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    Subject[PATCH 3.11 074/272] ARM: at91: fix hanged boot due to early rtc-interrupt
    Date
    3.11.10.1 -stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Johan Hovold <jhovold@gmail.com>

    commit 6de714c21a8ea315fffba6a93bbe537f4c1bf4f0 upstream.

    Make sure the RTC-interrupts are masked at boot by adding a new helper
    function to be used at SOC-init.

    This fixes hanged boot on all AT91 SOCs with an RTC (but RM9200), for
    example, after a reset during an RTC-update or if an RTC-alarm goes off
    after shutdown (e.g. when using RTC wakeup).

    The RTC and RTT-peripherals are powered by backup power (VDDBU) (on all
    AT91 SOCs but RM9200) and are not reset on wake-up, user, watchdog or
    software reset. This means that their interrupts may be enabled during
    early boot if, for example, they where not disabled during a previous
    shutdown (e.g. due to a buggy driver or a non-clean shutdown such as a
    user reset). Furthermore, an RTC or RTT-alarm may also be active.

    The RTC and RTT-interrupts use the shared system-interrupt line, which
    is also used by the PIT, and if an interrupt occurs before a handler
    (e.g. RTC-driver) has been installed this leads to the system interrupt
    being disabled and prevents the system from booting.

    Note that when boot hangs due to an early RTC or RTT-interrupt, the only
    way to get the system to start again is to remove the backup power (e.g.
    battery) or to disable the interrupt manually from the bootloader. In
    particular, a user reset is not sufficient.

    Signed-off-by: Johan Hovold <jhovold@gmail.com>
    Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
    [ luis: backported to 3.11: adjusted context ]
    Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
    ---
    arch/arm/mach-at91/Makefile | 2 +-
    arch/arm/mach-at91/at91sam9g45.c | 2 ++
    arch/arm/mach-at91/at91sam9n12.c | 6 ++++
    arch/arm/mach-at91/at91sam9rl.c | 2 ++
    arch/arm/mach-at91/at91sam9x5.c | 6 ++++
    arch/arm/mach-at91/generic.h | 1 +
    arch/arm/mach-at91/include/mach/at91sam9n12.h | 5 +++
    arch/arm/mach-at91/include/mach/at91sam9x5.h | 5 +++
    arch/arm/mach-at91/include/mach/sama5d3.h | 5 +++
    arch/arm/mach-at91/sama5d3.c | 6 ++++
    arch/arm/mach-at91/sysirq_mask.c | 47 +++++++++++++++++++++++++++
    11 files changed, 86 insertions(+), 1 deletion(-)
    create mode 100644 arch/arm/mach-at91/sysirq_mask.c

    diff --git a/arch/arm/mach-at91/Makefile b/arch/arm/mach-at91/Makefile
    index 3b0a953..e0fda04 100644
    --- a/arch/arm/mach-at91/Makefile
    +++ b/arch/arm/mach-at91/Makefile
    @@ -2,7 +2,7 @@
    # Makefile for the linux kernel.
    #

    -obj-y := irq.o gpio.o setup.o
    +obj-y := irq.o gpio.o setup.o sysirq_mask.o
    obj-m :=
    obj-n :=
    obj- :=
    diff --git a/arch/arm/mach-at91/at91sam9g45.c b/arch/arm/mach-at91/at91sam9g45.c
    index 474ee04..ff662af 100644
    --- a/arch/arm/mach-at91/at91sam9g45.c
    +++ b/arch/arm/mach-at91/at91sam9g45.c
    @@ -377,6 +377,8 @@ static void __init at91sam9g45_initialize(void)
    arm_pm_idle = at91sam9_idle;
    arm_pm_restart = at91sam9g45_restart;

