On Wed, 7 Nov 2012, Vineet Gupta wrote:

+void __init init_IRQ(void)
+{
+	const int irq = TIMER0_IRQ;
+
+	/*
+	 * Each CPU needs to register irq of it's private TIMER0.
+	 * The APIs request_percpu_irq()/enable_percpu_irq() will not be
+	 * functional, if we don't "prep" the generic IRQ sub-system with
+	 * the following:
+	 * -Ensure that devid passed to request_percpu_irq() is indeed per cpu
+	 * -disable NOAUTOEN, w/o which the device handler never gets called

What sets NOAUTOEN in the first place? The core code definitely does
not.

+	 */
+	irq_set_percpu_devid(irq);
+	irq_modify_status(irq, IRQ_NOAUTOEN, 0);

Aside of that we have irq_clear_status_flags() for this.

+	plat_init_IRQ();
+}

+int __init get_hw_config_num_irq(void)

How is that function used ?

+{
+	uint32_t val = read_aux_reg(ARC_REG_VECBASE_BCR);
+
+	switch (val & 0x03) {
+	case 0:
+		return 16;
+	case 1:
+		return 32;
+	case 2:
+		return 8;
+	default:
+		return 0;
+	}
+
+	return 0;
+}

Thanks,

	tglx