arch/mips/lantiq/irq.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  *
  * Copyright (C) 2010 John Crispin <john@phrozen.org>
  * Copyright (C) 2010 Thomas Langer <thomas.langer@lantiq.com>
  */

 #include <linux/interrupt.h>
 #include <linux/ioport.h>
 #include <linux/sched.h>
 #include <linux/irqchip.h>
 #include <linux/irqdomain.h>
 #include <linux/of_platform.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>

 #include <asm/bootinfo.h>
 #include <asm/irq_cpu.h>

 #include <lantiq_soc.h>
 #include <irq.h>

 /* register definitions - internal irqs */
 #define LTQ_ICU_ISR		0x0000
 #define LTQ_ICU_IER		0x0008
 #define LTQ_ICU_IOSR		0x0010
 #define LTQ_ICU_IRSR		0x0018
 #define LTQ_ICU_IMR		0x0020

 #define LTQ_ICU_IM_SIZE		0x28

 /* register definitions - external irqs */
 #define LTQ_EIU_EXIN_C		0x0000
 #define LTQ_EIU_EXIN_INIC	0x0004
 #define LTQ_EIU_EXIN_INC	0x0008
 #define LTQ_EIU_EXIN_INEN	0x000C

 /* number of external interrupts */
 #define MAX_EIU			6

 /* the performance counter */
 #define LTQ_PERF_IRQ		(INT_NUM_IM4_IRL0 + 31)

 /*
  * irqs generated by devices attached to the EBU need to be acked in
  * a special manner
  */
 #define LTQ_ICU_EBU_IRQ		22

 #define ltq_icu_w32(vpe, m, x, y)	\
 	ltq_w32((x), ltq_icu_membase[vpe] + m*LTQ_ICU_IM_SIZE + (y))

 #define ltq_icu_r32(vpe, m, x)		\
 	ltq_r32(ltq_icu_membase[vpe] + m*LTQ_ICU_IM_SIZE + (x))

 #define ltq_eiu_w32(x, y)	ltq_w32((x), ltq_eiu_membase + (y))
 #define ltq_eiu_r32(x)		ltq_r32(ltq_eiu_membase + (x))

 /* we have a cascade of 8 irqs */
 #define MIPS_CPU_IRQ_CASCADE		8

 static int exin_avail;
 static u32 ltq_eiu_irq[MAX_EIU];
 static void __iomem *ltq_icu_membase[NR_CPUS];
 static void __iomem *ltq_eiu_membase;
 static struct irq_domain *ltq_domain;
 static DEFINE_SPINLOCK(ltq_eiu_lock);
 static DEFINE_RAW_SPINLOCK(ltq_icu_lock);
 static int ltq_perfcount_irq;

 int ltq_eiu_get_irq(int exin)
 {
 	if (exin < exin_avail)
 		return ltq_eiu_irq[exin];
 	return -1;
 }

 void ltq_disable_irq(struct irq_data *d)
 {
 	unsigned long offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
 	unsigned long im = offset / INT_NUM_IM_OFFSET;
 	unsigned long flags;
 	int vpe;

 	offset %= INT_NUM_IM_OFFSET;

 	raw_spin_lock_irqsave(&ltq_icu_lock, flags);
 	for_each_present_cpu(vpe) {
 		ltq_icu_w32(vpe, im,
 			    ltq_icu_r32(vpe, im, LTQ_ICU_IER) & ~BIT(offset),
 			    LTQ_ICU_IER);
 	}
 	raw_spin_unlock_irqrestore(&ltq_icu_lock, flags);
 }

 void ltq_mask_and_ack_irq(struct irq_data *d)
 {
 	unsigned long offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
 	unsigned long im = offset / INT_NUM_IM_OFFSET;
 	unsigned long flags;
 	int vpe;

 	offset %= INT_NUM_IM_OFFSET;

 	raw_spin_lock_irqsave(&ltq_icu_lock, flags);
 	for_each_present_cpu(vpe) {
 		ltq_icu_w32(vpe, im,
 			    ltq_icu_r32(vpe, im, LTQ_ICU_IER) & ~BIT(offset),
 			    LTQ_ICU_IER);
 		ltq_icu_w32(vpe, im, BIT(offset), LTQ_ICU_ISR);
 	}
 	raw_spin_unlock_irqrestore(&ltq_icu_lock, flags);
 }

