From 6de714c21a8ea315fffba6a93bbe537f4c1bf4f0 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 16 Oct 2013 11:56:14 +0200 Subject: ARM: at91: fix hanged boot due to early rtc-interrupt 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 Signed-off-by: Nicolas Ferre Cc: stable@vger.kernel.org # 3.11.x --- arch/arm/mach-at91/at91sam9g45.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/arm/mach-at91/at91sam9g45.c') diff --git a/arch/arm/mach-at91/at91sam9g45.c b/arch/arm/mach-at91/at91sam9g45.c index 474ee04d24b9..ff662af77fee 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); } -- cgit From 94c4c79f2f1acca6e69a50bff5a7d9027509c16b Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 16 Oct 2013 11:56:15 +0200 Subject: ARM: at91: fix hanged boot due to early rtt-interrupt 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 Signed-off-by: Nicolas Ferre Cc: stable@vger.kernel.org # 3.11.x --- arch/arm/mach-at91/at91sam9g45.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/arm/mach-at91/at91sam9g45.c') diff --git a/arch/arm/mach-at91/at91sam9g45.c b/arch/arm/mach-at91/at91sam9g45.c index ff662af77fee..9f7a97c84c12 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); -- cgit