V4L/DVB (8427): videodev: split off the ioctl handling into v4l2-ioctl.c

videodev.c became top-heavy so all the ioctl processing has been split off
into v4l2-ioctl.c. This means videodev.c is back to its original purpose:
creating and registering v4l devices.

Since videodev.c and v4l2-ioctl.c should still remain one module (as least
for now) I also had to rename videodev.c to v4l2-dev.c to prevent a
circular dependency when building a videodev.ko module. This is not a bad
thing, since the source and header now have the same name. And the v4l2-
prefix is useful to see which sources are generic v4l2 support code.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 424 insertions, 0 deletions

diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c
new file mode 100644
index 000000000000..2dd82b16bc35
--- /dev/null
+++ b/drivers/media/video/v4l2-dev.c
@@ -0,0 +1,424 @@
+/*
+ * Video capture interface for Linux version 2
+ *
+ *	A generic video device interface for the LINUX operating system
+ *	using a set of device structures/vectors for low level operations.
+ *
+ *	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.
+ *
+ * Authors:	Alan Cox, <alan@redhat.com> (version 1)
+ *              Mauro Carvalho Chehab <mchehab@infradead.org> (version 2)
+ *
+ * Fixes:	20000516  Claudio Matsuoka <claudio@conectiva.com>
+ *		- Added procfs support
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kmod.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+#include <media/v4l2-common.h>
+
+#define VIDEO_NUM_DEVICES	256
+#define VIDEO_NAME              "video4linux"
+
+/*
+ *	sysfs stuff
+ */
+
+static ssize_t show_index(struct device *cd,
+			 struct device_attribute *attr, char *buf)
+{
+	struct video_device *vfd = container_of(cd, struct video_device,
+						class_dev);
+	return sprintf(buf, "%i\n", vfd->index);
+}
+
+static ssize_t show_name(struct device *cd,
+			 struct device_attribute *attr, char *buf)
+{
+	struct video_device *vfd = container_of(cd, struct video_device,
+						class_dev);
+	return sprintf(buf, "%.*s\n", (int)sizeof(vfd->name), vfd->name);
+}
+
+static struct device_attribute video_device_attrs[] = {
+	__ATTR(name, S_IRUGO, show_name, NULL),
+	__ATTR(index, S_IRUGO, show_index, NULL),
+	__ATTR_NULL
+};
+
+struct video_device *video_device_alloc(void)
+{
+	struct video_device *vfd;
+
+	vfd = kzalloc(sizeof(*vfd), GFP_KERNEL);
+	return vfd;
+}
+EXPORT_SYMBOL(video_device_alloc);
+
+void video_device_release(struct video_device *vfd)
+{
+	kfree(vfd);
+}
+EXPORT_SYMBOL(video_device_release);
+
+static void video_release(struct device *cd)
+{
+	struct video_device *vfd = container_of(cd, struct video_device,
+								class_dev);
+
+#if 1
+	/* needed until all drivers are fixed */
+	if (!vfd->release)
+		return;
+#endif
+	vfd->release(vfd);
+}
+
+static struct class video_class = {
+	.name = VIDEO_NAME,
+	.dev_attrs = video_device_attrs,
+	.dev_release = video_release,
+};
+
+/*
+ *	Active devices
+ */
+
+static struct video_device *video_device[VIDEO_NUM_DEVICES];
+static DEFINE_MUTEX(videodev_lock);
+
+struct video_device *video_devdata(struct file *file)
+{
+	return video_device[iminor(file->f_path.dentry->d_inode)];
+}
+EXPORT_SYMBOL(video_devdata);
+
+/*
+ *	Open a video device - FIXME: Obsoleted
+ */
+static int video_open(struct inode *inode, struct file *file)
