Re: [PATCH 4/10] Add arch/powerpc driver for UIC, PPC4xx interrupt controller

[Josh Boyer <jwboyer@linux.vnet.ibm.com>]

On Thu, 2007-03-22 at 20:22 +1100, David Gibson wrote:
> 
> Index: working-2.6/arch/powerpc/sysdev/uic.c
> ===================================================================

 <snip>

> +static struct uic * __init uic_init_one(struct device_node *node)
> +{
> +	struct uic *uic;
> +	const u32 *indexp, *dcrreg;
> +	int len;
> +
> +	BUG_ON(! device_is_compatible(node, "ibm,uic"));
> +
> +	uic = alloc_bootmem(sizeof(*uic));
> +	if (! uic)
> +		return NULL; /* FIXME: panic? */
> +
> +	memset(uic, 0, sizeof(*uic));
> +	uic->of_node = of_node_get(node);
> +	indexp = get_property(node, "cell-index", &len);
> +	if (!indexp || (len != sizeof(u32))) {
> +		printk(KERN_ERR "uic: Device node %s has missing or invalid "
> +		       "cell-index property\n", node->full_name);
> +		return NULL;
> +	}
> +	uic->index = *indexp;
> +
> +	dcrreg = get_property(node, "dcr-reg", &len);
> +	if (!dcrreg || (len != 2*sizeof(u32))) {
> +		printk(KERN_ERR "uic: Device node %s has missing or invalid "
> +		       "dcr-reg property\n", node->full_name);
> +		return NULL;
> +	}
> +	uic->dcrbase = *dcrreg;
> +
> +	uic->irqhost = irq_alloc_host(IRQ_HOST_MAP_LINEAR, NR_UIC_INTS,
> +				      &uic_host_ops, -1);
> +	if (! uic->irqhost) {
> +		of_node_put(node);
> +		return NULL; /* FIXME: panic? */
> +	}
> +
> +	uic->irqhost->host_data = uic;
> +
> +	/* Start with all interrupts disable and non-critical */
> +	mtdcr(uic->dcrbase + UIC_ER, 0);
> +	mtdcr(uic->dcrbase + UIC_CR, 0);

I think at this point we should also clear the interrupts in the SR
register as well.  When playing with the Bamboo port, I found that the
firmware leaves pending interrupts, which can lead to some not nice
results when the cascade bits are enabled.

josh