/************************************************************************************
* arch/arm/src/stm32/stm32f10xxx_rtc.c
*
* Copyright (C) 2011 Uros Platise. All rights reserved.
* Author: Uros Platise <uros.platise@isotel.eu>
*
* With extensions, modifications by:
*
* Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
* Author: Gregroy Nutt <gnutt@nuttx.org>
*
* 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.
*
************************************************************************************/
/* The STM32 RTC Driver offers standard precision of 1 Hz or High Resolution
* operating at rate up to 16384 Hz. It provides UTC time and alarm interface
* with external output pin (for wake-up).
*
* RTC is based on hardware RTC module which is located in a separate power
* domain. The 32-bit counter is extended by 16-bit registers in BKP domain
* STM32_BKP_DR1 to provide system equiv. function to the: time_t time(time_t *).
*
* Notation:
* - clock refers to 32-bit hardware counter
* - time is a combination of clock and upper bits stored in backuped domain
* with unit of 1 [s]
*
* TODO: Error Handling in case LSE fails during start-up or during operation.
*/
/************************************************************************************
* Included Files
************************************************************************************/
#include <nuttx/config.h>
#include <nuttx/arch.h>
#include <nuttx/irq.h>
#include <nuttx/rtc.h>
#include <arch/board/board.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <errno.h>
#include "up_arch.h"
#include "stm32_pwr.h"
#include "stm32_rcc.h"
#include "stm32_rtc.h"
#include "stm32_waste.h"
/************************************************************************************
* Pre-processor Definitions
************************************************************************************/
/* Configuration ********************************************************************/
/* In hi-res mode, the RTC operates at 16384Hz. Overflow interrupts are handled
* when the 32-bit RTC counter overflows every 3 days and 43 minutes. A BKP register
* is incremented on each overflow interrupt creating, effectively, a 48-bit RTC
* counter.
*
* In the lo-res mode, the RTC operates at 1Hz. Overflow interrupts are not handled
* (because the next overflow is not expected until the year 2106.
*
* WARNING: Overflow interrupts are lost whenever the STM32 is powered down. The
* overflow interrupt may be lost even if the STM32 is powered down only momentarily.
* Therefor hi-res solution is only useful in systems where the power is always on.
*/
#ifdef CONFIG_RTC_HIRES
# ifndef CONFIG_RTC_FREQUENCY
# error "CONFIG_RTC_FREQUENCY is required for CONFIG_RTC_HIRES"
# elif CONFIG_RTC_FREQUENCY != 16384
# error "Only hi-res CONFIG_RTC_FREQUENCY of 16384Hz is supported"
# endif
#else
# ifndef CONFIG_RTC_FREQUENCY
# define CONFIG_RTC_FREQUENCY 1
# endif
# if CONFIG_RTC_FREQUENCY != 1
# error "Only lo-res CONFIG_RTC_FREQUENCY of 1Hz is supported"
# endif
#endif
#ifndef CONFIG_STM32_BKP
# error "CONFIG_STM32_BKP is required for CONFIG_RTC"
#endif
/* RTC/BKP Definitions *************************************************************/
/* STM32_RTC_PRESCALAR_VALUE
* RTC pre-scalar value. The RTC is driven by a 32,768Hz input clock. This input
* value is divided by this value (plus one) to generate the RTC frequency.
* RTC_TIMEMSB_REG
* The BKP module register used to hold the RTC overflow value. Overflows are
* only handled in hi-res mode.
* RTC_CLOCKS_SHIFT
* The shift used to convert the hi-res timer LSB to one second. Not used with
* the lo-res timer.
*/
#ifdef CONFIG_RTC_HIRES
# define STM32_RTC_PRESCALAR_VALUE STM32_RTC_PRESCALER_MIN
# define RTC_TIMEMSB_REG STM32_BKP_DR1
# define RTC_CLOCKS_SHIFT 14
#else
# define STM32_RTC_PRESCALAR_VALUE STM32_RTC_PRESCALER_SECOND
#endif
/************************************************************************************
* Private Types
************************************************************************************/
struct rtc_regvals_s
{
uint16_t cntl;
uint16_t cnth;
#ifdef CONFIG_RTC_HIRES
uint16_t ovf;
#endif
};
/************************************************************************************
* Private Data
************************************************************************************/
/* Callback to use when the alarm expires */
#ifdef CONFIG_RTC_ALARM
static alarmcb_t g_alarmcb;
#endif
/************************************************************************************
* Public Data
************************************************************************************/
/* Variable determines the state of the LSE oscilator.
