arch/arm/mach-at91/sysirq_mask.c

   1 /*
   2  * sysirq_mask.c - System-interrupt masking
   3  *
   4  * Copyright (C) 2013 Johan Hovold <jhovold@gmail.com>
   5  *
   6  * Functions to disable system interrupts from backup-powered peripherals.
   7  *
   8  * The RTC and RTT-peripherals are generally powered by backup power (VDDBU)
   9  * and are not reset on wake-up, user, watchdog or software reset. This means
  10  * that their interrupts may be enabled during early boot (e.g. after a user
  11  * reset).
  12  *
  13  * As the RTC and RTT share the system-interrupt line with the PIT, an
  14  * interrupt occurring before a handler has been installed would lead to the
  15  * system interrupt being disabled and prevent the system from booting.
  16  *
  17  * This program is free software; you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License as published by
  19  * the Free Software Foundation; either version 2 of the License, or
  20  * (at your option) any later version.
  21  */
  22
  23 #include <linux/io.h>
  24 #include <mach/at91_rtt.h>
  25
  26 #include "generic.h"
  27
  28 #define AT91_RTC_IDR    0x24    /* Interrupt Disable Register */
  29 #define AT91_RTC_IMR    0x28    /* Interrupt Mask Register */
  30
  31 void __init at91_sysirq_mask_rtc(u32 rtc_base)
  32 {
  33         void __iomem *base;
  34         u32 mask;
  35
  36         base = ioremap(rtc_base, 64);
  37         if (!base)
  38                 return;
  39
  40         mask = readl_relaxed(base + AT91_RTC_IMR);
  41         if (mask) {
  42                 pr_info("AT91: Disabling rtc irq\n");
  43                 writel_relaxed(mask, base + AT91_RTC_IDR);
  44                 (void)readl_relaxed(base + AT91_RTC_IMR);       /* flush */
  45         }
  46
  47         iounmap(base);
  48 }
  49
  50 void __init at91_sysirq_mask_rtt(u32 rtt_base)
  51 {
  52         void __iomem *base;
  53         void __iomem *reg;
  54         u32 mode;
  55
  56         base = ioremap(rtt_base, 16);
  57         if (!base)
  58                 return;
  59
  60         reg = base + AT91_RTT_MR;
  61
  62         mode = readl_relaxed(reg);
  63         if (mode & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN)) {
  64                 pr_info("AT91: Disabling rtt irq\n");
  65                 mode &= ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
  66                 writel_relaxed(mode, reg);
  67                 (void)readl_relaxed(reg);                       /* flush */
  68         }
  69
  70         iounmap(base);
  71 }