[U-Boot-Users] question about interrupt

loody miloody at gmail.com
Tue May 20 07:53:00 CEST 2008


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

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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