* Possible errors:
* - on start-up
* - during operation, reported by LSE interrupt
*/
volatile bool g_rtc_enabled = false;
/************************************************************************************
* Private Functions
************************************************************************************/
/************************************************************************************
* Name: stm32_rtc_beginwr
*
* Description:
* Enter configuration mode
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
************************************************************************************/
static inline void stm32_rtc_beginwr(void)
{
/* Previous write is done? */
while ((getreg16(STM32_RTC_CRL) & RTC_CRL_RTOFF) == 0)
{
up_waste();
}
/* Enter Config mode, Set Value and Exit */
modifyreg16(STM32_RTC_CRL, 0, RTC_CRL_CNF);
}
/************************************************************************************
* Name: stm32_rtc_endwr
*
* Description:
* Exit configuration mode
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
************************************************************************************/
static inline void stm32_rtc_endwr(void)
{
modifyreg16(STM32_RTC_CRL, RTC_CRL_CNF, 0);
}
/************************************************************************************
* Name: stm32_rtc_wait4rsf
*
* Description:
* Wait for registers to synchronise with RTC module, call after power-up only
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
************************************************************************************/
static inline void stm32_rtc_wait4rsf(void)
{
modifyreg16(STM32_RTC_CRL, RTC_CRL_RSF, 0);
while ((getreg16(STM32_RTC_CRL) & RTC_CRL_RSF) == 0)
{
up_waste();
}
}
/************************************************************************************
* Name: up_rtc_breakout
*
* Description:
* Set the RTC to the provided time.
*
* Input Parameters:
* tp - the time to use
*
* Returned Value:
* None
*
************************************************************************************/
#ifdef CONFIG_RTC_HIRES
static void up_rtc_breakout(FAR const struct timespec *tp,
FAR struct rtc_regvals_s *regvals)
{
uint64_t frac;
uint32_t cnt;
uint16_t ovf;
/* Break up the time in seconds + milleconds into the correct values for our use */
frac = ((uint64_t)tp->tv_nsec * CONFIG_RTC_FREQUENCY) / 1000000000;
cnt = (tp->tv_sec << RTC_CLOCKS_SHIFT) | ((uint32_t)frac & (CONFIG_RTC_FREQUENCY-1));
ovf = (tp->tv_sec >> (32 - RTC_CLOCKS_SHIFT));
/* Then return the broken out time */
regvals->cnth = cnt >> 16;
regvals->cntl = cnt & 0xffff;
regvals->ovf = ovf;
}
#else
static inline void up_rtc_breakout(FAR const struct timespec *tp,
FAR struct rtc_regvals_s *regvals)
{
/* The low-res timer is easy... tv_sec holds exactly the value needed by the
* CNTH/CNTL registers.
*/
regvals->cnth = (uint16_t)((uint32_t)tp->tv_sec >> 16);
regvals->cntl = (uint16_t)((uint32_t)tp->tv_sec & 0xffff);
}
#endif
/************************************************************************************
* Name: stm32_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 defined(CONFIG_RTC_HIRES) || defined(CONFIG_RTC_ALARM)
static int stm32_rtc_interrupt(int irq, void *context)
{
uint16_t source = getreg16(STM32_RTC_CRL);
#ifdef CONFIG_RTC_HIRES
if ((source & RTC_CRL_OWF) != 0)
{
putreg16(getreg16(RTC_TIMEMSB_REG) + 1, RTC_TIMEMSB_REG);
}
#endif
#ifdef CONFIG_RTC_ALARM
if ((source & RTC_CRL_ALRF) != 0 && g_alarmcb != NULL)
{
/* Alarm callback */
g_alarmcb();
g_alarmcb = NULL;
}
#endif
/* Clear pending flags, leave RSF high */
putreg16(RTC_CRL_RSF, STM32_RTC_CRL);
return 0;
}
#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)
{
/* Set access to the peripheral, enable the backup domain (BKP) and the lower power
* extern 32,768Hz (Low-Speed External, LSE) oscillator. Configure the LSE to
* drive the RTC.
