path: root/arch/mips64/sgi-ip27/ip27-irq.c

/* $Id: ip27-irq.c,v 1.8 2000/03/07 15:45:29 ralf Exp $
 *
 * ip27-irq.c: Highlevel interrupt handling for IP27 architecture.
 *
 * Copyright (C) 1999 Ralf Baechle (ralf@gnu.org)
 * Copyright (C) 1999 Silicon Graphics, Inc.
 */
#include <linux/init.h>

#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/timex.h>
#include <linux/malloc.h>
#include <linux/random.h>
#include <linux/smp_lock.h>
#include <linux/kernel_stat.h>
#include <linux/delay.h>

#include <asm/bitops.h>
#include <asm/bootinfo.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/mipsregs.h>
#include <asm/system.h>

#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/pci/bridge.h>
#include <asm/sn/sn0/hub.h>
#include <asm/sn/sn0/ip27.h>
#include <asm/sn/arch.h>

/*
 * Linux has a controller-independent x86 interrupt architecture.
 * every controller has a 'controller-template', that is used
 * by the main code to do the right thing. Each driver-visible
 * interrupt source is transparently wired to the apropriate
 * controller. Thus drivers need not be aware of the
 * interrupt-controller.
 *
 * Various interrupt controllers we handle: 8259 PIC, SMP IO-APIC,
 * PIIX4's internal 8259 PIC and SGI's Visual Workstation Cobalt (IO-)APIC.
 * (IO-APICs assumed to be messaging to Pentium local-APICs)
 *
 * the code is designed to be easily extended with new/different
 * interrupt controllers, without having to do assembly magic.
 */

irq_cpustat_t irq_stat [NR_CPUS];

extern asmlinkage void ip27_irq(void);
int (*irq_cannonicalize)(int irq);

unsigned int local_bh_count[NR_CPUS];
unsigned int local_irq_count[NR_CPUS];
unsigned long spurious_count = 0;

void disable_irq(unsigned int irq_nr)
{
	panic("disable_irq() called ...");
}

void enable_irq(unsigned int irq_nr)
{
	panic("enable_irq() called ...");
}

/* This is stupid for an Origin which can have thousands of IRQs ...  */
static struct irqaction *irq_action[NR_IRQS];

int get_irq_list(char *buf)
{
	int i, len = 0;
	struct irqaction * action;

	for (i = 0 ; i < 32 ; i++) {
		action = irq_action[i];
		if (!action) 
			continue;
		len += sprintf(buf+len, "%2d: %8d %c %s", i, kstat.irqs[0][i],
		               (action->flags & SA_INTERRUPT) ? '+' : ' ',
		               action->name);
		for (action=action->next; action; action = action->next) {
			len += sprintf(buf+len, ",%s %s",
			               (action->flags & SA_INTERRUPT)
			                ? " +" : "",
			                action->name);
		}
		len += sprintf(buf+len, "\n");
	}
	return len;
}

/*
 * do_IRQ handles all normal device IRQ's (the special SMP cross-CPU interrupts
 * have their own specific handlers).
 */
asmlinkage void do_IRQ(int irq, struct pt_regs * regs)
{
	struct irqaction *action;
	int do_random, cpu;

	cpu = smp_processor_id();
	irq_enter(cpu, irq);
	kstat.irqs[cpu][irq]++;

	action = *(irq + irq_action);
	if (action) {
		if (!(action->flags & SA_INTERRUPT))
			__sti();
		action = *(irq + irq_action);
		do_random = 0;
        	do {
			do_random |= action->flags;
			action->handler(irq, action->dev_id, regs);
			action = action->next;
        	} while (action);
		if (do_random & SA_SAMPLE_RANDOM)
			add_interrupt_randomness(irq);
		__cli();
	}
	irq_exit(cpu, irq);

	/* unmasking and bottom half handling is done magically for us. */
}

/*
 * Find first bit set
 */
static int ms1bit(unsigned long x)
{
	int	b;

	if (x >> 32) 	b = 32, x >>= 32;
	else		b  =  0;
	if (x >> 16)	b += 16, x >>= 16;
	if (x >>  8)	b +=  8, x >>=  8;
	if (x >>  4)	b +=  4, x >>=  4;
	if (x >>  2)	b +=  2, x >>=  2;

	return b + (int) (x >> 1);
}
	
/* For now ...  */
void ip27_do_irq(struct pt_regs *regs)
{
	int irq;
	hubreg_t pend0, mask0;

