> +
> +int vimc_propagate_frame(struct device *dev,
> +                        struct media_pad *src, const void *frame)
> +{
> +       struct media_link *link;
> +       struct vimc_device *vimc = dev_get_drvdata(dev);
> +
> +       if (!(src->flags & MEDIA_PAD_FL_SOURCE))
> +               return -EINVAL;
> +
> +       /* Send this frame to all sink pads that are direct linked */
> +       list_for_each_entry(link, &src->entity->links, list) {
> +               if (link->source == src &&
> +                   (link->flags & MEDIA_LNK_FL_ENABLED)) {
> +                       struct vimc_ent_device *ved;
> +
> +                       ved = vimc->ved[link->sink->entity->use_count];
> +                       if (ved && ved->process_frame)
> +                               ved->process_frame(ved, link->sink, frame);
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +static void vimc_device_unregister(struct vimc_device *vimc)
> +{
> +       unsigned int i;
> +
> +       v4l2_device_unregister(&vimc->v4l2_dev);
> +
> +       media_device_unregister(&vimc->mdev);
> +       media_device_cleanup(&vimc->mdev);
> +
> +       /* Cleanup (only initialized) entities */
> +       for (i = 0; i < vimc->pipe_cfg->num_ents; i++) {
> +               if (vimc->ved[i] && vimc->ved[i]->destroy)
> +                       vimc->ved[i]->destroy(vimc->ved[i]);
> +
> +               vimc->ved[i] = NULL;
> +       }
> +}
> +
> +/* Helper function to allocate and initialize pads */
> +struct media_pad *vimc_pads_init(u16 num_pads, const unsigned long *pads_flag)
> +{
> +       unsigned int i;
> +       struct media_pad *pads;
> +
> +       /* Allocate memory for the pads */
> +       pads = kcalloc(num_pads, sizeof(*pads), GFP_KERNEL);
> +       if (!pads)
> +               return ERR_PTR(-ENOMEM);
> +
> +       /* Initialize the pads */
> +       for (i = 0; i < num_pads; i++) {
> +               pads[i].index = i;
> +               pads[i].flags = pads_flag[i];
> +       }
> +
> +       return pads;
> +}
> +
> +/* TODO: remove this function when all the
> + * entities specific code are implemented */
> +static void vimc_raw_destroy(struct vimc_ent_device *ved)
> +{
> +       media_entity_cleanup(ved->ent);
> +
> +       vimc_pads_cleanup(ved->pads);
> +
> +       kfree(ved->ent);
> +
> +       kfree(ved);
> +}
> +
> +/* TODO: remove this function when all the
> + * entities specific code are implemented */
> +static struct vimc_ent_device *vimc_raw_create(struct v4l2_device *v4l2_dev,
> +                                              const char *const name,
> +                                              u16 num_pads,
> +                                              const unsigned long *pads_flag)
> +{
> +       int ret;
> +       struct vimc_ent_device *ved;
> +
> +       /* Allocate the main ved struct */
> +       ved = kzalloc(sizeof(*ved), GFP_KERNEL);
> +       if (!ved)
> +               return ERR_PTR(-ENOMEM);
> +
> +       /* Allocate the media entity */
> +       ved->ent = kzalloc(sizeof(*ved->ent), GFP_KERNEL);
> +       if (!ved->ent) {
> +               ret = -ENOMEM;
> +               goto err_free_ved;
> +       }
> +
> +       /* Allocate the pads */
> +       ved->pads = vimc_pads_init(num_pads, pads_flag);
> +       if (IS_ERR(ved->pads)) {
> +               ret = PTR_ERR(ved->pads);
> +               goto err_free_ent;
> +       }
> +
> +       /* Initialize the media entity */
> +       ved->ent->name = name;
> +       ved->ent->function = MEDIA_ENT_F_IO_V4L;
> +       ret = media_entity_pads_init(ved->ent, num_pads, ved->pads);
> +       if (ret)
> +               goto err_cleanup_pads;
> +
> +       /* Register the media entity */
> +       ret = media_device_register_entity(v4l2_dev->mdev, ved->ent);
> +       if (ret)
> +               goto err_cleanup_entity;
> +
> +       /* Fill out the destroy function and return */
> +       ved->destroy = vimc_raw_destroy;
> +       return ved;
> +
> +err_cleanup_entity:
> +       media_entity_cleanup(ved->ent);
> +err_cleanup_pads:
> +       vimc_pads_cleanup(ved->pads);
> +err_free_ent:
> +       kfree(ved->ent);
> +err_free_ved:
> +       kfree(ved);
> +
> +       return ERR_PTR(ret);
> +}
> +
> +static int vimc_device_register(struct vimc_device *vimc)
> +{
> +       unsigned int i;
> +       int ret = 0;
> +
> +       /* Allocate memory for the vimc_ent_devices pointers */
> +       vimc->ved = devm_kcalloc(vimc->mdev.dev, vimc->pipe_cfg->num_ents,
> +                                sizeof(*vimc->ved), GFP_KERNEL);
> +       if (!vimc->ved)
> +               return -ENOMEM;
> +
> +       /* Register the media device */
> +       ret = media_device_register(&vimc->mdev);
> +       if (ret) {
> +               dev_err(vimc->mdev.dev,
> +                       "media device register failed (err=%d)\n", ret);
> +               return ret;
> +       }
> +
> +       /* Link the media device within the v4l2_device */
> +       vimc->v4l2_dev.mdev = &vimc->mdev;
> +
> +       /* Register the v4l2 struct */
> +       ret = v4l2_device_register(vimc->mdev.dev, &vimc->v4l2_dev);
> +       if (ret) {
> +               dev_err(vimc->mdev.dev,
> +                       "v4l2 device register failed (err=%d)\n", ret);
> +               return ret;
> +       }
> +
> +       /* Initialize entities */
> +       for (i = 0; i < vimc->pipe_cfg->num_ents; i++) {
> +               struct vimc_ent_device *(*create_func)(struct v4l2_device *,
> +                                                      const char *const,
> +                                                      u16,
> +                                                      const unsigned long *);
> +
> +               /* Register the specific node */
> +               switch (vimc->pipe_cfg->ents[i].node) {
> +               case VIMC_ENT_NODE_SENSOR:
> +                       create_func = vimc_sen_create;
> +                       break;
> +
> +               case VIMC_ENT_NODE_CAPTURE:
> +                       create_func = vimc_cap_create;
> +                       break;
> +
> +               /* TODO: Instantiate the specific topology node */
> +               case VIMC_ENT_NODE_INPUT:
> +               case VIMC_ENT_NODE_DEBAYER:
> +               case VIMC_ENT_NODE_SCALER:
> +               default:
> +                       /* TODO: remove this when all the entities specific
> +                        * code are implemented */
> +                       create_func = vimc_raw_create;
> +                       break;
> +               }
> +
> +               vimc->ved[i] = create_func(&vimc->v4l2_dev,
> +                                          vimc->pipe_cfg->ents[i].name,
> +                                          vimc->pipe_cfg->ents[i].pads_qty,
> +                                          vimc->pipe_cfg->ents[i].pads_flag);
> +               if (IS_ERR(vimc->ved[i])) {
> +                       ret = PTR_ERR(vimc->ved[i]);
> +                       vimc->ved[i] = NULL;
> +                       goto err;
> +               }
> +
> +               /* Set use_count to keep track of the ved structure */
> +               vimc->ved[i]->ent->use_count = i;
> +       }
> +
> +       /* Initialize the links between entities */
> +       for (i = 0; i < vimc->pipe_cfg->num_links; i++) {
> +               const struct vimc_ent_link *link = &vimc->pipe_cfg->links[i];
> +
> +               ret = media_create_pad_link(vimc->ved[link->src_ent]->ent,
> +                                           link->src_pad,
> +                                           vimc->ved[link->sink_ent]->ent,
> +                                           link->sink_pad,
> +                                           link->flags);
> +               if (ret)
> +                       goto err;
> +       }
> +
> +       /* Expose all subdev's nodes*/
> +       ret = v4l2_device_register_subdev_nodes(&vimc->v4l2_dev);
> +       if (ret) {
> +               dev_err(vimc->mdev.dev,
> +                       "vimc subdev nodes registration failed (err=%d)\n", ret);
> +               goto err;
> +       }
> +
> +       return 0;
> +
> +err:
> +       /* Destroy de so far created topology */
> +       vimc_device_unregister(vimc);
> +
> +       return ret;
> +}
> +
> +static int vimc_probe(struct platform_device *pdev)
> +{
> +       struct vimc_device *vimc;
> +       int ret;
> +
> +       /* Prepare the vimc topology structure */
> +
> +       /* Allocate memory for the vimc structure */
> +       vimc = devm_kzalloc(&pdev->dev, sizeof(*vimc), GFP_KERNEL);
> +       if (!vimc)
> +               return -ENOMEM;
> +
> +       /* Set the pipeline configuration struct */
> +       vimc->pipe_cfg = &pipe_cfg;
> +
> +       /* Initialize media device */
> +       strlcpy(vimc->mdev.model, VIMC_MDEV_MODEL_NAME,
> +               sizeof(vimc->mdev.model));
> +       vimc->mdev.dev = &pdev->dev;
> +       media_device_init(&vimc->mdev);
> +
> +       /* Create vimc topology */
> +       ret = vimc_device_register(vimc);
> +       if (ret) {
> +               dev_err(vimc->mdev.dev,
> +                       "vimc device registration failed (err=%d)\n", ret);
> +               return ret;
> +       }
> +
> +       /* Link the topology object with the platform device object */
> +       platform_set_drvdata(pdev, vimc);
> +
> +       return 0;
> +}
> +
> +static int vimc_remove(struct platform_device *pdev)
> +{
> +       struct vimc_device *vimc;
> +
> +       /* Get the topology object linked with the platform device object */
> +       vimc = platform_get_drvdata(pdev);
> +
> +       /* Destroy all the topology */
> +       vimc_device_unregister(vimc);
> +
> +       return 0;
> +}
> +
> +static struct platform_driver vimc_pdrv = {
> +       .probe          = vimc_probe,
> +       .remove         = vimc_remove,
> +       .driver         = {
> +               .name   = VIMC_PDEV_NAME,
> +       },
> +};
> +
> +static int __init vimc_init(void)
> +{
> +       int ret;
> +
> +       ret = platform_device_register(&vimc_pdev);
> +       if (ret) {
> +               dev_err(&vimc_pdev.dev,
> +                       "platform device registration failed (err=%d)\n", ret);
> +               return ret;
> +       }
> +
> +       ret = platform_driver_register(&vimc_pdrv);
> +       if (ret) {
> +               dev_err(&vimc_pdev.dev,
> +                       "platform driver registration failed (err=%d)\n", ret);
> +
> +               platform_device_unregister(&vimc_pdev);
> +       }
> +
> +       return ret;
> +}
> +
> +static void __exit vimc_exit(void)
> +{
> +       platform_driver_unregister(&vimc_pdrv);
> +
> +       platform_device_unregister(&vimc_pdev);
> +}
> +
> +module_init(vimc_init);
> +module_exit(vimc_exit);
> +
> +MODULE_DESCRIPTION("Virtual Media Controller Driver (VIMC)");
> +MODULE_AUTHOR("Helen Fornazier <helen.fornazier@gmail.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/media/platform/vimc/vimc-core.h b/drivers/media/platform/vimc/vimc-core.h
> new file mode 100644
> index 0000000..be05469
> --- /dev/null
> +++ b/drivers/media/platform/vimc/vimc-core.h
> @@ -0,0 +1,55 @@
> +/*
> + * vimc-core.h Virtual Media Controller Driver
> + *
> + * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef _VIMC_CORE_H_
> +#define _VIMC_CORE_H_
> +
> +#include <media/v4l2-device.h>
> +
> +/* Struct which matches the MEDIA_BUS_FMT_ codes with the corresponding
> + * V4L2_PIX_FMT_ fourcc pixelformat and its bytes per pixel (bpp) */
> +struct vimc_pix_map {
> +       unsigned int code;
> +       unsigned int bpp;
> +       u32 pixelformat;
> +};
> +extern const struct vimc_pix_map vimc_pix_map_list[];
> +
> +struct vimc_ent_device {
> +       struct media_entity *ent;
> +       struct media_pad *pads;
> +       void (*destroy)(struct vimc_ent_device *);
> +       void (*process_frame)(struct vimc_ent_device *ved,
> +                             struct media_pad *sink, const void *frame);
> +};
> +
> +int vimc_propagate_frame(struct device *dev,
> +                        struct media_pad *src, const void *frame);
> +
> +/* Helper functions to allocate/initialize pads and free them */
> +struct media_pad *vimc_pads_init(u16 num_pads,
> +                                const unsigned long *pads_flag);
> +static inline void vimc_pads_cleanup(struct media_pad *pads)
> +{
> +       kfree(pads);
> +}
> +
> +const struct vimc_pix_map *vimc_pix_map_by_code(u32 code);
> +
> +const struct vimc_pix_map *vimc_pix_map_by_pixelformat(u32 pixelformat);
> +
> +#endif
> diff --git a/drivers/media/platform/vimc/vimc-sensor.c b/drivers/media/platform/vimc/vimc-sensor.c
> new file mode 100644
> index 0000000..ae70b9e
> --- /dev/null
> +++ b/drivers/media/platform/vimc/vimc-sensor.c
> @@ -0,0 +1,277 @@
> +/*
> + * vimc-sensor.c Virtual Media Controller Driver
> + *
> + * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/freezer.h>
> +#include <linux/vmalloc.h>
> +#include <linux/v4l2-mediabus.h>
> +#include <media/v4l2-subdev.h>
> +
> +#include "vimc-sensor.h"
> +
> +struct vimc_sen_device {
> +       struct vimc_ent_device ved;
> +       struct v4l2_subdev sd;
> +       struct v4l2_device *v4l2_dev;
> +       struct device *dev;
> +       struct task_struct *kthread_sen;
> +       u8 *frame;
> +       /* The active format */
> +       struct v4l2_mbus_framefmt mbus_format;
> +       int frame_size;
> +};
> +
> +static int vimc_sen_enum_mbus_code(struct v4l2_subdev *sd,
> +                                  struct v4l2_subdev_pad_config *cfg,
> +                                  struct v4l2_subdev_mbus_code_enum *code)
> +{
> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
> +
> +       /* Check if it is a valid pad */
> +       if (code->pad >= vsen->sd.entity.num_pads)
> +               return -EINVAL;
> +
> +       code->code = vsen->mbus_format.code;
> +
> +       return 0;
> +}
> +
> +static int vimc_sen_enum_frame_size(struct v4l2_subdev *sd,
> +                                   struct v4l2_subdev_pad_config *cfg,
> +                                   struct v4l2_subdev_frame_size_enum *fse)
> +{
> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
> +
> +       /* Check if it is a valid pad */
> +       if (fse->pad >= vsen->sd.entity.num_pads ||
> +           !(vsen->sd.entity.pads[fse->pad].flags & MEDIA_PAD_FL_SOURCE))
> +               return -EINVAL;
> +
> +       /* TODO: Add support to other formats */
> +       if (fse->index)
> +               return -EINVAL;
> +
> +       /* TODO: Add support for other codes */
> +       if (fse->code != vsen->mbus_format.code)
> +               return -EINVAL;
> +
> +       fse->min_width = vsen->mbus_format.width;
> +       fse->max_width = vsen->mbus_format.width;
> +       fse->min_height = vsen->mbus_format.height;
> +       fse->max_height = vsen->mbus_format.height;
> +
> +       return 0;
> +}
> +
> +static int vimc_sen_get_fmt(struct v4l2_subdev *sd,
> +                           struct v4l2_subdev_pad_config *cfg,
> +                           struct v4l2_subdev_format *format)
> +{
> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
> +
> +       format->format = vsen->mbus_format;
> +
> +       return 0;
> +}
> +
> +static const struct v4l2_subdev_pad_ops vimc_sen_pad_ops = {
> +       .enum_mbus_code         = vimc_sen_enum_mbus_code,
> +       .enum_frame_size        = vimc_sen_enum_frame_size,
> +       .get_fmt                = vimc_sen_get_fmt,
> +       /* TODO: Add support to other formats */
> +       .set_fmt                = vimc_sen_get_fmt,
> +};
> +
> +/* media operations */
> +static const struct media_entity_operations vimc_sen_mops = {
> +       .link_validate = v4l2_subdev_link_validate,
> +};
> +
> +static int vimc_thread_sen(void *data)
> +{
> +       unsigned int i;
> +       struct vimc_sen_device *vsen = data;
> +
> +       set_freezable();
> +
> +       for (;;) {
> +               try_to_freeze();
> +               if (kthread_should_stop())
> +                       break;
> +
> +               memset(vsen->frame, 100, vsen->frame_size);
> +
> +               /* Send the frame to all source pads */
> +               for (i = 0; i < vsen->sd.entity.num_pads; i++)
> +                       if (vsen->sd.entity.pads[i].flags & MEDIA_PAD_FL_SOURCE)
> +                               vimc_propagate_frame(vsen->dev,
> +                                                    &vsen->sd.entity.pads[i],
> +                                                    vsen->frame);
> +
> +               /* Wait one second */
> +               schedule_timeout_interruptible(HZ);
> +       }
> +
> +       return 0;
> +}
> +
> +static int vimc_sen_s_stream(struct v4l2_subdev *sd, int enable)
> +{
> +       int ret;
> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
> +
> +       if (enable) {
> +               const struct vimc_pix_map *vpix;
> +
> +               if (vsen->kthread_sen)
> +                       return -EINVAL;
> +
> +               /* Calculate the frame size */
> +               vpix = vimc_pix_map_by_code(vsen->mbus_format.code);
> +               /* This should never be NULL, as we won't allow any format
> +                * other then the ones in the vimc_pix_map_list table */
> +               BUG_ON(!vpix);
> +               vsen->frame_size = vsen->mbus_format.width * vpix->bpp *
> +                                  vsen->mbus_format.height;
> +
> +               /* Allocate the frame buffer. Use vmalloc to be able to
> +                * allocate a large amount of memory*/
> +               vsen->frame = vmalloc(vsen->frame_size);
> +               if (!vsen->frame)
> +                       return -ENOMEM;
> +
> +               /* Initialize the image generator thread */
> +               vsen->kthread_sen = kthread_run(vimc_thread_sen, vsen,
> +                                               "%s-sen", vsen->v4l2_dev->name);
> +               if (IS_ERR(vsen->kthread_sen)) {
> +                       v4l2_err(vsen->v4l2_dev, "kernel_thread() failed\n");
> +                       vfree(vsen->frame);
> +                       vsen->frame = NULL;
> +                       return PTR_ERR(vsen->kthread_sen);
> +               }
> +       } else {
> +               if (!vsen->kthread_sen)
> +                       return -EINVAL;
> +
> +               /* Stop image generator */
> +               ret = kthread_stop(vsen->kthread_sen);
> +               vsen->kthread_sen = NULL;
> +
> +               vfree(vsen->frame);
> +               vsen->frame = NULL;
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +struct v4l2_subdev_video_ops vimc_sen_video_ops = {
> +       .s_stream = vimc_sen_s_stream,
> +};
> +
> +static const struct v4l2_subdev_ops vimc_sen_ops = {
> +       .pad = &vimc_sen_pad_ops,
> +       .video = &vimc_sen_video_ops,
> +};
> +
> +static void vimc_sen_destroy(struct vimc_ent_device *ved)
> +{
> +       struct vimc_sen_device *vsen = container_of(ved,
> +                                               struct vimc_sen_device, ved);
> +
> +       media_entity_cleanup(ved->ent);
> +       v4l2_device_unregister_subdev(&vsen->sd);
> +       kfree(vsen);
> +}
> +
> +struct vimc_ent_device *vimc_sen_create(struct v4l2_device *v4l2_dev,
> +                                       const char *const name,
> +                                       u16 num_pads,
> +                                       const unsigned long *pads_flag)
> +{
> +       int ret;
> +       struct vimc_sen_device *vsen;
> +
> +       if (!v4l2_dev || !v4l2_dev->dev || !name || (num_pads && !pads_flag))
> +               return ERR_PTR(-EINVAL);
> +
> +       /* Allocate the vsen struct */
> +       vsen = kzalloc(sizeof(*vsen), GFP_KERNEL);
> +       if (!vsen)
> +               return ERR_PTR(-ENOMEM);
> +
> +       /* Link the vimc_sen_device struct with the v4l2 parent */
> +       vsen->v4l2_dev = v4l2_dev;
> +       /* Link the vimc_sen_device struct with the dev parent */
> +       vsen->dev = v4l2_dev->dev;
> +
> +       /* Allocate the pads */
> +       vsen->ved.pads = vimc_pads_init(num_pads, pads_flag);
> +       if (IS_ERR(vsen->ved.pads)) {
> +               ret = PTR_ERR(vsen->ved.pads);
> +               goto err_free_vsen;
> +       }
> +
> +       /* Initialize the media entity */
> +       vsen->sd.entity.name = name;
> +       vsen->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> +       ret = media_entity_pads_init(&vsen->sd.entity,
> +                                    num_pads, vsen->ved.pads);
> +       if (ret)
> +               goto err_clean_pads;
> +
> +       /* Set the active frame format (this is hardcoded for now) */
> +       vsen->mbus_format.width = 640;
> +       vsen->mbus_format.height = 480;
> +       vsen->mbus_format.code = MEDIA_BUS_FMT_RGB888_1X24;
> +       vsen->mbus_format.field = V4L2_FIELD_NONE;
> +       vsen->mbus_format.colorspace = V4L2_COLORSPACE_SRGB;
> +       vsen->mbus_format.quantization = V4L2_QUANTIZATION_FULL_RANGE;
> +       vsen->mbus_format.xfer_func = V4L2_XFER_FUNC_SRGB;
> +
> +       /* Fill the vimc_ent_device struct */
> +       vsen->ved.destroy = vimc_sen_destroy;
> +       vsen->ved.ent = &vsen->sd.entity;
> +
> +       /* Initialize the subdev */
> +       v4l2_subdev_init(&vsen->sd, &vimc_sen_ops);
> +       vsen->sd.entity.ops = &vimc_sen_mops;
> +       vsen->sd.owner = THIS_MODULE;
> +       strlcpy(vsen->sd.name, name, sizeof(vsen->sd.name));
> +       v4l2_set_subdevdata(&vsen->sd, vsen);
> +
> +       /* Expose this subdev to user space */
> +       vsen->sd.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
> +
> +       /* Register the subdev with the v4l2 and the media framework */
> +       ret = v4l2_device_register_subdev(vsen->v4l2_dev, &vsen->sd);
> +       if (ret) {
> +               dev_err(vsen->dev,
> +                       "subdev register failed (err=%d)\n", ret);
> +               goto err_clean_m_ent;
> +       }
> +
> +       return &vsen->ved;
> +
> +err_clean_m_ent:
> +       media_entity_cleanup(&vsen->sd.entity);
> +err_clean_pads:
> +       vimc_pads_cleanup(vsen->ved.pads);
> +err_free_vsen:
> +       kfree(vsen);
> +
> +       return ERR_PTR(ret);
> +}
> diff --git a/drivers/media/platform/vimc/vimc-sensor.h b/drivers/media/platform/vimc/vimc-sensor.h
> new file mode 100644
> index 0000000..67b7e07
> --- /dev/null
> +++ b/drivers/media/platform/vimc/vimc-sensor.h
> @@ -0,0 +1,28 @@
> +/*
> + * vimc-sensor.h Virtual Media Controller Driver
> + *
> + * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef _VIMC_SENSOR_H_
> +#define _VIMC_SENSOR_H_
> +
> +#include "vimc-core.h"
> +
> +struct vimc_ent_device *vimc_sen_create(struct v4l2_device *v4l2_dev,
> +                                       const char *const name,
> +                                       u16 num_pads,
> +                                       const unsigned long *pads_flag);
> +
> +#endif
> --
> 1.9.1
>

