76 lines
2 KiB
C
76 lines
2 KiB
C
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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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#include <linux/io.h>
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#include <mach/at91_rtt.h>
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#include "generic.h"
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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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#define AT91_RTC_IRQ_MASK 0x1f /* Available IRQs mask */
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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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base = ioremap(rtc_base, 64);
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if (!base)
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return;
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/*
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* sam9x5 SoCs have the following errata:
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* "RTC: Interrupt Mask Register cannot be used
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* Interrupt Mask Register read always returns 0."
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*
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* Hence we're not relying on IMR values to disable
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* interrupts.
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*/
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writel_relaxed(AT91_RTC_IRQ_MASK, base + AT91_RTC_IDR);
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(void)readl_relaxed(base + AT91_RTC_IMR); /* flush */
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iounmap(base);
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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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base = ioremap(rtt_base, 16);
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if (!base)
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return;
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reg = base + AT91_RTT_MR;
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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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iounmap(base);
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}
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