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Commit 6de714c2 authored by Johan Hovold's avatar Johan Hovold Committed by Nicolas Ferre
Browse files

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: default avatarJohan Hovold <jhovold@gmail.com>
Signed-off-by: default avatarNicolas Ferre <nicolas.ferre@atmel.com>
Cc: stable@vger.kernel.org # 3.11.x
parent 15c03dd4

arch/arm/mach-at91/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
# Makefile for the linux kernel.

#



obj-y		:= irq.o gpio.o setup.o

obj-y		:= irq.o gpio.o setup.o sysirq_mask.o

obj-m		:=

obj-n		:=

obj-		:=

arch/arm/mach-at91/at91sam9g45.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

}

arch/arm/mach-at91/at91sam9n12.c

+6 −0
Original line number Diff line number Diff line
@@ -223,7 +223,13 @@ static void __init at91sam9n12_map_io(void) 
	at91_init_sram(0, AT91SAM9N12_SRAM_BASE, AT91SAM9N12_SRAM_SIZE);

}



static void __init at91sam9n12_initialize(void)

{

	at91_sysirq_mask_rtc(AT91SAM9N12_BASE_RTC);

}



AT91_SOC_START(at91sam9n12)

	.map_io = at91sam9n12_map_io,

	.register_clocks = at91sam9n12_register_clocks,

	.init = at91sam9n12_initialize,

AT91_SOC_END

arch/arm/mach-at91/at91sam9rl.c

+2 −0
Original line number Diff line number Diff line
@@ -294,6 +294,8 @@ static void __init at91sam9rl_initialize(void) 
	arm_pm_idle = at91sam9_idle;

	arm_pm_restart = at91sam9_alt_restart;



	at91_sysirq_mask_rtc(AT91SAM9RL_BASE_RTC);



	/* Register GPIO subsystem */

	at91_gpio_init(at91sam9rl_gpio, 4);

}

arch/arm/mach-at91/at91sam9x5.c

+6 −0
Original line number Diff line number Diff line
@@ -322,6 +322,11 @@ static void __init at91sam9x5_map_io(void) 
	at91_init_sram(0, AT91SAM9X5_SRAM_BASE, AT91SAM9X5_SRAM_SIZE);

}



static void __init at91sam9x5_initialize(void)

{

	at91_sysirq_mask_rtc(AT91SAM9X5_BASE_RTC);

}



/* --------------------------------------------------------------------

 *  Interrupt initialization

 * -------------------------------------------------------------------- */
@@ -329,4 +334,5 @@ static void __init at91sam9x5_map_io(void) 
AT91_SOC_START(at91sam9x5)

	.map_io = at91sam9x5_map_io,

	.register_clocks = at91sam9x5_register_clocks,

	.init = at91sam9x5_initialize,

AT91_SOC_END