#include <linux/kernel.h>
#include <linux/version.h>
#define DAHDI_PRINK_MACROS_USE_debug
#include <dahdi/kernel.h>
#include <linux/device.h>
#include <linux/slab.h>

#include "dahdi.h"

/* FIXME: Move to kernel.h */
#define module_printk(level, fmt, args...) printk(level "%s: " fmt, THIS_MODULE->name, ## args)

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27)
#define CLASS_DEV_CREATE(class, devt, device, name) \
	device_create(class, device, devt, NULL, "%s", name)
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26)
#define CLASS_DEV_CREATE(class, devt, device, name) \
	device_create(class, device, devt, name)
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,15)
#define CLASS_DEV_CREATE(class, devt, device, name) \
        class_device_create(class, NULL, devt, device, name)
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,13)
#define CLASS_DEV_CREATE(class, devt, device, name) \
        class_device_create(class, devt, device, name)
#else
#define CLASS_DEV_CREATE(class, devt, device, name) \
        class_simple_device_add(class, devt, device, name)
#endif

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26)
#define CLASS_DEV_DESTROY(class, devt) \
	device_destroy(class, devt)
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,13)
#define CLASS_DEV_DESTROY(class, devt) \
	class_device_destroy(class, devt)
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,9)
#define CLASS_DEV_DESTROY(class, devt) \
	class_simple_device_remove(devt)
#else
#define CLASS_DEV_DESTROY(class, devt) \
	class_simple_device_remove(class, devt)
#endif

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,13)
static struct class *dahdi_class = NULL;
#else
static struct class_simple *dahdi_class = NULL;
#define class_create class_simple_create
#define class_destroy class_simple_destroy
#endif

/*
 * Very old hotplug support
 */
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 9)
#define	OLD_HOTPLUG_SUPPORT	/* for older kernels */
#define	OLD_HOTPLUG_SUPPORT_269
#endif

#ifdef	OLD_HOTPLUG_SUPPORT_269
/* Copy from new kernels lib/kobject_uevent.c */
enum kobject_action {
	KOBJ_ADD,
	KOBJ_REMOVE,
	KOBJ_CHANGE,
	KOBJ_MOUNT,
	KOBJ_UMOUNT,
	KOBJ_OFFLINE,
	KOBJ_ONLINE,
};
#endif

/*
 * Hotplug replaced with uevent in 2.6.16
 */
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 16)
#define	OLD_HOTPLUG_SUPPORT	/* for older kernels */
#endif

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 14)
#define	DEVICE_ATTR_READER(name, dev, buf)	\
		ssize_t name(struct device *dev, struct device_attribute *attr,\
				char *buf)
#define	DEVICE_ATTR_WRITER(name, dev, buf, count)	\
		ssize_t name(struct device *dev, struct device_attribute *attr,\
				const char *buf, size_t count)
#define BUS_ATTR_READER(name, dev, buf) \
	ssize_t name(struct device *dev, struct device_attribute *attr, \
		char *buf)
#define BUS_ATTR_WRITER(name, dev, buf, count) \
		ssize_t name(struct device *dev, struct device_attribute *attr,\
			const char *buf, size_t count)
#else
#define	DEVICE_ATTR_READER(name, dev, buf)	\
		ssize_t name(struct device *dev, char *buf)
#define	DEVICE_ATTR_WRITER(name, dev, buf, count)	\
		ssize_t name(struct device *dev, const char *buf, size_t count)
#define BUS_ATTR_READER(name, dev, buf) \
		ssize_t name(struct device *dev, char *buf)
#define BUS_ATTR_WRITER(name, dev, buf, count) \
		ssize_t name(struct device *dev, const char *buf, size_t count)
#endif

#define	DRIVER_ATTR_READER(name, drv, buf)	\
		ssize_t name(struct device_driver *drv, char * buf)


static char *initdir = "/usr/share/dahdi";
module_param(initdir, charp, 0644);

static int span_match(struct device *dev, struct device_driver *driver)
{
	return 1;
}

static inline struct dahdi_span *dev_to_span(struct device *const dev)
{
	return dev_get_drvdata(dev);
}

#ifdef OLD_HOTPLUG_SUPPORT
static int span_hotplug(struct device *dev, char **envp, int envnum,
		char *buff, int bufsize)
{
	struct dahdi_span *span;

	if (!dev)
		return -ENODEV;
	span = dev_to_span(dev);
	envp[0] = buff;
	if (snprintf(buff, bufsize, "SPAN_NAME=%s", span->name) >= bufsize)
		return -ENOMEM;
	envp[1] = NULL;
	return 0;
}
#else

