Re: Serial related oops

["Michael K. Edwards" <medwards.linux@gmail.com>]

Russell, thanks again for offering to look at this; the more oopses
and soft lockups I see on this board, the more I think you're right
and we have an IRQ handling race.

Here's the struct irqchip setup:

/* mask irq, refer ssection 2.6 under chip 8618 document */
static void mv88w8xx8_mask_irq(unsigned int irq)
{
        MV88W8XX8_REG_WRITE(MV88W8XX8_INT_ENABLE_CLR,(1 << irq));
}

/* unmask irq, refer ssection 2.6 under chip 8618 document */
static void mv88w8xx8_unmask_irq(unsigned int irq)
{
        MV88W8XX8_REG_WRITE(MV88W8XX8_INT_ENABLE_SET,(1 << irq));
}

/* ack to CPU interrupts and also individual timer interrupts */
static void mv88w8xx8_mask_ack_irq(unsigned int irq)
{
        mv88w8xx8_mask_irq(irq);

        if (irq < IRQ_TIMER1 || irq > IRQ_TIMER4) return;

        /* write 0 to clear interrupt and  re-enable further interrupts */
        MV88W8XX8_REG_WRITE(MV88W8XX8_TIMER_INT_SOURCE, ~(1<<(irq-4)));
}

static struct irqchip mv88w8xx8_chip = {
        .ack    = mv88w8xx8_mask_ack_irq,
        .mask   = mv88w8xx8_mask_irq,
        .unmask = mv88w8xx8_unmask_irq,
};

/**
 * called by core.c to  initialize the IRQ module
 */
void mv88w8xx8_init_irq(void)
{
        int irq;

        for (irq = 0; irq < NR_IRQS; irq++) {
                set_irq_chip(irq, &mv88w8xx8_chip);
                set_irq_handler(irq, do_level_IRQ);
                set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
        }
}