From 737eb0301f296d55c22350c6968ff1ef51bacb5f Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Fri, 20 Feb 2015 14:53:46 +0000 Subject: genirq / PM: better describe IRQF_NO_SUSPEND semantics The IRQF_NO_SUSPEND flag is intended to be used for interrupts required to be enabled during the suspend-resume cycle. This mostly consists of IPIs and timer interrupts, potentially including chained irqchip interrupts if these are necessary to handle timers or IPIs. If an interrupt does not fall into one of the aforementioned categories, requesting it with IRQF_NO_SUSPEND is likely incorrect. Using IRQF_NO_SUSPEND does not guarantee that the interrupt can wake the system from a suspended state. For an interrupt to be able to trigger a wakeup, it may be necessary to program various components of the system. In these cases it is necessary to use {enable,disabled}_irq_wake. Unfortunately, several drivers assume that IRQF_NO_SUSPEND ensures that an IRQ can wake up the system, and the documentation can be read ambiguously w.r.t. this property. This patch updates the documentation regarding IRQF_NO_SUSPEND to make this caveat explicit, hopefully making future misuse rarer. Cleanup of existing misuse will occur as part of later patch series. Signed-off-by: Mark Rutland Acked-by: Peter Zijlstra (Intel) Signed-off-by: Rafael J. Wysocki --- Documentation/power/suspend-and-interrupts.txt | 6 ++++-- include/linux/interrupt.h | 4 +++- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/Documentation/power/suspend-and-interrupts.txt b/Documentation/power/suspend-and-interrupts.txt index 2f9c5a5fcb25..50493c9284b4 100644 --- a/Documentation/power/suspend-and-interrupts.txt +++ b/Documentation/power/suspend-and-interrupts.txt @@ -40,8 +40,10 @@ but also to IPIs and to some other special-purpose interrupts. The IRQF_NO_SUSPEND flag is used to indicate that to the IRQ subsystem when requesting a special-purpose interrupt. It causes suspend_device_irqs() to -leave the corresponding IRQ enabled so as to allow the interrupt to work all -the time as expected. +leave the corresponding IRQ enabled so as to allow the interrupt to work as +expected during the suspend-resume cycle, but does not guarantee that the +interrupt will wake the system from a suspended state -- for such cases it is +necessary to use enable_irq_wake(). Note that the IRQF_NO_SUSPEND flag affects the entire IRQ and not just one user of it. Thus, if the IRQ is shared, all of the interrupt handlers installed diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index d9b05b5bf8c7..606771c7cac2 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -52,7 +52,9 @@ * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished. * Used by threaded interrupts which need to keep the * irq line disabled until the threaded handler has been run. - * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend + * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend. Does not guarantee + * that this interrupt will wake the system from a suspended + * state. See Documentation/power/suspend-and-interrupts.txt * IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set * IRQF_NO_THREAD - Interrupt cannot be threaded * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device -- cgit v1.2.3 From 17f480342026e54000731acaa69bf32787ce46cb Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 27 Feb 2015 00:07:55 +0100 Subject: genirq / PM: Add flag for shared NO_SUSPEND interrupt lines It currently is required that all users of NO_SUSPEND interrupt lines pass the IRQF_NO_SUSPEND flag when requesting the IRQ or the