/*
 *  copyright (c) 2006 IBM Corporation
 *  Authored by: Mike D. Day <ncmike@us.ibm.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/err.h>

#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>

#include <xen/xen.h>
#include <xen/xenbus.h>
#include <xen/interface/xen.h>
#include <xen/interface/version.h>

#define HYPERVISOR_ATTR_RO(_name) \
static struct hyp_sysfs_attr  _name##_attr = __ATTR_RO(_name)

#define HYPERVISOR_ATTR_RW(_name) \
static struct hyp_sysfs_attr _name##_attr = \
	__ATTR(_name, 0644, _name##_show, _name##_store)

struct hyp_sysfs_attr {
	struct attribute attr;
	ssize_t (*show)(struct hyp_sysfs_attr *, char *);
	ssize_t (*store)(struct hyp_sysfs_attr *, const char *, size_t);
	void *hyp_attr_data;
};

static ssize_t type_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	return sprintf(buffer, "xen\n");
}

HYPERVISOR_ATTR_RO(type);

static int __init xen_sysfs_type_init(void)
{
	return sysfs_create_file(hypervisor_kobj, &type_attr.attr);
}

static void xen_sysfs_type_destroy(void)
{
	sysfs_remove_file(hypervisor_kobj, &type_attr.attr);
}

/* xen version attributes */
static ssize_t major_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	int version = HYPERVISOR_xen_version(XENVER_version, NULL);
	if (version)
		return sprintf(buffer, "%d\n", version >> 16);
	return -ENODEV;
}

HYPERVISOR_ATTR_RO(major);

static ssize_t minor_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	int version = HYPERVISOR_xen_version(XENVER_version, NULL);
	if (version)
		return sprintf(buffer, "%d\n", version & 0xff);
	return -ENODEV;
}

HYPERVISOR_ATTR_RO(minor);

static ssize_t extra_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	int ret = -ENOMEM;
	char *extra;

	extra = kmalloc(XEN_EXTRAVERSION_LEN, GFP_KERNEL);
	if (extra) {
		ret = HYPERVISOR_xen_version(XENVER_extraversion, extra);
		if (!ret)
			ret = sprintf(buffer, "%s\n", extra);
		kfree(extra);
	}

	return ret;
}

HYPERVISOR_ATTR_RO(extra);

static struct attribute *version_attrs[] = {
	&major_attr.attr,
	&minor_attr.attr,
	&extra_attr.attr,
	NULL
};

static const struct attribute_group version_group = {
	.name = "version",
	.attrs = version_attrs,
};

static int __init xen_sysfs_version_init(void)
{
	return sysfs_create_group(hypervisor_kobj, &version_group);
}

static void xen_sysfs_version_destroy(void)
{
	sysfs_remove_group(hypervisor_kobj, &version_group);
}

/* UUID */

static ssize_t uuid_show_fallback(struct hyp_sysfs_attr *attr, char *buffer)
{
	char *vm, *val;
	int ret;
	extern int xenstored_ready;

	if (!xenstored_ready)
		return -EBUSY;

	vm = xenbus_read(XBT_NIL, "vm", "", NULL);
	if (IS_ERR(vm))
		return PTR_ERR(vm);
	val = xenbus_read(XBT_NIL, vm, "uuid", NULL);
	kfree(vm);
	if (IS_ERR(val))
		return PTR_ERR(val);
	ret = sprintf(buffer, "%s\n", val);
	kfree(val);
	return ret;
}

static ssize_t uuid_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	xen_domain_handle_t uuid;
	int ret;
	ret = HYPERVISOR_xen_version(XENVER_guest_handle, uuid);
	if (ret)
		return uuid_show_fallback(attr, buffer);
	ret = sprintf(buffer, "%pU\n", uuid);
	return ret;
}

HYPERVISOR_ATTR_RO(uuid);

static int __init xen_sysfs_uuid_init(void)
{
	return sysfs_create_file(hypervisor_kobj, &uuid_attr.attr);
}

static void xen_sysfs_uuid_destroy(void)
{
	sysfs_remove_file(hypervisor_kobj, &uuid_attr.attr);
}

