/*
 *  Copyright 2007-2010 Red Hat, Inc.
 *  by Peter Jones <pjones@redhat.com>
 *  Copyright 2008 IBM, Inc.
 *  by Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *  Copyright 2008
 *  by Konrad Rzeszutek <ketuzsezr@darnok.org>
 *
 * This code exposes the iSCSI Boot Format Table to userland via sysfs.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License v2.0 as published by
 * the Free Software Foundation
 *
 * 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.
 *
 * Changelog:
 *
 *  06 Jan 2010 - Peter Jones <pjones@redhat.com>
 *    New changelog entries are in the git log from now on.  Not here.
 *
 *  14 Mar 2008 - Konrad Rzeszutek <ketuzsezr@darnok.org>
 *    Updated comments and copyrights. (v0.4.9)
 *
 *  11 Feb 2008 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *    Converted to using ibft_addr. (v0.4.8)
 *
 *   8 Feb 2008 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *    Combined two functions in one: reserve_ibft_region. (v0.4.7)
 *
 *  30 Jan 2008 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *   Added logic to handle IPv6 addresses. (v0.4.6)
 *
 *  25 Jan 2008 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *   Added logic to handle badly not-to-spec iBFT. (v0.4.5)
 *
 *   4 Jan 2008 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *   Added __init to function declarations. (v0.4.4)
 *
 *  21 Dec 2007 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *   Updated kobject registration, combined unregister functions in one
 *   and code and style cleanup. (v0.4.3)
 *
 *   5 Dec 2007 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *   Added end-markers to enums and re-organized kobject registration. (v0.4.2)
 *
 *   4 Dec 2007 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *   Created 'device' sysfs link to the NIC and style cleanup. (v0.4.1)
 *
 *  28 Nov 2007 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *   Added sysfs-ibft documentation, moved 'find_ibft' function to
 *   in its own file and added text attributes for every struct field.  (v0.4)
 *
 *  21 Nov 2007 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *   Added text attributes emulating OpenFirmware /proc/device-tree naming.
 *   Removed binary /sysfs interface (v0.3)
 *
 *  29 Aug 2007 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *   Added functionality in setup.c to reserve iBFT region. (v0.2)
 *
 *  27 Aug 2007 - Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *   First version exposing iBFT data via a binary /sysfs. (v0.1)
 *
 */


#include <linux/blkdev.h>
#include <linux/capability.h>
#include <linux/ctype.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/iscsi_ibft.h>
#include <linux/limits.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/acpi.h>
#include <linux/iscsi_boot_sysfs.h>

#define IBFT_ISCSI_VERSION "0.5.0"
#define IBFT_ISCSI_DATE "2010-Feb-25"

MODULE_AUTHOR("Peter Jones <pjones@redhat.com> and "
	      "Konrad Rzeszutek <ketuzsezr@darnok.org>");
MODULE_DESCRIPTION("sysfs interface to BIOS iBFT information");
MODULE_LICENSE("GPL");
MODULE_VERSION(IBFT_ISCSI_VERSION);

#ifndef CONFIG_ISCSI_IBFT_FIND
struct acpi_table_ibft *ibft_addr;
#endif

struct ibft_hdr {
	u8 id;
	u8 version;
	u16 length;
	u8 index;
	u8 flags;
} __attribute__((__packed__));

struct ibft_control {
	struct ibft_hdr hdr;
	u16 extensions;
	u16 initiator_off;
	u16 nic0_off;
	u16 tgt0_off;
	u16 nic1_off;
	u16 tgt1_off;
} __attribute__((__packed__));

struct ibft_initiator {
	struct ibft_hdr hdr;
	char isns_server[16];
	char slp_server[16];
	char pri_radius_server[16];
	char sec_radius_server[16];
	u16 initiator_name_len;
	u16 initiator_name_off;
} __attribute__((__packed__));

struct ibft_nic {
	struct ibft_hdr hdr;
	char ip_addr[16];
	u8 subnet_mask_prefix;
	u8 origin;
	char gateway[16];
	char primary_dns[16];
	char secondary_dns[16];
	char dhcp[16];
	u16 vlan;
	char mac[6];
	u16 pci_bdf;
	u16 hostname_len;
	u16 hostname_off;
} __attribute__((__packed__));

struct ibft_tgt {
	struct ibft_hdr hdr;
	char ip_addr[16];
	u16 port;
	char lun[8];
	u8 chap_type;
	u8 nic_assoc;
	u16 tgt_name_len;
	u16 tgt_name_off;
	u16 chap_name_len;
	u16 chap_name_off;
	u16 chap_secret_len;
	u16 chap_secret_off;
	u16 rev_chap_name_len;
	u16 rev_chap_name_off;
	u16 rev_chap_secret_len;
	u16 rev_chap_secret_off;
} __attribute__((__packed__));

