text: // SPDX-License-Identifier: GPL-2.0-or-later
  /*
   * vimc-capture.c Virtual Media Controller Driver
   *
   * Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com>
   */
  
  #include <media/v4l2-ioctl.h>
  #include <media/videobuf2-core.h>
  #include <media/videobuf2-dma-contig.h>
  #include <media/videobuf2-vmalloc.h>
  
  #include "vimc-common.h"
  #include "vimc-streamer.h"
  
  struct vimc_cap_device {
  	struct vimc_ent_device ved;
  	struct video_device vdev;
  	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_stream stream;
  	struct media_pad pad;
  };
  
  static const struct v4l2_pix_format fmt_default = {
  	.width = 640,
  	.height = 480,
  	.pixelformat = V4L2_PIX_FMT_RGB24,
  	.field = V4L2_FIELD_NONE,
  	.colorspace = V4L2_COLORSPACE_SRGB,
  };
  
  struct vimc_cap_buffer {
  	/*
  	 * struct vb2_v4l2_buffer must be the first element
  	 * the videobuf2 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)
  {
  	strscpy(cap->driver, VIMC_PDEV_NAME, sizeof(cap->driver));
  	strscpy(cap->card, KBUILD_MODNAME, sizeof(cap->card));
  	snprintf(cap->bus_info, sizeof(cap->bus_info),
  		 "platform:%s", VIMC_PDEV_NAME);
  
  	return 0;
  }
  
  static void vimc_cap_get_format(struct vimc_ent_device *ved,
  				struct v4l2_pix_format *fmt)
  {
  	struct vimc_cap_device *vcap = container_of(ved, struct vimc_cap_device,
  						    ved);
  
  	*fmt = vcap->format;
  }
  
  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_try_fmt_vid_cap(struct file *file, void *priv,
  				    struct v4l2_format *f)
  {
  	struct v4l2_pix_format *format = &f->fmt.pix;
  	const struct vimc_pix_map *vpix;
  
  	format->width = clamp_t(u32, format->width, VIMC_FRAME_MIN_WIDTH,
  				VIMC_FRAME_MAX_WIDTH) & ~1;
  	format->height = clamp_t(u32, format->height, VIMC_FRAME_MIN_HEIGHT,
  				 VIMC_FRAME_MAX_HEIGHT) & ~1;
  
  	/* Don't accept a pixelformat that is not on the table */
  	vpix = vimc_pix_map_by_pixelformat(format->pixelformat);
  	if (!vpix) {
  		format->pixelformat = fmt_default.pixelformat;
  		vpix = vimc_pix_map_by_pixelformat(format->pixelformat);
  	}
  	/* TODO: Add support for custom bytesperline values */
  	format->bytesperline = format->width * vpix->bpp;
  	format->sizeimage = format->bytesperline * format->height;
  
  	if (format->field == V4L2_FIELD_ANY)
  		format->field = fmt_default.field;
  
  	vimc_colorimetry_clamp(format);
  
  	if (format->colorspace == V4L2_COLORSPACE_DEFAULT)
  		format->colorspace = fmt_default.colorspace;
  
  	return 0;
  }
  
  static int vimc_cap_s_fmt_vid_cap(struct file *file, void *priv,
  				  struct v4l2_format *f)
  {
  	struct vimc_cap_device *vcap = video_drvdata(file);
  	int ret;
  
  	/* Do not change the format while stream is on */
  	if (vb2_is_busy(&vcap->queue))
  		return -EBUSY;
  
  	ret = vimc_cap_try_fmt_vid_cap(file, priv, f);
  	if (ret)
  		return ret;
  
  	dev_dbg(vcap->ved.dev, "%s: format update: "
  		"old:%dx%d (0x%x, %d, %d, %d, %d) "
  		"new:%dx%d (0x%x, %d, %d, %d, %d)\n", vcap->vdev.name,
  		/* old */
  		vcap->format.width, vcap->format.height,
  		vcap->format.pixelformat, vcap->format.colorspace,
  		vcap->format.quantization, vcap->format.xfer_func,
  		vcap->format.ycbcr_enc,
  		/* new */
  		f->fmt.pix.width, f->fmt.pix.height,
  		f->fmt.pix.pixelformat,	f->fmt.pix.colorspace,
  		f->fmt.pix.quantization, f->fmt.pix.xfer_func,
  		f->fmt.pix.ycbcr_enc);
  
  	vcap->format = f->fmt.pix;
  
