• Simon Glass's avatar
    Add a simple malloc() implementation for pre-relocation · d59476b6
    Simon Glass authored
    If we are to have driver model before relocation we need to support some
    way of calling memory allocation routines.
    
    The standard malloc() is pretty complicated:
    
    1. It uses some BSS memory for its state, and BSS is not available before
    relocation
    
    2. It supports algorithms for reducing memory fragmentation and improving
    performace of free(). Before relocation we could happily just not support
    free().
    
    3. It includes about 4KB of code (Thumb 2) and 1KB of data. However since
    this has been loaded anyway this is not really a problem.
    
    The simplest way to support pre-relocation malloc() is to reserve an area
    of memory and allocate it in increasing blocks as needed. This
    implementation does this.
    
    To enable it, you need to define the size of the malloc() pool as described
    in the README. It will be located above the pre-relocation stack on
    supported architectures.
    
    Note that this implementation is only useful on machines which have some
    memory available before dram_init() is called - this includes those that
    do no DRAM init (like tegra) and those that do it in SPL (quite a few
    boards). Enabling driver model preior to relocation for the rest of the
    boards is left for a later exercise.
    Signed-off-by: default avatarSimon Glass <sjg@chromium.org>
    d59476b6
asm-offsets.c 1.13 KB