Revert "drivers/rtc/rtc-at91rm9200.c: use a variable for storing IMR"

This reverts commit 0ef1594c017521ea89278e80fe3f80dafb17abde.

This patch introduced a few races which cannot be easily fixed with a
small follow-up patch. Furthermore, the SoC with the broken hardware
register, which this patch intended to add support for, can only be used
with device trees, which this driver currently does not support.

[ Here is the discussion that led to this "revert" patch:
  https://lkml.org/lkml/2013/4/3/176 ]

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
index 0a9f27e..434ebc3 100644 (file)
--- a/drivers/rtc/rtc-at91rm9200.c
+++ b/drivers/rtc/rtc-at91rm9200.c
@@ -44,7 +44,6 @@ 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
@@ -109,11 +108,9 @@ 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
@@ -145,7 +142,7 @@ 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_imr & AT91_RTC_ALARM)
+       alrm->enabled = (at91_rtc_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
                        ? 1 : 0;
 
        dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
@@ -171,7 +168,6 @@ 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
@@ -184,7 +180,6 @@ 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);
        }
 
@@ -201,12 +196,9 @@ 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;
 }
@@ -215,10 +207,12 @@ 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",
-                       (at91_rtc_imr & AT91_RTC_ACKUPD) ? "yes" : "no");
+                       (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
        seq_printf(seq, "periodic_IRQ\t: %s\n",
-                       (at91_rtc_imr & AT91_RTC_SECEV) ? "yes" : "no");
+                       (imr & AT91_RTC_SECEV) ? "yes" : "no");
 
        return 0;
 }
@@ -233,7 +227,7 @@ 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_imr;
+       rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read(AT91_RTC_IMR);
        if (rtsr) {             /* this interrupt is shared!  Is it ours? */
                if (rtsr & AT91_RTC_ALARM)
                        events |= (RTC_AF | RTC_IRQF);
@@ -297,7 +291,6 @@ 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,
@@ -336,7 +329,6 @@ 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);
@@ -349,35 +341,31 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
 
 /* AT91RM9200 RTC Power management control */
 
-static u32 at91_rtc_bkpimr;
-
+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
         * necessarily doing PM like we are...
         */
-       at91_rtc_bkpimr = at91_rtc_imr & (AT91_RTC_ALARM|AT91_RTC_SECEV);
-       if (at91_rtc_bkpimr) {
-               if (device_may_wakeup(dev)) {
+       at91_rtc_imr = at91_rtc_read(AT91_RTC_IMR)
+                       & (AT91_RTC_ALARM|AT91_RTC_SECEV);
+       if (at91_rtc_imr) {
+               if (device_may_wakeup(dev))
                        enable_irq_wake(irq);
-               } else {
-                       at91_rtc_write(AT91_RTC_IDR, at91_rtc_bkpimr);
-                       at91_rtc_imr &= ~at91_rtc_bkpimr;
-               }
-}
+               else
+                       at91_rtc_write(AT91_RTC_IDR, at91_rtc_imr);
+       }
        return 0;
 }
 
 static int at91_rtc_resume(struct device *dev)
 {
-       if (at91_rtc_bkpimr) {
-               if (device_may_wakeup(dev)) {
+       if (at91_rtc_imr) {
+               if (device_may_wakeup(dev))
                        disable_irq_wake(irq);
-               } else {
-                       at91_rtc_imr |= at91_rtc_bkpimr;
-                       at91_rtc_write(AT91_RTC_IER, at91_rtc_bkpimr);
-               }
+               else
+                       at91_rtc_write(AT91_RTC_IER, at91_rtc_imr);
        }
        return 0;
 }

diff --git a/drivers/rtc/rtc-at91rm9200.h b/drivers/rtc/rtc-at91rm9200.h
index 5f940b6..da1945e 100644 (file)
--- a/drivers/rtc/rtc-at91rm9200.h
+++ b/drivers/rtc/rtc-at91rm9200.h
@@ -64,6 +64,7 @@
 #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 */