    + at91_sysirq_mask_rtc(AT91SAM9G45_BASE_RTC);
    +
    /* Register GPIO subsystem */
    at91_gpio_init(at91sam9g45_gpio, 5);
    }
    diff --git a/arch/arm/mach-at91/at91sam9n12.c b/arch/arm/mach-at91/at91sam9n12.c
    index c7d670d..4d6001c 100644
    --- a/arch/arm/mach-at91/at91sam9n12.c
    +++ b/arch/arm/mach-at91/at91sam9n12.c
    @@ -223,7 +223,13 @@ static void __init at91sam9n12_map_io(void)
    at91_init_sram(0, AT91SAM9N12_SRAM_BASE, AT91SAM9N12_SRAM_SIZE);
    }

    +static void __init at91sam9n12_initialize(void)
    +{
    + at91_sysirq_mask_rtc(AT91SAM9N12_BASE_RTC);
    +}
    +
    AT91_SOC_START(at91sam9n12)
    .map_io = at91sam9n12_map_io,
    .register_clocks = at91sam9n12_register_clocks,
    + .init = at91sam9n12_initialize,
    AT91_SOC_END
    diff --git a/arch/arm/mach-at91/at91sam9rl.c b/arch/arm/mach-at91/at91sam9rl.c
    index d4ec0d9..b5a8c9d 100644
    --- a/arch/arm/mach-at91/at91sam9rl.c
    +++ b/arch/arm/mach-at91/at91sam9rl.c
    @@ -294,6 +294,8 @@ static void __init at91sam9rl_initialize(void)
    arm_pm_idle = at91sam9_idle;
    arm_pm_restart = at91sam9_alt_restart;

    + at91_sysirq_mask_rtc(AT91SAM9RL_BASE_RTC);
    +
    /* Register GPIO subsystem */
    at91_gpio_init(at91sam9rl_gpio, 4);
    }
    diff --git a/arch/arm/mach-at91/at91sam9x5.c b/arch/arm/mach-at91/at91sam9x5.c
    index 916e5a1..e8a2e07 100644
    --- a/arch/arm/mach-at91/at91sam9x5.c
    +++ b/arch/arm/mach-at91/at91sam9x5.c
    @@ -322,6 +322,11 @@ static void __init at91sam9x5_map_io(void)
    at91_init_sram(0, AT91SAM9X5_SRAM_BASE, AT91SAM9X5_SRAM_SIZE);
    }

    +static void __init at91sam9x5_initialize(void)
    +{
    + at91_sysirq_mask_rtc(AT91SAM9X5_BASE_RTC);
    +}
    +
    /* --------------------------------------------------------------------
    * Interrupt initialization
    * -------------------------------------------------------------------- */
    @@ -329,4 +334,5 @@ static void __init at91sam9x5_map_io(void)
    AT91_SOC_START(at91sam9x5)
    .map_io = at91sam9x5_map_io,
    .register_clocks = at91sam9x5_register_clocks,
    + .init = at91sam9x5_initialize,
    AT91_SOC_END
    diff --git a/arch/arm/mach-at91/generic.h b/arch/arm/mach-at91/generic.h
    index dc6e2f5..80269bd 100644
    --- a/arch/arm/mach-at91/generic.h
    +++ b/arch/arm/mach-at91/generic.h
    @@ -34,6 +34,7 @@ extern int __init at91_aic_of_init(struct device_node *node,
    struct device_node *parent);
    extern int __init at91_aic5_of_init(struct device_node *node,
    struct device_node *parent);
    +extern void __init at91_sysirq_mask_rtc(u32 rtc_base);


    /* Timer */
    diff --git a/arch/arm/mach-at91/include/mach/at91sam9n12.h b/arch/arm/mach-at91/include/mach/at91sam9n12.h
    index d374b87..0151bcf 100644
    --- a/arch/arm/mach-at91/include/mach/at91sam9n12.h
    +++ b/arch/arm/mach-at91/include/mach/at91sam9n12.h
    @@ -49,6 +49,11 @@
    #define AT91SAM9N12_BASE_USART3 0xf8028000

