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