#define	SPAN_VAR_BLOCK	\
	do {		\
		DAHDI_ADD_UEVENT_VAR("DAHDI_INIT_DIR=%s", initdir);	\
		DAHDI_ADD_UEVENT_VAR("SPAN_NUM=%d", span->spanno);	\
		DAHDI_ADD_UEVENT_VAR("SPAN_NAME=%s", span->name);	\
	} while (0)

#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 24)
#define DAHDI_ADD_UEVENT_VAR(fmt, val...)			\
	do {							\
		int err = add_uevent_var(envp, num_envp, &i,	\
				buffer, buffer_size, &len,	\
				fmt, val);			\
		if (err)					\
			return err;				\
	} while (0)

#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
#define dev_name(dev)		((dev)->bus_id)
#define dev_set_name(dev, format, ...) \
	snprintf((dev)->bus_id, BUS_ID_SIZE, format, ## __VA_ARGS__);
#endif

static int span_uevent(struct device *dev, char **envp, int num_envp,
		char *buffer, int buffer_size)
{
	struct dahdi_span	*span;
	int			i = 0;
	int			len = 0;

	if (!dev)
		return -ENODEV;

	span = dev_to_span(dev);
	if (!span)
		return -ENODEV;

	dahdi_dbg(GENERAL, "SYFS dev_name=%s span=%s\n",
			dev_name(dev), span->name);
	SPAN_VAR_BLOCK;
	envp[i] = NULL;
	return 0;
}

#else
#define DAHDI_ADD_UEVENT_VAR(fmt, val...)			\
	do {							\
		int err = add_uevent_var(kenv, fmt, val);	\
		if (err)					\
			return err;				\
	} while (0)

static int span_uevent(struct device *dev, struct kobj_uevent_env *kenv)
{
	struct dahdi_span *span;

	if (!dev)
		return -ENODEV;
	span = dev_to_span(dev);
	if (!span)
		return -ENODEV;
	dahdi_dbg(GENERAL, "SYFS dev_name=%s span=%s\n",
			dev_name(dev), span->name);
	SPAN_VAR_BLOCK;
	return 0;
}

#endif

#endif	/* OLD_HOTPLUG_SUPPORT */

#define span_attr(field, format_string)				\
static BUS_ATTR_READER(field##_show, dev, buf)			\
{								\
	struct dahdi_span *span;				\
								\
	span = dev_to_span(dev);				\
	return sprintf(buf, format_string, span->field);	\
}

span_attr(name, "%s\n");
span_attr(desc, "%s\n");
span_attr(spantype, "%s\n");
span_attr(alarms, "0x%x\n");
span_attr(lbo, "%d\n");
span_attr(syncsrc, "%d\n");

static struct device_attribute span_dev_attrs[] = {
	__ATTR_RO(name),
	__ATTR_RO(desc),
	__ATTR_RO(spantype),
	__ATTR_RO(alarms),
	__ATTR_RO(lbo),
	__ATTR_RO(syncsrc),
	__ATTR_NULL,
};

static struct driver_attribute dahdi_attrs[] = {
	__ATTR_NULL,
};

static struct bus_type spans_bus_type = {
	.name           = "dahdi_spans",
	.match          = span_match,
#ifdef OLD_HOTPLUG_SUPPORT
	.hotplug	= span_hotplug,
#else
	.uevent         = span_uevent,
#endif
	.dev_attrs	= span_dev_attrs,
	.drv_attrs	= dahdi_attrs,
};

static int span_probe(struct device *dev)
{
	struct dahdi_span *span;

	span = dev_to_span(dev);
	return 0;
}

static int span_remove(struct device *dev)
{
	struct dahdi_span *span;

	span = dev_to_span(dev);
	return 0;
}

static struct device_driver dahdi_driver = {
	.name		= "generic_lowlevel",
	.bus		= &spans_bus_type,
	.probe		= span_probe,
	.remove		= span_remove,
#ifndef OLD_HOTPLUG_SUPPORT
	.owner		= THIS_MODULE
#endif
};

static void span_uevent_send(struct dahdi_span *span, enum kobject_action act)
{
	struct kobject	*kobj;

	kobj = &span->span_device->kobj;
	span_dbg(DEVICES, span, "SYFS dev_name=%s action=%d\n",
		dev_name(span->span_device), act);

