[ECOS] MPC860 and IMMR location

[ECOS] MPC860 and IMMR location

[Barton Meeks]

As I stared writing this, I was thinking there was a
problem with the viper HAL, but it may just be a
matter of me being confused by the comments.  In the
code below, I believe 0xff000000 is indeed the MCP
registers for just a brief period, until viper.S gets
going.  Then the internal memory is moved to
0xfa020000, which is listed in the comments below as
"Control/Status+LEDs."

This is from viper/current/src/hal_aux.c:

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
};




Background information:

At reset time, the 860 family has a configuration (via
device pins) as to the location of the internal memory
space. This controls the initialization of the IMMR
register, which can be later changed by software.

This setting of the IMMR is changed by ecos based on
the setting here:

mpc8xx/current/include/var_regs.h:
    #define CYGARC_REG_IMM_BASE 0xfa200000

I'm guessing that the initial (at reset) value doesn't
really matter, since the value listed above is written
to the IMMR first thing in hal_hardware_init (such as
in the files mbx.S or viper.S.)

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Re: [ECOS] MPC860 and IMMR location

[Gary Thomas]

On Thu, 2002-07-18 at 09:54, Barton Meeks wrote:
> As I stared writing this, I was thinking there was a
> problem with the viper HAL, but it may just be a
> matter of me being confused by the comments.  In the
> code below, I believe 0xff000000 is indeed the MCP
> registers for just a brief period, until viper.S gets
> going.  Then the internal memory is moved to
> 0xfa020000, which is listed in the comments below as
> "Control/Status+LEDs."
> 

The comments are stale, sorry.  In fact, I don't think the
0xFF000000 space is used anymore at all.

The MCP registers were moved to 0xFA020000 to be more compatible
with the Motorola MBX series of boards.

> This is from viper/current/src/hal_aux.c:
> 
> 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
> };
> 
> 
> 
> 
> Background information:
> 
> At reset time, the 860 family has a configuration (via
> device pins) as to the location of the internal memory
> space. This controls the initialization of the IMMR
> register, which can be later changed by software.
> 
> This setting of the IMMR is changed by ecos based on
> the setting here:
> 
> mpc8xx/current/include/var_regs.h:
>     #define CYGARC_REG_IMM_BASE 0xfa200000
> 
> I'm guessing that the initial (at reset) value doesn't
> really matter, since the value listed above is written
> to the IMMR first thing in hal_hardware_init (such as
> in the files mbx.S or viper.S.)
> 
> __________________________________________________
> Do You Yahoo!?
> Yahoo! Autos - Get free new car price quotes
> http://autos.yahoo.com
> 
> -- 
> Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
> and search the list archive: http://sources.redhat.com/ml/ecos-discuss



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