Re: Xscale PXA255 CE.NET 4.2: Getting OEMGetExtensionDRAM to work ?

From: K. S. Huang (ks_huang_at_alphanetworks.com.remove.this)
Date: 07/30/04 

Date: Sat, 31 Jul 2004 02:47:46 +0800

I may gess
1) is EXP_SDRAM_BASE_C_VIRTUAL overlapped with oether entry in
OEMAddressTable (maybe other peripheral, flash etc)
2) is the SDRAM register (mdcnfg and other relative register) setting
properly
you may write a piece of memory sizing code (Write something and read it
back) in eboot or OAL (OEMInit or OEMGetExtensionDRAM) to make sure all of
the SDRAM can be accessed properly.
"AMScholan" <ams@plextek.co.uk>
???????:e4a0dafc.0407280755.57b5e12e@posting.google.com...
> I have a custom platform based on Intel PXA255 Xscale processor which
> is normally shipped with 64Mb of SDRAM. All of the .BIB files are set
> up to reflect this and the platform is stable using this 64Mb setup.
>
> The platform can be expanded with a further 64Mb of SDRAM. Although
> this is physically contiguous with the standard fit memory, it is
> necessary that the WinCE image can work on both the 64Mb device, or
> the 128Mb device.
>
> I am trying to implement the OEMGetExtensionDRAM() to inform the
> kernel of the existence of the (tested as working) extra 64Mb, if it
> is present.
>
> The kernel hangs very quickly with the following output:
>
> Loaded symbols for
'E:\WINCE420\PUBLIC\TESTV5\RELDIR\CT4000_ARMV4IDEBUG\NK.EXE'
> 0 PID:0 TID:0 Booting Windows CE version 4.20 for (ARM)
> 0 PID:0 TID:0 &pTOC = 8010a6ac, pTOC = 80be901c, pTOC->ulRamFree
> = 80d75000, MemForPT = 00000000
> 0 PID:0 TID:0
> Old or invalid version stamp in kernel structures - starting clean!
> 0 PID:0 TID:0 Configuring: Primary pages: 12095, Secondary
> pages: 16380, Filesystem pages = 14237
> 0 PID:0 TID:0
> Booting kernel with clean memory configuration:
> 0 PID:0 TID:0 Memory Sections:
> 0 PID:0 TID:0 [0] : start: 80d76000, extension: 00003000,
> length: 02f3f000
> 0 PID:0 TID:0 [1] : start: 84000000, extension: 00004000,
> length: 03ffc000
> 0 PID:0 TID:0 Sp=ffffc7cc
> 2 PID:0 TID:0 Windows CE KernelInit
>
> This looks to me to be fairly promising, as the two correct memory
> sections are reported, but the kernel has hung in function
> InitMemoryPool() when it is processing the new memory section. It
> would appear that a DataAbort exception is being generated.
>
> My implementation of OEMGetExtensionDRAM is:
>
> BOOL OEMGetExtensionDRAM(LPDWORD lpMemStart, LPDWORD lpMemLen)
> {
> volatile MEMC_STRUCT *v_pMEMC
> = (volatile MEMC_STRUCT *)MEMC_BASE_U_VIRTUAL;
> BOOL retVal = FALSE;
>
> /* The kernel POST detects whether there is 64Mb or 128Mb. If the
> * extra 64Mb (128Mb fit) is found it enables this bank in the
> * memory controller. We peek at the memory configuration register
> * to see if this is enabled.
> */
> if( ( v_pMEMC->mdcnfg & MDCNFG_DE1 ) != 0 )
> {
> *lpMemStart = EXP_SDRAM_BASE_C_VIRTUAL;
> *lpMemLen = (64L*1024L*1024L);
> retVal = TRUE;
> }
> return retVal;
> }
>
> I have made sure that the OEMAddressTable contains an entry for the
> expansion RAM:
>
> OEMAddressTable
>
> ;========================================================================
> ; Virtual(cached) Phys Addr Size (in MB)
> dcd SDRAM_BASE_C_VIRTUAL, SDRAM_BASE_PHYSICAL, 64
> ; 8000 0000 A000 0000
> dcd EXP_SDRAM_BASE_C_VIRTUAL, EXP_SDRAM_BASE_PHYSICAL, 64
> ; 8400 0000 A400 0000
> .
> .
> .
> dcd 0x00000000, 0x00000000, 0
> ; End of Table (MB MUST BE ZERO!)
>
> Any help would be greatly appreciated.
> Regards,
> Andrew.

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