/* * 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 */ #define AT91_RTC_IRQ_MASK 0x1f /* Available IRQs mask */ void __init at91_sysirq_mask_rtc(u32 rtc_base) { void __iomem *base; base = ioremap(rtc_base, 64); if (!base) return; /* * sam9x5 SoCs have the following errata: * "RTC: Interrupt Mask Register cannot be used * Interrupt Mask Register read always returns 0." * * Hence we're not relying on IMR values to disable * interrupts. */ writel_relaxed(AT91_RTC_IRQ_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); }