/************************************************************************************ * arch/arm/src/stm32/stm32f20xxx_rtc.c * * Copyright (C) 2012 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ************************************************************************************/ /************************************************************************************ * Included Files ************************************************************************************/ #include #include #include #include #include #include #include #include #include "up_arch.h" #include "stm32_rtc.h" #ifdef CONFIG_RTC /************************************************************************************ * Pre-processor Definitions ************************************************************************************/ /* Configuration ********************************************************************/ /* This RTC implementation supports only date/time RTC hardware */ #ifndef CONFIG_RTC_DATETIME # error "CONFIG_RTC_DATETIME must be set to use this driver" #endif #ifdef CONFIG_RTC_HIRES # error "CONFIG_RTC_HIRES must NOT be set with this driver" #endif #ifndef CONFIG_STM32_PWR # error "CONFIG_STM32_PWR must selected to use this driver" #endif #ifndef CONFIG_DEBUG # undef CONFIG_DEBUG_RTC #endif /* Constants ************************************************************************/ #define SYNCHRO_TIMEOUT (0x00020000) #define INITMODE_TIMEOUT (0x00010000) #define RTC_MAGIC (0xfacefeed) #define RTC_PREDIV_S (0xff) #define RTC_PREDIV_A (0x7f) /* Debug ****************************************************************************/ #ifdef CONFIG_DEBUG_RTC # define rtcdbg dbg # define rtcvdbg vdbg # define rtclldbg lldbg # define rtcllvdbg llvdbg #else # define rtcdbg(x...) # define rtcvdbg(x...) # define rtclldbg(x...) # define rtcllvdbg(x...) #endif /************************************************************************************ * Private Types ************************************************************************************/ /************************************************************************************ * Private Data ************************************************************************************/ /* Callback to use when the alarm expires */ #ifdef CONFIG_RTC_ALARM static alarmcb_t g_alarmcb; #endif /************************************************************************************ * Public Data ************************************************************************************/ /* g_rtc_enabled is set true after the RTC has successfully initialized */ volatile bool g_rtc_enabled = false; /************************************************************************************ * Private Functions ************************************************************************************/ /************************************************************************************ * Name: rtc_dumpregs * * Description: * Disable RTC write protection * * Input Parameters: * None * * Returned Value: * None * ************************************************************************************/ #ifdef CONFIG_DEBUG_RTC static void rtc_dumpregs(FAR const char *msg) { rtclldbg("%s:\n", msg); rtclldbg(" TR: %08x\n", getreg32(STM32_RTC_TR)); rtclldbg(" DR: %08x\n", getreg32(STM32_RTC_DR)); rtclldbg(" CR: %08x\n", getreg32(STM32_RTC_CR)); rtclldbg(" ISR: %08x\n", getreg32(STM32_RTC_ISR)); rtclldbg(" PRER: %08x\n", getreg32(STM32_RTC_PRER)); rtclldbg(" WUTR: %08x\n", getreg32(STM32_RTC_WUTR)); rtclldbg(" CALIBR: %08x\n", getreg32(STM32_RTC_CALIBR)); rtclldbg(" ALRMAR: %08x\n", getreg32(STM32_RTC_ALRMAR)); rtclldbg(" ALRMBR: %08x\n", getreg32(STM32_RTC_ALRMBR)); rtclldbg(" SHIFTR: %08x\n", getreg32(STM32_RTC_SHIFTR)); rtclldbg(" TSTR: %08x\n", getreg32(STM32_RTC_TSTR)); rtclldbg(" TSDR: %08x\n", getreg32(STM32_RTC_TSDR)); rtclldbg(" TSSSR: %08x\n", getreg32(STM32_RTC_TSSSR)); rtclldbg(" CALR: %08x\n", getreg32(STM32_RTC_CALR)); rtclldbg(" TAFCR: %08x\n", getreg32(STM32_RTC_TAFCR)); rtclldbg("ALRMASSR: %08x\n", getreg32(STM32_RTC_ALRMASSR)); rtclldbg("ALRMBSSR: %08x\n", getreg32(STM32_RTC_ALRMBSSR)); rtclldbg(" BK0: %08x\n", getreg32(STM32_RTC_BK0R)); } #else # define rtc_dumpregs(msg) #endif /************************************************************************************ * Name: rtc_dumptime * * Description: * Disable RTC write protection * * Input Parameters: * None * * Returned Value: * None * ************************************************************************************/ #ifdef CONFIG_DEBUG_RTC static void rtc_dumptime(FAR struct tm *tp, FAR const char *msg) { rtclldbg("%s:\n", msg); rtclldbg(" tm_sec: %08x\n", tp->tm_sec); rtclldbg(" tm_min: %08x\n", tp->tm_min); rtclldbg(" tm_hour: %08x\n", tp->tm_hour); rtclldbg(" tm_mday: %08x\n", tp->tm_mday); rtclldbg(" tm_mon: %08x\n", tp->tm_mon); rtclldbg(" tm_year: %08x\n", tp->tm_year); } #else # define rtc_dumptime(tp, msg) #endif /************************************************************************************ * Name: rtc_wprunlock * * Description: * Disable RTC write protection * * Input Parameters: * None * * Returned Value: * None * ************************************************************************************/ static void rtc_wprunlock(void) { /* The following steps are required to unlock the write protection on all the * RTC registers (except for RTC_ISR[13:8], RTC_TAFCR, and RTC_BKPxR). * * 1. Write 0xCA into the RTC_WPR register. * 2. Write 0x53 into the RTC_WPR register. * * Writing a wrong key reactivates the write protection. */ putreg32(0xca, STM32_RTC_WPR); putreg32(0x53, STM32_RTC_WPR); } /************************************************************************************ * Name: rtc_wprunlock * * Description: * Enable RTC write protection * * Input Parameters: * None * * Returned Value: * None * ************************************************************************************/ static inline void rtc_wprlock(void) { /* Writing any wrong key reactivates the write protection. */ putreg32(0xff, STM32_RTC_WPR); } /************************************************************************************ * Name: rtc_synchwait * * Description: * Waits until the RTC Time and Date registers (RTC_TR and RTC_DR) are * synchronized with RTC APB clock. * * Input Parameters: * None * * Returned Value: * Zero (OK) on success; a negated errno on failure * ************************************************************************************/ static int rtc_synchwait(void) { volatile uint32_t timeout; uint32_t regval; int ret; /* Disable the write protection for RTC registers */ rtc_wprunlock(); /* Clear Registers synchronization flag (RSF) */ regval = getreg32(STM32_RTC_ISR); regval &= ~RTC_ISR_RSF; putreg32(regval, STM32_RTC_ISR); /* Now wait the registers to become synchronised */ ret = -ETIMEDOUT; for (timeout = 0; timeout < SYNCHRO_TIMEOUT; timeout++) { regval = getreg32(STM32_RTC_ISR); if ((regval & RTC_ISR_RSF) != 0) { /* Synchronized */ ret = OK; break; } } /* Re-enable the write protection for RTC registers */ rtc_wprlock(); return ret; } /************************************************************************************ * Name: rtc_enterinit * * Description: * Enter RTC initialization mode. * * Input Parameters: * None * * Returned Value: * Zero (OK) on success; a negated errno on failure * ************************************************************************************/ static int rtc_enterinit(void) { volatile uint32_t timeout; uint32_t regval; int ret; /* Check if the Initialization mode is already set */ regval = getreg32(STM32_RTC_ISR); ret = OK; if ((regval & RTC_ISR_INITF) == 0) { /* Set the Initialization mode */ putreg32(RTC_ISR_INIT, STM32_RTC_ISR); /* Wait until the RTC is in the INIT state (or a timeout occurs) */ ret = -ETIMEDOUT; for (timeout = 0; timeout < INITMODE_TIMEOUT; timeout++) { regval = getreg32(STM32_RTC_ISR); if ((regval & RTC_ISR_INITF) != 0) { ret = OK; break; } } } return ret; } /************************************************************************************ * Name: rtc_exitinit * * Description: * Exit