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:
+ */