commit: 0ef1594c017521ea89278e80fe3f80dafb17abde From: Nicolas Ferre <nicolas.ferre@xxxxxxxxx> Date: Fri, 22 Mar 2013 15:04:47 -0700 Subject: drivers/rtc/rtc-at91rm9200.c: use a variable for storing IMR On some revisions of AT91 SoCs, the RTC IMR register is not working. Instead of elaborating a workaround for that specific SoC or IP version, we simply use a software variable to store the Interrupt Mask Register and modify it for each enabling/disabling of an interrupt. The overhead of this is negligible anyway. The interrupt mask register (IMR) for the RTC is broken on the AT91SAM9x5 sub-family of SoCs (good overview of the members here: http://www.eewiki.net/display/linuxonarm/AT91SAM9x5 ). The "user visible effect" is the RTC doesn't work. That sub-family is less than two years old and only has devicetree (DT) support and came online circa lk 3.7 . The dust is yet to settle on the DT stuff at least for AT91 SoCs (translation: lots of stuff is still broken, so much that it is hard to know where to start). The fix in the patch is pretty simple: just shadow the silicon IMR register with a variable in the driver. Some older SoCs (pre-DT) use the the rtc-at91rm9200 driver (e.g. obviously the AT91RM9200) and they should not be impacted by the change. There shouldn't be a large volume of interrupts associated with a RTC. Signed-off-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx> Reported-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx> Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@xxxxxxxxxxxx> Cc: Ludovic Desroches <ludovic.desroches@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> --- drivers/rtc/rtc-at91rm9200.c | 50 ++++++++++++++++++++++++++---------------- drivers/rtc/rtc-at91rm9200.h | 1 - 2 files changed, 31 insertions(+), 20 deletions(-) diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c index 434ebc3..0a9f27e 100644 --- a/drivers/rtc/rtc-at91rm9200.c +++ b/drivers/rtc/rtc-at91rm9200.c @@ -44,6 +44,7 @@ static DECLARE_COMPLETION(at91_rtc_updated); static unsigned int at91_alarm_year = AT91_RTC_EPOCH; static void __iomem *at91_rtc_regs; static int irq; +static u32 at91_rtc_imr; /* * Decode time/date into rtc_time structure @@ -108,9 +109,11 @@ static int at91_rtc_settime(struct device *dev, struct rtc_time *tm) cr = at91_rtc_read(AT91_RTC_CR); at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM); + at91_rtc_imr |= AT91_RTC_ACKUPD; at91_rtc_write(AT91_RTC_IER, AT91_RTC_ACKUPD); wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */ at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD); + at91_rtc_imr &= ~AT91_RTC_ACKUPD; at91_rtc_write(AT91_RTC_TIMR, bin2bcd(tm->tm_sec) << 0 @@ -142,7 +145,7 @@ static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); tm->tm_year = at91_alarm_year - 1900; - alrm->enabled = (at91_rtc_read(AT91_RTC_IMR) & AT91_RTC_ALARM) + alrm->enabled = (at91_rtc_imr & AT91_RTC_ALARM) ? 1 : 0; dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, @@ -168,6 +171,7 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) tm.tm_sec = alrm->time.tm_sec; at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM); + at91_rtc_imr &= ~AT91_RTC_ALARM; at91_rtc_write(AT91_RTC_TIMALR, bin2bcd(tm.tm_sec) << 0 | bin2bcd(tm.tm_min) << 8 @@ -180,6 +184,7 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) if (alrm->enabled) { at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); + at91_rtc_imr |= AT91_RTC_ALARM; at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM); } @@ -196,9 +201,12 @@ static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) if (enabled) { at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); + at91_rtc_imr |= AT91_RTC_ALARM; at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM); - } else + } else { at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM); + at91_rtc_imr &= ~AT91_RTC_ALARM; + } return 0; } @@ -207,12 +215,10 @@ static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) */ static int at91_rtc_proc(struct device *dev, struct seq_file *seq) { - unsigned long imr = at91_rtc_read(AT91_RTC_IMR); - seq_printf(seq, "update_IRQ\t: %s\n", - (imr & AT91_RTC_ACKUPD) ? "yes" : "no"); + (at91_rtc_imr & AT91_RTC_ACKUPD) ? "yes" : "no"); seq_printf(seq, "periodic_IRQ\t: %s\n", - (imr & AT91_RTC_SECEV) ? "yes" : "no"); + (at91_rtc_imr & AT91_RTC_SECEV) ? "yes" : "no"); return 0; } @@ -227,7 +233,7 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id) unsigned int rtsr; unsigned long events = 0; - rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read(AT91_RTC_IMR); + rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_imr; if (rtsr) { /* this interrupt is shared! Is it ours? */ if (rtsr & AT91_RTC_ALARM) events |= (RTC_AF | RTC_IRQF); @@ -291,6 +297,7 @@ static int __init at91_rtc_probe(struct platform_device *pdev) at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM | AT91_RTC_SECEV | AT91_RTC_TIMEV | AT91_RTC_CALEV); + at91_rtc_imr = 0; ret = request_irq(irq, at91_rtc_interrupt, IRQF_SHARED, @@ -329,6 +336,7 @@ static int __exit at91_rtc_remove(struct platform_device *pdev) at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM | AT91_RTC_SECEV | AT91_RTC_TIMEV | AT91_RTC_CALEV); + at91_rtc_imr = 0; free_irq(irq, pdev); rtc_device_unregister(rtc); @@ -341,31 +349,35 @@ static int __exit at91_rtc_remove(struct platform_device *pdev) /* AT91RM9200 RTC Power management control */ -static u32 at91_rtc_imr; +static u32 at91_rtc_bkpimr; + static int at91_rtc_suspend(struct device *dev) { /* this IRQ is shared with DBGU and other hardware which isn't * necessarily doing PM like we are... */ - at91_rtc_imr = at91_rtc_read(AT91_RTC_IMR) - & (AT91_RTC_ALARM|AT91_RTC_SECEV); - if (at91_rtc_imr) { - if (device_may_wakeup(dev)) + at91_rtc_bkpimr = at91_rtc_imr & (AT91_RTC_ALARM|AT91_RTC_SECEV); + if (at91_rtc_bkpimr) { + if (device_may_wakeup(dev)) { enable_irq_wake(irq); - else - at91_rtc_write(AT91_RTC_IDR, at91_rtc_imr); - } + } else { + at91_rtc_write(AT91_RTC_IDR, at91_rtc_bkpimr); + at91_rtc_imr &= ~at91_rtc_bkpimr; + } +} return 0; } static int at91_rtc_resume(struct device *dev) { - if (at91_rtc_imr) { - if (device_may_wakeup(dev)) + if (at91_rtc_bkpimr) { + if (device_may_wakeup(dev)) { disable_irq_wake(irq); - else - at91_rtc_write(AT91_RTC_IER, at91_rtc_imr); + } else { + at91_rtc_imr |= at91_rtc_bkpimr; + at91_rtc_write(AT91_RTC_IER, at91_rtc_bkpimr); + } } return 0; } diff --git a/drivers/rtc/rtc-at91rm9200.h b/drivers/rtc/rtc-at91rm9200.h index da1945e..5f940b6 100644 --- a/drivers/rtc/rtc-at91rm9200.h +++ b/drivers/rtc/rtc-at91rm9200.h @@ -64,7 +64,6 @@ #define AT91_RTC_SCCR 0x1c /* Status Clear Command Register */ #define AT91_RTC_IER 0x20 /* Interrupt Enable Register */ #define AT91_RTC_IDR 0x24 /* Interrupt Disable Register */ -#define AT91_RTC_IMR 0x28 /* Interrupt Mask Register */ #define AT91_RTC_VER 0x2c /* Valid Entry Register */ #define AT91_RTC_NVTIM (1 << 0) /* Non valid Time */ -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html