RE: 440GX MMU problem

RE: 440GX MMU problem

[VanBaren, Gerald (AGRE)]

> -----Original Message-----
> From: linuxppc-embedded-bounces@ozlabs.org=0D
> [mailto:linuxppc-embedded-bounces@ozlabs.org] On Behalf Of=0D
> Barbier, Renaud (GE Infrastructure)
> Sent: Friday, December 03, 2004 3:53 PM
> To: Matt Porter
> Cc: linuxppc-embedded@ozlabs.org
> Subject: RE: 440GX MMU problem
>=0D
> actually, I just loaded linux at memory offset=0D
> 0x10000000(above 256MB) and in this case it is able to boot=0D
> and use the full 512MB.
> there maybe indeed something broken.
>=0D
> Originally, U-boot did not map the full 512MB but only 256MB.
> I wonder if that could be a possible source of my problem.

Disclaimer: I don't have experience with the 4xx family, but won't stop
me from speculating (which drives Wolfgang crazy when I guess wrong ;-).

On the 82xx u-boot uses BATs to map memory.  On the 82xx, BATs are
limited to 256MBytes per BAT.  I'm guessing you are running into this.
Somewhere in your u-boot it doesn't know how to go beyond the 256MByte
boundary.

On u-boot, check out the use of "CONFIG_VERY_BIG_RAM".  It doesn't look
like it applies directly to your board/processor, but you may be able to
enhance your system using it or a similar concept.

gvb


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(Very) Simple question(s) compared to group topics

[Bora Þahin]

Hi,

  I was subscribed to list a few days ago. I dont know this group is eligible for my very simple or
  basic questions compared to list topics. In one side asm codes is discussed like one jump command
  why not reach to symbol and the other side interrupt handling routines is discussed like whether
  or not critical interrupt handling is used in 405 EP. Subsequently, my simple question is to stay
  very basic. However if i get an answer(s) or redirections to correct places, I can be very
  grateful.

  A bit summary about me...
  
  So far, let say until the last one week or a bit over, I havent done any work out of x86 including
  any RISC cpu. I know inner workings of x86(asm) like segmentation, paging, booting etc. not to be
  very detailed. Before, I have dealt with mem. mag. especially in the means of mm initialization,
  booting, ...etc on the x86 imp. of the Linux kernel.

  The subject...

  PPC and 4xx series of it is absolutely new to me. We think to decode "mpeg 4/level 5" coded films
  on the 4xx series of ppc if it is possible. I examined a bit these cpus. 4xx series go to 700/800
  MHZ clock freq but most of them dont contain floating point unit.(Only one of them has fpu if my
  memory dont serve me. I cant say it is connected. If i understand the doc correctly, you can
  connect a fpu to the system) This is just a point. I know clock freq is not alone on the cpu
  performance. I would like to hear experianced users testimonals or thought about decoding of mpeg
  performance of these cpus...

-- 
Bora Sahin
borasahin.port5.com

Re: (Very) Simple question(s) compared to group topics

[Mark Chambers]

If you go by MIPS, it takes very approximately 1000MIPS to decode DVD
quality MPEG2.
I don't think floating point helps with MPEG2, not sure about MPEG4.  You
also have to
think about memory bandwidth with an application like video.  All settop box
designs that
I'm aware of have some kind of MPEG decode coprocessor, either a separate
chip or built
into the main processor (like ATI Xilleon).

Mark Chambers
wvcomputronics.com

----- Original Message ----- 
From: "Bora Þahin" <bora.sahin@ttnet.net.tr>
To: <linuxppc-embedded@ozlabs.org>
Sent: Saturday, December 04, 2004 9:04 AM
Subject: (Very) Simple question(s) compared to group topics


> Hi,
>
>   I was subscribed to list a few days ago. I dont know this group is
eligible for my very simple or
>   basic questions compared to list topics. In one side asm codes is
discussed like one jump command
>   why not reach to symbol and the other side interrupt handling routines
is discussed like whether
>   or not critical interrupt handling is used in 405 EP. Subsequently, my
simple question is to stay
>   very basic. However if i get an answer(s) or redirections to correct
places, I can be very
>   grateful.
>
>   A bit summary about me...
>
>   So far, let say until the last one week or a bit over, I havent done any
work out of x86 including
>   any RISC cpu. I know inner workings of x86(asm) like segmentation,
paging, booting etc. not to be
>   very detailed. Before, I have dealt with mem. mag. especially in the
means of mm initialization,
>   booting, ...etc on the x86 imp. of the Linux kernel.
>
>   The subject...
>
>   PPC and 4xx series of it is absolutely new to me. We think to decode
"mpeg 4/level 5" coded films
>   on the 4xx series of ppc if it is possible. I examined a bit these cpus.
4xx series go to 700/800
>   MHZ clock freq but most of them dont contain floating point unit.(Only
one of them has fpu if my
>   memory dont serve me. I cant say it is connected. If i understand the
doc correctly, you can
>   connect a fpu to the system) This is just a point. I know clock freq is
not alone on the cpu
>   performance. I would like to hear experianced users testimonals or
thought about decoding of mpeg
>   performance of these cpus...
>
> -- 
> Bora Sahin
> borasahin.port5.com
>
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded

Re: (Very) Simple question(s) compared to group topics

[Jon Masters]

On Sat, 4 Dec 2004 10:08:42 -0500, Mark Chambers <markc@mail.com> wrote:

> All settop box designs that
> I'm aware of have some kind of MPEG decode coprocessor

IBM have a reference board based on 4xx which does just this -
although the drivers are disputedly non-GPL (there's a campaign
website about that at this point).

Jon.