[U-Boot-Users] Re: ENV_IS_EMBEDDED functionality
wd at denx.de
Sat Jan 14 00:48:23 CET 2006
In message <43C82439.6030102 at comcast.net> you wrote:
> Thanks for the quick response. There are some Blackfin related questions
> on the old list, but the attempt made a couple of years ago to submit
> the patches was rejected for a lot of reasons. I was not involved at
> that time. I am attempting to determine if this ENV_IS_EMBEDDED
> approach is also going to be rejected so I can find another way. It is
Yes. Please don't invent new stuff without need. The existing code is
ugly (being a mess of #ifdef's), but serves a purpose (minimal code
footprint because all these things get computed at compile time) and
covers all existing configurations so far.
> The source of my confusion is that ENV_IS_EMBEDDED is defined as follows
> in environment.h
> #if (CFG_ENV_ADDR >= CFG_MONITOR_BASE) && \
> (CFG_ENV_ADDR+CFG_ENV_SIZE) <= (CFG_MONITOR_BASE+CFG_MONITOR_LEN)
> #define ENV_IS_EMBEDDED 1
> Isn't CFG_MONITOR_BASE the address where u-boot resides for execution?
No. It's the start address of the image in flash. As mentioned
before, this has *nothing* to do with execution.
> It is defined that way on the Blackfin code
> because CFG_MONITOR_BASE is defined as TEXT_BASE and TEXT_BASE is
> defined as 0x07FC0000. The flash
> memory is located at CFG_FLASH_BASE (defined as 0x20000000) and
> CFG_ENV_ADDR is 0x20004000. U-boot is loaded into flash at 0x20000000,
Ummm... then 0x07FC0000 must be a RAM address, right? Then your
definition of CFG_MONITOR_BASE is broken. You should have
CFG_MONITOR_BASE = 0x20000000.
> so the environment data does reside in flash even though the
> ENV_IS_EMBEDDED test fails. The code gets around this by just defining
> it directly. So is CFG_MONITOR_BASE incorrectly defined and it should be
> a flash address?? BTW the u-boot code is not compiled PIC, so the
> execution address must matc the link address.
...or you must relocate it.
Software Engineering: Embedded and Realtime Systems, Embedded Linux
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