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[ts-7000] Memory interfacing in TS-Linux

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Subject: [ts-7000] Memory interfacing in TS-Linux
From: Manish Varma <>
Date: Thu, 4 Jan 2007 12:33:33 -0800 (PST)
Hello,

    Can anybody guide me where I can find memory
interfacing code (for RAM and Flash) in TS-Linux..

    We are implementing VOIP phone with TI's C54CST as
DSP, and to access that we are trying to implement
HPI, and in order to access the DSP memory thru HPI we
want to find the code to interface the basic in-built
memory..

    Any help or reference to documentation for this
topic will be appritiated..

Many Thanks,

Manish Varma.



--- charliem_1216 <> wrote:

> --- In  "Breton M. Saunders"
> <> wrote:
> >
> > Hi Doug,
> > 
> >   Yes, the bug happens here.  I was running
> memtest-4.0.6 to check 
> > things were working ok.  They are not yet.
> >
> 
> > have found so far is that the high-order pages at
> physical offset 
> > 0xe0000000, 0xe1000000, 0xe4000000 and 0xe5000000
> are being mapped to 
> > virtual addresses 0xa0000000, 0xa1000000, ... 
> more by fluke than 
> > anything else.
> 
> This is by design, AFAIK, using the 4G wrap as you
> found below.
> 
> > 
> >   The calculation of a virtual address consists of
> adding PAGE_OFFSET 
> > (0xc0000000) to the physical address.  For the low
> memory 0x00000000, 
> > 0x10000000 ... this works fine, mapping the kernel
> memory in at 
> > 0xC0000000, etc...  For the high page memory
> 0xC0000000 + 0xE0000000 = 
> > 0x1A0000000 - since its a 32 bit processor, the 1
> is truncated off the 
> > front. 
> 
> Actually Lennert thought we may be able to use this
> wrap at 4G to get
> the RAM to appear within 1G, and thus not need to
> use DISCONTIGMEM. 
> Steps suggested were:
> * Change PHYS_OFFSET to 0xe0000000
> * Tell Redboot to load the kernel at 0xe0008000
> * Pass all 8 mem= tags on the command line (since
> ATAGs may not work)
> * Comment out the boot_params line in ts7250.c <--
> not sure why this
> is needed.
> 
> I tried this without success, but did not pursue it.
>  You may have
> more knowledge / time to make it work.
> 
> I also tried a DISCONTIGMEM build (_without_ the
> changes above), but
> couldn't build the kernel (undefined references). 
> Haven't tried to
> fix it.
> 
> > 
> >   If anyone knows where there is some
> documentation on implementing 
> > DISCONTIGMEM, let me know!
> > 
> >   In the meantime I am likely going to try and
> hard code the memory map 
> > using the DISCONTIGMEM macros defined in 
> > include/asm-arm/arch-ep93xx/memory.h...
> 
> I haven't had a chance to try out your patches yet,
> but I did notice
> there weren't any maps matching TS7400 / TS7250 RAM
> layout.
> 
> I heard there may be a performance penalty using
> DISCONTIGRAM.  If you
> do get a DISCONTIGRAM build up and working, can you
> look for a speed
> difference?
> 
> Thanks for the patches, that's further than I got!
> 
> > 
> >     Cheers,
> > 
> >     -Brett
> > 
> 
> Regards, ........... Charlie
> 
> > 
> 
> 


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