arch/ppc/syslib/open_pic.c

/*
 *  arch/ppc/kernel/open_pic.c -- OpenPIC Interrupt Handling
 *
 *  Copyright (C) 1997 Geert Uytterhoeven
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License.  See the file COPYING in the main directory of this archive
 *  for more details.
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/sysdev.h>
#include <linux/errno.h>
#include <asm/ptrace.h>
#include <asm/signal.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/sections.h>
#include <asm/open_pic.h>
#include <asm/i8259.h>

#include "open_pic_defs.h"

#if defined(CONFIG_PRPMC800) || defined(CONFIG_85xx)
#define OPENPIC_BIG_ENDIAN
#endif

void __iomem *OpenPIC_Addr;
static volatile struct OpenPIC __iomem *OpenPIC = NULL;

/*
 * We define OpenPIC_InitSenses table thusly:
 * bit 0x1: sense, 0 for edge and 1 for level.
 * bit 0x2: polarity, 0 for negative, 1 for positive.
 */
u_int OpenPIC_NumInitSenses __initdata = 0;
u_char *OpenPIC_InitSenses __initdata = NULL;
extern int use_of_interrupt_tree;

static u_int NumProcessors;
static u_int NumSources;
static int open_pic_irq_offset;
static volatile OpenPIC_Source __iomem *ISR[NR_IRQS];
static int openpic_cascade_irq = -1;
static int (*openpic_cascade_fn)(struct pt_regs *);

/* Global Operations */
static void openpic_disable_8259_pass_through(void);
static void openpic_set_spurious(u_int vector);

#ifdef CONFIG_SMP
/* Interprocessor Interrupts */
static void openpic_initipi(u_int ipi, u_int pri, u_int vector);
static irqreturn_t openpic_ipi_action(int cpl, void *dev_id, struct pt_regs *);
#endif

/* Timer Interrupts */
static void openpic_inittimer(u_int timer, u_int pri, u_int vector);
static void openpic_maptimer(u_int timer, cpumask_t cpumask);

/* Interrupt Sources */
static void openpic_enable_irq(u_int irq);
static void openpic_disable_irq(u_int irq);
static void openpic_initirq(u_int irq, u_int pri, u_int vector, int polarity,
			    int is_level);
static void openpic_mapirq(u_int irq, cpumask_t cpumask, cpumask_t keepmask);

/*
 * These functions are not used but the code is kept here
 * for completeness and future reference.
 */
#ifdef notused
static void openpic_enable_8259_pass_through(void);
static u_int openpic_get_spurious(void);
static void openpic_set_sense(u_int irq, int sense);
#endif /* notused */

/*
 * Description of the openpic for the higher-level irq code
 */
static void openpic_end_irq(unsigned int irq_nr);
static void openpic_ack_irq(unsigned int irq_nr);
static void openpic_set_affinity(unsigned int irq_nr, cpumask_t cpumask);

struct hw_interrupt_type open_pic = {
	.typename	= " OpenPIC  ",
	.enable		= openpic_enable_irq,
	.disable	= openpic_disable_irq,
	.ack		= openpic_ack_irq,
	.end		= openpic_end_irq,
	.set_affinity	= openpic_set_affinity,
};

#ifdef CONFIG_SMP
static void openpic_end_ipi(unsigned int irq_nr);
static void openpic_ack_ipi(unsigned int irq_nr);
static void openpic_enable_ipi(unsigned int irq_nr);
static void openpic_disable_ipi(unsigned int irq_nr);

struct hw_interrupt_type open_pic_ipi = {
	.typename	= " OpenPIC  ",
	.enable		= openpic_enable_ipi,
	.disable	= openpic_disable_ipi,
	.ack		= openpic_ack_ipi,
	.end		= openpic_end_ipi,
};
#endif /* CONFIG_SMP */

/*
 *  Accesses to the current processor's openpic registers
 */
#ifdef CONFIG_SMP
#define THIS_CPU		Processor[cpu]
#define DECL_THIS_CPU		int cpu = smp_hw_index[smp_processor_id()]
#define CHECK_THIS_CPU		check_arg_cpu(cpu)
#else
#define THIS_CPU		Processor[0]
#define DECL_THIS_CPU
#define CHECK_THIS_CPU
#endif /* CONFIG_SMP */

