[ECOS] One urgent questions regarding to MMU, help wanted!

[ECOS] One urgent questions regarding to MMU, help wanted!

[Ling Su]

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Hello, 
 
I have one specific question on MMU in eCos. My understanding is currently 
in eCos there is no MMU support, so is there any concept of "Virtual memory 
address"? Actually my question comes from the PCI memory space allocation, is 
there any diference between the CPU seeing address and base_register setting for 
the PCI bus? Thanks for any hints!
 
Best Regards,
-Ling
 

Re: [ECOS] One urgent questions regarding to MMU, help wanted!

[Jonathan Larmour]

> Ling Su wrote:
> 
> Hello,
> 
> I have one specific question on MMU in eCos. My understanding is
> currently in eCos there is no MMU support, so is there any concept of
> "Virtual memory address"? Actually my question comes from the PCI memory
> space allocation, is there any diference between the CPU seeing address
> and base_register setting for the PCI bus? Thanks for any hints!

Look in <cyg/hal/plf_io.h>. For the vrc4373, you will see:

// This is where the PCI spaces are mapped in the CPU's (virtual)
// address space.
#define HAL_PCI_PHYSICAL_MEMORY_BASE    0xC0000000
#define HAL_PCI_PHYSICAL_IO_BASE        0xAC000000

And in the PCI library, in pci.c, when I/O or memory resources are
allocated, each memory/io region is just allocated sequentially on top of
the above addresses. I believe :-).

Jifl
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