/* xen compilation attributes */

static ssize_t compiler_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	int ret = -ENOMEM;
	struct xen_compile_info *info;

	info = kmalloc(sizeof(struct xen_compile_info), GFP_KERNEL);
	if (info) {
		ret = HYPERVISOR_xen_version(XENVER_compile_info, info);
		if (!ret)
			ret = sprintf(buffer, "%s\n", info->compiler);
		kfree(info);
	}

	return ret;
}

HYPERVISOR_ATTR_RO(compiler);

static ssize_t compiled_by_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	int ret = -ENOMEM;
	struct xen_compile_info *info;

	info = kmalloc(sizeof(struct xen_compile_info), GFP_KERNEL);
	if (info) {
		ret = HYPERVISOR_xen_version(XENVER_compile_info, info);
		if (!ret)
			ret = sprintf(buffer, "%s\n", info->compile_by);
		kfree(info);
	}

	return ret;
}

HYPERVISOR_ATTR_RO(compiled_by);

static ssize_t compile_date_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	int ret = -ENOMEM;
	struct xen_compile_info *info;

	info = kmalloc(sizeof(struct xen_compile_info), GFP_KERNEL);
	if (info) {
		ret = HYPERVISOR_xen_version(XENVER_compile_info, info);
		if (!ret)
			ret = sprintf(buffer, "%s\n", info->compile_date);
		kfree(info);
	}

	return ret;
}

HYPERVISOR_ATTR_RO(compile_date);

static struct attribute *xen_compile_attrs[] = {
	&compiler_attr.attr,
	&compiled_by_attr.attr,
	&compile_date_attr.attr,
	NULL
};

static const struct attribute_group xen_compilation_group = {
	.name = "compilation",
	.attrs = xen_compile_attrs,
};

static int __init xen_compilation_init(void)
{
	return sysfs_create_group(hypervisor_kobj, &xen_compilation_group);
}

static void xen_compilation_destroy(void)
{
	sysfs_remove_group(hypervisor_kobj, &xen_compilation_group);
}

/* xen properties info */

static ssize_t capabilities_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	int ret = -ENOMEM;
	char *caps;

	caps = kmalloc(XEN_CAPABILITIES_INFO_LEN, GFP_KERNEL);
	if (caps) {
		ret = HYPERVISOR_xen_version(XENVER_capabilities, caps);
		if (!ret)
			ret = sprintf(buffer, "%s\n", caps);
		kfree(caps);
	}

	return ret;
}

HYPERVISOR_ATTR_RO(capabilities);

static ssize_t changeset_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	int ret = -ENOMEM;
	char *cset;

	cset = kmalloc(XEN_CHANGESET_INFO_LEN, GFP_KERNEL);
	if (cset) {
		ret = HYPERVISOR_xen_version(XENVER_changeset, cset);
		if (!ret)
			ret = sprintf(buffer, "%s\n", cset);
		kfree(cset);
	}

	return ret;
}

HYPERVISOR_ATTR_RO(changeset);

static ssize_t virtual_start_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	int ret = -ENOMEM;
	struct xen_platform_parameters *parms;

	parms = kmalloc(sizeof(struct xen_platform_parameters), GFP_KERNEL);
	if (parms) {
		ret = HYPERVISOR_xen_version(XENVER_platform_parameters,
					     parms);
		if (!ret)
			ret = sprintf(buffer, "%"PRI_xen_ulong"\n",
				      parms->virt_start);
		kfree(parms);
	}

	return ret;
}

HYPERVISOR_ATTR_RO(virtual_start);

static ssize_t pagesize_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	int ret;

	ret = HYPERVISOR_xen_version(XENVER_pagesize, NULL);
	if (ret > 0)
		ret = sprintf(buffer, "%x\n", ret);