#if 1
#define check_arg_ipi(ipi) \
    if (ipi < 0 || ipi >= OPENPIC_NUM_IPI) \
	printk("open_pic.c:%d: invalid ipi %d\n", __LINE__, ipi);
#define check_arg_timer(timer) \
    if (timer < 0 || timer >= OPENPIC_NUM_TIMERS) \
	printk("open_pic.c:%d: invalid timer %d\n", __LINE__, timer);
#define check_arg_vec(vec) \
    if (vec < 0 || vec >= OPENPIC_NUM_VECTORS) \
	printk("open_pic.c:%d: invalid vector %d\n", __LINE__, vec);
#define check_arg_pri(pri) \
    if (pri < 0 || pri >= OPENPIC_NUM_PRI) \
	printk("open_pic.c:%d: invalid priority %d\n", __LINE__, pri);
/*
 * Print out a backtrace if it's out of range, since if it's larger than NR_IRQ's
 * data has probably been corrupted and we're going to panic or deadlock later
 * anyway --Troy
 */
#define check_arg_irq(irq) \
    if (irq < open_pic_irq_offset || irq >= NumSources+open_pic_irq_offset \
	|| ISR[irq - open_pic_irq_offset] == 0) { \
      printk("open_pic.c:%d: invalid irq %d\n", __LINE__, irq); \
      dump_stack(); }
#define check_arg_cpu(cpu) \
    if (cpu < 0 || cpu >= NumProcessors){ \
	printk("open_pic.c:%d: invalid cpu %d\n", __LINE__, cpu); \
	dump_stack(); }
#else
#define check_arg_ipi(ipi)	do {} while (0)
#define check_arg_timer(timer)	do {} while (0)
#define check_arg_vec(vec)	do {} while (0)
#define check_arg_pri(pri)	do {} while (0)
#define check_arg_irq(irq)	do {} while (0)
#define check_arg_cpu(cpu)	do {} while (0)
#endif

u_int openpic_read(volatile u_int __iomem *addr)
{
	u_int val;

#ifdef OPENPIC_BIG_ENDIAN
	val = in_be32(addr);
#else
	val = in_le32(addr);
#endif
	return val;
}

static inline void openpic_write(volatile u_int __iomem *addr, u_int val)
{
#ifdef OPENPIC_BIG_ENDIAN
	out_be32(addr, val);
#else
	out_le32(addr, val);
#endif
}

static inline u_int openpic_readfield(volatile u_int __iomem *addr, u_int mask)
{
	u_int val = openpic_read(addr);
	return val & mask;
}

inline void openpic_writefield(volatile u_int __iomem *addr, u_int mask,
			       u_int field)
{
	u_int val = openpic_read(addr);
	openpic_write(addr, (val & ~mask) | (field & mask));
}

static inline void openpic_clearfield(volatile u_int __iomem *addr, u_int mask)
{
	openpic_writefield(addr, mask, 0);
}

static inline void openpic_setfield(volatile u_int __iomem *addr, u_int mask)
{
	openpic_writefield(addr, mask, mask);
}

static void openpic_safe_writefield(volatile u_int __iomem *addr, u_int mask,
				    u_int field)
{
	openpic_setfield(addr, OPENPIC_MASK);
	while (openpic_read(addr) & OPENPIC_ACTIVITY);
	openpic_writefield(addr, mask | OPENPIC_MASK, field | OPENPIC_MASK);
}

#ifdef CONFIG_SMP
/* yes this is right ... bug, feature, you decide! -- tgall */
u_int openpic_read_IPI(volatile u_int __iomem * addr)
{
         u_int val = 0;
#if defined(OPENPIC_BIG_ENDIAN) || defined(CONFIG_POWER3)
        val = in_be32(addr);
#else
        val = in_le32(addr);
#endif
        return val;
}

/* because of the power3 be / le above, this is needed */
inline void openpic_writefield_IPI(volatile u_int __iomem * addr, u_int mask, u_int field)
{
        u_int  val = openpic_read_IPI(addr);
        openpic_write(addr, (val & ~mask) | (field & mask));
}

static inline void openpic_clearfield_IPI(volatile u_int __iomem *addr, u_int mask)
{
        openpic_writefield_IPI(addr, mask, 0);
}

static inline void openpic_setfield_IPI(volatile u_int __iomem *addr, u_int mask)
{
        openpic_writefield_IPI(addr, mask, mask);
}

static void openpic_safe_writefield_IPI(volatile u_int __iomem *addr, u_int mask, u_int field)
{
        openpic_setfield_IPI(addr, OPENPIC_MASK);

        /* wait until it's not in use */
        /* BenH: Is this code really enough ? I would rather check the result
         *       and eventually retry ...
         */
        while(openpic_read_IPI(addr) & OPENPIC_ACTIVITY);

        openpic_writefield_IPI(addr, mask | OPENPIC_MASK, field | OPENPIC_MASK);
}
#endif /* CONFIG_SMP */

#ifdef CONFIG_EPIC_SERIAL_MODE
/* On platforms that may use EPIC serial mode, the default is enabled. */
int epic_serial_mode = 1;

static void __init openpic_eicr_set_clk(u_int clkval)
{
	openpic_writefield(&OpenPIC->Global.Global_Configuration1,
			OPENPIC_EICR_S_CLK_MASK, (clkval << 28));
}

static void __init openpic_enable_sie(void)
{
	openpic_setfield(&OpenPIC->Global.Global_Configuration1,
			OPENPIC_EICR_SIE);
}
#endif

