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RIOT/cpu/x86/x86_reboot.c 2.87 KB
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  /*
   * Copyright (C) 2016 Kaspar Schleiser <kaspar@schleiser.de>
   *               2014  René Kijewski  <rene.kijewski@fu-berlin.de>
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   */
  
  /**
   * @ingroup     x86
   * @{
   *
   * @file
   * @brief       Configurable reboot handler for x86.
   *
   * @author      René Kijewski <rene.kijewski@fu-berlin.de>
   * @author      Kaspar Schleiser <kaspar@schleiser.de>
   *
   * @}
   */
  
  #include "x86_interrupts.h"
  #include "x86_ports.h"
  #include "x86_reboot.h"
  
  #define KBC_DATA    (0x60)
  #define KBC_STATUS  (0x64)
  #define KBC_COMMAND (0x64)
  
  #define KBC_OUTPUT_FULL (1u << 0)
  #define KBC_INPUT_FULL  (1u << 1)
  
  #define KBC_RESET ((uint8_t) ~(1u << 0))
  
  static const struct idtr_t EMPTY_IDT = {
      .limit = 0,
      .base = NULL,
  };
  
  void x86_load_empty_idt(void)
  {
      __asm__ volatile ("lidt %0" :: "m"(EMPTY_IDT));
  }
  
  static bool fail_violently;
  
  void NORETURN x86_kbc_reboot(void)
  {
      /* First load an empty IDT. Any interrupt will cause a tripple fault. */
      x86_load_empty_idt();
  
      while (1) {
          if (fail_violently) {
              __asm__ volatile ("int3"); /* Cause a tripple fault. Won't return. */
          }
          fail_violently = true;
  
          for (unsigned i = 0; i < 0x100; ++i) {
              for (unsigned j = 0; j < 0x10000; ++j) {
                  uint8_t c = inb(KBC_STATUS);
                  if (c & KBC_OUTPUT_FULL) {
                      (void) inb(KBC_DATA);
                  }
                  else if (!(c & KBC_OUTPUT_FULL)) {
                      outb(KBC_COMMAND, KBC_RESET);
                      break;
                  }
              }
          }
  
          __asm__ volatile ("int3"); /* Cause a tripple fault. Won't return. */
      }
  }
  
  static x86_reboot_t reboot_fun;
  static bool reboot_twice;
  
  void reboot(void)
  {
      __asm__ volatile ("cli");
      if (!reboot_twice) {
          reboot_twice = true;
          if (reboot_fun) {
              reboot_fun();
          }
      }
      x86_kbc_reboot();
  }
  
  void x86_set_reboot_fun(x86_reboot_t fun)
  {
      reboot_fun = fun;
  }
  
  static x86_shutdown_t shutdown_fun;
  
  bool x86_shutdown(void)
  {
      if (!shutdown_fun) {
          return false;
      }
      return shutdown_fun();
  }
  
  void x86_set_shutdown_fun(x86_shutdown_t fun)
  {
      shutdown_fun = fun;
  }