imx233: implement alarm wake up

This adds the application part of alarm wake up. On some targets
like the Fuze+, it will also require a bootloader change to make
sure that the device doesn't power down on alarm wake up (for
example on the Fuze+ the bootloader requires the power button to
be hold sufficiently long, thus preventing alarm wake up to work)

Change-Id: I5d01957852355fddbd48110d3d75a5533f07879e

firmware/drivers/rtc/rtc_imx233.c

@@ -28,15 +28,18 @@
 
 #define YEAR1980    315532800   /* 1980/1/1 00:00:00 in UTC */
 
+#if defined(SANSA_FUZEPLUS) || defined(CREATIVE_ZENXFI3)
+#define USE_PERSISTENT
+#endif
+
 void rtc_init(void)
 {
     /* rtc-imx233 is initialized by the system */
 }
 
-int rtc_read_datetime(struct tm *tm)
+static void seconds_to_datetime(uint32_t seconds, struct tm *tm)
 {
-    uint32_t seconds = imx233_rtc_read_seconds();
-#if defined(SANSA_FUZEPLUS) || defined(CREATIVE_ZENXFI3)
+#ifdef USE_PERSISTENT
     /* The OF uses PERSISTENT2 register to keep the adjustment and only changes
      * SECONDS if necessary. */
     seconds += imx233_rtc_read_persistent(2);
@@ -47,7 +50,11 @@ int rtc_read_datetime(struct tm *tm)
 #endif
 
     gmtime_r(&seconds, tm);
+}
 
+int rtc_read_datetime(struct tm *tm)
+{
+    seconds_to_datetime(imx233_rtc_read_seconds(), tm);
     return 0;
 }
 
@@ -57,7 +64,7 @@ int rtc_write_datetime(const struct tm *tm)
 
     seconds = mktime((struct tm *)tm);
 
-#if defined(SANSA_FUZEPLUS) || defined(CREATIVE_ZENXFI3)
+#ifdef USE_PERSISTENT
     /* The OF uses PERSISTENT2 register to keep the adjustment and only changes
      * SECONDS if necessary.
      * NOTE: the OF uses this mechanism to prevent roll back in time. Although
@@ -75,28 +82,58 @@ int rtc_write_datetime(const struct tm *tm)
 
 void rtc_set_alarm(int h, int m)
 {
-    (void) h;
-    (void) m;
+    /* transform alarm time to absolute time */
+    struct tm tm;
+    seconds_to_datetime(imx233_rtc_read_seconds(), &tm);
+    /* if same date and hour/min is in the past, advance one day */
+    if(h < tm.tm_hour || (h == tm.tm_hour && m <= tm.tm_min))
+        seconds_to_datetime(imx233_rtc_read_seconds() + 3600 * 60, &tm);
+    tm.tm_hour = h;
+    tm.tm_min = m;
+    tm.tm_sec = 0;
+
+    uint32_t seconds = mktime(&tm);
+#ifdef USE_PERSISTENT
+    imx233_rtc_write_alarm(seconds - imx233_rtc_read_persistent(2));
+#else
+    imx233_rtc_write_alarm(seconds - YEAR1980);
+#endif
 }
 
 void rtc_get_alarm(int *h, int *m)
 {
-    (void) h;
-    (void) m;
+    struct tm tm;
+    seconds_to_datetime(imx233_rtc_read_alarm(), &tm);
+    *m = tm.tm_min;
+    *h = tm.tm_hour;
 }
 
 void rtc_enable_alarm(bool enable)
 {
-    (void) enable;
+    BF_CLR(RTC_CTRL, ALARM_IRQ_EN);
+    BF_CLR(RTC_CTRL, ALARM_IRQ);
+    uint32_t val = imx233_rtc_read_persistent(0);
+    BF_WRX(val, RTC_PERSISTENT0, ALARM_EN, enable);
+    BF_WRX(val, RTC_PERSISTENT0, ALARM_WAKE_EN, enable);
+    BF_WRX(val, RTC_PERSISTENT0, ALARM_WAKE, 0);
+    imx233_rtc_write_persistent(0, val);
 }
 
+/**
+ * Check if alarm caused unit to start.
+ */
 bool rtc_check_alarm_started(bool release_alarm)
 {
-    (void) release_alarm;
-    return false;
+    bool res = BF_RDX(imx233_rtc_read_persistent(0), RTC_PERSISTENT0, ALARM_WAKE);
+    if(release_alarm)
+        rtc_enable_alarm(false);
+    return res;
 }
 
+/**
+ * Checks if an alarm interrupt has triggered since last we checked.
+ */
 bool rtc_check_alarm_flag(void)
 {
-    return false;
+    return BF_RD(RTC_CTRL, ALARM_IRQ);
 }

firmware/target/arm/imx233/rtc-imx233.c

@@ -38,6 +38,11 @@ void imx233_rtc_write_persistent(int idx, uint32_t val)
     imx233_rtc_write_reg(&HW_RTC_PERSISTENTn(idx), val);
 }
 
+void imx233_rtc_write_alarm(uint32_t seconds)
+{
+    imx233_rtc_write_reg(&HW_RTC_ALARM, seconds);
+}
+
 struct imx233_rtc_info_t imx233_rtc_get_info(void)
 {
     struct imx233_rtc_info_t info;
@@ -45,5 +50,10 @@ struct imx233_rtc_info_t imx233_rtc_get_info(void)
     info.seconds = HW_RTC_SECONDS;
     for(int i = 0; i < 6; i++)
         info.persistent[i] = HW_RTC_PERSISTENTn(i);
+    info.alarm = imx233_rtc_read_alarm();
+    info.alarm_en = BF_RD(RTC_PERSISTENT0, ALARM_EN);
+    info.alarm_wake_en = BF_RD(RTC_PERSISTENT0, ALARM_WAKE_EN);
+    info.alarm_wake = BF_RD(RTC_PERSISTENT0, ALARM_WAKE);
+    info.alarm_irq = BF_RD(RTC_CTRL, ALARM_IRQ);
     return info;
 }

firmware/target/arm/imx233/rtc-imx233.h

@@ -33,6 +33,8 @@ struct imx233_rtc_info_t
 {
     uint32_t seconds;
     uint32_t persistent[6];
+    uint32_t alarm;
+    bool alarm_en, alarm_wake_en, alarm_wake, alarm_irq;
 };
 
 static inline void imx233_rtc_init(void)
@@ -64,8 +66,14 @@ static inline void imx233_rtc_enable_msec_irq(bool enable)
         BF_CLR(RTC_CTRL, ONEMSEC_IRQ_EN);
 }
 
+static inline uint32_t imx233_rtc_read_alarm(void)
+{
+    return HW_RTC_ALARM;
+}
+
 void imx233_rtc_write_seconds(uint32_t seconds);
 void imx233_rtc_write_persistent(int idx, uint32_t val);
+void imx233_rtc_write_alarm(uint32_t seconds);
 
 struct imx233_rtc_info_t imx233_rtc_get_info(void);