[U-Boot-Users] Questions about the U-Boot README, esp. CFG_IMMR
I got another question
About CFG_IMMR the README says: DO NOT CHANGE! (MPC8xx systems only)
This confuses me. As the IMMR is a SPR (special purpose register) in the MPC8xx, assigning it an address seems to make no sense.
Nevertheless CFG_IMMR is used everywhere in the U-Boot code, so there must be a preset for it, which I can't find in the source. Also, almost any config in include/configs sets this to 0xFF000000. So what is it good for and what should I choose?
Peter Asemann
In message 41B6EC48.8050909@web.de you wrote:
About CFG_IMMR the README says: DO NOT CHANGE! (MPC8xx systems only)
This is a bit of strong language to scare off thos who don't unterstand what they are doing.
This confuses me. As the IMMR is a SPR (special purpose register) in the MPC8xx, assigning it an address seems to make no sense.
Read this as: special register which holds the address of the Internem Memory.
Nevertheless CFG_IMMR is used everywhere in the U-Boot code, so there must be a preset for it, which I can't find in the source. Also, almost
RTFM - the 'M' is the MPC8xx User's Manual here.
any config in include/configs sets this to 0xFF000000. So what is it good for and what should I choose?
This depends on the memory map you chose for your board. Remember: it's _you_ who defines the memory map.
Best regards,
Wolfgang Denk
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Peter Asemann -
Wolfgang Denk