[okl4-developer] Physical Memory & Virtual Memory

[Gabi Voiculescu]

Hi.

I can answer the first part.

In your SoCxxx/tools/machines.py you should have the following line for all your platforms (clases):
memory['physical'] = [Region(0x80000000L, 0xA0000000L)]

I personally do not have an explicit memory['virtual'] entry for my platforms.

If I remember correctly, okl4 usually builds in virtual memory the kernel starting at the base 0xf000.0000, with io sfr's mapped starting from 0xf900.0000. I think memory virtual can influence the kernel's base virtual address but I'm not sure. 

Good luck,
Gabi Voiculescu

 


--- On Tue, 9/15/09, Kumar Sanghvi <divinekumar at gmail.com> wrote:

From: Kumar Sanghvi <divinekumar at gmail.com>
Subject: [okl4-developer] Physical Memory & Virtual Memory
To: developer at okl4.org
Date: Tuesday, September 15, 2009, 6:19 AM

Hi All,

I have some very basic / fundamental (may even sound silly) questions:-

How do we determine the values for the following variables in the platform/SoCXX/tools/machines.py file:-

1) memory[physical]  .. This value I believe corresponds to RAM (silly question) and probably can be obtained by consulting the TRM of SoCXX. But still, any advise would be helpful.

2) memory[virtual] ... how this value is determined for any particular SoCXX?
3) base_vaddr ... again here, how this value is determined for any particular SoCXX?

4) Based on above values, final memory layout will be reflected in the image.elf file generated. But any basic explanation related to this would be helpful.

5) Also, based on above values, the parameters that we pass to u-boot will also change.

For e.g. consider that an SoCXX has 512MB RAM with address range as : 0x8000 0000 - 0x9FFF FFFF
How do we determine the values of above variables based on this information?


Thanks to all,
Kumar.




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