[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 at 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

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