linux/drivers/firmware/iscsi_ibft_find.c
<<
>>
Prefs
   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