Re: [PATCH v4 2/2] irqchip: add J-Core AIC driver

Mark Rutland
2016-07-27T10:12:46Z

On Wed, Jul 27, 2016 at 05:35:09AM +0000, Rich Felker wrote:
> +int __init aic_irq_of_init(struct device_node *node, struct device_node *parent)
> +{
> + struct aic_data *aic = &aic_data;
> + unsigned min_irq = 64;
> +
> + pr_info("Initializing J-Core AIC\n");
> +
> + if (!of_device_is_compatible(node, "jcore,aic2")) {
> + unsigned cpu;
> + for_each_possible_cpu(cpu) {
> + void __iomem *base = of_iomap(node, cpu);
> + if (!base)
> + continue;

This sounds like it would be a critical error.

It would be best to at least pr_warn() if you can't map a CPU's AI
interface.

> + pr_info("Local AIC1 enable for cpu %u at %p\n",
> + cpu, base + AIC1_INTPRI);
> + __raw_writel(0xffffffff, base + AIC1_INTPRI);
> + }

Here base goes out of scope. If you don't need it, it would be best
practice to iounmap it (even if that happens to be a no-op on your
arch).

> + min_irq = 16;
> + }
> +
> + aic->chip.name = node->name;

It's probably best to give the name explicitly in the driver (e.g.
"AIC"), rather than taknig whatever happens to be in the DT (which
should be 'interrupt-controller@<addr>'.

> + aic->chip.irq_mask = noop;
> + aic->chip.irq_unmask = noop;

If the core code wants to mask IRQs, how do you handle that? Can you
mask your CPU traps?

Thanks,
Mark.