arch/powerpc/platforms/iseries/irq.c - kernel/msm-4.9 - Gitiles

 /*
  * This module supports the iSeries PCI bus interrupt handling
  * Copyright (C) 20yy  <Robert L Holtorf> <IBM Corp>
  * Copyright (C) 2004-2005 IBM Corporation
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the:
  * Free Software Foundation, Inc.,
  * 59 Temple Place, Suite 330,
  * Boston, MA  02111-1307  USA
  *
  * Change Activity:
  *   Created, December 13, 2000 by Wayne Holm
  * End Change Activity
  */
 #include <linux/pci.h>
 #include <linux/init.h>
 #include <linux/threads.h>
 #include <linux/smp.h>
 #include <linux/param.h>
 #include <linux/string.h>
 #include <linux/bootmem.h>
 #include <linux/irq.h>
 #include <linux/spinlock.h>

 #include <asm/paca.h>
 #include <asm/iseries/hv_types.h>
 #include <asm/iseries/hv_lp_event.h>
 #include <asm/iseries/hv_call_xm.h>
 #include <asm/iseries/it_lp_queue.h>

 #include "irq.h"
 #include "pci.h"
 #include "call_pci.h"

 #ifdef CONFIG_PCI

 enum pci_event_type {
 	pe_bus_created		= 0,	/* PHB has been created */
 	pe_bus_error		= 1,	/* PHB has failed */
 	pe_bus_failed		= 2,	/* Msg to Secondary, Primary failed bus */
 	pe_node_failed		= 4,	/* Multi-adapter bridge has failed */
 	pe_node_recovered	= 5,	/* Multi-adapter bridge has recovered */
 	pe_bus_recovered	= 12,	/* PHB has been recovered */
 	pe_unquiese_bus		= 18,	/* Secondary bus unqiescing */
 	pe_bridge_error		= 21,	/* Bridge Error */
 	pe_slot_interrupt	= 22	/* Slot interrupt */
 };

 struct pci_event {
 	struct HvLpEvent event;
 	union {
 		u64 __align;		/* Align on an 8-byte boundary */
 		struct {
 			u32		fisr;
 			HvBusNumber	bus_number;
 			HvSubBusNumber	sub_bus_number;
 			HvAgentId	dev_id;
 		} slot;
 		struct {
 			HvBusNumber	bus_number;
 			HvSubBusNumber	sub_bus_number;
 		} bus;
 		struct {
 			HvBusNumber	bus_number;
 			HvSubBusNumber	sub_bus_number;
 			HvAgentId	dev_id;
 		} node;
 	} data;
 };

 static DEFINE_SPINLOCK(pending_irqs_lock);
 static int num_pending_irqs;
 static int pending_irqs[NR_IRQS];

 static void int_received(struct pci_event *event)
 {
 	int irq;

 	switch (event->event.xSubtype) {
 	case pe_slot_interrupt:
 		irq = event->event.xCorrelationToken;
 		if (irq < NR_IRQS) {
 			spin_lock(&pending_irqs_lock);
 			pending_irqs[irq]++;
 			num_pending_irqs++;
 			spin_unlock(&pending_irqs_lock);
 		} else {
 			printk(KERN_WARNING "int_received: bad irq number %d\n",
 					irq);
 			HvCallPci_eoi(event->data.slot.bus_number,
 					event->data.slot.sub_bus_number,
 					event->data.slot.dev_id);
 		}
 		break;
 		/* Ignore error recovery events for now */
 	case pe_bus_created:
 		printk(KERN_INFO "int_received: system bus %d created\n",
 			event->data.bus.bus_number);
 		break;
 	case pe_bus_error:
 	case pe_bus_failed:
 		printk(KERN_INFO "int_received: system bus %d failed\n",
 			event->data.bus.bus_number);
 		break;
 	case pe_bus_recovered:
 	case pe_unquiese_bus:
 		printk(KERN_INFO "int_received: system bus %d recovered\n",
 			event->data.bus.bus_number);
 		break;
 	case pe_node_failed:
 	case pe_bridge_error:
 		printk(KERN_INFO
 			"int_received: multi-adapter bridge %d/%d/%d failed\n",
 			event->data.node.bus_number,
 			event->data.node.sub_bus_number,
 			event->data.node.dev_id);
 		break;
 	case pe_node_recovered:
 		printk(KERN_INFO
 			"int_received: multi-adapter bridge %d/%d/%d recovered\n",
 			event->data.node.bus_number,
 			event->data.node.sub_bus_number,
 			event->data.node.dev_id);
 		break;
 	default:
 		printk(KERN_ERR
 			"int_received: unrecognized event subtype 0x%x\n",
 			event->event.xSubtype);
 		break;
 	}
 }

