Martin Kojtal
forked
Diff: targets/TARGET_Maxim/TARGET_MAX32630/rtc_api.c
- Revision:
- 157:ff67d9f36b67
- Child:
- 165:e614a9f1c9e2
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_Maxim/TARGET_MAX32630/rtc_api.c Thu Feb 02 17:01:33 2017 +0000
@@ -0,0 +1,253 @@
+/*******************************************************************************
+ * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
+ * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the name of Maxim Integrated
+ * Products, Inc. shall not be used except as stated in the Maxim Integrated
+ * Products, Inc. Branding Policy.
+ *
+ * The mere transfer of this software does not imply any licenses
+ * of trade secrets, proprietary technology, copyrights, patents,
+ * trademarks, maskwork rights, or any other form of intellectual
+ * property whatsoever. Maxim Integrated Products, Inc. retains all
+ * ownership rights.
+ *******************************************************************************
+ */
+
+#include "rtc_api.h"
+#include "lp_ticker_api.h"
+#include "rtc.h"
+#include "lp.h"
+
+#define PRESCALE_VAL RTC_PRESCALE_DIV_2_0 // Set the divider for the 4kHz clock
+#define SHIFT_AMT (RTC_PRESCALE_DIV_2_12 - PRESCALE_VAL)
+
+#define WINDOW 1000
+
+static int rtc_inited = 0;
+static volatile uint32_t overflow_cnt = 0;
+
+static uint64_t rtc_read64(void);
+
+//******************************************************************************
+static void overflow_handler(void)
+{
+ overflow_cnt++;
+ RTC_ClearFlags(MXC_F_RTC_FLAGS_ASYNC_CLR_FLAGS);
+}
+
+//******************************************************************************
+void rtc_init(void)
+{
+ if (rtc_inited) {
+ return;
+ }
+ rtc_inited = 1;
+
+ overflow_cnt = 0;
+
+ /* Enable power for RTC for all LPx states */
+ MXC_PWRSEQ->reg0 |= (MXC_F_PWRSEQ_REG0_PWR_RTCEN_RUN |
+ MXC_F_PWRSEQ_REG0_PWR_RTCEN_SLP);
+
+ /* Enable clock to synchronizers */
+ CLKMAN_SetClkScale(CLKMAN_CLK_SYNC, CLKMAN_SCALE_DIV_1);
+
+ // Prepare interrupt handlers
+ NVIC_SetVector(RTC0_IRQn, lp_ticker_irq_handler);
+ NVIC_EnableIRQ(RTC0_IRQn);
+ NVIC_SetVector(RTC3_IRQn, overflow_handler);
+ NVIC_EnableIRQ(RTC3_IRQn);
+
+ // Enable wakeup on RTC rollover
+ LP_ConfigRTCWakeUp(0, 0, 0, 1);
+
+ /* RTC registers are only reset on a power cycle. Do not reconfigure the RTC
+ * if it is already running.
+ */
+ if (!RTC_IsActive()) {
+ rtc_cfg_t cfg = {0};
+ cfg.prescaler = PRESCALE_VAL;
+ cfg.snoozeMode = RTC_SNOOZE_DISABLE;
+
+ int retval = RTC_Init(&cfg);
+ MBED_ASSERT(retval == E_NO_ERROR);
+
+ RTC_EnableINT(MXC_F_RTC_FLAGS_OVERFLOW);
+ RTC_Start();
+ }
+}
+
+//******************************************************************************
+void lp_ticker_init(void)
+{
+ rtc_init();
+}
+
+//******************************************************************************
+void rtc_free(void)
+{
+ if (RTC_IsActive()) {
+ // Clear and disable RTC
+ MXC_RTCTMR->ctrl |= MXC_F_RTC_CTRL_CLEAR;
+ RTC_Stop();
+ }
+}
+
+//******************************************************************************
+int rtc_isenabled(void)
+{
+ return RTC_IsActive();
+}
+
+//******************************************************************************
+time_t rtc_read(void)
+{
+ uint32_t ovf_cnt_1, ovf_cnt_2, timer_cnt;
+ uint32_t ovf1, ovf2;
+
+ // Make sure RTC is setup before trying to read
+ if (!rtc_inited) {
+ rtc_init();
+ }
+
+ // Ensure coherency between overflow_cnt and timer
