hpet.rs

use core::{mem, ptr};

use super::sdt::Sdt;

#[repr(packed)]
#[derive(Clone, Copy, Debug, Default)]
pub struct GenericAddressStructure {
    address_space: u8,
    bit_width: u8,
    bit_offset: u8,
    access_size: u8,
    pub address: u64,
}

#[repr(packed)]
#[derive(Debug)]
pub struct Hpet {
    pub header: Sdt,

    pub hw_rev_id: u8,
    pub comparator_descriptor: u8,
    pub pci_vendor_id: u16,

    pub base_address: GenericAddressStructure,

    pub hpet_number: u8,
    pub min_periodic_clk_tick: u16,
    pub oem_attribute: u8
}

impl Hpet {
    pub fn new(sdt: &'static Sdt) -> Option<Hpet> {
        if &sdt.signature == b"HPET" && sdt.length as usize >= mem::size_of::<Hpet>() {
            Some(unsafe { ptr::read((sdt as *const Sdt) as *const Hpet) })
        } else {
            None
        }
    }
}