*/
stm32_pwr_enablebkp();
stm32_rcc_enablelse();
/* TODO: Get state from this function, if everything is
* okay and whether it is already enabled (if it was disabled
* reset upper time register)
*/
g_rtc_enabled = true;
/* TODO: Possible stall? should we set the timeout period? and return with -1 */
stm32_rtc_wait4rsf();
/* Configure prescaler, note that these are write-only registers */
stm32_rtc_beginwr();
putreg16(STM32_RTC_PRESCALAR_VALUE >> 16, STM32_RTC_PRLH);
putreg16(STM32_RTC_PRESCALAR_VALUE & 0xffff, STM32_RTC_PRLL);
stm32_rtc_endwr();
/* Configure RTC interrupt to catch overflow and alarm interrupts. */
#if defined(CONFIG_RTC_HIRES) || defined(CONFIG_RTC_ALARM)
irq_attach(STM32_IRQ_RTC, stm32_rtc_interrupt);
up_enable_irq(STM32_IRQ_RTC);
#endif
/* Previous write is done? This is required prior writing into CRH */
while ((getreg16(STM32_RTC_CRL) & RTC_CRL_RTOFF) == 0)
{
up_waste();
}
modifyreg16(STM32_RTC_CRH, 0, RTC_CRH_OWIE);
/* Alarm Int via EXTI Line */
/* STM32_IRQ_RTCALRM 41: RTC alarm through EXTI line interrupt */
return OK;
}
/************************************************************************************
* Name: up_rtc_time
*
* Description:
* Get the current time in seconds. This is similar to the standard time()
* function. This interface is only required if the low-resolution RTC/counter
* hardware implementation selected. It is only used by the RTOS during
* intialization to set up the system time when CONFIG_RTC is set but neither
* CONFIG_RTC_HIRES nor CONFIG_RTC_DATETIME are set.
*
* Input Parameters:
* None
*
* Returned Value:
* The current time in seconds
*
************************************************************************************/
#ifndef CONFIG_RTC_HIRES
time_t up_rtc_time(void)
{
irqstate_t flags;
uint16_t cnth;
uint16_t cntl;
uint16_t tmp;
/* The RTC counter is read from two 16-bit registers to form one 32-bit
* value. Because these are non-atomic operations, many things can happen
* between the two reads: This thread could get suspended or interrrupted
* or the lower 16-bit counter could rollover between reads. Disabling
* interrupts will prevent suspensions and interruptions:
*/
flags = irqsave();
/* And the following loop will handle any clock rollover events that may
* happen between samples. Most of the time (like 99.9%), the following
* loop will execute only once. In the rare rollover case, it should
* execute no more than 2 times.
*/
do
{
tmp = getreg16(STM32_RTC_CNTL);
cnth = getreg16(STM32_RTC_CNTH);
cntl = getreg16(STM32_RTC_CNTL);
}
/* The second sample of CNTL could be less than the first sample of CNTL
* only if rollover occurred. In that case, CNTH may or may not be out
* of sync. The best thing to do is try again until we know that no
* rollover occurred.
*/
while (cntl < tmp);
irqrestore(flags);
/* Okay.. the samples should be as close together in time as possible and
* we can be assured that no clock rollover occurred between the samples.
*
* Return the time in seconds.
*/
return (time_t)cnth << 16 | (time_t)cntl;
}
#endif
/************************************************************************************
* Name: up_rtc_gettime
*
* Description:
* Get the current time from the high resolution RTC clock/counter. This interface
* is only supported by the high-resolution RTC/counter hardware implementation.
* It is used to replace the system timer.
*
* Input Parameters:
* tp - The location to return the high resolution time value.