+{
+	unsigned int minor = iminor(inode);
+	int err = 0;
+	struct video_device *vfl;
+	const struct file_operations *old_fops;
+
+	if (minor >= VIDEO_NUM_DEVICES)
+		return -ENODEV;
+	lock_kernel();
+	mutex_lock(&videodev_lock);
+	vfl = video_device[minor];
+	if (vfl == NULL) {
+		mutex_unlock(&videodev_lock);
+		request_module("char-major-%d-%d", VIDEO_MAJOR, minor);
+		mutex_lock(&videodev_lock);
+		vfl = video_device[minor];
+		if (vfl == NULL) {
+			mutex_unlock(&videodev_lock);
+			unlock_kernel();
+			return -ENODEV;
+		}
+	}
+	old_fops = file->f_op;
+	file->f_op = fops_get(vfl->fops);
+	if (file->f_op->open)
+		err = file->f_op->open(inode, file);
+	if (err) {
+		fops_put(file->f_op);
+		file->f_op = fops_get(old_fops);
+	}
+	fops_put(old_fops);
+	mutex_unlock(&videodev_lock);
+	unlock_kernel();
+	return err;
+}
+
+/*
+ * open/release helper functions -- handle exclusive opens
+ * Should be removed soon
+ */
+int video_exclusive_open(struct inode *inode, struct file *file)
+{
+	struct video_device *vfl = video_devdata(file);
+	int retval = 0;
+
+	mutex_lock(&vfl->lock);
+	if (vfl->users)
+		retval = -EBUSY;
+	else
+		vfl->users++;
+	mutex_unlock(&vfl->lock);
+	return retval;
+}
+EXPORT_SYMBOL(video_exclusive_open);
+
+int video_exclusive_release(struct inode *inode, struct file *file)
+{
+	struct video_device *vfl = video_devdata(file);
+
+	vfl->users--;
+	return 0;
+}
+EXPORT_SYMBOL(video_exclusive_release);
+
+/**
+ * get_index - assign stream number based on parent device
+ * @vdev: video_device to assign index number to, vdev->dev should be assigned
+ * @num: -1 if auto assign, requested number otherwise
+ *
+ *
+ * returns -ENFILE if num is already in use, a free index number if
+ * successful.
+ */
+static int get_index(struct video_device *vdev, int num)
+{
+	u32 used = 0;
+	const int max_index = sizeof(used) * 8 - 1;
+	int i;
+
+	/* Currently a single v4l driver instance cannot create more than
+	   32 devices.
+	   Increase to u64 or an array of u32 if more are needed. */
+	if (num > max_index) {
+		printk(KERN_ERR "videodev: %s num is too large\n", __func__);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < VIDEO_NUM_DEVICES; i++) {
+		if (video_device[i] != NULL &&
+		    video_device[i] != vdev &&
+		    video_device[i]->dev == vdev->dev) {
+			used |= 1 << video_device[i]->index;
+		}
+	}
+
+	if (num >= 0) {
+		if (used & (1 << num))
+			return -ENFILE;
+		return num;
+	}
+
+	i = ffz(used);
+	return i > max_index ? -ENFILE : i;
+}
+
+static const struct file_operations video_fops;
+
+int video_register_device(struct video_device *vfd, int type, int nr)
+{
+	return video_register_device_index(vfd, type, nr, -1);
+}
+EXPORT_SYMBOL(video_register_device);
+
+/**
+ *	video_register_device - register video4linux devices
+ *	@vfd:  video device structure we want to register
+ *	@type: type of device to register
+ *	@nr:   which device number (0 == /dev/video0, 1 == /dev/video1, ...
+ *             -1 == first free)
+ *
+ *	The registration code assigns minor numbers based on the type
+ *	requested. -ENFILE is returned in all the device slots for this
+ *	category are full. If not then the minor field is set and the
+ *	driver initialize function is called (if non %NULL).
+ *
+ *	Zero is returned on success.