 static void pci_event_handler(struct HvLpEvent *event)
 {
 	if (event && (event->xType == HvLpEvent_Type_PciIo)) {
 		if (hvlpevent_is_int(event))
 			int_received((struct pci_event *)event);
 		else
 			printk(KERN_ERR
 				"pci_event_handler: unexpected ack received\n");
 	} else if (event)
 		printk(KERN_ERR
 			"pci_event_handler: Unrecognized PCI event type 0x%x\n",
 			(int)event->xType);
 	else
 		printk(KERN_ERR "pci_event_handler: NULL event received\n");
 }

 #define REAL_IRQ_TO_SUBBUS(irq)	(((irq) >> 14) & 0xff)
 #define REAL_IRQ_TO_BUS(irq)	((((irq) >> 6) & 0xff) + 1)
 #define REAL_IRQ_TO_IDSEL(irq)	((((irq) >> 3) & 7) + 1)
 #define REAL_IRQ_TO_FUNC(irq)	((irq) & 7)

 /*
  * This will be called by device drivers (via enable_IRQ)
  * to enable INTA in the bridge interrupt status register.
  */
 static void iseries_enable_IRQ(struct irq_data *d)
 {
 	u32 bus, dev_id, function, mask;
 	const u32 sub_bus = 0;
 	unsigned int rirq = (unsigned int)irqd_to_hwirq(d);

 	/* The IRQ has already been locked by the caller */
 	bus = REAL_IRQ_TO_BUS(rirq);
 	function = REAL_IRQ_TO_FUNC(rirq);
 	dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

 	/* Unmask secondary INTA */
 	mask = 0x80000000;
 	HvCallPci_unmaskInterrupts(bus, sub_bus, dev_id, mask);
 }

 /* This is called by iseries_activate_IRQs */
 static unsigned int iseries_startup_IRQ(struct irq_data *d)
 {
 	u32 bus, dev_id, function, mask;
 	const u32 sub_bus = 0;
 	unsigned int rirq = (unsigned int)irqd_to_hwirq(d);

 	bus = REAL_IRQ_TO_BUS(rirq);
 	function = REAL_IRQ_TO_FUNC(rirq);
 	dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

 	/* Link the IRQ number to the bridge */
 	HvCallXm_connectBusUnit(bus, sub_bus, dev_id, d->irq);

 	/* Unmask bridge interrupts in the FISR */
 	mask = 0x01010000 << function;
 	HvCallPci_unmaskFisr(bus, sub_bus, dev_id, mask);
 	iseries_enable_IRQ(d);
 	return 0;
 }

 /*
  * This is called out of iSeries_fixup to activate interrupt
  * generation for usable slots
  */
 void __init iSeries_activate_IRQs()
 {
 	int irq;
 	unsigned long flags;

 	for_each_irq (irq) {
 		struct irq_desc *desc = irq_to_desc(irq);
 		struct irq_chip *chip;

 		if (!desc)
 			continue;

 		chip = irq_desc_get_chip(desc);
 		if (chip && chip->irq_startup) {
 			raw_spin_lock_irqsave(&desc->lock, flags);
 			chip->irq_startup(&desc->irq_data);
 			raw_spin_unlock_irqrestore(&desc->lock, flags);
 		}
 	}
 }

