aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/firmware/iscsi_ibft_find.c
blob: bfe723266fd89bb84726d88cf15c206c020ee707 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
/*
 *  Copyright 2007-2010 Red Hat, Inc.
 *  by Peter Jones <pjones@redhat.com>
 *  Copyright 2007 IBM, Inc.
 *  by Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
 *  Copyright 2008
 *  by Konrad Rzeszutek <ketuzsezr@darnok.org>
 *
 * This code finds the iSCSI Boot Format Table.
 *
 * 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.
 */

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

#include <asm/mmzone.h>

/*
 * Physical location of iSCSI Boot Format Table.
 */
struct acpi_table_ibft *ibft_addr;
EXPORT_SYMBOL_GPL(ibft_addr);

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

#define IBFT_SIGN_LEN 4
#define IBFT_START 0x80000 /* 512kB */
#define IBFT_END 0x100000 /* 1MB */
#define VGA_MEM 0xA0000 /* VGA buffer */
#define VGA_SIZE 0x20000 /* 128kB */

#ifdef CONFIG_ACPI
static int __init acpi_find_ibft(struct acpi_table_header *header)
{
	ibft_addr = (struct acpi_table_ibft *)header;
	return 0;
}
#endif /* CONFIG_ACPI */

static int __init find_ibft_in_mem(void)
{
	unsigned long pos;
	unsigned int len = 0;
	void *virt;
	int i;

	for (pos = IBFT_START; pos < IBFT_END; pos += 16) {
		/* The table can't be inside the VGA BIOS reserved space,
		 * so skip that area */
		if (pos == VGA_MEM)
			pos += VGA_SIZE;
		virt = isa_bus_to_virt(pos);

		for (i = 0; i < ARRAY_SIZE(ibft_signs); i++) {
			if (memcmp(virt, ibft_signs[i].sign, IBFT_SIGN_LEN) ==
			    0) {
				unsigned long *addr =
				    (unsigned long *)isa_bus_to_virt(pos + 4);
				len = *addr;
				/* if the length of the table extends past 1M,
				 * the table cannot be valid. */
				if (pos + len <= (IBFT_END-1)) {
					ibft_addr = (struct acpi_table_ibft *)virt;
					goto done;
				}
			}
		}
	}
done:
	return len;
}
/*
 * Routine used to find the iSCSI Boot Format Table. The logical
 * kernel address is set in the ibft_addr global variable.
 */
unsigned long __init find_ibft_region(unsigned long *sizep)
{
#ifdef CONFIG_ACPI
	int i;
#endif
	ibft_addr = NULL;

#ifdef CONFIG_ACPI
	for (i = 0; i < ARRAY_SIZE(ibft_signs) && !ibft_addr; i++)
		acpi_table_parse(ibft_signs[i].sign, acpi_find_ibft);
#endif /* CONFIG_ACPI */

	/* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will
	 * only use ACPI for this */

	if (!ibft_addr && !efi_enabled)
		find_ibft_in_mem();

	if (ibft_addr) {
		*sizep = PAGE_ALIGN(ibft_addr->header.length);
		return (u64)isa_virt_to_bus(ibft_addr);
	}

	*sizep = 0;
	return 0;
}