On Friday, July 15, 2016 1:15:58 PM CEST Wan Zongshun wrote: > > Actually, I have two choice to implement this function: > > option1: > > void __exception_irq_entry aic_handle_irq(struct pt_regs *regs) > { > u32 hwirq; > > (void)readl(aic_base + REG_AIC_IPER); > hwirq = readl(aic_base + REG_AIC_ISNR); > > handle_IRQ((irq_find_mapping(aic_domain, hwirq)), regs); > } (side note: I think you want handle_domain_irq()) > option2: > > void __exception_irq_entry aic_handle_irq(struct pt_regs *regs) > { > u32 hwirq; > > hwirq = readl(aic_base + REG_AIC_IPER); > hwirq <<= 2; > > handle_IRQ((irq_find_mapping(aic_domain, hwirq)), regs); > } > > Though the option2 do shift for hwirq, but it seems better than do io > operation by readl,so I prefer to option2, agree? That will only return an irq number that is a multiple of four, which seems wrong since the numbers are not that. Did you mean to write hwirq = ilog2(hwirq); ? That assumes that REG_AIC_IPER contains a 32-bit value with one single bit set to indicate which IRQ was triggered. If the difference is only in performance, you could try measuring which of the two ends up being faster. Arnd -- 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