acpi_hw_read
acpi_status acpi_hw_read(u64 *value, struct acpi_generic_address *reg);
acpi_hw_read(&value64, &acpi_gbl_FADT.xpm2_control_block);
status = acpi_hw_read(&value64, &acpi_gbl_FADT.xpm_timer_block);
acpi_hw_read(&read_value64,
status = acpi_hw_read(&value64, register_a);
status = acpi_hw_read(&value64, register_b);
status = acpi_hw_read(&timer_value, &acpi_gbl_FADT.xpm_timer_block);
status = acpi_hw_read(return_value, reg);