1/* 2 * Copyright 2007-2010 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/efi.h> 26#include <linux/err.h> 27#include <linux/init.h> 28#include <linux/limits.h> 29#include <linux/module.h> 30#include <linux/pci.h> 31#include <linux/stat.h> 32#include <linux/string.h> 33#include <linux/types.h> 34#include <linux/acpi.h> 35#include <linux/iscsi_ibft.h> 36 37#include <asm/mmzone.h> 38 39/* 40 * Physical location of iSCSI Boot Format Table. 41 */ 42struct acpi_table_ibft *ibft_addr; 43EXPORT_SYMBOL_GPL(ibft_addr); 44 45#define IBFT_SIGN "iBFT" 46#define IBFT_SIGN_LEN 4 47#define IBFT_START 0x80000 /* 512kB */ 48#define IBFT_END 0x100000 /* 1MB */ 49#define VGA_MEM 0xA0000 /* VGA buffer */ 50#define VGA_SIZE 0x20000 /* 128kB */ 51 52#ifdef CONFIG_ACPI 53static int __init acpi_find_ibft(struct acpi_table_header *header) 54{ 55 ibft_addr = (struct acpi_table_ibft *)header; 56 return 0; 57} 58#endif /* CONFIG_ACPI */ 59 60static int __init find_ibft_in_mem(void) 61{ 62 unsigned long pos; 63 unsigned int len = 0; 64 void *virt; 65 66 for (pos = IBFT_START; pos < IBFT_END; pos += 16) { 67 /* The table can't be inside the VGA BIOS reserved space, 68 * so skip that area */ 69 if (pos == VGA_MEM) 70 pos += VGA_SIZE; 71 virt = isa_bus_to_virt(pos); 72 if (memcmp(virt, IBFT_SIGN, IBFT_SIGN_LEN) == 0) { 73 unsigned long *addr = 74 (unsigned long *)isa_bus_to_virt(pos + 4); 75 len = *addr; 76 /* if the length of the table extends past 1M, 77 * the table cannot be valid. */ 78 if (pos + len <= (IBFT_END-1)) { 79 ibft_addr = (struct acpi_table_ibft *)virt; 80 break; 81 } 82 } 83 } 84 return len; 85} 86/* 87 * Routine used to find the iSCSI Boot Format Table. The logical 88 * kernel address is set in the ibft_addr global variable. 89 */ 90unsigned long __init find_ibft_region(unsigned long *sizep) 91{ 92 93 ibft_addr = NULL; 94 95#ifdef CONFIG_ACPI 96 /* 97 * One spec says "IBFT", the other says "iBFT". We have to check 98 * for both. 99 */ 100 if (!ibft_addr) 101 acpi_table_parse(ACPI_SIG_IBFT, acpi_find_ibft); 102 if (!ibft_addr) 103 acpi_table_parse(IBFT_SIGN, acpi_find_ibft); 104#endif /* CONFIG_ACPI */ 105 106 /* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will 107 * only use ACPI for this */ 108 109 if (!ibft_addr && !efi_enabled) 110 find_ibft_in_mem(); 111 112 if (ibft_addr) { 113 *sizep = PAGE_ALIGN(ibft_addr->header.length); 114 return (u64)isa_virt_to_bus(ibft_addr); 115 } 116 117 *sizep = 0; 118 return 0; 119} 120