[U-Boot-Users] CONFIG_MEM_INIT_VALUE == 0xDeadBeef

[U-Boot-Users] CONFIG_MEM_INIT_VALUE == 0xDeadBeef

[robert lazarski]

Hi all, is this an english language pun ?

#define CONFIG_MEM_INIT_VALUE            0xDeadBeef

I see that the #DEFINE is used in SPD:

cpu/mpc85xx/spd_sdram.c:      ddr->sdram_data_init = CONFIG_MEM_INIT_VALUE;

I'm porting my board which has the mpc8548e and the same exact DDR2
that the CDS reference board has. I'm using SPD in my code. The CDS
board has DeadBeef assigned to  CONFIG_MEM_INIT_VALUE. I don't have a
CDS board to test. My board will arrive in a few weeks - I'm trying to
prepare the best I can. Should I leave CONFIG_MEM_INIT_VALUE as is or
will this make my board DeadBeef ?

Thanks,
Robert

[U-Boot-Users] CONFIG_MEM_INIT_VALUE == 0xDeadBeef

[Jon Loeliger]

On Tue, 2007-07-17 at 12:22, robert lazarski wrote:
> Hi all,

OK, enough of this "all" pretense! :-)  You're talking to me...

>  is this an english language pun ?
> 
> #define CONFIG_MEM_INIT_VALUE            0xDeadBeef

*sigh*  Guilty as charged, I'm afraid.

> I see that the #DEFINE is used in SPD:
> 
> cpu/mpc85xx/spd_sdram.c:      ddr->sdram_data_init = CONFIG_MEM_INIT_VALUE;
> 
> I'm porting my board which has the mpc8548e and the same exact DDR2
> that the CDS reference board has. I'm using SPD in my code. The CDS
> board has DeadBeef assigned to  CONFIG_MEM_INIT_VALUE. I don't have a
> CDS board to test. My board will arrive in a few weeks - I'm trying to
> prepare the best I can. Should I leave CONFIG_MEM_INIT_VALUE as is or
> will this make my board DeadBeef ?

The actual value is not important.  It is nominally a
non-zero, non-FF but known "poison" value.  It is merely
used to initialize memory to a known value by using the
built-in DDR controller (CONFIG_ECC_INIT_VIA_DDRCONTROLLER).
You don't have to do so if you don't want to, of course.

jdl

[U-Boot-Users] CONFIG_MEM_INIT_VALUE == 0xDeadBeef

[David Frascone]

I love fun MAGIC's.  I usually use one of the following:

0xDeadBeef
0xBaadFood
0xDeadBabe
0xF00BaaF00

-Dave

On 7/17/07, Jon Loeliger <jdl@freescale.com> wrote:
>
> On Tue, 2007-07-17 at 12:22, robert lazarski wrote:
> > Hi all,
>
> OK, enough of this "all" pretense! :-)  You're talking to me...
>
> >  is this an english language pun ?
> >
> > #define CONFIG_MEM_INIT_VALUE            0xDeadBeef
>
> *sigh*  Guilty as charged, I'm afraid.
>
> > I see that the #DEFINE is used in SPD:
> >
> > cpu/mpc85xx/spd_sdram.c:      ddr->sdram_data_init =
> CONFIG_MEM_INIT_VALUE;
> >
> > I'm porting my board which has the mpc8548e and the same exact DDR2
> > that the CDS reference board has. I'm using SPD in my code. The CDS
> > board has DeadBeef assigned to  CONFIG_MEM_INIT_VALUE. I don't have a
> > CDS board to test. My board will arrive in a few weeks - I'm trying to
> > prepare the best I can. Should I leave CONFIG_MEM_INIT_VALUE as is or
> > will this make my board DeadBeef ?
>
> The actual value is not important.  It is nominally a
> non-zero, non-FF but known "poison" value.  It is merely
> used to initialize memory to a known value by using the
> built-in DDR controller (CONFIG_ECC_INIT_VIA_DDRCONTROLLER).
> You don't have to do so if you don't want to, of course.
>
> jdl
>
>
>
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>



-- 
David Frascone

Philosophy: unintelligible answers to insoluble problems
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[U-Boot-Users] CONFIG_MEM_INIT_VALUE == 0xDeadBeef

[Jon Loeliger]

On Tue, 2007-07-17 at 13:36, David Frascone wrote:
> I love fun MAGIC's.  I usually use one of the following:
> 
> 0xDeadBeef
> 0xBaadFood
> 0xDeadBabe
> 0xF00BaaF00
> 
> -Dave

Now don't forget the ever-popular 0xCafeBabe.
And watch out for the 0xCafeD00d too!

jdl

[U-Boot-Users] CONFIG_MEM_INIT_VALUE == 0xDeadBeef

[Scott Wood]

Jon Loeliger wrote:
> On Tue, 2007-07-17 at 13:36, David Frascone wrote:
> 
>>I love fun MAGIC's.  I usually use one of the following:
>>
>>0xDeadBeef
>>0xBaadFood
>>0xDeadBabe
>>0xF00BaaF00
>>
>>-Dave
> 
> 
> Now don't forget the ever-popular 0xCafeBabe.
> And watch out for the 0xCafeD00d too!

What, no 0xdeadc0de?  Of course, one can also 0xfeedface some 0xc0cac01a 
and 0x31337a1e.

-Scott