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@atmel.com> Reported-by: Douglas Gilbert <dgilbert@interlog.com> Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Cc: Ludovic Desroches <ludovic.desroches@atmel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>wifi-calibration
Nicolas Ferre
Linus Torvalds
parent
e66b05873a
commit
0ef1594c01
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@ -44,6 +44,7 @@ static DECLARE_COMPLETION(at91_rtc_updated);
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static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
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static void __iomem *at91_rtc_regs;
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static int irq;
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static u32 at91_rtc_imr;
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/*
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* Decode time/date into rtc_time structure
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@ -108,9 +109,11 @@ static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
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cr = at91_rtc_read(AT91_RTC_CR);
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at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
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at91_rtc_imr |= AT91_RTC_ACKUPD;
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at91_rtc_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
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wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
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at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
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at91_rtc_imr &= ~AT91_RTC_ACKUPD;
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at91_rtc_write(AT91_RTC_TIMR,
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bin2bcd(tm->tm_sec) << 0
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@ -142,7 +145,7 @@ static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
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tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
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tm->tm_year = at91_alarm_year - 1900;
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alrm->enabled = (at91_rtc_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
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alrm->enabled = (at91_rtc_imr & AT91_RTC_ALARM)
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? 1 : 0;
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dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
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@ -168,6 +171,7 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
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tm.tm_sec = alrm->time.tm_sec;
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at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
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at91_rtc_imr &= ~AT91_RTC_ALARM;
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at91_rtc_write(AT91_RTC_TIMALR,
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bin2bcd(tm.tm_sec) << 0
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| bin2bcd(tm.tm_min) << 8
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@ -180,6 +184,7 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
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if (alrm->enabled) {
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at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
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at91_rtc_imr |= AT91_RTC_ALARM;
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at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
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}
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@ -196,9 +201,12 @@ static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
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if (enabled) {
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at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
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at91_rtc_imr |= AT91_RTC_ALARM;
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at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
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} else
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} else {
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at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
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at91_rtc_imr &= ~AT91_RTC_ALARM;
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}
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return 0;
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}
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@ -207,12 +215,10 @@ static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
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*/
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static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
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{
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unsigned long imr = at91_rtc_read(AT91_RTC_IMR);
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seq_printf(seq, "update_IRQ\t: %s\n",
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(imr & AT91_RTC_ACKUPD) ? "yes" : "no");
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(at91_rtc_imr & AT91_RTC_ACKUPD) ? "yes" : "no");
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seq_printf(seq, "periodic_IRQ\t: %s\n",
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(imr & AT91_RTC_SECEV) ? "yes" : "no");
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(at91_rtc_imr & AT91_RTC_SECEV) ? "yes" : "no");
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return 0;
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}
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@ -227,7 +233,7 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
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unsigned int rtsr;
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unsigned long events = 0;
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rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read(AT91_RTC_IMR);
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rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_imr;
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if (rtsr) { /* this interrupt is shared! Is it ours? */
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if (rtsr & AT91_RTC_ALARM)
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events |= (RTC_AF | RTC_IRQF);
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@ -291,6 +297,7 @@ static int __init at91_rtc_probe(struct platform_device *pdev)
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at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
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AT91_RTC_SECEV | AT91_RTC_TIMEV |
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AT91_RTC_CALEV);
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at91_rtc_imr = 0;
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ret = request_irq(irq, at91_rtc_interrupt,
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IRQF_SHARED,
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@ -329,6 +336,7 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
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at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
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AT91_RTC_SECEV | AT91_RTC_TIMEV |
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AT91_RTC_CALEV);
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at91_rtc_imr = 0;
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free_irq(irq, pdev);
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rtc_device_unregister(rtc);
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@ -341,31 +349,35 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
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/* AT91RM9200 RTC Power management control */
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static u32 at91_rtc_imr;
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static u32 at91_rtc_bkpimr;
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static int at91_rtc_suspend(struct device *dev)
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{
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/* this IRQ is shared with DBGU and other hardware which isn't
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* necessarily doing PM like we are...
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*/
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at91_rtc_imr = at91_rtc_read(AT91_RTC_IMR)
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& (AT91_RTC_ALARM|AT91_RTC_SECEV);
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if (at91_rtc_imr) {
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if (device_may_wakeup(dev))
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at91_rtc_bkpimr = at91_rtc_imr & (AT91_RTC_ALARM|AT91_RTC_SECEV);
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if (at91_rtc_bkpimr) {
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if (device_may_wakeup(dev)) {
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enable_irq_wake(irq);
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else
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at91_rtc_write(AT91_RTC_IDR, at91_rtc_imr);
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}
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} else {
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at91_rtc_write(AT91_RTC_IDR, at91_rtc_bkpimr);
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at91_rtc_imr &= ~at91_rtc_bkpimr;
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}
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}
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return 0;
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}
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static int at91_rtc_resume(struct device *dev)
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{
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if (at91_rtc_imr) {
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if (device_may_wakeup(dev))
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if (at91_rtc_bkpimr) {
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if (device_may_wakeup(dev)) {
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disable_irq_wake(irq);
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else
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at91_rtc_write(AT91_RTC_IER, at91_rtc_imr);
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} else {
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at91_rtc_imr |= at91_rtc_bkpimr;
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at91_rtc_write(AT91_RTC_IER, at91_rtc_bkpimr);
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}
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}
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return 0;
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}
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@ -64,7 +64,6 @@
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#define AT91_RTC_SCCR 0x1c /* Status Clear Command Register */
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#define AT91_RTC_IER 0x20 /* Interrupt Enable Register */
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#define AT91_RTC_IDR 0x24 /* Interrupt Disable Register */
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#define AT91_RTC_IMR 0x28 /* Interrupt Mask Register */
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#define AT91_RTC_VER 0x2c /* Valid Entry Register */
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#define AT91_RTC_NVTIM (1 << 0) /* Non valid Time */
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