irq.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

		return;
	}

	if(action->flags & SA_STATIC_ALLOC) {
		printk("Attempt to free statically allocated IRQ %d (%s)\n",
		       bucket->pil, action->name);
		return;
	}

	save_and_cli(flags);
	if(action && tmp)
		tmp->next = action->next;
	else
		*(bucket->pil + irq_action) = action->next;

	if (bucket != &pil0_dummy_bucket) {
		unsigned long imap = bucket->imap;
		void **vector, *orig;
		int ent;

		orig = bucket->irq_info;
		vector = (void **)orig;

		if ((bucket->flags & IBF_MULTI) != 0) {
			int other = 0;
			void *orphan = NULL;
			for(ent = 0; ent < 4; ent++) {
				if(vector[ent] == action)
					vector[ent] = NULL;
				else if(vector[ent] != NULL) {
					orphan = vector[ent];
					other++;
				}
			}

			/* Only free when no other shared irq
			 * uses this bucket.
			 */
			if(other) {
				if (other == 1) {
					/* Convert back to non-shared bucket. */
					bucket->irq_info = orphan;
					bucket->flags &= ~(IBF_MULTI);
					kfree(vector);
				}
				goto out;
			}
		} else {
			bucket->irq_info = NULL;
		}

		/* This unique interrupt source is now inactive. */
		bucket->flags &= ~IBF_ACTIVE;

		/* See if any other buckets share this bucket's IMAP
		 * and are still active.
		 */
		for(ent = 0; ent < NUM_IVECS; ent++) {
			bp = &ivector_table[ent];
			if(bp != bucket		&&
			   bp->imap == imap	&&
			   (bp->flags & IBF_ACTIVE) != 0)
				break;
		}

		/* Only disable when no other sub-irq levels of
		 * the same IMAP are active.
		 */
		if (ent == NUM_IVECS)
			disable_irq(irq);
	}

out:
	kfree(action);
	restore_flags(flags);
}

#ifdef CONFIG_SMP

/* Who has the global irq brlock */
unsigned char global_irq_holder = NO_PROC_ID;

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

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

#define MAXCOUNT 100000000

#if 0
#define SYNC_OTHER_ULTRAS(x)	udelay(x+1)
#else
#define SYNC_OTHER_ULTRAS(x)	membar("#Sync");
#endif

void synchronize_irq(void)
{
	if (irqs_running()) {
		cli();
		sti();
	}
}

static inline void get_irqlock(int cpu)
{
	int count;

	if ((unsigned char)cpu == global_irq_holder)
		return;

	count = MAXCOUNT;
again:
	br_write_lock(BR_GLOBALIRQ_LOCK);
	for (;;) {
		spinlock_t *lock;

		if (!irqs_running() &&
		    (local_bh_count(smp_processor_id()) || !spin_is_locked(&global_bh_lock)))
			break;

		br_write_unlock(BR_GLOBALIRQ_LOCK);
		lock = &__br_write_locks[BR_GLOBALIRQ_LOCK].lock;
		while (irqs_running() ||
		       spin_is_locked(lock) ||
		       (!local_bh_count(smp_processor_id()) && spin_is_locked(&global_bh_lock))) {
			if (!--count) {
				show("get_irqlock");
				count = (~0 >> 1);
			}
			__sti();
			SYNC_OTHER_ULTRAS(cpu);
			__cli();
		}
		goto again;
	}

	global_irq_holder = cpu;
}

void __global_cli(void)
{
	unsigned long flags;

	__save_flags(flags);
	if(flags == 0) {
		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();
}

unsigned long __global_save_flags(void)
{
	unsigned long flags, local_enabled, retval;

	__save_flags(flags);
	local_enabled = ((flags == 0) ? 1 : 0);
	retval = 2 + local_enabled;
	if (! local_irq_count(smp_processor_id())) {
		if (local_enabled)
			retval = 1;
		if (global_irq_holder == (unsigned char) smp_processor_id())
			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:
	{
		unsigned long pc;
		__asm__ __volatile__("mov %%i7, %0" : "=r" (pc));
		printk("global_restore_flags: Bogon flags(%016lx) caller %016lx\n",
		       flags, pc);
	}
	}
}

#endif /* CONFIG_SMP */

void catch_disabled_ivec(struct pt_regs *regs)
{
	int cpu = smp_processor_id();
	struct ino_bucket *bucket = __bucket(*irq_work(cpu, 0));

