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Merged
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Feb 15, 2018
Merged

Nuvoton: Rework RTC #6049

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182 changes: 121 additions & 61 deletions targets/TARGET_NUVOTON/TARGET_M451/rtc_api.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@
* See the License for the specific language governing permissions and
* limitations under the License.
*/

#include "rtc_api.h"

#if DEVICE_RTC
Expand All @@ -24,8 +24,65 @@
#include "nu_miscutil.h"
#include "mbed_mktime.h"

#define YEAR0 1900
//#define EPOCH_YR 1970
/* Micro seconds per second */
#define NU_US_PER_SEC 1000000
/* Timer clock per second
*
* NOTE: This dependents on real hardware.
*/
#define NU_RTCCLK_PER_SEC ((CLK->CLKSEL3 & CLK_CLKSEL3_SC0SEL_Msk) ? __LIRC : __LXT)

/* Strategy for implementation of RTC HAL
*
* H/W RTC just supports year range 2000~2099, which cannot fully cover POSIX time (starting since 2970)
* and date time of struct TM (starting since 1900).
*
* To conquer the difficulty, we don't use H/W RTC to keep real date time. Instead, we use it to keep
* elapsed time in seconds since one reference time point. The strategy would be:
*
* 1. Choose DATETIME_HWRTC_ORIGIN (00:00:00 UTC, Saturday, 1 January 2000) as reference time point of H/W RTC.
* 2. t_hwrtc_origin = DATETIME_HWRTC_ORIGIN in POSIX time
* 3. t_hwrtc_elapsed = t_hwrtc_origin + elapsed time since t_hwrtc_origin
* 4. t_write = POSIX time set by rtc_write().
* 5. t_present = rtc_read() = t_write + (t_hwrtc_elapsed - t_hwrtc_origin)
*
* 1900
* |---------------------------------------------------------------------------------|
* 1970 t_write t_present
* |---------|-------|-----------------|---------------------------------------------|
*
* 2000
* |-----------------|---------------------------------------------------------------|
* t_hwrtc_origin t_hwrtc_elapsed
*
*/
/* Start year of struct TM*/
#define NU_TM_YEAR0 1900
/* Start year of POSIX time (set_time()/time()) */
#define NU_POSIX_YEAR0 1970
/* Start year of H/W RTC */
#define NU_HWRTC_YEAR0 2000

/* RTC H/W origin time: 00:00:00 UTC, Saturday, 1 January 2000 */
static const S_RTC_TIME_DATA_T DATETIME_HWRTC_ORIGIN = {
2000, /* Year value, range between 2000 ~ 2099 */
1, /* Month value, range between 1 ~ 12 */
1, /* Day value, range between 1 ~ 31 */
RTC_SATURDAY, /* Day of the week */
0, /* Hour value, range between 0 ~ 23 */
0, /* Minute value, range between 0 ~ 59 */
0, /* Second value, range between 0 ~ 59 */
RTC_CLOCK_24, /* 12-Hour (RTC_CLOCK_12) / 24-Hour (RTC_CLOCK_24) */
0 /* RTC_AM / RTC_PM (used only for 12-Hour) */
};
/* t_hwrtc_origin initialized or not? */
static bool t_hwrtc_origin_inited = 0;
/* POSIX time of DATETIME_HWRTC_ORIGIN (since 00:00:00 UTC, Thursday, 1 January 1970) */
static time_t t_hwrtc_origin = 0;
/* POSIX time set by rtc_write() */
static time_t t_write = 0;
/* Convert date time from H/W RTC to struct TM */
static void rtc_convert_datetime_hwrtc_to_tm(struct tm *datetime_tm, const S_RTC_TIME_DATA_T *datetime_hwrtc);

static const struct nu_modinit_s rtc_modinit = {RTC_0, RTC_MODULE, 0, 0, 0, RTC_IRQn, NULL};

Expand All @@ -34,8 +91,11 @@ void rtc_init(void)
if (rtc_isenabled()) {
return;
}

RTC_Open(NULL);

/* POSIX time origin (00:00:00 UTC, Thursday, 1 January 1970) */
rtc_write(0);
}

void rtc_free(void)
Expand All @@ -50,56 +110,47 @@ int rtc_isenabled(void)
// Enable IP clock
CLK_EnableModuleClock(rtc_modinit.clkidx);
}

// NOTE: Check RTC Init Active flag to support crossing reset cycle.
return !! (RTC->INIT & RTC_INIT_ACTIVE_Msk);
}

/*
struct tm
tm_sec seconds after the minute 0-61
tm_min minutes after the hour 0-59
tm_hour hours since midnight 0-23
tm_mday day of the month 1-31
tm_mon months since January 0-11
tm_year years since 1900
tm_wday days since Sunday 0-6
tm_yday days since January 1 0-365
tm_isdst Daylight Saving Time flag
*/

time_t rtc_read(void)
{
// NOTE: After boot, RTC time registers are not synced immediately, about 1 sec latency.
// RTC time got (through RTC_GetDateAndTime()) in this sec would be last-synced and incorrect.
/* NOTE: After boot, RTC time registers are not synced immediately, about 1 sec latency.
* RTC time got (through RTC_GetDateAndTime()) in this sec would be last-synced and incorrect.
*/
if (! rtc_isenabled()) {
rtc_init();
}