I know everybody is busy, but is there any chance for this patch to be
reviewed or to get some comments/feedback on it?
Jeremy Gebben May 25, 2016, midnight UTC | #2
Helen,

I am more of a v4l2 newb than a reviewer, but I got your driver working 
on a qemu arm64 system. Using it to play with mediactl -p was
a good way to get started.

I did have 2 minor include path problems. Maybe they come in implicitly 
on other architectures? See below:

On 4/27/16 10:33 AM, Helen Fornazier wrote:

<SNIP>

>> diff --git a/drivers/media/platform/vimc/vimc-core.h b/drivers/media/platform/vimc/vimc-core.h
>> new file mode 100644
>> index 0000000..be05469
>> --- /dev/null
>> +++ b/drivers/media/platform/vimc/vimc-core.h
>> @@ -0,0 +1,55 @@
>> +/*
>> + * vimc-core.h Virtual Media Controller Driver
>> + *
>> + * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + */
>> +
>> +#ifndef _VIMC_CORE_H_
>> +#define _VIMC_CORE_H_
>> +
>> +#include <media/v4l2-device.h>
>> +
>> +/* Struct which matches the MEDIA_BUS_FMT_ codes with the corresponding
>> + * V4L2_PIX_FMT_ fourcc pixelformat and its bytes per pixel (bpp) */
>> +struct vimc_pix_map {
>> +       unsigned int code;
>> +       unsigned int bpp;
>> +       u32 pixelformat;
>> +};
>> +extern const struct vimc_pix_map vimc_pix_map_list[];
>> +
>> +struct vimc_ent_device {
>> +       struct media_entity *ent;
>> +       struct media_pad *pads;
>> +       void (*destroy)(struct vimc_ent_device *);
>> +       void (*process_frame)(struct vimc_ent_device *ved,
>> +                             struct media_pad *sink, const void *frame);
>> +};
>> +
>> +int vimc_propagate_frame(struct device *dev,
>> +                        struct media_pad *src, const void *frame);
>> +
>> +/* Helper functions to allocate/initialize pads and free them */
>> +struct media_pad *vimc_pads_init(u16 num_pads,
>> +                                const unsigned long *pads_flag);
>> +static inline void vimc_pads_cleanup(struct media_pad *pads)
>> +{
>> +       kfree(pads);

I needed <linux/slab.h> to be included in this file, so that kfree() was 
defined.