	/* copied from Irix intpend0() */
	while (((pend0 = LOCAL_HUB_L(PI_INT_PEND0)) & 
				(mask0 = LOCAL_HUB_L(PI_INT_MASK0_A))) != 0) {
		do {
			irq = ms1bit(pend0);
			LOCAL_HUB_S(PI_INT_MASK0_A, mask0 & ~(1 << irq));
			LOCAL_HUB_S(PI_INT_PEND_MOD, irq);
			LOCAL_HUB_L(PI_INT_MASK0_A);		/* Flush */
			do_IRQ(irq, regs);
			LOCAL_HUB_S(PI_INT_MASK0_A, mask0);
			pend0 ^= 1ULL << irq;
		} while (pend0);
	}
}


/* Startup one of the (PCI ...) IRQs routes over a bridge.  */
static unsigned int bridge_startup(unsigned int irq)
{
	bridge_t *bridge = (bridge_t *) 0x9200000008000000;
	bridgereg_t br;
	int pin;

	/* FIIIIIXME ...  Temporary kludge.  This knows how interrupts are
	   setup in _my_ Origin.  */
	switch (irq) {
	case IOC3_SERIAL_INT:	pin = 3; break;
	case IOC3_ETH_INT:	pin = 2; break;
	case SCSI1_INT:		pin = 1; break;
	case SCSI0_INT:		pin = 0; break;
	default:		panic("bridge_startup: whoops?");
	}

	br = LOCAL_HUB_L(PI_INT_MASK0_A);
	LOCAL_HUB_S(PI_INT_MASK0_A, br | (1 << irq));
	LOCAL_HUB_L(PI_INT_MASK0_A);			/* Flush */

	bridge->b_int_addr[pin].addr = 0x20000 | irq;
	bridge->b_int_enable |= (1 << pin);
	if (irq < 2) {
		bridgereg_t device;
#if 0
		/*
	 	 * Allocate enough RRBs on the bridge for the DMAs.
	 	 * Right now allocating 2 RRBs on the normal channel
	 	 * and 2 on the virtual channel for slot 0 on the bus.
		 * And same for slot 1, to get ioc3 eth working.
	 	 */
		Not touching b_even_resp	  /* boot doesn't go far */
		bridge->b_even_resp = 0xdd99cc88; /* boot doesn't go far */
		bridge->b_even_resp = 0xcccc8888; /* breaks eth0 */
		bridge->b_even_resp = 0xcc88;	  /* breaks eth0 */
#endif
		/* Turn on bridge swapping */
		device = bridge->b_device[irq].reg;
		device |= BRIDGE_DEV_SWAP_DIR;
		bridge->b_device[irq].reg = device;
	}
	bridge->b_widget.w_tflush;			/* Flush */

	return 0;	/* Never anything pending.  */
}

/* Startup one of the (PCI ...) IRQs routes over a bridge.  */
static unsigned int bridge_shutdown(unsigned int irq)
{
	bridge_t *bridge = (bridge_t *) 0x9200000008000000;
	bridgereg_t br;
	int pin;

	/* FIIIIIXME ...  Temporary kludge.  This knows how interrupts are
	   setup in _my_ Origin.  */
	switch (irq) {
	case IOC3_SERIAL_INT:	pin = 3; break;
	case IOC3_ETH_INT:	pin = 2; break;
	case SCSI1_INT:		pin = 1; break;
	case SCSI0_INT:		pin = 0; break;
	default:		panic("bridge_startup: whoops?");
	}

	br = LOCAL_HUB_L(PI_INT_MASK0_A);
	LOCAL_HUB_S(PI_INT_MASK0_A, br & ~(1 << irq));
	LOCAL_HUB_L(PI_INT_MASK0_A);			/* Flush */

	bridge->b_int_enable &= ~(1 << pin);
	bridge->b_widget.w_tflush;			/* Flush */

	return 0;	/* Never anything pending.  */
}

static void bridge_init(void)
{
	bridge_t *bridge = (bridge_t *) 0x9200000008000000;

