reboot.c

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#include <linux/pci.h>
#include <linux/acpi.h>
#include <acpi/reboot.h>

void acpi_reboot(void)
{
    struct acpi_generic_address *rr;
    struct pci_bus *bus0;
    u8 reset_value;
    unsigned int devfn;

    if (acpi_disabled)
        return;

    rr = &acpi_gbl_FADT.reset_register;

    /* ACPI reset register was only introduced with v2 of the FADT */

    if (acpi_gbl_FADT.header.revision < 2)
        return;

    /* Is the reset register supported? The spec says we should be
     * checking the bit width and bit offset, but Windows ignores
     * these fields */
    if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER))
        return;

    reset_value = acpi_gbl_FADT.reset_value;

    /* The reset register can only exist in I/O, Memory or PCI config space
     * on a device on bus 0. */
    switch (rr->space_id) {
    case ACPI_ADR_SPACE_PCI_CONFIG:
        /* The reset register can only live on bus 0. */
        bus0 = pci_find_bus(0, 0);
        if (!bus0)
            return;
        /* Form PCI device/function pair. */
        devfn = PCI_DEVFN((rr->address >> 32) & 0xffff,
                  (rr->address >> 16) & 0xffff);
        printk(KERN_DEBUG "Resetting with ACPI PCI RESET_REG.");
        /* Write the value that resets us. */
        pci_bus_write_config_byte(bus0, devfn,
                (rr->address & 0xffff), reset_value);
        break;

    case ACPI_ADR_SPACE_SYSTEM_MEMORY:
    case ACPI_ADR_SPACE_SYSTEM_IO:
        printk(KERN_DEBUG "ACPI MEMORY or I/O RESET_REG.\n");
        acpi_reset();
        break;
    }
}