[U-Boot] Help!Some memory doesn't work on PPC405Ex based board!

[SunNeo]

Stefan and Grant,

 

I have made some progess, Linux can boot normally with 1 GB memory now.
The following is what I did:
1.Chang "Maximum low memory size" from 0x30000000(768M) to 0x20000000(512M) and enable High Memory support for Linux kernel configuration.
2.Add "CONFIG_VERY_BIG_RAM" to U-Boot configuration file, or change U-Boot Env. variable "initrd_high" from 0x30000000 to 0x20000000. This step is to make sure Linux can find ramdisk and I don't think it's critical for my issue.


Now, my question is do you think I have found root cause of my issue? I mean incorrect setting of "Maximum low memory size".

 

Best Regards,

Sun
 
> From: sr at denx.de
> To: u-boot at lists.denx.de
> Subject: Re: [U-Boot] Help!Some memory doesn't work on PPC405Ex based board!
> Date: Thu, 23 Apr 2009 11:55:35 +0200
> CC: sunwx2001 at hotmail.com; support at amcc.com; gerickson at nuovations.com
> 
> On Thursday 23 April 2009, SunNeo wrote:
> > Have performed a slow memory post using code in post/drivers/memory.c,
> > still no error.
> 
> Another idea: Did you also try using DDR autocalibration method A? Standard is 
> method B but A takes a lot longer. (See the Method_A and Method_B algorithm 
> discription in the file cpu/ppc4xx/4xx_ibm_ddr2_autocalib.c). Perhaps this 
> gives some further results.
> 
> > I found memsize in post/driver/memory.c has a limit of 
> > 256MB, so I modify it to 1024M.
> >
> >
> > Have tried Linux-2.6.29, same result.
> 
> Hmmm. You should perhaps try to debug further where exactly this error is 
> occurring. Via printk's or JTAG debugger. If this error always happens at the 
> same location it could perhaps be located (if it's not a memory problem) in 
> the kernel source code.
> 
> Best regards,
> Stefan
> 
> =====================================================================
> DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: office at denx.de
> =====================================================================

_________________________________________________________________
上Windows Live 中国首页，下载最新版Messenger！
http://www.windowslive.cn