From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 kernel/irq/resend.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 kernel/irq/resend.c

(limited to 'kernel/irq/resend.c')

diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
new file mode 100644
index 000000000..9065107f0
--- /dev/null
+++ b/kernel/irq/resend.c
@@ -0,0 +1,91 @@
+/*
+ * linux/kernel/irq/resend.c
+ *
+ * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
+ * Copyright (C) 2005-2006, Thomas Gleixner
+ *
+ * This file contains the IRQ-resend code
+ *
+ * If the interrupt is waiting to be processed, we try to re-run it.
+ * We can't directly run it from here since the caller might be in an
+ * interrupt-protected region. Not all irq controller chips can
+ * retrigger interrupts at the hardware level, so in those cases
+ * we allow the resending of IRQs via a tasklet.
+ */
+
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/interrupt.h>
+
+#include "internals.h"
+
+#ifdef CONFIG_HARDIRQS_SW_RESEND
+
+/* Bitmap to handle software resend of interrupts: */
+static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS);
+
+/*
+ * Run software resends of IRQ's
+ */
+static void resend_irqs(unsigned long arg)
+{
+	struct irq_desc *desc;
+	int irq;
+
+	while (!bitmap_empty(irqs_resend, nr_irqs)) {
+		irq = find_first_bit(irqs_resend, nr_irqs);
+		clear_bit(irq, irqs_resend);
+		desc = irq_to_desc(irq);
+		local_irq_disable();
+		desc->handle_irq(irq, desc);
+		local_irq_enable();
+	}
+}
+
+/* Tasklet to handle resend: */
+static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
+
+#endif
+
+/*
+ * IRQ resend
+ *
+ * Is called with interrupts disabled and desc->lock held.
+ */
+void check_irq_resend(struct irq_desc *desc, unsigned int irq)
+{
+	/*
+	 * We do not resend level type interrupts. Level type
+	 * interrupts are resent by hardware when they are still
+	 * active. Clear the pending bit so suspend/resume does not
+	 * get confused.
+	 */
+	if (irq_settings_is_level(desc)) {
+		desc->istate &= ~IRQS_PENDING;
+		return;
+	}
+	if (desc->istate & IRQS_REPLAY)
+		return;
+	if (desc->istate & IRQS_PENDING) {
+		desc->istate &= ~IRQS_PENDING;
+		desc->istate |= IRQS_REPLAY;
+
+		if (!desc->irq_data.chip->irq_retrigger ||
+		    !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) {
+#ifdef CONFIG_HARDIRQS_SW_RESEND
+			/*
+			 * If the interrupt has a parent irq and runs
+			 * in the thread context of the parent irq,
+			 * retrigger the parent.
+			 */
+			if (desc->parent_irq &&
+			    irq_settings_is_nested_thread(desc))
+				irq = desc->parent_irq;
+			/* Set it pending and activate the softirq: */
+			set_bit(irq, irqs_resend);
+			tasklet_schedule(&resend_tasklet);
+#endif
+		}
+	}
+}
-- 
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