#if defined(CONFIG_EPIC_SERIAL_MODE)
static void openpic_reset(void)
{
	openpic_setfield(&OpenPIC->Global.Global_Configuration0,
			 OPENPIC_CONFIG_RESET);
	while (openpic_readfield(&OpenPIC->Global.Global_Configuration0,
				 OPENPIC_CONFIG_RESET))
		mb();
}
#endif

void __init openpic_set_sources(int first_irq, int num_irqs, void __iomem *first_ISR)
{
	volatile OpenPIC_Source __iomem *src = first_ISR;
	int i, last_irq;

	last_irq = first_irq + num_irqs;
	if (last_irq > NumSources)
		NumSources = last_irq;
	if (src == 0)
		src = &((struct OpenPIC __iomem *)OpenPIC_Addr)->Source[first_irq];
	for (i = first_irq; i < last_irq; ++i, ++src)
		ISR[i] = src;
}

/*
 * The `offset' parameter defines where the interrupts handled by the
 * OpenPIC start in the space of interrupt numbers that the kernel knows
 * about.  In other words, the OpenPIC's IRQ0 is numbered `offset' in the
 * kernel's interrupt numbering scheme.
 * We assume there is only one OpenPIC.
 */
void __init openpic_init(int offset)
{
	u_int t, i;
	u_int timerfreq;
	const char *version;

	if (!OpenPIC_Addr) {
		printk("No OpenPIC found !\n");
		return;
	}
	OpenPIC = (volatile struct OpenPIC __iomem *)OpenPIC_Addr;

#ifdef CONFIG_EPIC_SERIAL_MODE
	/* Have to start from ground zero.
	*/
	openpic_reset();
#endif

	if (ppc_md.progress) ppc_md.progress("openpic: enter", 0x122);

	t = openpic_read(&OpenPIC->Global.Feature_Reporting0);
	switch (t & OPENPIC_FEATURE_VERSION_MASK) {
	case 1:
		version = "1.0";
		break;
	case 2:
		version = "1.2";
		break;
	case 3:
		version = "1.3";
		break;
	default:
		version = "?";
		break;
	}
	NumProcessors = ((t & OPENPIC_FEATURE_LAST_PROCESSOR_MASK) >>
			 OPENPIC_FEATURE_LAST_PROCESSOR_SHIFT) + 1;
	if (NumSources == 0)
		openpic_set_sources(0,
				    ((t & OPENPIC_FEATURE_LAST_SOURCE_MASK) >>
				     OPENPIC_FEATURE_LAST_SOURCE_SHIFT) + 1,
				    NULL);
	printk("OpenPIC Version %s (%d CPUs and %d IRQ sources) at %p\n",
	       version, NumProcessors, NumSources, OpenPIC);
	timerfreq = openpic_read(&OpenPIC->Global.Timer_Frequency);
	if (timerfreq)
		printk("OpenPIC timer frequency is %d.%06d MHz\n",
		       timerfreq / 1000000, timerfreq % 1000000);

	open_pic_irq_offset = offset;

	/* Initialize timer interrupts */
	if ( ppc_md.progress ) ppc_md.progress("openpic: timer",0x3ba);
	for (i = 0; i < OPENPIC_NUM_TIMERS; i++) {
		/* Disabled, Priority 0 */
		openpic_inittimer(i, 0, OPENPIC_VEC_TIMER+i+offset);
		/* No processor */
		openpic_maptimer(i, CPU_MASK_NONE);
	}

#ifdef CONFIG_SMP
	/* Initialize IPI interrupts */
	if ( ppc_md.progress ) ppc_md.progress("openpic: ipi",0x3bb);
	for (i = 0; i < OPENPIC_NUM_IPI; i++) {
		/* Disabled, increased priorities 10..13 */
		openpic_initipi(i, OPENPIC_PRIORITY_IPI_BASE+i,
				OPENPIC_VEC_IPI+i+offset);
		/* IPIs are per-CPU */
		irq_desc[OPENPIC_VEC_IPI+i+offset].status |= IRQ_PER_CPU;
		irq_desc[OPENPIC_VEC_IPI+i+offset].handler = &open_pic_ipi;
	}
#endif

	/* Initialize external interrupts */
	if (ppc_md.progress) ppc_md.progress("openpic: external",0x3bc);

	openpic_set_priority(0xf);

	/* Init all external sources, including possibly the cascade. */
	for (i = 0; i < NumSources; i++) {
		int sense;

		if (ISR[i] == 0)
			continue;

