1 files changed, 176 insertions, 118 deletions

diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index d7bb9bac71df..6ea349aba3ba 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -36,25 +36,9 @@
 #include <linux/platform_device.h>
 #include <linux/mod_devicetable.h>
 
-#ifdef CONFIG_HPET_EMULATE_RTC
-#include <asm/hpet.h>
-#endif
-
 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
 #include <asm-generic/rtc.h>
 
-#ifndef CONFIG_HPET_EMULATE_RTC
-#define is_hpet_enabled()                       0
-#define hpet_set_alarm_time(hrs, min, sec)      do { } while (0)
-#define hpet_set_periodic_freq(arg)             0
-#define hpet_mask_rtc_irq_bit(arg)              do { } while (0)
-#define hpet_set_rtc_irq_bit(arg)               do { } while (0)
-#define hpet_rtc_timer_init()                   do { } while (0)
-#define hpet_register_irq_handler(h)            0
-#define hpet_unregister_irq_handler(h)          do { } while (0)
-extern irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id);
-#endif
-
 struct cmos_rtc {
         struct rtc_device       *rtc;
         struct device           *dev;
@@ -93,6 +77,72 @@ static inline int is_intr(u8 rtc_intr)
 
 /*----------------------------------------------------------------*/
 
+/* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
+ * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
+ * used in a broken "legacy replacement" mode.  The breakage includes
+ * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
+ * other (better) use.
+ *
+ * When that broken mode is in use, platform glue provides a partial
+ * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
+ * want to use HPET for anything except those IRQs though...
+ */
+#ifdef CONFIG_HPET_EMULATE_RTC
+#include <asm/hpet.h>
+#else
+
+static inline int is_hpet_enabled(void)
+{
+        return 0;
+}
+
+static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
+{
+        return 0;
+}
+
+static inline int hpet_set_rtc_irq_bit(unsigned long mask)
+{
+        return 0;
+}
+
+static inline int
+hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
+{
+        return 0;
+}
+
+static inline int hpet_set_periodic_freq(unsigned long freq)
+{
+        return 0;
+}
+
+static inline int hpet_rtc_dropped_irq(void)
+{
+        return 0;
+}
+
+static inline int hpet_rtc_timer_init(void)
+{
+        return 0;
+}
+
+extern irq_handler_t hpet_rtc_interrupt;
+
+static inline int hpet_register_irq_handler(irq_handler_t handler)
+{
+        return 0;
+}
+
+static inline int hpet_unregister_irq_handler(irq_handler_t handler)
+{
+        return 0;
+}
+
+#endif
+
+/*----------------------------------------------------------------*/
+
 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 {
         /* REVISIT:  if the clock has a "century" register, use
@@ -185,11 +235,56 @@ static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
         return 0;
 }
 
+static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
+{
+        unsigned char   rtc_intr;
+
+        /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
+         * allegedly some older rtcs need that to handle irqs properly
+         */
+        rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
+
+        if (is_hpet_enabled())
+                return;
+
+        rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
+        if (is_intr(rtc_intr))
+                rtc_update_irq(cmos->rtc, 1, rtc_intr);
+}
+
+static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
+{
+        unsigned char   rtc_control;
+
+        /* flush any pending IRQ status, notably for update irqs,
+         * before we enable new IRQs
+         */
+        rtc_control = CMOS_READ(RTC_CONTROL);
+        cmos_checkintr(cmos, rtc_control);
+
+        rtc_control |= mask;
+        CMOS_WRITE(rtc_control, RTC_CONTROL);
+        hpet_set_rtc_irq_bit(mask);
+
+        cmos_checkintr(cmos, rtc_control);
+}
+
+static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
+{
+        unsigned char   rtc_control;
+
+        rtc_control = CMOS_READ(RTC_CONTROL);
+        rtc_control &= ~mask;
+        CMOS_WRITE(rtc_control, RTC_CONTROL);
+        hpet_mask_rtc_irq_bit(mask);
+
+        cmos_checkintr(cmos, rtc_control);
+}
+
 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 {
         struct cmos_rtc *cmos = dev_get_drvdata(dev);
         unsigned char   mon, mday, hrs, min, sec;
-        unsigned char   rtc_control, rtc_intr;
 
         if (!is_valid_irq(cmos->irq))
                 return -EIO;
@@ -213,17 +308,10 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
         sec = t->time.tm_sec;
         sec = (sec < 60) ? BIN2BCD(sec) : 0xff;
 
