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.fornaz...@gmail.com>

---

The Virtual Media Controller is meant to provide a test tool which simulates a 
configurable video pipeline exposing
the configuration of its individual nodes (such as sensors, debayers, scalers, 
inputs, outputs) throught the subdevice API.

This first version generates a grey image with a fixed format within a thread 
in the sensor, but it will be integrated with
the Test Pattern Generator from the Vivid driver in the future.

For more information: http://kernelnewbies.org/LaurentPinchart

The patch is based on 'media/master' branch and available at
        https://github.com/helen-fornazier/opw-staging vmc/review/video-pipe

Changes since v1:
- Rename vmc to vimc
- Alignement adjustments
- Remove extra blank line in vimc Makefile
- Implement s_input in one line with return i ? -EINVAL : 0;
- Remove s_fmt_vid_cap and try_fmt_vid_cap, plug g_fmt_vid_cap directly
- Remove set_fmt  in vimc-sensor.c and plug get_fmt directly
- Reorder paramenters declaration in vimc_cap_start_streaming
- Fix typos irs-> isr, its->it's
- Remove obsolete comment
- Register the video device just before returning from vimc_cap_create
- Register the subdevice device just before returning from vimc_sen_create
- In vimc-sensor.c file, rename declared structure with prefix vimc_sd_to 
vimc_sen_
- Remove vimc_cap_device/vimc_sen_device struct declaration from headers
- Remove vimc_cap_destroy/vimc_sen_destroy functions from headers and
  declare them as static (they are already acessible by a pointer in the
  struct returned in the create function)
- Rename vimc_pix_fmt_map{_list} to vimc_pix_map{_list}, shorter name
  because it will have other maps used by the debayer for example that may
  be called vimc_dep_pix_map{_list} and vimc_dep_pix_fmt_map{_list} is too big
- Bug fix: check if stream is active in process frame function, otherwise the 
frame may propagate to non active nodes
- Add node name in dev_dbg print

 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 | 535 ++++++++++++++++++++++++++
 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, 1530 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 f6bed19..220bb78 100644
--- a/drivers/media/platform/Kconfig
+++ b/drivers/media/platform/Kconfig
@@ -268,6 +268,8 @@ 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 114f9ab..50e2f86 100644
--- a/drivers/media/platform/Makefile
+++ b/drivers/media/platform/Makefile
@@ -13,6 +13,7 @@ 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..161ddc9
--- /dev/null
+++ b/drivers/media/platform/vimc/vimc-capture.c
@@ -0,0 +1,535 @@
+/*
+ * vimc-capture.c Virtual Media Controller Driver
+ *
+ * Copyright (C) 2015 Helen Fornazier <helen.fornaz...@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 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_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 just 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 just have one input */
+       *i = 0;
+       return 0;
+}
+
+static int vimc_cap_s_input(struct file *file, void *priv, unsigned int i)
+{
+       /* We just 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 just 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, 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 ||
+           media_entity_type(pad->entity) != MEDIA_ENT_T_V4L2_SUBDEV)
+               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, NULL);
+       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)
+{
+       struct vimc_cap_device *vcap = vb2_get_drv_priv(vb2->vb2_queue);
+       struct vimc_cap_buffer *buf = container_of(vb2,
+                                                  struct vimc_cap_buffer, vb2);
+
+       /* If the buffer doesn't have enough size, mark it as error */
+       if (vb2->v4l2_planes[0].length < vcap->format.sizeimage) {
+               vb2_buffer_done(vb2, 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,
+                               const struct v4l2_format *fmt,
+                               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] = fmt ? fmt->fmt.pix.sizeimage : 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 (link->source->entity->type != MEDIA_ENT_T_V4L2_SUBDEV)
+               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 form the list */
+       list_del(&vimc_buf->list);
+
+       spin_unlock(&vcap->qlock);
+
+       /* Fill the buffer */
+       v4l2_get_timestamp(&vimc_buf->vb2.v4l2_buf.timestamp);
+       vimc_buf->vb2.v4l2_buf.sequence = vcap->sequence++;
+       vimc_buf->vb2.v4l2_buf.field = vcap->format.field;
+
+       vbuf = vb2_plane_vaddr(&vimc_buf->vb2, 0);
+
+       memcpy(vbuf, frame, vcap->format.sizeimage);
+
+       /* Set it as ready */
+       vb2_set_plane_payload(&vimc_buf->vb2, 0, vcap->format.sizeimage);
+       vb2_buffer_done(&vimc_buf->vb2, 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 the v4l2 parent */
+       vcap->v4l2_dev = v4l2_dev;
+       /* Link the vimc_cap_device struct with the dev parent */
+       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.type = MEDIA_ENT_T_DEVNODE;
+       ret = media_entity_init(&vcap->vdev.entity, num_pads,
+                               vcap->ved.pads, num_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.fornaz...@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..3ef9b51
--- /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.fornaz...@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)
+{
+       unsigned int i;
+       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 */
+       for (i = 0; i < src->entity->num_links; i++) {
+               link = &src->entity->links[i];
+
+               if (link->source == src &&
+                   (link->flags & MEDIA_LNK_FL_ENABLED)) {
+                       struct vimc_ent_device *ved;
+
+                       ved = vimc->ved[link->sink->entity->id - 1];
+                       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);
+
+       /* 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->type = MEDIA_ENT_T_DEVNODE;
+       ret = media_entity_init(ved->ent, num_pads, ved->pads, num_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;
+       }
+
+       /* Fill pads/entities structures and initialize entity */
+       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;
+               }
+       }
+
+       /* 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_entity_create_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;
+
+       /* Set the mdev model name */
+       strlcpy(vimc->mdev.model, VIMC_MDEV_MODEL_NAME,
+               sizeof(vimc->mdev.model));
+
+       /* Link dev with the media device. */
+       vimc->mdev.dev = &pdev->dev;
+
+       /* 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.fornaz...@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.fornaz...@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..d613792
--- /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.fornaz...@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.type = MEDIA_ENT_T_V4L2_SUBDEV;
+       ret = media_entity_init(&vsen->sd.entity, num_pads,
+                               vsen->ved.pads, num_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.fornaz...@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

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