LXR linux/drivers/platform/x86/dell-smbios.c

   1/*
   2 *  Common functions for kernel modules using Dell SMBIOS
   3 *
   4 *  Copyright (c) Red Hat <mjg@redhat.com>
   5 *  Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>
   6 *  Copyright (c) 2014 Pali Rohár <pali.rohar@gmail.com>
   7 *
   8 *  Based on documentation in the libsmbios package:
   9 *  Copyright (C) 2005-2014 Dell Inc.
  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 version 2 as
  13 *  published by the Free Software Foundation.
  14 */
  15
  16#include <linux/kernel.h>
  17#include <linux/module.h>
  18#include <linux/dmi.h>
  19#include <linux/err.h>
  20#include <linux/gfp.h>
  21#include <linux/mutex.h>
  22#include <linux/slab.h>
  23#include <linux/io.h>
  24#include "../../firmware/dcdbas.h"
  25#include "dell-smbios.h"
  26
  27struct calling_interface_structure {
  28        struct dmi_header header;
  29        u16 cmdIOAddress;
  30        u8 cmdIOCode;
  31        u32 supportedCmds;
  32        struct calling_interface_token tokens[];
  33} __packed;
  34
  35static struct calling_interface_buffer *buffer;
  36static DEFINE_MUTEX(buffer_mutex);
  37
  38static int da_command_address;
  39static int da_command_code;
  40static int da_num_tokens;
  41static struct calling_interface_token *da_tokens;
  42
  43int dell_smbios_error(int value)
  44{
  45        switch (value) {
  46        case 0: /* Completed successfully */
  47                return 0;
  48        case -1: /* Completed with error */
  49                return -EIO;
  50        case -2: /* Function not supported */
  51                return -ENXIO;
  52        default: /* Unknown error */
  53                return -EINVAL;
  54        }
  55}
  56EXPORT_SYMBOL_GPL(dell_smbios_error);
  57
  58struct calling_interface_buffer *dell_smbios_get_buffer(void)
  59{
  60        mutex_lock(&buffer_mutex);
  61        dell_smbios_clear_buffer();
  62        return buffer;
  63}
  64EXPORT_SYMBOL_GPL(dell_smbios_get_buffer);
  65
  66void dell_smbios_clear_buffer(void)
  67{
  68        memset(buffer, 0, sizeof(struct calling_interface_buffer));
  69}
  70EXPORT_SYMBOL_GPL(dell_smbios_clear_buffer);
  71
  72void dell_smbios_release_buffer(void)
  73{
  74        mutex_unlock(&buffer_mutex);
  75}
  76EXPORT_SYMBOL_GPL(dell_smbios_release_buffer);
  77
  78void dell_smbios_send_request(int class, int select)
  79{
  80        struct smi_cmd command;
  81
  82        command.magic = SMI_CMD_MAGIC;
  83        command.command_address = da_command_address;
  84        command.command_code = da_command_code;
  85        command.ebx = virt_to_phys(buffer);
  86        command.ecx = 0x42534931;
  87
  88        buffer->class = class;
  89        buffer->select = select;
  90
  91        dcdbas_smi_request(&command);
  92}
  93EXPORT_SYMBOL_GPL(dell_smbios_send_request);
  94
  95struct calling_interface_token *dell_smbios_find_token(int tokenid)
  96{
  97        int i;
  98
  99        for (i = 0; i < da_num_tokens; i++) {
 100                if (da_tokens[i].tokenID == tokenid)
 101                        return &da_tokens[i];
 102        }
 103
 104        return NULL;
 105}
 106EXPORT_SYMBOL_GPL(dell_smbios_find_token);
 107
 108static void __init parse_da_table(const struct dmi_header *dm)
 109{
 110        /* Final token is a terminator, so we don't want to copy it */
 111        int tokens = (dm->length-11)/sizeof(struct calling_interface_token)-1;
 112        struct calling_interface_token *new_da_tokens;
 113        struct calling_interface_structure *table =
 114                container_of(dm, struct calling_interface_structure, header);
 115
 116        /* 4 bytes of table header, plus 7 bytes of Dell header, plus at least
 117           6 bytes of entry */
 118
 119        if (dm->length < 17)
 120                return;
 121
 122        da_command_address = table->cmdIOAddress;
 123        da_command_code = table->cmdIOCode;
 124
 125        new_da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) *
 126                                 sizeof(struct calling_interface_token),
 127                                 GFP_KERNEL);
 128
 129        if (!new_da_tokens)
 130                return;
 131        da_tokens = new_da_tokens;
 132
 133        memcpy(da_tokens+da_num_tokens, table->tokens,
 134               sizeof(struct calling_interface_token) * tokens);
 135
 136        da_num_tokens += tokens;
 137}
 138
 139static void __init find_tokens(const struct dmi_header *dm, void *dummy)
 140{
 141        switch (dm->type) {
 142        case 0xd4: /* Indexed IO */
 143        case 0xd5: /* Protected Area Type 1 */
 144        case 0xd6: /* Protected Area Type 2 */
 145                break;
 146        case 0xda: /* Calling interface */
 147                parse_da_table(dm);
 148                break;
 149        }
 150}
 151
 152static int __init dell_smbios_init(void)
 153{
 154        int ret;
 155
 156        dmi_walk(find_tokens, NULL);
 157
 158        if (!da_tokens)  {
 159                pr_info("Unable to find dmi tokens\n");
 160                return -ENODEV;
 161        }
 162
 163        /*
 164         * Allocate buffer below 4GB for SMI data--only 32-bit physical addr
 165         * is passed to SMI handler.
 166         */
 167        buffer = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
 168        if (!buffer) {
 169                ret = -ENOMEM;
 170                goto fail_buffer;
 171        }
 172
 173        return 0;
 174
 175fail_buffer:
 176        kfree(da_tokens);
 177        return ret;
 178}
 179
 180static void __exit dell_smbios_exit(void)
 181{
 182        kfree(da_tokens);
 183        free_page((unsigned long)buffer);
 184}
 185
 186subsys_initcall(dell_smbios_init);
 187module_exit(dell_smbios_exit);
 188
 189MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
 190MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@gmail.com>");
 191MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
 192MODULE_DESCRIPTION("Common functions for kernel modules using Dell SMBIOS");
 193MODULE_LICENSE("GPL");
 194