These patches fix a few severe issues affecting most AT91 SOCs where boot can hang after a non-general reset, and where the only way to get the system booting again is to do a general reset -- something which could require physically removing any backup battery.
The problems stem from the fact that the RTC and RTT-peripherals are powered by backup power (VDDBU) and are not reset on wake-up, user, watchdog or software reset. Consequently, RTC and RTT-alarms and their interrupts may be enabled at boot, leading to a system lock-up when an interrupt arrives on the shared system-interrupt line before the appropriate handler (e.g. RTC-driver) has been installed. The easiest way to trigger this is to simply wake up from an RTC-alarm on at91sam9g45. The RTC-driver currently does not disable interrupts at shutdown so even after a clean shut-down the system will always hang after waking up. The more general problem can be triggered, for example, by doing a user-reset while updating the RTC-time or if an RTC or RTT-alarm goes off after a non-clean shutdown. To fix this I add two helper functions to be called called by arch-code to mask the relevant interrupts before enabling the system interrupt at early boot. The patches have been tested on at91sam9g45 and compile-tested for the other SOCs. Johan v2: - add DT-support - make sys_irq_mask non-mandatory v3 - rebase on v3.12-rc5 - drop DT-support (interrupt masking is needed even if RTC or RTT nodes are missing) - drop dedicated SOC-initialiser and call helpers directly from init - drop revert-patch of move of RTC-register definitions to drivers/ and copy the two needed definitions instead - move helper functions from setup.c to a separate file - add fix for new sama5d3 SOC - add a register read back to make sure write has reached the devices - split fix in two patches for RTC and RTT, respectively Johan Hovold (3): ARM: at91: fix hanged boot due to early rtc-interrupt ARM: at91: fix hanged boot due to early rtt-interrupt ARM: at91/rtc: disable interrupts at shutdown arch/arm/mach-at91/Makefile | 2 +- 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 | 3 ++ arch/arm/mach-at91/at91sam9n12.c | 6 +++ arch/arm/mach-at91/at91sam9rl.c | 3 ++ arch/arm/mach-at91/at91sam9x5.c | 6 +++ arch/arm/mach-at91/generic.h | 2 + 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 | 71 +++++++++++++++++++++++++++ drivers/rtc/rtc-at91rm9200.c | 9 ++++ 15 files changed, 129 insertions(+), 1 deletion(-) create mode 100644 arch/arm/mach-at91/sysirq_mask.c -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/