From 94c4c79f2f1acca6e69a50bff5a7d9027509c16b Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 16 Oct 2013 11:56:15 +0200 Subject: [PATCH] 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/at91sam9260.c | 2 ++ arch/arm/mach-at91/at91sam9261.c | 2 ++ arch/arm/mach-at91/at91sam9263.c | 3 +++ arch/arm/mach-at91/at91sam9g45.c | 1 + arch/arm/mach-at91/at91sam9rl.c | 1 + arch/arm/mach-at91/generic.h | 1 + arch/arm/mach-at91/sysirq_mask.c | 24 ++++++++++++++++++++++++ 7 files changed, 34 insertions(+) diff --git a/arch/arm/mach-at91/at91sam9260.c b/arch/arm/mach-at91/at91sam9260.c index 5de6074b4f4f..ae10d14de700 100644 --- a/arch/arm/mach-at91/at91sam9260.c +++ b/arch/arm/mach-at91/at91sam9260.c @@ -349,6 +349,8 @@ static void __init at91sam9260_initialize(void) arm_pm_idle = at91sam9_idle; arm_pm_restart = at91sam9_alt_restart; + at91_sysirq_mask_rtt(AT91SAM9260_BASE_RTT); + /* Register GPIO subsystem */ at91_gpio_init(at91sam9260_gpio, 3); } diff --git a/arch/arm/mach-at91/at91sam9261.c b/arch/arm/mach-at91/at91sam9261.c index 0e0793241ab7..e761e74ac64b 100644 --- a/arch/arm/mach-at91/at91sam9261.c +++ b/arch/arm/mach-at91/at91sam9261.c @@ -291,6 +291,8 @@ static void __init at91sam9261_initialize(void) arm_pm_idle = at91sam9_idle; arm_pm_restart = at91sam9_alt_restart; + at91_sysirq_mask_rtt(AT91SAM9261_BASE_RTT); + /* Register GPIO subsystem */ at91_gpio_init(at91sam9261_gpio, 3); } diff --git a/arch/arm/mach-at91/at91sam9263.c b/arch/arm/mach-at91/at91sam9263.c index 6ce7d1850893..e6fed6253a7f 100644 --- a/arch/arm/mach-at91/at91sam9263.c +++ b/arch/arm/mach-at91/at91sam9263.c @@ -328,6 +328,9 @@ static void __init at91sam9263_initialize(void) arm_pm_idle = at91sam9_idle; arm_pm_restart = at91sam9_alt_restart; + at91_sysirq_mask_rtt(AT91SAM9263_BASE_RTT0); + at91_sysirq_mask_rtt(AT91SAM9263_BASE_RTT1); + /* Register GPIO subsystem */ at91_gpio_init(at91sam9263_gpio, 5); } 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); diff --git a/arch/arm/mach-at91/at91sam9rl.c b/arch/arm/mach-at91/at91sam9rl.c index b5a8c9d81bc8..301e1728d353 100644 --- a/arch/arm/mach-at91/at91sam9rl.c +++ b/arch/arm/mach-at91/at91sam9rl.c @@ -295,6 +295,7 @@ static void __init at91sam9rl_initialize(void) arm_pm_restart = at91sam9_alt_restart; at91_sysirq_mask_rtc(AT91SAM9RL_BASE_RTC); + at91_sysirq_mask_rtt(AT91SAM9RL_BASE_RTT); /* Register GPIO subsystem */ at91_gpio_init(at91sam9rl_gpio, 4); diff --git a/arch/arm/mach-at91/generic.h b/arch/arm/mach-at91/generic.h index 80269bda0dd7..26dee3ce9397 100644 --- a/arch/arm/mach-at91/generic.h +++ b/arch/arm/mach-at91/generic.h @@ -35,6 +35,7 @@ extern int __init at91_aic_of_init(struct device_node *node, extern int __init at91_aic5_of_init(struct device_node *node, struct device_node *parent); extern void __init at91_sysirq_mask_rtc(u32 rtc_base); +extern void __init at91_sysirq_mask_rtt(u32 rtt_base); /* Timer */ diff --git a/arch/arm/mach-at91/sysirq_mask.c b/arch/arm/mach-at91/sysirq_mask.c index ee3e22c66ce8..2ba694f9626b 100644 --- a/arch/arm/mach-at91/sysirq_mask.c +++ b/arch/arm/mach-at91/sysirq_mask.c @@ -21,6 +21,7 @@ */ #include +#include #include "generic.h" @@ -45,3 +46,26 @@ void __init at91_sysirq_mask_rtc(u32 rtc_base) iounmap(base); } + +void __init at91_sysirq_mask_rtt(u32 rtt_base) +{ + void __iomem *base; + void __iomem *reg; + u32 mode; + + base = ioremap(rtt_base, 16); + if (!base) + return; + + reg = base + AT91_RTT_MR; + + mode = readl_relaxed(reg); + if (mode & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN)) { + pr_info("AT91: Disabling rtt irq\n"); + mode &= ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN); + writel_relaxed(mode, reg); + (void)readl_relaxed(reg); /* flush */ + } + + iounmap(base); +}