>> +}
>> +
>> +const struct vimc_pix_map *vimc_pix_map_by_code(u32 code);
>> +
>> +const struct vimc_pix_map *vimc_pix_map_by_pixelformat(u32 pixelformat);
>> +
>> +#endif
>> diff --git a/drivers/media/platform/vimc/vimc-sensor.c b/drivers/media/platform/vimc/vimc-sensor.c
>> new file mode 100644
>> index 0000000..ae70b9e
>> --- /dev/null
>> +++ b/drivers/media/platform/vimc/vimc-sensor.c
>> @@ -0,0 +1,277 @@
>> +/*
>> + * vimc-sensor.c Virtual Media Controller Driver
>> + *
>> + * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + */
>> +
>> +#include <linux/freezer.h>
>> +#include <linux/vmalloc.h>
>> +#include <linux/v4l2-mediabus.h>
>> +#include <media/v4l2-subdev.h>
>> +
>> +#include "vimc-sensor.h"
>> +
>> +struct vimc_sen_device {
>> +       struct vimc_ent_device ved;
>> +       struct v4l2_subdev sd;
>> +       struct v4l2_device *v4l2_dev;
>> +       struct device *dev;
>> +       struct task_struct *kthread_sen;
>> +       u8 *frame;
>> +       /* The active format */
>> +       struct v4l2_mbus_framefmt mbus_format;
>> +       int frame_size;
>> +};
>> +
>> +static int vimc_sen_enum_mbus_code(struct v4l2_subdev *sd,
>> +                                  struct v4l2_subdev_pad_config *cfg,
>> +                                  struct v4l2_subdev_mbus_code_enum *code)
>> +{
>> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
>> +
>> +       /* Check if it is a valid pad */
>> +       if (code->pad >= vsen->sd.entity.num_pads)
>> +               return -EINVAL;
>> +
>> +       code->code = vsen->mbus_format.code;
>> +
>> +       return 0;
>> +}
>> +
>> +static int vimc_sen_enum_frame_size(struct v4l2_subdev *sd,
>> +                                   struct v4l2_subdev_pad_config *cfg,
>> +                                   struct v4l2_subdev_frame_size_enum *fse)
>> +{
>> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
>> +
>> +       /* Check if it is a valid pad */
>> +       if (fse->pad >= vsen->sd.entity.num_pads ||
>> +           !(vsen->sd.entity.pads[fse->pad].flags & MEDIA_PAD_FL_SOURCE))
>> +               return -EINVAL;
>> +
>> +       /* TODO: Add support to other formats */
>> +       if (fse->index)
>> +               return -EINVAL;
>> +
>> +       /* TODO: Add support for other codes */
>> +       if (fse->code != vsen->mbus_format.code)
>> +               return -EINVAL;
>> +
>> +       fse->min_width = vsen->mbus_format.width;
>> +       fse->max_width = vsen->mbus_format.width;
>> +       fse->min_height = vsen->mbus_format.height;
>> +       fse->max_height = vsen->mbus_format.height;
>> +
>> +       return 0;
>> +}
>> +
>> +static int vimc_sen_get_fmt(struct v4l2_subdev *sd,
>> +                           struct v4l2_subdev_pad_config *cfg,
>> +                           struct v4l2_subdev_format *format)
>> +{
>> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
>> +
>> +       format->format = vsen->mbus_format;
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct v4l2_subdev_pad_ops vimc_sen_pad_ops = {
>> +       .enum_mbus_code         = vimc_sen_enum_mbus_code,
>> +       .enum_frame_size        = vimc_sen_enum_frame_size,
>> +       .get_fmt                = vimc_sen_get_fmt,
>> +       /* TODO: Add support to other formats */
>> +       .set_fmt                = vimc_sen_get_fmt,
>> +};
>> +
>> +/* media operations */
>> +static const struct media_entity_operations vimc_sen_mops = {
>> +       .link_validate = v4l2_subdev_link_validate,
>> +};
>> +
>> +static int vimc_thread_sen(void *data)
>> +{
>> +       unsigned int i;
>> +       struct vimc_sen_device *vsen = data;
>> +
>> +       set_freezable();
>> +
>> +       for (;;) {
>> +               try_to_freeze();
>> +               if (kthread_should_stop())
>> +                       break;

And I needed <linux/kthread.h> for kthread_should_stop() and other 
functions.

>> +
>> +               memset(vsen->frame, 100, vsen->frame_size);
>> +
>> +               /* Send the frame to all source pads */
>> +               for (i = 0; i < vsen->sd.entity.num_pads; i++)
>> +                       if (vsen->sd.entity.pads[i].flags & MEDIA_PAD_FL_SOURCE)
>> +                               vimc_propagate_frame(vsen->dev,
>> +                                                    &vsen->sd.entity.pads[i],
>> +                                                    vsen->frame);
>> +
>> +               /* Wait one second */
>> +               schedule_timeout_interruptible(HZ);
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int vimc_sen_s_stream(struct v4l2_subdev *sd, int enable)
>> +{
>> +       int ret;
>> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
>> +
>> +       if (enable) {
>> +               const struct vimc_pix_map *vpix;
>> +
>> +               if (vsen->kthread_sen)
>> +                       return -EINVAL;
>> +
>> +               /* Calculate the frame size */
>> +               vpix = vimc_pix_map_by_code(vsen->mbus_format.code);
>> +               /* This should never be NULL, as we won't allow any format
>> +                * other then the ones in the vimc_pix_map_list table */
>> +               BUG_ON(!vpix);
>> +               vsen->frame_size = vsen->mbus_format.width * vpix->bpp *
>> +                                  vsen->mbus_format.height;
>> +
>> +               /* Allocate the frame buffer. Use vmalloc to be able to
>> +                * allocate a large amount of memory*/
>> +               vsen->frame = vmalloc(vsen->frame_size);
>> +               if (!vsen->frame)
>> +                       return -ENOMEM;
>> +
>> +               /* Initialize the image generator thread */
>> +               vsen->kthread_sen = kthread_run(vimc_thread_sen, vsen,
>> +                                               "%s-sen", vsen->v4l2_dev->name);
>> +               if (IS_ERR(vsen->kthread_sen)) {
>> +                       v4l2_err(vsen->v4l2_dev, "kernel_thread() failed\n");
>> +                       vfree(vsen->frame);
>> +                       vsen->frame = NULL;
>> +                       return PTR_ERR(vsen->kthread_sen);
>> +               }
>> +       } else {
>> +               if (!vsen->kthread_sen)
>> +                       return -EINVAL;
>> +
>> +               /* Stop image generator */
>> +               ret = kthread_stop(vsen->kthread_sen);
>> +               vsen->kthread_sen = NULL;
>> +
>> +               vfree(vsen->frame);
>> +               vsen->frame = NULL;
>> +               return ret;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +struct v4l2_subdev_video_ops vimc_sen_video_ops = {
>> +       .s_stream = vimc_sen_s_stream,
>> +};
>> +
>> +static const struct v4l2_subdev_ops vimc_sen_ops = {
>> +       .pad = &vimc_sen_pad_ops,
>> +       .video = &vimc_sen_video_ops,
>> +};
>> +
>> +static void vimc_sen_destroy(struct vimc_ent_device *ved)
>> +{
>> +       struct vimc_sen_device *vsen = container_of(ved,
>> +                                               struct vimc_sen_device, ved);
>> +
>> +       media_entity_cleanup(ved->ent);
>> +       v4l2_device_unregister_subdev(&vsen->sd);
>> +       kfree(vsen);
>> +}
>> +
>> +struct vimc_ent_device *vimc_sen_create(struct v4l2_device *v4l2_dev,
>> +                                       const char *const name,
>> +                                       u16 num_pads,
>> +                                       const unsigned long *pads_flag)
>> +{
>> +       int ret;
>> +       struct vimc_sen_device *vsen;
>> +
>> +       if (!v4l2_dev || !v4l2_dev->dev || !name || (num_pads && !pads_flag))
>> +               return ERR_PTR(-EINVAL);
>> +
>> +       /* Allocate the vsen struct */
>> +       vsen = kzalloc(sizeof(*vsen), GFP_KERNEL);
>> +       if (!vsen)
>> +               return ERR_PTR(-ENOMEM);
>> +
>> +       /* Link the vimc_sen_device struct with the v4l2 parent */
>> +       vsen->v4l2_dev = v4l2_dev;
>> +       /* Link the vimc_sen_device struct with the dev parent */
>> +       vsen->dev = v4l2_dev->dev;
>> +
>> +       /* Allocate the pads */
>> +       vsen->ved.pads = vimc_pads_init(num_pads, pads_flag);
>> +       if (IS_ERR(vsen->ved.pads)) {
>> +               ret = PTR_ERR(vsen->ved.pads);
>> +               goto err_free_vsen;
>> +       }
>> +
>> +       /* Initialize the media entity */
>> +       vsen->sd.entity.name = name;
>> +       vsen->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
>> +       ret = media_entity_pads_init(&vsen->sd.entity,
>> +                                    num_pads, vsen->ved.pads);
>> +       if (ret)
>> +               goto err_clean_pads;
>> +
>> +       /* Set the active frame format (this is hardcoded for now) */
>> +       vsen->mbus_format.width = 640;
>> +       vsen->mbus_format.height = 480;
>> +       vsen->mbus_format.code = MEDIA_BUS_FMT_RGB888_1X24;
>> +       vsen->mbus_format.field = V4L2_FIELD_NONE;
>> +       vsen->mbus_format.colorspace = V4L2_COLORSPACE_SRGB;
>> +       vsen->mbus_format.quantization = V4L2_QUANTIZATION_FULL_RANGE;
>> +       vsen->mbus_format.xfer_func = V4L2_XFER_FUNC_SRGB;
>> +
>> +       /* Fill the vimc_ent_device struct */
>> +       vsen->ved.destroy = vimc_sen_destroy;
>> +       vsen->ved.ent = &vsen->sd.entity;
>> +
>> +       /* Initialize the subdev */
>> +       v4l2_subdev_init(&vsen->sd, &vimc_sen_ops);
>> +       vsen->sd.entity.ops = &vimc_sen_mops;
>> +       vsen->sd.owner = THIS_MODULE;
>> +       strlcpy(vsen->sd.name, name, sizeof(vsen->sd.name));
>> +       v4l2_set_subdevdata(&vsen->sd, vsen);
>> +
>> +       /* Expose this subdev to user space */
>> +       vsen->sd.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
>> +
>> +       /* Register the subdev with the v4l2 and the media framework */
>> +       ret = v4l2_device_register_subdev(vsen->v4l2_dev, &vsen->sd);
>> +       if (ret) {
>> +               dev_err(vsen->dev,
>> +                       "subdev register failed (err=%d)\n", ret);
>> +               goto err_clean_m_ent;
>> +       }
>> +
>> +       return &vsen->ved;
>> +
>> +err_clean_m_ent:
>> +       media_entity_cleanup(&vsen->sd.entity);
>> +err_clean_pads:
>> +       vimc_pads_cleanup(vsen->ved.pads);
>> +err_free_vsen:
>> +       kfree(vsen);
>> +
>> +       return ERR_PTR(ret);
>> +}

<SNIP>

>
> I know everybody is busy, but is there any chance for this patch to be
> reviewed or to get some comments/feedback on it?
>

Other than that it was easy for me to get working, at least for simple 
poking around.

