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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/dmi.h>
  20 #include <linux/err.h>
  21 #include <linux/gfp.h>
  22 #include <linux/mutex.h>
  23 #include <linux/slab.h>
  24 #include <linux/io.h>
  25 #include "../../firmware/dcdbas.h"
  26 #include "dell-smbios.h"
  27
  28 struct calling_interface_structure {
  29         struct dmi_header header;
  30         u16 cmdIOAddress;
  31         u8 cmdIOCode;
  32         u32 supportedCmds;
  33         struct calling_interface_token tokens[];
  34 } __packed;
  35
  36 static struct calling_interface_buffer *buffer;
  37 static DEFINE_MUTEX(buffer_mutex);
  38
  39 static int da_command_address;
  40 static int da_command_code;
  41 static int da_num_tokens;
  42 static struct calling_interface_token *da_tokens;
  43
  44 int dell_smbios_error(int value)
  45 {
  46         switch (value) {
  47         case 0: /* Completed successfully */
  48                 return 0;
  49         case -1: /* Completed with error */
  50                 return -EIO;
  51         case -2: /* Function not supported */
  52                 return -ENXIO;
  53         default: /* Unknown error */
  54                 return -EINVAL;
  55         }
  56 }
  57 EXPORT_SYMBOL_GPL(dell_smbios_error);
  58
  59 struct calling_interface_buffer *dell_smbios_get_buffer(void)
  60 {
  61         mutex_lock(&buffer_mutex);
  62         dell_smbios_clear_buffer();
  63         return buffer;
  64 }
  65 EXPORT_SYMBOL_GPL(dell_smbios_get_buffer);
  66
  67 void dell_smbios_clear_buffer(void)
  68 {
  69         memset(buffer, 0, sizeof(struct calling_interface_buffer));
  70 }
  71 EXPORT_SYMBOL_GPL(dell_smbios_clear_buffer);
  72
  73 void dell_smbios_release_buffer(void)
  74 {
  75         mutex_unlock(&buffer_mutex);
  76 }
  77 EXPORT_SYMBOL_GPL(dell_smbios_release_buffer);
  78
  79 void dell_smbios_send_request(int class, int select)
  80 {
  81         struct smi_cmd command;
  82
  83         command.magic = SMI_CMD_MAGIC;
  84         command.command_address = da_command_address;
  85         command.command_code = da_command_code;
  86         command.ebx = virt_to_phys(buffer);
  87         command.ecx = 0x42534931;
  88
  89         buffer->cmd_class = class;
  90         buffer->cmd_select = select;
  91
  92         dcdbas_smi_request(&command);
  93 }
  94 EXPORT_SYMBOL_GPL(dell_smbios_send_request);
  95
  96 struct calling_interface_token *dell_smbios_find_token(int tokenid)
  97 {
  98         int i;
  99
 100         for (i = 0; i < da_num_tokens; i++) {
 101                 if (da_tokens[i].tokenID == tokenid)
 102                         return &da_tokens[i];
 103         }
 104
 105         return NULL;
 106 }
 107 EXPORT_SYMBOL_GPL(dell_smbios_find_token);
 108
 109 static BLOCKING_NOTIFIER_HEAD(dell_laptop_chain_head);
 110
 111 int dell_laptop_register_notifier(struct notifier_block *nb)
 112 {
 113         return blocking_notifier_chain_register(&dell_laptop_chain_head, nb);
 114 }
 115 EXPORT_SYMBOL_GPL(dell_laptop_register_notifier);
 116
 117 int dell_laptop_unregister_notifier(struct notifier_block *nb)
 118 {
 119         return blocking_notifier_chain_unregister(&dell_laptop_chain_head, nb);
 120 }
 121 EXPORT_SYMBOL_GPL(dell_laptop_unregister_notifier);
 122
 123 void dell_laptop_call_notifier(unsigned long action, void *data)
 124 {
 125         blocking_notifier_call_chain(&dell_laptop_chain_head, action, data);
 126 }
 127 EXPORT_SYMBOL_GPL(dell_laptop_call_notifier);
 128
 129 static void __init parse_da_table(const struct dmi_header *dm)
 130 {
 131         /* Final token is a terminator, so we don't want to copy it */
 132         int tokens = (dm->length-11)/sizeof(struct calling_interface_token)-1;
 133         struct calling_interface_token *new_da_tokens;
 134         struct calling_interface_structure *table =
 135                 container_of(dm, struct calling_interface_structure, header);
 136
 137         /* 4 bytes of table header, plus 7 bytes of Dell header, plus at least
 138            6 bytes of entry */
 139
 140         if (dm->length < 17)
 141                 return;
 142
 143         da_command_address = table->cmdIOAddress;
 144         da_command_code = table->cmdIOCode;
 145
 146         new_da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) *
 147                                  sizeof(struct calling_interface_token),
 148                                  GFP_KERNEL);
 149
 150         if (!new_da_tokens)
 151                 return;
 152         da_tokens = new_da_tokens;
 153
 154         memcpy(da_tokens+da_num_tokens, table->tokens,
 155                sizeof(struct calling_interface_token) * tokens);
 156
 157         da_num_tokens += tokens;
 158 }
 159
 160 static void __init find_tokens(const struct dmi_header *dm, void *dummy)
 161 {
 162         switch (dm->type) {
 163         case 0xd4: /* Indexed IO */
 164         case 0xd5: /* Protected Area Type 1 */
 165         case 0xd6: /* Protected Area Type 2 */
 166                 break;
 167         case 0xda: /* Calling interface */
 168                 parse_da_table(dm);
 169                 break;
 170         }
 171 }
 172
 173 static int __init dell_smbios_init(void)
 174 {
 175         int ret;
 176
 177         dmi_walk(find_tokens, NULL);
 178
 179         if (!da_tokens)  {
 180                 pr_info("Unable to find dmi tokens\n");
 181                 return -ENODEV;
 182         }
 183
 184         /*
 185          * Allocate buffer below 4GB for SMI data--only 32-bit physical addr
 186          * is passed to SMI handler.
 187          */
 188         buffer = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
 189         if (!buffer) {
 190                 ret = -ENOMEM;
 191                 goto fail_buffer;
 192         }
 193
 194         return 0;
 195
 196 fail_buffer:
 197         kfree(da_tokens);
 198         return ret;
 199 }
 200
 201 static void __exit dell_smbios_exit(void)
 202 {
 203         kfree(da_tokens);
 204         free_page((unsigned long)buffer);
 205 }
 206
 207 subsys_initcall(dell_smbios_init);
 208 module_exit(dell_smbios_exit);
 209
 210 MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
 211 MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@gmail.com>");
 212 MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
 213 MODULE_DESCRIPTION("Common functions for kernel modules using Dell SMBIOS");
 214 MODULE_LICENSE("GPL");