WARN_ON_ONCE() in irq_pm_install_action() will trigger. That is done to warn about situations in which unprepared interrupt handlers may be run unnecessarily for suspended devices and may attempt to access those devices by mistake. However, it may cause drivers that have no technical reasons for using IRQF_NO_SUSPEND to set that flag just because they happen to share the interrupt line with something like a timer. Moreover, the generic handling of wakeup interrupts introduced by commit 9ce7a25849e8 (genirq: Simplify wakeup mechanism) only works for IRQs without any NO_SUSPEND users, so the drivers of wakeup devices needing to use shared NO_SUSPEND interrupt lines for signaling system wakeup generally have to detect wakeup in their interrupt handlers. Thus if they happen to share an interrupt line with a NO_SUSPEND user, they also need to request that their interrupt handlers be run after suspend_device_irqs(). In both cases the reason for using IRQF_NO_SUSPEND is not because the driver in question has a genuine need to run its interrupt handler after suspend_device_irqs(), but because it happens to share the line with some other NO_SUSPEND user. Otherwise, the driver would do without IRQF_NO_SUSPEND just fine. To make it possible to specify that condition explicitly, introduce a new IRQ action handler flag for shared IRQs, IRQF_COND_SUSPEND, that, when set, will indicate to the IRQ core that the interrupt user is generally fine with suspending the IRQ, but it also can tolerate handler invocations after suspend_device_irqs() and, in particular, it is capable of detecting system wakeup and triggering it as appropriate from its interrupt handler. That will allow us to work around a problem with a shared timer interrupt line on at91 platforms. Link: http://marc.info/?l=linux-kernel&m=142252777602084&w=2 Link: http://marc.info/?t=142252775300011&r=1&w=2 Link: https://lkml.org/lkml/2014/12/15/552 Reported-by: Boris Brezillon Signed-off-by: Rafael J. Wysocki Acked-by: Peter Zijlstra (Intel) Acked-by: Mark Rutland --- include/linux/interrupt.h | 5 +++++ include/linux/irqdesc.h | 1 + kernel/irq/manage.c | 7 ++++++- kernel/irq/pm.c | 7 ++++++- 4 files changed, 18 insertions(+), 2 deletions(-) diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 606771c7cac2..2e88580194f0 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -59,6 +59,10 @@ * IRQF_NO_THREAD - Interrupt cannot be threaded * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device * resume time. + * IRQF_COND_SUSPEND - If the IRQ is shared with a NO_SUSPEND user, execute this + * interrupt handler after suspending interrupts. For system + * wakeup devices users need to implement wakeup detection in + * their interrupt handlers. */ #define IRQF_DISABLED 0x00000020 #define IRQF_SHARED 0x00000080 @@ -72,6 +76,7 @@ #define IRQF_FORCE_RESUME 0x00008000 #define IRQF_NO_THREAD 0x00010000 #define IRQF_EARLY_RESUME 0x00020000 +#define IRQF_COND_SUSPEND 0x00040000 #define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD) diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h index faf433af425e..dd1109fb241e 100644 --- a/include/linux/irqdesc.h +++ b/include/linux/irqdesc.h @@ -78,6 +78,7 @@ struct irq_desc { #ifdef CONFIG_PM_SLEEP unsigned int nr_actions; unsigned int no_suspend_depth; + unsigned int cond_suspend_depth; unsigned int force_resume_depth; #endif #ifdef CONFIG_PROC_FS diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 196a06fbc122..886d09e691d5 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1474,8 +1474,13 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler, * otherwise