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 */ 42 struct acpi_table_ibft *ibft_addr; 43 EXPORT_SYMBOL_GPL(ibft_addr); 44 45 static const struct { 46 char *sign; 47 } ibft_signs[] = { 48 { "iBFT" }, 49 { "BIFT" }, /* Broadcom iSCSI Offload */ 50 }; 51 52 #define IBFT_SIGN_LEN 4 53 #define IBFT_START 0x80000 /* 512kB */ 54 #define IBFT_END 0x100000 /* 1MB */ 55 #define VGA_MEM 0xA0000 /* VGA buffer */ 56 #define VGA_SIZE 0x20000 /* 128kB */ 57 58 static int __init find_ibft_in_mem(void) 59 { 60 unsigned long pos; 61 unsigned int len = 0; 62 void *virt; 63 int i; 64 65 for (pos = IBFT_START; pos < IBFT_END; pos += 16) { 66 /* The table can't be inside the VGA BIOS reserved space, 67 * so skip that area */ 68 if (pos == VGA_MEM) 69 pos += VGA_SIZE; 70 virt = isa_bus_to_virt(pos); 71 72 for (i = 0; i < ARRAY_SIZE(ibft_signs); i++) { 73 if (memcmp(virt, ibft_signs[i].sign, IBFT_SIGN_LEN) == 74 0) { 75 unsigned long *addr = 76 (unsigned long *)isa_bus_to_virt(pos + 4); 77 len = *addr; 78 /* if the length of the table extends past 1M, 79 * the table cannot be valid. */ 80 if (pos + len <= (IBFT_END-1)) { 81 ibft_addr = (struct acpi_table_ibft *)virt; 82 pr_info("iBFT found at 0x%lx.\n", pos); 83 goto done; 84 } 85 } 86 } 87 } 88 done: 89 return len; 90 } 91 /* 92 * Routine used to find the iSCSI Boot Format Table. The logical 93 * kernel address is set in the ibft_addr global variable. 94 */ 95 unsigned long __init find_ibft_region(unsigned long *sizep) 96 { 97 ibft_addr = NULL; 98 99 /* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will 100 * only use ACPI for this */ 101 102 if (!efi_enabled(EFI_BOOT)) 103 find_ibft_in_mem(); 104 105 if (ibft_addr) { 106 *sizep = PAGE_ALIGN(ibft_addr->header.length); 107 return (u64)isa_virt_to_bus(ibft_addr); 108 } 109 110 *sizep = 0; 111 return 0; 112 } 113