--- 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
>
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ts-7000/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/ts-7000/join
(Yahoo! ID required)
<*> To change settings via email:
<*> To unsubscribe from this group, send an email to:
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|