ostd 0.8.4

Rust OS framework that facilitates the development of and innovation in OS kernels
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// SPDX-License-Identifier: MPL-2.0

//! Provides CMOS I/O port access.
//!
//! "CMOS" is a tiny bit of very low power static memory that lives on the same chip as the Real-Time Clock (RTC).
//!
//! Reference: <https://wiki.osdev.org/CMOS>
//!

#![allow(unused_variables)]

use acpi::{fadt::Fadt, sdt::Signature};
use x86_64::instructions::port::{ReadOnlyAccess, WriteOnlyAccess};

use super::io_port::IoPort;
use crate::arch::x86::kernel::acpi::ACPI_TABLES;

/// CMOS address I/O port
pub static CMOS_ADDRESS: IoPort<u8, WriteOnlyAccess> = unsafe { IoPort::new(0x70) };

/// CMOS data I/O port
pub static CMOS_DATA: IoPort<u8, ReadOnlyAccess> = unsafe { IoPort::new(0x71) };

/// Gets the century register location. This function is used in RTC(Real Time Clock) module initialization.
pub fn century_register() -> Option<u8> {
    if !ACPI_TABLES.is_completed() {
        return None;
    }
    unsafe {
        match ACPI_TABLES
            .get()
            .unwrap()
            .lock()
            .get_sdt::<Fadt>(Signature::FADT)
        {
            Ok(a) => Some(a.unwrap().century),
            Err(er) => None,
        }
    }
}