		/* the bootloader may have left it enabled (bad !) */
		openpic_disable_irq(i+offset);

		sense = (i < OpenPIC_NumInitSenses)? OpenPIC_InitSenses[i]: \
				(IRQ_SENSE_LEVEL | IRQ_POLARITY_NEGATIVE);

		if (sense & IRQ_SENSE_MASK)
			irq_desc[i+offset].status = IRQ_LEVEL;

		/* Enabled, Default priority */
		openpic_initirq(i, OPENPIC_PRIORITY_DEFAULT, i+offset,
				(sense & IRQ_POLARITY_MASK),
				(sense & IRQ_SENSE_MASK));
		/* Processor 0 */
		openpic_mapirq(i, CPU_MASK_CPU0, CPU_MASK_NONE);
	}

	/* Init descriptors */
	for (i = offset; i < NumSources + offset; i++)
		irq_desc[i].handler = &open_pic;

	/* Initialize the spurious interrupt */
	if (ppc_md.progress) ppc_md.progress("openpic: spurious",0x3bd);
	openpic_set_spurious(OPENPIC_VEC_SPURIOUS);
	openpic_disable_8259_pass_through();
#ifdef CONFIG_EPIC_SERIAL_MODE
	if (epic_serial_mode) {
		openpic_eicr_set_clk(7);	/* Slowest value until we know better */
		openpic_enable_sie();
	}
#endif
	openpic_set_priority(0);

	if (ppc_md.progress) ppc_md.progress("openpic: exit",0x222);
}

#ifdef notused
static void openpic_enable_8259_pass_through(void)
{
	openpic_clearfield(&OpenPIC->Global.Global_Configuration0,
			   OPENPIC_CONFIG_8259_PASSTHROUGH_DISABLE);
}
#endif /* notused */

static void openpic_disable_8259_pass_through(void)
{
	openpic_setfield(&OpenPIC->Global.Global_Configuration0,
			 OPENPIC_CONFIG_8259_PASSTHROUGH_DISABLE);
}

/*
 *  Find out the current interrupt
 */
u_int openpic_irq(void)
{
	u_int vec;
	DECL_THIS_CPU;

	CHECK_THIS_CPU;
	vec = openpic_readfield(&OpenPIC->THIS_CPU.Interrupt_Acknowledge,
				OPENPIC_VECTOR_MASK);
	return vec;
}

void openpic_eoi(void)
{
	DECL_THIS_CPU;

	CHECK_THIS_CPU;
	openpic_write(&OpenPIC->THIS_CPU.EOI, 0);
	/* Handle PCI write posting */
	(void)openpic_read(&OpenPIC->THIS_CPU.EOI);
}

u_int openpic_get_priority(void)
{
	DECL_THIS_CPU;

	CHECK_THIS_CPU;
	return openpic_readfield(&OpenPIC->THIS_CPU.Current_Task_Priority,
				 OPENPIC_CURRENT_TASK_PRIORITY_MASK);
}

void openpic_set_priority(u_int pri)
{
	DECL_THIS_CPU;

	CHECK_THIS_CPU;
	check_arg_pri(pri);
	openpic_writefield(&OpenPIC->THIS_CPU.Current_Task_Priority,
			   OPENPIC_CURRENT_TASK_PRIORITY_MASK, pri);
}

/*
 *  Get/set the spurious vector
 */
#ifdef notused
static u_int openpic_get_spurious(void)
{
	return openpic_readfield(&OpenPIC->Global.Spurious_Vector,
				 OPENPIC_VECTOR_MASK);
}
#endif /* notused */

static void openpic_set_spurious(u_int vec)
{
	check_arg_vec(vec);
	openpic_writefield(&OpenPIC->Global.Spurious_Vector, OPENPIC_VECTOR_MASK,
			   vec);
}

#ifdef CONFIG_SMP
/*
 * Convert a cpu mask from logical to physical cpu numbers.
 */
static inline cpumask_t physmask(cpumask_t cpumask)
{
	int i;
	cpumask_t mask = CPU_MASK_NONE;

	cpus_and(cpumask, cpu_online_map, cpumask);

	for (i = 0; i < NR_CPUS; i++)
		if (cpu_isset(i, cpumask))
			cpu_set(smp_hw_index[i], mask);

	return mask;
}
#else
#define physmask(cpumask)	(cpumask)
#endif

void openpic_reset_processor_phys(u_int mask)
{
	openpic_write(&OpenPIC->Global.Processor_Initialization, mask);
}

#if defined(CONFIG_SMP) || defined(CONFIG_PM)
static DEFINE_SPINLOCK(openpic_setup_lock);
#endif