Thanks,

Jeremy
Helen Koike May 25, 2016, 12:07 a.m. UTC | #3
Hi Jeremy,

On 24-05-2016 21:00, Jeremy Gebben wrote:
> Helen,
>
> I am more of a v4l2 newb than a reviewer, but I got your driver working
> on a qemu arm64 system. Using it to play with mediactl -p was
> a good way to get started.
>
> I did have 2 minor include path problems. Maybe they come in implicitly
> on other architectures? See below:
>
> On 4/27/16 10:33 AM, Helen Fornazier wrote:
>
> <SNIP>
>
>>> diff --git a/drivers/media/platform/vimc/vimc-core.h
>>> b/drivers/media/platform/vimc/vimc-core.h
>>> new file mode 100644
>>> index 0000000..be05469
>>> --- /dev/null
>>> +++ b/drivers/media/platform/vimc/vimc-core.h
>>> @@ -0,0 +1,55 @@
>>> +/*
>>> + * vimc-core.h Virtual Media Controller Driver
>>> + *
>>> + * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License as published by
>>> + * the Free Software Foundation; either version 2 of the License, or
>>> + * (at your option) any later version.
>>> + *
>>> + * This program is distributed in the hope that it will be useful,
>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>> + * GNU General Public License for more details.
>>> + *
>>> + */
>>> +
>>> +#ifndef _VIMC_CORE_H_
>>> +#define _VIMC_CORE_H_
>>> +
>>> +#include <media/v4l2-device.h>
>>> +
>>> +/* Struct which matches the MEDIA_BUS_FMT_ codes with the corresponding
>>> + * V4L2_PIX_FMT_ fourcc pixelformat and its bytes per pixel (bpp) */
>>> +struct vimc_pix_map {
>>> +       unsigned int code;
>>> +       unsigned int bpp;
>>> +       u32 pixelformat;
>>> +};
>>> +extern const struct vimc_pix_map vimc_pix_map_list[];
>>> +
>>> +struct vimc_ent_device {
>>> +       struct media_entity *ent;
>>> +       struct media_pad *pads;
>>> +       void (*destroy)(struct vimc_ent_device *);
>>> +       void (*process_frame)(struct vimc_ent_device *ved,
>>> +                             struct media_pad *sink, const void
>>> *frame);
>>> +};
>>> +
>>> +int vimc_propagate_frame(struct device *dev,
>>> +                        struct media_pad *src, const void *frame);
>>> +
>>> +/* Helper functions to allocate/initialize pads and free them */
>>> +struct media_pad *vimc_pads_init(u16 num_pads,
>>> +                                const unsigned long *pads_flag);
>>> +static inline void vimc_pads_cleanup(struct media_pad *pads)
>>> +{
>>> +       kfree(pads);
>
> I needed <linux/slab.h> to be included in this file, so that kfree() was
> defined.
>
>
>
>>> +}
>>> +
>>> +const struct vimc_pix_map *vimc_pix_map_by_code(u32 code);
>>> +
>>> +const struct vimc_pix_map *vimc_pix_map_by_pixelformat(u32
>>> pixelformat);
>>> +
>>> +#endif
>>> diff --git a/drivers/media/platform/vimc/vimc-sensor.c
>>> b/drivers/media/platform/vimc/vimc-sensor.c
>>> new file mode 100644
>>> index 0000000..ae70b9e
>>> --- /dev/null
>>> +++ b/drivers/media/platform/vimc/vimc-sensor.c
>>> @@ -0,0 +1,277 @@
>>> +/*
>>> + * vimc-sensor.c Virtual Media Controller Driver
>>> + *
>>> + * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License as published by
>>> + * the Free Software Foundation; either version 2 of the License, or
>>> + * (at your option) any later version.
>>> + *
>>> + * This program is distributed in the hope that it will be useful,
>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>> + * GNU General Public License for more details.
>>> + *
>>> + */
>>> +
>>> +#include <linux/freezer.h>
>>> +#include <linux/vmalloc.h>
>>> +#include <linux/v4l2-mediabus.h>
>>> +#include <media/v4l2-subdev.h>
>>> +
>>> +#include "vimc-sensor.h"
>>> +
>>> +struct vimc_sen_device {
>>> +       struct vimc_ent_device ved;
>>> +       struct v4l2_subdev sd;
>>> +       struct v4l2_device *v4l2_dev;
>>> +       struct device *dev;
>>> +       struct task_struct *kthread_sen;
>>> +       u8 *frame;
>>> +       /* The active format */
>>> +       struct v4l2_mbus_framefmt mbus_format;
>>> +       int frame_size;
>>> +};
>>> +
>>> +static int vimc_sen_enum_mbus_code(struct v4l2_subdev *sd,
>>> +                                  struct v4l2_subdev_pad_config *cfg,
>>> +                                  struct v4l2_subdev_mbus_code_enum
>>> *code)
>>> +{
>>> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
>>> +
>>> +       /* Check if it is a valid pad */
>>> +       if (code->pad >= vsen->sd.entity.num_pads)
>>> +               return -EINVAL;
>>> +
>>> +       code->code = vsen->mbus_format.code;
>>> +
>>> +       return 0;
>>> +}
>>> +
>>> +static int vimc_sen_enum_frame_size(struct v4l2_subdev *sd,
>>> +                                   struct v4l2_subdev_pad_config *cfg,
>>> +                                   struct
>>> v4l2_subdev_frame_size_enum *fse)
>>> +{
>>> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
>>> +
>>> +       /* Check if it is a valid pad */
>>> +       if (fse->pad >= vsen->sd.entity.num_pads ||
>>> +           !(vsen->sd.entity.pads[fse->pad].flags &
>>> MEDIA_PAD_FL_SOURCE))
>>> +               return -EINVAL;
>>> +
>>> +       /* TODO: Add support to other formats */
>>> +       if (fse->index)
>>> +               return -EINVAL;
>>> +
>>> +       /* TODO: Add support for other codes */
>>> +       if (fse->code != vsen->mbus_format.code)
>>> +               return -EINVAL;
>>> +
>>> +       fse->min_width = vsen->mbus_format.width;
>>> +       fse->max_width = vsen->mbus_format.width;
>>> +       fse->min_height = vsen->mbus_format.height;
>>> +       fse->max_height = vsen->mbus_format.height;
>>> +
>>> +       return 0;
>>> +}
>>> +
>>> +static int vimc_sen_get_fmt(struct v4l2_subdev *sd,
>>> +                           struct v4l2_subdev_pad_config *cfg,
>>> +                           struct v4l2_subdev_format *format)
>>> +{
>>> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
>>> +
>>> +       format->format = vsen->mbus_format;
>>> +
>>> +       return 0;
>>> +}
>>> +
>>> +static const struct v4l2_subdev_pad_ops vimc_sen_pad_ops = {
>>> +       .enum_mbus_code         = vimc_sen_enum_mbus_code,
>>> +       .enum_frame_size        = vimc_sen_enum_frame_size,
>>> +       .get_fmt                = vimc_sen_get_fmt,
>>> +       /* TODO: Add support to other formats */
>>> +       .set_fmt                = vimc_sen_get_fmt,
>>> +};
>>> +
>>> +/* media operations */
>>> +static const struct media_entity_operations vimc_sen_mops = {
>>> +       .link_validate = v4l2_subdev_link_validate,
>>> +};
>>> +
>>> +static int vimc_thread_sen(void *data)
>>> +{
>>> +       unsigned int i;
>>> +       struct vimc_sen_device *vsen = data;
>>> +
>>> +       set_freezable();
>>> +
>>> +       for (;;) {
>>> +               try_to_freeze();
>>> +               if (kthread_should_stop())
>>> +                       break;
>
> And I needed <linux/kthread.h> for kthread_should_stop() and other
> functions.
>
>>> +
>>> +               memset(vsen->frame, 100, vsen->frame_size);
>>> +
>>> +               /* Send the frame to all source pads */
>>> +               for (i = 0; i < vsen->sd.entity.num_pads; i++)
>>> +                       if (vsen->sd.entity.pads[i].flags &
>>> MEDIA_PAD_FL_SOURCE)
>>> +                               vimc_propagate_frame(vsen->dev,
>>> +
>>> &vsen->sd.entity.pads[i],
>>> +                                                    vsen->frame);
>>> +
>>> +               /* Wait one second */
>>> +               schedule_timeout_interruptible(HZ);
>>> +       }
>>> +
>>> +       return 0;
>>> +}
>>> +
>>> +static int vimc_sen_s_stream(struct v4l2_subdev *sd, int enable)
>>> +{
>>> +       int ret;
>>> +       struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
>>> +
>>> +       if (enable) {
>>> +               const struct vimc_pix_map *vpix;
>>> +
>>> +               if (vsen->kthread_sen)
>>> +                       return -EINVAL;
>>> +
>>> +               /* Calculate the frame size */
>>> +               vpix = vimc_pix_map_by_code(vsen->mbus_format.code);
>>> +               /* This should never be NULL, as we won't allow any
>>> format
>>> +                * other then the ones in the vimc_pix_map_list table */
>>> +               BUG_ON(!vpix);
>>> +               vsen->frame_size = vsen->mbus_format.width * vpix->bpp *
>>> +                                  vsen->mbus_format.height;
>>> +
>>> +               /* Allocate the frame buffer. Use vmalloc to be able to
>>> +                * allocate a large amount of memory*/
>>> +               vsen->frame = vmalloc(vsen->frame_size);
>>> +               if (!vsen->frame)
>>> +                       return -ENOMEM;
>>> +
>>> +               /* Initialize the image generator thread */
>>> +               vsen->kthread_sen = kthread_run(vimc_thread_sen, vsen,
>>> +                                               "%s-sen",
>>> vsen->v4l2_dev->name);
>>> +               if (IS_ERR(vsen->kthread_sen)) {
>>> +                       v4l2_err(vsen->v4l2_dev, "kernel_thread()
>>> failed\n");
>>> +                       vfree(vsen->frame);
>>> +                       vsen->frame = NULL;
>>> +                       return PTR_ERR(vsen->kthread_sen);
>>> +               }
>>> +       } else {
>>> +               if (!vsen->kthread_sen)
>>> +                       return -EINVAL;
>>> +
>>> +               /* Stop image generator */
>>> +               ret = kthread_stop(vsen->kthread_sen);
>>> +               vsen->kthread_sen = NULL;
>>> +
>>> +               vfree(vsen->frame);
>>> +               vsen->frame = NULL;
>>> +               return ret;
>>> +       }
>>> +
>>> +       return 0;
>>> +}
>>> +
>>> +struct v4l2_subdev_video_ops vimc_sen_video_ops = {
>>> +       .s_stream = vimc_sen_s_stream,
>>> +};
>>> +
>>> +static const struct v4l2_subdev_ops vimc_sen_ops = {
>>> +       .pad = &vimc_sen_pad_ops,
>>> +       .video = &vimc_sen_video_ops,
>>> +};
>>> +
>>> +static void vimc_sen_destroy(struct vimc_ent_device *ved)
>>> +{
>>> +       struct vimc_sen_device *vsen = container_of(ved,
>>> +                                               struct
>>> vimc_sen_device, ved);
>>> +
>>> +       media_entity_cleanup(ved->ent);
>>> +       v4l2_device_unregister_subdev(&vsen->sd);
>>> +       kfree(vsen);
>>> +}
>>> +
>>> +struct vimc_ent_device *vimc_sen_create(struct v4l2_device *v4l2_dev,
>>> +                                       const char *const name,
>>> +                                       u16 num_pads,
>>> +                                       const unsigned long *pads_flag)
>>> +{
>>> +       int ret;
>>> +       struct vimc_sen_device *vsen;
>>> +
>>> +       if (!v4l2_dev || !v4l2_dev->dev || !name || (num_pads &&
>>> !pads_flag))
>>> +               return ERR_PTR(-EINVAL);
>>> +
>>> +       /* Allocate the vsen struct */
>>> +       vsen = kzalloc(sizeof(*vsen), GFP_KERNEL);
>>> +       if (!vsen)
>>> +               return ERR_PTR(-ENOMEM);
>>> +
>>> +       /* Link the vimc_sen_device struct with the v4l2 parent */
>>> +       vsen->v4l2_dev = v4l2_dev;
>>> +       /* Link the vimc_sen_device struct with the dev parent */
>>> +       vsen->dev = v4l2_dev->dev;
>>> +
>>> +       /* Allocate the pads */
>>> +       vsen->ved.pads = vimc_pads_init(num_pads, pads_flag);
>>> +       if (IS_ERR(vsen->ved.pads)) {
>>> +               ret = PTR_ERR(vsen->ved.pads);
>>> +               goto err_free_vsen;
>>> +       }
>>> +
>>> +       /* Initialize the media entity */
>>> +       vsen->sd.entity.name = name;
>>> +       vsen->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
>>> +       ret = media_entity_pads_init(&vsen->sd.entity,
>>> +                                    num_pads, vsen->ved.pads);
>>> +       if (ret)
>>> +               goto err_clean_pads;
>>> +
>>> +       /* Set the active frame format (this is hardcoded for now) */
>>> +       vsen->mbus_format.width = 640;
>>> +       vsen->mbus_format.height = 480;
>>> +       vsen->mbus_format.code = MEDIA_BUS_FMT_RGB888_1X24;
>>> +       vsen->mbus_format.field = V4L2_FIELD_NONE;
>>> +       vsen->mbus_format.colorspace = V4L2_COLORSPACE_SRGB;
>>> +       vsen->mbus_format.quantization = V4L2_QUANTIZATION_FULL_RANGE;
>>> +       vsen->mbus_format.xfer_func = V4L2_XFER_FUNC_SRGB;
>>> +
>>> +       /* Fill the vimc_ent_device struct */
>>> +       vsen->ved.destroy = vimc_sen_destroy;
>>> +       vsen->ved.ent = &vsen->sd.entity;
>>> +
>>> +       /* Initialize the subdev */
>>> +       v4l2_subdev_init(&vsen->sd, &vimc_sen_ops);
>>> +       vsen->sd.entity.ops = &vimc_sen_mops;
>>> +       vsen->sd.owner = THIS_MODULE;
>>> +       strlcpy(vsen->sd.name, name, sizeof(vsen->sd.name));
>>> +       v4l2_set_subdevdata(&vsen->sd, vsen);
>>> +
>>> +       /* Expose this subdev to user space */
>>> +       vsen->sd.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
>>> +
>>> +       /* Register the subdev with the v4l2 and the media framework */
>>> +       ret = v4l2_device_register_subdev(vsen->v4l2_dev, &vsen->sd);
>>> +       if (ret) {
>>> +               dev_err(vsen->dev,
>>> +                       "subdev register failed (err=%d)\n", ret);
>>> +               goto err_clean_m_ent;
>>> +       }
>>> +
>>> +       return &vsen->ved;
>>> +
>>> +err_clean_m_ent:
>>> +       media_entity_cleanup(&vsen->sd.entity);
>>> +err_clean_pads:
>>> +       vimc_pads_cleanup(vsen->ved.pads);
>>> +err_free_vsen:
>>> +       kfree(vsen);
>>> +
>>> +       return ERR_PTR(ret);
>>> +}
>
> <SNIP>
>
>>
>> I know everybody is busy, but is there any chance for this patch to be
>> reviewed or to get some comments/feedback on it?
>>
>
> Other than that it was easy for me to get working, at least for simple
> poking around.
>
> Thanks,
>
> Jeremy
>

Thank you for checking. I'll check the things you pointed. I also have 
corrected some other minor bugs and I'll send them in the newer version.

I am also preparing a patch series that add more functionalities to it 
with the test patter generator, I still need to make some more tests in 
these series before I send it.

