/*
 * linux/kernel/irq/autoprobe.c
 *
 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
 *
 * This file contains the interrupt probing code and driver APIs.
 */

#include <linux/irq.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/async.h>

#include "internals.h"

/*
 * Autodetection depends on the fact that any interrupt that
 * comes in on to an unassigned handler will get stuck with
 * "IRQS_WAITING" cleared and the interrupt disabled.
 */
static DEFINE_MUTEX(probing_active);

/**
 *	probe_irq_on	- begin an interrupt autodetect
 *
 *	Commence probing for an interrupt. The interrupts are scanned
 *	and a mask of potential interrupt lines is returned.
 *
 */
unsigned long probe_irq_on(void)
{
	struct irq_desc *desc;
	unsigned long mask = 0;
	int i;

	/*
	 * quiesce the kernel, or at least the asynchronous portion
	 */
	async_synchronize_full();
	mutex_lock(&probing_active);
	/*
	 * something may have generated an irq long ago and we want to
	 * flush such a longstanding irq before considering it as spurious.
	 */
	for_each_irq_desc_reverse(i, desc) {
		raw_spin_lock_irq(&desc->lock);
		if (!desc->action && irq_settings_can_probe(desc)) {
			/*
			 * Some chips need to know about probing in
			 * progress:
			 */
			if (desc->irq_data.chip->irq_set_type)
				desc->irq_data.chip->irq_set_type(&desc->irq_data,
							 IRQ_TYPE_PROBE);
			irq_startup(desc, false);
		}
		raw_spin_unlock_irq(&desc->lock);
	}

	/* Wait for longstanding interrupts to trigger. */
	msleep(20);

	/*
	 * 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_each_irq_desc_reverse(i, desc) {
		raw_spin_lock_irq(&desc->lock);
		if (!desc->action && irq_settings_can_probe(desc)) {
			desc->istate |= IRQS_AUTODETECT | IRQS_WAITING;
			if (irq_startup(desc, false))
				desc->istate |= IRQS_PENDING;
		}
		raw_spin_unlock_irq(&desc->lock);
	}

	/*
	 * Wait for spurious interrupts to trigger
	 */
	msleep(100);

	/*
	 * Now filter out any obviously spurious interrupts
	 */
	for_each_irq_desc(i, desc) {
		raw_spin_lock_irq(&desc->lock);

		if (desc->istate & IRQS_AUTODETECT) {
			/* It triggered already - consider it spurious. */
			if (!(desc->istate & IRQS_WAITING)) {
				desc->istate &= ~IRQS_AUTODETECT;
				irq_shutdown(desc);
			} else
				if (i < 32)
					mask |= 1 << i;
		}
		raw_spin_unlock_irq(&desc->lock);
	}

	return mask;
}
EXPORT_SYMBOL(probe_irq_on);

/**
 *	probe_irq_mask - scan a bitmap of interrupt lines
 *	@val:	mask of interrupts to consider
 *
 *	Scan the interrupt lines and return a bitmap of active
 *	autodetect 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 autodetect irq numbers - just so that we reset
 *	them all to a known state.
 */
unsigned int probe_irq_mask(unsigned long val)
{
	unsigned int mask = 0;
	struct irq_desc *desc;
	int i;

	for_each_irq_desc(i, desc) {
		raw_spin_lock_irq(&desc->lock);
		if (desc->istate & IRQS_AUTODETECT) {
			if (i < 16 && !(desc->istate & IRQS_WAITING))
				mask |= 1 << i;

			desc->istate &= ~IRQS_AUTODETECT;
			irq_shutdown(desc);
		}
		raw_spin_unlock_irq(&desc->lock);
	}
	mutex_unlock(&probing_active);

	return mask & val;
}
EXPORT_SYMBOL(probe_irq_mask);

/**
 *	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 shouldn't 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 = 0, nr_of_irqs = 0;
	struct irq_desc *desc;

	for_each_irq_desc(i, desc) {
		raw_spin_lock_irq(&desc->lock);

		if (desc->istate & IRQS_AUTODETECT) {
			if (!(desc->istate & IRQS_WAITING)) {
				if (!nr_of_irqs)
					irq_found = i;
				nr_of_irqs++;
			}
			desc->istate &= ~IRQS_AUTODETECT;
			irq_shutdown(desc);
		}
		raw_spin_unlock_irq(&desc->lock);
	}
	mutex_unlock(&probing_active);

	if (nr_of_irqs > 1)
		irq_found = -irq_found;

	return irq_found;
}
EXPORT_SYMBOL(probe_irq_off);

&gt;</td><td class='right'>2017-01-27 12:36:39 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-27 12:36:39 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/bluetooth/leds.h?id=2fb78e89405f4321b86274a0c24b30896dd50529'>2fb78e89405f4321b86274a0c24b30896dd50529</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/bluetooth/leds.h?id=2fb78e89405f4321b86274a0c24b30896dd50529'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=2fb78e89405f4321b86274a0c24b30896dd50529'>4de241e242441b80bd3f0022fc546bb07374571f</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/bluetooth/leds.h?id=2fb78e89405f4321b86274a0c24b30896dd50529'>net/bluetooth/leds.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/bluetooth/leds.h?id=dd3b9f25c867cb2507a45e436d6ede8eb08e7b05'>dd3b9f25c867cb2507a45e436d6ede8eb08e7b05</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/bluetooth/leds.h?id=2fb78e89405f4321b86274a0c24b30896dd50529&amp;id2=dd3b9f25c867cb2507a45e436d6ede8eb08e7b05'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/bluetooth/leds.h?id=c14024dbb156c8392908aaa822097d27c6af8ec8'>c14024dbb156c8392908aaa822097d27c6af8ec8</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/bluetooth/leds.h?id=2fb78e89405f4321b86274a0c24b30896dd50529&amp;id2=c14024dbb156c8392908aaa822097d27c6af8ec8'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge branch 'for-linus' of git://git.kernel.dk/linux-block</div><div class='commit-msg'>Pull block fixes from Jens Axboe:
 "A set of fixes for this series. This contains:

   - Set of fixes for the nvme target code

   - A revert of patch from this merge window, causing a regression with
     WRITE_SAME on iSCSI targets at least.

   - A fix for a use-after-free in the new O_DIRECT bdev code.

   - Two fixes for the xen-blkfront driver"

* 'for-linus' of git://git.kernel.dk/linux-block:
  Revert "sd: remove __data_len hack for WRITE SAME"
  nvme-fc: use blk_rq_nr_phys_segments
  nvmet-rdma: Fix missing dma sync to nvme data structures
  nvmet: Call fatal_error from keep-alive timout expiration
  nvmet: cancel fatal error and flush async work before free controller
  nvmet: delete controllers deletion upon subsystem release
  nvmet_fc: correct logic in disconnect queue LS handling
  block: fix use after free in __blkdev_direct_IO
  xen-blkfront: correct maximum segment accounting
  xen-blkfront: feature flags handling adjustments
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=2fb78e89405f4321b86274a0c24b30896dd50529'>Diffstat</a> (limited to 'net/bluetooth/leds.h')</div><table summary='diffstat' class='diffstat'>