S_RTC_TIME_DATA_T rtc_datetime;
RTC_GetDateAndTime(&rtc_datetime);

struct tm timeinfo;

// Convert struct tm to S_RTC_TIME_DATA_T
timeinfo.tm_year = rtc_datetime.u32Year - YEAR0;
timeinfo.tm_mon = rtc_datetime.u32Month - 1;
timeinfo.tm_mday = rtc_datetime.u32Day;
timeinfo.tm_wday = rtc_datetime.u32DayOfWeek;
timeinfo.tm_hour = rtc_datetime.u32Hour;
if (rtc_datetime.u32TimeScale == RTC_CLOCK_12 && rtc_datetime.u32AmPm == RTC_PM) {
timeinfo.tm_hour += 12;

/* Used for intermediary between date time of H/W RTC and POSIX time */
struct tm datetime_tm;

if (! t_hwrtc_origin_inited) {
t_hwrtc_origin_inited = 1;

/* Convert date time from H/W RTC to struct TM */
rtc_convert_datetime_hwrtc_to_tm(&datetime_tm, &DATETIME_HWRTC_ORIGIN);
/* Convert date time of struct TM to POSIX time */
if (! _rtc_maketime(&datetime_tm, &t_hwrtc_origin, RTC_FULL_LEAP_YEAR_SUPPORT)) {
return 0;
}
}
timeinfo.tm_min = rtc_datetime.u32Minute;
timeinfo.tm_sec = rtc_datetime.u32Second;

// Convert to timestamp
time_t t;
if (_rtc_maketime(&timeinfo, &t, RTC_FULL_LEAP_YEAR_SUPPORT) == false) {
S_RTC_TIME_DATA_T hwrtc_datetime_2K_present;
RTC_GetDateAndTime(&hwrtc_datetime_2K_present);
/* Convert date time from H/W RTC to struct TM */
rtc_convert_datetime_hwrtc_to_tm(&datetime_tm, &hwrtc_datetime_2K_present);
/* Convert date time of struct TM to POSIX time */
time_t t_hwrtc_elapsed;
if (! _rtc_maketime(&datetime_tm, &t_hwrtc_elapsed, RTC_FULL_LEAP_YEAR_SUPPORT)) {
return 0;
}

return t;
/* Present time in POSIX time */
time_t t_present = t_write + (t_hwrtc_elapsed - t_hwrtc_origin);
return t_present;
}

void rtc_write(time_t t)
Expand All @@ -108,28 +159,37 @@ void rtc_write(time_t t)
rtc_init();
}

// Convert timestamp to struct tm
struct tm timeinfo;
if (_rtc_localtime(t, &timeinfo, RTC_FULL_LEAP_YEAR_SUPPORT) == false) {
return;
}
t_write = t;

S_RTC_TIME_DATA_T rtc_datetime;

// Convert S_RTC_TIME_DATA_T to struct tm
rtc_datetime.u32Year = timeinfo.tm_year + YEAR0;
rtc_datetime.u32Month = timeinfo.tm_mon + 1;
rtc_datetime.u32Day = timeinfo.tm_mday;
rtc_datetime.u32DayOfWeek = timeinfo.tm_wday;
rtc_datetime.u32Hour = timeinfo.tm_hour;
rtc_datetime.u32Minute = timeinfo.tm_min;
rtc_datetime.u32Second = timeinfo.tm_sec;
rtc_datetime.u32TimeScale = RTC_CLOCK_24;

// NOTE: Timing issue with write to RTC registers. This delay is empirical, not rational.
RTC_SetDateAndTime(&rtc_datetime);
//nu_nop(6000);
wait_us(100);
RTC_SetDateAndTime((S_RTC_TIME_DATA_T *) &DATETIME_HWRTC_ORIGIN);
/* NOTE: When engine is clocked by low power clock source (LXT/LIRC), we need to wait for 3 engine clocks. */
wait_us((NU_US_PER_SEC / NU_RTCCLK_PER_SEC) * 3);
}

/*
struct tm
tm_sec seconds after the minute 0-61
tm_min minutes after the hour 0-59
tm_hour hours since midnight 0-23
tm_mday day of the month 1-31
tm_mon months since January 0-11
tm_year years since 1900
tm_wday days since Sunday 0-6
tm_yday days since January 1 0-365
tm_isdst Daylight Saving Time flag
*/
static void rtc_convert_datetime_hwrtc_to_tm(struct tm *datetime_tm, const S_RTC_TIME_DATA_T *datetime_hwrtc)
{
datetime_tm->tm_year = datetime_hwrtc->u32Year - NU_TM_YEAR0;
datetime_tm->tm_mon = datetime_hwrtc->u32Month - 1;
datetime_tm->tm_mday = datetime_hwrtc->u32Day;
datetime_tm->tm_wday = datetime_hwrtc->u32DayOfWeek;
datetime_tm->tm_hour = datetime_hwrtc->u32Hour;
if (datetime_hwrtc->u32TimeScale == RTC_CLOCK_12 && datetime_hwrtc->u32AmPm == RTC_PM) {
datetime_tm->tm_hour += 12;
}
datetime_tm->tm_min = datetime_hwrtc->u32Minute;
datetime_tm->tm_sec = datetime_hwrtc->u32Second;
}

#endif
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