 static void ltq_ack_irq(struct irq_data *d)
 {
 	unsigned long offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
 	unsigned long im = offset / INT_NUM_IM_OFFSET;
 	unsigned long flags;
 	int vpe;

 	offset %= INT_NUM_IM_OFFSET;

 	raw_spin_lock_irqsave(&ltq_icu_lock, flags);
 	for_each_present_cpu(vpe) {
 		ltq_icu_w32(vpe, im, BIT(offset), LTQ_ICU_ISR);
 	}
 	raw_spin_unlock_irqrestore(&ltq_icu_lock, flags);
 }

 void ltq_enable_irq(struct irq_data *d)
 {
 	unsigned long offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
 	unsigned long im = offset / INT_NUM_IM_OFFSET;
 	unsigned long flags;
 	int vpe;

 	offset %= INT_NUM_IM_OFFSET;

 	vpe = cpumask_first(irq_data_get_effective_affinity_mask(d));

 	/* This shouldn't be even possible, maybe during CPU hotplug spam */
 	if (unlikely(vpe >= nr_cpu_ids))
 		vpe = smp_processor_id();

 	raw_spin_lock_irqsave(&ltq_icu_lock, flags);

 	ltq_icu_w32(vpe, im, ltq_icu_r32(vpe, im, LTQ_ICU_IER) | BIT(offset),
 		    LTQ_ICU_IER);

 	raw_spin_unlock_irqrestore(&ltq_icu_lock, flags);
 }

 static int ltq_eiu_settype(struct irq_data *d, unsigned int type)
 {
 	int i;
 	unsigned long flags;

 	for (i = 0; i < exin_avail; i++) {
 		if (d->hwirq == ltq_eiu_irq[i]) {
 			int val = 0;
 			int edge = 0;

 			switch (type) {
 			case IRQF_TRIGGER_NONE:
 				break;
 			case IRQF_TRIGGER_RISING:
 				val = 1;
 				edge = 1;
 				break;
 			case IRQF_TRIGGER_FALLING:
 				val = 2;
 				edge = 1;
 				break;
 			case IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING:
 				val = 3;
 				edge = 1;
 				break;
 			case IRQF_TRIGGER_HIGH:
 				val = 5;
 				break;
 			case IRQF_TRIGGER_LOW:
 				val = 6;
 				break;
 			default:
 				pr_err("invalid type %d for irq %ld\n",
 					type, d->hwirq);
 				return -EINVAL;
 			}

 			if (edge)
 				irq_set_handler(d->hwirq, handle_edge_irq);

 			spin_lock_irqsave(&ltq_eiu_lock, flags);
 			ltq_eiu_w32((ltq_eiu_r32(LTQ_EIU_EXIN_C) &
 				    (~(7 << (i * 4)))) | (val << (i * 4)),
 				    LTQ_EIU_EXIN_C);
 			spin_unlock_irqrestore(&ltq_eiu_lock, flags);
 		}
 	}

 	return 0;
 }

 static unsigned int ltq_startup_eiu_irq(struct irq_data *d)
 {
 	int i;

 	ltq_enable_irq(d);
 	for (i = 0; i < exin_avail; i++) {
 		if (d->hwirq == ltq_eiu_irq[i]) {
 			/* by default we are low level triggered */
 			ltq_eiu_settype(d, IRQF_TRIGGER_LOW);
 			/* clear all pending */
 			ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INC) & ~BIT(i),
 				LTQ_EIU_EXIN_INC);
 			/* enable */
 			ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INEN) | BIT(i),
 				LTQ_EIU_EXIN_INEN);
 			break;
 		}
 	}

 	return 0;
 }

 static void ltq_shutdown_eiu_irq(struct irq_data *d)
 {
 	int i;

 	ltq_disable_irq(d);
 	for (i = 0; i < exin_avail; i++) {
 		if (d->hwirq == ltq_eiu_irq[i]) {
 			/* disable */
 			ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INEN) & ~BIT(i),
 				LTQ_EIU_EXIN_INEN);
 			break;
 		}
 	}
 }

