LXR linux/drivers/firmware/iscsi_ibft

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  Copyright 2007-2010 Red Hat, Inc.
   4 *  by Peter Jones <pjones@redhat.com>
   5 *  Copyright 2007 IBM, Inc.
   6 *  by Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
   7 *  Copyright 2008
   8 *  by Konrad Rzeszutek <ketuzsezr@darnok.org>
   9 *
  10 * This code finds the iSCSI Boot Format Table.
  11 */
  12
  13#include <linux/memblock.h>
  14#include <linux/blkdev.h>
  15#include <linux/ctype.h>
  16#include <linux/device.h>
  17#include <linux/efi.h>
  18#include <linux/err.h>
  19#include <linux/init.h>
  20#include <linux/limits.h>
  21#include <linux/module.h>
  22#include <linux/pci.h>
  23#include <linux/stat.h>
  24#include <linux/string.h>
  25#include <linux/types.h>
  26#include <linux/acpi.h>
  27#include <linux/iscsi_ibft.h>
  28
  29#include <asm/mmzone.h>
  30
  31/*
  32 * Physical location of iSCSI Boot Format Table.
  33 */
  34struct acpi_table_ibft *ibft_addr;
  35EXPORT_SYMBOL_GPL(ibft_addr);
  36
  37static const struct {
  38        char *sign;
  39} ibft_signs[] = {
  40        { "iBFT" },
  41        { "BIFT" },     /* Broadcom iSCSI Offload */
  42};
  43
  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
  50static int __init find_ibft_in_mem(void)
  51{
  52        unsigned long pos;
  53        unsigned int len = 0;
  54        void *virt;
  55        int i;
  56
  57        for (pos = IBFT_START; pos < IBFT_END; pos += 16) {
  58                /* The table can't be inside the VGA BIOS reserved space,
  59                 * so skip that area */
  60                if (pos == VGA_MEM)
  61                        pos += VGA_SIZE;
  62                virt = isa_bus_to_virt(pos);
  63
  64                for (i = 0; i < ARRAY_SIZE(ibft_signs); i++) {
  65                        if (memcmp(virt, ibft_signs[i].sign, IBFT_SIGN_LEN) ==
  66                            0) {
  67                                unsigned long *addr =
  68                                    (unsigned long *)isa_bus_to_virt(pos + 4);
  69                                len = *addr;
  70                                /* if the length of the table extends past 1M,
  71                                 * the table cannot be valid. */
  72                                if (pos + len <= (IBFT_END-1)) {
  73                                        ibft_addr = (struct acpi_table_ibft *)virt;
  74                                        pr_info("iBFT found at 0x%lx.\n", pos);
  75                                        goto done;
  76                                }
  77                        }
  78                }
  79        }
  80done:
  81        return len;
  82}
  83/*
  84 * Routine used to find the iSCSI Boot Format Table. The logical
  85 * kernel address is set in the ibft_addr global variable.
  86 */
  87unsigned long __init find_ibft_region(unsigned long *sizep)
  88{
  89        ibft_addr = NULL;
  90
  91        /* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will
  92         * only use ACPI for this */
  93
  94        if (!efi_enabled(EFI_BOOT))
  95                find_ibft_in_mem();
  96
  97        if (ibft_addr) {
  98                *sizep = PAGE_ALIGN(ibft_addr->header.length);
  99                return (u64)virt_to_phys(ibft_addr);
 100        }
 101
 102        *sizep = 0;
 103        return 0;
 104}
 105