Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 184 insertions, 0 deletions

diff --git a/kernel/irq/autoprobe.c b/kernel/irq/autoprobe.c
new file mode 100644
index 000000000..ae60cae24
--- /dev/null
+++ b/kernel/irq/autoprobe.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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_activate_and_startup(desc, IRQ_NORESEND))
+				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_and_deactivate(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_and_deactivate(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_and_deactivate(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);
+