 #if defined(CONFIG_SMP)
 static int ltq_icu_irq_set_affinity(struct irq_data *d,
 				    const struct cpumask *cpumask, bool force)
 {
 	struct cpumask tmask;

 	if (!cpumask_and(&tmask, cpumask, cpu_online_mask))
 		return -EINVAL;

 	irq_data_update_effective_affinity(d, &tmask);

 	return IRQ_SET_MASK_OK;
 }
 #endif

 static struct irq_chip ltq_irq_type = {
 	.name = "icu",
 	.irq_enable = ltq_enable_irq,
 	.irq_disable = ltq_disable_irq,
 	.irq_unmask = ltq_enable_irq,
 	.irq_ack = ltq_ack_irq,
 	.irq_mask = ltq_disable_irq,
 	.irq_mask_ack = ltq_mask_and_ack_irq,
 #if defined(CONFIG_SMP)
 	.irq_set_affinity = ltq_icu_irq_set_affinity,
 #endif
 };

 static struct irq_chip ltq_eiu_type = {
 	.name = "eiu",
 	.irq_startup = ltq_startup_eiu_irq,
 	.irq_shutdown = ltq_shutdown_eiu_irq,
 	.irq_enable = ltq_enable_irq,
 	.irq_disable = ltq_disable_irq,
 	.irq_unmask = ltq_enable_irq,
 	.irq_ack = ltq_ack_irq,
 	.irq_mask = ltq_disable_irq,
 	.irq_mask_ack = ltq_mask_and_ack_irq,
 	.irq_set_type = ltq_eiu_settype,
 #if defined(CONFIG_SMP)
 	.irq_set_affinity = ltq_icu_irq_set_affinity,
 #endif
 };

 static void ltq_hw_irq_handler(struct irq_desc *desc)
 {
 	unsigned int module = irq_desc_get_irq(desc) - 2;
 	u32 irq;
 	irq_hw_number_t hwirq;
 	int vpe = smp_processor_id();

 	irq = ltq_icu_r32(vpe, module, LTQ_ICU_IOSR);
 	if (irq == 0)
 		return;

 	/*
 	 * silicon bug causes only the msb set to 1 to be valid. all
 	 * other bits might be bogus
 	 */
 	irq = __fls(irq);
 	hwirq = irq + MIPS_CPU_IRQ_CASCADE + (INT_NUM_IM_OFFSET * module);
 	generic_handle_domain_irq(ltq_domain, hwirq);

 	/* if this is a EBU irq, we need to ack it or get a deadlock */
 	if (irq == LTQ_ICU_EBU_IRQ && !module && LTQ_EBU_PCC_ISTAT != 0)
 		ltq_ebu_w32(ltq_ebu_r32(LTQ_EBU_PCC_ISTAT) | 0x10,
 			LTQ_EBU_PCC_ISTAT);
 }

 static int icu_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
 {
 	struct irq_chip *chip = &ltq_irq_type;
 	struct irq_data *data;
 	int i;

 	if (hw < MIPS_CPU_IRQ_CASCADE)
 		return 0;

 	for (i = 0; i < exin_avail; i++)
 		if (hw == ltq_eiu_irq[i])
 			chip = &ltq_eiu_type;

 	data = irq_get_irq_data(irq);

 	irq_data_update_effective_affinity(data, cpumask_of(0));

 	irq_set_chip_and_handler(irq, chip, handle_level_irq);

 	return 0;
 }

 static const struct irq_domain_ops irq_domain_ops = {
 	.xlate = irq_domain_xlate_onetwocell,
 	.map = icu_map,
 };

 int __init icu_of_init(struct device_node *node, struct device_node *parent)
 {
 	struct device_node *eiu_node;
 	struct resource res;
 	int i, ret, vpe;

 	/* load register regions of available ICUs */
 	for_each_possible_cpu(vpe) {
 		if (of_address_to_resource(node, vpe, &res))
 			panic("Failed to get icu%i memory range", vpe);

 		if (!request_mem_region(res.start, resource_size(&res),
 					res.name))
 			pr_err("Failed to request icu%i memory\n", vpe);

 		ltq_icu_membase[vpe] = ioremap(res.start,
 					resource_size(&res));

 		if (!ltq_icu_membase[vpe])
 			panic("Failed to remap icu%i memory", vpe);
 	}

 	/* turn off all irqs by default */
 	for_each_possible_cpu(vpe) {
 		for (i = 0; i < MAX_IM; i++) {
 			/* make sure all irqs are turned off by default */
 			ltq_icu_w32(vpe, i, 0, LTQ_ICU_IER);