/*
 * The kobject different types and its names.
 *
*/
enum ibft_id {
	id_reserved = 0, /* We don't support. */
	id_control = 1, /* Should show up only once and is not exported. */
	id_initiator = 2,
	id_nic = 3,
	id_target = 4,
	id_extensions = 5, /* We don't support. */
	id_end_marker,
};

/*
 * The kobject and attribute structures.
 */

struct ibft_kobject {
	struct acpi_table_ibft *header;
	union {
		struct ibft_initiator *initiator;
		struct ibft_nic *nic;
		struct ibft_tgt *tgt;
		struct ibft_hdr *hdr;
	};
};

static struct iscsi_boot_kset *boot_kset;

/* fully null address */
static const char nulls[16];

/* IPv4-mapped IPv6 ::ffff:0.0.0.0 */
static const char mapped_nulls[16] = { 0x00, 0x00, 0x00, 0x00,
                                       0x00, 0x00, 0x00, 0x00,
                                       0x00, 0x00, 0xff, 0xff,
                                       0x00, 0x00, 0x00, 0x00 };

static int address_not_null(u8 *ip)
{
	return (memcmp(ip, nulls, 16) && memcmp(ip, mapped_nulls, 16));
}

/*
 * Helper functions to parse data properly.
 */
static ssize_t sprintf_ipaddr(char *buf, u8 *ip)
{
	char *str = buf;

	if (ip[0] == 0 && ip[1] == 0 && ip[2] == 0 && ip[3] == 0 &&
	    ip[4] == 0 && ip[5] == 0 && ip[6] == 0 && ip[7] == 0 &&
	    ip[8] == 0 && ip[9] == 0 && ip[10] == 0xff && ip[11] == 0xff) {
		/*
		 * IPV4
		 */
		str += sprintf(buf, "%pI4", ip + 12);
	} else {
		/*
		 * IPv6
		 */
		str += sprintf(str, "%pI6", ip);
	}
	str += sprintf(str, "\n");
	return str - buf;
}

static ssize_t sprintf_string(char *str, int len, char *buf)
{
	return sprintf(str, "%.*s\n", len, buf);
}

/*
 * Helper function to verify the IBFT header.
 */
static int ibft_verify_hdr(char *t, struct ibft_hdr *hdr, int id, int length)
{
	if (hdr->id != id) {
		printk(KERN_ERR "iBFT error: We expected the %s " \
				"field header.id to have %d but " \
				"found %d instead!\n", t, id, hdr->id);
		return -ENODEV;
	}
	if (hdr->length != length) {
		printk(KERN_ERR "iBFT error: We expected the %s " \
				"field header.length to have %d but " \
				"found %d instead!\n", t, length, hdr->length);
		return -ENODEV;
	}

	return 0;
}

/*
 *  Routines for parsing the iBFT data to be human readable.
 */
static ssize_t ibft_attr_show_initiator(void *data, int type, char *buf)
{
	struct ibft_kobject *entry = data;
	struct ibft_initiator *initiator = entry->initiator;
	void *ibft_loc = entry->header;
	char *str = buf;

	if (!initiator)
		return 0;

