Staging: most: add MOST driver's aim-v4l2 module

This patch adds the aim-v4l2 module of the MOST driver to the kernel's
driver staging area. This module is part of the MOST driver and handles
user space interaction by means of V4L2.

This patch is needed in order to have access to MOST isochronous AVP data
through V4L2 devices.
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/most/Kconfig

@@ -19,4 +19,6 @@ source "drivers/staging/most/aim-network/Kconfig"
 
 source "drivers/staging/most/aim-sound/Kconfig"
 
+source "drivers/staging/most/aim-v4l2/Kconfig"
+
 endif

drivers/staging/most/Makefile

@@ -2,3 +2,4 @@ obj-$(CONFIG_MOSTCORE)	+= mostcore/
 obj-$(CONFIG_AIM_CDEV)	+= aim-cdev/
 obj-$(CONFIG_AIM_NETWORK)	+= aim-network/
 obj-$(CONFIG_AIM_SOUND)	+= aim-sound/
+obj-$(CONFIG_AIM_V4L2)	+= aim-v4l2/

drivers/staging/most/aim-v4l2/Kconfig

+#
+# MOST V4L2 configuration
+#
+
+config AIM_V4L2
+	tristate "V4L2 AIM"
+	depends on VIDEO_V4L2
+	---help---
+	  Say Y here if you want to commumicate via Video 4 Linux.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called aim_v4l2.
\ No newline at end of file

drivers/staging/most/aim-v4l2/Makefile

+obj-$(CONFIG_AIM_V4L2) += aim_v4l2.o
+
+aim_v4l2-objs := video.o
+
+ccflags-y += -Idrivers/staging/most/mostcore/
+ccflags-y += -Idrivers/media/video

