1 files changed, 105 insertions, 0 deletions
diff --git a/drivers/acpi/gsi.c b/drivers/acpi/gsi.c
new file mode 100644
index 000000000000..38208f2d0e69
--- /dev/null
+++ b/drivers/acpi/gsi.c
@@ -0,0 +1,105 @@
+/*
+ * ACPI GSI IRQ layer
+ *
+ * Copyright (C) 2015 ARM Ltd.
+ * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/acpi.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+
+enum acpi_irq_model_id acpi_irq_model;
+
+static unsigned int acpi_gsi_get_irq_type(int trigger, int polarity)
+{
+	switch (polarity) {
+	case ACPI_ACTIVE_LOW:
+		return trigger == ACPI_EDGE_SENSITIVE ?
+		       IRQ_TYPE_EDGE_FALLING :
+		       IRQ_TYPE_LEVEL_LOW;
+	case ACPI_ACTIVE_HIGH:
+		return trigger == ACPI_EDGE_SENSITIVE ?
+		       IRQ_TYPE_EDGE_RISING :
+		       IRQ_TYPE_LEVEL_HIGH;
+	case ACPI_ACTIVE_BOTH:
+		if (trigger == ACPI_EDGE_SENSITIVE)
+			return IRQ_TYPE_EDGE_BOTH;
+	default:
+		return IRQ_TYPE_NONE;
+	}
+}
+
+/**
+ * acpi_gsi_to_irq() - Retrieve the linux irq number for a given GSI
+ * @gsi: GSI IRQ number to map
+ * @irq: pointer where linux IRQ number is stored
+ *
+ * irq location updated with irq value [>0 on success, 0 on failure]
+ *
+ * Returns: linux IRQ number on success (>0)
+ *          -EINVAL on failure
+ */
+int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
+{
+	/*
+	 * Only default domain is supported at present, always find
+	 * the mapping corresponding to default domain by passing NULL
+	 * as irq_domain parameter
+	 */
+	*irq = irq_find_mapping(NULL, gsi);
+	/*
+	 * *irq == 0 means no mapping, that should
+	 * be reported as a failure
+	 */
+	return (*irq > 0) ? *irq : -EINVAL;
+}
+EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
+
+/**
+ * acpi_register_gsi() - Map a GSI to a linux IRQ number
+ * @dev: device for which IRQ has to be mapped
+ * @gsi: GSI IRQ number
+ * @trigger: trigger type of the GSI number to be mapped
+ * @polarity: polarity of the GSI to be mapped
+ *
+ * Returns: a valid linux IRQ number on success
+ *          -EINVAL on failure
+ */
+int acpi_register_gsi(struct device *dev, u32 gsi, int trigger,
+		      int polarity)
+{
+	unsigned int irq;
+	unsigned int irq_type = acpi_gsi_get_irq_type(trigger, polarity);
+
+	/*
+	 * There is no way at present to look-up the IRQ domain on ACPI,
+	 * hence always create mapping referring to the default domain
+	 * by passing NULL as irq_domain parameter
+	 */
+	irq = irq_create_mapping(NULL, gsi);
+	if (!irq)
+		return -EINVAL;
+
+	/* Set irq type if specified and different than the current one */
+	if (irq_type != IRQ_TYPE_NONE &&
+		irq_type != irq_get_trigger_type(irq))
+		irq_set_irq_type(irq, irq_type);
+	return irq;
+}
+EXPORT_SYMBOL_GPL(acpi_register_gsi);
+
+/**
+ * acpi_unregister_gsi() - Free a GSI<->linux IRQ number mapping
+ * @gsi: GSI IRQ number
+ */
+void acpi_unregister_gsi(u32 gsi)
+{
+	int irq = irq_find_mapping(NULL, gsi);
+
+	irq_dispose_mapping(irq);
+}
+EXPORT_SYMBOL_GPL(acpi_unregister_gsi);