-        hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
         spin_lock_irq(&rtc_lock);
 
         /* next rtc irq must not be from previous alarm setting */
-        rtc_control = CMOS_READ(RTC_CONTROL);
-        rtc_control &= ~RTC_AIE;
-        CMOS_WRITE(rtc_control, RTC_CONTROL);
-        rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
-        rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
-        if (is_intr(rtc_intr))
-                rtc_update_irq(cmos->rtc, 1, rtc_intr);
+        cmos_irq_disable(cmos, RTC_AIE);
 
         /* update alarm */
         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
@@ -237,14 +325,13 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
                         CMOS_WRITE(mon, cmos->mon_alrm);
         }
 
-        if (t->enabled) {
-                rtc_control |= RTC_AIE;
-                CMOS_WRITE(rtc_control, RTC_CONTROL);
-                rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
-                rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
-                if (is_intr(rtc_intr))
-                        rtc_update_irq(cmos->rtc, 1, rtc_intr);
-        }
+        /* FIXME the HPET alarm glue currently ignores day_alrm
+         * and mon_alrm ...
+         */
+        hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
+
+        if (t->enabled)
+                cmos_irq_enable(cmos, RTC_AIE);
 
         spin_unlock_irq(&rtc_lock);
 
@@ -267,8 +354,8 @@ static int cmos_irq_set_freq(struct device *dev, int freq)
         f = 16 - f;
 
         spin_lock_irqsave(&rtc_lock, flags);
-        if (!hpet_set_periodic_freq(freq))
-                CMOS_WRITE(RTC_REF_CLCK_32KHZ | f, RTC_FREQ_SELECT);
+        hpet_set_periodic_freq(freq);
+        CMOS_WRITE(RTC_REF_CLCK_32KHZ | f, RTC_FREQ_SELECT);
         spin_unlock_irqrestore(&rtc_lock, flags);
 
         return 0;
@@ -277,26 +364,17 @@ static int cmos_irq_set_freq(struct device *dev, int freq)
 static int cmos_irq_set_state(struct device *dev, int enabled)
 {
         struct cmos_rtc *cmos = dev_get_drvdata(dev);
-        unsigned char   rtc_control, rtc_intr;
         unsigned long   flags;
 
         if (!is_valid_irq(cmos->irq))
                 return -ENXIO;
 
         spin_lock_irqsave(&rtc_lock, flags);
-        rtc_control = CMOS_READ(RTC_CONTROL);
 
         if (enabled)
-                rtc_control |= RTC_PIE;
+                cmos_irq_enable(cmos, RTC_PIE);
         else
-                rtc_control &= ~RTC_PIE;
-
-        CMOS_WRITE(rtc_control, RTC_CONTROL);
-
-        rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
-        rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
-        if (is_intr(rtc_intr))
-                rtc_update_irq(cmos->rtc, 1, rtc_intr);
+                cmos_irq_disable(cmos, RTC_PIE);
 
         spin_unlock_irqrestore(&rtc_lock, flags);
         return 0;
@@ -308,7 +386,6 @@ static int
 cmos_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
         struct cmos_rtc *cmos = dev_get_drvdata(dev);
-        unsigned char   rtc_control, rtc_intr;
         unsigned long   flags;
 
         switch (cmd) {
@@ -316,51 +393,29 @@ cmos_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
         case RTC_AIE_ON:
         case RTC_UIE_OFF:
         case RTC_UIE_ON:
-        case RTC_PIE_OFF:
-        case RTC_PIE_ON:
                 if (!is_valid_irq(cmos->irq))
                         return -EINVAL;
                 break;
+        /* PIE ON/OFF is handled by cmos_irq_set_state() */
         default:
                 return -ENOIOCTLCMD;
         }
 
