[U-Boot-Users] [PATCH] ppc4xx: Don't use last 256 bytes of SDRAM, workaround for 440EPx CHIP 11 errata

[Wolfgang Denk]

In message <200803201129.06602.sr at denx.de> you wrote:
> 
> I don't like this either. But I have not come up with a "generic" solution 
> till now. It's not so easy since the 440EPx SDRAM setup code is sometimes 
> common (cpu/ppc4xx/denali_spd_ddr2.c) and sometimes board specific. And it 
> gets even more complicated when ECC initialization is needed too. So 
> currently I have no "better" solution as to do it in a board specific way.
> 
> As always, patches implementing a "better" more generic solution are welcome.

At the cost of an #ifdef, this could be added to the memory
reservation code in "lib_ppc/board.c", i. e. somewhere after

 ...
 427          * Reserve memory at end of RAM for (top down in that order):
 428          *  - kernel log buffer
 429          *  - protected RAM
 430          *  - LCD framebuffer
 431          *  - monitor code
 432          *  - board info struct
 433          */
 434         len = (ulong)&_end - CFG_MONITOR_BASE;
 435
 436         addr = CFG_SDRAM_BASE + get_effective_memsize();

Of course you need to make sure that  the  linux  kernel  understands
this changed behaviour / shifted addresses, too.

Best regards,

Wolfgang Denk

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