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 first patch fixes this very general case of RTC-wake up after a clean shutdown in the RTC-driver and is marked for stable as it is perfectly straight-forward. [ Note that the other, RTT-based, AT91 RTC-driver already disables its interrupts at shutdown. ] 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 propose that arch-code should mask the relevant interrupts before enabling the system interrupt at early boot, and this is what the fifth patch does. To access the RTC-registers I choose to revert a recent patch that moved the register definitions to drivers/rtc. Arguably, the relevant interrupts could also be disabled in bootloaders, but I suggest fixing it in the kernel once and for all. The patches have been tested on at91sam9263 and at91sam9g45 (non-DT), and compile-tested for the other SOCs and DT. Johan v2: - add DT-support - make sys_irq_mask non-mandatory Johan Hovold (5): ARM: at91/rtc: fix boot after RTC wake-up ARM: at91/dts: add RTC nodes ARM: at91/dts: add RTT nodes Revert "arm: at91: move at91rm9200 rtc header in drivers/rtc" ARM: at91: fix hanged boot arch/arm/boot/dts/at91rm9200.dtsi | 5 ++ arch/arm/boot/dts/at91sam9260.dtsi | 5 ++ arch/arm/boot/dts/at91sam9263.dtsi | 10 ++++ arch/arm/boot/dts/at91sam9g45.dtsi | 10 ++++ arch/arm/boot/dts/at91sam9n12.dtsi | 5 ++ arch/arm/boot/dts/at91sam9x5.dtsi | 5 ++ arch/arm/mach-at91/at91sam9260.c | 6 ++ arch/arm/mach-at91/at91sam9261.c | 6 ++ arch/arm/mach-at91/at91sam9263.c | 7 +++ arch/arm/mach-at91/at91sam9g45.c | 7 +++ arch/arm/mach-at91/at91sam9rl.c | 7 +++ arch/arm/mach-at91/generic.h | 2 + arch/arm/mach-at91/include/mach/at91_rtc.h | 75 +++++++++++++++++++++++++ arch/arm/mach-at91/setup.c | 88 ++++++++++++++++++++++++++++++ arch/arm/mach-at91/soc.h | 1 + drivers/rtc/rtc-at91rm9200.c | 11 +++- drivers/rtc/rtc-at91rm9200.h | 75 ------------------------- 17 files changed, 249 insertions(+), 76 deletions(-) create mode 100644 arch/arm/mach-at91/include/mach/at91_rtc.h delete mode 100644 drivers/rtc/rtc-at91rm9200.h -- 1.8.1.5 -- 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/