  	return 0;
  }
  
  static int vimc_cap_enum_fmt_vid_cap(struct file *file, void *priv,
  				     struct v4l2_fmtdesc *f)
  {
  	const struct vimc_pix_map *vpix;
  
  	if (f->mbus_code) {
  		if (f->index > 0)
  			return -EINVAL;
  
  		vpix = vimc_pix_map_by_code(f->mbus_code);
  	} else {
  		vpix = vimc_pix_map_by_index(f->index);
  	}
  
  	if (!vpix)
  		return -EINVAL;
  
  	f->pixelformat = vpix->pixelformat;
  
  	return 0;
  }
  
  static int vimc_cap_enum_framesizes(struct file *file, void *fh,
  				    struct v4l2_frmsizeenum *fsize)
  {
  	const struct vimc_pix_map *vpix;
  
  	if (fsize->index)
  		return -EINVAL;
  
  	/* Only accept code in the pix map table */
  	vpix = vimc_pix_map_by_code(fsize->pixel_format);
  	if (!vpix)
  		return -EINVAL;
  
  	fsize->type = V4L2_FRMSIZE_TYPE_CONTINUOUS;
  	fsize->stepwise.min_width = VIMC_FRAME_MIN_WIDTH;
  	fsize->stepwise.max_width = VIMC_FRAME_MAX_WIDTH;
  	fsize->stepwise.min_height = VIMC_FRAME_MIN_HEIGHT;
  	fsize->stepwise.max_height = VIMC_FRAME_MAX_HEIGHT;
  	fsize->stepwise.step_width = 1;
  	fsize->stepwise.step_height = 1;
  
  	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_g_fmt_vid_cap = vimc_cap_g_fmt_vid_cap,
  	.vidioc_s_fmt_vid_cap = vimc_cap_s_fmt_vid_cap,
  	.vidioc_try_fmt_vid_cap = vimc_cap_try_fmt_vid_cap,
  	.vidioc_enum_fmt_vid_cap = vimc_cap_enum_fmt_vid_cap,
  	.vidioc_enum_framesizes = vimc_cap_enum_framesizes,
  
  	.vidioc_reqbufs = vb2_ioctl_reqbufs,
  	.vidioc_create_bufs = vb2_ioctl_create_bufs,
  	.vidioc_prepare_buf = vb2_ioctl_prepare_buf,
  	.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) {
  		list_del(&vbuf->list);
  		vb2_buffer_done(&vbuf->vb2.vb2_buf, state);
  	}
  
  	spin_unlock(&vcap->qlock);
  }
  
  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 = &vcap->vdev.entity;
  	int ret;
  
  	vcap->sequence = 0;
  
  	/* Start the media pipeline */
  	ret = media_pipeline_start(entity, &vcap->stream.pipe);
  	if (ret) {
  		vimc_cap_return_all_buffers(vcap, VB2_BUF_STATE_QUEUED);
  		return ret;
  	}
  
  	ret = vimc_streamer_s_stream(&vcap->stream, &vcap->ved, 1);
  	if (ret) {
  		media_pipeline_stop(entity);
  		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);
  
  	vimc_streamer_s_stream(&vcap->stream, &vcap->ved, 0);
  
  	/* Stop the media pipeline */
  	media_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);
  
  	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[],
  				struct device *alloc_devs[])
  {
  	struct vimc_cap_device *vcap = vb2_get_drv_priv(vq);
  
  	if (*nplanes)
  		return sizes[0] < vcap->format.sizeimage ? -EINVAL : 0;
  	/* We don't support multiplanes for now */
  	*nplanes = 1;
  	sizes[0] = vcap->format.sizeimage;
  
  	return 0;
  }
  
  static int vimc_cap_buffer_prepare(struct vb2_buffer *vb)
  {
  	struct vimc_cap_device *vcap = vb2_get_drv_priv(vb->vb2_queue);
  	unsigned long size = vcap->format.sizeimage;
  
  	if (vb2_plane_size(vb, 0) < size) {
  		dev_err(vcap->ved.dev, "%s: buffer too small (%lu < %lu)\n",
  			vcap->vdev.name, vb2_plane_size(vb, 0), size);
  		return -EINVAL;
  	}
  	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,
  	.buf_prepare		= vimc_cap_buffer_prepare,
  	/*
  	 * 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,
  };
  
  static const struct media_entity_operations vimc_cap_mops = {
  	.link_validate		= vimc_vdev_link_validate,
  };
  
  static void vimc_cap_release(struct vimc_ent_device *ved)
  {
  	struct vimc_cap_device *vcap =
  		container_of(ved, struct vimc_cap_device, ved);
  