Thanks again,
Helen
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diff mbox

Patch

diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
index 201f5c2..14ed03f 100644
--- a/drivers/media/platform/Kconfig
+++ b/drivers/media/platform/Kconfig
@@ -284,6 +284,8 @@  menuconfig V4L_TEST_DRIVERS
 
 if V4L_TEST_DRIVERS
 
+source "drivers/media/platform/vimc/Kconfig"
+
 source "drivers/media/platform/vivid/Kconfig"
 
 config VIDEO_VIM2M
diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
index bbb7bd1..e4508fe 100644
--- a/drivers/media/platform/Makefile
+++ b/drivers/media/platform/Makefile
@@ -12,6 +12,7 @@  obj-$(CONFIG_VIDEO_OMAP3)	+= omap3isp/
 
 obj-$(CONFIG_VIDEO_VIU) += fsl-viu.o
 
+obj-$(CONFIG_VIDEO_VIMC)		+= vimc/
 obj-$(CONFIG_VIDEO_VIVID)		+= vivid/
 obj-$(CONFIG_VIDEO_VIM2M)		+= vim2m.o
 
diff --git a/drivers/media/platform/vimc/Kconfig b/drivers/media/platform/vimc/Kconfig
new file mode 100644
index 0000000..81279f4
--- /dev/null
+++ b/drivers/media/platform/vimc/Kconfig
@@ -0,0 +1,6 @@ 
+config VIDEO_VIMC
+	tristate "Virtual Media Controller Driver (VIMC)"
+	select VIDEO_V4L2_SUBDEV_API
+	default n
+	---help---
+	  Skeleton driver for Virtual Media Controller
diff --git a/drivers/media/platform/vimc/Makefile b/drivers/media/platform/vimc/Makefile
new file mode 100644
index 0000000..c45195e
--- /dev/null
+++ b/drivers/media/platform/vimc/Makefile
@@ -0,0 +1,3 @@ 
+vimc-objs := vimc-core.o vimc-capture.o vimc-sensor.o
+
+obj-$(CONFIG_VIDEO_VIMC) += vimc.o
diff --git a/drivers/media/platform/vimc/vimc-capture.c b/drivers/media/platform/vimc/vimc-capture.c
new file mode 100644
index 0000000..3fb8bfe
--- /dev/null
+++ b/drivers/media/platform/vimc/vimc-capture.c
@@ -0,0 +1,534 @@ 
+/*
+ * vimc-capture.c Virtual Media Controller Driver
+ *
+ * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <media/videobuf2-core.h>
+#include <media/videobuf2-vmalloc.h>
+#include <media/v4l2-ioctl.h>
+
+#include "vimc-capture.h"
+
+struct vimc_cap_device {
+	struct vimc_ent_device ved;
+	struct video_device vdev;
+	struct v4l2_device *v4l2_dev;
+	struct device *dev;
+	struct v4l2_pix_format format;
+	struct vb2_queue queue;
+	struct list_head buf_list;
+	/* NOTE: in a real driver, a spin lock must be used to access the
+	 * queue because the frames are generated from a hardware interruption
+	 * and the isr is not allowed to sleep.
+	 * Even if it is not necessary a spinlock in the vimc driver, we
+	 * use it here as a code reference */
+	spinlock_t qlock;
+	struct mutex lock;
+	u32 sequence;
+	struct media_pipeline pipe;
+};
+
+struct vimc_cap_buffer {
+	/*
+	 * vb2_buffer must be the first element
+	 * the videobf2 framework will allocate this struct based on
+	 * buf_struct_size and use the first sizeof(struct vb2_buffer) bytes of
+	 * memory as a vb2_buffer
+	 */
+	struct vb2_v4l2_buffer vb2;
+	struct list_head list;
+};
+
+static int vimc_cap_querycap(struct file *file, void *priv,
+			     struct v4l2_capability *cap)
+{
+	struct vimc_cap_device *vcap = video_drvdata(file);
+
+	strlcpy(cap->driver, KBUILD_MODNAME, sizeof(cap->driver));
+	strlcpy(cap->card, KBUILD_MODNAME, sizeof(cap->card));
+	snprintf(cap->bus_info, sizeof(cap->bus_info),
+		 "platform:%s", vcap->v4l2_dev->name);
+
+	cap->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
+	cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
+
+	return 0;
+}
+
+static int vimc_cap_enum_input(struct file *file, void *priv,
+			       struct v4l2_input *i)
+{
+	/* We only have one input */
+	if (i->index > 0)
+		return -EINVAL;
+
+	i->type = V4L2_INPUT_TYPE_CAMERA;
+	strlcpy(i->name, "VIMC capture", sizeof(i->name));
+
+	return 0;
+}
+
+static int vimc_cap_g_input(struct file *file, void *priv, unsigned int *i)
+{
+	/* We only have one input */
+	*i = 0;
+	return 0;
+}
+
+static int vimc_cap_s_input(struct file *file, void *priv, unsigned int i)
+{
+	/* We only have one input */
+	return i ? -EINVAL : 0;
+}
+
+static int vimc_cap_g_fmt_vid_cap(struct file *file, void *priv,
+				  struct v4l2_format *f)
+{
+	struct vimc_cap_device *vcap = video_drvdata(file);
+
+	f->fmt.pix = vcap->format;
+
+	return 0;
+}
+
+static int vimc_cap_enum_fmt_vid_cap(struct file *file, void *priv,
+				     struct v4l2_fmtdesc *f)
+{
+	struct vimc_cap_device *vcap = video_drvdata(file);
+
+	if (f->index > 0)
+		return -EINVAL;
+
+	/* We only support one format for now */
+	f->pixelformat = vcap->format.pixelformat;
+
+	return 0;
+}
+
+static const struct v4l2_file_operations vimc_cap_fops = {
+	.owner		= THIS_MODULE,
+	.open		= v4l2_fh_open,
+	.release	= vb2_fop_release,
+	.read           = vb2_fop_read,
+	.poll		= vb2_fop_poll,
+	.unlocked_ioctl = video_ioctl2,
+	.mmap           = vb2_fop_mmap,
+};
+
+static const struct v4l2_ioctl_ops vimc_cap_ioctl_ops = {
+	.vidioc_querycap = vimc_cap_querycap,
+
+	.vidioc_enum_input = vimc_cap_enum_input,
+	.vidioc_g_input = vimc_cap_g_input,
+	.vidioc_s_input = vimc_cap_s_input,
+
+	.vidioc_g_fmt_vid_cap = vimc_cap_g_fmt_vid_cap,
+	.vidioc_s_fmt_vid_cap = vimc_cap_g_fmt_vid_cap,
+	.vidioc_try_fmt_vid_cap = vimc_cap_g_fmt_vid_cap,
+	.vidioc_enum_fmt_vid_cap = vimc_cap_enum_fmt_vid_cap,
+
+	.vidioc_reqbufs = vb2_ioctl_reqbufs,
+	.vidioc_create_bufs = vb2_ioctl_create_bufs,
+	.vidioc_querybuf = vb2_ioctl_querybuf,
+	.vidioc_qbuf = vb2_ioctl_qbuf,
+	.vidioc_dqbuf = vb2_ioctl_dqbuf,
+	.vidioc_expbuf = vb2_ioctl_expbuf,
+	.vidioc_streamon = vb2_ioctl_streamon,
+	.vidioc_streamoff = vb2_ioctl_streamoff,
+};
+
+static void vimc_cap_return_all_buffers(struct vimc_cap_device *vcap,
+					enum vb2_buffer_state state)
+{
+	struct vimc_cap_buffer *vbuf, *node;
+
+	spin_lock(&vcap->qlock);
+
+	list_for_each_entry_safe(vbuf, node, &vcap->buf_list, list) {
+		vb2_buffer_done(&vbuf->vb2.vb2_buf, state);
+		list_del(&vbuf->list);
+	}
+
+	spin_unlock(&vcap->qlock);
+}
+
+static int vimc_cap_pipeline_s_stream(struct vimc_cap_device *vcap, int enable)
+{
+	int ret;
+	struct media_pad *pad;
+	struct media_entity *entity;
+	struct v4l2_subdev *sd;
+
+	/* Start the stream in the subdevice direct connected */
+	entity = &vcap->vdev.entity;
+	pad = media_entity_remote_pad(&entity->pads[0]);
+
+	/* If we are not connected to any subdev node, it means there is nothing
+	 * to activate on the pipe (e.g. we can be connected with an input
+	 * device or we are not connected at all)
+	 */
+	if (pad == NULL || !is_media_entity_v4l2_subdev(pad->entity))
+		return 0;
+
+	entity = pad->entity;
+	sd = media_entity_to_v4l2_subdev(entity);
+
+	ret = v4l2_subdev_call(sd, video, s_stream, enable);
+	if (ret && ret != -ENOIOCTLCMD)
+		return ret;
+
+	return 0;
+}
+
+static int vimc_cap_start_streaming(struct vb2_queue *vq, unsigned int count)
+{
+	struct vimc_cap_device *vcap = vb2_get_drv_priv(vq);
+	struct media_entity *entity;
+	int ret;
+
+	vcap->sequence = 0;
+
+	/* Start the media pipeline */
+	entity = &vcap->vdev.entity;
+	ret = media_entity_pipeline_start(entity, &vcap->pipe);
+	if (ret) {
+		vimc_cap_return_all_buffers(vcap, VB2_BUF_STATE_QUEUED);
+		return ret;
+	}
+
+	/* Enable streaming from the pipe */
+	ret = vimc_cap_pipeline_s_stream(vcap, 1);
+	if (ret) {
+		vimc_cap_return_all_buffers(vcap, VB2_BUF_STATE_QUEUED);
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Stop the stream engine. Any remaining buffers in the stream queue are
+ * dequeued and passed on to the vb2 framework marked as STATE_ERROR.
+ */
+static void vimc_cap_stop_streaming(struct vb2_queue *vq)
+{
+	struct vimc_cap_device *vcap = vb2_get_drv_priv(vq);
+
+	/* Disable streaming from the pipe */
+	vimc_cap_pipeline_s_stream(vcap, 0);
+
+	/* Stop the media pipeline */
+	media_entity_pipeline_stop(&vcap->vdev.entity);
+
+	/* Release all active buffers */
+	vimc_cap_return_all_buffers(vcap, VB2_BUF_STATE_ERROR);
+}
+
+static void vimc_cap_buf_queue(struct vb2_buffer *vb2_buf)
+{
+	struct vimc_cap_device *vcap = vb2_get_drv_priv(vb2_buf->vb2_queue);
+	struct vimc_cap_buffer *buf = container_of(vb2_buf,
+					struct vimc_cap_buffer, vb2.vb2_buf);
+
+	/* If the buffer doesn't have enough size, mark it as error */
+	if (vb2_buf->planes[0].length < vcap->format.sizeimage) {
+		vb2_buffer_done(vb2_buf, VB2_BUF_STATE_ERROR);
+		return;
+	}
+
+	spin_lock(&vcap->qlock);
+
+	list_add_tail(&buf->list, &vcap->buf_list);
+
+	spin_unlock(&vcap->qlock);
+}
+
+static int vimc_cap_queue_setup(struct vb2_queue *vq,
+				unsigned int *nbuffers, unsigned int *nplanes,
+				unsigned int sizes[], void *alloc_ctxs[])
+{
+	struct vimc_cap_device *vcap = vb2_get_drv_priv(vq);
+
+	/* We don't support multiplanes for now */
+	*nplanes = 1;
+	sizes[0] = vcap->format.sizeimage;
+
+	return 0;
+}
+
+static const struct vb2_ops vimc_cap_qops = {
+	.start_streaming	= vimc_cap_start_streaming,
+	.stop_streaming		= vimc_cap_stop_streaming,
+	.buf_queue		= vimc_cap_buf_queue,
+	.queue_setup		= vimc_cap_queue_setup,
+	/*
+	 * Since q->lock is set we can use the standard
+	 * vb2_ops_wait_prepare/finish helper functions.
+	 */
+	.wait_prepare		= vb2_ops_wait_prepare,
+	.wait_finish		= vb2_ops_wait_finish,
+};
+
+/* NOTE: this function is a copy of v4l2_subdev_link_validate_get_format
+ * maybe the v4l2 function should be public */
+static int vimc_cap_v4l2_subdev_link_validate_get_format(struct media_pad *pad,
+						struct v4l2_subdev_format *fmt)
+{
+	struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(pad->entity);
+
+	fmt->which = V4L2_SUBDEV_FORMAT_ACTIVE;
+	fmt->pad = pad->index;
+	return v4l2_subdev_call(sd, pad, get_fmt, NULL, fmt);
+}
+
+static int vimc_cap_link_validate(struct media_link *link)
+{
+	struct v4l2_subdev_format source_fmt;
+	struct v4l2_pix_format *sink_fmt;
+	struct vimc_cap_device *vcap;
+	const struct vimc_pix_map *vpix;
+	int ret;
+
+	/* Retrieve the video capture device */
+	vcap = container_of(link->sink->entity,
+			    struct vimc_cap_device, vdev.entity);
+
+	/* If the connected node is not a subdevice type
+	 * then it's a raw node from vimc-core, ignore the link for now
+	 * TODO: remove this when there are no more raw nodes in the
+	 * core and return error instead */
+	if (!is_media_entity_v4l2_subdev(link->source->entity))
+		return 0;
+
+	/* Get the the format of the video device */
+	sink_fmt = &vcap->format;
+
+	/* Get the the format of the subdev */
+	ret = vimc_cap_v4l2_subdev_link_validate_get_format(link->source,
+							    &source_fmt);
+	if (ret)
+		return ret;
+
+	dev_dbg(vcap->dev,
+		"cap: %s: link validate formats src:%dx%d %d sink:%dx%d %d\n",
+		vcap->vdev.name,
+		source_fmt.format.width, source_fmt.format.height,
+		source_fmt.format.code,
+		sink_fmt->width, sink_fmt->height,
+		sink_fmt->pixelformat);
+
+	/* Validate the format */
+
+	vpix = vimc_pix_map_by_pixelformat(sink_fmt->pixelformat);
+	if (!vpix)
+		return -EINVAL;
+