RTC initialization mode. * * Input Parameters: * None * * Returned Value: * Zero (OK) on success; a negated errno on failure * ************************************************************************************/ static void rtc_exitinit(void) { uint32_t regval; regval = getreg32(STM32_RTC_ISR); regval &= ~(RTC_ISR_INIT); putreg32(regval, STM32_RTC_ISR); } /************************************************************************************ * Name: rtc_bin2bcd * * Description: * Converts a 2 digit binary to BCD format * * Input Parameters: * value - The byte to be converted. * * Returned Value: * The value in BCD representation * ************************************************************************************/ static uint32_t rtc_bin2bcd(int value) { uint32_t msbcd = 0; while (value >= 10) { msbcd++; value -= 10; } return (msbcd << 4) | value; } /************************************************************************************ * Name: rtc_bin2bcd * * Description: * Convert from 2 digit BCD to binary. * * Input Parameters: * value - The BCD value to be converted. * * Returned Value: * The value in binary representation * ************************************************************************************/ static int rtc_bcd2bin(uint32_t value) { uint32_t tens = (value >> 4) * 10; return (int)(tens + (value & 0x0f)); } /************************************************************************************ * Name: rtc_setup * * Description: * Performs first time configuration of the RTC. A special value written into * back-up register 0 will prevent this function from being called on sub-sequent * resets or power up. * * Input Parameters: * None * * Returned Value: * Zero (OK) on success; a negated errno on failure * ************************************************************************************/ static int rtc_setup(void) { uint32_t regval; int ret; /* Enable the External Low-Speed (LSE) Oscillator setup the LSE as the RTC clock\ * source, and enable the RTC. */ stm32_rcc_enablelse(); /* Wait for the RTC Time and Date registers to be synchronized with RTC APB * clock. */ ret = rtc_synchwait(); if (ret == OK) { /* Disable the write protection for RTC registers */ rtc_wprunlock(); /* Set Initialization mode */ ret = rtc_enterinit(); if (ret == OK) { /* Set the 24 hour format by clearing the FMT bit in the RTC * control register */ regval = getreg32(STM32_RTC_CR); regval &= ~RTC_CR_FMT; putreg32(regval, STM32_RTC_CR); /* Configure RTC pre-scaler to the required, default values for * use with the 32.768 KHz LSE clock: */ putreg32(((uint32_t)0xff << RTC_PRER_PREDIV_S_SHIFT) | ((uint32_t)0x7f << RTC_PRER_PREDIV_A_SHIFT), STM32_RTC_PRER); /* Exit RTC initialization mode */ rtc_exitinit(); } /* Re-enable the write protection for RTC registers */ rtc_wprlock(); } return ret; } /************************************************************************************ * Name: rtc_resume * * Description: * Called when the RTC was already initialized on a previous power cycle. This * just brings the RTC back into full operation. * * Input Parameters: * None * * Returned Value: * Zero (OK) on success; a negated errno on failure * ************************************************************************************/ static int rtc_resume(void) { #ifdef CONFIG_RTC_ALARM uint32_t regval; #endif int ret; /* Wait for the RTC Time and Date registers to be syncrhonized with RTC APB * clock. */ ret = rtc_synchwait(); /* Clear the RTC alarm flags */ #ifdef CONFIG_RTC_ALARM regval = getreg32(STM32_RTC_ISR); regval &= ~(RTC_ISR_ALRAF|RTC_ISR_ALRBF); putreg32(regval, STM32_RTC_ISR); /* Clear the EXTI Line 17 Pending bit (Connected internally to RTC Alarm) */ putreg32((1 << 17), STM32_EXTI_PR); #endif return ret; } /************************************************************************************ * Name: rtc_interrupt * * Description: * RTC interrupt service routine * * Input Parameters: * irq - The IRQ number that generated the interrupt * context - Architecture specific register save information. * * Returned