[U-Boot-Users] Question about CFG_ENV_ADDR during RAMBOOT
wd at denx.de
Tue May 22 23:04:05 CEST 2007
In message <46535865.6060400 at smiths-aerospace.com> you wrote:
> Looks to me like it would be better defined:
> #define CFG_ENV_SIZE 0x2000
> #define CFG_ENV_ADDR (CFG_MONITOR_BASE - CFG_ENV_SIZE)
No, this is broken as CFG_ENV_SIZE may be (and often actually is)
smaller than CFG_ENV_SECT_SIZE
> The saving grace here is probably:
> * For a RAMBOOT image, there isn't any incentive to save lots of stuff
> in the env since it (generally) disappears on a reboot and definitely
> disappears on a power cycle.
One could argue that a correctly configured ramboot version would
access the original copy of the environment in flash. But such
discussion is void, as ramboot itself it not supported officially.
> * On the PowerPC, at least, the first 12K of u-boot.bin is the HRCW and
> vectors which aren't used by a RAMBOOT image so overwriting them is a
> non-fatal error.
Wrong. You may have timer and other interrupts, so overwriting the
exception vectors is a Bad Thing (TM).
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