+	/* The width, height and code must match. */
+	if (source_fmt.format.width != sink_fmt->width
+	    || source_fmt.format.height != sink_fmt->height
+	    || vpix->code != source_fmt.format.code)
+		return -EINVAL;
+
+	/* The field order must match, or the sink field order must be NONE
+	 * to support interlaced hardware connected to bridges that support
+	 * progressive formats only.
+	 */
+	if (source_fmt.format.field != sink_fmt->field &&
+	    sink_fmt->field != V4L2_FIELD_NONE)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct media_entity_operations vimc_cap_mops = {
+	.link_validate		= vimc_cap_link_validate,
+};
+
+static void vimc_cap_destroy(struct vimc_ent_device *ved)
+{
+	struct vimc_cap_device *vcap = container_of(ved, struct vimc_cap_device,
+						    ved);
+
+	vb2_queue_release(&vcap->queue);
+	media_entity_cleanup(ved->ent);
+	video_unregister_device(&vcap->vdev);
+	vimc_pads_cleanup(vcap->ved.pads);
+	kfree(vcap);
+}
+
+static void vimc_cap_process_frame(struct vimc_ent_device *ved,
+				   struct media_pad *sink, const void *frame)
+{
+	struct vimc_cap_device *vcap = container_of(ved, struct vimc_cap_device,
+						    ved);
+	struct vimc_cap_buffer *vimc_buf;
+	void *vbuf;
+
+	/* If the stream in this node is not active, just return */
+	mutex_lock(&vcap->lock);
+	if (!vb2_is_busy(&vcap->queue)) {
+		mutex_unlock(&vcap->lock);
+		return;
+	}
+	mutex_unlock(&vcap->lock);
+
+	spin_lock(&vcap->qlock);
+
+	/* Get the first entry of the list */
+	vimc_buf = list_first_entry_or_null(&vcap->buf_list,
+					    typeof(*vimc_buf), list);
+	if (!vimc_buf) {
+		spin_unlock(&vcap->qlock);
+		return;
+	}
+
+	/* Remove this entry from the list */
+	list_del(&vimc_buf->list);
+
+	spin_unlock(&vcap->qlock);
+
+	/* Fill the buffer */
+	vimc_buf->vb2.vb2_buf.timestamp = ktime_get_ns();
+	vimc_buf->vb2.sequence = vcap->sequence++;
+	vimc_buf->vb2.field = vcap->format.field;
+
+	vbuf = vb2_plane_vaddr(&vimc_buf->vb2.vb2_buf, 0);
+
+	memcpy(vbuf, frame, vcap->format.sizeimage);
+
+	/* Set it as ready */
+	vb2_set_plane_payload(&vimc_buf->vb2.vb2_buf, 0,
+			      vcap->format.sizeimage);
+	vb2_buffer_done(&vimc_buf->vb2.vb2_buf, VB2_BUF_STATE_DONE);
+}
+
+struct vimc_ent_device *vimc_cap_create(struct v4l2_device *v4l2_dev,
+					const char *const name,
+					u16 num_pads,
+					const unsigned long *pads_flag)
+{
+	int ret;
+	struct vb2_queue *q;
+	struct video_device *vdev;
+	struct vimc_cap_device *vcap;
+	const struct vimc_pix_map *vpix;
+
+	if (!v4l2_dev || !v4l2_dev->dev || !name || (num_pads && !pads_flag))
+		return ERR_PTR(-EINVAL);
+
+	/* Allocate the vimc_cap_device struct */
+	vcap = kzalloc(sizeof(*vcap), GFP_KERNEL);
+	if (!vcap)
+		return ERR_PTR(-ENOMEM);
+
+	/* Link the vimc_cap_device struct with v4l2 and dev parent */
+	vcap->v4l2_dev = v4l2_dev;
+	vcap->dev = v4l2_dev->dev;
+
+	/* Allocate the pads */
+	vcap->ved.pads = vimc_pads_init(num_pads, pads_flag);
+	if (IS_ERR(vcap->ved.pads)) {
+		ret = PTR_ERR(vcap->ved.pads);
+		goto err_free_vcap;
+	}
+
+	/* Initialize the media entity */
+	vcap->vdev.entity.name = name;
+	vcap->vdev.entity.function = MEDIA_ENT_F_IO_V4L;
+	ret = media_entity_pads_init(&vcap->vdev.entity,
+				     num_pads, vcap->ved.pads);
+	if (ret)
+		goto err_clean_pads;
+
+	/* Initialize the lock */
+	mutex_init(&vcap->lock);
+
+	/* Initialize the vb2 queue */
+	q = &vcap->queue;
+	q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	q->io_modes = VB2_MMAP | VB2_DMABUF;
+	q->drv_priv = vcap;
+	q->buf_struct_size = sizeof(struct vimc_cap_buffer);
+	q->ops = &vimc_cap_qops;
+	q->mem_ops = &vb2_vmalloc_memops;
+	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	q->min_buffers_needed = 2;
+	q->lock = &vcap->lock;
+
+	ret = vb2_queue_init(q);
+	if (ret) {
+		dev_err(vcap->dev,
+			"vb2 queue init failed (err=%d)\n", ret);
+		goto err_clean_m_ent;
+	}
+
+	/* Initialize buffer list and its lock */
+	INIT_LIST_HEAD(&vcap->buf_list);
+	spin_lock_init(&vcap->qlock);
+
+	/* Set the frame format (this is hardcoded for now) */
+	vcap->format.width = 640;
+	vcap->format.height = 480;
+	vcap->format.pixelformat = V4L2_PIX_FMT_RGB24;
+	vcap->format.field = V4L2_FIELD_NONE;
+	vcap->format.colorspace = V4L2_COLORSPACE_SRGB;
+
+	vpix = vimc_pix_map_by_pixelformat(vcap->format.pixelformat);
+	/* This should never be NULL, as we won't allow any format
+	 * other then the ones in the vimc_pix_map_list table */
+	BUG_ON(!vpix);
+
+	vcap->format.bytesperline = vcap->format.width * vpix->bpp;
+	vcap->format.sizeimage = vcap->format.bytesperline * vcap->format.height;
+
+	/* Fill the vimc_ent_device struct */
+	vcap->ved.destroy = vimc_cap_destroy;
+	vcap->ved.ent = &vcap->vdev.entity;
+	vcap->ved.process_frame = vimc_cap_process_frame;
+
+	/* Initialize the video_device struct */
+	vdev = &vcap->vdev;
+	vdev->entity.ops = &vimc_cap_mops;
+	vdev->release = video_device_release_empty;
+	vdev->fops = &vimc_cap_fops;
+	vdev->ioctl_ops = &vimc_cap_ioctl_ops;
+	vdev->lock = &vcap->lock;
+	vdev->queue = q;
+	vdev->v4l2_dev = vcap->v4l2_dev;
+	vdev->vfl_dir = VFL_DIR_RX;
+	strlcpy(vdev->name, name, sizeof(vdev->name));
+	video_set_drvdata(vdev, vcap);
+
+	/* Register the video_device with the v4l2 and the media framework */
+	ret = video_register_device(vdev, VFL_TYPE_GRABBER, -1);
+	if (ret) {
+		dev_err(vcap->dev,
+			"video register failed (err=%d)\n", ret);
+		goto err_release_queue;
+	}
+
+	return &vcap->ved;
+
+err_release_queue:
+	vb2_queue_release(q);
+err_clean_m_ent:
+	media_entity_cleanup(&vcap->vdev.entity);
+err_clean_pads:
+	vimc_pads_cleanup(vcap->ved.pads);
+err_free_vcap:
+	kfree(vcap);
+
+	return ERR_PTR(ret);
+}
diff --git a/drivers/media/platform/vimc/vimc-capture.h b/drivers/media/platform/vimc/vimc-capture.h
new file mode 100644
index 0000000..c52781a
--- /dev/null
+++ b/drivers/media/platform/vimc/vimc-capture.h
@@ -0,0 +1,28 @@ 
+/*
+ * vimc-capture.h Virtual Media Controller Driver
+ *
+ * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _VIMC_CAPTURE_H_
+#define _VIMC_CAPTURE_H_
+
+#include "vimc-core.h"
+
+struct vimc_ent_device *vimc_cap_create(struct v4l2_device *v4l2_dev,
+					const char *const name,
+					u16 num_pads,
+					const unsigned long *pads_flag);
+
+#endif
diff --git a/drivers/media/platform/vimc/vimc-core.c b/drivers/media/platform/vimc/vimc-core.c
new file mode 100644
index 0000000..04c5297
--- /dev/null
+++ b/drivers/media/platform/vimc/vimc-core.c
@@ -0,0 +1,595 @@ 
+/*
+ * vimc-core.c Virtual Media Controller Driver
+ *
+ * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <media/media-device.h>
+#include <media/v4l2-device.h>
+
+#include "vimc-capture.h"
+#include "vimc-core.h"
+#include "vimc-sensor.h"
+
+#define VIMC_PDEV_NAME "vimc"
+#define VIMC_MDEV_MODEL_NAME "VIMC MDEV"
+
+#define VIMC_ENT_LINK(src, srcpad, sink, sinkpad, link_flags) {	\
+	.src_ent = src,						\
+	.src_pad = srcpad,					\
+	.sink_ent = sink,					\
+	.sink_pad = sinkpad,					\
+	.flags = link_flags,					\
+}
+
+#define VIMC_PIX_MAP(_code, _bpp, _pixelformat) {	\
+	.code = _code,					\
+	.pixelformat = _pixelformat,			\
+	.bpp = _bpp,					\
+}
+
+struct vimc_device {
+	/* The pipeline configuration
+	 * (filled before calling vimc_device_register) */
+	const struct vimc_pipeline_config *pipe_cfg;
+
+	/* The Associated media_device parent */
+	struct media_device mdev;
+
+	/* Internal v4l2 parent device*/
+	struct v4l2_device v4l2_dev;
+
+	/* Internal topology */
+	struct vimc_ent_device **ved;
+};
+
+/**
+ * enum vimc_ent_node - Select the functionality of a node in the topology
+ * @VIMC_ENT_NODE_SENSOR:	A node of type SENSOR simulates a camera sensor
+ *				generating internal images in bayer format and
+ *				propagating those images through the pipeline
+ * @VIMC_ENT_NODE_CAPTURE:	A node of type CAPTURE is a v4l2 video_device
+ *				that exposes the received image from the
+ *				pipeline to the user space
+ * @VIMC_ENT_NODE_INPUT:	A node of type INPUT is a v4l2 video_device that
+ *				receives images from the user space and
+ *				propagates them through the pipeline
+ * @VIMC_ENT_NODE_DEBAYER:	A node type DEBAYER expects to receive a frame
+ *				in bayer format converts it to RGB
+ * @VIMC_ENT_NODE_SCALER:	A node of type SCALER scales the received image
+ *				by a given multiplier
+ *
+ * This enum is used in the entity configuration struct to allow the definition
+ * of a custom topology specifying the role of each node on it.
+ */
+enum vimc_ent_node {
+	VIMC_ENT_NODE_SENSOR,
+	VIMC_ENT_NODE_CAPTURE,
+	VIMC_ENT_NODE_INPUT,
+	VIMC_ENT_NODE_DEBAYER,
+	VIMC_ENT_NODE_SCALER,
+};
+
+/* Structure which describes individual configuration for each entity */
+struct vimc_ent_config {
+	const char *name;
+	size_t pads_qty;
+	const unsigned long *pads_flag;
+	enum vimc_ent_node node;
+};
+
+/* Structure which describes links between entities */
+struct vimc_ent_link {
+	unsigned int src_ent;
+	u16 src_pad;
+	unsigned int sink_ent;
+	u16 sink_pad;
+	u32 flags;
+};
+
+/* Structure which describes the whole topology */
+struct vimc_pipeline_config {
+	const struct vimc_ent_config *ents;
+	size_t num_ents;
+	const struct vimc_ent_link *links;
+	size_t num_links;
+};
+
+/* --------------------------------------------------------------------------
+ * Topology Configuration
+ */
+
+static const struct vimc_ent_config ent_config[] = {
+	{
+		.name = "Sensor A",
+		.pads_qty = 1,
+		.pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SOURCE},
+		.node = VIMC_ENT_NODE_SENSOR,
+	},
+	{
+		.name = "Sensor B",
+		.pads_qty = 1,
+		.pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SOURCE},
+		.node = VIMC_ENT_NODE_SENSOR,
+	},
+	{
+		.name = "Debayer A",
+		.pads_qty = 2,
+		.pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK,
+						     MEDIA_PAD_FL_SOURCE},
+		.node = VIMC_ENT_NODE_DEBAYER,
+	},
+	{
+		.name = "Debayer B",
+		.pads_qty = 2,
+		.pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK,
+						     MEDIA_PAD_FL_SOURCE},
+		.node = VIMC_ENT_NODE_DEBAYER,
+	},
+	{
+		.name = "Raw Capture 0",
+		.pads_qty = 1,
+		.pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK},
+		.node = VIMC_ENT_NODE_CAPTURE,
+	},
+	{
+		.name = "Raw Capture 1",
+		.pads_qty = 1,
+		.pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK},
+		.node = VIMC_ENT_NODE_CAPTURE,
+	},
+	{
+		.name = "RGB/YUV Input",
+		.pads_qty = 1,
+		.pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SOURCE},
+		.node = VIMC_ENT_NODE_INPUT,
+	},
+	{
+		.name = "Scaler",
+		.pads_qty = 2,
+		.pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK,
+						     MEDIA_PAD_FL_SOURCE},
+		.node = VIMC_ENT_NODE_SCALER,
+	},
+	{
+		.name = "RGB/YUV Capture",
+		.pads_qty = 1,
+		.pads_flag = (const unsigned long[]){MEDIA_PAD_FL_SINK},
+		.node = VIMC_ENT_NODE_CAPTURE,
+	},
+};
+
