LXR linux/drivers/firmware/iscsi_ibft

   1/*
   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>
  30#include <linux/slab.h>
  31#include <linux/stat.h>
  32#include <linux/string.h>
  33#include <linux/types.h>
  34
  35#include <asm/mmzone.h>
  36
  37/*
  38 * Physical location of iSCSI Boot Format Table.
  39 */
  40struct ibft_table_header *ibft_addr;
  41EXPORT_SYMBOL_GPL(ibft_addr);
  42
  43#define IBFT_SIGN "iBFT"
  44#define IBFT_SIGN_LEN 4
  45#define IBFT_START 0x80000 /* 512kB */
  46#define IBFT_END 0x100000 /* 1MB */
  47#define VGA_MEM 0xA0000 /* VGA buffer */
  48#define VGA_SIZE 0x20000 /* 128kB */
  49
  50
  51/*
  52 * Routine used to find the iSCSI Boot Format Table. The logical
  53 * kernel address is set in the ibft_addr global variable.
  54 */
  55void __init reserve_ibft_region(void)
  56{
  57        unsigned long pos;
  58        unsigned int len = 0;
  59        void *virt;
  60
  61        ibft_addr = NULL;
  62
  63        for (pos = IBFT_START; pos < IBFT_END; pos += 16) {
  64                /* The table can't be inside the VGA BIOS reserved space,
  65                 * so skip that area */
  66                if (pos == VGA_MEM)
  67                        pos += VGA_SIZE;
  68                virt = phys_to_virt(pos);
  69                if (memcmp(virt, IBFT_SIGN, IBFT_SIGN_LEN) == 0) {
  70                        unsigned long *addr =
  71                            (unsigned long *)phys_to_virt(pos + 4);
  72                        len = *addr;
  73                        /* if the length of the table extends past 1M,
  74                         * the table cannot be valid. */
  75                        if (pos + len <= (IBFT_END-1)) {
  76                                ibft_addr = (struct ibft_table_header *)virt;
  77                                break;
  78                        }
  79                }
  80        }
  81        if (ibft_addr)
  82                reserve_bootmem(pos, PAGE_ALIGN(len), BOOTMEM_DEFAULT);
  83}
  84