	/* Hmm...  IRIX sets additional bits in the address which are
	   documented as reserved in the bridge docs ...  */
	bridge->b_int_mode = 0x0;			/* Don't clear ints */
#if 0
	bridge->b_wid_int_upper = 0x000a8000;           /* Ints to node 0 */
	bridge->b_wid_int_lower = 0x01000090;
	bridge->b_dir_map = 0xa00000;			/* DMA */
#endif /* shouldn't lower= 0x01800090 ??? */
        bridge->b_wid_int_upper = 0x00098000;           /* Ints to node 0 */
        bridge->b_wid_int_lower = 0x01800090;
        bridge->b_dir_map = 0x900000;                   /* DMA */

	bridge->b_int_enable = 0;
	bridge->b_widget.w_tflush;			/* Flush */
	set_cp0_status(SRB_DEV0 | SRB_DEV1, SRB_DEV0 | SRB_DEV1);
}

void irq_debug(void)
{
	bridge_t *bridge = (bridge_t *) 0x9200000008000000;

	printk("bridge->b_int_status = 0x%x\n", bridge->b_int_status);
	printk("bridge->b_int_enable = 0x%x\n", bridge->b_int_enable);
	printk("PI_INT_PEND0   = 0x%x\n", LOCAL_HUB_L(PI_INT_PEND0));
	printk("PI_INT_MASK0_A = 0x%x\n", LOCAL_HUB_L(PI_INT_MASK0_A));
}

int setup_irq(unsigned int irq, struct irqaction *new)
{
	int shared = 0;
	struct irqaction *old, **p;
	unsigned long flags;

	if (new->flags & SA_SAMPLE_RANDOM)
		rand_initialize_irq(irq);

	save_and_cli(flags);
	p = irq_action + irq;
	if ((old = *p) != NULL) {
		/* Can't share interrupts unless both agree to */
		if (!(old->flags & new->flags & SA_SHIRQ)) {
			restore_flags(flags);
			return -EBUSY;
		}

		/* Add new interrupt at end of irq queue */
		do {
			p = &old->next;
			old = *p;
		} while (old);
		shared = 1;
	}

	*p = new;

	if (!shared) {
		bridge_startup(irq);
	}
	restore_flags(flags);

	return 0;
}

int request_irq(unsigned int irq, 
		void (*handler)(int, void *, struct pt_regs *),
		unsigned long irqflags, const char * devname, void *dev_id)
{
	int retval;
	struct irqaction *action;

	if (irq > 9)
		return -EINVAL;
	if (!handler)
		return -EINVAL;

	action = (struct irqaction *)kmalloc(sizeof(*action), GFP_KERNEL);
	if (!action)
		return -ENOMEM;

	action->handler = handler;
	action->flags = irqflags;
	action->mask = 0;
	action->name = devname;
	action->next = NULL;
	action->dev_id = dev_id;

	retval = setup_irq(irq, action);
	if (retval)
		kfree(action);
	return retval;
}

void free_irq(unsigned int irq, void *dev_id)
{
	struct irqaction * action, **p;
	unsigned long flags;

	if (irq > 9) {
		printk("Trying to free IRQ%d\n", irq);
		return;
	}
	for (p = irq + irq_action; (action = *p) != NULL; p = &action->next) {
		if (action->dev_id != dev_id)
			continue;

		/* Found it - now free it */
		save_and_cli(flags);
		*p = action->next;
		if (!irq[irq_action])
			bridge_shutdown(irq);
		restore_flags(flags);
		kfree(action);
		return;
	}
	printk("Trying to free free IRQ%d\n",irq);
}

/* Useless ISA nonsense.  */
unsigned long probe_irq_on (void)
{
	panic("probe_irq_on called!\n");
	return 0;
}

int probe_irq_off (unsigned long irqs)
{
	return 0;
}

static int indy_irq_cannonicalize(int irq)
{
	return irq;	/* Sane hardware, sane code ... */
}

void __init init_IRQ(void)
{
	irq_cannonicalize = indy_irq_cannonicalize;

	bridge_init();
	set_except_vector(0, ip27_irq);
}


#ifdef CONFIG_SMP

/*
 * This following are the global intr on off routines, copied almost
 * entirely from i386 code.
 */