+ *
+ *	Valid types are
+ *
+ *	%VFL_TYPE_GRABBER - A frame grabber
+ *
+ *	%VFL_TYPE_VTX - A teletext device
+ *
+ *	%VFL_TYPE_VBI - Vertical blank data (undecoded)
+ *
+ *	%VFL_TYPE_RADIO - A radio card
+ */
+
+int video_register_device_index(struct video_device *vfd, int type, int nr,
+					int index)
+{
+	int i = 0;
+	int base;
+	int end;
+	int ret;
+	char *name_base;
+
+	switch (type) {
+	case VFL_TYPE_GRABBER:
+		base = MINOR_VFL_TYPE_GRABBER_MIN;
+		end = MINOR_VFL_TYPE_GRABBER_MAX+1;
+		name_base = "video";
+		break;
+	case VFL_TYPE_VTX:
+		base = MINOR_VFL_TYPE_VTX_MIN;
+		end = MINOR_VFL_TYPE_VTX_MAX+1;
+		name_base = "vtx";
+		break;
+	case VFL_TYPE_VBI:
+		base = MINOR_VFL_TYPE_VBI_MIN;
+		end = MINOR_VFL_TYPE_VBI_MAX+1;
+		name_base = "vbi";
+		break;
+	case VFL_TYPE_RADIO:
+		base = MINOR_VFL_TYPE_RADIO_MIN;
+		end = MINOR_VFL_TYPE_RADIO_MAX+1;
+		name_base = "radio";
+		break;
+	default:
+		printk(KERN_ERR "%s called with unknown type: %d\n",
+		       __func__, type);
+		return -1;
+	}
+
+	/* pick a minor number */
+	mutex_lock(&videodev_lock);
+	if (nr >= 0  &&  nr < end-base) {
+		/* use the one the driver asked for */
+		i = base + nr;
+		if (NULL != video_device[i]) {
+			mutex_unlock(&videodev_lock);
+			return -ENFILE;
+		}
+	} else {
+		/* use first free */
+		for (i = base; i < end; i++)
+			if (NULL == video_device[i])
+				break;
+		if (i == end) {
+			mutex_unlock(&videodev_lock);
+			return -ENFILE;
+		}
+	}
+	video_device[i] = vfd;
+	vfd->minor = i;
+
+	ret = get_index(vfd, index);
+	vfd->index = ret;
+
+	mutex_unlock(&videodev_lock);
+
+	if (ret < 0) {
+		printk(KERN_ERR "%s: get_index failed\n", __func__);
+		goto fail_minor;
+	}
+
+	mutex_init(&vfd->lock);
+
+	/* sysfs class */
+	memset(&vfd->class_dev, 0x00, sizeof(vfd->class_dev));
+	vfd->class_dev.class = &video_class;
+	vfd->class_dev.devt = MKDEV(VIDEO_MAJOR, vfd->minor);
+	if (vfd->dev)
+		vfd->class_dev.parent = vfd->dev;
+	sprintf(vfd->class_dev.bus_id, "%s%d", name_base, i - base);
+	ret = device_register(&vfd->class_dev);
+	if (ret < 0) {
+		printk(KERN_ERR "%s: device_register failed\n", __func__);
+		goto fail_minor;
+	}
+
+#if 1
+	/* needed until all drivers are fixed */
+	if (!vfd->release)
+		printk(KERN_WARNING "videodev: \"%s\" has no release callback. "
+		       "Please fix your driver for proper sysfs support, see "
+		       "http://lwn.net/Articles/36850/\n", vfd->name);
+#endif
+	return 0;
+
+fail_minor:
+	mutex_lock(&videodev_lock);
+	video_device[vfd->minor] = NULL;
+	vfd->minor = -1;
+	mutex_unlock(&videodev_lock);
+	return ret;
+}
+EXPORT_SYMBOL(video_register_device_index);
+
+/**
+ *	video_unregister_device - unregister a video4linux device
+ *	@vfd: the device to unregister
+ *
+ *	This unregisters the passed device and deassigns the minor
+ *	number. Future open calls will be met with errors.
+ */
+
+void video_unregister_device(struct video_device *vfd)
+{
+	mutex_lock(&videodev_lock);
+	if (video_device[vfd->minor] != vfd)
+		panic("videodev: bad unregister");
+
+	video_device[vfd->minor] = NULL;
+	device_unregister(&vfd->class_dev);
+	mutex_unlock(&videodev_lock);
+}
+EXPORT_SYMBOL(video_unregister_device);
+
+/*
+ * Video fs operations
+ */
+static const struct file_operations video_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.open		= video_open,
+};
+
+/*
+ *	Initialise video for linux
+ */
+
+static int __init videodev_init(void)
+{
+	int ret;
+
+	printk(KERN_INFO "Linux video capture interface: v2.00\n");
+	if (register_chrdev(VIDEO_MAJOR, VIDEO_NAME, &video_fops)) {
+		printk(KERN_WARNING "video_dev: unable to get major %d\n", VIDEO_MAJOR);
+		return -EIO;
+	}
+
+	ret = class_register(&video_class);
+	if (ret < 0) {
+		unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);
+		printk(KERN_WARNING "video_dev: class_register failed\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static void __exit videodev_exit(void)
+{
+	class_unregister(&video_class);
+	unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);
+}
+
+module_init(videodev_init)
+module_exit(videodev_exit)
+
+MODULE_AUTHOR("Alan Cox, Mauro Carvalho Chehab <mchehab@infradead.org>");
+MODULE_DESCRIPTION("Device registrar for Video4Linux drivers v2");
+MODULE_LICENSE("GPL");
+
+
+/*
+ * Local variables:
+ * c-basic-offset: 8
+ * End:
+ */