 /*  this is not called anywhere currently */
 static void iseries_shutdown_IRQ(struct irq_data *d)
 {
 	u32 bus, dev_id, function, mask;
 	const u32 sub_bus = 0;
 	unsigned int rirq = (unsigned int)irqd_to_hwirq(d);

 	/* irq should be locked by the caller */
 	bus = REAL_IRQ_TO_BUS(rirq);
 	function = REAL_IRQ_TO_FUNC(rirq);
 	dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

 	/* Invalidate the IRQ number in the bridge */
 	HvCallXm_connectBusUnit(bus, sub_bus, dev_id, 0);

 	/* Mask bridge interrupts in the FISR */
 	mask = 0x01010000 << function;
 	HvCallPci_maskFisr(bus, sub_bus, dev_id, mask);
 }

 /*
  * This will be called by device drivers (via disable_IRQ)
  * to disable INTA in the bridge interrupt status register.
  */
 static void iseries_disable_IRQ(struct irq_data *d)
 {
 	u32 bus, dev_id, function, mask;
 	const u32 sub_bus = 0;
 	unsigned int rirq = (unsigned int)irqd_to_hwirq(d);

 	/* The IRQ has already been locked by the caller */
 	bus = REAL_IRQ_TO_BUS(rirq);
 	function = REAL_IRQ_TO_FUNC(rirq);
 	dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

 	/* Mask secondary INTA   */
 	mask = 0x80000000;
 	HvCallPci_maskInterrupts(bus, sub_bus, dev_id, mask);
 }

 static void iseries_end_IRQ(struct irq_data *d)
 {
 	unsigned int rirq = (unsigned int)irqd_to_hwirq(d);

 	HvCallPci_eoi(REAL_IRQ_TO_BUS(rirq), REAL_IRQ_TO_SUBBUS(rirq),
 		(REAL_IRQ_TO_IDSEL(rirq) << 4) + REAL_IRQ_TO_FUNC(rirq));
 }

 static struct irq_chip iseries_pic = {
 	.name		= "iSeries",
 	.irq_startup	= iseries_startup_IRQ,
 	.irq_shutdown	= iseries_shutdown_IRQ,
 	.irq_unmask	= iseries_enable_IRQ,
 	.irq_mask	= iseries_disable_IRQ,
 	.irq_eoi	= iseries_end_IRQ
 };

 /*
  * This is called out of iSeries_scan_slot to allocate an IRQ for an EADS slot
  * It calculates the irq value for the slot.
  * Note that sub_bus is always 0 (at the moment at least).
  */
 int __init iSeries_allocate_IRQ(HvBusNumber bus,
 		HvSubBusNumber sub_bus, u32 bsubbus)
 {
 	unsigned int realirq;
 	u8 idsel = ISERIES_GET_DEVICE_FROM_SUBBUS(bsubbus);
 	u8 function = ISERIES_GET_FUNCTION_FROM_SUBBUS(bsubbus);

 	realirq = (((((sub_bus << 8) + (bus - 1)) << 3) + (idsel - 1)) << 3)
 		+ function;

 	return irq_create_mapping(NULL, realirq);
 }

 #endif /* CONFIG_PCI */

 /*
  * Get the next pending IRQ.
  */
 unsigned int iSeries_get_irq(void)
 {
 	int irq = NO_IRQ_IGNORE;

 #ifdef CONFIG_SMP
 	if (get_lppaca()->int_dword.fields.ipi_cnt) {
 		get_lppaca()->int_dword.fields.ipi_cnt = 0;
 		smp_ipi_demux();
 	}
 #endif /* CONFIG_SMP */
 	if (hvlpevent_is_pending())
 		process_hvlpevents();

