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// Copyright (C) 2024 Intel Corporation.
// Author(s): Zhao Liu <zhao1.liu@intel.com>
// SPDX-License-Identifier: GPL-2.0-or-later
use std::ptr::addr_of_mut;
use qemu_api::{cell::bql_locked, zeroable::Zeroable};
/// Each `HPETState` represents a Event Timer Block. The v1 spec supports
/// up to 8 blocks. QEMU only uses 1 block (in PC machine).
const HPET_MAX_NUM_EVENT_TIMER_BLOCK: usize = 8;
#[repr(C, packed)]
#[derive(Copy, Clone, Default)]
pub struct HPETFwEntry {
pub event_timer_block_id: u32,
pub address: u64,
pub min_tick: u16,
pub page_prot: u8,
}
unsafe impl Zeroable for HPETFwEntry {}
#[repr(C, packed)]
#[derive(Copy, Clone, Default)]
pub struct HPETFwConfig {
pub count: u8,
pub hpet: [HPETFwEntry; HPET_MAX_NUM_EVENT_TIMER_BLOCK],
}
unsafe impl Zeroable for HPETFwConfig {}
#[allow(non_upper_case_globals)]
#[no_mangle]
pub static mut hpet_fw_cfg: HPETFwConfig = HPETFwConfig {
count: u8::MAX,
..Zeroable::ZERO
};
impl HPETFwConfig {
pub(crate) fn assign_hpet_id() -> Result<usize, &'static str> {
assert!(bql_locked());
// SAFETY: all accesses go through these methods, which guarantee
// that the accesses are protected by the BQL.
let mut fw_cfg = unsafe { *addr_of_mut!(hpet_fw_cfg) };
if fw_cfg.count == u8::MAX {
// first instance
fw_cfg.count = 0;
}
if fw_cfg.count == 8 {
Err("Only 8 instances of HPET are allowed")?;
}
let id: usize = fw_cfg.count.into();
fw_cfg.count += 1;
Ok(id)
}
pub(crate) fn update_hpet_cfg(hpet_id: usize, timer_block_id: u32, address: u64) {
assert!(bql_locked());
// SAFETY: all accesses go through these methods, which guarantee
// that the accesses are protected by the BQL.
let mut fw_cfg = unsafe { *addr_of_mut!(hpet_fw_cfg) };
fw_cfg.hpet[hpet_id].event_timer_block_id = timer_block_id;
fw_cfg.hpet[hpet_id].address = address;
}
}
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