U-Boot/MIPS Notes

TODOs

• Little endian build
• Cache rework
• Unify all board's link directives
• Need to extend ROM exception handlers, and if console available, print panic()
• do_bootelf() issue; 1) fix dcache_disable itself or 2) insert flush_cache() before dcache_disable()

startup sequence

_start - cpu/mips/start.S
    init CP0.WATCHLO
    init CP0.WATCHHI
    init CP0.STATUS
    init CP0.CAUSE
    init CP0.COUNT
    init CP0.COMPARE
    init CP0.CONFIG
    init $gp            - used for ROM code
    jalr lowlevel_init
    jalr mips_cache_reset
    update CP0.CONFIG
    jalr mips_cache_lock - hmm.
    j board_init_f - lib_mips/board.c
            processing init_sequence[]
            calc stack;
            relocate_code() - back to cpu/mips/start.S
/*
 * relocation
 */
relocate_code:
    set $sp;
    calc new $gp        - used for *relocated codes*
    set $gp
    copy codes          - main relocation
    j in_ram            - jump to in_ram on the memory

in_ram:
    update got entries
    clear bss
    j board_init_r - lib_mips/board.c
            relocate the command table
            flash_init()
            mem_malloc_init()
            malloc_bin_reloc()
            env_relocate()
            pci_init()
            devices_init()
            jumptable_init()
            console_init_r()
            misc_init_r()
            eth_initialize()
            main_loop()