	/* We can actually see this on Ultra/PCI PCI cards, which are bridges
	 * to other devices.  Here a single IMAP enabled potentially multiple
	 * unique interrupt sources (which each do have a unique ICLR register.
	 *
	 * So what we do is just register that the IVEC arrived, when registered
	 * for real the request_irq() code will check the bit and signal
	 * a local CPU interrupt for it.
	 */
#if 0
	printk("IVEC: Spurious interrupt vector (%x) received at (%016lx)\n",
	       bucket - &ivector_table[0], regs->tpc);
#endif
	*irq_work(cpu, 0) = 0;
	bucket->pending = 1;
}

/* Tune this... */
#define FORWARD_VOLUME		12

#ifdef CONFIG_SMP

static inline void redirect_intr(int cpu, struct ino_bucket *bp)
{
	/* Ok, here is what is going on:
	 * 1) Retargeting IRQs on Starfire is very
	 *    expensive so just forget about it on them.
	 * 2) Moving around very high priority interrupts
	 *    is a losing game.
	 * 3) If the current cpu is idle, interrupts are
	 *    useful work, so keep them here.  But do not
	 *    pass to our neighbour if he is not very idle.
	 * 4) If sysadmin explicitly asks for directed intrs,
	 *    Just Do It.
	 */
	struct irqaction *ap = bp->irq_info;
	unsigned long cpu_mask = get_smpaff_in_irqaction(ap);
	unsigned int buddy, ticks;

	if (cpu_mask == 0)
		cpu_mask = ~0UL;

	if (this_is_starfire != 0 ||
	    bp->pil >= 10 || current->pid == 0)
		goto out;

	/* 'cpu' is the MID (ie. UPAID), calculate the MID
	 * of our buddy.
	 */
	buddy = cpu_number_map(cpu) + 1;
	if (buddy >= NR_CPUS ||
	    cpu_logical_map(buddy) == -1)
		buddy = 0;

	ticks = 0;
	while ((cpu_mask & (1UL << buddy)) == 0) {
		buddy++;
		if (buddy >= NR_CPUS ||
		    cpu_logical_map(buddy) == -1)
			buddy = cpu_logical_map(0);
		if (++ticks > NR_CPUS) {
			put_smpaff_in_irqaction(ap, 0);
			goto out;
		}
	}

	if (buddy == cpu_number_map(cpu))
		goto out;

	buddy = cpu_logical_map(buddy);

	/* Voo-doo programming. */
	if (cpu_data[buddy].idle_volume < FORWARD_VOLUME)
		goto out;

	/* This just so happens to be correct on Cheetah
	 * at the moment.
	 */
	buddy <<= 26;

	/* Push it to our buddy. */
	upa_writel(buddy | IMAP_VALID, bp->imap);

out:
	return;
}

#endif

void handler_irq(int irq, struct pt_regs *regs)
{
	struct ino_bucket *bp, *nbp;
	int cpu = smp_processor_id();

#ifndef CONFIG_SMP
	/*
	 * Check for TICK_INT on level 14 softint.
	 */
	{
		unsigned long clr_mask = 1 << irq;
		unsigned long tick_mask;

		if (SPARC64_USE_STICK)
			tick_mask = (1UL << 16);
		else
			tick_mask = (1UL << 0);
		if ((irq == 14) && (get_softint() & tick_mask)) {
			irq = 0;
			clr_mask = tick_mask;
		}
		clear_softint(clr_mask);
	}
#else
	int should_forward = 1;

	clear_softint(1 << irq);
#endif

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

#ifdef CONFIG_PCI
	if (irq == 9)
		kbd_pt_regs = regs;
#endif

	/* Sliiiick... */
#ifndef CONFIG_SMP
	bp = ((irq != 0) ?
	      __bucket(xchg32(irq_work(cpu, irq), 0)) :
	      &pil0_dummy_bucket);
#else
	bp = __bucket(xchg32(irq_work(cpu, irq), 0));
#endif
	for ( ; bp != NULL; bp = nbp) {
		unsigned char flags = bp->flags;
		unsigned char random = 0;

		nbp = __bucket(bp->irq_chain);
		bp->irq_chain = 0;