#ifdef CONFIG_SMP
/*
 *  Initialize an interprocessor interrupt (and disable it)
 *
 *  ipi: OpenPIC interprocessor interrupt number
 *  pri: interrupt source priority
 *  vec: the vector it will produce
 */
static void __init openpic_initipi(u_int ipi, u_int pri, u_int vec)
{
	check_arg_ipi(ipi);
	check_arg_pri(pri);
	check_arg_vec(vec);
	openpic_safe_writefield_IPI(&OpenPIC->Global.IPI_Vector_Priority(ipi),
				OPENPIC_PRIORITY_MASK | OPENPIC_VECTOR_MASK,
				(pri << OPENPIC_PRIORITY_SHIFT) | vec);
}

/*
 *  Send an IPI to one or more CPUs
 *
 *  Externally called, however, it takes an IPI number (0...OPENPIC_NUM_IPI)
 *  and not a system-wide interrupt number
 */
void openpic_cause_IPI(u_int ipi, cpumask_t cpumask)
{
	DECL_THIS_CPU;

	CHECK_THIS_CPU;
	check_arg_ipi(ipi);
	openpic_write(&OpenPIC->THIS_CPU.IPI_Dispatch(ipi),
		      cpus_addr(physmask(cpumask))[0]);
}

void openpic_request_IPIs(void)
{
	int i;

	/*
	 * Make sure this matches what is defined in smp.c for
	 * smp_message_{pass|recv}() or what shows up in
	 * /proc/interrupts will be wrong!!! --Troy */

	if (OpenPIC == NULL)
		return;

	/* IPIs are marked SA_INTERRUPT as they must run with irqs disabled */
	request_irq(OPENPIC_VEC_IPI+open_pic_irq_offset,
		    openpic_ipi_action, SA_INTERRUPT,
		    "IPI0 (call function)", NULL);
	request_irq(OPENPIC_VEC_IPI+open_pic_irq_offset+1,
		    openpic_ipi_action, SA_INTERRUPT,
		    "IPI1 (reschedule)", NULL);
	request_irq(OPENPIC_VEC_IPI+open_pic_irq_offset+2,
		    openpic_ipi_action, SA_INTERRUPT,
		    "IPI2 (invalidate tlb)", NULL);
	request_irq(OPENPIC_VEC_IPI+open_pic_irq_offset+3,
		    openpic_ipi_action, SA_INTERRUPT,
		    "IPI3 (xmon break)", NULL);

	for ( i = 0; i < OPENPIC_NUM_IPI ; i++ )
		openpic_enable_ipi(OPENPIC_VEC_IPI+open_pic_irq_offset+i);
}

/*
 * Do per-cpu setup for SMP systems.
 *
 * Get IPI's working and start taking interrupts.
 *   -- Cort
 */

void __devinit do_openpic_setup_cpu(void)
{
#ifdef CONFIG_IRQ_ALL_CPUS
 	int i;
	cpumask_t msk = CPU_MASK_NONE;
#endif
	spin_lock(&openpic_setup_lock);

#ifdef CONFIG_IRQ_ALL_CPUS
	cpu_set(smp_hw_index[smp_processor_id()], msk);

 	/* let the openpic know we want intrs. default affinity
 	 * is 0xffffffff until changed via /proc
 	 * That's how it's done on x86. If we want it differently, then
 	 * we should make sure we also change the default values of irq_affinity
 	 * in irq.c.
 	 */
 	for (i = 0; i < NumSources; i++)
		openpic_mapirq(i, msk, CPU_MASK_ALL);
#endif /* CONFIG_IRQ_ALL_CPUS */
 	openpic_set_priority(0);

	spin_unlock(&openpic_setup_lock);
}
#endif /* CONFIG_SMP */

/*
 *  Initialize a timer interrupt (and disable it)
 *
 *  timer: OpenPIC timer number
 *  pri: interrupt source priority
 *  vec: the vector it will produce
 */
static void __init openpic_inittimer(u_int timer, u_int pri, u_int vec)
{
	check_arg_timer(timer);
	check_arg_pri(pri);
	check_arg_vec(vec);
	openpic_safe_writefield(&OpenPIC->Global.Timer[timer].Vector_Priority,
				OPENPIC_PRIORITY_MASK | OPENPIC_VECTOR_MASK,
				(pri << OPENPIC_PRIORITY_SHIFT) | vec);
}

/*
 *  Map a timer interrupt to one or more CPUs
 */
static void __init openpic_maptimer(u_int timer, cpumask_t cpumask)
{
	cpumask_t phys = physmask(cpumask);
	check_arg_timer(timer);
	openpic_write(&OpenPIC->Global.Timer[timer].Destination,
		      cpus_addr(phys)[0]);
}

/*
 * Change the priority of an interrupt
 */
void __init
openpic_set_irq_priority(u_int irq, u_int pri)
{
	check_arg_irq(irq);
	openpic_safe_writefield(&ISR[irq - open_pic_irq_offset]->Vector_Priority,
				OPENPIC_PRIORITY_MASK,
				pri << OPENPIC_PRIORITY_SHIFT);
}