int global_irq_holder = NO_PROC_ID;
spinlock_t global_irq_lock = SPIN_LOCK_UNLOCKED;

extern void show_stack(unsigned long* esp);

static void show(char * str)
{
	int i;
	int cpu = smp_processor_id();

	printk("\n%s, CPU %d:\n", str, cpu);
	printk("irq:  %d [",irqs_running());
	for(i=0;i < smp_num_cpus;i++)
		printk(" %d",local_irq_count(i));
	printk(" ]\nbh:   %d [",spin_is_locked(&global_bh_lock) ? 1 : 0);
	for(i=0;i < smp_num_cpus;i++)
		printk(" %d",local_bh_count(i));

	printk(" ]\nStack dumps:");
	for(i = 0; i < smp_num_cpus; i++) {
		unsigned long esp;
		if (i == cpu)
			continue;
		printk("\nCPU %d:",i);
		printk("Code not developed yet\n");
		/* show_stack(0); */
	}
	printk("\nCPU %d:",cpu);
	printk("Code not developed yet\n");
	/* show_stack(NULL); */
	printk("\n");
}

#define MAXCOUNT 		100000000
#define SYNC_OTHER_CORES(x)	udelay(x+1)

static inline void wait_on_irq(int cpu)
{
	int count = MAXCOUNT;

	for (;;) {

		/*
		 * Wait until all interrupts are gone. Wait
		 * for bottom half handlers unless we're
		 * already executing in one..
		 */
		if (!irqs_running())
			if (local_bh_count(cpu) || !spin_is_locked(&global_bh_lock))
				break;

		/* Duh, we have to loop. Release the lock to avoid deadlocks */
		spin_unlock(&global_irq_lock);

		for (;;) {
			if (!--count) {
				show("wait_on_irq");
				count = ~0;
			}
			__sti();
			SYNC_OTHER_CORES(cpu);
			__cli();
			if (irqs_running())
				continue;
			if (spin_is_locked(&global_irq_lock))
				continue;
			if (!local_bh_count(cpu) && spin_is_locked(&global_bh_lock))
				continue;
			if (spin_trylock(&global_irq_lock))
				break;
		}
	}
}

void synchronize_irq(void)
{
	if (irqs_running()) {
		/* Stupid approach */
		cli();
		sti();
	}
}

static inline void get_irqlock(int cpu)
{
	if (!spin_trylock(&global_irq_lock)) {
		/* do we already hold the lock? */
		if ((unsigned char) cpu == global_irq_holder)
			return;
		/* Uhhuh.. Somebody else got it. Wait.. */
		spin_lock(&global_irq_lock);
	}
	/*
	 * We also to make sure that nobody else is running
	 * in an interrupt context.
	 */
	wait_on_irq(cpu);

	/*
	 * Ok, finally..
	 */
	global_irq_holder = cpu;
}

#define SR_IE	1

void __global_cli(void)
{
	unsigned int flags;

	__save_flags(flags);
	if (flags & SR_IE) {
		int cpu = smp_processor_id();
		__cli();
		if (!local_irq_count(cpu))
			get_irqlock(cpu);
	}
}

void __global_sti(void)
{
	int cpu = smp_processor_id();

	if (!local_irq_count(cpu))
		release_irqlock(cpu);
	__sti();
}

/*
 * SMP flags value to restore to:
 * 0 - global cli
 * 1 - global sti
 * 2 - local cli
 * 3 - local sti
 */
unsigned long __global_save_flags(void)
{
	int retval;
	int local_enabled;
	unsigned long flags;
	int cpu = smp_processor_id();

	__save_flags(flags);
	local_enabled = (flags & SR_IE);
	/* default to local */
	retval = 2 + local_enabled;

	/* check for global flags if we're not in an interrupt */
	if (!local_irq_count(cpu)) {
		if (local_enabled)
			retval = 1;
		if (global_irq_holder == cpu)
			retval = 0;
	}
	return retval;
}

void __global_restore_flags(unsigned long flags)
{
	switch (flags) {
		case 0:
			__global_cli();
			break;
		case 1:
			__global_sti();
			break;
		case 2:
			__cli();
			break;
		case 3:
			__sti();
			break;
		default:
			printk("global_restore_flags: %08lx\n", flags);
	}
}

#endif /* CONFIG_SMP */