Value: * Zero (OK) on success; A negated errno value on failure. * ************************************************************************************/ #if CONFIG_RTC_ALARM static int rtc_interrupt(int irq, void *context) { #warning "Missing logic" return OK; } #endif /************************************************************************************ * Public Functions ************************************************************************************/ /************************************************************************************ * Name: up_rtcinitialize * * Description: * Initialize the hardware RTC per the selected configuration. This function is * called once during the OS initialization sequence * * Input Parameters: * None * * Returned Value: * Zero (OK) on success; a negated errno on failure * ************************************************************************************/ int up_rtcinitialize(void) { uint32_t regval; int ret; rtc_dumpregs("On reset"); /* Clocking for the PWR block must be provided. However, this is done * unconditionally in stm32f40xxx_rcc.c on power up. This done unconditionally * because the PWR block is also needed to set the internal voltage regulator for * maximum performance. */ /* Enable access to the backup domain (RTC registers, RTC backup data registers * and backup SRAM). */ stm32_pwr_enablebkp(); /* Check if the one-time initialization of the RTC has already been performed. * We can determine this by checking if the magic number has been writing to * to back-up date register DR0. */ regval = getreg32(STM32_RTC_BK0R); if (regval != RTC_MAGIC) { /* Perform the one-time setup of the LSE clocking to the RTC */ ret = rtc_setup(); /* Remember that the RTC is initialized */ putreg32(RTC_MAGIC, STM32_RTC_BK0R); } else { /* RTC already set-up, just resume normal operation */ ret = rtc_resume(); } /* Configure RTC interrupt to catch alarm interrupts. All RTC interrupts are * connected to the EXTI controller. To enable the RTC Alarm interrupt, the * following sequence is required: * * 1. Configure and enable the EXTI Line 17 in interrupt mode and select the * rising edge sensitivity. * 2. Configure and enable the RTC_Alarm IRQ channel in the NVIC. * 3. Configure the RTC to generate RTC alarms (Alarm A or Alarm B). */ #ifdef CONFIG_RTC_ALARM # warning "Missing EXTI setup logic" /* Then attach the ALARM interrupt handler */ irq_attach(STM32_IRQ_RTC, rtc_interrupt); up_enable_irq(STM32_IRQ_RTC); #endif g_rtc_enabled = true; rtc_dumpregs("After Initialzation"); return OK; } /************************************************************************************ * Name: up_rtc_getdatetime * * Description: * Get the current date and time from the date/time RTC. This interface * is only supported by the date/time RTC hardware implementation. * It is used to replace the system timer. It is only used by the RTOS during * intialization to set up the system time when CONFIG_RTC and CONFIG_RTC_DATETIME * are selected (and CONFIG_RTC_HIRES is not). * * NOTE: Some date/time RTC hardware is capability of sub-second accuracy. That * sub-second accuracy is lost in this interface. However, since the system time * is reinitialized on each power-up/reset, there will be no timing inaccuracy in * the long run. * * Input Parameters: * tp - The location to return the high resolution time value. * * Returned Value: * Zero (OK) on success; a negated errno on failure * ************************************************************************************/ int up_rtc_getdatetime(FAR struct tm *tp) { uint32_t dr; uint32_t tr; uint32_t tmp; /* Sample the data time registers. There is a race condition here... If we sample * the time just before midnight on December 31, the date could be wrong because * the day rolled over while were sampling. */ do { dr = getreg32(STM32_RTC_DR); tr = getreg32(STM32_RTC_TR); tmp = getreg32(STM32_RTC_DR); } while (tmp != dr); rtc_dumpregs("Reading Time"); /* Convert the RTC time to fields in struct tm format. All of the STM32 * All of the ranges of