forked from luck/tmp_suning_uos_patched
rtc-at91rm9200: avoid spurious irqs
This fixes kernel http://bugzilla.kernel.org/show_bug.cgi?id=11112 (bogus RTC update IRQs reported) for rtc-at91rm9200 by scrubbing old IRQ status before enabling IRQs. It also removes nonfunctional periodic IRQ support from this driver; only update IRQs are reported, or provided by the hardware. I suspect some other RTCs probably have versions of #11112; it's easy to overlook, since most non-RTC drivers don't care about spurious IRQs: they're not reported to userspace. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Report-by: W Unruh <unruh@physics.ubc.ca> Cc: Andrew Victor <avictor.za@gmail.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -171,8 +171,10 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
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| BIN2BCD(tm.tm_mday) << 24
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| AT91_RTC_DATEEN | AT91_RTC_MTHEN);
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if (alrm->enabled)
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if (alrm->enabled) {
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at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
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at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
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}
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pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
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at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
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@ -191,28 +193,22 @@ static int at91_rtc_ioctl(struct device *dev, unsigned int cmd,
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pr_debug("%s(): cmd=%08x, arg=%08lx.\n", __func__, cmd, arg);
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/* important: scrub old status before enabling IRQs */
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switch (cmd) {
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case RTC_AIE_OFF: /* alarm off */
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at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
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break;
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case RTC_AIE_ON: /* alarm on */
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at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
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at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
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break;
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case RTC_UIE_OFF: /* update off */
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case RTC_PIE_OFF: /* periodic off */
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at91_sys_write(AT91_RTC_IDR, AT91_RTC_SECEV);
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break;
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case RTC_UIE_ON: /* update on */
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case RTC_PIE_ON: /* periodic on */
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at91_sys_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
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at91_sys_write(AT91_RTC_IER, AT91_RTC_SECEV);
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break;
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case RTC_IRQP_READ: /* read periodic alarm frequency */
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ret = put_user(AT91_RTC_FREQ, (unsigned long *) arg);
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break;
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case RTC_IRQP_SET: /* set periodic alarm frequency */
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if (arg != AT91_RTC_FREQ)
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ret = -EINVAL;
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break;
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default:
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ret = -ENOIOCTLCMD;
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break;
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