[U-Boot-Users] Value of CFG_PCI_MEMBASE

[U-Boot-Users] Value of CFG_PCI_MEMBASE

[Sachin Rane]

Hi,
 
In the 'include/configs/ocotea.h" file:
8<-----------------------------------------------------------------------------------------------------
 
#define CFG_PCI_MEMBASE     0x80000000      /* mapped pci memory        */
 
8<-----------------------------------------------------------------------------------------------------
 
But the Memory map of the Ocotea board (PPC440GX? Evaluation Board User's Manual) has mentioned about the PCI memory  as:
Start Address (32 Bit) - 9000 0000
End Address (32 Bit) - 9FFF FFFF 
Start Address (36 Bit) - 3 0000 0000 
End Address (36 Bit) - 3 0FFF FFFF 
Size - 256MB 256 MB 
 
 
I am not clear about the logic behind the value assigned to CFG_PCI_MEMBASE    i.e. 0x80000000
 
Can you help me to figure it out?
 
Regards,
Sachin Rane
 
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[U-Boot-Users] Value of CFG_PCI_MEMBASE

[Stefan Roese]

On Wednesday 11 June 2008, Sachin Rane wrote:
> In the 'include/configs/ocotea.h" file:
> 8<-------------------------------------------------------------------------
>----------------------------
>
> #define CFG_PCI_MEMBASE     0x80000000      /* mapped pci memory        */

This is the virtual address.

> 8<-------------------------------------------------------------------------
>----------------------------
>
> But the Memory map of the Ocotea board (PPC440GX? Evaluation Board User's
> Manual) has mentioned about the PCI memory  as: Start Address (32 Bit) -
> 9000 0000
> End Address (32 Bit) - 9FFF FFFF
> Start Address (36 Bit) - 3 0000 0000
> End Address (36 Bit) - 3 0FFF FFFF
> Size - 256MB 256 MB

The users manual referrs to the physical (36bit) address.

> I am not clear about the logic behind the value assigned to CFG_PCI_MEMBASE
>    i.e. 0x80000000

The mapping between virtual and physical address is done via the MMU. I 
suggest you take a look at the init.S file in the board directory. This 
should make it clear.

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot-Users] Value of CFG_PCI_MEMBASE

[Sachin Rane]

Hi Stefen,
 
Thanks for the reply.
 
Infact I was looking for the info to create a proper 'tlbentry' in 'init.S'
As per my understanding the 'tlbentry' is to map 32-bit address to 36-bit address.
 
The 'tlbenry' for the PCI Memory in 'init.S' is :
tlbentry( CFG_PCI_MEMBASE, SZ_256M, 0x00000000, 3, AC_R|AC_W|SA_G|SA_I )
 
The 'CFG_PCI_MEMBASE' is set to 0x80000000 in 'ocotea.h'.
 
 
My question is how to select the value for 'CFG_PCI_MEMBASE'. 
Can I use any value (say 0x50000000 ) provided it is not overlapping with other devices?
 
If we are using Board Memory Map as a reference then the 32-bit address 'CFG_PCI_MEMBASE'  used in 'telbentry' should have set to: 0x90000000
 
 
I am trying to find out the logic behind the selection of value for the variabale 'CFG_PCI_MEMBASE' in:
tlbentry( CFG_PCI_MEMBASE, SZ_256M, 0x00000000, 3, AC_R|AC_W|SA_G|SA_I )
 
Waiting for your reply.
 
 
Regards,
Sachin Rane
 
 
 

________________________________

From: u-boot-users-bounces@lists.sourceforge.net on behalf of Stefan Roese
Sent: Thu 6/12/2008 5:51 AM
To: u-boot-users at lists.sourceforge.net
Cc: Sachin Rane
Subject: Re: [U-Boot-Users] Value of CFG_PCI_MEMBASE



On Wednesday 11 June 2008, Sachin Rane wrote:
> In the 'include/configs/ocotea.h" file:
> 8<-------------------------------------------------------------------------
>----------------------------
>
> #define CFG_PCI_MEMBASE     0x80000000      /* mapped pci memory        */

This is the virtual address.

> 8<-------------------------------------------------------------------------
>----------------------------
>
> But the Memory map of the Ocotea board (PPC440GX? Evaluation Board User's
> Manual) has mentioned about the PCI memory  as: Start Address (32 Bit) -
> 9000 0000
> End Address (32 Bit) - 9FFF FFFF
> Start Address (36 Bit) - 3 0000 0000
> End Address (36 Bit) - 3 0FFF FFFF
> Size - 256MB 256 MB

The users manual referrs to the physical (36bit) address.

> I am not clear about the logic behind the value assigned to CFG_PCI_MEMBASE
>    i.e. 0x80000000

The mapping between virtual and physical address is done via the MMU. I
suggest you take a look at the init.S file in the board directory. This
should make it clear.

