From: jhovold@gmail.com (Johan Hovold)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 0/3] ARM: at91: fix hanged boot
Date: Fri, 8 Mar 2013 13:51:40 +0100 [thread overview]
Message-ID: <1362747103-21445-1-git-send-email-jhovold@gmail.com> (raw)
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
at early boot, and this is what the third patch does. To access the
RTC-registers I choose to revert a recent patch that moved the register
definitions to drivers/rtc.
Arguably, the interrupts could also be disabled in bootloaders, but I
strongly suggest fixing it in the kernel once and for all. By adding a
new, mandatory AT91 SOC-initialiser (rather extending init) it will not
be overlooked when adding new SOCs either.
The patches have been tested on at91sam9263 and at91sam9g45, and
compile-tested for the other SOCs.
Johan
Johan Hovold (3):
ARM: at91/rtc: fix boot after RTC wake-up
Revert "arm: at91: move at91rm9200 rtc header in drivers/rtc"
ARM: at91: fix hanged boot
arch/arm/mach-at91/at91rm9200.c | 9 ++++
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/at91sam9n12.c | 6 +++
arch/arm/mach-at91/at91sam9rl.c | 7 +++
arch/arm/mach-at91/at91sam9x5.c | 6 +++
arch/arm/mach-at91/generic.h | 2 +
arch/arm/mach-at91/include/mach/at91_rtc.h | 75 +++++++++++++++++++++++++++
arch/arm/mach-at91/include/mach/at91sam9n12.h | 5 ++
arch/arm/mach-at91/include/mach/at91sam9x5.h | 5 ++
arch/arm/mach-at91/setup.c | 31 +++++++++++
arch/arm/mach-at91/soc.h | 1 +
drivers/rtc/rtc-at91rm9200.c | 11 +++-
drivers/rtc/rtc-at91rm9200.h | 75 ---------------------------
16 files changed, 183 insertions(+), 76 deletions(-)
create mode 100644 arch/arm/mach-at91/include/mach/at91_rtc.h
delete mode 100644 drivers/rtc/rtc-at91rm9200.h
--
1.8.1.1
next reply other threads:[~2013-03-08 12:51 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-08 12:51 Johan Hovold [this message]
2013-03-08 12:51 ` [PATCH 1/3] ARM: at91/rtc: fix boot after RTC wake-up Johan Hovold
2013-03-08 12:51 ` [PATCH 2/3] Revert "arm: at91: move at91rm9200 rtc header in drivers/rtc" Johan Hovold
2013-03-08 12:51 ` [PATCH 3/3] ARM: at91: fix hanged boot Johan Hovold
2013-03-08 16:02 ` [rtc-linux] " Jean-Christophe PLAGNIOL-VILLARD
2013-03-11 10:02 ` Johan Hovold
2013-03-11 11:06 ` Jean-Christophe PLAGNIOL-VILLARD
2013-03-11 18:06 ` Johan Hovold
2013-03-11 18:07 ` [PATCH v2 0/5] " Johan Hovold
2013-03-11 18:07 ` [PATCH v2 1/5] ARM: at91/rtc: fix boot after RTC wake-up Johan Hovold
2013-03-11 18:07 ` [PATCH v2 2/5] ARM: at91/dts: add RTC nodes Johan Hovold
2013-03-11 18:07 ` [PATCH v2 3/5] ARM: at91/dts: add RTT nodes Johan Hovold
2013-03-11 18:07 ` [PATCH v2 4/5] Revert "arm: at91: move at91rm9200 rtc header in drivers/rtc" Johan Hovold
2013-03-11 18:07 ` [PATCH v2 5/5] ARM: at91: fix hanged boot Johan Hovold
2013-04-11 15:55 ` [PATCH v2 0/5] " Johan Hovold
2013-04-11 16:54 ` [rtc-linux] " Jean-Christophe PLAGNIOL-VILLARD
2013-04-12 9:33 ` Johan Hovold
2013-04-12 12:09 ` Nicolas Ferre
2013-10-16 9:56 ` [PATCH v3 0/3] " Johan Hovold
2013-10-16 9:56 ` [PATCH v3 1/3] ARM: at91: fix hanged boot due to early rtc-interrupt Johan Hovold
2013-11-15 11:09 ` Nicolas Ferre
2013-10-16 9:56 ` [PATCH v3 2/3] ARM: at91: fix hanged boot due to early rtt-interrupt Johan Hovold
2013-11-15 11:10 ` Nicolas Ferre
2013-10-16 9:56 ` [PATCH v3 3/3] ARM: at91/rtc: disable interrupts at shutdown Johan Hovold
2013-11-15 10:43 ` Nicolas Ferre
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