  	media_entity_cleanup(vcap->ved.ent);
  	kfree(vcap);
  }
  
  static void vimc_cap_unregister(struct vimc_ent_device *ved)
  {
  	struct vimc_cap_device *vcap =
  		container_of(ved, struct vimc_cap_device, ved);
  
  	vb2_video_unregister_device(&vcap->vdev);
  }
  
  static void *vimc_cap_process_frame(struct vimc_ent_device *ved,
  				    const void *frame)
  {
  	struct vimc_cap_device *vcap = container_of(ved, struct vimc_cap_device,
  						    ved);
  	struct vimc_cap_buffer *vimc_buf;
  	void *vbuf;
  
  	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 ERR_PTR(-EAGAIN);
  	}
  
  	/* 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);
  	return NULL;
  }
  
  static struct vimc_ent_device *vimc_cap_add(struct vimc_device *vimc,
  					    const char *vcfg_name)
  {
  	struct v4l2_device *v4l2_dev = &vimc->v4l2_dev;
  	const struct vimc_pix_map *vpix;
  	struct vimc_cap_device *vcap;
  	struct video_device *vdev;
  	struct vb2_queue *q;
  	int ret;
  
  	/* Allocate the vimc_cap_device struct */
  	vcap = kzalloc(sizeof(*vcap), GFP_KERNEL);
  	if (!vcap)
  		return ERR_PTR(-ENOMEM);
  
  	/* Initialize the media entity */
  	vcap->vdev.entity.name = vcfg_name;
  	vcap->vdev.entity.function = MEDIA_ENT_F_IO_V4L;
  	vcap->pad.flags = MEDIA_PAD_FL_SINK;
  	ret = media_entity_pads_init(&vcap->vdev.entity,
  				     1, &vcap->pad);
  	if (ret)
  		goto err_free_vcap;
  
  	/* 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;
  	if (vimc_allocator == VIMC_ALLOCATOR_VMALLOC)
  		q->io_modes |= VB2_USERPTR;
  	q->drv_priv = vcap;
  	q->buf_struct_size = sizeof(struct vimc_cap_buffer);
  	q->ops = &vimc_cap_qops;
  	q->mem_ops = vimc_allocator == VIMC_ALLOCATOR_DMA_CONTIG
  		   ? &vb2_dma_contig_memops : &vb2_vmalloc_memops;
  	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
  	q->min_buffers_needed = 2;
  	q->lock = &vcap->lock;
  	q->dev = v4l2_dev->dev;
  
  	ret = vb2_queue_init(q);
  	if (ret) {
  		dev_err(vimc->mdev.dev, "%s: vb2 queue init failed (err=%d)\n",
  			vcfg_name, ret);
  		goto err_clean_m_ent;
  	}
  
  	/* Initialize buffer list and its lock */
  	INIT_LIST_HEAD(&vcap->buf_list);
  	spin_lock_init(&vcap->qlock);
  
  	/* Set default frame format */
  	vcap->format = fmt_default;
  	vpix = vimc_pix_map_by_pixelformat(vcap->format.pixelformat);
  	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.ent = &vcap->vdev.entity;
  	vcap->ved.process_frame = vimc_cap_process_frame;
  	vcap->ved.vdev_get_format = vimc_cap_get_format;
  	vcap->ved.dev = vimc->mdev.dev;
  
  	/* Initialize the video_device struct */
  	vdev = &vcap->vdev;
  	vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING
  			  | V4L2_CAP_IO_MC;
  	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 = v4l2_dev;
  	vdev->vfl_dir = VFL_DIR_RX;
  	strscpy(vdev->name, vcfg_name, sizeof(vdev->name));
  	video_set_drvdata(vdev, &vcap->ved);
  
  	/* Register the video_device with the v4l2 and the media framework */
  	ret = video_register_device(vdev, VFL_TYPE_VIDEO, -1);
  	if (ret) {
  		dev_err(vimc->mdev.dev, "%s: video register failed (err=%d)\n",
  			vcap->vdev.name, ret);
  		goto err_clean_m_ent;
  	}
  
  	return &vcap->ved;
  
  err_clean_m_ent:
  	media_entity_cleanup(&vcap->vdev.entity);
  err_free_vcap:
  	kfree(vcap);
  
  	return ERR_PTR(ret);
  }
  
  struct vimc_ent_type vimc_cap_type = {
  	.add = vimc_cap_add,
  	.unregister = vimc_cap_unregister,
  	.release = vimc_cap_release
  };
  