	switch (type) {
	case ISCSI_BOOT_INI_INDEX:
		str += sprintf(str, "%d\n", initiator->hdr.index);
		break;
	case ISCSI_BOOT_INI_FLAGS:
		str += sprintf(str, "%d\n", initiator->hdr.flags);
		break;
	case ISCSI_BOOT_INI_ISNS_SERVER:
		str += sprintf_ipaddr(str, initiator->isns_server);
		break;
	case ISCSI_BOOT_INI_SLP_SERVER:
		str += sprintf_ipaddr(str, initiator->slp_server);
		break;
	case ISCSI_BOOT_INI_PRI_RADIUS_SERVER:
		str += sprintf_ipaddr(str, initiator->pri_radius_server);
		break;
	case ISCSI_BOOT_INI_SEC_RADIUS_SERVER:
		str += sprintf_ipaddr(str, initiator->sec_radius_server);
		break;
	case ISCSI_BOOT_INI_INITIATOR_NAME:
		str += sprintf_string(str, initiator->initiator_name_len,
				      (char *)ibft_loc +
				      initiator->initiator_name_off);
		break;
	default:
		break;
	}

	return str - buf;
}

static ssize_t ibft_attr_show_nic(void *data, int type, char *buf)
{
	struct ibft_kobject *entry = data;
	struct ibft_nic *nic = entry->nic;
	void *ibft_loc = entry->header;
	char *str = buf;
	__be32 val;

	if (!nic)
		return 0;

	switch (type) {
	case ISCSI_BOOT_ETH_INDEX:
		str += sprintf(str, "%d\n", nic->hdr.index);
		break;
	case ISCSI_BOOT_ETH_FLAGS:
		str += sprintf(str, "%d\n", nic->hdr.flags);
		break;
	case ISCSI_BOOT_ETH_IP_ADDR:
		str += sprintf_ipaddr(str, nic->ip_addr);
		break;
	case ISCSI_BOOT_ETH_SUBNET_MASK:
		val = cpu_to_be32(~((1 << (32-nic->subnet_mask_prefix))-1));
		str += sprintf(str, "%pI4", &val);
		break;
	case ISCSI_BOOT_ETH_ORIGIN:
		str += sprintf(str, "%d\n", nic->origin);
		break;
	case ISCSI_BOOT_ETH_GATEWAY:
		str += sprintf_ipaddr(str, nic->gateway);
		break;
	case ISCSI_BOOT_ETH_PRIMARY_DNS:
		str += sprintf_ipaddr(str, nic->primary_dns);
		break;
	case ISCSI_BOOT_ETH_SECONDARY_DNS:
		str += sprintf_ipaddr(str, nic->secondary_dns);
		break;
	case ISCSI_BOOT_ETH_DHCP:
		str += sprintf_ipaddr(str, nic->dhcp);
		break;
	case ISCSI_BOOT_ETH_VLAN:
		str += sprintf(str, "%d\n", nic->vlan);
		break;
	case ISCSI_BOOT_ETH_MAC:
		str += sprintf(str, "%pM\n", nic->mac);
		break;
	case ISCSI_BOOT_ETH_HOSTNAME:
		str += sprintf_string(str, nic->hostname_len,
				      (char *)ibft_loc + nic->hostname_off);
		break;
	default:
		break;
	}

	return str - buf;
};

static ssize_t ibft_attr_show_target(void *data, int type, char *buf)
{
	struct ibft_kobject *entry = data;
	struct ibft_tgt *tgt = entry->tgt;
	void *ibft_loc = entry->header;
	char *str = buf;
	int i;

	if (!tgt)
		return 0;

	switch (type) {
	case ISCSI_BOOT_TGT_INDEX:
		str += sprintf(str, "%d\n", tgt->hdr.index);
		break;
	case ISCSI_BOOT_TGT_FLAGS:
		str += sprintf(str, "%d\n", tgt->hdr.flags);
		break;
	case ISCSI_BOOT_TGT_IP_ADDR:
		str += sprintf_ipaddr(str, tgt->ip_addr);
		break;
	case ISCSI_BOOT_TGT_PORT:
		str += sprintf(str, "%d\n", tgt->port);
		break;
	case ISCSI_BOOT_TGT_LUN:
		for (i = 0; i < 8; i++)
			str += sprintf(str, "%x", (u8)tgt->lun[i]);
		str += sprintf(str, "\n");
		break;
	case ISCSI_BOOT_TGT_NIC_ASSOC:
		str += sprintf(str, "%d\n", tgt->nic_assoc);
		break;
	case ISCSI_BOOT_TGT_CHAP_TYPE:
		str += sprintf(str, "%d\n", tgt->chap_type);
		break;
	case ISCSI_BOOT_TGT_NAME:
		str += sprintf_string(str, tgt->tgt_name_len,
				      (char *)ibft_loc + tgt->tgt_name_off);
		break;
	case ISCSI_BOOT_TGT_CHAP_NAME:
		str += sprintf_string(str, tgt->chap_name_len,
				      (char *)ibft_loc + tgt->chap_name_off);
		break;
	case ISCSI_BOOT_TGT_CHAP_SECRET:
		str += sprintf_string(str, tgt->chap_secret_len,
				      (char *)ibft_loc + tgt->chap_secret_off);
		break;
	case ISCSI_BOOT_TGT_REV_CHAP_NAME:
		str += sprintf_string(str, tgt->rev_chap_name_len,
				      (char *)ibft_loc +
				      tgt->rev_chap_name_off);
		break;
	case ISCSI_BOOT_TGT_REV_CHAP_SECRET:
		str += sprintf_string(str, tgt->rev_chap_secret_len,
				      (char *)ibft_loc +
				      tgt->rev_chap_secret_off);
		break;
	default:
		break;
	}

