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

Wolfgang Denk
2008-03-20T11:16:38Z

In message <200803201129.06602.sr@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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