Release 4.15 kernel/irq/autoprobe.c
// SPDX-License-Identifier: GPL-2.0
/*
* 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_activate_and_startup(desc, IRQ_NORESEND);
}
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, IRQ_NORESEND, IRQ_START_FORCE))
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;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Ingo Molnar | 151 | 58.53% | 4 | 18.18% |
| Thomas Gleixner | 93 | 36.05% | 15 | 68.18% |
| Yinghai Lu | 6 | 2.33% | 1 | 4.55% |
| Luca Falavigna | 4 | 1.55% | 1 | 4.55% |
| Arjan van de Ven | 4 | 1.55% | 1 | 4.55% |
| Total | 258 | 100.00% | 22 | 100.00% |
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;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Ingo Molnar | 77 | 75.49% | 3 | 37.50% |
| Thomas Gleixner | 25 | 24.51% | 5 | 62.50% |
| Total | 102 | 100.00% | 8 | 100.00% |
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;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Ingo Molnar | 90 | 77.59% | 3 | 33.33% |
| Thomas Gleixner | 26 | 22.41% | 6 | 66.67% |
| Total | 116 | 100.00% | 9 | 100.00% |
EXPORT_SYMBOL(probe_irq_off);
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Ingo Molnar | 350 | 67.18% | 5 | 19.23% |
| Thomas Gleixner | 145 | 27.83% | 16 | 61.54% |
| Luca Falavigna | 7 | 1.34% | 1 | 3.85% |
| Arjan van de Ven | 7 | 1.34% | 1 | 3.85% |
| Yinghai Lu | 6 | 1.15% | 1 | 3.85% |
| James Bottomley | 5 | 0.96% | 1 | 3.85% |
| Greg Kroah-Hartman | 1 | 0.19% | 1 | 3.85% |
| Total | 521 | 100.00% | 26 | 100.00% |
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