we'll have trouble later trying to figure out * which interrupt is which (messes up the interrupt freeing * logic etc). + * + * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and + * it cannot be set along with IRQF_NO_SUSPEND. */ - if ((irqflags & IRQF_SHARED) && !dev_id) + if (((irqflags & IRQF_SHARED) && !dev_id) || + (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) || + ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND))) return -EINVAL; desc = irq_to_desc(irq); diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c index 3ca532592704..5204a6d1b985 100644 --- a/kernel/irq/pm.c +++ b/kernel/irq/pm.c @@ -43,9 +43,12 @@ void irq_pm_install_action(struct irq_desc *desc, struct irqaction *action) if (action->flags & IRQF_NO_SUSPEND) desc->no_suspend_depth++; + else if (action->flags & IRQF_COND_SUSPEND) + desc->cond_suspend_depth++; WARN_ON_ONCE(desc->no_suspend_depth && - desc->no_suspend_depth != desc->nr_actions); + (desc->no_suspend_depth + + desc->cond_suspend_depth) != desc->nr_actions); } /* @@ -61,6 +64,8 @@ void irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action) if (action->flags & IRQF_NO_SUSPEND) desc->no_suspend_depth--; + else if (action->flags & IRQF_COND_SUSPEND) + desc->cond_suspend_depth--; } static bool suspend_device_irq(struct irq_desc *desc, int irq) -- cgit v1.2.3 From 432ec92b299e4bcbb0d9a116789563d53b2798e1 Mon Sep 17 00:00:00 2001 From: Boris BREZILLON Date: Mon, 2 Mar 2015 10:18:13 +0100 Subject: PM / wakeup: export pm_system_wakeup symbol Export pm_system_wakeup function to allow irq handlers to deal with system wakeup. This is needed for shared IRQ lines where one of the handler is registered with IRQF_NO_SUSPEND, while the other ones want to configure it as a wakeup source. In this specific case, irq core does not handle the wakeup process and leave the decision to each irq handler. Signed-off-by: Boris Brezillon Reviewed-by: Alexandre Belloni Acked-by: Nicolas Ferre Acked-by: Mark Rutland Signed-off-by: Rafael J. Wysocki --- drivers/base/power/wakeup.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c index c2744b30d5d9..aab7158d2afe 100644 --- a/drivers/base/power/wakeup.c +++ b/drivers/base/power/wakeup.c @@ -730,6 +730,7 @@ void pm_system_wakeup(void) pm_abort_suspend = true; freeze_wake(); } +EXPORT_SYMBOL_GPL(pm_system_wakeup); void pm_wakeup_clear(void) { -- cgit v1.2.3 From 603b1a232604dcd19a28eaddf70eee9fbe3edc88 Mon Sep 17 00:00:00 2001 From: Boris BREZILLON Date: Mon, 2 Mar 2015 10:18:14 +0100 Subject: rtc: at91sam9: rework wakeup and interrupt handling The IRQ line used by the RTC device is usually shared with the system timer (PIT) on at91 platforms. Since timers are registering their handlers with IRQF_NO_SUSPEND, we should expect being called in suspended state, and properly wake the system up when this is the case. Set IRQF_COND_SUSPEND flag when registering the IRQ handler to inform irq core that it can safely be called while the system is suspended. Signed-off-by: Boris Brezillon Reviewed-by: Alexandre Belloni Acked-by: Nicolas Ferre Acked-by: Mark Rutland Signed-off-by: Rafael J. Wysocki --- drivers/rtc/rtc-at91sam9.c | 73 ++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 61 insertions(+), 12 deletions(-) diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c index 2183fd2750ab..5ccaee32df72 100644 --- a/drivers/rtc/rtc-at91sam9.c +++ b/drivers/rtc/rtc-at91sam9.c @@ -23,6 +23,7 @@ #include #include #include +#include #include /* @@ -77,6 +78,9 @@ struct sam9_rtc { unsigned int gpbr_offset; int irq; struct clk *sclk; + bool