 #ifdef CONFIG_PCI
 	if (num_pending_irqs) {
 		spin_lock(&pending_irqs_lock);
 		for (irq = 0; irq < NR_IRQS; irq++) {
 			if (pending_irqs[irq]) {
 				pending_irqs[irq]--;
 				num_pending_irqs--;
 				break;
 			}
 		}
 		spin_unlock(&pending_irqs_lock);
 		if (irq >= NR_IRQS)
 			irq = NO_IRQ_IGNORE;
 	}
 #endif

 	return irq;
 }

 #ifdef CONFIG_PCI

 static int iseries_irq_host_map(struct irq_host *h, unsigned int virq,
 				irq_hw_number_t hw)
 {
 	irq_set_chip_and_handler(virq, &iseries_pic, handle_fasteoi_irq);

 	return 0;
 }

 static int iseries_irq_host_match(struct irq_host *h, struct device_node *np)
 {
 	/* Match all */
 	return 1;
 }

 static struct irq_host_ops iseries_irq_host_ops = {
 	.map = iseries_irq_host_map,
 	.match = iseries_irq_host_match,
 };

 /*
  * This is called by init_IRQ.  set in ppc_md.init_IRQ by iSeries_setup.c
  * It must be called before the bus walk.
  */
 void __init iSeries_init_IRQ(void)
 {
 	/* Register PCI event handler and open an event path */
 	struct irq_host *host;
 	int ret;

 	/*
 	 * The Hypervisor only allows us up to 256 interrupt
 	 * sources (the irq number is passed in a u8).
 	 */
 	irq_set_virq_count(256);

 	/* Create irq host. No need for a revmap since HV will give us
 	 * back our virtual irq number
 	 */
 	host = irq_alloc_host(NULL, IRQ_HOST_MAP_NOMAP, 0,
 			      &iseries_irq_host_ops, 0);
 	BUG_ON(host == NULL);
 	irq_set_default_host(host);

 	ret = HvLpEvent_registerHandler(HvLpEvent_Type_PciIo,
 			&pci_event_handler);
 	if (ret == 0) {
 		ret = HvLpEvent_openPath(HvLpEvent_Type_PciIo, 0);
 		if (ret != 0)
 			printk(KERN_ERR "iseries_init_IRQ: open event path "
 					"failed with rc 0x%x\n", ret);
 	} else
 		printk(KERN_ERR "iseries_init_IRQ: register handler "
 				"failed with rc 0x%x\n", ret);
 }

 #endif	/* CONFIG_PCI */
	/*
	* This module supports the iSeries PCI bus interrupt handling
	* Copyright (C) 20yy <Robert L Holtorf> <IBM Corp>
	* Copyright (C) 2004-2005 IBM Corporation
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the:
	* Free Software Foundation, Inc.,
	* 59 Temple Place, Suite 330,
	* Boston, MA 02111-1307 USA
	*
	* Change Activity:
	* Created, December 13, 2000 by Wayne Holm
	* End Change Activity
	*/
	#include <linux/pci.h>
	#include <linux/init.h>
	#include <linux/threads.h>
	#include <linux/smp.h>
	#include <linux/param.h>
	#include <linux/string.h>
	#include <linux/bootmem.h>
	#include <linux/irq.h>
	#include <linux/spinlock.h>

	#include <asm/paca.h>
	#include <asm/iseries/hv_types.h>
	#include <asm/iseries/hv_lp_event.h>
	#include <asm/iseries/hv_call_xm.h>
	#include <asm/iseries/it_lp_queue.h>

	#include "irq.h"
	#include "pci.h"
	#include "call_pci.h"

