text: // SPDX-License-Identifier: GPL-2.0
  /*
   * video.c - V4L2 component for Mostcore
   *
   * Copyright (C) 2015, Microchip Technology Germany II GmbH & Co. KG
   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/init.h>
  #include <linux/device.h>
  #include <linux/suspend.h>
  #include <linux/videodev2.h>
  #include <linux/mutex.h>
  #include <media/v4l2-common.h>
  #include <media/v4l2-ioctl.h>
  #include <media/v4l2-event.h>
  #include <media/v4l2-device.h>
  #include <media/v4l2-ctrls.h>
  #include <media/v4l2-fh.h>
  #include <linux/most.h>
  
  #define V4L2_CMP_MAX_INPUT  1
  
  static struct most_component comp;
  
  struct most_video_dev {
  	struct most_interface *iface;
  	int ch_idx;
  	struct list_head list;
  	bool mute;
  
  	struct list_head pending_mbos;
  	spinlock_t list_lock;
  
  	struct v4l2_device v4l2_dev;
  	atomic_t access_ref;
  	struct video_device *vdev;
  	unsigned int ctrl_input;
  
  	struct mutex lock;
  
  	wait_queue_head_t wait_data;
  };
  
  struct comp_fh {
  	/* must be the first field of this struct! */
  	struct v4l2_fh fh;
  	struct most_video_dev *mdev;
  	u32 offs;
  };
  
  static struct list_head video_devices = LIST_HEAD_INIT(video_devices);
  static DEFINE_SPINLOCK(list_lock);
  
  static inline bool data_ready(struct most_video_dev *mdev)
  {
  	return !list_empty(&mdev->pending_mbos);
  }
  
  static inline struct mbo *get_top_mbo(struct most_video_dev *mdev)
  {
  	return list_first_entry(&mdev->pending_mbos, struct mbo, list);
  }
  
  static int comp_vdev_open(struct file *filp)
  {
  	int ret;
  	struct video_device *vdev = video_devdata(filp);
  	struct most_video_dev *mdev = video_drvdata(filp);
  	struct comp_fh *fh;
  
  	switch (vdev->vfl_type) {
  	case VFL_TYPE_VIDEO:
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	fh = kzalloc(sizeof(*fh), GFP_KERNEL);
  	if (!fh)
  		return -ENOMEM;
  
  	if (!atomic_inc_and_test(&mdev->access_ref)) {
  		v4l2_err(&mdev->v4l2_dev, "too many clients\n");
  		ret = -EBUSY;
  		goto err_dec;
  	}
  
  	fh->mdev = mdev;
  	v4l2_fh_init(&fh->fh, vdev);
  	filp->private_data = fh;
  
  	v4l2_fh_add(&fh->fh);
  
  	ret = most_start_channel(mdev->iface, mdev->ch_idx, &comp);
  	if (ret) {
  		v4l2_err(&mdev->v4l2_dev, "most_start_channel() failed\n");
  		goto err_rm;
  	}
  
  	return 0;
  
  err_rm:
  	v4l2_fh_del(&fh->fh);
  	v4l2_fh_exit(&fh->fh);
  
  err_dec:
  	atomic_dec(&mdev->access_ref);
  	kfree(fh);
  	return ret;
  }
  
  static int comp_vdev_close(struct file *filp)
  {
  	struct comp_fh *fh = filp->private_data;
  	struct most_video_dev *mdev = fh->mdev;
  	struct mbo *mbo, *tmp;
  
