From bcd9b89c02295b075fda4bdb666f6641f8212226 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Sun, 1 Apr 2007 23:49:47 -0700 Subject: [PATCH] [PATCH] rtc-cmos lockdep fix, irq updates Lockdep reported cmos_suspend() and cmos_resume() calling rtc_update_irq() with IRQs enabled; not allowed. Also fix problems seen on some hardware, whereby false alarm IRQs could be reported (primarily to userspace); and update two comments to match changes in ACPI. Those make up most of this patch, by volume. Signed-off-by: David Brownell Cc: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rtc/rtc-cmos.c | 50 ++++++++++++++++++++++++++++-------------- 1 file changed, 33 insertions(+), 17 deletions(-) diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index 85bf795abdcc..7c0d60910077 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -59,6 +59,19 @@ struct cmos_rtc { static const char driver_name[] = "rtc_cmos"; +/* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear; + * always mask it against the irq enable bits in RTC_CONTROL. Bit values + * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both. + */ +#define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF) + +static inline int is_intr(u8 rtc_intr) +{ + if (!(rtc_intr & RTC_IRQF)) + return 0; + return rtc_intr & RTC_IRQMASK; +} + /*----------------------------------------------------------------*/ static int cmos_read_time(struct device *dev, struct rtc_time *t) @@ -188,7 +201,8 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t) rtc_control &= ~RTC_AIE; CMOS_WRITE(rtc_control, RTC_CONTROL); rtc_intr = CMOS_READ(RTC_INTR_FLAGS); - if (rtc_intr) + rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF; + if (is_intr(rtc_intr)) rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr); /* update alarm */ @@ -207,7 +221,8 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t) rtc_control |= RTC_AIE; CMOS_WRITE(rtc_control, RTC_CONTROL); rtc_intr = CMOS_READ(RTC_INTR_FLAGS); - if (rtc_intr) + rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF; + if (is_intr(rtc_intr)) rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr); } @@ -287,7 +302,8 @@ cmos_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) } CMOS_WRITE(rtc_control, RTC_CONTROL); rtc_intr = CMOS_READ(RTC_INTR_FLAGS); - if (rtc_intr) + rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF; + if (is_intr(rtc_intr)) rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr); spin_unlock_irqrestore(&rtc_lock, flags); return 0; @@ -353,12 +369,10 @@ static irqreturn_t cmos_interrupt(int irq, void *p) spin_lock(&rtc_lock); irqstat = CMOS_READ(RTC_INTR_FLAGS); + irqstat &= (CMOS_READ(RTC_CONTROL) & RTC_IRQMASK) | RTC_IRQF; spin_unlock(&rtc_lock); - if (irqstat) { - /* NOTE: irqstat may have e.g. RTC_PF set - * even when RTC_PIE is clear... - */ + if (is_intr(irqstat)) { rtc_update_irq(p, 1, irqstat); return IRQ_HANDLED; } else @@ -525,25 +539,26 @@ static int cmos_suspend(struct device *dev, pm_message_t mesg) { struct cmos_rtc *cmos = dev_get_drvdata(dev); int do_wake = device_may_wakeup(dev); - unsigned char tmp, irqstat; + unsigned char tmp; /* only the alarm might be a wakeup event source */ spin_lock_irq(&rtc_lock); cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL); if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) { + unsigned char irqstat; + if (do_wake) tmp &= ~(RTC_PIE|RTC_UIE); else tmp &= ~(RTC_PIE|RTC_AIE|RTC_UIE); CMOS_WRITE(tmp, RTC_CONTROL); irqstat = CMOS_READ(RTC_INTR_FLAGS); - } else - irqstat = 0; + irqstat &= (tmp & RTC_IRQMASK) | RTC_IRQF; + if (is_intr(irqstat)) + rtc_update_irq(&cmos->rtc->class_dev, 1, irqstat); + } spin_unlock_irq(&rtc_lock); - if (irqstat) - rtc_update_irq(&cmos->rtc->class_dev, 1, irqstat); - /* ACPI HOOK: enable ACPI_EVENT_RTC when (tmp & RTC_AIE) * ... it'd be best if we could do that under rtc_lock. */ @@ -573,9 +588,10 @@ static int cmos_resume(struct device *dev) spin_lock_irq(&rtc_lock); CMOS_WRITE(tmp, RTC_CONTROL); tmp = CMOS_READ(RTC_INTR_FLAGS); - spin_unlock_irq(&rtc_lock); - if (tmp) + tmp &= (cmos->suspend_ctrl & RTC_IRQMASK) | RTC_IRQF; + if (is_intr(tmp)) rtc_update_irq(&cmos->rtc->class_dev, 1, tmp); + spin_unlock_irq(&rtc_lock); } pr_debug("%s: resume, ctrl %02x\n", @@ -594,7 +610,7 @@ static int cmos_resume(struct device *dev) /*----------------------------------------------------------------*/ /* The "CMOS" RTC normally lives on the platform_bus. On ACPI systems, - * the device node may alternatively be created as a PNP device. + * the device node will always be created as a PNPACPI device. */ #ifdef CONFIG_PNPACPI @@ -673,7 +689,7 @@ module_exit(cmos_exit); /*----------------------------------------------------------------*/ /* Platform setup should have set up an RTC device, when PNPACPI is - * unavailable ... this is the normal case, common even on PCs. + * unavailable ... this could happen even on (older) PCs. */ static int __init cmos_platform_probe(struct platform_device *pdev)