#if defined(OLD_HOTPLUG_SUPPORT_269)
	{
		/* Copy from new kernels lib/kobject_uevent.c */
		static const char *const str[] = {
			[KOBJ_ADD]	"add",
			[KOBJ_REMOVE]	"remove",
			[KOBJ_CHANGE]	"change",
			[KOBJ_MOUNT]	"mount",
			[KOBJ_UMOUNT]	"umount",
			[KOBJ_OFFLINE]	"offline",
			[KOBJ_ONLINE]	"online"
		};
		kobject_hotplug(str[act], kobj);
	}
#elif defined(OLD_HOTPLUG_SUPPORT)
	kobject_hotplug(kobj, act);
#else
	kobject_uevent(kobj, act);
#endif
}

static void span_release(struct device *dev)
{
	dahdi_dbg(DEVICES, "%s: %s\n", __func__, dev_name(dev));
}

int dahdi_register_chardev(struct dahdi_chardev *dev)
{
	static const char *DAHDI_STRING = "dahdi!";
	char *udevname;

	udevname = kzalloc(strlen(dev->name) + sizeof(DAHDI_STRING) + 1,
			   GFP_KERNEL);
	if (!udevname)
		return -ENOMEM;

	strcpy(udevname, DAHDI_STRING);
	strcat(udevname, dev->name);
	CLASS_DEV_CREATE(dahdi_class, MKDEV(DAHDI_MAJOR, dev->minor), NULL, udevname);
	kfree(udevname);
	return 0;
}
EXPORT_SYMBOL(dahdi_register_chardev);

int dahdi_unregister_chardev(struct dahdi_chardev *dev)
{
	CLASS_DEV_DESTROY(dahdi_class, MKDEV(DAHDI_MAJOR, dev->minor));

	return 0;
}
EXPORT_SYMBOL(dahdi_unregister_chardev);

void span_sysfs_remove(struct dahdi_span *span)
{
	struct device *span_device;
	int x;

	span_dbg(DEVICES, span, "\n");
	span_device = span->span_device;

	if (!span_device)
		return;

	for (x = 0; x < span->channels; x++) {
		struct dahdi_chan *chan = span->chans[x];
		if (!test_bit(DAHDI_FLAGBIT_DEVFILE, &chan->flags))
			continue;

		CLASS_DEV_DESTROY(dahdi_class,
				MKDEV(DAHDI_MAJOR, chan->channo));
		clear_bit(DAHDI_FLAGBIT_DEVFILE, &chan->flags);
	}
	if (!dev_get_drvdata(span_device))
		return;
	span_uevent_send(span, KOBJ_OFFLINE);
	dev_set_drvdata(span_device, NULL);
	span_device->parent = NULL;
	device_unregister(span->span_device);
}

int span_sysfs_create(struct dahdi_span *span)
{
	struct device *span_device;
	int res = 0;
	int x;

	if (span->span_device) {
		WARN_ON(1);
		return -EEXIST;
	}

	span->span_device = kzalloc(sizeof(*span->span_device), GFP_KERNEL);
	if (!span->span_device)
		return -ENOMEM;

	span_device = span->span_device;
	span_dbg(DEVICES, span, "\n");

	span_device->bus = &spans_bus_type;
	span_device->parent = &span->parent->dev;
	dev_set_name(span_device, "span-%03d", span->spanno);
	dev_set_drvdata(span_device, span);
	span_device->release = span_release;
	res = device_register(span_device);
	if (res) {
		span_err(span, "%s: device_register failed: %d\n", __func__,
				res);
		goto cleanup;
	}

	for (x = 0; x < span->channels; x++) {
		struct dahdi_chan *chan = span->chans[x];
		char chan_name[32];
		void *dummy;

		if (chan->channo >= 250)
			continue;
		if (test_bit(DAHDI_FLAGBIT_DEVFILE, &chan->flags))
			continue;

		snprintf(chan_name, sizeof(chan_name), "dahdi!%d",
				chan->channo);
		dummy = (void *)CLASS_DEV_CREATE(dahdi_class,
				MKDEV(DAHDI_MAJOR, chan->channo),
				NULL, chan_name);
		if (IS_ERR(dummy)) {
			res = PTR_ERR(dummy);
			chan_err(chan, "Failed creating sysfs device: %d\n",
					res);
			goto cleanup;
		}

		set_bit(DAHDI_FLAGBIT_DEVFILE, &chan->flags);
	}
	return 0;

cleanup:
	span_sysfs_remove(span);
	return res;
}

#define MAKE_DAHDI_DEV(num, name) \
	CLASS_DEV_CREATE(dahdi_class, MKDEV(DAHDI_MAJOR, num), NULL, name)
#define DEL_DAHDI_DEV(num) \
	CLASS_DEV_DESTROY(dahdi_class, MKDEV(DAHDI_MAJOR, num))

