1 files changed, 71 insertions, 0 deletions

diff --git a/arch/arm/mach-at91/sysirq_mask.c b/arch/arm/mach-at91/sysirq_mask.c
new file mode 100644
index 000000000000..2ba694f9626b
--- /dev/null
+++ b/arch/arm/mach-at91/sysirq_mask.c
@@ -0,0 +1,71 @@
+/*
+ * sysirq_mask.c - System-interrupt masking
+ *
+ * Copyright (C) 2013 Johan Hovold <jhovold@gmail.com>
+ *
+ * Functions to disable system interrupts from backup-powered peripherals.
+ *
+ * The RTC and RTT-peripherals are generally powered by backup power (VDDBU)
+ * and are not reset on wake-up, user, watchdog or software reset. This means
+ * that their interrupts may be enabled during early boot (e.g. after a user
+ * reset).
+ *
+ * As the RTC and RTT share the system-interrupt line with the PIT, an
+ * interrupt occurring before a handler has been installed would lead to the
+ * system interrupt being disabled and prevent the system from booting.
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/io.h>
+#include <mach/at91_rtt.h>
+
+#include "generic.h"
+
+#define AT91_RTC_IDR    0x24    /* Interrupt Disable Register */
+#define AT91_RTC_IMR    0x28    /* Interrupt Mask Register */
+
+void __init at91_sysirq_mask_rtc(u32 rtc_base)
+{
+        void __iomem *base;
+        u32 mask;
+
+        base = ioremap(rtc_base, 64);
+        if (!base)
+                return;
+
+        mask = readl_relaxed(base + AT91_RTC_IMR);
+        if (mask) {
+                pr_info("AT91: Disabling rtc irq\n");
+                writel_relaxed(mask, base + AT91_RTC_IDR);
+                (void)readl_relaxed(base + AT91_RTC_IMR);       /* flush */
+        }
+
+        iounmap(base);
+}
+
+void __init at91_sysirq_mask_rtt(u32 rtt_base)
+{
+        void __iomem *base;
+        void __iomem *reg;
+        u32 mode;
+
+        base = ioremap(rtt_base, 16);
+        if (!base)
+                return;
+
+        reg = base + AT91_RTT_MR;
+
+        mode = readl_relaxed(reg);
+        if (mode & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN)) {
+                pr_info("AT91: Disabling rtt irq\n");
+                mode &= ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
+                writel_relaxed(mode, reg);
+                (void)readl_relaxed(reg);                       /* flush */
+        }
+
+        iounmap(base);
+}