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Re: One urgent questions regarding to MMU, help wanted!
- To: Ling Su <lingsu at palmmicro dot com>
- Subject: Re: [ECOS] One urgent questions regarding to MMU, help wanted!
- From: Jonathan Larmour <jlarmour at redhat dot com>
- Date: Mon, 11 Sep 2000 03:40:54 +0100
- CC: ecos-discuss at sources dot redhat dot com
- Organization: Red Hat UK Ltd.
- References: <000b01c019ba$c816e910$1201a8c0@crusoe>
> 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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