 			/* clear all possibly pending interrupts */
 			ltq_icu_w32(vpe, i, ~0, LTQ_ICU_ISR);
 			ltq_icu_w32(vpe, i, ~0, LTQ_ICU_IMR);

 			/* clear resend */
 			ltq_icu_w32(vpe, i, 0, LTQ_ICU_IRSR);
 		}
 	}

 	mips_cpu_irq_init();

 	for (i = 0; i < MAX_IM; i++)
 		irq_set_chained_handler(i + 2, ltq_hw_irq_handler);

 	ltq_domain = irq_domain_add_linear(node,
 		(MAX_IM * INT_NUM_IM_OFFSET) + MIPS_CPU_IRQ_CASCADE,
 		&irq_domain_ops, 0);

 	/* tell oprofile which irq to use */
 	ltq_perfcount_irq = irq_create_mapping(ltq_domain, LTQ_PERF_IRQ);

 	/* the external interrupts are optional and xway only */
 	eiu_node = of_find_compatible_node(NULL, NULL, "lantiq,eiu-xway");
 	if (eiu_node && !of_address_to_resource(eiu_node, 0, &res)) {
 		/* find out how many external irq sources we have */
 		exin_avail = of_property_count_u32_elems(eiu_node,
 							 "lantiq,eiu-irqs");

 		if (exin_avail > MAX_EIU)
 			exin_avail = MAX_EIU;

 		ret = of_property_read_u32_array(eiu_node, "lantiq,eiu-irqs",
 						ltq_eiu_irq, exin_avail);
 		if (ret)
 			panic("failed to load external irq resources");

 		if (!request_mem_region(res.start, resource_size(&res),
 							res.name))
 			pr_err("Failed to request eiu memory");

 		ltq_eiu_membase = ioremap(res.start,
 							resource_size(&res));
 		if (!ltq_eiu_membase)
 			panic("Failed to remap eiu memory");
 	}
 	of_node_put(eiu_node);

 	return 0;
 }

 int get_c0_perfcount_int(void)
 {
 	return ltq_perfcount_irq;
 }
 EXPORT_SYMBOL_GPL(get_c0_perfcount_int);

 unsigned int get_c0_compare_int(void)
 {
 	return CP0_LEGACY_COMPARE_IRQ;
 }

 IRQCHIP_DECLARE(lantiq_icu, "lantiq,icu", icu_of_init);

 void __init arch_init_irq(void)
 {
 	irqchip_init();
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	*
	* Copyright (C) 2010 John Crispin <john@phrozen.org>
	* Copyright (C) 2010 Thomas Langer <thomas.langer@lantiq.com>
	*/

	#include <linux/interrupt.h>
	#include <linux/ioport.h>
	#include <linux/sched.h>
	#include <linux/irqchip.h>
	#include <linux/irqdomain.h>
	#include <linux/of_platform.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>

	#include <asm/bootinfo.h>
	#include <asm/irq_cpu.h>

	#include <lantiq_soc.h>
	#include <irq.h>

	/* register definitions - internal irqs */
	#define LTQ_ICU_ISR 0x0000
	#define LTQ_ICU_IER 0x0008
	#define LTQ_ICU_IOSR 0x0010
	#define LTQ_ICU_IRSR 0x0018
	#define LTQ_ICU_IMR 0x0020

	#define LTQ_ICU_IM_SIZE 0x28

	/* register definitions - external irqs */
	#define LTQ_EIU_EXIN_C 0x0000
	#define LTQ_EIU_EXIN_INIC 0x0004
	#define LTQ_EIU_EXIN_INC 0x0008
	#define LTQ_EIU_EXIN_INEN 0x000C

	/* number of external interrupts */
	#define MAX_EIU 6

	/* the performance counter */
	#define LTQ_PERF_IRQ (INT_NUM_IM4_IRL0 + 31)

	/*
	* irqs generated by devices attached to the EBU need to be acked in
	* a special manner
	*/
	#define LTQ_ICU_EBU_IRQ 22

	#define ltq_icu_w32(vpe, m, x, y) \
	ltq_w32((x), ltq_icu_membase[vpe] + m*LTQ_ICU_IM_SIZE + (y))

	#define ltq_icu_r32(vpe, m, x) \
	ltq_r32(ltq_icu_membase[vpe] + m*LTQ_ICU_IM_SIZE + (x))