	#ifdef CONFIG_PCI

	enum pci_event_type {
	pe_bus_created = 0, /* PHB has been created */
	pe_bus_error = 1, /* PHB has failed */
	pe_bus_failed = 2, /* Msg to Secondary, Primary failed bus */
	pe_node_failed = 4, /* Multi-adapter bridge has failed */
	pe_node_recovered = 5, /* Multi-adapter bridge has recovered */
	pe_bus_recovered = 12, /* PHB has been recovered */
	pe_unquiese_bus = 18, /* Secondary bus unqiescing */
	pe_bridge_error = 21, /* Bridge Error */
	pe_slot_interrupt = 22 /* Slot interrupt */
	};

	struct pci_event {
	struct HvLpEvent event;
	union {
	u64 __align; /* Align on an 8-byte boundary */
	struct {
	u32 fisr;
	HvBusNumber bus_number;
	HvSubBusNumber sub_bus_number;
	HvAgentId dev_id;
	} slot;
	struct {
	HvBusNumber bus_number;
	HvSubBusNumber sub_bus_number;
	} bus;
	struct {
	HvBusNumber bus_number;
	HvSubBusNumber sub_bus_number;
	HvAgentId dev_id;
	} node;
	} data;
	};

	static DEFINE_SPINLOCK(pending_irqs_lock);
	static int num_pending_irqs;
	static int pending_irqs[NR_IRQS];

	static void int_received(struct pci_event *event)
	{
	int irq;

	switch (event->event.xSubtype) {
	case pe_slot_interrupt:
	irq = event->event.xCorrelationToken;
	if (irq < NR_IRQS) {
	spin_lock(&pending_irqs_lock);
	pending_irqs[irq]++;
	num_pending_irqs++;
	spin_unlock(&pending_irqs_lock);
	} else {
	printk(KERN_WARNING "int_received: bad irq number %d\n",
	irq);
	HvCallPci_eoi(event->data.slot.bus_number,
	event->data.slot.sub_bus_number,
	event->data.slot.dev_id);
	}
	break;
	/* Ignore error recovery events for now */
	case pe_bus_created:
	printk(KERN_INFO "int_received: system bus %d created\n",
	event->data.bus.bus_number);
	break;
	case pe_bus_error:
	case pe_bus_failed:
	printk(KERN_INFO "int_received: system bus %d failed\n",
	event->data.bus.bus_number);
	break;
	case pe_bus_recovered:
	case pe_unquiese_bus:
	printk(KERN_INFO "int_received: system bus %d recovered\n",
	event->data.bus.bus_number);
	break;
	case pe_node_failed:
	case pe_bridge_error:
	printk(KERN_INFO
	"int_received: multi-adapter bridge %d/%d/%d failed\n",
	event->data.node.bus_number,
	event->data.node.sub_bus_number,
	event->data.node.dev_id);
	break;
	case pe_node_recovered:
	printk(KERN_INFO
	"int_received: multi-adapter bridge %d/%d/%d recovered\n",
	event->data.node.bus_number,
	event->data.node.sub_bus_number,
	event->data.node.dev_id);
	break;
	default:
	printk(KERN_ERR
	"int_received: unrecognized event subtype 0x%x\n",
	event->event.xSubtype);
	break;
	}
	}

	static void pci_event_handler(struct HvLpEvent *event)
	{
	if (event && (event->xType == HvLpEvent_Type_PciIo)) {
	if (hvlpevent_is_int(event))
	int_received((struct pci_event *)event);
	else
	printk(KERN_ERR
	"pci_event_handler: unexpected ack received\n");
	} else if (event)
	printk(KERN_ERR
	"pci_event_handler: Unrecognized PCI event type 0x%x\n",
	(int)event->xType);
	else
	printk(KERN_ERR "pci_event_handler: NULL event received\n");
	}

	#define REAL_IRQ_TO_SUBBUS(irq) (((irq) >> 14) & 0xff)
	#define REAL_IRQ_TO_BUS(irq) ((((irq) >> 6) & 0xff) + 1)
	#define REAL_IRQ_TO_IDSEL(irq) ((((irq) >> 3) & 7) + 1)
	#define REAL_IRQ_TO_FUNC(irq) ((irq) & 7)

	/*
	* This will be called by device drivers (via enable_IRQ)
	* to enable INTA in the bridge interrupt status register.
	*/
	static void iseries_enable_IRQ(struct irq_data *d)
	{
	u32 bus, dev_id, function, mask;
	const u32 sub_bus = 0;
	unsigned int rirq = (unsigned int)irqd_to_hwirq(d);

