blob: d6470ef36e4a937b7c840b6fff4b7788ce40076b [file] [log] [blame]
Konrad Rzeszutek138fe4e2008-04-09 19:50:41 -07001/*
2 * Copyright 2007 Red Hat, Inc.
3 * by Peter Jones <pjones@redhat.com>
4 * Copyright 2007 IBM, Inc.
5 * by Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
6 * Copyright 2008
7 * by Konrad Rzeszutek <ketuzsezr@darnok.org>
8 *
9 * This code finds the iSCSI Boot Format Table.
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License v2.0 as published by
13 * the Free Software Foundation
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 */
20
21#include <linux/bootmem.h>
22#include <linux/blkdev.h>
23#include <linux/ctype.h>
24#include <linux/device.h>
25#include <linux/err.h>
26#include <linux/init.h>
27#include <linux/limits.h>
28#include <linux/module.h>
29#include <linux/pci.h>
Konrad Rzeszutek138fe4e2008-04-09 19:50:41 -070030#include <linux/stat.h>
31#include <linux/string.h>
32#include <linux/types.h>
33
34#include <asm/mmzone.h>
35
36/*
37 * Physical location of iSCSI Boot Format Table.
38 */
39struct ibft_table_header *ibft_addr;
40EXPORT_SYMBOL_GPL(ibft_addr);
41
42#define IBFT_SIGN "iBFT"
43#define IBFT_SIGN_LEN 4
44#define IBFT_START 0x80000 /* 512kB */
45#define IBFT_END 0x100000 /* 1MB */
46#define VGA_MEM 0xA0000 /* VGA buffer */
47#define VGA_SIZE 0x20000 /* 128kB */
48
49
50/*
51 * Routine used to find the iSCSI Boot Format Table. The logical
52 * kernel address is set in the ibft_addr global variable.
53 */
Yinghai Lu042be382010-04-01 14:32:43 -070054unsigned long __init find_ibft_region(unsigned long *sizep)
Konrad Rzeszutek138fe4e2008-04-09 19:50:41 -070055{
56 unsigned long pos;
57 unsigned int len = 0;
58 void *virt;
59
Harvey Harrisona01e0352008-04-28 16:50:04 -070060 ibft_addr = NULL;
Konrad Rzeszutek138fe4e2008-04-09 19:50:41 -070061
62 for (pos = IBFT_START; pos < IBFT_END; pos += 16) {
63 /* The table can't be inside the VGA BIOS reserved space,
64 * so skip that area */
65 if (pos == VGA_MEM)
66 pos += VGA_SIZE;
Jan Beuliched3c6612009-10-02 16:12:39 +010067 virt = isa_bus_to_virt(pos);
Konrad Rzeszutek138fe4e2008-04-09 19:50:41 -070068 if (memcmp(virt, IBFT_SIGN, IBFT_SIGN_LEN) == 0) {
69 unsigned long *addr =
Jan Beuliched3c6612009-10-02 16:12:39 +010070 (unsigned long *)isa_bus_to_virt(pos + 4);
Konrad Rzeszutek138fe4e2008-04-09 19:50:41 -070071 len = *addr;
72 /* if the length of the table extends past 1M,
73 * the table cannot be valid. */
74 if (pos + len <= (IBFT_END-1)) {
75 ibft_addr = (struct ibft_table_header *)virt;
76 break;
77 }
78 }
79 }
Yinghai Lu042be382010-04-01 14:32:43 -070080 if (ibft_addr) {
81 *sizep = PAGE_ALIGN(len);
82 return pos;
83 }
84
85 *sizep = 0;
86 return 0;
Konrad Rzeszutek138fe4e2008-04-09 19:50:41 -070087}