/*
 * Initalize the interrupt source which will generate an NMI.
 * This raises the interrupt's priority from 8 to 9.
 *
 * irq: The logical IRQ which generates an NMI.
 */
void __init
openpic_init_nmi_irq(u_int irq)
{
	check_arg_irq(irq);
	openpic_set_irq_priority(irq, OPENPIC_PRIORITY_NMI);
}

/*
 *
 * All functions below take an offset'ed irq argument
 *
 */

/*
 * Hookup a cascade to the OpenPIC.
 */

static struct irqaction openpic_cascade_irqaction = {
	.handler = no_action,
	.flags = SA_INTERRUPT,
	.mask = CPU_MASK_NONE,
};

void __init
openpic_hookup_cascade(u_int irq, char *name,
	int (*cascade_fn)(struct pt_regs *))
{
	openpic_cascade_irq = irq;
	openpic_cascade_fn = cascade_fn;

	if (setup_irq(irq, &openpic_cascade_irqaction))
		printk("Unable to get OpenPIC IRQ %d for cascade\n",
				irq - open_pic_irq_offset);
}

/*
 *  Enable/disable an external interrupt source
 *
 *  Externally called, irq is an offseted system-wide interrupt number
 */
static void openpic_enable_irq(u_int irq)
{
	volatile u_int __iomem *vpp;

	check_arg_irq(irq);
	vpp = &ISR[irq - open_pic_irq_offset]->Vector_Priority;
	openpic_clearfield(vpp, OPENPIC_MASK);
	/* make sure mask gets to controller before we return to user */
	do {
		mb(); /* sync is probably useless here */
	} while (openpic_readfield(vpp, OPENPIC_MASK));
}

static void openpic_disable_irq(u_int irq)
{
	volatile u_int __iomem *vpp;
	u32 vp;

	check_arg_irq(irq);
	vpp = &ISR[irq - open_pic_irq_offset]->Vector_Priority;
	openpic_setfield(vpp, OPENPIC_MASK);
	/* make sure mask gets to controller before we return to user */
	do {
		mb();  /* sync is probably useless here */
		vp = openpic_readfield(vpp, OPENPIC_MASK | OPENPIC_ACTIVITY);
	} while((vp & OPENPIC_ACTIVITY) && !(vp & OPENPIC_MASK));
}

#ifdef CONFIG_SMP
/*
 *  Enable/disable an IPI interrupt source
 *
 *  Externally called, irq is an offseted system-wide interrupt number
 */
void openpic_enable_ipi(u_int irq)
{
	irq -= (OPENPIC_VEC_IPI+open_pic_irq_offset);
	check_arg_ipi(irq);
	openpic_clearfield_IPI(&OpenPIC->Global.IPI_Vector_Priority(irq), OPENPIC_MASK);

}

void openpic_disable_ipi(u_int irq)
{
	irq -= (OPENPIC_VEC_IPI+open_pic_irq_offset);
	check_arg_ipi(irq);
	openpic_setfield_IPI(&OpenPIC->Global.IPI_Vector_Priority(irq), OPENPIC_MASK);
}
#endif

/*
 *  Initialize an interrupt source (and disable it!)
 *
 *  irq: OpenPIC interrupt number
 *  pri: interrupt source priority
 *  vec: the vector it will produce
 *  pol: polarity (1 for positive, 0 for negative)
 *  sense: 1 for level, 0 for edge
 */
static void __init
openpic_initirq(u_int irq, u_int pri, u_int vec, int pol, int sense)
{
	openpic_safe_writefield(&ISR[irq]->Vector_Priority,
				OPENPIC_PRIORITY_MASK | OPENPIC_VECTOR_MASK |
				OPENPIC_SENSE_MASK | OPENPIC_POLARITY_MASK,
				(pri << OPENPIC_PRIORITY_SHIFT) | vec |
				(pol ? OPENPIC_POLARITY_POSITIVE :
			    		OPENPIC_POLARITY_NEGATIVE) |
				(sense ? OPENPIC_SENSE_LEVEL : OPENPIC_SENSE_EDGE));
}

/*
 *  Map an interrupt source to one or more CPUs
 */
static void openpic_mapirq(u_int irq, cpumask_t physmask, cpumask_t keepmask)
{
	if (ISR[irq] == 0)
		return;
	if (!cpus_empty(keepmask)) {
		cpumask_t irqdest = { .bits[0] = openpic_read(&ISR[irq]->Destination) };
		cpus_and(irqdest, irqdest, keepmask);
		cpus_or(physmask, physmask, irqdest);
	}
	openpic_write(&ISR[irq]->Destination, cpus_addr(physmask)[0]);
}