drivers/staging/most/aim-v4l2/video.c

+/*
+ * V4L2 AIM - V4L2 Application Interface Module for MostCore
+ *
+ * Copyright (C) 2015, Microchip Technology Germany II GmbH & Co. KG
+ *
+ * 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.
+ *
+ * This file is licensed under GPLv2.
+ */
+
+#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 "mostcore.h"
+
+
+#define V4L2_AIM_MAX_INPUT  1
+
+
+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 aim_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 struct spinlock list_lock;
+static struct most_aim aim_info;
+
+
+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 aim_vdev_open(struct file *filp)
+{
+	int ret;
+	struct video_device *vdev = video_devdata(filp);
+	struct most_video_dev *mdev = video_drvdata(filp);
+	struct aim_fh *fh;
+
+	pr_info("aim_vdev_open()\n");
+
+	switch (vdev->vfl_type) {
+	case VFL_TYPE_GRABBER:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	fh = kzalloc(sizeof(struct aim_fh), GFP_KERNEL);
+	if (!fh)
+		return -ENOMEM;
+
+	if (!atomic_inc_and_test(&mdev->access_ref)) {
+		pr_err("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);
+	if (ret) {
+		pr_err("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 aim_vdev_close(struct file *filp)
+{
+	struct aim_fh *fh = filp->private_data;
+	struct most_video_dev *mdev = fh->mdev;
+	struct mbo *mbo, *tmp;
+
+	pr_info("aim_vdev_close()\n");
+
+	/*
+	 * 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(&mdev->list_lock);
+	mdev->mute = true;
+	list_for_each_entry_safe(mbo, tmp, &mdev->pending_mbos, list) {
+		list_del(&mbo->list);
+		spin_unlock(&mdev->list_lock);
+		most_put_mbo(mbo);
+		spin_lock(&mdev->list_lock);
+	}
+	spin_unlock(&mdev->list_lock);
+	most_stop_channel(mdev->iface, mdev->ch_idx);
+	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 aim_vdev_read(struct file *filp, char __user *buf,
+			     size_t count, loff_t *pos)
+{
+	struct aim_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)) {
+			pr_err("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(&mdev->list_lock);
+			list_del(&mbo->list);
+			spin_unlock(&mdev->list_lock);
+			most_put_mbo(mbo);
+		}
+	}
+	return ret;
+}
+
+static unsigned int aim_vdev_poll(struct file *filp, poll_table *wait)
+{
+	struct aim_fh *fh = filp->private_data;
+	struct most_video_dev *mdev = fh->mdev;
+	unsigned int 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 |= POLLIN | POLLRDNORM;
+
+	return mask;
+}
+
+static void aim_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 aim_set_format(struct most_video_dev *mdev, unsigned int cmd,
+			  struct v4l2_format *format)
+{
+#if 0
+	u32 const pixfmt = format->fmt.pix.pixelformat;
+	const char *fmt;
+
+	if (pixfmt != V4L2_PIX_FMT_MPEG) {
+		if (cmd == VIDIOC_TRY_FMT)
+			fmt = KERN_ERR "try %c%c%c%c failed\n";
+		else
+			fmt = KERN_ERR "set %c%c%c%c failed\n";
+	} else {
+		if (cmd == VIDIOC_TRY_FMT)
+			fmt = KERN_ERR "try %c%c%c%c\n";
+		else
+			fmt = KERN_ERR "set %c%c%c%c\n";
+	}
+	printk(fmt,
+	       (pixfmt) & 255,
+	       (pixfmt >> 8) & 255,
+	       (pixfmt >> 16) & 255,
+	       (pixfmt >> 24) & 255);
+#endif
+
+	if (format->fmt.pix.pixelformat != V4L2_PIX_FMT_MPEG)
+		return -EINVAL;
+
+	if (cmd == VIDIOC_TRY_FMT)
+		return 0;
+
+	aim_set_format_struct(format);
+
+	return 0;
+}
+
+
+static int vidioc_querycap(struct file *file, void  *priv,
+			   struct v4l2_capability *cap)
+{
+	struct aim_fh *fh = priv;
+	struct most_video_dev *mdev = fh->mdev;
+
+	pr_info("vidioc_querycap()\n");
+
+	strlcpy(cap->driver, "v4l2_most_aim", sizeof(cap->driver));
+	strlcpy(cap->card, "my_card", sizeof(cap->card));
+	snprintf(cap->bus_info, sizeof(cap->bus_info),
+		 "%s", mdev->iface->description);
+
+	cap->capabilities =
+		V4L2_CAP_READWRITE |
+		V4L2_CAP_TUNER |
+		V4L2_CAP_VIDEO_CAPTURE;
+	return 0;
+}
+
+static int vidioc_enum_fmt_vid_cap(struct file *file, void  *priv,
+				   struct v4l2_fmtdesc *f)
+{
+	pr_info("vidioc_enum_fmt_vid_cap() %d\n", f->index);
+
+	if (f->index)
+		return -EINVAL;
+
+	strcpy(f->description, "MPEG");
+	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)
+{
+	pr_info("vidioc_g_fmt_vid_cap()\n");
+
+	aim_set_format_struct(f);
+	return 0;
+}
+
+static int vidioc_try_fmt_vid_cap(struct file *file, void *priv,
+				  struct v4l2_format *f)
+{
+	struct aim_fh *fh  = priv;
+	struct most_video_dev *mdev = fh->mdev;
+
+	return aim_set_format(mdev, VIDIOC_TRY_FMT, f);
+}
+
+static int vidioc_s_fmt_vid_cap(struct file *file, void *priv,
+				struct v4l2_format *f)
+{
+	struct aim_fh *fh  = priv;
+	struct most_video_dev *mdev = fh->mdev;
+
+	return aim_set_format(mdev, VIDIOC_S_FMT, f);
+}
+
+static int vidioc_g_std(struct file *file, void *priv, v4l2_std_id *norm)
+{
+	pr_info("vidioc_g_std()\n");
+
+	*norm = V4L2_STD_UNKNOWN;
+	return 0;
+}
+
+static int vidioc_enum_input(struct file *file, void *priv,
+			     struct v4l2_input *input)
+{
+	struct aim_fh *fh = priv;
+	struct most_video_dev *mdev = fh->mdev;
+
