Re: interrupt handler in blob

[Erik M. <J.A...@it...>]

On Thu, Apr 25, 2002 at 12:33:34PM +0200, Abraham vd Merwe wrote:
> I'm beating my head against a stone here :P
> 
> If I set the irq exception handler to any address in a
> INIT_LEVEL_DRIVER_SELECTION hook and I check that address later on in a
> INIT_LEVEL_OTHER_STUFF hook, the address differs, e.g. with
> 
> static void frodo_set_irq()
> {
>    u32 *irq_vector = (u32 *) 0x00000018;
>    *irq_vector = 0xdeadbeaf;   

You're trying to write to flash...

> }
> __initlist(frodo_set_irq,INIT_LEVEL_DRIVER_SELECTION);
> 
> static void frodo_debug_irq()
> {
>    u32 *irq_vector = (u32 *) 0x00000018;
>    printf ("*irq_vector == 0x%.8x\n",*irq_vector);   
> }
> __initlist(frodo_debug_irq,INIT_LEVEL_OTHER_STUFF);
> 
> I get *irq_vector == 0xea0000c1 when booting blob.
> 
> I can't see anything in the second stage boot loader that modifies this
> address, so what is happening here?

Writing to flash doesn't work. Do it like I suggested before: "irq" in
start-sa11x0.S has to become an indirect branch to an entry point in
trampoline.S. The entry point in trampoline.S on its turn can push some
registers on the stack and branch&link into the C irq handler.


Erik

-- 
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Faculty
of Information Technology and Systems, Delft University of Technology,
PO BOX 5031, 2600 GA Delft, The Netherlands  Phone: +31-15-2783635
Fax: +31-15-2781843  Email: J.A...@it...
WWW: http://www-ict.its.tudelft.nl/~erik/