[U-Boot] Is it possible to use 2GB or DDR on MPC834x?

[U-Boot] Is it possible to use 2GB or DDR on MPC834x?

[Valeriy Glushkov]

Hi Guys!

On my mpc8347 based board I can access 1GB of DDR with mapping 4 of 256MB 
ranges via IBAT\DBAT registers.

But with the 2 GB of DDR it's impossible to map them with BATs (there are 
only 8 BATs in the e300 core and the rest 4 of them are already used).

All the mpc83xx examples in the U-boot tree seem to use <=1GB of SDRAM, so 
they use BATs to map them.

Any suggestions are highly appreciated.

Best regards,
Valeriy Glushkov

[U-Boot] Is it possible to use 2GB or DDR on MPC834x?

[Scott Wood]

Valeriy Glushkov wrote:
> Hi Guys!
> 
> On my mpc8347 based board I can access 1GB of DDR with mapping 4 of 256MB 
> ranges via IBAT\DBAT registers.
> 
> But with the 2 GB of DDR it's impossible to map them with BATs (there are 
> only 8 BATs in the e300 core and the rest 4 of them are already used).
> 
> All the mpc83xx examples in the U-boot tree seem to use <=1GB of SDRAM, so 
> they use BATs to map them.
> 
> Any suggestions are highly appreciated.

Why do you need to access all 2GB from u-boot?

-Scott

[U-Boot] Is it possible to use 2GB of DDR on MPC834x?

[Valeriy Glushkov]

Hi,

> Why do you need to access all 2GB from u-boot?

I need only to recognize the real memory size and pass the value to Linux.

If I return the real value 2GB from my initdram() U-boot does not like that 
and resets the board.

Our devices have to support different DDR types and sizes (512/1024/2048 
MB), so U-boot is responsible for DDR init and reporting its size to 
Linux...

[U-Boot] Is it possible to use 2GB of DDR on MPC834x?

[Valeriy Glushkov]

Hi All,

The problem has been solved with defining of the following in the board 
config file:
#define CONFIG_VERY_BIG_RAM
#define CONFIG_MAX_MEM_MAPPED   ((phys_size_t)1024 << 20)

After that Linux recognizes all the DDR memory, while U-boot runs well using 
the first 1GB of it.

Best regards,
Valeriy Glushkov

----- Original Message ----- 
From: "Valeriy Glushkov" <gvv@lstec.com>
To: <u-boot@lists.denx.de>
Sent: 5 ?????? 2009 ?. 14:09
Subject: Re: [U-Boot] Is it possible to use 2GB of DDR on MPC834x?


> Hi,
>
>> Why do you need to access all 2GB from u-boot?
>
> I need only to recognize the real memory size and pass the value to Linux.
>
> If I return the real value 2GB from my initdram() U-boot does not like 
> that
> and resets the board.
>
> Our devices have to support different DDR types and sizes (512/1024/2048
> MB), so U-boot is responsible for DDR init and reporting its size to
> Linux...
>
> From your answer I understand that U-boot does not support >1GB of memory
> for MPC83xx. Is it correct?
>
> Best regards,
> Valeriy Glushkov
>
>
> ----- Original Message ----- 
> From: "Scott Wood" <scottwood@freescale.com>
> To: "Valeriy Glushkov" <gvv@lstec.com>
> Cc: <u-boot@lists.denx.de>
> Sent: 30 ??????? 2008 ?. 18:45
> Subject: Re: [U-Boot] Is it possible to use 2GB or DDR on MPC834x?
>
>
>> Valeriy Glushkov wrote:
>>> Hi Guys!
>>>
>>> On my mpc8347 based board I can access 1GB of DDR with mapping 4 of 
>>> 256MB
>>> ranges via IBAT\DBAT registers.
>>>
>>> But with the 2 GB of DDR it's impossible to map them with BATs (there 
>>> are
>>> only 8 BATs in the e300 core and the rest 4 of them are already used).
>>>
>>> All the mpc83xx examples in the U-boot tree seem to use <=1GB of SDRAM,
>>> so they use BATs to map them.
>>>
>>> Any suggestions are highly appreciated.
>>
>> Why do you need to access all 2GB from u-boot?
>>
>> -Scott
>
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