  	/*
  	 * We need to put MBOs back before we call most_stop_channel()
  	 * to deallocate MBOs.
  	 * From the other hand mostcore still calling rx_completion()
  	 * to deliver MBOs until most_stop_channel() is called.
  	 * Use mute to work around this issue.
  	 * This must be implemented in core.
  	 */
  
  	spin_lock_irq(&mdev->list_lock);
  	mdev->mute = true;
  	list_for_each_entry_safe(mbo, tmp, &mdev->pending_mbos, list) {
  		list_del(&mbo->list);
  		spin_unlock_irq(&mdev->list_lock);
  		most_put_mbo(mbo);
  		spin_lock_irq(&mdev->list_lock);
  	}
  	spin_unlock_irq(&mdev->list_lock);
  	most_stop_channel(mdev->iface, mdev->ch_idx, &comp);
  	mdev->mute = false;
  
  	v4l2_fh_del(&fh->fh);
  	v4l2_fh_exit(&fh->fh);
  
  	atomic_dec(&mdev->access_ref);
  	kfree(fh);
  	return 0;
  }
  
  static ssize_t comp_vdev_read(struct file *filp, char __user *buf,
  			      size_t count, loff_t *pos)
  {
  	struct comp_fh *fh = filp->private_data;
  	struct most_video_dev *mdev = fh->mdev;
  	int ret = 0;
  
  	if (*pos)
  		return -ESPIPE;
  
  	if (!mdev)
  		return -ENODEV;
  
  	/* wait for the first buffer */
  	if (!(filp->f_flags & O_NONBLOCK)) {
  		if (wait_event_interruptible(mdev->wait_data, data_ready(mdev)))
  			return -ERESTARTSYS;
  	}
  
  	if (!data_ready(mdev))
  		return -EAGAIN;
  
  	while (count > 0 && data_ready(mdev)) {
  		struct mbo *const mbo = get_top_mbo(mdev);
  		int const rem = mbo->processed_length - fh->offs;
  		int const cnt = rem < count ? rem : count;
  
  		if (copy_to_user(buf, mbo->virt_address + fh->offs, cnt)) {
  			v4l2_err(&mdev->v4l2_dev, "read: copy_to_user failed\n");
  			if (!ret)
  				ret = -EFAULT;
  			return ret;
  		}
  
  		fh->offs += cnt;
  		count -= cnt;
  		buf += cnt;
  		ret += cnt;
  
  		if (cnt >= rem) {
  			fh->offs = 0;
  			spin_lock_irq(&mdev->list_lock);
  			list_del(&mbo->list);
  			spin_unlock_irq(&mdev->list_lock);
  			most_put_mbo(mbo);
  		}
  	}
  	return ret;
  }
  
  static __poll_t comp_vdev_poll(struct file *filp, poll_table *wait)
  {
  	struct comp_fh *fh = filp->private_data;
  	struct most_video_dev *mdev = fh->mdev;
  	__poll_t mask = 0;
  
  	/* only wait if no data is available */
  	if (!data_ready(mdev))
  		poll_wait(filp, &mdev->wait_data, wait);
  	if (data_ready(mdev))
  		mask |= EPOLLIN | EPOLLRDNORM;
  
  	return mask;
  }
  
  static void comp_set_format_struct(struct v4l2_format *f)
  {
  	f->fmt.pix.width = 8;
  	f->fmt.pix.height = 8;
  	f->fmt.pix.pixelformat = V4L2_PIX_FMT_MPEG;
  	f->fmt.pix.bytesperline = 0;
  	f->fmt.pix.sizeimage = 188 * 2;
  	f->fmt.pix.colorspace = V4L2_COLORSPACE_REC709;
  	f->fmt.pix.field = V4L2_FIELD_NONE;
  	f->fmt.pix.priv = 0;
  }
  
  static int comp_set_format(struct most_video_dev *mdev, unsigned int cmd,
  			   struct v4l2_format *format)
  {
  	if (format->fmt.pix.pixelformat != V4L2_PIX_FMT_MPEG)
  		return -EINVAL;
  
  	if (cmd == VIDIOC_TRY_FMT)
  		return 0;
  
  	comp_set_format_struct(format);
  
  	return 0;
  }
  
  static int vidioc_querycap(struct file *file, void *priv,
  			   struct v4l2_capability *cap)
  {
  	struct comp_fh *fh = priv;
  	struct most_video_dev *mdev = fh->mdev;
  
