#![no_std]

use core::mem::transmute;
use matcha_hal::dprintf;

pub mod elf_loader;
pub mod tar_loader;

pub const SMC_CONTROL_BLOCK: *mut u32 = 0x50020000 as *mut u32;

fn round_up_to_page(addr: u32) -> u32 {
    return (addr + 4095) & !4095;
}

// TODO(aappleby): Break this down into smaller pieces and move into app/main
pub fn load_sel4() {
    unsafe {
        // Look in our tar file for the ELFs we need to boot Shodan.
        let sel4_elf = elf_loader::find_elf("kernel");
        let capdl_elf = elf_loader::find_elf("capdl-loader");

        if sel4_elf.is_null() {
          dprintf!("Boot failure, seL4 kernel ELF missing.\n");
          return;
        }

        if capdl_elf.is_null() {
          dprintf!("Boot failure seL4 CapDL ELF missing.\n");
          return;
        }

        // If we found all of them, boot in Shodan mode.
        dprintf!("Loading seL4 kernel elf\n");
        elf_loader::load_elf_segments(sel4_elf.as_ref().unwrap(), 0);

        let sel4_segments = elf_loader::elf_get_segments(sel4_elf);
        let capdl_segments = elf_loader::elf_get_segments(capdl_elf);

        let sel4_pend = round_up_to_page(elf_loader::elf_phys_max(sel4_segments));

        dprintf!("Loading capdl-loader to the page after seL4\n");
        elf_loader::load_elf_segments(
            capdl_elf.as_ref().unwrap(),
            sel4_pend - elf_loader::elf_phys_min(capdl_segments),
        );

        dprintf!("Starting management core\n");

        let entry_point: u32 = (*sel4_elf).e_entry
            - (elf_loader::elf_virt_min(sel4_segments)
                - elf_loader::elf_phys_min(sel4_segments));

        let message = [
            transmute(sel4_pend),
            transmute(
                sel4_pend
                    + round_up_to_page(
                        elf_loader::elf_phys_max(capdl_segments)
                            - elf_loader::elf_phys_min(capdl_segments),
                    ),
            ),
            transmute(sel4_pend - elf_loader::elf_phys_min(capdl_segments)),
            transmute((*capdl_elf).e_entry),
        ];
        matcha_hal::mailbox::MAILBOX1.send_message(&message);
        dprintf!("seL4 boot message posted\n");

        SMC_CONTROL_BLOCK.write_volatile(entry_point);

        dprintf!("SMC started, waiting on mailbox to clear\n");

        matcha_hal::mailbox::MAILBOX1.wait_lowater(0);

        dprintf!("Mailbox cleared\n");
    }
}