1 files changed, 47 insertions, 0 deletions
diff --git a/include/mach/at91/at91_rtt.h b/include/mach/at91/at91_rtt.h
new file mode 100644
index 0000000000..b4197665dd
--- /dev/null
+++ b/include/mach/at91/at91_rtt.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* SPDX-FileCopyrightText: 2007 Andrew Victor */
+/* SPDX-FileCopyrightText: 2007 Atmel Corporation */
+
+/*
+ * arch/arm/mach-at91/include/mach/at91_rtt.h
+ *
+ * Real-time Timer (RTT) - System peripherals regsters.
+ * Based on AT91SAM9261 datasheet revision D.
+ */
+
+#ifndef AT91_RTT_H
+#define AT91_RTT_H
+
+#include <io.h>
+
+#define AT91_RTT_MR		0x00			/* Real-time Mode Register */
+#define		AT91_RTT_RTPRES		(0xffff << 0)		/* Real-time Timer Prescaler Value */
+#define		AT91_RTT_ALMIEN		(1 << 16)		/* Alarm Interrupt Enable */
+#define		AT91_RTT_RTTINCIEN	(1 << 17)		/* Real Time Timer Increment Interrupt Enable */
+#define		AT91_RTT_RTTRST		(1 << 18)		/* Real Time Timer Restart */
+
+#define AT91_RTT_AR		0x04			/* Real-time Alarm Register */
+#define		AT91_RTT_ALMV		(0xffffffff)		/* Alarm Value */
+
+#define AT91_RTT_VR		0x08			/* Real-time Value Register */
+#define		AT91_RTT_CRTV		(0xffffffff)		/* Current Real-time Value */
+
+#define AT91_RTT_SR		0x0c			/* Real-time Status Register */
+#define		AT91_RTT_ALMS		(1 << 0)		/* Real-time Alarm Status */
+#define		AT91_RTT_RTTINC		(1 << 1)		/* Real-time Timer Increment */
+
+
+/*
+ * As the RTT is powered by the backup power so if the interrupt
+ * is still on when the kernel start, the kernel will end up with
+ * dead lock interrupt that it can not clear. Because the interrupt line is
+ * shared with the basic timer (PIT) on AT91_ID_SYS.
+ */
+static inline void at91_rtt_irq_fixup(void *base)
+{
+	void __iomem *reg = base + AT91_RTT_MR;
+	u32 mr = readl(reg);
+
+	writel(mr & ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN), reg);
+}
+#endif