  	strscpy(cap->driver, "v4l2_component", sizeof(cap->driver));
  	strscpy(cap->card, "MOST", sizeof(cap->card));
  	snprintf(cap->bus_info, sizeof(cap->bus_info),
  		 "%s", mdev->iface->description);
  	return 0;
  }
  
  static int vidioc_enum_fmt_vid_cap(struct file *file, void *priv,
  				   struct v4l2_fmtdesc *f)
  {
  	if (f->index)
  		return -EINVAL;
  
  	strscpy(f->description, "MPEG", sizeof(f->description));
  	f->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  	f->flags = V4L2_FMT_FLAG_COMPRESSED;
  	f->pixelformat = V4L2_PIX_FMT_MPEG;
  
  	return 0;
  }
  
  static int vidioc_g_fmt_vid_cap(struct file *file, void *priv,
  				struct v4l2_format *f)
  {
  	comp_set_format_struct(f);
  	return 0;
  }
  
  static int vidioc_try_fmt_vid_cap(struct file *file, void *priv,
  				  struct v4l2_format *f)
  {
  	struct comp_fh *fh = priv;
  	struct most_video_dev *mdev = fh->mdev;
  
  	return comp_set_format(mdev, VIDIOC_TRY_FMT, f);
  }
  
  static int vidioc_s_fmt_vid_cap(struct file *file, void *priv,
  				struct v4l2_format *f)
  {
  	struct comp_fh *fh = priv;
  	struct most_video_dev *mdev = fh->mdev;
  
  	return comp_set_format(mdev, VIDIOC_S_FMT, f);
  }
  
  static int vidioc_g_std(struct file *file, void *priv, v4l2_std_id *norm)
  {
  	*norm = V4L2_STD_UNKNOWN;
  	return 0;
  }
  
  static int vidioc_enum_input(struct file *file, void *priv,
  			     struct v4l2_input *input)
  {
  	struct comp_fh *fh = priv;
  	struct most_video_dev *mdev = fh->mdev;
  
  	if (input->index >= V4L2_CMP_MAX_INPUT)
  		return -EINVAL;
  
  	strscpy(input->name, "MOST Video", sizeof(input->name));
  	input->type |= V4L2_INPUT_TYPE_CAMERA;
  	input->audioset = 0;
  
  	input->std = mdev->vdev->tvnorms;
  
  	return 0;
  }
  
  static int vidioc_g_input(struct file *file, void *priv, unsigned int *i)
  {
  	struct comp_fh *fh = priv;
  	struct most_video_dev *mdev = fh->mdev;
  	*i = mdev->ctrl_input;
  	return 0;
  }
  
  static int vidioc_s_input(struct file *file, void *priv, unsigned int index)
  {
  	struct comp_fh *fh = priv;
  	struct most_video_dev *mdev = fh->mdev;
  
  	if (index >= V4L2_CMP_MAX_INPUT)
  		return -EINVAL;
  	mdev->ctrl_input = index;
  	return 0;
  }
  
  static const struct v4l2_file_operations comp_fops = {
  	.owner      = THIS_MODULE,
  	.open       = comp_vdev_open,
  	.release    = comp_vdev_close,
  	.read       = comp_vdev_read,
  	.poll       = comp_vdev_poll,
  	.unlocked_ioctl = video_ioctl2,
  };
  
  static const struct v4l2_ioctl_ops video_ioctl_ops = {
  	.vidioc_querycap            = vidioc_querycap,
  	.vidioc_enum_fmt_vid_cap    = vidioc_enum_fmt_vid_cap,
  	.vidioc_g_fmt_vid_cap       = vidioc_g_fmt_vid_cap,
  	.vidioc_try_fmt_vid_cap     = vidioc_try_fmt_vid_cap,
  	.vidioc_s_fmt_vid_cap       = vidioc_s_fmt_vid_cap,
  	.vidioc_g_std               = vidioc_g_std,
  	.vidioc_enum_input          = vidioc_enum_input,
  	.vidioc_g_input             = vidioc_g_input,
  	.vidioc_s_input             = vidioc_s_input,
  };
  
  static const struct video_device comp_videodev_template = {
  	.fops = &comp_fops,
  	.release = video_device_release,
  	.ioctl_ops = &video_ioctl_ops,
  	.tvnorms = V4L2_STD_UNKNOWN,
  	.device_caps = V4L2_CAP_READWRITE | V4L2_CAP_VIDEO_CAPTURE,
  };
  
