cpu_cache_nop_range
void (*cpu_dcache_wbinv_range)(vaddr_t, vsize_t) = cpu_cache_nop_range;
void (*cpu_dcache_inv_range)(vaddr_t, vsize_t) = cpu_cache_nop_range;
void (*cpu_dcache_wb_range)(vaddr_t, vsize_t) = cpu_cache_nop_range;