Re: linux booting fails on ppc440x5 with SRAM

[Vineeth _ <blacklites@gmail.com>]

Hi,

In arch/powerpc/kernel/head_44x.S file, it says it clears all the TLBs
except the current working one. In our case we have mainly 3 TLBs for
FLASH, SRAM and the UART. We have the TLB of 16MB of SRAM *which is
our total memory*. So the TLBs that we create from our bootloader will
be used for the entire linux operation. I am attaching the TLB
initialization code with this mail, does it make any problem ?

  li  r3,1        # Slot1 SRAM
  LOADREG_32    r4,0x0
  LOADREG_32    r6, ( TLB_I_MASK | TLB_U_RWX | TLB_S_RWX |TLB_G_MASK  )
  LOADREG_32    r5,TLB_SIZE_16M
  mr  r7,r4
  bl  Save_TLB

Vineeth _

On Mon, Oct 12, 2009 at 7:04 PM, Vineeth _ <blacklites@gmail.com> wrote:
> Hi Wolfgang,
>
> The link says about the initialization of the SDRAM; Does it
> applicable in our case, where we have SRAM on our board. Does the
> initialization means just clearing the memory in case of SRAM ? We
> tried clearing the memory before the operation which doesnt work too.
> We are creating a TLB of 16MB for the SRAM which is not cachable        .
>
> -Vineeth
>
> On Fri, Oct 9, 2009 at 5:03 PM, Wolfgang Denk <wd@denx.de> wrote:
>> Dear Vineeth _,
>>
>> In message <a9b543570910090320t1444f8f1qf4c8ab7dbbef679f@mail.gmail.com> you wrote:
>>> We ported the uboot Memory test and tested the 15MB ram and it was
>>> successful.interestingly we have only 16MB SRAM in our board.We used 1
>>
>> Such a memory test means nothing. The only thing you can learn from it
>> is that basic read and write accesses are working. You don;t get any
>> information about the behaviour for burst mode accesses from such a
>> test. See the FAQ at
>> http://www.denx.de/wiki/view/DULG/LinuxCrashesRandomly  and at
>> http://www.denx.de/wiki/DULG/UBootCrashAfterRelocation
>>
>> Best regards,
>>
>> Wolfgang Denk
>>
>> --
>> DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
>> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
>> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
>> I mean, I . . . think to understand you, I just don't know  what  you
>> are saying ...                        - Terry Pratchett, _Soul Music_
>>
>