+static const struct vimc_ent_link ent_links[] = {
+	/* Link: Sensor A (Pad 0)->(Pad 0) Debayer A */
+	VIMC_ENT_LINK(0, 0, 2, 0, MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
+	/* Link: Sensor A (Pad 0)->(Pad 0) Raw Capture 0 */
+	VIMC_ENT_LINK(0, 0, 4, 0, MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
+	/* Link: Sensor B (Pad 0)->(Pad 0) Debayer B */
+	VIMC_ENT_LINK(1, 0, 3, 0, MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
+	/* Link: Sensor B (Pad 0)->(Pad 0) Raw Capture 1 */
+	VIMC_ENT_LINK(1, 0, 5, 0, MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
+	/* Link: Debayer A (Pad 1)->(Pad 0) Scaler */
+	VIMC_ENT_LINK(2, 1, 7, 0, MEDIA_LNK_FL_ENABLED),
+	/* Link: Debayer B (Pad 1)->(Pad 0) Scaler */
+	VIMC_ENT_LINK(3, 1, 7, 0, 0),
+	/* Link: RGB/YUV Input (Pad 0)->(Pad 0) Scaler */
+	VIMC_ENT_LINK(6, 0, 7, 0, 0),
+	/* Link: Scaler (Pad 1)->(Pad 0) RGB/YUV Capture */
+	VIMC_ENT_LINK(7, 1, 8, 0, MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE),
+};
+
+static const struct vimc_pipeline_config pipe_cfg = {
+	.ents		= ent_config,
+	.num_ents	= ARRAY_SIZE(ent_config),
+	.links		= ent_links,
+	.num_links	= ARRAY_SIZE(ent_links)
+};
+
+/* -------------------------------------------------------------------------- */
+
+static void vimc_dev_release(struct device *dev)
+{}
+
+static struct platform_device vimc_pdev = {
+	.name		= VIMC_PDEV_NAME,
+	.dev.release	= vimc_dev_release,
+};
+
+const struct vimc_pix_map vimc_pix_map_list[] = {
+	/* TODO: add all missing formats */
+
+	/* RGB formats */
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_BGR888_1X24, 3, V4L2_PIX_FMT_BGR24),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_RGB888_1X24, 3, V4L2_PIX_FMT_RGB24),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_ARGB8888_1X32, 4, V4L2_PIX_FMT_ARGB32),
+
+	/* Bayer formats */
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SBGGR8_1X8, 1, V4L2_PIX_FMT_SBGGR8),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SGBRG8_1X8, 1, V4L2_PIX_FMT_SGBRG8),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SGRBG8_1X8, 1, V4L2_PIX_FMT_SGRBG8),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SRGGB8_1X8, 1, V4L2_PIX_FMT_SRGGB8),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SBGGR10_1X10, 2, V4L2_PIX_FMT_SBGGR10),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SGBRG10_1X10, 2, V4L2_PIX_FMT_SGBRG10),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SGRBG10_1X10, 2, V4L2_PIX_FMT_SGRBG10),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SRGGB10_1X10, 2, V4L2_PIX_FMT_SRGGB10),
+	/* 10bit raw bayer a-law compressed to 8 bits */
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SBGGR10_ALAW8_1X8, 1, V4L2_PIX_FMT_SBGGR10ALAW8),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SGBRG10_ALAW8_1X8, 1, V4L2_PIX_FMT_SGBRG10ALAW8),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SGRBG10_ALAW8_1X8, 1, V4L2_PIX_FMT_SGRBG10ALAW8),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SRGGB10_ALAW8_1X8, 1, V4L2_PIX_FMT_SRGGB10ALAW8),
+	/* 10bit raw bayer DPCM compressed to 8 bits */
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SBGGR10_DPCM8_1X8, 1, V4L2_PIX_FMT_SBGGR10DPCM8),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SGBRG10_DPCM8_1X8, 1, V4L2_PIX_FMT_SGBRG10DPCM8),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SGRBG10_DPCM8_1X8, 1, V4L2_PIX_FMT_SGRBG10DPCM8),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SRGGB10_DPCM8_1X8, 1, V4L2_PIX_FMT_SRGGB10DPCM8),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SBGGR12_1X12, 2, V4L2_PIX_FMT_SBGGR12),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SGBRG12_1X12, 2, V4L2_PIX_FMT_SGBRG12),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SGRBG12_1X12, 2, V4L2_PIX_FMT_SGRBG12),
+	VIMC_PIX_MAP(MEDIA_BUS_FMT_SRGGB12_1X12, 2, V4L2_PIX_FMT_SRGGB12),
+
+	/* End */
+	{0, 0, 0}
+};
+
+const struct vimc_pix_map *vimc_pix_map_by_code(u32 code)
+{
+	unsigned int i;
+
+	for (i = 0; vimc_pix_map_list[i].bpp; i++) {
+		if (vimc_pix_map_list[i].code == code)
+			return &vimc_pix_map_list[i];
+	}
+	return NULL;
+}
+
+const struct vimc_pix_map *vimc_pix_map_by_pixelformat(u32 pixelformat)
+{
+	unsigned int i;
+
+	for (i = 0; vimc_pix_map_list[i].bpp; i++) {
+		if (vimc_pix_map_list[i].pixelformat == pixelformat)
+			return &vimc_pix_map_list[i];
+	}
+	return NULL;
+}
+
+int vimc_propagate_frame(struct device *dev,
+			 struct media_pad *src, const void *frame)
+{
+	struct media_link *link;
+	struct vimc_device *vimc = dev_get_drvdata(dev);
+
+	if (!(src->flags & MEDIA_PAD_FL_SOURCE))
+		return -EINVAL;
+
+	/* Send this frame to all sink pads that are direct linked */
+	list_for_each_entry(link, &src->entity->links, list) {
+		if (link->source == src &&
+		    (link->flags & MEDIA_LNK_FL_ENABLED)) {
+			struct vimc_ent_device *ved;
+
+			ved = vimc->ved[link->sink->entity->use_count];
+			if (ved && ved->process_frame)
+				ved->process_frame(ved, link->sink, frame);
+		}
+	}
+
+	return 0;
+}
+
+static void vimc_device_unregister(struct vimc_device *vimc)
+{
+	unsigned int i;
+
+	v4l2_device_unregister(&vimc->v4l2_dev);
+
+	media_device_unregister(&vimc->mdev);
+	media_device_cleanup(&vimc->mdev);
+
+	/* Cleanup (only initialized) entities */
+	for (i = 0; i < vimc->pipe_cfg->num_ents; i++) {
+		if (vimc->ved[i] && vimc->ved[i]->destroy)
+			vimc->ved[i]->destroy(vimc->ved[i]);
+
+		vimc->ved[i] = NULL;
+	}
+}
+
+/* Helper function to allocate and initialize pads */
+struct media_pad *vimc_pads_init(u16 num_pads, const unsigned long *pads_flag)
+{
+	unsigned int i;
+	struct media_pad *pads;
+
+	/* Allocate memory for the pads */
+	pads = kcalloc(num_pads, sizeof(*pads), GFP_KERNEL);
+	if (!pads)
+		return ERR_PTR(-ENOMEM);
+
+	/* Initialize the pads */
+	for (i = 0; i < num_pads; i++) {
+		pads[i].index = i;
+		pads[i].flags = pads_flag[i];
+	}
+
+	return pads;
+}
+
+/* TODO: remove this function when all the
+ * entities specific code are implemented */
+static void vimc_raw_destroy(struct vimc_ent_device *ved)
+{
+	media_entity_cleanup(ved->ent);
+
+	vimc_pads_cleanup(ved->pads);
+
+	kfree(ved->ent);
+
+	kfree(ved);
+}
+
+/* TODO: remove this function when all the
+ * entities specific code are implemented */
+static struct vimc_ent_device *vimc_raw_create(struct v4l2_device *v4l2_dev,
+					       const char *const name,
+					       u16 num_pads,
+					       const unsigned long *pads_flag)
+{
+	int ret;
+	struct vimc_ent_device *ved;
+
+	/* Allocate the main ved struct */
+	ved = kzalloc(sizeof(*ved), GFP_KERNEL);
+	if (!ved)
+		return ERR_PTR(-ENOMEM);
+
+	/* Allocate the media entity */
+	ved->ent = kzalloc(sizeof(*ved->ent), GFP_KERNEL);
+	if (!ved->ent) {
+		ret = -ENOMEM;
+		goto err_free_ved;
+	}
+
+	/* Allocate the pads */
+	ved->pads = vimc_pads_init(num_pads, pads_flag);
+	if (IS_ERR(ved->pads)) {
+		ret = PTR_ERR(ved->pads);
+		goto err_free_ent;
+	}
+
+	/* Initialize the media entity */
+	ved->ent->name = name;
+	ved->ent->function = MEDIA_ENT_F_IO_V4L;
+	ret = media_entity_pads_init(ved->ent, num_pads, ved->pads);
+	if (ret)
+		goto err_cleanup_pads;
+
+	/* Register the media entity */
+	ret = media_device_register_entity(v4l2_dev->mdev, ved->ent);
+	if (ret)
+		goto err_cleanup_entity;
+
+	/* Fill out the destroy function and return */
+	ved->destroy = vimc_raw_destroy;
+	return ved;
+
+err_cleanup_entity:
+	media_entity_cleanup(ved->ent);
+err_cleanup_pads:
+	vimc_pads_cleanup(ved->pads);
+err_free_ent:
+	kfree(ved->ent);
+err_free_ved:
+	kfree(ved);
+
+	return ERR_PTR(ret);
+}
+
+static int vimc_device_register(struct vimc_device *vimc)
+{
+	unsigned int i;
+	int ret = 0;
+
+	/* Allocate memory for the vimc_ent_devices pointers */
+	vimc->ved = devm_kcalloc(vimc->mdev.dev, vimc->pipe_cfg->num_ents,
+				 sizeof(*vimc->ved), GFP_KERNEL);
+	if (!vimc->ved)
+		return -ENOMEM;
+
+	/* Register the media device */
+	ret = media_device_register(&vimc->mdev);
+	if (ret) {
+		dev_err(vimc->mdev.dev,
+			"media device register failed (err=%d)\n", ret);
+		return ret;
+	}
+
+	/* Link the media device within the v4l2_device */
+	vimc->v4l2_dev.mdev = &vimc->mdev;
+
+	/* Register the v4l2 struct */
+	ret = v4l2_device_register(vimc->mdev.dev, &vimc->v4l2_dev);
+	if (ret) {
+		dev_err(vimc->mdev.dev,
+			"v4l2 device register failed (err=%d)\n", ret);
+		return ret;
+	}
+
+	/* Initialize entities */
+	for (i = 0; i < vimc->pipe_cfg->num_ents; i++) {
+		struct vimc_ent_device *(*create_func)(struct v4l2_device *,
+						       const char *const,
+						       u16,
+						       const unsigned long *);
+
+		/* Register the specific node */
+		switch (vimc->pipe_cfg->ents[i].node) {
+		case VIMC_ENT_NODE_SENSOR:
+			create_func = vimc_sen_create;
+			break;
+
+		case VIMC_ENT_NODE_CAPTURE:
+			create_func = vimc_cap_create;
+			break;
+
+		/* TODO: Instantiate the specific topology node */
+		case VIMC_ENT_NODE_INPUT:
+		case VIMC_ENT_NODE_DEBAYER:
+		case VIMC_ENT_NODE_SCALER:
+		default:
+			/* TODO: remove this when all the entities specific
+			 * code are implemented */
+			create_func = vimc_raw_create;
+			break;
+		}
+
+		vimc->ved[i] = create_func(&vimc->v4l2_dev,
+					   vimc->pipe_cfg->ents[i].name,
+					   vimc->pipe_cfg->ents[i].pads_qty,
+					   vimc->pipe_cfg->ents[i].pads_flag);
+		if (IS_ERR(vimc->ved[i])) {
+			ret = PTR_ERR(vimc->ved[i]);
+			vimc->ved[i] = NULL;
+			goto err;
+		}
+
+		/* Set use_count to keep track of the ved structure */
+		vimc->ved[i]->ent->use_count = i;
+	}
+
+	/* Initialize the links between entities */
+	for (i = 0; i < vimc->pipe_cfg->num_links; i++) {
+		const struct vimc_ent_link *link = &vimc->pipe_cfg->links[i];
+
+		ret = media_create_pad_link(vimc->ved[link->src_ent]->ent,
+					    link->src_pad,
+					    vimc->ved[link->sink_ent]->ent,
+					    link->sink_pad,
+					    link->flags);
+		if (ret)
+			goto err;
+	}
+
+	/* Expose all subdev's nodes*/
+	ret = v4l2_device_register_subdev_nodes(&vimc->v4l2_dev);
+	if (ret) {
+		dev_err(vimc->mdev.dev,
+			"vimc subdev nodes registration failed (err=%d)\n", ret);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	/* Destroy de so far created topology */
+	vimc_device_unregister(vimc);
+
+	return ret;
+}
+
+static int vimc_probe(struct platform_device *pdev)
+{
+	struct vimc_device *vimc;
+	int ret;
+
+	/* Prepare the vimc topology structure */
+
+	/* Allocate memory for the vimc structure */
+	vimc = devm_kzalloc(&pdev->dev, sizeof(*vimc), GFP_KERNEL);
+	if (!vimc)
+		return -ENOMEM;
+
+	/* Set the pipeline configuration struct */
+	vimc->pipe_cfg = &pipe_cfg;
+
+	/* Initialize media device */
+	strlcpy(vimc->mdev.model, VIMC_MDEV_MODEL_NAME,
+		sizeof(vimc->mdev.model));
+	vimc->mdev.dev = &pdev->dev;
+	media_device_init(&vimc->mdev);
+
+	/* Create vimc topology */
+	ret = vimc_device_register(vimc);