/* Only used to flag that the device exists: */
static struct {
	unsigned int ctl:1;
	unsigned int timer:1;
	unsigned int channel:1;
	unsigned int pseudo:1;
	unsigned int sysfs_driver_registered:1;
	unsigned int sysfs_spans_bus_type:1;
	unsigned int dahdi_device_bus_registered:1;
} dummy_dev;

static inline struct dahdi_device *to_ddev(struct device *dev)
{
	return container_of(dev, struct dahdi_device, dev);
}

static ssize_t
dahdi_device_manufacturer_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	struct dahdi_device *ddev = to_ddev(dev);
	return sprintf(buf, "%s\n", ddev->manufacturer);
}

static ssize_t
dahdi_device_type_show(struct device *dev,
		       struct device_attribute *attr, char *buf)
{
	struct dahdi_device *ddev = to_ddev(dev);
	return sprintf(buf, "%s\n", ddev->devicetype);
}

static ssize_t
dahdi_device_span_count_show(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	struct dahdi_device *ddev = to_ddev(dev);
	unsigned int count = 0;
	struct list_head *pos;

	list_for_each(pos, &ddev->spans)
		++count;

	return sprintf(buf, "%d\n", count);
}

static ssize_t
dahdi_device_location_show(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	struct dahdi_device *ddev = to_ddev(dev);

	return sprintf(buf, "%s\n", ddev->location);
}

static ssize_t
dahdi_device_auto_register(struct device *dev, struct device_attribute *attr,
			   const char *buf, size_t count)
{
	struct dahdi_device *ddev = to_ddev(dev);
	dahdi_register_device_spans(ddev);
	return count;
}

static ssize_t
dahdi_device_register_span(struct device *dev, struct device_attribute *attr,
			   const char *buf, size_t count)
{
	int ret;
	struct dahdi_span *span;
	unsigned int span_offset;
	unsigned int desired_spanno;
	unsigned int desired_basechanno;
	struct dahdi_device *const ddev = to_ddev(dev);

	ret = sscanf(buf, "%u:%u:%u", &span_offset, &desired_spanno,
		     &desired_basechanno);
	if (ret != 3)
		return -EINVAL;

	list_for_each_entry(span, &ddev->spans, device_node) {
		if (span_offset == span->offset) {
			ret = dahdi_register_span(span, desired_spanno,
						  desired_basechanno, 1);
			return (ret) ? ret : count;
		}
	}

	return -EINVAL;
}

static struct device_attribute dahdi_device_attrs[] = {
	__ATTR(manufacturer, S_IRUGO, dahdi_device_manufacturer_show, NULL),
	__ATTR(type, S_IRUGO, dahdi_device_type_show, NULL),
	__ATTR(span_count, S_IRUGO, dahdi_device_span_count_show, NULL),
	__ATTR(location, S_IRUGO, dahdi_device_location_show, NULL),
	__ATTR(auto_register, S_IWUSR, NULL, dahdi_device_auto_register),
	__ATTR(register_span, S_IWUSR, NULL, dahdi_device_register_span),
	__ATTR_NULL,
};

static struct bus_type dahdi_device_bus = {
	.name = "dahdi_devices",
	.dev_attrs = dahdi_device_attrs,
};

void dahdi_sysfs_exit(void)
{
	dahdi_dbg(DEVICES, "SYSFS\n");
	if (dummy_dev.pseudo) {
		dahdi_dbg(DEVICES, "Removing /dev/dahdi/pseudo:\n");
		DEL_DAHDI_DEV(DAHDI_PSEUDO);
		dummy_dev.pseudo = 0;
	}
	if (dummy_dev.channel) {
		dahdi_dbg(DEVICES, "Removing /dev/dahdi/channel:\n");
		DEL_DAHDI_DEV(DAHDI_CHANNEL);
		dummy_dev.channel = 0;
	}
	if (dummy_dev.timer) {
		dahdi_dbg(DEVICES, "Removing /dev/dahdi/timer:\n");
		DEL_DAHDI_DEV(DAHDI_TIMER);
		dummy_dev.timer = 0;
	}
	if (dummy_dev.ctl) {
		dahdi_dbg(DEVICES, "Removing /dev/dahdi/ctl:\n");
		DEL_DAHDI_DEV(DAHDI_CTL);
		dummy_dev.ctl = 0;
	}
	if (dahdi_class) {
		dahdi_dbg(DEVICES, "Destroying DAHDI class:\n");
		class_destroy(dahdi_class);
		dahdi_class = NULL;
	}
	if (dummy_dev.sysfs_driver_registered) {
		dahdi_dbg(DEVICES, "Unregister driver\n");
		driver_unregister(&dahdi_driver);
		dummy_dev.sysfs_driver_registered = 0;
	}
	if (dummy_dev.sysfs_spans_bus_type) {
		dahdi_dbg(DEVICES, "Unregister span bus type\n");
		bus_unregister(&spans_bus_type);
		dummy_dev.sysfs_spans_bus_type = 0;
	}
	unregister_chrdev(DAHDI_MAJOR, "dahdi");

