On Thu, Aug 04, 2016 at 04:32:57PM +0200, Geert Uytterhoeven wrote: > Hi Rich, > > On Thu, Aug 4, 2016 at 6:30 AM, Rich Felker <dalias@xxxxxxxx> wrote: > > --- /dev/null > > +++ b/drivers/irqchip/irq-jcore-aic.c > > > +int __init aic_irq_of_init(struct device_node *node, struct device_node *parent) > > +{ > > + unsigned min_irq = JCORE_AIC2_MIN_HWIRQ; > > + unsigned dom_sz = JCORE_AIC_MAX_HWIRQ+1; > > + struct irq_domain *domain; > > + > > + pr_info("Initializing J-Core AIC\n"); > > + > > + /* AIC1 needs priority initialization to receive interrupts. */ > > + if (of_device_is_compatible(node, "jcore,aic1")) { > > + unsigned cpu; > > + > > + for_each_present_cpu(cpu) { > > + void __iomem *base = of_iomap(node, cpu); > > Just double checking, these regions are per-cpu hardware registers, > and not related to other functionality at all? > > I.e. when booting on an SMP-capable system a kernel compiled with > CONFIG_SMP=n, or using the kernel command line option maxcpus= > to reduce the number of CPUs, no ill effects happen by not mapping the > region and not writing to the register below? If you're not using a secondary cpu, there's no harm in ignoring its aic completely. Rich -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html