suspended; + unsigned long events; + spinlock_t lock; }; #define rtt_readl(rtc, field) \ @@ -271,14 +275,9 @@ static int at91_rtc_proc(struct device *dev, struct seq_file *seq) return 0; } -/* - * IRQ handler for the RTC - */ -static irqreturn_t at91_rtc_interrupt(int irq, void *_rtc) +static irqreturn_t at91_rtc_cache_events(struct sam9_rtc *rtc) { - struct sam9_rtc *rtc = _rtc; u32 sr, mr; - unsigned long events = 0; /* Shared interrupt may be for another device. Note: reading * SR clears it, so we must only read it in this irq handler! @@ -290,18 +289,54 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *_rtc) /* alarm status */ if (sr & AT91_RTT_ALMS) - events |= (RTC_AF | RTC_IRQF); + rtc->events |= (RTC_AF | RTC_IRQF); /* timer update/increment */ if (sr & AT91_RTT_RTTINC) - events |= (RTC_UF | RTC_IRQF); + rtc->events |= (RTC_UF | RTC_IRQF); + + return IRQ_HANDLED; +} + +static void at91_rtc_flush_events(struct sam9_rtc *rtc) +{ + if (!rtc->events) + return; - rtc_update_irq(rtc->rtcdev, 1, events); + rtc_update_irq(rtc->rtcdev, 1, rtc->events); + rtc->events = 0; pr_debug("%s: num=%ld, events=0x%02lx\n", __func__, - events >> 8, events & 0x000000FF); + rtc->events >> 8, rtc->events & 0x000000FF); +} - return IRQ_HANDLED; +/* + * IRQ handler for the RTC + */ +static irqreturn_t at91_rtc_interrupt(int irq, void *_rtc) +{ + struct sam9_rtc *rtc = _rtc; + int ret; + + spin_lock(&rtc->lock); + + ret = at91_rtc_cache_events(rtc); + + /* We're called in suspended state */ + if (rtc->suspended) { + /* Mask irqs coming from this peripheral */ + rtt_writel(rtc, MR, + rtt_readl(rtc, MR) & + ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN)); + /* Trigger a system wakeup */ + pm_system_wakeup(); + } else { + at91_rtc_flush_events(rtc); + } + + spin_unlock(&rtc->lock); + + return ret; } static const struct rtc_class_ops at91_rtc_ops = { @@ -421,7 +456,8 @@ static int at91_rtc_probe(struct platform_device *pdev) /* register irq handler after we know what name we'll use */ ret = devm_request_irq(&pdev->dev, rtc->irq, at91_rtc_interrupt, - IRQF_SHARED, dev_name(&rtc->rtcdev->dev), rtc); + IRQF_SHARED | IRQF_COND_SUSPEND, + dev_name(&rtc->rtcdev->dev), rtc); if (ret) { dev_dbg(&pdev->dev, "can't share IRQ %d?\n", rtc->irq); return ret; @@ -482,7 +518,12 @@ static int at91_rtc_suspend(struct device *dev) rtc->imr = mr & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN); if (rtc->imr) { if (device_may_wakeup(dev) && (mr & AT91_RTT_ALMIEN)) { + unsigned long flags; + enable_irq_wake(rtc->irq); + spin_lock_irqsave(&rtc->lock, flags); + rtc->suspended = true; + spin_unlock_irqrestore(&rtc->lock, flags); /* don't let RTTINC cause wakeups */ if (mr & AT91_RTT_RTTINCIEN) rtt_writel(rtc, MR, mr & ~AT91_RTT_RTTINCIEN); @@ -499,10 +540,18 @@ static int at91_rtc_resume(struct device *dev) u32 mr; if (rtc->imr) { + unsigned long flags; + if (device_may_wakeup(dev)) disable_irq_wake(rtc->irq); mr = rtt_readl(rtc, MR); rtt_writel(rtc, MR, mr | rtc->imr); + + spin_lock_irqsave(&rtc->lock, flags); + rtc->suspended = false; + at91_rtc_cache_events(rtc); + at91_rtc_flush_events(rtc); + spin_unlock_irqrestore(&rtc->lock, flags); } return 0; -- cgit v1.2.3 From dd1f1f391dd7f3a39a3983df2ca076871111cec9 Mon Sep 17 00:00:00 2001 From: Boris BREZILLON Date: Mon, 2 Mar 2015 10:18:15 +0100 Subject: rtc: at91rm9200: rework wakeup and interrupt handling The IRQ line used by the RTC device is usually shared with the system timer (PIT) on at91 platforms. Since timers are registering their handlers with IRQF_NO_SUSPEND, we should expect being called in