[mc1322x] _rom_data_init_ branch

[Giandomenico Rossi]

> I can't say for sure exactly what rom_data_init does --- unfortunatly
> only Freescale has the answer to that. 
> 
> The following:
> 
>    .org 0x120
>    ROM_var_start: .word 0
>    .org 0x7ff
>    ROM_var_end:   .word 0
> 
> reserves space for the ROM services and I believe rom_data_init does
> work in this area.
I report, if it could be useful to someone,  some developments on my
hacking rom_data_init call.

I have just notice that in rom_data_init call there are 2 entries at
address 0x11788 and 11798 of the form :
+-----------------------------------------------------+
|   address1 |  address2  | size  | function adddress |
+-----------------------------------------------------+
|  0x40020c  |  0x40020c  | 0x520 |    0x10b2c        |
+-----------------------------------------------------+
|  0x400120  |  0x400120  | 0x97  |    0x10a9c        |
+-----------------------------------------------------+
The first routine to 0x10b2c set to 0  memory 
from 0x40020c to 0x40020c+0x520 but I don't know what stand for.

The second entry point refers to address 0x400120 which is ROM_var_start
as  Mariano said!

Well, I was writing code for CRM interrupt handler when I figured out
that I didn't know where Interrupt handler table was located.
Looking inside the file doc/ws-dis of mc1322x-tests it's easy to find in
the exception vector table the address of irqHandler that is the routine
where CPU jumps whenever a normal interrupt request is fired:

  400018:       eaf041fc        b       10810 <IrqHandler>


IrqHadler is at address 0x10810.
This is a routine coded in ARM instructions  so I had no problem
disassembling it with FORTH DASM and discover that it does the
following:

i)  read pending normal interrupt source from read-only register
NIVECTOR

ii)  check if source is less than 11, the max number of interrupt
sources 

iii) if it is the case load an address from 0x10838+8 in R1

iv) add 4*( interrupt source ) to R1 and jumps there.

The very funny thing is that looking for address in 0x10838+8 I've found
0x400120 which is ROM_var_start !!!! EUREKA!!!!
** First 11*4 bytes of ROM_var_start contain interrupt vector table. ** 

Rom Driver has 2 obscure functions for handler interrupts which are:

ITC_Init ()          @ 0xfe9d
IntAssignHandler ()  @ 0xff25

The latter resets interrupt vector table and the former inserts an
handler to interrupt table.
Rom_data_init uses ITC_Init to fill interrupt vector table with the
address of a dummy function located in rom at address 0x1001D .
Call to  IntAssignHandler add handler function address to a
corresponding  interrupt  vector table at ROM_var_start.