+ do {
+ ovf_cnt_1 = overflow_cnt;
+ ovf1 = RTC_GetFlags() & MXC_F_RTC_FLAGS_OVERFLOW;
+ timer_cnt = RTC_GetCount();
+ ovf2 = RTC_GetFlags() & MXC_F_RTC_FLAGS_OVERFLOW;
+ ovf_cnt_2 = overflow_cnt;
+ } while ((ovf_cnt_1 != ovf_cnt_2) || (ovf1 != ovf2));
+
+ // Account for an unserviced interrupt
+ if (ovf1) {
+ ovf_cnt_1++;
+ }
+
+ return (timer_cnt >> SHIFT_AMT) + (ovf_cnt_1 << (32 - SHIFT_AMT));
+}
+
+//******************************************************************************
+static uint64_t rtc_read64(void)
+{
+ uint32_t ovf_cnt_1, ovf_cnt_2, timer_cnt;
+ uint32_t ovf1, ovf2;
+ uint64_t current_us;
+
+ // Make sure RTC is setup before trying to read
+ if (!rtc_inited) {
+ rtc_init();
+ }
+
+ // Ensure coherency between overflow_cnt and timer
+ do {
+ ovf_cnt_1 = overflow_cnt;
+ ovf1 = RTC_GetFlags() & MXC_F_RTC_FLAGS_OVERFLOW;
+ timer_cnt = RTC_GetCount();
+ ovf2 = RTC_GetFlags() & MXC_F_RTC_FLAGS_OVERFLOW;
+ ovf_cnt_2 = overflow_cnt;
+ } while ((ovf_cnt_1 != ovf_cnt_2) || (ovf1 != ovf2));
+
+ // Account for an unserviced interrupt
+ if (ovf1) {
+ ovf_cnt_1++;
+ }
+
+ current_us = (((uint64_t)timer_cnt * 1000000) >> SHIFT_AMT) + (((uint64_t)ovf_cnt_1 * 1000000) << (32 - SHIFT_AMT));
+
+ return current_us;
+}
+
+//******************************************************************************
+void rtc_write(time_t t)
+{
+ // Make sure RTC is setup before accessing
+ if (!rtc_inited) {
+ rtc_init();
+ }
+
+ RTC_Stop();
+ RTC_SetCount(t << SHIFT_AMT);
+ overflow_cnt = t >> (32 - SHIFT_AMT);
+ RTC_Start();
+}
+
+//******************************************************************************
+void lp_ticker_set_interrupt(timestamp_t timestamp)
+{
+ uint32_t comp_value;
+ uint64_t curr_ts64;
+ uint64_t ts64;
+
+ // Note: interrupts are disabled before this function is called.
+
+ // Disable the alarm while it is prepared
+ RTC_DisableINT(MXC_F_RTC_INTEN_COMP0);
+
+ curr_ts64 = rtc_read64();
+ ts64 = (uint64_t)timestamp | (curr_ts64 & 0xFFFFFFFF00000000ULL);
+
+ // If this event is older than a recent window, it must be in the future
+ if ((ts64 < (curr_ts64 - WINDOW)) && ((curr_ts64 - WINDOW) < curr_ts64)) {
+ ts64 += 0x100000000ULL;
+ }
+
+ uint32_t timer = RTC_GetCount();
+ if (ts64 <= curr_ts64) {
+ // This event has already occurred. Set the alarm to expire immediately.
+ comp_value = timer + 1;
+ } else {
+ comp_value = (ts64 << SHIFT_AMT) / 1000000;
+ }
+
+ // Ensure that the compare value is far enough in the future to guarantee the interrupt occurs.
+ if ((comp_value < (timer + 2)) && (comp_value > (timer - 10))) {
+ comp_value = timer + 2;
+ }
+
+ MXC_RTCTMR->comp[0] = comp_value;
+ MXC_RTCTMR->flags = MXC_F_RTC_FLAGS_ASYNC_CLR_FLAGS;
+ RTC_EnableINT(MXC_F_RTC_INTEN_COMP0);
+
+ // Enable wakeup from RTC
+ LP_ConfigRTCWakeUp(1, 0, 0, 1);
+
+ // Wait for pending transactions
+ while (MXC_RTCTMR->ctrl & MXC_F_RTC_CTRL_PENDING);
+}
+
+//******************************************************************************
+inline void lp_ticker_disable_interrupt(void)
+{
+ RTC_DisableINT(MXC_F_RTC_INTEN_COMP0);
+}
+
+//******************************************************************************
+inline void lp_ticker_clear_interrupt(void)
+{
+ RTC_ClearFlags(MXC_F_RTC_FLAGS_ASYNC_CLR_FLAGS);
+}
+
+//******************************************************************************
+inline uint32_t lp_ticker_read(void)
+{
+ return rtc_read64();
+}