suspended state, and properly wake the system up when this is the case. Set IRQF_COND_SUSPEND flag when registering the IRQ handler to inform irq core that it can safely be called while the system is suspended. Signed-off-by: Boris Brezillon Reviewed-by: Alexandre Belloni Acked-by: Nicolas Ferre Acked-by: Mark Rutland Signed-off-by: Rafael J. Wysocki --- drivers/rtc/rtc-at91rm9200.c | 62 ++++++++++++++++++++++++++++++++++---------- 1 file changed, 48 insertions(+), 14 deletions(-) diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c index 70a5d94cc766..b4f7744f6751 100644 --- a/drivers/rtc/rtc-at91rm9200.c +++ b/drivers/rtc/rtc-at91rm9200.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include "rtc-at91rm9200.h" @@ -54,6 +55,10 @@ static void __iomem *at91_rtc_regs; static int irq; static DEFINE_SPINLOCK(at91_rtc_lock); static u32 at91_rtc_shadow_imr; +static bool suspended; +static DEFINE_SPINLOCK(suspended_lock); +static unsigned long cached_events; +static u32 at91_rtc_imr; static void at91_rtc_write_ier(u32 mask) { @@ -290,7 +295,9 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id) struct rtc_device *rtc = platform_get_drvdata(pdev); unsigned int rtsr; unsigned long events = 0; + int ret = IRQ_NONE; + spin_lock(&suspended_lock); rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr(); if (rtsr) { /* this interrupt is shared! Is it ours? */ if (rtsr & AT91_RTC_ALARM) @@ -304,14 +311,22 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id) at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */ - rtc_update_irq(rtc, 1, events); + if (!suspended) { + rtc_update_irq(rtc, 1, events); - dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__, - events >> 8, events & 0x000000FF); + dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", + __func__, events >> 8, events & 0x000000FF); + } else { + cached_events |= events; + at91_rtc_write_idr(at91_rtc_imr); + pm_system_wakeup(); + } - return IRQ_HANDLED; + ret = IRQ_HANDLED; } - return IRQ_NONE; /* not handled */ + spin_lock(&suspended_lock); + + return ret; } static const struct at91_rtc_config at91rm9200_config = { @@ -401,8 +416,8 @@ static int __init at91_rtc_probe(struct platform_device *pdev) AT91_RTC_CALEV); ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt, - IRQF_SHARED, - "at91_rtc", pdev); + IRQF_SHARED | IRQF_COND_SUSPEND, + "at91_rtc", pdev); if (ret) { dev_err(&pdev->dev, "IRQ %d already in use.\n", irq); return ret; @@ -454,8 +469,6 @@ static void at91_rtc_shutdown(struct platform_device *pdev) /* AT91RM9200 RTC Power management control */ -static u32 at91_rtc_imr; - static int at91_rtc_suspend(struct device *dev) { /* this IRQ is shared with DBGU and other hardware which isn't @@ -464,21 +477,42 @@ static int at91_rtc_suspend(struct device *dev) at91_rtc_imr = at91_rtc_read_imr() & (AT91_RTC_ALARM|AT91_RTC_SECEV); if (at91_rtc_imr) { - if (device_may_wakeup(dev)) + if (device_may_wakeup(dev)) { + unsigned long flags; + enable_irq_wake(irq); - else + + spin_lock_irqsave(&suspended_lock, flags); + suspended = true; + spin_unlock_irqrestore(&suspended_lock, flags); + } else { at91_rtc_write_idr(at91_rtc_imr); + } } return 0; } static int at91_rtc_resume(struct device *dev) { + struct rtc_device *rtc = dev_get_drvdata(dev); + if (at91_rtc_imr) { - if (device_may_wakeup(dev)) + if (device_may_wakeup(dev)) { + unsigned long flags; + + spin_lock_irqsave(&suspended_lock, flags); + + if (cached_events) { + rtc_update_irq(rtc, 1, cached_events); + cached_events = 0; + } + + suspended = false; + spin_unlock_irqrestore(&suspended_lock, flags); + disable_irq_wake(irq); - else - at91_rtc_write_ier(at91_rtc_imr); + } + at91_rtc_write_ier(at91_rtc_imr); } return 0; } -- cgit v1.2.3 From 947f5b108543a6521728466ad5be6e2c4a35a65b Mon Sep 17 00:00:00 2001 From: Boris BREZILLON Date: Mon, 2 Mar 2015 10:18:16 +0100 Subject: clk: at91: implement suspend/resume for the PMC irqchip The irq line used by the PMC block is shared with several peripherals including the init timer which is registering its handler with IRQF_NO_SUSPEND. Implement the appropriate suspend/resume callback for the PMC irqchip, and inform irq core that PMC irq handler can be safely called while the system is suspended by setting IRQF_COND_SUSPEND. Signed-off-by: Boris Brezillon Reviewed-by: Alexandre Belloni Acked-by: Nicolas Ferre Acked-by: Mark Rutland Signed-off-by: Rafael J. Wysocki --- drivers/clk/at91/pmc.c | 20 +++++++++++++++++++- drivers/clk/at91/pmc.h | 1 + 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c index f07c8152e5cc..3f27d21fb729 100644 --- a/drivers/clk/at91/pmc.c +++ b/drivers/clk/at91/pmc.c @@ -89,12 +89,29 @@ static int pmc_irq_set_type(struct irq_data *d, unsigned type) return 0; } +static void pmc_irq_suspend(struct irq_data *d) +{ + struct at91_pmc *pmc = irq_data_get_irq_chip_data(d); + + pmc->imr = pmc_read(pmc, AT91_PMC_IMR); + pmc_write(pmc, AT91_PMC_IDR, pmc->imr); +} + +static void pmc_irq_resume(struct irq_data *d) +{ + struct at91_pmc *pmc = irq_data_get_irq_chip_data(d); + + pmc_write(pmc, AT91_PMC_IER, pmc->imr); +} + static struct irq_chip pmc_irq = { .name = "PMC", .irq_disable = pmc_irq_mask, .irq_mask = pmc_irq_mask, .irq_unmask = pmc_irq_unmask, .irq_set_type = pmc_irq_set_type, + .irq_suspend = pmc_irq_suspend, + .irq_resume = pmc_irq_resume, }; static struct lock_class_key pmc_lock_class; @@ -224,7 +241,8 @@ static struct at91_pmc *__init at91_pmc_init(struct device_node *np, goto out_free_pmc; pmc_write(pmc, AT91_PMC_IDR, 0xffffffff); - if (request_irq(pmc->virq, pmc_irq_handler, IRQF_SHARED, "pmc", pmc)) + if (request_irq(pmc->virq, pmc_irq_handler, + IRQF_SHARED | IRQF_COND_SUSPEND, "pmc", pmc)) goto out_remove_irqdomain; return pmc; diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h index 52d2041fa3f6..69abb08cf146 100644 --- a/drivers/clk/at91/pmc.h +++ b/drivers/clk/at91/pmc.h @@ -33,6 +33,7 @@ struct at91_pmc { spinlock_t lock; const struct at91_pmc_caps *caps; struct irq_domain *irqdomain; + u32 imr; }; static inline void pmc_lock(struct at91_pmc *pmc) -- cgit v1.2.3 From d677772e1358924bf487cd833bdc4d50f3f6f64d Mon Sep 17 00:00:00 2001 From: Boris BREZILLON Date: Mon, 2 Mar 2015 10:18:17 +0100 Subject: watchdog: at91sam9: request the irq with IRQF_NO_SUSPEND The watchdog interrupt (only used when activating software watchdog) shouldn't be suspended when entering suspend mode, because it is shared with a timer device (which request the line with IRQF_NO_SUSPEND) and once the watchdog "Mode Register" has been written, it cannot be changed (which means we cannot disable the watchdog interrupt when entering suspend). Signed-off-by: Boris Brezillon Reviewed-by: Alexandre Belloni Acked-by: Guenter Roeck Acked-by: Nicolas Ferre Signed-off-by: Rafael J. Wysocki --- drivers/watchdog/at91sam9_wdt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/watchdog/at91sam9_wdt.c b/drivers/watchdog/at91sam9_wdt.c index 6df940528fd2..1443b3c391de 100644 --- a/drivers/watchdog/at91sam9_wdt.c +++ b/drivers/watchdog/at91sam9_wdt.c @@ -208,7 +208,8 @@ static int at91_wdt_init(struct platform_device *pdev, struct at91wdt *wdt) if ((tmp & AT91_WDT_WDFIEN) && wdt->irq) { err = request_irq(wdt->irq, wdt_interrupt, - IRQF_SHARED | IRQF_IRQPOLL, + IRQF_SHARED | IRQF_IRQPOLL | + IRQF_NO_SUSPEND, pdev->name, wdt); if (err) return err; -- cgit v1.2.3 From 2c7af5ba65cfb0145ad8e11f856035c10ba0d22c Mon Sep 17 00:00:00 2001 From: Boris BREZILLON Date: Mon, 2 Mar 2015 10:18:18 +0100 Subject: tty: serial: atmel: rework interrupt and wakeup handling The IRQ line connected to the DBGU UART is often shared with a timer device which request the IRQ with IRQF_NO_SUSPEND. Since the UART driver is correctly disabling IRQs when entering suspend we can safely request the IRQ with IRQF_COND_SUSPEND so that irq core will not complain about mixing IRQF_NO_SUSPEND and !IRQF_NO_SUSPEND. Rework the interrupt handler to wake the system up when an interrupt happens on the DEBUG_UART while the system is suspended. Signed-off-by: Boris Brezillon Reviewed-by: Alexandre Belloni Acked-by: Nicolas Ferre Acked-by: Mark Rutland Signed-off-by: Rafael J. Wysocki --- drivers/tty/serial/atmel_serial.c | 49 +++++++++++++++++++++++++++++++++++---- 1 file changed, 45 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 846552bff67d..4e959c43f680 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -47,6 +47,7 @@ #include #include #include +#include #include #include @@ -173,6 +174,12 @@ struct atmel_uart_port { bool ms_irq_enabled; bool is_usart; /* usart or uart */ struct timer_list uart_timer; /* uart timer */ + + bool suspended; + unsigned int pending; + unsigned int pending_status; + spinlock_t lock_suspended; + int (*prepare_rx)(struct uart_port *port); int (*prepare_tx)(struct uart_port *port); void (*schedule_rx)(struct uart_port *port); @@ -1179,12 +1186,15 @@ static irqreturn_t atmel_interrupt(int irq, void *dev_id) { struct uart_port *port = dev_id; struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); - unsigned int status, pending, pass_counter = 0; + unsigned int status, pending, mask, pass_counter = 0; bool gpio_handled = false; + spin_lock(&atmel_port->lock_suspended); + do { status = atmel_get_lines_status(port); - pending = status & UART_GET_IMR(port); + mask = UART_GET_IMR(port); + pending = status & mask; if (!gpio_handled) { /* * Dealing with GPIO interrupt @@ -1206,11 +1216,21 @@ static irqreturn_t atmel_interrupt(int irq, void *dev_id) if (!pending) break; + if (atmel_port->suspended) { + atmel_port->pending |= pending; + atmel_port->pending_status = status; + UART_PUT_IDR(port, mask); + pm_system_wakeup(); + break; + } + atmel_handle_receive(port, pending); atmel_handle_status(port, pending, status); atmel_handle_transmit(port, pending); } while (pass_counter++ < ATMEL_ISR_PASS_LIMIT); + spin_unlock(&atmel_port->lock_suspended); + return pass_counter ? IRQ_HANDLED : IRQ_NONE; } @@ -1742,7 +1762,8 @@ static int atmel_startup(struct uart_port *port) /* * Allocate the IRQ */ - retval = request_irq(port->irq, atmel_interrupt, IRQF_SHARED, + retval = request_irq(port->irq, atmel_interrupt, + IRQF_SHARED | IRQF_COND_SUSPEND, tty ? tty->name : "atmel_serial", port); if (retval) { dev_err(port->dev, "atmel_startup - Can't get irq\n"); @@ -2513,8 +2534,14 @@ static int atmel_serial_suspend(struct platform_device *pdev, /* we can not wake up if we're running on slow clock */ atmel_port->may_wakeup = device_may_wakeup(&pdev->dev); - if (atmel_serial_clk_will_stop()) + if (atmel_serial_clk_will_stop()) { + unsigned long flags; + + spin_lock_irqsave(&atmel_port->lock_suspended, flags); + atmel_port->suspended = true; + spin_unlock_irqrestore(&atmel_port->lock_suspended, flags); device_set_wakeup_enable(&pdev->dev, 