From 501d70383aa9ffc78b41aa7e74f6b0254c7c731c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Mon, 21 Sep 2009 09:30:09 +0200 Subject: [PATCH 1/2] arm/at91: Don't disable irqs in set_next_event and set_mode callbacks MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit on AT91 the timer irq is shared, so the handler might be entered without irqs being disabled. Though this should not happen as the timer irq is registered early, there have been some reports on the mailing list. To make debugging that problem easier next time it pops up a WARN_ON_ONCE is added to the handler if irqs are not off. Signed-off-by: Uwe Kleine-König --- arch/arm/mach-at91/at91rm9200_time.c | 20 ++++++-------------- arch/arm/mach-at91/at91sam926x_time.c | 11 ++++++----- 2 files changed, 12 insertions(+), 19 deletions(-) diff --git a/arch/arm/mach-at91/at91rm9200_time.c b/arch/arm/mach-at91/at91rm9200_time.c index 309f3511aa20..2500f41d8d2d 100644 --- a/arch/arm/mach-at91/at91rm9200_time.c +++ b/arch/arm/mach-at91/at91rm9200_time.c @@ -58,6 +58,12 @@ static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id) { u32 sr = at91_sys_read(AT91_ST_SR) & irqmask; + /* + * irqs should be disabled here, but as the irq is shared they are only + * guaranteed to be off if the timer irq is registered first. + */ + WARN_ON_ONCE(!irqs_disabled()); + /* simulate "oneshot" timer with alarm */ if (sr & AT91_ST_ALMS) { clkevt.event_handler(&clkevt); @@ -132,24 +138,11 @@ clkevt32k_mode(enum clock_event_mode mode, struct clock_event_device *dev) static int clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev) { - unsigned long flags; u32 alm; int status = 0; BUG_ON(delta < 2); - /* Use "raw" primitives so we behave correctly on RT kernels. */ - raw_local_irq_save(flags); - - /* - * According to Thomas Gleixner irqs are already disabled here. Simply - * removing raw_local_irq_save above (and the matching - * raw_local_irq_restore) was not accepted. See - * http://thread.gmane.org/gmane.linux.ports.arm.kernel/41174 - * So for now (2008-11-20) just warn once if irqs were not disabled ... - */ - WARN_ON_ONCE(!raw_irqs_disabled_flags(flags)); - /* The alarm IRQ uses absolute time (now+delta), not the relative * time (delta) in our calling convention. Like all clockevents * using such "match" hardware, we have a race to defend against. @@ -169,7 +162,6 @@ clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev) alm += delta; at91_sys_write(AT91_ST_RTAR, alm); - raw_local_irq_restore(flags); return status; } diff --git a/arch/arm/mach-at91/at91sam926x_time.c b/arch/arm/mach-at91/at91sam926x_time.c index 4bd56aee4370..608a63240b64 100644 --- a/arch/arm/mach-at91/at91sam926x_time.c +++ b/arch/arm/mach-at91/at91sam926x_time.c @@ -62,16 +62,12 @@ static struct clocksource pit_clk = { static void pit_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev) { - unsigned long flags; - switch (mode) { case CLOCK_EVT_MODE_PERIODIC: - /* update clocksource counter, then enable the IRQ */ - raw_local_irq_save(flags); + /* update clocksource counter */ pit_cnt += pit_cycle * PIT_PICNT(at91_sys_read(AT91_PIT_PIVR)); at91_sys_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN | AT91_PIT_PITIEN); - raw_local_irq_restore(flags); break; case CLOCK_EVT_MODE_ONESHOT: BUG(); @@ -100,6 +96,11 @@ static struct clock_event_device pit_clkevt = { */ static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id) { + /* + * irqs should be disabled here, but as the irq is shared they are only + * guaranteed to be off if the timer irq is registered first. + */ + WARN_ON_ONCE(!irqs_disabled()); /* The PIT interrupt may be disabled, and is shared */ if ((pit_clkevt.mode == CLOCK_EVT_MODE_PERIODIC) From a602f0f2f04f150fa1f7312b9e601e8e1a5afe10 