/************************************************************************************
* arch/arm/src/stm32/stm32f40xxx_rtc.c
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
* Author: Gregory 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.
*
************************************************************************************/
/************************************************************************************
* Included Files
************************************************************************************/
#include <nuttx/config.h>
#include <nuttx/arch.h>
#include <nuttx/irq.h>
#include <nuttx/rtc.h>
#include <time.h>
#include <errno.h>
#include <debug.h>
#include <arch/board/board.h>
#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_WKUP, rtc_interrupt);
up_enable_irq(STM32_IRQ_RTC_WKUP);
#endif
g_rtc_enabled = true;
rtc_dumpregs("After Initialization");
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 */