  /**************************************************************************/
  
  static struct most_video_dev *get_comp_dev(
  	struct most_interface *iface, int channel_idx)
  {
  	struct most_video_dev *mdev;
  	unsigned long flags;
  
  	spin_lock_irqsave(&list_lock, flags);
  	list_for_each_entry(mdev, &video_devices, list) {
  		if (mdev->iface == iface && mdev->ch_idx == channel_idx) {
  			spin_unlock_irqrestore(&list_lock, flags);
  			return mdev;
  		}
  	}
  	spin_unlock_irqrestore(&list_lock, flags);
  	return NULL;
  }
  
  static int comp_rx_data(struct mbo *mbo)
  {
  	unsigned long flags;
  	struct most_video_dev *mdev =
  		get_comp_dev(mbo->ifp, mbo->hdm_channel_id);
  
  	if (!mdev)
  		return -EIO;
  
  	spin_lock_irqsave(&mdev->list_lock, flags);
  	if (unlikely(mdev->mute)) {
  		spin_unlock_irqrestore(&mdev->list_lock, flags);
  		return -EIO;
  	}
  
  	list_add_tail(&mbo->list, &mdev->pending_mbos);
  	spin_unlock_irqrestore(&mdev->list_lock, flags);
  	wake_up_interruptible(&mdev->wait_data);
  	return 0;
  }
  
  static int comp_register_videodev(struct most_video_dev *mdev)
  {
  	int ret;
  
  	init_waitqueue_head(&mdev->wait_data);
  
  	/* allocate and fill v4l2 video struct */
  	mdev->vdev = video_device_alloc();
  	if (!mdev->vdev)
  		return -ENOMEM;
  
  	/* Fill the video capture device struct */
  	*mdev->vdev = comp_videodev_template;
  	mdev->vdev->v4l2_dev = &mdev->v4l2_dev;
  	mdev->vdev->lock = &mdev->lock;
  	snprintf(mdev->vdev->name, sizeof(mdev->vdev->name), "MOST: %s",
  		 mdev->v4l2_dev.name);
  
  	/* Register the v4l2 device */
  	video_set_drvdata(mdev->vdev, mdev);
  	ret = video_register_device(mdev->vdev, VFL_TYPE_VIDEO, -1);
  	if (ret) {
  		v4l2_err(&mdev->v4l2_dev, "video_register_device failed (%d)\n",
  			 ret);
  		video_device_release(mdev->vdev);
  	}
  
  	return ret;
  }
  
  static void comp_unregister_videodev(struct most_video_dev *mdev)
  {
  	video_unregister_device(mdev->vdev);
  }
  
  static void comp_v4l2_dev_release(struct v4l2_device *v4l2_dev)
  {
  	struct most_video_dev *mdev =
  		container_of(v4l2_dev, struct most_video_dev, v4l2_dev);
  
  	v4l2_device_unregister(v4l2_dev);
  	kfree(mdev);
  }
  
  static int comp_probe_channel(struct most_interface *iface, int channel_idx,
  			      struct most_channel_config *ccfg, char *name,
  			      char *args)
  {
  	int ret;
  	struct most_video_dev *mdev = get_comp_dev(iface, channel_idx);
  
  	if (mdev) {
  		pr_err("channel already linked\n");
  		return -EEXIST;
  	}
  
  	if (ccfg->direction != MOST_CH_RX) {
  		pr_err("wrong direction, expect rx\n");
  		return -EINVAL;
  	}
  
  	if (ccfg->data_type != MOST_CH_SYNC &&
  	    ccfg->data_type != MOST_CH_ISOC) {
  		pr_err("wrong channel type, expect sync or isoc\n");
  		return -EINVAL;
  	}
  