#ifdef notused
/*
 *  Set the sense for an interrupt source (and disable it!)
 *
 *  sense: 1 for level, 0 for edge
 */
static void openpic_set_sense(u_int irq, int sense)
{
	if (ISR[irq] != 0)
		openpic_safe_writefield(&ISR[irq]->Vector_Priority,
					OPENPIC_SENSE_LEVEL,
					(sense ? OPENPIC_SENSE_LEVEL : 0));
}
#endif /* notused */

/* No spinlocks, should not be necessary with the OpenPIC
 * (1 register = 1 interrupt and we have the desc lock).
 */
static void openpic_ack_irq(unsigned int irq_nr)
{
#ifdef __SLOW_VERSION__
	openpic_disable_irq(irq_nr);
	openpic_eoi();
#else
	if ((irq_desc[irq_nr].status & IRQ_LEVEL) == 0)
		openpic_eoi();
#endif
}

static void openpic_end_irq(unsigned int irq_nr)
{
#ifdef __SLOW_VERSION__
	if (!(irq_desc[irq_nr].status & (IRQ_DISABLED|IRQ_INPROGRESS))
	    && irq_desc[irq_nr].action)
		openpic_enable_irq(irq_nr);
#else
	if ((irq_desc[irq_nr].status & IRQ_LEVEL) != 0)
		openpic_eoi();
#endif
}

static void openpic_set_affinity(unsigned int irq_nr, cpumask_t cpumask)
{
	openpic_mapirq(irq_nr - open_pic_irq_offset, physmask(cpumask), CPU_MASK_NONE);
}

#ifdef CONFIG_SMP
static void openpic_ack_ipi(unsigned int irq_nr)
{
	openpic_eoi();
}

static void openpic_end_ipi(unsigned int irq_nr)
{
}

static irqreturn_t openpic_ipi_action(int cpl, void *dev_id, struct pt_regs *regs)
{
	smp_message_recv(cpl-OPENPIC_VEC_IPI-open_pic_irq_offset, regs);
	return IRQ_HANDLED;
}

#endif /* CONFIG_SMP */

int
openpic_get_irq(struct pt_regs *regs)
{
	int irq = openpic_irq();

	/*
	 * Check for the cascade interrupt and call the cascaded
	 * interrupt controller function (usually i8259_irq) if so.
	 * This should move to irq.c eventually.  -- paulus
	 */
	if (irq == openpic_cascade_irq && openpic_cascade_fn != NULL) {
		int cirq = openpic_cascade_fn(regs);

		/* Allow for the cascade being shared with other devices */
		if (cirq != -1) {
			irq = cirq;
			openpic_eoi();
		}
	} else if (irq == OPENPIC_VEC_SPURIOUS)
		irq = -1;
	return irq;
}

#ifdef CONFIG_SMP
void
smp_openpic_message_pass(int target, int msg, unsigned long data, int wait)
{
	cpumask_t mask = CPU_MASK_ALL;
	/* make sure we're sending something that translates to an IPI */
	if (msg > 0x3) {
		printk("SMP %d: smp_message_pass: unknown msg %d\n",
		       smp_processor_id(), msg);
		return;
	}
	switch (target) {
	case MSG_ALL:
		openpic_cause_IPI(msg, mask);
		break;
	case MSG_ALL_BUT_SELF:
		cpu_clear(smp_processor_id(), mask);
		openpic_cause_IPI(msg, mask);
		break;
	default:
		openpic_cause_IPI(msg, cpumask_of_cpu(target));
		break;
	}
}
#endif /* CONFIG_SMP */

#ifdef CONFIG_PM

/*
 * We implement the IRQ controller as a sysdev and put it
 * to sleep at powerdown stage (the callback is named suspend,
 * but it's old semantics, for the Device Model, it's really
 * powerdown). The possible problem is that another sysdev that
 * happens to be suspend after this one will have interrupts off,
 * that may be an issue... For now, this isn't an issue on pmac
 * though...
 */

static u32 save_ipi_vp[OPENPIC_NUM_IPI];
static u32 save_irq_src_vp[OPENPIC_MAX_SOURCES];
static u32 save_irq_src_dest[OPENPIC_MAX_SOURCES];
static u32 save_cpu_task_pri[OPENPIC_MAX_PROCESSORS];
static int openpic_suspend_count;

static void openpic_cached_enable_irq(u_int irq)
{
	check_arg_irq(irq);
	save_irq_src_vp[irq - open_pic_irq_offset] &= ~OPENPIC_MASK;
}

static void openpic_cached_disable_irq(u_int irq)
{
	check_arg_irq(irq);
	save_irq_src_vp[irq - open_pic_irq_offset] |= OPENPIC_MASK;
}