	return str - buf;
}

static int __init ibft_check_device(void)
{
	int len;
	u8 *pos;
	u8 csum = 0;

	len = ibft_addr->header.length;

	/* Sanity checking of iBFT. */
	if (ibft_addr->header.revision != 1) {
		printk(KERN_ERR "iBFT module supports only revision 1, " \
				"while this is %d.\n",
				ibft_addr->header.revision);
		return -ENOENT;
	}
	for (pos = (u8 *)ibft_addr; pos < (u8 *)ibft_addr + len; pos++)
		csum += *pos;

	if (csum) {
		printk(KERN_ERR "iBFT has incorrect checksum (0x%x)!\n", csum);
		return -ENOENT;
	}

	return 0;
}

/*
 * Helper routiners to check to determine if the entry is valid
 * in the proper iBFT structure.
 */
static umode_t ibft_check_nic_for(void *data, int type)
{
	struct ibft_kobject *entry = data;
	struct ibft_nic *nic = entry->nic;
	umode_t rc = 0;

	switch (type) {
	case ISCSI_BOOT_ETH_INDEX:
	case ISCSI_BOOT_ETH_FLAGS:
		rc = S_IRUGO;
		break;
	case ISCSI_BOOT_ETH_IP_ADDR:
		if (address_not_null(nic->ip_addr))
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_ETH_SUBNET_MASK:
		if (nic->subnet_mask_prefix)
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_ETH_ORIGIN:
		rc = S_IRUGO;
		break;
	case ISCSI_BOOT_ETH_GATEWAY:
		if (address_not_null(nic->gateway))
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_ETH_PRIMARY_DNS:
		if (address_not_null(nic->primary_dns))
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_ETH_SECONDARY_DNS:
		if (address_not_null(nic->secondary_dns))
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_ETH_DHCP:
		if (address_not_null(nic->dhcp))
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_ETH_VLAN:
	case ISCSI_BOOT_ETH_MAC:
		rc = S_IRUGO;
		break;
	case ISCSI_BOOT_ETH_HOSTNAME:
		if (nic->hostname_off)
			rc = S_IRUGO;
		break;
	default:
		break;
	}

	return rc;
}

static umode_t __init ibft_check_tgt_for(void *data, int type)
{
	struct ibft_kobject *entry = data;
	struct ibft_tgt *tgt = entry->tgt;
	umode_t rc = 0;

	switch (type) {
	case ISCSI_BOOT_TGT_INDEX:
	case ISCSI_BOOT_TGT_FLAGS:
	case ISCSI_BOOT_TGT_IP_ADDR:
	case ISCSI_BOOT_TGT_PORT:
	case ISCSI_BOOT_TGT_LUN:
	case ISCSI_BOOT_TGT_NIC_ASSOC:
	case ISCSI_BOOT_TGT_CHAP_TYPE:
		rc = S_IRUGO;
		break;
	case ISCSI_BOOT_TGT_NAME:
		if (tgt->tgt_name_len)
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_TGT_CHAP_NAME:
	case ISCSI_BOOT_TGT_CHAP_SECRET:
		if (tgt->chap_name_len)
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_TGT_REV_CHAP_NAME:
	case ISCSI_BOOT_TGT_REV_CHAP_SECRET:
		if (tgt->rev_chap_name_len)
			rc = S_IRUGO;
		break;
	default:
		break;
	}

