diff options
Diffstat (limited to 'arch/arm/mach-at91/sysirq_mask.c')
-rw-r--r-- | arch/arm/mach-at91/sysirq_mask.c | 75 |
1 files changed, 75 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..f8bc3511a8c8 --- /dev/null +++ b/arch/arm/mach-at91/sysirq_mask.c @@ -0,0 +1,75 @@ +/* + * 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); +} |