1 files changed, 43 insertions, 0 deletions
diff --git a/src/soc/intel/apollolake/itss.c b/src/soc/intel/apollolake/itss.c
new file mode 100644
index 0000000000..60d3e06406
--- /dev/null
+++ b/src/soc/intel/apollolake/itss.c
@@ -0,0 +1,43 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2016 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
+ * GNU General Public License for more details.
+ */
+
+#include <stdint.h>
+#include <soc/iosf.h>
+#include <soc/itss.h>
+
+#define IOSF_ITSS_PORT_ID	0xd0
+#define ITSS_MAX_IRQ		119
+#define IPC0			0x3200
+#define IRQS_PER_IPC		32
+
+void itss_set_irq_polarity(int irq, int active_low)
+{
+	uint32_t mask;
+	uint32_t val;
+	uint16_t reg;
+	const uint16_t port = IOSF_ITSS_PORT_ID;
+
+	if (irq < 0 || irq > ITSS_MAX_IRQ)
+		return;
+
+	reg = IPC0 + sizeof(uint32_t) * (irq / IRQS_PER_IPC);
+	mask = 1 << (irq % IRQS_PER_IPC);
+
+	val = iosf_read(port, reg);
+	val &= ~mask;
+	/* Setting the bit makes the IRQ active low. */
+	val |= active_low ? mask : 0;
+	iosf_write(port, reg, val);
+}