	#define ltq_eiu_w32(x, y) ltq_w32((x), ltq_eiu_membase + (y))
	#define ltq_eiu_r32(x) ltq_r32(ltq_eiu_membase + (x))

	/* we have a cascade of 8 irqs */
	#define MIPS_CPU_IRQ_CASCADE 8

	static int exin_avail;
	static u32 ltq_eiu_irq[MAX_EIU];
	static void __iomem *ltq_icu_membase[NR_CPUS];
	static void __iomem *ltq_eiu_membase;
	static struct irq_domain *ltq_domain;
	static DEFINE_SPINLOCK(ltq_eiu_lock);
	static DEFINE_RAW_SPINLOCK(ltq_icu_lock);
	static int ltq_perfcount_irq;

	int ltq_eiu_get_irq(int exin)
	{
	if (exin < exin_avail)
	return ltq_eiu_irq[exin];
	return -1;
	}

	void ltq_disable_irq(struct irq_data *d)
	{
	unsigned long offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
	unsigned long im = offset / INT_NUM_IM_OFFSET;
	unsigned long flags;
	int vpe;

	offset %= INT_NUM_IM_OFFSET;

	raw_spin_lock_irqsave(&ltq_icu_lock, flags);
	for_each_present_cpu(vpe) {
	ltq_icu_w32(vpe, im,
	ltq_icu_r32(vpe, im, LTQ_ICU_IER) & ~BIT(offset),
	LTQ_ICU_IER);
	}
	raw_spin_unlock_irqrestore(&ltq_icu_lock, flags);
	}

	void ltq_mask_and_ack_irq(struct irq_data *d)
	{
	unsigned long offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
	unsigned long im = offset / INT_NUM_IM_OFFSET;
	unsigned long flags;
	int vpe;

	offset %= INT_NUM_IM_OFFSET;

	raw_spin_lock_irqsave(&ltq_icu_lock, flags);
	for_each_present_cpu(vpe) {
	ltq_icu_w32(vpe, im,
	ltq_icu_r32(vpe, im, LTQ_ICU_IER) & ~BIT(offset),
	LTQ_ICU_IER);
	ltq_icu_w32(vpe, im, BIT(offset), LTQ_ICU_ISR);
	}
	raw_spin_unlock_irqrestore(&ltq_icu_lock, flags);
	}

	static void ltq_ack_irq(struct irq_data *d)
	{
	unsigned long offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
	unsigned long im = offset / INT_NUM_IM_OFFSET;
	unsigned long flags;
	int vpe;

	offset %= INT_NUM_IM_OFFSET;

	raw_spin_lock_irqsave(&ltq_icu_lock, flags);
	for_each_present_cpu(vpe) {
	ltq_icu_w32(vpe, im, BIT(offset), LTQ_ICU_ISR);
	}
	raw_spin_unlock_irqrestore(&ltq_icu_lock, flags);
	}

	void ltq_enable_irq(struct irq_data *d)
	{
	unsigned long offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
	unsigned long im = offset / INT_NUM_IM_OFFSET;
	unsigned long flags;
	int vpe;

	offset %= INT_NUM_IM_OFFSET;

	vpe = cpumask_first(irq_data_get_effective_affinity_mask(d));

	/* This shouldn't be even possible, maybe during CPU hotplug spam */
	if (unlikely(vpe >= nr_cpu_ids))
	vpe = smp_processor_id();

	raw_spin_lock_irqsave(&ltq_icu_lock, flags);

	ltq_icu_w32(vpe, im, ltq_icu_r32(vpe, im, LTQ_ICU_IER) \| BIT(offset),
	LTQ_ICU_IER);

	raw_spin_unlock_irqrestore(&ltq_icu_lock, flags);
	}

	static int ltq_eiu_settype(struct irq_data *d, unsigned int type)
	{
	int i;
	unsigned long flags;

	for (i = 0; i < exin_avail; i++) {
	if (d->hwirq == ltq_eiu_irq[i]) {
	int val = 0;
	int edge = 0;