*
* Returned Value:
* Zero (OK) on success; a negated errno on failure
*
************************************************************************************/
#ifdef CONFIG_RTC_HIRES
int up_rtc_gettime(FAR struct timespec *tp)
{
irqstate_t flags;
uint32_t ls;
uint32_t ms;
uint16_t ovf;
uint16_t cnth;
uint16_t cntl;
uint16_t tmp;
/* The RTC counter is read from two 16-bit registers to form one 32-bit
* value. Because these are non-atomic operations, many things can happen
* between the two reads: This thread could get suspended or interrrupted
* or the lower 16-bit counter could rollover between reads. Disabling
* interrupts will prevent suspensions and interruptions:
*/
flags = irqsave();
/* And the following loop will handle any clock rollover events that may
* happen between samples. Most of the time (like 99.9%), the following
* loop will execute only once. In the rare rollover case, it should
* execute no more than 2 times.
*/
do
{
tmp = getreg16(STM32_RTC_CNTL);
cnth = getreg16(STM32_RTC_CNTH);
ovf = getreg16(RTC_TIMEMSB_REG);
cntl = getreg16(STM32_RTC_CNTL);
}
/* The second sample of CNTL could be less than the first sample of CNTL
* only if rollover occurred. In that case, CNTH may or may not be out
* of sync. The best thing to do is try again until we know that no
* rollover occurred.
*/
while (cntl < tmp);
irqrestore(flags);
/* Okay.. the samples should be as close together in time as possible and
* we can be assured that no clock rollover occurred between the samples.
*
* Create a 32-bit value from the LS and MS 16-bit RTC counter values and
* from the MS and overflow 16-bit counter values.
*/
ls = (uint32_t)cnth << 16 | (uint32_t)cntl;
ms = (uint32_t)ovf << 16 | (uint32_t)cnth;
/* Then we can save the time in seconds and fractional seconds. */
tp->tv_sec = (ms << (32-RTC_CLOCKS_SHIFT-16)) | (ls >> (RTC_CLOCKS_SHIFT+16));
tp->tv_nsec = (ls & (CONFIG_RTC_FREQUENCY-1)) * (1000000000/CONFIG_RTC_FREQUENCY);
return OK;
}
#endif
/************************************************************************************
* 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)
{
struct rtc_regvals_s regvals;
irqstate_t flags;
/* Break out the time values */
up_rtc_breakout(tp, ®vals);
/* Then write the broken out values to the RTC counter and BKP overflow register
* (hi-res mode only)
*/
flags = irqsave();
stm32_rtc_beginwr();
putreg16(regvals.cnth, STM32_RTC_CNTH);
putreg16(regvals.cntl, STM32_RTC_CNTL);
stm32_rtc_endwr();
#ifdef CONFIG_RTC_HIRES
putreg16(regvals.ovf, RTC_TIMEMSB_REG);
#endif
irqrestore(flags);
return OK;
}
/************************************************************************************
* Name: up_rtc_setalarm
*
* Description:
* Set up an alarm.
*
* 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)
{
struct rtc_regvals_s regvals;
irqstate_t flags;
uint16_t cr;
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 */
up_rtc_breakout(tp, ®vals);
/* Enable RTC alarm */
cr = getreg16(STM32_RTC_CRH);
cr |= RTC_CRH_ALRIE;
putreg16(cr, STM32_RTC_CRH);
/* The set the alarm */
flags = irqsave();
stm32_rtc_beginwr();
putreg16(regvals.cnth, STM32_RTC_ALRH);
putreg16(regvals.cntl, STM32_RTC_ALRL);
stm32_rtc_endwr();
irqrestore(flags);
ret = OK;
}
return ret;
}
#endif
/************************************************************************************
* Name: up_rtc_cancelalarm
*
* Description:
* Cancel a pending alarm alarm
*
* Input Parameters:
* none
*
* Returned Value:
* Zero (OK) on success; a negated errno on failure
*
************************************************************************************/
#ifdef CONFIG_RTC_ALARM
int up_rtc_cancelalarm(void)
{
irqstate_t flags;
int ret = -ENODATA;
if (g_alarmcb != NULL)
{
/* Cancel the global callback function */
g_alarmcb = NULL;
/* Unset the alarm */
flags = irqsave();
stm32_rtc_beginwr();
putreg16(0xffff, STM32_RTC_ALRH);
putreg16(0xffff, STM32_RTC_ALRL);
stm32_rtc_endwr();
irqrestore(flags);
ret = OK;
}
return ret;
}
#endif
