[ECOS] Re: Regd. the MMU in eCos1.3.1

Prabal Halder prabal@cdotd.ernet.in
Thu Apr 3 12:36:00 GMT 2003


Thanks for your kind information.

I have new query. 

 In eCos, is there any support to lock a range of memory address and also
assign protection for that region?

  If the support does exist, please tell me how to do it.


Regards,
Prabal
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On Thu, 3 Apr 2003, Andrew Lunn wrote:

> Please remember to send to eCos discuss and not the individuals.
> 
> On Thu, Apr 03, 2003 at 03:08:12PM +0500, Prabal Halder wrote:
> > 
> >  We are using eCos1.3.1 in our project. We have been facing problem
> > with MMU.
> 
> 1.3.1 is long dead. I don't have it installed any more. The files i
> refer to be low are from anoncvs. 
> 
> >      According to my understanding, the cyg_hal_mem_map[] array is used to
> > store the memory mapping. Which will be stored in the I & D Cache 
> > (in TLB) in the following function.
> [..]
> 
> >     In cyg_hal_map_memory(...) call we are passing the virtual address,
> > physical address, flags & size of the structure "cyg_hal_mem_map[]". But
> > in the ecos source code, I have not found the initialization of this
> > structure.
> > 
> >     Please tell me, which is the place to initialize this structure and
> > how to do it.
> 
> 
> hal/powerpc/arch/current/include/hal_mem.h:107
> 
> #define CYGARC_MEMDESC_TABLE          cyg_memdesc_t cyg_hal_mem_map[]
> 
> ./powerpc/viper/current/src/hal_aux.c:64
> 
> // The memory map is weakly defined, allowing the application to redefine
> // it if necessary. The regions defined below are the minimum requirements.
> CYGARC_MEMDESC_TABLE CYGBLD_ATTRIB_WEAK = {
>     // Mapping for the Viper 855/860 development boards
>     CYGARC_MEMDESC_CACHE(   0xfe000000, 0x00800000 ), // ROM region
>     CYGARC_MEMDESC_NOCACHE( 0xff000000, 0x00100000 ), // MCP registers
>     CYGARC_MEMDESC_NOCACHE( 0xfa000000, 0x00400000 ), // Control/Status+LEDs
>     CYGARC_MEMDESC_CACHE(   CYGMEM_REGION_ram, CYGMEM_REGION_ram_SIZE ), // Main
>  memory
>  
>     CYGARC_MEMDESC_TABLE_END
> };
> 
> Something similar exists for all PPC HALS.
> 
>           Andrew
> 
> 



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