[U-Boot-Users] question about interrupt

[Chetan Nanda]

On Tue, May 20, 2008 at 11:23 AM, loody <miloody at gmail.com> wrote:
> hi:
> thanks for your kind help.
> As far as I know, the cpu will set the PC to irq/fiq vector when the
> these exceptions are triggered. And these pointers are usually at the
> beginning position of bootloader, if bootloader wants to pass these
> functions to kernel, there may be some instructions like "b xxxxxx'.
>
> If uboot don't handle these exceptions, how the kernel knows these events?
> appreciate your kind help,
> miloody
>
as i have mentioned, u-boot do not handle any interrupt, and neither
it pass vector information to OS it going to boot.
But OS that booted specify its own vector tables for handling the
interrupts and exception.

Anyone, correct me if i am at wrong path.


> 2008/5/20 Chetan Nanda <chetannanda at gmail.com>:
>> On Tue, May 20, 2008 at 7:41 AM, loody <miloody at gmail.com> wrote:
>>> Dear all:
>>> I have trace interrupt/Fiq vector in uboot based on smdk2410.
>>> after we save user registers, we jump to following functions I
>>> excerpted at the end of mail.
>>> But these 2 functions seems not really handle the irq/fiq, would
>>> someone please tell me where the real
>>> interrupt handler is?
>>>
>>> Is the interrupt handled in kernel?
>>> if it really is, how loader pass the vector pointer to OS?
>>> appreciate your help,
>>> miloody
>>>
>>>
>>> void do_fiq (struct pt_regs *pt_regs)
>>> {
>>>        printf ("fast interrupt request\n");
>>>        show_regs (pt_regs);
>>>        bad_mode ();
>>> }
>>>
>>> void do_irq (struct pt_regs *pt_regs)
>>> {
>>> #if defined (CONFIG_USE_IRQ) && defined (CONFIG_ARCH_INTEGRATOR)
>>>        /* ASSUMED to be a timer interrupt  */
>>>        /* Just clear it - count handled in */
>>>        /* integratorap.c                   */
>>>        *(volatile ulong *)(CFG_TIMERBASE + 0x0C) = 0;
>>> #else
>>>        printf ("interrupt request\n");
>>>        show_regs (pt_regs);
>>>        bad_mode ();
>>> #endif
>>> }
>>>
>> As far as i know, U-Boot do no support interrupts, and above functions
>> are just the place holders.
>> and also Interrupts for various devices are generally not enabled in
>> u-boot code.
>>
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>