	if (dummy_dev.dahdi_device_bus_registered) {
		bus_unregister(&dahdi_device_bus);
		dummy_dev.dahdi_device_bus_registered = 0;
	}
}

static void dahdi_device_release(struct device *dev)
{
	struct dahdi_device *ddev = container_of(dev, struct dahdi_device, dev);
	kfree(ddev);
}

/**
 * dahdi_sysfs_add_device - Add the dahdi_device into the sysfs hierarchy.
 * @ddev:	The device to add.
 * @parent:	The physical device that is implementing this device.
 *
 * By adding the dahdi_device to the sysfs hierarchy user space can control
 * how spans are numbered.
 *
 */
int dahdi_sysfs_add_device(struct dahdi_device *ddev, struct device *parent)
{
	int ret;
	struct device *const dev = &ddev->dev;

	dev->parent = parent;
	dev->bus = &dahdi_device_bus;
	dev->release = dahdi_device_release;
	dev_set_name(dev, "%s:%s", parent->bus->name, dev_name(parent));
	ret = device_add(dev);
	return ret;
}

void dahdi_sysfs_init_device(struct dahdi_device *ddev)
{
	device_initialize(&ddev->dev);
}

void dahdi_sysfs_unregister_device(struct dahdi_device *ddev)
{
	device_del(&ddev->dev);
}

int __init dahdi_sysfs_init(const struct file_operations *dahdi_fops)
{
	int res = 0;
	void *dev;

	res = bus_register(&dahdi_device_bus);
	if (res)
		return res;

	dummy_dev.dahdi_device_bus_registered = 1;

	res = register_chrdev(DAHDI_MAJOR, "dahdi", dahdi_fops);
	if (res) {
		module_printk(KERN_ERR, "Unable to register DAHDI character device handler on %d\n", DAHDI_MAJOR);
		return res;
	}
	module_printk(KERN_INFO, "Telephony Interface Registered on major %d\n",
			DAHDI_MAJOR);
	module_printk(KERN_INFO, "Version: %s\n", dahdi_version);

	dahdi_class = class_create(THIS_MODULE, "dahdi");
	if (!dahdi_class) {
		res = -EEXIST;
		goto cleanup;
	}

	dahdi_dbg(DEVICES, "Creating /dev/dahdi/timer:\n");
	dev = MAKE_DAHDI_DEV(DAHDI_TIMER, "dahdi!timer");
	if (IS_ERR(dev)) {
		res = PTR_ERR(dev);
		goto cleanup;
	}
	dummy_dev.timer = 1;

	dahdi_dbg(DEVICES, "Creating /dev/dahdi/channel:\n");
	dev = MAKE_DAHDI_DEV(DAHDI_CHANNEL, "dahdi!channel");
	if (IS_ERR(dev)) {
		res = PTR_ERR(dev);
		goto cleanup;
	}
	dummy_dev.channel = 1;

	dahdi_dbg(DEVICES, "Creating /dev/dahdi/pseudo:\n");
	dev = MAKE_DAHDI_DEV(DAHDI_PSEUDO, "dahdi!pseudo");
	if (IS_ERR(dev)) {
		res = PTR_ERR(dev);
		goto cleanup;
	}
	dummy_dev.pseudo = 1;

	dahdi_dbg(DEVICES, "Creating /dev/dahdi/ctl:\n");
	dev = MAKE_DAHDI_DEV(DAHDI_CTL, "dahdi!ctl");
	if (IS_ERR(dev)) {
		res = PTR_ERR(dev);
		goto cleanup;
	}
	dummy_dev.ctl = 1;
	res = bus_register(&spans_bus_type);
	if (res != 0) {
		dahdi_err("%s: bus_register(%s) failed. Error number %d",
			__func__, spans_bus_type.name, res);
		goto cleanup;
	}
	dummy_dev.sysfs_spans_bus_type = 1;
	res = driver_register(&dahdi_driver);
	if (res < 0) {
		dahdi_err("%s: driver_register(%s) failed. Error number %d",
			__func__, dahdi_driver.name, res);
		goto cleanup;
	}
	dummy_dev.sysfs_driver_registered = 1;

	return 0;

cleanup:
	dahdi_sysfs_exit();
	return res;
}