         spin_lock_irqsave(&rtc_lock, flags);
-        rtc_control = CMOS_READ(RTC_CONTROL);
         switch (cmd) {
         case RTC_AIE_OFF:       /* alarm off */
-                rtc_control &= ~RTC_AIE;
-                hpet_mask_rtc_irq_bit(RTC_AIE);
+                cmos_irq_disable(cmos, RTC_AIE);
                 break;
         case RTC_AIE_ON:        /* alarm on */
-                rtc_control |= RTC_AIE;
-                hpet_set_rtc_irq_bit(RTC_AIE);
+                cmos_irq_enable(cmos, RTC_AIE);
                 break;
         case RTC_UIE_OFF:       /* update off */
-                rtc_control &= ~RTC_UIE;
-                hpet_mask_rtc_irq_bit(RTC_UIE);
+                cmos_irq_disable(cmos, RTC_UIE);
                 break;
         case RTC_UIE_ON:        /* update on */
-                rtc_control |= RTC_UIE;
-                hpet_set_rtc_irq_bit(RTC_UIE);
-                break;
-        case RTC_PIE_OFF:       /* periodic off */
-                rtc_control &= ~RTC_PIE;
-                hpet_mask_rtc_irq_bit(RTC_PIE);
-                break;
-        case RTC_PIE_ON:        /* periodic on */
-                rtc_control |= RTC_PIE;
-                hpet_set_rtc_irq_bit(RTC_PIE);
+                cmos_irq_enable(cmos, RTC_UIE);
                 break;
         }
-        if (!is_hpet_enabled())
-                CMOS_WRITE(rtc_control, RTC_CONTROL);
-
-        rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
-        rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
-        if (is_intr(rtc_intr))
-                rtc_update_irq(cmos->rtc, 1, rtc_intr);
-
         spin_unlock_irqrestore(&rtc_lock, flags);
         return 0;
 }
@@ -502,27 +557,29 @@ static irqreturn_t cmos_interrupt(int irq, void *p)
         u8              rtc_control;
 
         spin_lock(&rtc_lock);
-        /*
-         * In this case it is HPET RTC interrupt handler
-         * calling us, with the interrupt information
-         * passed as arg1, instead of irq.
+
+        /* When the HPET interrupt handler calls us, the interrupt
+         * status is passed as arg1 instead of the irq number.  But
+         * always clear irq status, even when HPET is in the way.
+         *
+         * Note that HPET and RTC are almost certainly out of phase,
+         * giving different IRQ status ...
          */
+        irqstat = CMOS_READ(RTC_INTR_FLAGS);
+        rtc_control = CMOS_READ(RTC_CONTROL);
         if (is_hpet_enabled())
                 irqstat = (unsigned long)irq & 0xF0;
-        else {
-                irqstat = CMOS_READ(RTC_INTR_FLAGS);
-                rtc_control = CMOS_READ(RTC_CONTROL);
-                irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
-        }
+        irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 
         /* All Linux RTC alarms should be treated as if they were oneshot.
          * Similar code may be needed in system wakeup paths, in case the
          * alarm woke the system.
          */
         if (irqstat & RTC_AIE) {
-                rtc_control = CMOS_READ(RTC_CONTROL);
                 rtc_control &= ~RTC_AIE;
                 CMOS_WRITE(rtc_control, RTC_CONTROL);
+                hpet_mask_rtc_irq_bit(RTC_AIE);
+
                 CMOS_READ(RTC_INTR_FLAGS);
         }
         spin_unlock(&rtc_lock);
@@ -629,18 +686,13 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
          * do something about other clock frequencies.
          */
         cmos_rtc.rtc->irq_freq = 1024;
-        if (!hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq))
-                CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
+        hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
+        CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
+
+        /* disable irqs */
+        cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 
-        /* disable irqs.
-         *
-         * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
-         * allegedly some older rtcs need that to handle irqs properly
-         */
         rtc_control = CMOS_READ(RTC_CONTROL);
-        rtc_control &= ~(RTC_PIE | RTC_AIE | RTC_UIE);
-        CMOS_WRITE(rtc_control, RTC_CONTROL);
-        CMOS_READ(RTC_INTR_FLAGS);
 
         spin_unlock_irq(&rtc_lock);
 