values correspond between struct tm and the time * register. */ tmp = (tr & (RTC_TR_SU_MASK|RTC_TR_ST_MASK)) >> RTC_TR_SU_SHIFT; tp->tm_sec = rtc_bcd2bin(tmp); tmp = (tr & (RTC_TR_MNU_MASK|RTC_TR_MNT_MASK)) >> RTC_TR_MNU_SHIFT; tp->tm_min = rtc_bcd2bin(tmp); tmp = (tr & (RTC_TR_HU_MASK|RTC_TR_HT_MASK)) >> RTC_TR_HU_SHIFT; tp->tm_hour = rtc_bcd2bin(tmp); /* Now convert the RTC date to fields in struct tm format: * Days: 1-31 match in both cases. * Month: STM32 is 1-12, struct tm is 0-11. * Years: STM32 is 00-99, struct tm is years since 1900. * * Issue: I am not sure what the STM32 years mean. Are these the * years 2000-2099? I'll assume so. */ tmp = (dr & (RTC_DR_DU_MASK|RTC_DR_DT_MASK)) >> RTC_DR_DU_SHIFT; tp->tm_mday = rtc_bcd2bin(tmp); tmp = (dr & (RTC_DR_MU_MASK|RTC_DR_MT)) >> RTC_DR_MU_SHIFT; tp->tm_mon = rtc_bcd2bin(tmp) - 1; tmp = (dr & (RTC_DR_YU_MASK|RTC_DR_YT_MASK)) >> RTC_DR_YU_SHIFT; tp->tm_year = rtc_bcd2bin(tmp) + 100; rtc_dumptime(tp, "Returning"); return OK; } /************************************************************************************ * Name: up_rtc_settime * * Description: * Set the RTC to the provided time. All RTC implementations must be able to * set their time based on a standard timespec. * * Input Parameters: * tp - the time to use * * Returned Value: * Zero (OK) on success; a negated errno on failure * ************************************************************************************/ int up_rtc_settime(FAR const struct timespec *tp) { FAR struct tm newtime; uint32_t tr; uint32_t dr; int ret; /* Break out the time values (not that the time is set only to units of seconds) */ (void)gmtime_r(&tp->tv_sec, &newtime); rtc_dumptime(&newtime, "Setting time"); /* Then write the broken out values to the RTC */ /* Convert the struct tm format to RTC time register fields. All of the STM32 * All of the ranges of values correspond between struct tm and the time * register. */ tr = (rtc_bin2bcd(newtime.tm_sec) << RTC_TR_SU_SHIFT) | (rtc_bin2bcd(newtime.tm_min) << RTC_TR_MNU_SHIFT) | (rtc_bin2bcd(newtime.tm_hour) << RTC_TR_HU_SHIFT); tr &= ~RTC_TR_RESERVED_BITS; /* Now convert the fields in struct tm format to the RTC date register fields: * Days: 1-31 match in both cases. * Month: STM32 is 1-12, struct tm is 0-11. * Years: STM32 is 00-99, struct tm is years since 1900. * * Issue: I am not sure what the STM32 years mean. Are these the * years 2000-2099? I'll assume so. */ dr = (rtc_bin2bcd(newtime.tm_mday) << RTC_DR_DU_SHIFT) | ((rtc_bin2bcd(newtime.tm_mon + 1)) << RTC_DR_MU_SHIFT) | ((rtc_bin2bcd(newtime.tm_year - 100)) << RTC_DR_YU_SHIFT); dr &= ~RTC_DR_RESERVED_BITS; /* Disable the write protection for RTC registers */ rtc_wprunlock(); /* Set Initialization mode */ ret = rtc_enterinit(); if (ret == OK) { /* Set the RTC TR and DR registers */ putreg32(tr, STM32_RTC_TR); putreg32(dr, STM32_RTC_DR); /* Exit Initialization mode and wait for the RTC Time and Date * registers to be synchronized with RTC APB clock. */ rtc_exitinit(); ret = rtc_synchwait(); } /* Re-enable the write protection for RTC registers */ rtc_wprlock(); rtc_dumpregs("New time setting"); return ret; } /************************************************************************************ * Name: up_rtc_setalarm * * Description: * Set up an alarm. Up to two alarms can be supported (ALARM A and ALARM B). * * Input Parameters: * tp - the time to set the alarm * callback - the function to call when the alarm expires. * * Returned Value: * Zero (OK) on success; a negated errno on failure * ************************************************************************************/ #ifdef CONFIG_RTC_ALARM int up_rtc_setalarm(FAR const struct timespec *tp, alarmcb_t callback); { irqstate_t flags; int ret = -EBUSY; /* Is there already something waiting on the ALARM? */ if (g_alarmcb == NULL) { /* No.. Save the callback function pointer */ g_alarmcb = callback; /* Break out the time values */ #warning "Missing logic" /* The set the alarm */ #warning "Missing logic" ret = OK; } return ret; } #endif #endif /* CONFIG_RTC */