irq.c

该文件是rt_linux

 *	and a mask of potential interrupt lines is returned.
 *
 */

unsigned long probe_irq_on(void)
{
	unsigned int i;
	irq_desc_t *desc;
	unsigned long val;
	unsigned long delay;

	down(&probe_sem);
	/*
	 * something may have generated an irq long ago and we want to
	 * flush such a longstanding irq before considering it as spurious.
	 */
	for (i = NR_IRQS-1; i > 0; i--)  {
		desc = irq_desc(i);

		spin_lock_irq(&desc->lock);
		if (!desc->action)
			desc->handler->startup(i);
		spin_unlock_irq(&desc->lock);
	}

	/* Wait for longstanding interrupts to trigger. */
	for (delay = jiffies + HZ/50; time_after(delay, jiffies); )
		/* about 20ms delay */ synchronize_irq();

	/*
	 * enable any unassigned irqs
	 * (we must startup again here because if a longstanding irq
	 * happened in the previous stage, it may have masked itself)
	 */
	for (i = NR_IRQS-1; i > 0; i--) {
		desc = irq_desc(i);

		spin_lock_irq(&desc->lock);
		if (!desc->action) {
			desc->status |= IRQ_AUTODETECT | IRQ_WAITING;
			if (desc->handler->startup(i))
				desc->status |= IRQ_PENDING;
		}
		spin_unlock_irq(&desc->lock);
	}

	/*
	 * Wait for spurious interrupts to trigger
	 */
	for (delay = jiffies + HZ/10; time_after(delay, jiffies); )
		/* about 100ms delay */ synchronize_irq();

	/*
	 * Now filter out any obviously spurious interrupts
	 */
	val = 0;
	for (i = 0; i < NR_IRQS; i++) {
		irq_desc_t *desc = irq_desc(i);
		unsigned int status;

		spin_lock_irq(&desc->lock);
		status = desc->status;

		if (status & IRQ_AUTODETECT) {
			/* It triggered already - consider it spurious. */
			if (!(status & IRQ_WAITING)) {
				desc->status = status & ~IRQ_AUTODETECT;
				desc->handler->shutdown(i);
			} else
				if (i < 32)
					val |= 1 << i;
		}
		spin_unlock_irq(&desc->lock);
	}

	return val;
}

/**
 *	probe_irq_mask - scan a bitmap of interrupt lines
 *	@val:	mask of interrupts to consider
 *
 *	Scan the ISA bus interrupt lines and return a bitmap of
 *	active interrupts. The interrupt probe logic state is then
 *	returned to its previous value.
 *
 *	Note: we need to scan all the irq's even though we will
 *	only return ISA irq numbers - just so that we reset them
 *	all to a known state.
 */

unsigned int probe_irq_mask(unsigned long val)
{
	int i;
	unsigned int mask;

	mask = 0;
	for (i = 0; i < 16; i++) {
		irq_desc_t *desc = irq_desc(i);
		unsigned int status;

		spin_lock_irq(&desc->lock);
		status = desc->status;

		if (status & IRQ_AUTODETECT) {
			if (!(status & IRQ_WAITING))
				mask |= 1 << i;

			desc->status = status & ~IRQ_AUTODETECT;
			desc->handler->shutdown(i);
		}
		spin_unlock_irq(&desc->lock);
	}
	up(&probe_sem);

	return mask & val;
}

/**
 *	probe_irq_off	- end an interrupt autodetect
 *	@val: mask of potential interrupts (unused)
 *
 *	Scans the unused interrupt lines and returns the line which
 *	appears to have triggered the interrupt. If no interrupt was
 *	found then zero is returned. If more than one interrupt is
 *	found then minus the first candidate is returned to indicate
 *	their is doubt.
 *
 *	The interrupt probe logic state is returned to its previous
 *	value.
 *
 *	BUGS: When used in a module (which arguably shouldnt happen)
 *	nothing prevents two IRQ probe callers from overlapping. The
 *	results of this are non-optimal.
 */

int probe_irq_off(unsigned long val)
{
	int i, irq_found, nr_irqs;

	nr_irqs = 0;
	irq_found = 0;
	for (i = 0; i < NR_IRQS; i++) {
		irq_desc_t *desc = irq_desc(i);
		unsigned int status;

		spin_lock_irq(&desc->lock);
		status = desc->status;

		if (status & IRQ_AUTODETECT) {
			if (!(status & IRQ_WAITING)) {
				if (!nr_irqs)
					irq_found = i;
				nr_irqs++;
			}
			desc->status = status & ~IRQ_AUTODETECT;
			desc->handler->shutdown(i);
		}
		spin_unlock_irq(&desc->lock);
	}
	up(&probe_sem);

	if (nr_irqs > 1)
		irq_found = -irq_found;
	return irq_found;
}

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

	/*
	 * Some drivers like serial.c use request_irq() heavily,
	 * so we have to be careful not to interfere with a
	 * running system.
	 */
	if (new->flags & SA_SAMPLE_RANDOM) {
		/*
		 * This function might sleep, we want to call it first,
		 * outside of the atomic block.
		 * Yes, this might clear the entropy pool if the wrong
		 * driver is attempted to be loaded, without actually
		 * installing a new handler, but is this really a problem,
		 * only the sysadmin is able to do this.
		 */
		rand_initialize_irq(irq);
	}

	if (new->flags & SA_PERCPU_IRQ) {
		desc->status |= IRQ_PER_CPU;
		desc->handler = &irq_type_ia64_lsapic;
	}