/* WARNING: Can be called directly by the cpufreq code with NULL parameter,
 * we need something better to deal with that... Maybe switch to S1 for
 * cpufreq changes
 */
int openpic_suspend(struct sys_device *sysdev, u32 state)
{
	int	i;
	unsigned long flags;

	spin_lock_irqsave(&openpic_setup_lock, flags);

	if (openpic_suspend_count++ > 0) {
		spin_unlock_irqrestore(&openpic_setup_lock, flags);
		return 0;
	}

 	openpic_set_priority(0xf);

	open_pic.enable = openpic_cached_enable_irq;
	open_pic.disable = openpic_cached_disable_irq;

	for (i=0; i<NumProcessors; i++) {
		save_cpu_task_pri[i] = openpic_read(&OpenPIC->Processor[i].Current_Task_Priority);
		openpic_writefield(&OpenPIC->Processor[i].Current_Task_Priority,
				   OPENPIC_CURRENT_TASK_PRIORITY_MASK, 0xf);
	}

	for (i=0; i<OPENPIC_NUM_IPI; i++)
		save_ipi_vp[i] = openpic_read(&OpenPIC->Global.IPI_Vector_Priority(i));
	for (i=0; i<NumSources; i++) {
		if (ISR[i] == 0)
			continue;
		save_irq_src_vp[i] = openpic_read(&ISR[i]->Vector_Priority) & ~OPENPIC_ACTIVITY;
		save_irq_src_dest[i] = openpic_read(&ISR[i]->Destination);
	}

	spin_unlock_irqrestore(&openpic_setup_lock, flags);

	return 0;
}

/* WARNING: Can be called directly by the cpufreq code with NULL parameter,
 * we need something better to deal with that... Maybe switch to S1 for
 * cpufreq changes
 */
int openpic_resume(struct sys_device *sysdev)
{
	int		i;
	unsigned long	flags;
	u32		vppmask =	OPENPIC_PRIORITY_MASK | OPENPIC_VECTOR_MASK |
					OPENPIC_SENSE_MASK | OPENPIC_POLARITY_MASK |
					OPENPIC_MASK;

	spin_lock_irqsave(&openpic_setup_lock, flags);

	if ((--openpic_suspend_count) > 0) {
		spin_unlock_irqrestore(&openpic_setup_lock, flags);
		return 0;
	}

	/* OpenPIC sometimes seem to need some time to be fully back up... */
	do {
		openpic_set_spurious(OPENPIC_VEC_SPURIOUS);
	} while(openpic_readfield(&OpenPIC->Global.Spurious_Vector, OPENPIC_VECTOR_MASK)
			!= OPENPIC_VEC_SPURIOUS);
	
	openpic_disable_8259_pass_through();

	for (i=0; i<OPENPIC_NUM_IPI; i++)
		openpic_write(&OpenPIC->Global.IPI_Vector_Priority(i),
			      save_ipi_vp[i]);
	for (i=0; i<NumSources; i++) {
		if (ISR[i] == 0)
			continue;
		openpic_write(&ISR[i]->Destination, save_irq_src_dest[i]);
		openpic_write(&ISR[i]->Vector_Priority, save_irq_src_vp[i]);
		/* make sure mask gets to controller before we return to user */
		do {
			openpic_write(&ISR[i]->Vector_Priority, save_irq_src_vp[i]);
		} while (openpic_readfield(&ISR[i]->Vector_Priority, vppmask)
			 != (save_irq_src_vp[i] & vppmask));
	}
	for (i=0; i<NumProcessors; i++)
		openpic_write(&OpenPIC->Processor[i].Current_Task_Priority,
			      save_cpu_task_pri[i]);

	open_pic.enable = openpic_enable_irq;
	open_pic.disable = openpic_disable_irq;

 	openpic_set_priority(0);

	spin_unlock_irqrestore(&openpic_setup_lock, flags);

	return 0;
}

#endif /* CONFIG_PM */

static struct sysdev_class openpic_sysclass = {
	set_kset_name("openpic"),
};

static struct sys_device device_openpic = {
	.id		= 0,
	.cls		= &openpic_sysclass,
};

static struct sysdev_driver driver_openpic = {
#ifdef CONFIG_PM
	.suspend	= &openpic_suspend,
	.resume		= &openpic_resume,
#endif /* CONFIG_PM */
};

static int __init init_openpic_sysfs(void)
{
	int rc;

	if (!OpenPIC_Addr)
		return -ENODEV;
	printk(KERN_DEBUG "Registering openpic with sysfs...\n");
	rc = sysdev_class_register(&openpic_sysclass);
	if (rc) {
		printk(KERN_ERR "Failed registering openpic sys class\n");
		return -ENODEV;
	}
	rc = sysdev_register(&device_openpic);
	if (rc) {
		printk(KERN_ERR "Failed registering openpic sys device\n");
		return -ENODEV;
	}
	rc = sysdev_driver_register(&openpic_sysclass, &driver_openpic);
	if (rc) {
		printk(KERN_ERR "Failed registering openpic sys driver\n");
		return -ENODEV;
	}
	return 0;
}

subsys_initcall(init_openpic_sysfs);