	switch (type) {
	case IRQF_TRIGGER_NONE:
	break;
	case IRQF_TRIGGER_RISING:
	val = 1;
	edge = 1;
	break;
	case IRQF_TRIGGER_FALLING:
	val = 2;
	edge = 1;
	break;
	case IRQF_TRIGGER_RISING \| IRQF_TRIGGER_FALLING:
	val = 3;
	edge = 1;
	break;
	case IRQF_TRIGGER_HIGH:
	val = 5;
	break;
	case IRQF_TRIGGER_LOW:
	val = 6;
	break;
	default:
	pr_err("invalid type %d for irq %ld\n",
	type, d->hwirq);
	return -EINVAL;
	}

	if (edge)
	irq_set_handler(d->hwirq, handle_edge_irq);

	spin_lock_irqsave(&ltq_eiu_lock, flags);
	ltq_eiu_w32((ltq_eiu_r32(LTQ_EIU_EXIN_C) &
	(~(7 << (i * 4)))) \| (val << (i * 4)),
	LTQ_EIU_EXIN_C);
	spin_unlock_irqrestore(&ltq_eiu_lock, flags);
	}
	}

	return 0;
	}

	static unsigned int ltq_startup_eiu_irq(struct irq_data *d)
	{
	int i;

	ltq_enable_irq(d);
	for (i = 0; i < exin_avail; i++) {
	if (d->hwirq == ltq_eiu_irq[i]) {
	/* by default we are low level triggered */
	ltq_eiu_settype(d, IRQF_TRIGGER_LOW);
	/* clear all pending */
	ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INC) & ~BIT(i),
	LTQ_EIU_EXIN_INC);
	/* enable */
	ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INEN) \| BIT(i),
	LTQ_EIU_EXIN_INEN);
	break;
	}
	}

	return 0;
	}

	static void ltq_shutdown_eiu_irq(struct irq_data *d)
	{
	int i;

	ltq_disable_irq(d);
	for (i = 0; i < exin_avail; i++) {
	if (d->hwirq == ltq_eiu_irq[i]) {
	/* disable */
	ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INEN) & ~BIT(i),
	LTQ_EIU_EXIN_INEN);
	break;
	}
	}
	}

	#if defined(CONFIG_SMP)
	static int ltq_icu_irq_set_affinity(struct irq_data *d,
	const struct cpumask *cpumask, bool force)
	{
	struct cpumask tmask;

	if (!cpumask_and(&tmask, cpumask, cpu_online_mask))
	return -EINVAL;

	irq_data_update_effective_affinity(d, &tmask);

	return IRQ_SET_MASK_OK;
	}
	#endif

	static struct irq_chip ltq_irq_type = {
	.name = "icu",
	.irq_enable = ltq_enable_irq,
	.irq_disable = ltq_disable_irq,
	.irq_unmask = ltq_enable_irq,
	.irq_ack = ltq_ack_irq,
	.irq_mask = ltq_disable_irq,
	.irq_mask_ack = ltq_mask_and_ack_irq,
	#if defined(CONFIG_SMP)
	.irq_set_affinity = ltq_icu_irq_set_affinity,
	#endif
	};

	static struct irq_chip ltq_eiu_type = {
	.name = "eiu",
	.irq_startup = ltq_startup_eiu_irq,
	.irq_shutdown = ltq_shutdown_eiu_irq,
	.irq_enable = ltq_enable_irq,
	.irq_disable = ltq_disable_irq,
	.irq_unmask = ltq_enable_irq,
	.irq_ack = ltq_ack_irq,
	.irq_mask = ltq_disable_irq,
	.irq_mask_ack = ltq_mask_and_ack_irq,
	.irq_set_type = ltq_eiu_settype,
	#if defined(CONFIG_SMP)
	.irq_set_affinity = ltq_icu_irq_set_affinity,
	#endif
	};

	static void ltq_hw_irq_handler(struct irq_desc *desc)
	{
	unsigned int module = irq_desc_get_irq(desc) - 2;
	u32 irq;
	irq_hw_number_t hwirq;
	int vpe = smp_processor_id();

	irq = ltq_icu_r32(vpe, module, LTQ_ICU_IOSR);
	if (irq == 0)
	return;

	/*
	* silicon bug causes only the msb set to 1 to be valid. all
	* other bits might be bogus
	*/
	irq = __fls(irq);
	hwirq = irq + MIPS_CPU_IRQ_CASCADE + (INT_NUM_IM_OFFSET * module);
	generic_handle_domain_irq(ltq_domain, hwirq);

