diff options
Diffstat (limited to 'drivers/acpi/reboot.c')
| -rw-r--r-- | drivers/acpi/reboot.c | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/drivers/acpi/reboot.c b/drivers/acpi/reboot.c new file mode 100644 index 000000000..a6c77e8b3 --- /dev/null +++ b/drivers/acpi/reboot.c @@ -0,0 +1,54 @@ + +#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; + } +} |