[U-Boot-Users] yet another how-to-configure-RAM-in-u-boot question
Hi there!
I'm having quite a few problems of understanding while trying to write an U-Boot configuration for my board.
I've read in the mailing list archives and in the README... as you see, it didn't help much.
The README says (I had the impression) that the following happens when the U-Boot starts:
U-Boot maps memory banks using the preliminary mapping, tests RAM sizes, then banks of the same are mapped from 0x0 on, starting with CS#2.
So my first question is: Am I in trouble for my SDRAM bank actually is at CS #1? This seems to be what U-Boot expects, everything in the README reads like no SDRAM should be at a bank below CS#2.
Peter Asemann
Hello,
in message 429B5AAE.2050002@web.de you wrote:
U-Boot maps memory banks using the preliminary mapping, tests RAM sizes, then banks of the same are mapped from 0x0 on, starting with CS#2.
For completeness: the mapping starts at 0x0000 on PowerPC only; other architectures use other memory maps.
So my first question is: Am I in trouble for my SDRAM bank actually is at CS #1? This seems to be what U-Boot expects, everything in the README reads like no SDRAM should be at a bank below CS#2.
No, there is no such assumption - it is up to your hardware (and to your code which supports your hardare) which chip select(s) are used. The description in the README is just an example that shows what to do in case of more than one flash bank and more than one RAM bank.
If you have only one bank of flash memopry (at CS0) then it is perfectly fine to use CS1 for RAM.
Best regards,
Wolfgang Denk
participants (2)
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Peter Asemann -
Wolfgang Denk