+	if (input->index >= V4L2_AIM_MAX_INPUT)
+		return -EINVAL;
+
+	strcpy(input->name, "MOST Video");
+	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 aim_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 aim_fh *fh = priv;
+	struct most_video_dev *mdev = fh->mdev;
+
+	pr_info("vidioc_s_input(%d)\n", index);
+
+	if (index >= V4L2_AIM_MAX_INPUT)
+		return -EINVAL;
+	mdev->ctrl_input = index;
+	return 0;
+}
+
+static struct v4l2_file_operations aim_fops = {
+	.owner      = THIS_MODULE,
+	.open       = aim_vdev_open,
+	.release    = aim_vdev_close,
+	.read       = aim_vdev_read,
+	.poll       = aim_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 aim_videodev_template = {
+	.fops = &aim_fops,
+	.release = video_device_release,
+	.ioctl_ops = &video_ioctl_ops,
+	.tvnorms = V4L2_STD_UNKNOWN,
+};
+
+/**************************************************************************/
+
+static struct most_video_dev *get_aim_dev(
+	struct most_interface *iface, int channel_idx)
+{
+	struct most_video_dev *mdev, *tmp;
+
+	spin_lock(&list_lock);
+	list_for_each_entry_safe(mdev, tmp, &video_devices, list) {
+		if (mdev->iface == iface && mdev->ch_idx == channel_idx) {
+			spin_unlock(&list_lock);
+			return mdev;
+		}
+	}
+	spin_unlock(&list_lock);
+	return 0;
+}
+
+static int aim_rx_data(struct mbo *mbo)
+{
+	struct most_video_dev *mdev =
+		get_aim_dev(mbo->ifp, mbo->hdm_channel_id);
+
+	if (!mdev)
+		return -EIO;
+
+	spin_lock(&mdev->list_lock);
+	if (unlikely(mdev->mute)) {
+		spin_unlock(&mdev->list_lock);
+		return -EIO;
+	}
+
+	list_add_tail(&mbo->list, &mdev->pending_mbos);
+	spin_unlock(&mdev->list_lock);
+	wake_up_interruptible(&mdev->wait_data);
+	return 0;
+}
+
+static int aim_register_videodev(struct most_video_dev *mdev)
+{
+	int retval = -ENOMEM;
+	int ret;
+
+	pr_info("aim_register_videodev()\n");
+
+	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 = aim_videodev_template;
+	mdev->vdev->v4l2_dev = &mdev->v4l2_dev;
+	mdev->vdev->lock = &mdev->lock;
+	strcpy(mdev->vdev->name, "most v4l2 aim video");
+
+	/* Register the v4l2 device */
+	video_set_drvdata(mdev->vdev, mdev);
+	retval = video_register_device(mdev->vdev, VFL_TYPE_GRABBER, -1);
+	if (retval != 0) {
+		pr_err("video_register_device failed (%d)\n", retval);
+		ret = -ENODEV;
+		goto err_vbi_dev;
+	}
+
+	return 0;
+
+err_vbi_dev:
+	video_device_release(mdev->vdev);
+	return ret;
+}
+
+static void aim_unregister_videodev(struct most_video_dev *mdev)
+{
+	pr_info("aim_unregister_videodev()\n");
+
+	video_unregister_device(mdev->vdev);
+}
+
+
+static void aim_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 aim_probe_channel(struct most_interface *iface, int channel_idx,
+			     struct most_channel_config *ccfg,
+			     struct kobject *parent, char *name)
+{
+	int ret;
+	struct most_video_dev *mdev = get_aim_dev(iface, channel_idx);
+
+	pr_info("aim_probe_channel()\n");
+
+	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_AVP) {
+		pr_err("wrong channel type, expect sync or isoc_avp\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 = aim_v4l2_dev_release;
+
+	/* Create the v4l2_device */
+	strlcpy(mdev->v4l2_dev.name, "most_video_device",
+		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 = aim_register_videodev(mdev);
+	if (ret)
+		goto err_unreg;
+
+	spin_lock(&list_lock);
+	list_add(&mdev->list, &video_devices);
+	spin_unlock(&list_lock);
+	return 0;
+
+err_unreg:
+	v4l2_device_disconnect(&mdev->v4l2_dev);
+	v4l2_device_put(&mdev->v4l2_dev);
+	return ret;
+}
+
+static int aim_disconnect_channel(struct most_interface *iface,
+				  int channel_idx)
+{
+	struct most_video_dev *mdev = get_aim_dev(iface, channel_idx);
+
+	pr_info("aim_disconnect_channel()\n");
+
+	if (!mdev) {
+		pr_err("no such channel is linked\n");
+		return -ENOENT;
+	}
+
+	spin_lock(&list_lock);
+	list_del(&mdev->list);
+	spin_unlock(&list_lock);
+
+	aim_unregister_videodev(mdev);
+	v4l2_device_disconnect(&mdev->v4l2_dev);
+	v4l2_device_put(&mdev->v4l2_dev);
+	return 0;
+}
+
+static int __init aim_init(void)
+{
+	spin_lock_init(&list_lock);
+
+	aim_info.name = "v4l";
+	aim_info.probe_channel = aim_probe_channel;
+	aim_info.disconnect_channel = aim_disconnect_channel;
+	aim_info.rx_completion = aim_rx_data;
+	return most_register_aim(&aim_info);
+}
+
+static void __exit aim_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_aim()
+	 * we simulate this call here.
+	 * This must be fixed in core.
+	 */
+	spin_lock(&list_lock);
+	list_for_each_entry_safe(mdev, tmp, &video_devices, list) {
+		list_del(&mdev->list);
+		spin_unlock(&list_lock);
+
+		aim_unregister_videodev(mdev);
+		v4l2_device_disconnect(&mdev->v4l2_dev);
+		v4l2_device_put(&mdev->v4l2_dev);
+	}
+	spin_unlock(&list_lock);
+
+	most_deregister_aim(&aim_info);
+	BUG_ON(!list_empty(&video_devices));
+}
+
+module_init(aim_init);
+module_exit(aim_exit);
+
+MODULE_DESCRIPTION("V4L2 Application Interface Module for MostCore");
+MODULE_AUTHOR("Andrey Shvetsov <andrey.shvetsov@k2l.de>");
+MODULE_LICENSE("GPL");