drivers/acpi/reboot.c

   1
   2 #include <linux/pci.h>
   3 #include <linux/acpi.h>
   4 #include <acpi/reboot.h>
   5
   6 void acpi_reboot(void)
   7 {
   8         struct acpi_generic_address *rr;
   9         struct pci_bus *bus0;
  10         u8 reset_value;
  11         unsigned int devfn;
  12
  13         if (acpi_disabled)
  14                 return;
  15
  16         rr = &acpi_gbl_FADT.reset_register;
  17
  18         /* Is the reset register supported? */
  19         if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER) ||
  20             rr->bit_width != 8 || rr->bit_offset != 0)
  21                 return;
  22
  23         reset_value = acpi_gbl_FADT.reset_value;
  24
  25         /* The reset register can only exist in I/O, Memory or PCI config space
  26          * on a device on bus 0. */
  27         switch (rr->space_id) {
  28         case ACPI_ADR_SPACE_PCI_CONFIG:
  29                 /* The reset register can only live on bus 0. */
  30                 bus0 = pci_find_bus(0, 0);
  31                 if (!bus0)
  32                         return;
  33                 /* Form PCI device/function pair. */
  34                 devfn = PCI_DEVFN((rr->address >> 32) & 0xffff,
  35                                   (rr->address >> 16) & 0xffff);
  36                 printk(KERN_DEBUG "Resetting with ACPI PCI RESET_REG.");
  37                 /* Write the value that resets us. */
  38                 pci_bus_write_config_byte(bus0, devfn,
  39                                 (rr->address & 0xffff), reset_value);
  40                 break;
  41
  42         case ACPI_ADR_SPACE_SYSTEM_MEMORY:
  43         case ACPI_ADR_SPACE_SYSTEM_IO:
  44                 printk(KERN_DEBUG "ACPI MEMORY or I/O RESET_REG.\n");
  45                 acpi_hw_low_level_write(8, reset_value, rr);
  46                 break;
  47         }
  48         /* Wait ten seconds */
  49         acpi_os_stall(10000000);
  50 }