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//! A pure-Rust #![no_std] crate for parsing Flattened Devicetrees,
//! with the goal of having a very ergonomic and idiomatic API.

#![no_std]
#![allow(missing_docs)]
pub struct MachineFdt<'a>(fdt::Fdt<'a>);
pub mod kernel_nodes;
pub use fdt::standard_nodes::Cpu;
pub use kernel_nodes::*;

mod parsing;

static mut MY_FDT_PTR: Option<*const u8> = None;

lazy_static::lazy_static! {
    static ref MY_MACHINE_FDT: MachineFdt<'static> =
        unsafe {init_from_ptr(MY_FDT_PTR.unwrap())};
}

pub fn get_fdt_ptr() -> Option<*const u8> {
    unsafe { MY_FDT_PTR }
}

/// # Safety
/// This function is unsafe because it dereferences a raw pointer.
pub unsafe fn init_fdt_ptr(virt_addr: *const u8) {
    MY_FDT_PTR = Some(virt_addr);
}

/// Init the DTB root, call after dtb finish mapping
unsafe fn init_from_ptr(virt_addr: *const u8) -> MachineFdt<'static> {
    MachineFdt(fdt::Fdt::from_ptr(virt_addr).unwrap())
}

/// Root Node found model or first compatible
pub fn machin_name() -> &'static str {
    let root_node = MY_MACHINE_FDT.0.root();
    let model = root_node
        .properties()
        .find(|p| p.name == "model")
        .and_then(|p| {
            core::str::from_utf8(p.value)
                .map(|s| s.trim_end_matches('\0'))
                .ok()
        });

    if let Some(name) = model {
        name
    } else {
        root_node.compatible().first()
    }
}

/// Searches for a node which contains a `compatible` property and contains
/// one of the strings inside of `with`
pub fn find_compatible_node(
    with: &'static [&'static str],
) -> impl Iterator<Item = fdt::node::FdtNode<'static, 'static>> {
    MY_MACHINE_FDT.0.all_nodes().filter(|n| {
        n.compatible()
            .and_then(|compats| compats.all().find(|c| with.contains(c)))
            .is_some()
    })
}

pub fn bootargs() -> Option<&'static str> {
    MY_MACHINE_FDT.0.chosen().bootargs()
}

pub fn fdt_size() -> usize {
    MY_MACHINE_FDT.0.total_size()
}

pub fn memory_nodes() -> impl Iterator<Item = Memory> {
    MY_MACHINE_FDT
        .0
        .find_all_nodes("/memory")
        .map(|m| kernel_nodes::Memory { node: m })
}

pub fn pcsi() -> Option<kernel_nodes::Pcsi> {
    MY_MACHINE_FDT
        .0
        .find_node("/psci")
        .map(|n| kernel_nodes::Pcsi { node: n })
}

pub fn cpus() -> impl Iterator<Item = fdt::standard_nodes::Cpu<'static, 'static>> {
    MY_MACHINE_FDT.0.cpus()
}