0); + } uart_suspend_port(&atmel_uart, port); @@ -2525,6 +2552,18 @@ static int atmel_serial_resume(struct platform_device *pdev) { struct uart_port *port = platform_get_drvdata(pdev); struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); + unsigned long flags; + + spin_lock_irqsave(&atmel_port->lock_suspended, flags); + if (atmel_port->pending) { + atmel_handle_receive(port, atmel_port->pending); + atmel_handle_status(port, atmel_port->pending, + atmel_port->pending_status); + atmel_handle_transmit(port, atmel_port->pending); + atmel_port->pending = 0; + } + atmel_port->suspended = false; + spin_unlock_irqrestore(&atmel_port->lock_suspended, flags); uart_resume_port(&atmel_uart, port); device_set_wakeup_enable(&pdev->dev, atmel_port->may_wakeup); @@ -2593,6 +2632,8 @@ static int atmel_serial_probe(struct platform_device *pdev) port->backup_imr = 0; port->uart.line = ret; + spin_lock_init(&port->lock_suspended); + ret = atmel_init_gpios(port, &pdev->dev); if (ret < 0) dev_err(&pdev->dev, "%s", -- cgit v1.2.3 From 7438b633a6b073d66a3fa3678ec0dd5928caa4af Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 4 Mar 2015 20:00:40 +0000 Subject: genirq / PM: describe IRQF_COND_SUSPEND With certain restrictions it is possible for a wakeup device to share an IRQ with an IRQF_NO_SUSPEND user, and the warnings introduced by commit cab303be91dc47942bc25de33dc1140123540800 are spurious. The new IRQF_COND_SUSPEND flag allows drivers to tell the core when these restrictions are met, allowing spurious warnings to be silenced. This patch documents how IRQF_COND_SUSPEND is expected to be used, updating some of the text now made invalid by its addition. Signed-off-by: Mark Rutland Signed-off-by: Rafael J. Wysocki --- Documentation/power/suspend-and-interrupts.txt | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/Documentation/power/suspend-and-interrupts.txt b/Documentation/power/suspend-and-interrupts.txt index 50493c9284b4..8afb29a8604a 100644 --- a/Documentation/power/suspend-and-interrupts.txt +++ b/Documentation/power/suspend-and-interrupts.txt @@ -112,8 +112,9 @@ any special interrupt handling logic for it to work. IRQF_NO_SUSPEND and enable_irq_wake() ------------------------------------- -There are no valid reasons to use both enable_irq_wake() and the IRQF_NO_SUSPEND -flag on the same IRQ. +There are very few valid reasons to use both enable_irq_wake() and the +IRQF_NO_SUSPEND flag on the same IRQ, and it is never valid to use both for the +same device. First of all, if the IRQ is not shared, the rules for handling IRQF_NO_SUSPEND interrupts (interrupt handlers are invoked after suspend_device_irqs()) are @@ -122,4 +123,13 @@ handlers are not invoked after suspend_device_irqs()). Second, both enable_irq_wake() and IRQF_NO_SUSPEND apply to entire IRQs and not to individual interrupt handlers, so sharing an IRQ between a system wakeup -interrupt source and an IRQF_NO_SUSPEND interrupt source does not make sense. +interrupt source and an IRQF_NO_SUSPEND interrupt source does not generally +make sense. + +In rare cases an IRQ can be shared between a wakeup device driver and an +IRQF_NO_SUSPEND user. In order for this to be safe, the wakeup device driver +must be able to discern spurious IRQs from genuine wakeup events (signalling +the latter to the core with pm_system_wakeup()), must use enable_irq_wake() to +ensure that the IRQ will function as a wakeup source, and must request the IRQ +with IRQF_COND_SUSPEND to tell the core that it meets these requirements. If +these requirements are not met, it is not valid to use IRQF_COND_SUSPEND. -- cgit v1.2.3