	/* The IRQ has already been locked by the caller */
	bus = REAL_IRQ_TO_BUS(rirq);
	function = REAL_IRQ_TO_FUNC(rirq);
	dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

	/* Unmask secondary INTA */
	mask = 0x80000000;
	HvCallPci_unmaskInterrupts(bus, sub_bus, dev_id, mask);
	}

	/* This is called by iseries_activate_IRQs */
	static unsigned int iseries_startup_IRQ(struct irq_data *d)
	{
	u32 bus, dev_id, function, mask;
	const u32 sub_bus = 0;
	unsigned int rirq = (unsigned int)irqd_to_hwirq(d);

	bus = REAL_IRQ_TO_BUS(rirq);
	function = REAL_IRQ_TO_FUNC(rirq);
	dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

	/* Link the IRQ number to the bridge */
	HvCallXm_connectBusUnit(bus, sub_bus, dev_id, d->irq);

	/* Unmask bridge interrupts in the FISR */
	mask = 0x01010000 << function;
	HvCallPci_unmaskFisr(bus, sub_bus, dev_id, mask);
	iseries_enable_IRQ(d);
	return 0;
	}

	/*
	* This is called out of iSeries_fixup to activate interrupt
	* generation for usable slots
	*/
	void __init iSeries_activate_IRQs()
	{
	int irq;
	unsigned long flags;

	for_each_irq (irq) {
	struct irq_desc *desc = irq_to_desc(irq);
	struct irq_chip *chip;

	if (!desc)
	continue;

	chip = irq_desc_get_chip(desc);
	if (chip && chip->irq_startup) {
	raw_spin_lock_irqsave(&desc->lock, flags);
	chip->irq_startup(&desc->irq_data);
	raw_spin_unlock_irqrestore(&desc->lock, flags);
	}
	}
	}

	/* this is not called anywhere currently */
	static void iseries_shutdown_IRQ(struct irq_data *d)
	{
	u32 bus, dev_id, function, mask;
	const u32 sub_bus = 0;
	unsigned int rirq = (unsigned int)irqd_to_hwirq(d);

	/* irq should be locked by the caller */
	bus = REAL_IRQ_TO_BUS(rirq);
	function = REAL_IRQ_TO_FUNC(rirq);
	dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

	/* Invalidate the IRQ number in the bridge */
	HvCallXm_connectBusUnit(bus, sub_bus, dev_id, 0);

	/* Mask bridge interrupts in the FISR */
	mask = 0x01010000 << function;
	HvCallPci_maskFisr(bus, sub_bus, dev_id, mask);
	}

	/*
	* This will be called by device drivers (via disable_IRQ)
	* to disable INTA in the bridge interrupt status register.
	*/
	static void iseries_disable_IRQ(struct irq_data *d)
	{
	u32 bus, dev_id, function, mask;
	const u32 sub_bus = 0;
	unsigned int rirq = (unsigned int)irqd_to_hwirq(d);

	/* The IRQ has already been locked by the caller */
	bus = REAL_IRQ_TO_BUS(rirq);
	function = REAL_IRQ_TO_FUNC(rirq);
	dev_id = (REAL_IRQ_TO_IDSEL(rirq) << 4) + function;

	/* Mask secondary INTA */
	mask = 0x80000000;
	HvCallPci_maskInterrupts(bus, sub_bus, dev_id, mask);
	}

	static void iseries_end_IRQ(struct irq_data *d)
	{
	unsigned int rirq = (unsigned int)irqd_to_hwirq(d);

	HvCallPci_eoi(REAL_IRQ_TO_BUS(rirq), REAL_IRQ_TO_SUBBUS(rirq),
	(REAL_IRQ_TO_IDSEL(rirq) << 4) + REAL_IRQ_TO_FUNC(rirq));
	}

	static struct irq_chip iseries_pic = {
	.name = "iSeries",
	.irq_startup = iseries_startup_IRQ,
	.irq_shutdown = iseries_shutdown_IRQ,
	.irq_unmask = iseries_enable_IRQ,
	.irq_mask = iseries_disable_IRQ,
	.irq_eoi = iseries_end_IRQ
	};