@@ -687,7 +739,7 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
                 goto cleanup2;
         }
 
-        pr_info("%s: alarms up to one %s%s\n",
+        pr_info("%s: alarms up to one %s%s%s\n",
                         cmos_rtc.rtc->dev.bus_id,
                         is_valid_irq(rtc_irq)
                                 ?  (cmos_rtc.mon_alrm
@@ -695,8 +747,8 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
                                         : (cmos_rtc.day_alrm
                                                 ? "month" : "day"))
                                 : "no",
-                        cmos_rtc.century ? ", y3k" : ""
-                        );
+                        cmos_rtc.century ? ", y3k" : "",
+                        is_hpet_enabled() ? ", hpet irqs" : "");
 
         return 0;
 
@@ -713,13 +765,8 @@ cleanup0:
 
 static void cmos_do_shutdown(void)
 {
-        unsigned char   rtc_control;
-
         spin_lock_irq(&rtc_lock);
-        rtc_control = CMOS_READ(RTC_CONTROL);
-        rtc_control &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
-        CMOS_WRITE(rtc_control, RTC_CONTROL);
-        CMOS_READ(RTC_INTR_FLAGS);
+        cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
         spin_unlock_irq(&rtc_lock);
 }
 
@@ -760,17 +807,17 @@ static int cmos_suspend(struct device *dev, pm_message_t mesg)
         spin_lock_irq(&rtc_lock);
         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
-                unsigned char   irqstat;
+                unsigned char   mask;
 
                 if (do_wake)
-                        tmp &= ~(RTC_PIE|RTC_UIE);
+                        mask = RTC_IRQMASK & ~RTC_AIE;
                 else
-                        tmp &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
+                        mask = RTC_IRQMASK;
+                tmp &= ~mask;
                 CMOS_WRITE(tmp, RTC_CONTROL);
-                irqstat = CMOS_READ(RTC_INTR_FLAGS);
-                irqstat &= (tmp & RTC_IRQMASK) | RTC_IRQF;
-                if (is_intr(irqstat))
-                        rtc_update_irq(cmos->rtc, 1, irqstat);
+                hpet_mask_rtc_irq_bit(mask);
+
+                cmos_checkintr(cmos, tmp);
         }
         spin_unlock_irq(&rtc_lock);
 
@@ -796,7 +843,8 @@ static int cmos_resume(struct device *dev)
         unsigned char   tmp = cmos->suspend_ctrl;
 
         /* re-enable any irqs previously active */
-        if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
+        if (tmp & RTC_IRQMASK) {
+                unsigned char   mask;
 
                 if (cmos->enabled_wake) {
                         if (cmos->wake_off)
@@ -807,18 +855,28 @@ static int cmos_resume(struct device *dev)
                 }
 
                 spin_lock_irq(&rtc_lock);
-                CMOS_WRITE(tmp, RTC_CONTROL);
-                tmp = CMOS_READ(RTC_INTR_FLAGS);
-                tmp &= (cmos->suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
-                if (is_intr(tmp))
-                        rtc_update_irq(cmos->rtc, 1, tmp);
+                do {
+                        CMOS_WRITE(tmp, RTC_CONTROL);
+                        hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
+
+                        mask = CMOS_READ(RTC_INTR_FLAGS);
+                        mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
+                        if (!is_hpet_enabled() || !is_intr(mask))
+                                break;
+
+                        /* force one-shot behavior if HPET blocked
+                         * the wake alarm's irq
+                         */
+                        rtc_update_irq(cmos->rtc, 1, mask);
+                        tmp &= ~RTC_AIE;
+                        hpet_mask_rtc_irq_bit(RTC_AIE);
+                } while (mask & RTC_AIE);
                 spin_unlock_irq(&rtc_lock);
         }
 
         pr_debug("%s: resume, ctrl %02x\n",
                         cmos_rtc.rtc->dev.bus_id,
-                        cmos->suspend_ctrl);
-
+                        tmp);
 
         return 0;
 }