pub const RAM_BASE: usize = 0x80000000;
pub const RAM_SIZE: usize = 128 * 1024 * 1024;
pub const UART_BASE: usize = 0x10000000;
pub const VIRTIO_BASE: usize = 0x10001000;
pub const VIRTIO_SIZE: usize = 0x8000;
pub const PLIC_BASE: usize = 0x0C000000;
pub const CLINT_BASE: usize = 0x02000000;
pub const USER_POOL_BASE: usize = 0x84000000;
/// 64 MiB, up to the end of RAM (QEMU virt's default 128 MiB).
pub const USER_POOL_PAGES: usize = 16384;
pub const TICK_INTERVAL: u64 = 10_000_000;

/// QEMU virt's PLIC lines.
const UART_IRQ: u16 = 10;
const VIRTIO_IRQ_BASE: u16 = 1;
const VIRTIO_SLOT_SIZE: usize = 0x1000;
const VIRTIO_SLOTS: usize = VIRTIO_SIZE / VIRTIO_SLOT_SIZE;

pub const BOARD_DEVICES: usize = 1 + VIRTIO_SLOTS;

/// What each entry of `devices()` is, for init's BootInfo.
pub fn kinds() -> [u64; BOARD_DEVICES] {
    let mut kinds = [types::bootinfo::KIND_VIRTIO; BOARD_DEVICES];
    kinds[0] = types::bootinfo::KIND_UART_16550;
    kinds
}

/// Every device userspace may drive: the UART and each VirtIO MMIO slot.
/// The PLIC, CLINT and RAM stay the kernel's.
pub fn devices() -> Option<[kernel::BoardDevice; BOARD_DEVICES]> {
    use types::{address::PhysicalAddress, bounded::PageCount, id::IrqId};
    let one = PageCount::new(1)?;
    let device = |base: usize, irq: u16| kernel::BoardDevice {
        base: PhysicalAddress::from_raw(base),
        pages: one,
        irq: Some(IrqId::from_raw(irq)),
    };
    let mut all = [device(UART_BASE, UART_IRQ); BOARD_DEVICES];
    for (i, d) in all.iter_mut().skip(1).enumerate() {
        *d = device(
            VIRTIO_BASE + i * VIRTIO_SLOT_SIZE,
            VIRTIO_IRQ_BASE + i as u16,
        );
    }
    Some(all)
}