	return rc;
}

static umode_t __init ibft_check_initiator_for(void *data, int type)
{
	struct ibft_kobject *entry = data;
	struct ibft_initiator *init = entry->initiator;
	umode_t rc = 0;

	switch (type) {
	case ISCSI_BOOT_INI_INDEX:
	case ISCSI_BOOT_INI_FLAGS:
		rc = S_IRUGO;
		break;
	case ISCSI_BOOT_INI_ISNS_SERVER:
		if (address_not_null(init->isns_server))
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_INI_SLP_SERVER:
		if (address_not_null(init->slp_server))
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_INI_PRI_RADIUS_SERVER:
		if (address_not_null(init->pri_radius_server))
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_INI_SEC_RADIUS_SERVER:
		if (address_not_null(init->sec_radius_server))
			rc = S_IRUGO;
		break;
	case ISCSI_BOOT_INI_INITIATOR_NAME:
		if (init->initiator_name_len)
			rc = S_IRUGO;
		break;
	default:
		break;
	}

	return rc;
}

static void ibft_kobj_release(void *data)
{
	kfree(data);
}

/*
 * Helper function for ibft_register_kobjects.
 */
static int __init ibft_create_kobject(struct acpi_table_ibft *header,
				      struct ibft_hdr *hdr)
{
	struct iscsi_boot_kobj *boot_kobj = NULL;
	struct ibft_kobject *ibft_kobj = NULL;
	struct ibft_nic *nic = (struct ibft_nic *)hdr;
	struct pci_dev *pci_dev;
	int rc = 0;

	ibft_kobj = kzalloc(sizeof(*ibft_kobj), GFP_KERNEL);
	if (!ibft_kobj)
		return -ENOMEM;

	ibft_kobj->header = header;
	ibft_kobj->hdr = hdr;

	switch (hdr->id) {
	case id_initiator:
		rc = ibft_verify_hdr("initiator", hdr, id_initiator,
				     sizeof(*ibft_kobj->initiator));
		if (rc)
			break;

		boot_kobj = iscsi_boot_create_initiator(boot_kset, hdr->index,
						ibft_kobj,
						ibft_attr_show_initiator,
						ibft_check_initiator_for,
						ibft_kobj_release);
		if (!boot_kobj) {
			rc = -ENOMEM;
			goto free_ibft_obj;
		}
		break;
	case id_nic:
		rc = ibft_verify_hdr("ethernet", hdr, id_nic,
				     sizeof(*ibft_kobj->nic));
		if (rc)
			break;

		boot_kobj = iscsi_boot_create_ethernet(boot_kset, hdr->index,
						       ibft_kobj,
						       ibft_attr_show_nic,
						       ibft_check_nic_for,
						       ibft_kobj_release);
		if (!boot_kobj) {
			rc = -ENOMEM;
			goto free_ibft_obj;
		}
		break;
	case id_target:
		rc = ibft_verify_hdr("target", hdr, id_target,
				     sizeof(*ibft_kobj->tgt));
		if (rc)
			break;

		boot_kobj = iscsi_boot_create_target(boot_kset, hdr->index,
						     ibft_kobj,
						     ibft_attr_show_target,
						     ibft_check_tgt_for,
						     ibft_kobj_release);
		if (!boot_kobj) {
			rc = -ENOMEM;
			goto free_ibft_obj;
		}
		break;
	case id_reserved:
	case id_control:
	case id_extensions:
		/* Fields which we don't support. Ignore them */
		rc = 1;
		break;
	default:
		printk(KERN_ERR "iBFT has unknown structure type (%d). " \
				"Report this bug to %.6s!\n", hdr->id,
				header->header.oem_id);
		rc = 1;
		break;
	}

	if (rc) {
		/* Skip adding this kobject, but exit with non-fatal error. */
		rc = 0;
		goto free_ibft_obj;
	}