	/*
	* This is called out of iSeries_scan_slot to allocate an IRQ for an EADS slot
	* It calculates the irq value for the slot.
	* Note that sub_bus is always 0 (at the moment at least).
	*/
	int __init iSeries_allocate_IRQ(HvBusNumber bus,
	HvSubBusNumber sub_bus, u32 bsubbus)
	{
	unsigned int realirq;
	u8 idsel = ISERIES_GET_DEVICE_FROM_SUBBUS(bsubbus);
	u8 function = ISERIES_GET_FUNCTION_FROM_SUBBUS(bsubbus);

	realirq = (((((sub_bus << 8) + (bus - 1)) << 3) + (idsel - 1)) << 3)
	+ function;

	return irq_create_mapping(NULL, realirq);
	}

	#endif /* CONFIG_PCI */

	/*
	* Get the next pending IRQ.
	*/
	unsigned int iSeries_get_irq(void)
	{
	int irq = NO_IRQ_IGNORE;

	#ifdef CONFIG_SMP
	if (get_lppaca()->int_dword.fields.ipi_cnt) {
	get_lppaca()->int_dword.fields.ipi_cnt = 0;
	smp_ipi_demux();
	}
	#endif /* CONFIG_SMP */
	if (hvlpevent_is_pending())
	process_hvlpevents();

	#ifdef CONFIG_PCI
	if (num_pending_irqs) {
	spin_lock(&pending_irqs_lock);
	for (irq = 0; irq < NR_IRQS; irq++) {
	if (pending_irqs[irq]) {
	pending_irqs[irq]--;
	num_pending_irqs--;
	break;
	}
	}
	spin_unlock(&pending_irqs_lock);
	if (irq >= NR_IRQS)
	irq = NO_IRQ_IGNORE;
	}
	#endif

	return irq;
	}

	#ifdef CONFIG_PCI

	static int iseries_irq_host_map(struct irq_host *h, unsigned int virq,
	irq_hw_number_t hw)
	{
	irq_set_chip_and_handler(virq, &iseries_pic, handle_fasteoi_irq);

	return 0;
	}

	static int iseries_irq_host_match(struct irq_host h, struct device_node np)
	{
	/* Match all */
	return 1;
	}

	static struct irq_host_ops iseries_irq_host_ops = {
	.map = iseries_irq_host_map,
	.match = iseries_irq_host_match,
	};

	/*
	* This is called by init_IRQ. set in ppc_md.init_IRQ by iSeries_setup.c
	* It must be called before the bus walk.
	*/
	void __init iSeries_init_IRQ(void)
	{
	/* Register PCI event handler and open an event path */
	struct irq_host *host;
	int ret;

	/*
	* The Hypervisor only allows us up to 256 interrupt
	* sources (the irq number is passed in a u8).
	*/
	irq_set_virq_count(256);

	/* Create irq host. No need for a revmap since HV will give us
	* back our virtual irq number
	*/
	host = irq_alloc_host(NULL, IRQ_HOST_MAP_NOMAP, 0,
	&iseries_irq_host_ops, 0);
	BUG_ON(host == NULL);
	irq_set_default_host(host);

	ret = HvLpEvent_registerHandler(HvLpEvent_Type_PciIo,
	&pci_event_handler);
	if (ret == 0) {
	ret = HvLpEvent_openPath(HvLpEvent_Type_PciIo, 0);
	if (ret != 0)
	printk(KERN_ERR "iseries_init_IRQ: open event path "
	"failed with rc 0x%x\n", ret);
	} else
	printk(KERN_ERR "iseries_init_IRQ: register handler "
	"failed with rc 0x%x\n", ret);
	}

	#endif /* CONFIG_PCI */