	/* if this is a EBU irq, we need to ack it or get a deadlock */
	if (irq == LTQ_ICU_EBU_IRQ && !module && LTQ_EBU_PCC_ISTAT != 0)
	ltq_ebu_w32(ltq_ebu_r32(LTQ_EBU_PCC_ISTAT) \| 0x10,
	LTQ_EBU_PCC_ISTAT);
	}

	static int icu_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
	{
	struct irq_chip *chip = &ltq_irq_type;
	struct irq_data *data;
	int i;

	if (hw < MIPS_CPU_IRQ_CASCADE)
	return 0;

	for (i = 0; i < exin_avail; i++)
	if (hw == ltq_eiu_irq[i])
	chip = &ltq_eiu_type;

	data = irq_get_irq_data(irq);

	irq_data_update_effective_affinity(data, cpumask_of(0));

	irq_set_chip_and_handler(irq, chip, handle_level_irq);

	return 0;
	}

	static const struct irq_domain_ops irq_domain_ops = {
	.xlate = irq_domain_xlate_onetwocell,
	.map = icu_map,
	};

	int __init icu_of_init(struct device_node node, struct device_node parent)
	{
	struct device_node *eiu_node;
	struct resource res;
	int i, ret, vpe;

	/* load register regions of available ICUs */
	for_each_possible_cpu(vpe) {
	if (of_address_to_resource(node, vpe, &res))
	panic("Failed to get icu%i memory range", vpe);

	if (!request_mem_region(res.start, resource_size(&res),
	res.name))
	pr_err("Failed to request icu%i memory\n", vpe);

	ltq_icu_membase[vpe] = ioremap(res.start,
	resource_size(&res));

	if (!ltq_icu_membase[vpe])
	panic("Failed to remap icu%i memory", vpe);
	}

	/* turn off all irqs by default */
	for_each_possible_cpu(vpe) {
	for (i = 0; i < MAX_IM; i++) {
	/* make sure all irqs are turned off by default */
	ltq_icu_w32(vpe, i, 0, LTQ_ICU_IER);

	/* clear all possibly pending interrupts */
	ltq_icu_w32(vpe, i, ~0, LTQ_ICU_ISR);
	ltq_icu_w32(vpe, i, ~0, LTQ_ICU_IMR);

	/* clear resend */
	ltq_icu_w32(vpe, i, 0, LTQ_ICU_IRSR);
	}
	}

	mips_cpu_irq_init();

	for (i = 0; i < MAX_IM; i++)
	irq_set_chained_handler(i + 2, ltq_hw_irq_handler);

	ltq_domain = irq_domain_add_linear(node,
	(MAX_IM * INT_NUM_IM_OFFSET) + MIPS_CPU_IRQ_CASCADE,
	&irq_domain_ops, 0);

	/* tell oprofile which irq to use */
	ltq_perfcount_irq = irq_create_mapping(ltq_domain, LTQ_PERF_IRQ);

	/* the external interrupts are optional and xway only */
	eiu_node = of_find_compatible_node(NULL, NULL, "lantiq,eiu-xway");
	if (eiu_node && !of_address_to_resource(eiu_node, 0, &res)) {
	/* find out how many external irq sources we have */
	exin_avail = of_property_count_u32_elems(eiu_node,
	"lantiq,eiu-irqs");

	if (exin_avail > MAX_EIU)
	exin_avail = MAX_EIU;

	ret = of_property_read_u32_array(eiu_node, "lantiq,eiu-irqs",
	ltq_eiu_irq, exin_avail);
	if (ret)
	panic("failed to load external irq resources");

	if (!request_mem_region(res.start, resource_size(&res),
	res.name))
	pr_err("Failed to request eiu memory");

	ltq_eiu_membase = ioremap(res.start,
	resource_size(&res));
	if (!ltq_eiu_membase)
	panic("Failed to remap eiu memory");
	}
	of_node_put(eiu_node);

	return 0;
	}

	int get_c0_perfcount_int(void)
	{
	return ltq_perfcount_irq;
	}
	EXPORT_SYMBOL_GPL(get_c0_perfcount_int);

	unsigned int get_c0_compare_int(void)
	{
	return CP0_LEGACY_COMPARE_IRQ;
	}

	IRQCHIP_DECLARE(lantiq_icu, "lantiq,icu", icu_of_init);

	void __init arch_init_irq(void)
	{
	irqchip_init();
	}