	if (hdr->id == id_nic) {
		/*
		* We don't search for the device in other domains than
		* zero. This is because on x86 platforms the BIOS
		* executes only devices which are in domain 0. Furthermore, the
		* iBFT spec doesn't have a domain id field :-(
		*/
		pci_dev = pci_get_bus_and_slot((nic->pci_bdf & 0xff00) >> 8,
					       (nic->pci_bdf & 0xff));
		if (pci_dev) {
			rc = sysfs_create_link(&boot_kobj->kobj,
					       &pci_dev->dev.kobj, "device");
			pci_dev_put(pci_dev);
		}
	}
	return 0;

free_ibft_obj:
	kfree(ibft_kobj);
	return rc;
}

/*
 * Scan the IBFT table structure for the NIC and Target fields. When
 * found add them on the passed-in list. We do not support the other
 * fields at this point, so they are skipped.
 */
static int __init ibft_register_kobjects(struct acpi_table_ibft *header)
{
	struct ibft_control *control = NULL;
	void *ptr, *end;
	int rc = 0;
	u16 offset;
	u16 eot_offset;

	control = (void *)header + sizeof(*header);
	end = (void *)control + control->hdr.length;
	eot_offset = (void *)header + header->header.length - (void *)control;
	rc = ibft_verify_hdr("control", (struct ibft_hdr *)control, id_control,
			     sizeof(*control));

	/* iBFT table safety checking */
	rc |= ((control->hdr.index) ? -ENODEV : 0);
	if (rc) {
		printk(KERN_ERR "iBFT error: Control header is invalid!\n");
		return rc;
	}
	for (ptr = &control->initiator_off; ptr < end; ptr += sizeof(u16)) {
		offset = *(u16 *)ptr;
		if (offset && offset < header->header.length &&
						offset < eot_offset) {
			rc = ibft_create_kobject(header,
						 (void *)header + offset);
			if (rc)
				break;
		}
	}

	return rc;
}

static void ibft_unregister(void)
{
	struct iscsi_boot_kobj *boot_kobj, *tmp_kobj;
	struct ibft_kobject *ibft_kobj;

	list_for_each_entry_safe(boot_kobj, tmp_kobj,
				 &boot_kset->kobj_list, list) {
		ibft_kobj = boot_kobj->data;
		if (ibft_kobj->hdr->id == id_nic)
			sysfs_remove_link(&boot_kobj->kobj, "device");
	};
}

static void ibft_cleanup(void)
{
	if (boot_kset) {
		ibft_unregister();
		iscsi_boot_destroy_kset(boot_kset);
	}
}

static void __exit ibft_exit(void)
{
	ibft_cleanup();
}

#ifdef CONFIG_ACPI
static const struct {
	char *sign;
} ibft_signs[] = {
	/*
	 * One spec says "IBFT", the other says "iBFT". We have to check
	 * for both.
	 */
	{ ACPI_SIG_IBFT },
	{ "iBFT" },
	{ "BIFT" },	/* Broadcom iSCSI Offload */
};

static void __init acpi_find_ibft_region(void)
{
	int i;
	struct acpi_table_header *table = NULL;

	if (acpi_disabled)
		return;

	for (i = 0; i < ARRAY_SIZE(ibft_signs) && !ibft_addr; i++) {
		acpi_get_table(ibft_signs[i].sign, 0, &table);
		ibft_addr = (struct acpi_table_ibft *)table;
	}
}
#else
static void __init acpi_find_ibft_region(void)
{
}
#endif

/*
 * ibft_init() - creates sysfs tree entries for the iBFT data.
 */
static int __init ibft_init(void)
{
	int rc = 0;

	/*
	   As on UEFI systems the setup_arch()/find_ibft_region()
	   is called before ACPI tables are parsed and it only does
	   legacy finding.
	*/
	if (!ibft_addr)
		acpi_find_ibft_region();

	if (ibft_addr) {
		pr_info("iBFT detected.\n");

		rc = ibft_check_device();
		if (rc)
			return rc;

		boot_kset = iscsi_boot_create_kset("ibft");
		if (!boot_kset)
			return -ENOMEM;

		/* Scan the IBFT for data and register the kobjects. */
		rc = ibft_register_kobjects(ibft_addr);
		if (rc)
			goto out_free;
	} else
		printk(KERN_INFO "No iBFT detected.\n");

	return 0;

out_free:
	ibft_cleanup();
	return rc;
}

module_init(ibft_init);
module_exit(ibft_exit);