    /*
    + * System Peripherals
    + */
    +#define AT91SAM9N12_BASE_RTC 0xfffffeb0
    +
    +/*
    * Internal Memory.
    */
    #define AT91SAM9N12_SRAM_BASE 0x00300000 /* Internal SRAM base address */
    diff --git a/arch/arm/mach-at91/include/mach/at91sam9x5.h b/arch/arm/mach-at91/include/mach/at91sam9x5.h
    index c75ee19..2fc76c4 100644
    --- a/arch/arm/mach-at91/include/mach/at91sam9x5.h
    +++ b/arch/arm/mach-at91/include/mach/at91sam9x5.h
    @@ -55,6 +55,11 @@
    #define AT91SAM9X5_BASE_USART2 0xf8024000

    /*
    + * System Peripherals
    + */
    +#define AT91SAM9X5_BASE_RTC 0xfffffeb0
    +
    +/*
    * Internal Memory.
    */
    #define AT91SAM9X5_SRAM_BASE 0x00300000 /* Internal SRAM base address */
    diff --git a/arch/arm/mach-at91/include/mach/sama5d3.h b/arch/arm/mach-at91/include/mach/sama5d3.h
    index 6dc81ee..3abbc42 100644
    --- a/arch/arm/mach-at91/include/mach/sama5d3.h
    +++ b/arch/arm/mach-at91/include/mach/sama5d3.h
    @@ -65,6 +65,11 @@
    #define SAMA5D3_ID_IRQ0 47 /* Advanced Interrupt Controller (IRQ0) */

    /*
    + * System Peripherals
    + */
    +#define SAMA5D3_BASE_RTC 0xfffffeb0
    +
    +/*
    * Internal Memory
    */
    #define SAMA5D3_SRAM_BASE 0x00300000 /* Internal SRAM base address */
    diff --git a/arch/arm/mach-at91/sama5d3.c b/arch/arm/mach-at91/sama5d3.c
    index 4012797..3ea8642 100644
    --- a/arch/arm/mach-at91/sama5d3.c
    +++ b/arch/arm/mach-at91/sama5d3.c
    @@ -371,7 +371,13 @@ static void __init sama5d3_map_io(void)
    at91_init_sram(0, SAMA5D3_SRAM_BASE, SAMA5D3_SRAM_SIZE);
    }

    +static void __init sama5d3_initialize(void)
    +{
    + at91_sysirq_mask_rtc(SAMA5D3_BASE_RTC);
    +}
    +
    AT91_SOC_START(sama5d3)
    .map_io = sama5d3_map_io,
    .register_clocks = sama5d3_register_clocks,
    + .init = sama5d3_initialize,
    AT91_SOC_END
    diff --git a/arch/arm/mach-at91/sysirq_mask.c b/arch/arm/mach-at91/sysirq_mask.c
    new file mode 100644
    index 0000000..ee3e22c
    --- /dev/null
    +++ b/arch/arm/mach-at91/sysirq_mask.c
    @@ -0,0 +1,47 @@
    +/*
    + * 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 "generic.h"
    +
    +#define AT91_RTC_IDR 0x24 /* Interrupt Disable Register */
    +#define AT91_RTC_IMR 0x28 /* Interrupt Mask Register */
    +
    +void __init at91_sysirq_mask_rtc(u32 rtc_base)
    +{
    + void __iomem *base;
    + u32 mask;
    +
    + base = ioremap(rtc_base, 64);
    + if (!base)
    + return;
    +
    + mask = readl_relaxed(base + AT91_RTC_IMR);
    + if (mask) {
    + pr_info("AT91: Disabling rtc irq\n");
    + writel_relaxed(mask, base + AT91_RTC_IDR);
    + (void)readl_relaxed(base + AT91_RTC_IMR); /* flush */
    + }
    +
    + iounmap(base);
    +}
    --
    1.8.3.2


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