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

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[U-Boot-Users] Value of CFG_PCI_MEMBASE

[Stefan Roese]

On Monday 16 June 2008, Sachin Rane wrote:
> Infact I was looking for the info to create a proper 'tlbentry' in 'init.S'
> As per my understanding the 'tlbentry' is to map 32-bit address to 36-bit
> address.
>
> The 'tlbenry' for the PCI Memory in 'init.S' is :
> tlbentry( CFG_PCI_MEMBASE, SZ_256M, 0x00000000, 3, AC_R|AC_W|SA_G|SA_I )
>
> The 'CFG_PCI_MEMBASE' is set to 0x80000000 in 'ocotea.h'.
>
> My question is how to select the value for 'CFG_PCI_MEMBASE'.
> Can I use any value (say 0x50000000 ) provided it is not overlapping with
> other devices?

Yes. I suggest to start with 0x80000000 since this leaves the first 2 GB for 
SDRAM.

> If we are using Board Memory Map as a reference then the 32-bit address
> 'CFG_PCI_MEMBASE'  used in 'telbentry' should have set to: 0x90000000

Why is this? Which "Board Memory Map" are you referring to?

> I am trying to find out the logic behind the selection of value for the
> variabale 'CFG_PCI_MEMBASE' in: tlbentry( CFG_PCI_MEMBASE, SZ_256M,
> 0x00000000, 3, AC_R|AC_W|SA_G|SA_I )

Whats the problems with using 0x80000000 here?

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot-Users] Value of CFG_PCI_MEMBASE

[Sachin]

Hi Stefan,

I don't have much knowledge about how u-boot being implemented.

>Why is this? Which "Board Memory Map" are you referring to?

I am referring to 'Peripheral Registers' table given in 'PPC440GX? 
Evaluation Board User?s Manual'.
I found the 32 bit value passed to the 'telbentry' macro is matching 
with the values given in the '32 Bit Address' column of the table except 
for 'PCI Memory - cached'.
And this mismatch confused me.

 From your last reply I understood that it is the developer who got the 
freedom to decide the 32-bit value.
Is that correct?

Regards,
Sachin






Stefan Roese wrote:
> On Monday 16 June 2008, Sachin Rane wrote:
>   
>> Infact I was looking for the info to create a proper 'tlbentry' in 'init.S'
>> As per my understanding the 'tlbentry' is to map 32-bit address to 36-bit
>> address.
>>
>> The 'tlbenry' for the PCI Memory in 'init.S' is :
>> tlbentry( CFG_PCI_MEMBASE, SZ_256M, 0x00000000, 3, AC_R|AC_W|SA_G|SA_I )
>>
>> The 'CFG_PCI_MEMBASE' is set to 0x80000000 in 'ocotea.h'.
>>
>> My question is how to select the value for 'CFG_PCI_MEMBASE'.
>> Can I use any value (say 0x50000000 ) provided it is not overlapping with
>> other devices?
>>     
>
> Yes. I suggest to start with 0x80000000 since this leaves the first 2 GB for 
> SDRAM.
>
>   
>> If we are using Board Memory Map as a reference then the 32-bit address
>> 'CFG_PCI_MEMBASE'  used in 'telbentry' should have set to: 0x90000000
>>     
>
> Why is this? Which "Board Memory Map" are you referring to?
>
>   
>> I am trying to find out the logic behind the selection of value for the
>> variabale 'CFG_PCI_MEMBASE' in: tlbentry( CFG_PCI_MEMBASE, SZ_256M,
>> 0x00000000, 3, AC_R|AC_W|SA_G|SA_I )
>>     
>
> Whats the problems with using 0x80000000 here?
>
> Best regards,
> Stefan
>
> =====================================================================
> DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
> =====================================================================
>
>
>   

[U-Boot-Users] Value of CFG_PCI_MEMBASE

[Stefan Roese]

Hi Sachin,

On Monday 16 June 2008, Sachin Rane, Alphion Communications wrote:
> I don't have much knowledge about how u-boot being implemented.
>
> >Why is this? Which "Board Memory Map" are you referring to?
>
> I am referring to 'Peripheral Registers' table given in 'PPC440GX?
> Evaluation Board User?s Manual'.
> I found the 32 bit value passed to the 'telbentry' macro is matching
> with the values given in the '32 Bit Address' column of the table except
> for 'PCI Memory - cached'.
> And this mismatch confused me.
>
>  From your last reply I understood that it is the developer who got the
> freedom to decide the 32-bit value.
> Is that correct?

Yes. You have some freedom in this assignment of the 32-bit virtual addresses. 
Overlapping is not allowed of course.

Best regards,
Stefan

=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot-Users] Value of CFG_PCI_MEMBASE

[Sachin]

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[U-Boot-Users] Value of CFG_PCI_MEMBASE

[Sachin]

Hi,
In the 'include/configs/ocotea.h" file:
8<-----------------------------------------------------------------------------------------------------
#define CFG_PCI_MEMBASE 0x80000000 /* mapped pci memory */
8<-----------------------------------------------------------------------------------------------------
But the Memory map of the Ocotea board (PPC440GX? Evaluation Board 
User?s Manual) has mentioned about the PCI memory as:
Start Address (32 Bit) - 9000 0000
End Address (32 Bit) - 9FFF FFFF
Start Address (36 Bit) - 3 0000 0000
End Address (36 Bit) - 3 0FFF FFFF
Size - 256MB 256 MB
I am not clear about the logic behind the value assigned to 
CFG_PCI_MEMBASE i.e. 0x80000000
Can you help me to figure it out?
Regards,
Sachin Rane