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Thu, 17 Dec 2009 12:43:29 +0100 Subject: [PATCH 2/2] arm/{pxa,sa1100,nomadik}: Don't disable irqs in set_next_event and set_mode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit These functions are called with irqs already off. This commit removes the calls to raw_local_irq_save and raw_local_irq_restore on platforms that don't have to use a shared interrupt for their timekeeping. Signed-off-by: Uwe Kleine-König --- arch/arm/mach-pxa/time.c | 10 +--------- arch/arm/mach-sa1100/time.c | 8 +------- arch/arm/plat-nomadik/timer.c | 9 +-------- 3 files changed, 3 insertions(+), 24 deletions(-) diff --git a/arch/arm/mach-pxa/time.c b/arch/arm/mach-pxa/time.c index 750c448db672..293e40aeaf29 100644 --- a/arch/arm/mach-pxa/time.c +++ b/arch/arm/mach-pxa/time.c @@ -76,14 +76,12 @@ pxa_ost0_interrupt(int irq, void *dev_id) static int pxa_osmr0_set_next_event(unsigned long delta, struct clock_event_device *dev) { - unsigned long flags, next, oscr; + unsigned long next, oscr; - raw_local_irq_save(flags); OIER |= OIER_E0; next = OSCR + delta; OSMR0 = next; oscr = OSCR; - raw_local_irq_restore(flags); return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0; } @@ -91,23 +89,17 @@ pxa_osmr0_set_next_event(unsigned long delta, struct clock_event_device *dev) static void pxa_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *dev) { - unsigned long irqflags; - switch (mode) { case CLOCK_EVT_MODE_ONESHOT: - raw_local_irq_save(irqflags); OIER &= ~OIER_E0; OSSR = OSSR_M0; - raw_local_irq_restore(irqflags); break; case CLOCK_EVT_MODE_UNUSED: case CLOCK_EVT_MODE_SHUTDOWN: /* initializing, released, or preparing for suspend */ - raw_local_irq_save(irqflags); OIER &= ~OIER_E0; OSSR = OSSR_M0; - raw_local_irq_restore(irqflags); break; case CLOCK_EVT_MODE_RESUME: diff --git a/arch/arm/mach-sa1100/time.c b/arch/arm/mach-sa1100/time.c index b9cbb56d6e9d..74b6e0e570b6 100644 --- a/arch/arm/mach-sa1100/time.c +++ b/arch/arm/mach-sa1100/time.c @@ -35,14 +35,12 @@ static irqreturn_t sa1100_ost0_interrupt(int irq, void *dev_id) static int sa1100_osmr0_set_next_event(unsigned long delta, struct clock_event_device *c) { - unsigned long flags, next, oscr; + unsigned long next, oscr; - raw_local_irq_save(flags); OIER |= OIER_E0; next = OSCR + delta; OSMR0 = next; oscr = OSCR; - raw_local_irq_restore(flags); return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0; } @@ -50,16 +48,12 @@ sa1100_osmr0_set_next_event(unsigned long delta, struct clock_event_device *c) static void sa1100_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *c) { - unsigned long flags; - switch (mode) { case CLOCK_EVT_MODE_ONESHOT: case CLOCK_EVT_MODE_UNUSED: case CLOCK_EVT_MODE_SHUTDOWN: - raw_local_irq_save(flags); OIER &= ~OIER_E0; OSSR = OSSR_M0; - raw_local_irq_restore(flags); break; case CLOCK_EVT_MODE_RESUME: diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c index 62f18ad43a28..fa7cb3a57cbf 100644 --- a/arch/arm/plat-nomadik/timer.c +++ b/arch/arm/plat-nomadik/timer.c @@ -49,24 +49,17 @@ static struct clocksource nmdk_clksrc = { static void nmdk_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev) { - unsigned long flags; - switch (mode) { case CLOCK_EVT_MODE_PERIODIC: - /* enable interrupts -- and count current value? */ - raw_local_irq_save(flags); + /* count current value? */ writel(readl(mtu_base + MTU_IMSC) | 1, mtu_base + MTU_IMSC); - raw_local_irq_restore(flags); break; case CLOCK_EVT_MODE_ONESHOT: BUG(); /* Not supported, yet */ /* FALLTHROUGH */ case CLOCK_EVT_MODE_SHUTDOWN: case CLOCK_EVT_MODE_UNUSED: - /* disable irq */ - raw_local_irq_save(flags); writel(readl(mtu_base + MTU_IMSC) & ~1, mtu_base + MTU_IMSC); - raw_local_irq_restore(flags); break; case CLOCK_EVT_MODE_RESUME: break;