  	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
  	if (!mdev)
  		return -ENOMEM;
  
  	mutex_init(&mdev->lock);
  	atomic_set(&mdev->access_ref, -1);
  	spin_lock_init(&mdev->list_lock);
  	INIT_LIST_HEAD(&mdev->pending_mbos);
  	mdev->iface = iface;
  	mdev->ch_idx = channel_idx;
  	mdev->v4l2_dev.release = comp_v4l2_dev_release;
  
  	/* Create the v4l2_device */
  	strscpy(mdev->v4l2_dev.name, name, sizeof(mdev->v4l2_dev.name));
  	ret = v4l2_device_register(NULL, &mdev->v4l2_dev);
  	if (ret) {
  		pr_err("v4l2_device_register() failed\n");
  		kfree(mdev);
  		return ret;
  	}
  
  	ret = comp_register_videodev(mdev);
  	if (ret)
  		goto err_unreg;
  
  	spin_lock_irq(&list_lock);
  	list_add(&mdev->list, &video_devices);
  	spin_unlock_irq(&list_lock);
  	return 0;
  
  err_unreg:
  	v4l2_device_disconnect(&mdev->v4l2_dev);
  	v4l2_device_put(&mdev->v4l2_dev);
  	return ret;
  }
  
  static int comp_disconnect_channel(struct most_interface *iface,
  				   int channel_idx)
  {
  	struct most_video_dev *mdev = get_comp_dev(iface, channel_idx);
  
  	if (!mdev) {
  		pr_err("no such channel is linked\n");
  		return -ENOENT;
  	}
  
  	spin_lock_irq(&list_lock);
  	list_del(&mdev->list);
  	spin_unlock_irq(&list_lock);
  
  	comp_unregister_videodev(mdev);
  	v4l2_device_disconnect(&mdev->v4l2_dev);
  	v4l2_device_put(&mdev->v4l2_dev);
  	return 0;
  }
  
  static struct most_component comp = {
  	.mod = THIS_MODULE,
  	.name = "video",
  	.probe_channel = comp_probe_channel,
  	.disconnect_channel = comp_disconnect_channel,
  	.rx_completion = comp_rx_data,
  };
  
  static int __init comp_init(void)
  {
  	int err;
  
  	err = most_register_component(&comp);
  	if (err)
  		return err;
  	err = most_register_configfs_subsys(&comp);
  	if (err) {
  		most_deregister_component(&comp);
  		return err;
  	}
  	return 0;
  }
  
  static void __exit comp_exit(void)
  {
  	struct most_video_dev *mdev, *tmp;
  
  	/*
  	 * As the mostcore currently doesn't call disconnect_channel()
  	 * for linked channels while we call most_deregister_component()
  	 * we simulate this call here.
  	 * This must be fixed in core.
  	 */
  	spin_lock_irq(&list_lock);
  	list_for_each_entry_safe(mdev, tmp, &video_devices, list) {
  		list_del(&mdev->list);
  		spin_unlock_irq(&list_lock);
  
  		comp_unregister_videodev(mdev);
  		v4l2_device_disconnect(&mdev->v4l2_dev);
  		v4l2_device_put(&mdev->v4l2_dev);
  		spin_lock_irq(&list_lock);
  	}
  	spin_unlock_irq(&list_lock);
  
  	most_deregister_configfs_subsys(&comp);
  	most_deregister_component(&comp);
  	BUG_ON(!list_empty(&video_devices));
  }
  
  module_init(comp_init);
  module_exit(comp_exit);
  
  MODULE_DESCRIPTION("V4L2 Component Module for Mostcore");
  MODULE_AUTHOR("Andrey Shvetsov <andrey.shvetsov@k2l.de>");
  MODULE_LICENSE("GPL");
  