oh, wait, i think i just answered some of my questions based on this snippet from common/env_nvram.c:
/* * Initialize Environment use * * We are still running from ROM, so data use is limited */ int env_init(void) { #if defined(CONFIG_SYS_NVRAM_ACCESS_ROUTINE) ulong crc; uchar data[ENV_SIZE];
nvram_read(&crc, CONFIG_ENV_ADDR, sizeof(ulong)); nvram_read(data, CONFIG_ENV_ADDR + sizeof(ulong), ENV_SIZE);
if (crc32(0, data, ENV_SIZE) == crc) { gd->env_addr = (ulong)CONFIG_ENV_ADDR + sizeof(long); #else if (crc32(0, env_ptr->data, ENV_SIZE) == env_ptr->crc) { gd->env_addr = (ulong)&env_ptr->data; #endif gd->env_valid = 1; } else { gd->env_addr = (ulong)&default_environment[0]; gd->env_valid = 0; }
return 0; }
so if there is a valid environment at the address specified by the board header file, it's used, otherwise fall back to default_environment[]. i had suspected it was something like that, i just hadn't found the code yet.
is this written up somewhere?
rday
p.s. how does the default environment get to the CONFIG_ENV_ADDR defined in the board header file? is that done automatically when u-boot starts to run and notices that there is no valid environment info at that address, and therefore copies it for you?
i will keep reading the source.