	/*
	 * The following block of code has to be executed atomically
	 */
	spin_lock_irqsave(&desc->lock,flags);
	p = &desc->action;
	if ((old = *p) != NULL) {
		/* Can't share interrupts unless both agree to */
		if (!(old->flags & new->flags & SA_SHIRQ)) {
			spin_unlock_irqrestore(&desc->lock,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) {
		desc->depth = 0;
		desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | IRQ_WAITING);
		desc->handler->startup(irq);
	}
	spin_unlock_irqrestore(&desc->lock,flags);

	register_irq_proc(irq);
	return 0;
}

static struct proc_dir_entry * root_irq_dir;
static struct proc_dir_entry * irq_dir [NR_IRQS];

#define HEX_DIGITS 8

static unsigned int parse_hex_value (const char *buffer,
		unsigned long count, unsigned long *ret)
{
	unsigned char hexnum [HEX_DIGITS];
	unsigned long value;
	int i;

	if (!count)
		return -EINVAL;
	if (count > HEX_DIGITS)
		count = HEX_DIGITS;
	if (copy_from_user(hexnum, buffer, count))
		return -EFAULT;

	/*
	 * Parse the first 8 characters as a hex string, any non-hex char
	 * is end-of-string. '00e1', 'e1', '00E1', 'E1' are all the same.
	 */
	value = 0;

	for (i = 0; i < count; i++) {
		unsigned int c = hexnum[i];

		switch (c) {
			case '0' ... '9': c -= '0'; break;
			case 'a' ... 'f': c -= 'a'-10; break;
			case 'A' ... 'F': c -= 'A'-10; break;
		default:
			goto out;
		}
		value = (value << 4) | c;
	}
out:
	*ret = value;
	return 0;
}

#if CONFIG_SMP

static struct proc_dir_entry * smp_affinity_entry [NR_IRQS];

static unsigned long irq_affinity [NR_IRQS] = { [0 ... NR_IRQS-1] = ~0UL };
static char irq_redir [NR_IRQS]; // = { [0 ... NR_IRQS-1] = 1 };

void set_irq_affinity_info(int irq, int hwid, int redir)
{
	unsigned long mask = 1UL<<cpu_logical_id(hwid);

	if (irq >= 0 && irq < NR_IRQS) {
		irq_affinity[irq] = mask;
		irq_redir[irq] = (char) (redir & 0xff);
	}
}

static int irq_affinity_read_proc (char *page, char **start, off_t off,
			int count, int *eof, void *data)
{
	if (count < HEX_DIGITS+3)
		return -EINVAL;
	return sprintf (page, "%s%08lx\n", irq_redir[(long)data] ? "r " : "",
			irq_affinity[(long)data]);
}

static int irq_affinity_write_proc (struct file *file, const char *buffer,
					unsigned long count, void *data)
{
	int irq = (long) data, full_count = count, err;
	unsigned long new_value;
	const char *buf = buffer;
	int redir;

	if (!irq_desc(irq)->handler->set_affinity)
		return -EIO;

	if (buf[0] == 'r' || buf[0] == 'R') {
		++buf;
		while (*buf == ' ') ++buf;
		redir = 1;
	} else
		redir = 0;

	err = parse_hex_value(buf, count, &new_value);

	/*
	 * Do not allow disabling IRQs completely - it's a too easy
	 * way to make the system unusable accidentally :-) At least
	 * one online CPU still has to be targeted.
	 */
	if (!(new_value & cpu_online_map))
		return -EINVAL;

	irq_desc(irq)->handler->set_affinity(irq | (redir? IA64_IRQ_REDIRECTED :0), new_value);

	return full_count;
}

#endif /* CONFIG_SMP */

static int prof_cpu_mask_read_proc (char *page, char **start, off_t off,
			int count, int *eof, void *data)
{
	unsigned long *mask = (unsigned long *) data;
	if (count < HEX_DIGITS+1)
		return -EINVAL;
	return sprintf (page, "%08lx\n", *mask);
}

static int prof_cpu_mask_write_proc (struct file *file, const char *buffer,
					unsigned long count, void *data)
{
	unsigned long *mask = (unsigned long *) data, full_count = count, err;
	unsigned long new_value;

	err = parse_hex_value(buffer, count, &new_value);
	if (err)
		return err;

	*mask = new_value;
	return full_count;
}

#define MAX_NAMELEN 10

static void register_irq_proc (unsigned int irq)
{
	char name [MAX_NAMELEN];

	if (!root_irq_dir || (irq_desc(irq)->handler == &no_irq_type) || irq_dir[irq])
		return;

	memset(name, 0, MAX_NAMELEN);
	sprintf(name, "%d", irq);

	/* create /proc/irq/1234 */
	irq_dir[irq] = proc_mkdir(name, root_irq_dir);

#if CONFIG_SMP
	{
		struct proc_dir_entry *entry;
		/* create /proc/irq/1234/smp_affinity */
		entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);

		if (entry) {
			entry->nlink = 1;
			entry->data = (void *)(long)irq;
			entry->read_proc = irq_affinity_read_proc;
			entry->write_proc = irq_affinity_write_proc;
		}

		smp_affinity_entry[irq] = entry;
	}
#endif
}

unsigned long prof_cpu_mask = -1;

void init_irq_proc (void)
{
	struct proc_dir_entry *entry;
	int i;

	/* create /proc/irq */
	root_irq_dir = proc_mkdir("irq", 0);

	/* create /proc/irq/prof_cpu_mask */
	entry = create_proc_entry("prof_cpu_mask", 0600, root_irq_dir);

	if (!entry)
		return;

	entry->nlink = 1;
	entry->data = (void *)&prof_cpu_mask;
	entry->read_proc = prof_cpu_mask_read_proc;
	entry->write_proc = prof_cpu_mask_write_proc;

	/*
	 * Create entries for all existing IRQs.
	 */
	for (i = 0; i < NR_IRQS; i++) {
		if (irq_desc(i)->handler == &no_irq_type)
			continue;
		register_irq_proc(i);
	}
}