+	if (ret) {
+		dev_err(vimc->mdev.dev,
+			"vimc device registration failed (err=%d)\n", ret);
+		return ret;
+	}
+
+	/* Link the topology object with the platform device object */
+	platform_set_drvdata(pdev, vimc);
+
+	return 0;
+}
+
+static int vimc_remove(struct platform_device *pdev)
+{
+	struct vimc_device *vimc;
+
+	/* Get the topology object linked with the platform device object */
+	vimc = platform_get_drvdata(pdev);
+
+	/* Destroy all the topology */
+	vimc_device_unregister(vimc);
+
+	return 0;
+}
+
+static struct platform_driver vimc_pdrv = {
+	.probe		= vimc_probe,
+	.remove		= vimc_remove,
+	.driver		= {
+		.name	= VIMC_PDEV_NAME,
+	},
+};
+
+static int __init vimc_init(void)
+{
+	int ret;
+
+	ret = platform_device_register(&vimc_pdev);
+	if (ret) {
+		dev_err(&vimc_pdev.dev,
+			"platform device registration failed (err=%d)\n", ret);
+		return ret;
+	}
+
+	ret = platform_driver_register(&vimc_pdrv);
+	if (ret) {
+		dev_err(&vimc_pdev.dev,
+			"platform driver registration failed (err=%d)\n", ret);
+
+		platform_device_unregister(&vimc_pdev);
+	}
+
+	return ret;
+}
+
+static void __exit vimc_exit(void)
+{
+	platform_driver_unregister(&vimc_pdrv);
+
+	platform_device_unregister(&vimc_pdev);
+}
+
+module_init(vimc_init);
+module_exit(vimc_exit);
+
+MODULE_DESCRIPTION("Virtual Media Controller Driver (VIMC)");
+MODULE_AUTHOR("Helen Fornazier <helen.fornazier@gmail.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/media/platform/vimc/vimc-core.h b/drivers/media/platform/vimc/vimc-core.h
new file mode 100644
index 0000000..be05469
--- /dev/null
+++ b/drivers/media/platform/vimc/vimc-core.h
@@ -0,0 +1,55 @@ 
+/*
+ * vimc-core.h Virtual Media Controller Driver
+ *
+ * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _VIMC_CORE_H_
+#define _VIMC_CORE_H_
+
+#include <media/v4l2-device.h>
+
+/* Struct which matches the MEDIA_BUS_FMT_ codes with the corresponding
+ * V4L2_PIX_FMT_ fourcc pixelformat and its bytes per pixel (bpp) */
+struct vimc_pix_map {
+	unsigned int code;
+	unsigned int bpp;
+	u32 pixelformat;
+};
+extern const struct vimc_pix_map vimc_pix_map_list[];
+
+struct vimc_ent_device {
+	struct media_entity *ent;
+	struct media_pad *pads;
+	void (*destroy)(struct vimc_ent_device *);
+	void (*process_frame)(struct vimc_ent_device *ved,
+			      struct media_pad *sink, const void *frame);
+};
+
+int vimc_propagate_frame(struct device *dev,
+			 struct media_pad *src, const void *frame);
+
+/* Helper functions to allocate/initialize pads and free them */
+struct media_pad *vimc_pads_init(u16 num_pads,
+				 const unsigned long *pads_flag);
+static inline void vimc_pads_cleanup(struct media_pad *pads)
+{
+	kfree(pads);
+}
+
+const struct vimc_pix_map *vimc_pix_map_by_code(u32 code);
+
+const struct vimc_pix_map *vimc_pix_map_by_pixelformat(u32 pixelformat);
+
+#endif
diff --git a/drivers/media/platform/vimc/vimc-sensor.c b/drivers/media/platform/vimc/vimc-sensor.c
new file mode 100644
index 0000000..ae70b9e
--- /dev/null
+++ b/drivers/media/platform/vimc/vimc-sensor.c
@@ -0,0 +1,277 @@ 
+/*
+ * vimc-sensor.c Virtual Media Controller Driver
+ *
+ * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/freezer.h>
+#include <linux/vmalloc.h>
+#include <linux/v4l2-mediabus.h>
+#include <media/v4l2-subdev.h>
+
+#include "vimc-sensor.h"
+
+struct vimc_sen_device {
+	struct vimc_ent_device ved;
+	struct v4l2_subdev sd;
+	struct v4l2_device *v4l2_dev;
+	struct device *dev;
+	struct task_struct *kthread_sen;
+	u8 *frame;
+	/* The active format */
+	struct v4l2_mbus_framefmt mbus_format;
+	int frame_size;
+};
+
+static int vimc_sen_enum_mbus_code(struct v4l2_subdev *sd,
+				   struct v4l2_subdev_pad_config *cfg,
+				   struct v4l2_subdev_mbus_code_enum *code)
+{
+	struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
+
+	/* Check if it is a valid pad */
+	if (code->pad >= vsen->sd.entity.num_pads)
+		return -EINVAL;
+
+	code->code = vsen->mbus_format.code;
+
+	return 0;
+}
+
+static int vimc_sen_enum_frame_size(struct v4l2_subdev *sd,
+				    struct v4l2_subdev_pad_config *cfg,
+				    struct v4l2_subdev_frame_size_enum *fse)
+{
+	struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
+
+	/* Check if it is a valid pad */
+	if (fse->pad >= vsen->sd.entity.num_pads ||
+	    !(vsen->sd.entity.pads[fse->pad].flags & MEDIA_PAD_FL_SOURCE))
+		return -EINVAL;
+
+	/* TODO: Add support to other formats */
+	if (fse->index)
+		return -EINVAL;
+
+	/* TODO: Add support for other codes */
+	if (fse->code != vsen->mbus_format.code)
+		return -EINVAL;
+
+	fse->min_width = vsen->mbus_format.width;
+	fse->max_width = vsen->mbus_format.width;
+	fse->min_height = vsen->mbus_format.height;
+	fse->max_height = vsen->mbus_format.height;
+
+	return 0;
+}
+
+static int vimc_sen_get_fmt(struct v4l2_subdev *sd,
+			    struct v4l2_subdev_pad_config *cfg,
+			    struct v4l2_subdev_format *format)
+{
+	struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
+
+	format->format = vsen->mbus_format;
+
+	return 0;
+}
+
+static const struct v4l2_subdev_pad_ops vimc_sen_pad_ops = {
+	.enum_mbus_code		= vimc_sen_enum_mbus_code,
+	.enum_frame_size	= vimc_sen_enum_frame_size,
+	.get_fmt		= vimc_sen_get_fmt,
+	/* TODO: Add support to other formats */
+	.set_fmt		= vimc_sen_get_fmt,
+};
+
+/* media operations */
+static const struct media_entity_operations vimc_sen_mops = {
+	.link_validate = v4l2_subdev_link_validate,
+};
+
+static int vimc_thread_sen(void *data)
+{
+	unsigned int i;
+	struct vimc_sen_device *vsen = data;
+
+	set_freezable();
+
+	for (;;) {
+		try_to_freeze();
+		if (kthread_should_stop())
+			break;
+
+		memset(vsen->frame, 100, vsen->frame_size);
+
+		/* Send the frame to all source pads */
+		for (i = 0; i < vsen->sd.entity.num_pads; i++)
+			if (vsen->sd.entity.pads[i].flags & MEDIA_PAD_FL_SOURCE)
+				vimc_propagate_frame(vsen->dev,
+						     &vsen->sd.entity.pads[i],
+						     vsen->frame);
+
+		/* Wait one second */
+		schedule_timeout_interruptible(HZ);
+	}
+
+	return 0;
+}
+
+static int vimc_sen_s_stream(struct v4l2_subdev *sd, int enable)
+{
+	int ret;
+	struct vimc_sen_device *vsen = v4l2_get_subdevdata(sd);
+
+	if (enable) {
+		const struct vimc_pix_map *vpix;
+
+		if (vsen->kthread_sen)
+			return -EINVAL;
+
+		/* Calculate the frame size */
+		vpix = vimc_pix_map_by_code(vsen->mbus_format.code);
+		/* This should never be NULL, as we won't allow any format
+		 * other then the ones in the vimc_pix_map_list table */
+		BUG_ON(!vpix);
+		vsen->frame_size = vsen->mbus_format.width * vpix->bpp *
+				   vsen->mbus_format.height;
+
+		/* Allocate the frame buffer. Use vmalloc to be able to
+		 * allocate a large amount of memory*/
+		vsen->frame = vmalloc(vsen->frame_size);
+		if (!vsen->frame)
+			return -ENOMEM;
+
+		/* Initialize the image generator thread */
+		vsen->kthread_sen = kthread_run(vimc_thread_sen, vsen,
+						"%s-sen", vsen->v4l2_dev->name);
+		if (IS_ERR(vsen->kthread_sen)) {
+			v4l2_err(vsen->v4l2_dev, "kernel_thread() failed\n");
+			vfree(vsen->frame);
+			vsen->frame = NULL;
+			return PTR_ERR(vsen->kthread_sen);
+		}
+	} else {
+		if (!vsen->kthread_sen)
+			return -EINVAL;
+
+		/* Stop image generator */
+		ret = kthread_stop(vsen->kthread_sen);
+		vsen->kthread_sen = NULL;
+
+		vfree(vsen->frame);
+		vsen->frame = NULL;
+		return ret;
+	}
+
+	return 0;
+}
+
+struct v4l2_subdev_video_ops vimc_sen_video_ops = {
+	.s_stream = vimc_sen_s_stream,
+};
+
+static const struct v4l2_subdev_ops vimc_sen_ops = {
+	.pad = &vimc_sen_pad_ops,
+	.video = &vimc_sen_video_ops,
+};
+
+static void vimc_sen_destroy(struct vimc_ent_device *ved)
+{
+	struct vimc_sen_device *vsen = container_of(ved,
+						struct vimc_sen_device, ved);
+
+	media_entity_cleanup(ved->ent);
+	v4l2_device_unregister_subdev(&vsen->sd);
+	kfree(vsen);
+}
+
+struct vimc_ent_device *vimc_sen_create(struct v4l2_device *v4l2_dev,
+					const char *const name,
+					u16 num_pads,
+					const unsigned long *pads_flag)
+{
+	int ret;
+	struct vimc_sen_device *vsen;
+
+	if (!v4l2_dev || !v4l2_dev->dev || !name || (num_pads && !pads_flag))
+		return ERR_PTR(-EINVAL);
+
+	/* Allocate the vsen struct */
+	vsen = kzalloc(sizeof(*vsen), GFP_KERNEL);
+	if (!vsen)
+		return ERR_PTR(-ENOMEM);
+
+	/* Link the vimc_sen_device struct with the v4l2 parent */
+	vsen->v4l2_dev = v4l2_dev;
+	/* Link the vimc_sen_device struct with the dev parent */
+	vsen->dev = v4l2_dev->dev;
+
+	/* Allocate the pads */
+	vsen->ved.pads = vimc_pads_init(num_pads, pads_flag);
+	if (IS_ERR(vsen->ved.pads)) {
+		ret = PTR_ERR(vsen->ved.pads);
+		goto err_free_vsen;
+	}
+
+	/* Initialize the media entity */
+	vsen->sd.entity.name = name;
+	vsen->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
+	ret = media_entity_pads_init(&vsen->sd.entity,
+				     num_pads, vsen->ved.pads);
+	if (ret)
+		goto err_clean_pads;
+
+	/* Set the active frame format (this is hardcoded for now) */
+	vsen->mbus_format.width = 640;
+	vsen->mbus_format.height = 480;
+	vsen->mbus_format.code = MEDIA_BUS_FMT_RGB888_1X24;
+	vsen->mbus_format.field = V4L2_FIELD_NONE;
+	vsen->mbus_format.colorspace = V4L2_COLORSPACE_SRGB;
+	vsen->mbus_format.quantization = V4L2_QUANTIZATION_FULL_RANGE;
+	vsen->mbus_format.xfer_func = V4L2_XFER_FUNC_SRGB;
+
+	/* Fill the vimc_ent_device struct */
+	vsen->ved.destroy = vimc_sen_destroy;
+	vsen->ved.ent = &vsen->sd.entity;
+
+	/* Initialize the subdev */
+	v4l2_subdev_init(&vsen->sd, &vimc_sen_ops);
+	vsen->sd.entity.ops = &vimc_sen_mops;
+	vsen->sd.owner = THIS_MODULE;
+	strlcpy(vsen->sd.name, name, sizeof(vsen->sd.name));
+	v4l2_set_subdevdata(&vsen->sd, vsen);
+
+	/* Expose this subdev to user space */
+	vsen->sd.flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
+
+	/* Register the subdev with the v4l2 and the media framework */
+	ret = v4l2_device_register_subdev(vsen->v4l2_dev, &vsen->sd);
+	if (ret) {
+		dev_err(vsen->dev,
+			"subdev register failed (err=%d)\n", ret);
+		goto err_clean_m_ent;
+	}
+
+	return &vsen->ved;
+
+err_clean_m_ent:
+	media_entity_cleanup(&vsen->sd.entity);
+err_clean_pads:
+	vimc_pads_cleanup(vsen->ved.pads);
+err_free_vsen:
+	kfree(vsen);
+
+	return ERR_PTR(ret);
+}
diff --git a/drivers/media/platform/vimc/vimc-sensor.h b/drivers/media/platform/vimc/vimc-sensor.h
new file mode 100644
index 0000000..67b7e07
--- /dev/null
+++ b/drivers/media/platform/vimc/vimc-sensor.h
@@ -0,0 +1,28 @@ 
+/*
+ * vimc-sensor.h Virtual Media Controller Driver
+ *
+ * Copyright (C) 2015 Helen Fornazier <helen.fornazier@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef _VIMC_SENSOR_H_
+#define _VIMC_SENSOR_H_
+
+#include "vimc-core.h"
+
+struct vimc_ent_device *vimc_sen_create(struct v4l2_device *v4l2_dev,
+					const char *const name,
+					u16 num_pads,
+					const unsigned long *pads_flag);
+
+#endif