		if ((flags & IBF_ACTIVE) != 0) {
#ifdef CONFIG_PCI
			if ((flags & IBF_DMA_SYNC) != 0) {
				upa_readl(dma_sync_reg_table[bp->synctab_ent]);
				upa_readq(pci_dma_wsync);
			}
#endif
			if ((flags & IBF_MULTI) == 0) {
				struct irqaction *ap = bp->irq_info;
				ap->handler(__irq(bp), ap->dev_id, regs);
				random |= ap->flags & SA_SAMPLE_RANDOM;
			} else {
				void **vector = (void **)bp->irq_info;
				int ent;
				for (ent = 0; ent < 4; ent++) {
					struct irqaction *ap = vector[ent];
					if (ap != NULL) {
						ap->handler(__irq(bp), ap->dev_id, regs);
						random |= ap->flags & SA_SAMPLE_RANDOM;
					}
				}
			}
			/* Only the dummy bucket lacks IMAP/ICLR. */
			if (bp->pil != 0) {
#ifdef CONFIG_SMP
				if (should_forward) {
					redirect_intr(cpu, bp);
					should_forward = 0;
				}
#endif
				upa_writel(ICLR_IDLE, bp->iclr);
				/* Test and add entropy */
				if (random)
					add_interrupt_randomness(irq);
			}
		} else
			bp->pending = 1;
	}
	irq_exit(cpu, irq);
}

#ifdef CONFIG_BLK_DEV_FD
extern void floppy_interrupt(int irq, void *dev_cookie, struct pt_regs *regs);

void sparc_floppy_irq(int irq, void *dev_cookie, struct pt_regs *regs)
{
	struct irqaction *action = *(irq + irq_action);
	struct ino_bucket *bucket;
	int cpu = smp_processor_id();

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

	*(irq_work(cpu, irq)) = 0;
	bucket = get_ino_in_irqaction(action) + ivector_table;

	floppy_interrupt(irq, dev_cookie, regs);
	upa_writel(ICLR_IDLE, bucket->iclr);

	irq_exit(cpu, irq);
}
#endif

/* The following assumes that the branch lies before the place we
 * are branching to.  This is the case for a trap vector...
 * You have been warned.
 */
#define SPARC_BRANCH(dest_addr, inst_addr) \
          (0x10800000 | ((((dest_addr)-(inst_addr))>>2)&0x3fffff))

#define SPARC_NOP (0x01000000)

static void install_fast_irq(unsigned int cpu_irq,
			     void (*handler)(int, void *, struct pt_regs *))
{
	extern unsigned long sparc64_ttable_tl0;
	unsigned long ttent = (unsigned long) &sparc64_ttable_tl0;
	unsigned int *insns;

	ttent += 0x820;
	ttent += (cpu_irq - 1) << 5;
	insns = (unsigned int *) ttent;
	insns[0] = SPARC_BRANCH(((unsigned long) handler),
				((unsigned long)&insns[0]));
	insns[1] = SPARC_NOP;
	__asm__ __volatile__("membar #StoreStore; flush %0" : : "r" (ttent));
}

int request_fast_irq(unsigned int irq,
		     void (*handler)(int, void *, struct pt_regs *),
		     unsigned long irqflags, const char *name, void *dev_id)
{
	struct irqaction *action;
	struct ino_bucket *bucket = __bucket(irq);
	unsigned long flags;

	/* No pil0 dummy buckets allowed here. */
	if (bucket < &ivector_table[0] ||
	    bucket >= &ivector_table[NUM_IVECS]) {
		unsigned int *caller;

		__asm__ __volatile__("mov %%i7, %0" : "=r" (caller));
		printk(KERN_CRIT "request_fast_irq: Old style IRQ registry attempt "
		       "from %p, irq %08x.\n", caller, irq);
		return -EINVAL;
	}	
	
	if(!handler)
		return -EINVAL;

	if ((bucket->pil == 0) || (bucket->pil == 14)) {
		printk("request_fast_irq: Trying to register shared IRQ 0 or 14.\n");
		return -EBUSY;
	}

	action = *(bucket->pil + irq_action);
	if(action) {
		if(action->flags & SA_SHIRQ)
			panic("Trying to register fast irq when already shared.\n");
		if(irqflags & SA_SHIRQ)
			panic("Trying to register fast irq as shared.\n");
		printk("request_fast_irq: Trying to register yet already owned.\n");
		return -EBUSY;
	}

	/*