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    Subject[PATCH 3.11 075/272] ARM: at91: fix hanged boot due to early rtt-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 94c4c79f2f1acca6e69a50bff5a7d9027509c16b upstream.

    Make sure the RTT-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 RTT, for example, if an
    RTT-alarm goes off after a non-clean 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>
    Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
    ---
    arch/arm/mach-at91/at91sam9260.c | 2 ++
    arch/arm/mach-at91/at91sam9261.c | 2 ++
    arch/arm/mach-at91/at91sam9263.c | 3 +++
    arch/arm/mach-at91/at91sam9g45.c | 1 +
    arch/arm/mach-at91/at91sam9rl.c | 1 +
    arch/arm/mach-at91/generic.h | 1 +
    arch/arm/mach-at91/sysirq_mask.c | 24 ++++++++++++++++++++++++
    7 files changed, 34 insertions(+)

    diff --git a/arch/arm/mach-at91/at91sam9260.c b/arch/arm/mach-at91/at91sam9260.c
    index 5de6074..ae10d14 100644
    --- a/arch/arm/mach-at91/at91sam9260.c
    +++ b/arch/arm/mach-at91/at91sam9260.c
    @@ -349,6 +349,8 @@ static void __init at91sam9260_initialize(void)
    arm_pm_idle = at91sam9_idle;
    arm_pm_restart = at91sam9_alt_restart;

    + at91_sysirq_mask_rtt(AT91SAM9260_BASE_RTT);
    +
    /* Register GPIO subsystem */
    at91_gpio_init(at91sam9260_gpio, 3);
    }
    diff --git a/arch/arm/mach-at91/at91sam9261.c b/arch/arm/mach-at91/at91sam9261.c
    index 0e07932..e761e74 100644
    --- a/arch/arm/mach-at91/at91sam9261.c
    +++ b/arch/arm/mach-at91/at91sam9261.c
    @@ -291,6 +291,8 @@ static void __init at91sam9261_initialize(void)
    arm_pm_idle = at91sam9_idle;
    arm_pm_restart = at91sam9_alt_restart;

    + at91_sysirq_mask_rtt(AT91SAM9261_BASE_RTT);
    +
    /* Register GPIO subsystem */
    at91_gpio_init(at91sam9261_gpio, 3);
    }
    diff --git a/arch/arm/mach-at91/at91sam9263.c b/arch/arm/mach-at91/at91sam9263.c
    index 6ce7d18..e6fed62 100644
    --- a/arch/arm/mach-at91/at91sam9263.c
    +++ b/arch/arm/mach-at91/at91sam9263.c
    @@ -328,6 +328,9 @@ static void __init at91sam9263_initialize(void)
    arm_pm_idle = at91sam9_idle;
    arm_pm_restart = at91sam9_alt_restart;

    + at91_sysirq_mask_rtt(AT91SAM9263_BASE_RTT0);
    + at91_sysirq_mask_rtt(AT91SAM9263_BASE_RTT1);
    +
    /* Register GPIO subsystem */
    at91_gpio_init(at91sam9263_gpio, 5);
    }
    diff --git a/arch/arm/mach-at91/at91sam9g45.c b/arch/arm/mach-at91/at91sam9g45.c
    index ff662af..9f7a97c 100644
    --- a/arch/arm/mach-at91/at91sam9g45.c
    +++ b/arch/arm/mach-at91/at91sam9g45.c
    @@ -378,6 +378,7 @@ static void __init at91sam9g45_initialize(void)
    arm_pm_restart = at91sam9g45_restart;

    at91_sysirq_mask_rtc(AT91SAM9G45_BASE_RTC);
    + at91_sysirq_mask_rtt(AT91SAM9G45_BASE_RTT);

    /* Register GPIO subsystem */
    at91_gpio_init(at91sam9g45_gpio, 5);
    diff --git a/arch/arm/mach-at91/at91sam9rl.c b/arch/arm/mach-at91/at91sam9rl.c
    index b5a8c9d..301e172 100644
    --- a/arch/arm/mach-at91/at91sam9rl.c
    +++ b/arch/arm/mach-at91/at91sam9rl.c
    @@ -295,6 +295,7 @@ static void __init at91sam9rl_initialize(void)
    arm_pm_restart = at91sam9_alt_restart;

    at91_sysirq_mask_rtc(AT91SAM9RL_BASE_RTC);
    + at91_sysirq_mask_rtt(AT91SAM9RL_BASE_RTT);

    /* Register GPIO subsystem */
    at91_gpio_init(at91sam9rl_gpio, 4);
    diff --git a/arch/arm/mach-at91/generic.h b/arch/arm/mach-at91/generic.h
    index 80269bd..26dee3c 100644
    --- a/arch/arm/mach-at91/generic.h
    +++ b/arch/arm/mach-at91/generic.h
    @@ -35,6 +35,7 @@ extern int __init at91_aic_of_init(struct device_node *node,
    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);
    +extern void __init at91_sysirq_mask_rtt(u32 rtt_base);


    /* Timer */
    diff --git a/arch/arm/mach-at91/sysirq_mask.c b/arch/arm/mach-at91/sysirq_mask.c
    index ee3e22c..2ba694f 100644
    --- a/arch/arm/mach-at91/sysirq_mask.c
    +++ b/arch/arm/mach-at91/sysirq_mask.c
    @@ -21,6 +21,7 @@
    */

    #include <linux/io.h>
    +#include <mach/at91_rtt.h>

    #include "generic.h"

    @@ -45,3 +46,26 @@ void __init at91_sysirq_mask_rtc(u32 rtc_base)

    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);
    +}
    --
    1.8.3.2


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