	return ret;
}

HYPERVISOR_ATTR_RO(pagesize);

static ssize_t xen_feature_show(int index, char *buffer)
{
	ssize_t ret;
	struct xen_feature_info info;

	info.submap_idx = index;
	ret = HYPERVISOR_xen_version(XENVER_get_features, &info);
	if (!ret)
		ret = sprintf(buffer, "%08x", info.submap);

	return ret;
}

static ssize_t features_show(struct hyp_sysfs_attr *attr, char *buffer)
{
	ssize_t len;
	int i;

	len = 0;
	for (i = XENFEAT_NR_SUBMAPS-1; i >= 0; i--) {
		int ret = xen_feature_show(i, buffer + len);
		if (ret < 0) {
			if (len == 0)
				len = ret;
			break;
		}
		len += ret;
	}
	if (len > 0)
		buffer[len++] = '\n';

	return len;
}

HYPERVISOR_ATTR_RO(features);

static struct attribute *xen_properties_attrs[] = {
	&capabilities_attr.attr,
	&changeset_attr.attr,
	&virtual_start_attr.attr,
	&pagesize_attr.attr,
	&features_attr.attr,
	NULL
};

static const struct attribute_group xen_properties_group = {
	.name = "properties",
	.attrs = xen_properties_attrs,
};

static int __init xen_properties_init(void)
{
	return sysfs_create_group(hypervisor_kobj, &xen_properties_group);
}

static void xen_properties_destroy(void)
{
	sysfs_remove_group(hypervisor_kobj, &xen_properties_group);
}

static int __init hyper_sysfs_init(void)
{
	int ret;

	if (!xen_domain())
		return -ENODEV;

	ret = xen_sysfs_type_init();
	if (ret)
		goto out;
	ret = xen_sysfs_version_init();
	if (ret)
		goto version_out;
	ret = xen_compilation_init();
	if (ret)
		goto comp_out;
	ret = xen_sysfs_uuid_init();
	if (ret)
		goto uuid_out;
	ret = xen_properties_init();
	if (ret)
		goto prop_out;

	goto out;

prop_out:
	xen_sysfs_uuid_destroy();
uuid_out:
	xen_compilation_destroy();
comp_out:
	xen_sysfs_version_destroy();
version_out:
	xen_sysfs_type_destroy();
out:
	return ret;
}

static void __exit hyper_sysfs_exit(void)
{
	xen_properties_destroy();
	xen_compilation_destroy();
	xen_sysfs_uuid_destroy();
	xen_sysfs_version_destroy();
	xen_sysfs_type_destroy();

}
module_init(hyper_sysfs_init);
module_exit(hyper_sysfs_exit);

static ssize_t hyp_sysfs_show(struct kobject *kobj,
			      struct attribute *attr,
			      char *buffer)
{
	struct hyp_sysfs_attr *hyp_attr;
	hyp_attr = container_of(attr, struct hyp_sysfs_attr, attr);
	if (hyp_attr->show)
		return hyp_attr->show(hyp_attr, buffer);
	return 0;
}

static ssize_t hyp_sysfs_store(struct kobject *kobj,
			       struct attribute *attr,
			       const char *buffer,
			       size_t len)
{
	struct hyp_sysfs_attr *hyp_attr;
	hyp_attr = container_of(attr, struct hyp_sysfs_attr, attr);
	if (hyp_attr->store)
		return hyp_attr->store(hyp_attr, buffer, len);
	return 0;
}

static const struct sysfs_ops hyp_sysfs_ops = {
	.show = hyp_sysfs_show,
	.store = hyp_sysfs_store,
};

static struct kobj_type hyp_sysfs_kobj_type = {
	.sysfs_ops = &hyp_sysfs_ops,
};

static int __init hypervisor_subsys_init(void)
{
	if (!xen_domain())
		return -ENODEV;

	hypervisor_kobj->ktype = &hyp_sysfs_kobj_type;
	return 0;
}
device_initcall(hypervisor_subsys_init);