/**************************************************************************** * arch/arm/src/stm32/stm32_iwdg.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 "up_arch.h" #include "stm32_rcc.h" #include "chip/stm32_dbgmcu.h" #include "stm32_wdg.h" #if defined(CONFIG_WATCHDOG) && defined(CONFIG_STM32_IWDG) /**************************************************************************** * Pre-Processor Definitions ****************************************************************************/ /* Clocking *****************************************************************/ /* The minimum frequency of the IWDG clock is: * * Fmin = Flsi / 256 * * So the maximum delay (in milliseconds) is then: * * 1000 * IWDG_RLR_MAX / Fmin * * For example, if Flsi = 30Khz (the nominal, uncalibrathed value), then the * maximum delay is: * * Fmin = 117.1875 * 1000 * 4095 / Fmin = 34,944 MSec */ #define IWDG_FMIN (STM32_LSI_FREQUENCY / 256) #define IWDG_MAXTIMEOUT (1000 * IWDG_RLR_MAX / IWDG_FMIN) /* Configuration ************************************************************/ #ifndef CONFIG_STM32_IWDG_DEFTIMOUT # define CONFIG_STM32_IWDG_DEFTIMOUT IWDG_MAXTIMEOUT #endif /* REVISIT: It appears that you can only setup the prescaler and reload * registers once. After that, the SR register's PVU and RVU bits never go * to zero. So we defer setting up these registers until the watchdog * is started, then refuse any further attempts to change timeout. */ #define CONFIG_STM32_IWDG_ONETIMESETUP 1 /* Debug ********************************************************************/ /* Non-standard debug that may be enabled just for testing the watchdog * driver. NOTE: that only lldbg types are used so that the output is * immediately available. */ #ifdef CONFIG_DEBUG_WATCHDOG # define wddbg lldbg # define wdvdbg llvdbg #else # define wddbg(x...) # define wdvdbg(x...) #endif /**************************************************************************** * Private Types ****************************************************************************/ /* This structure provides the private representation of the "lower-half" * driver state structure. This structure must be cast-compatible with the * well-known watchdog_lowerhalf_s structure. */ struct stm32_lowerhalf_s { FAR const struct watchdog_ops_s *ops; /* Lower half operations */ uint32_t lsifreq; /* The calibrated frequency of the LSI oscillator */ uint32_t timeout; /* The (actual) selected timeout */ bool started; /* true: The watchdog timer has been started */ uint8_t prescaler; /* Clock prescaler value */ uint16_t reload; /* Timer reload value */ }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* Register operations ******************************************************/ #if defined(CONFIG_STM32_IWDG_REGDEBUG) && defined(CONFIG_DEBUG) static uint16_t stm32_getreg(uint32_t addr); static void stm32_putreg(uint16_t val, uint32_t addr); #else # define stm32_getreg(addr) getreg16(addr) # define stm32_putreg(val,addr) putreg16(val,addr) #endif static inline void stm32_setprescaler(FAR struct stm32_lowerhalf_s *priv); /* "Lower half" driver methods **********************************************/ static int stm32_start(FAR struct watchdog_lowerhalf_s *lower); static int stm32_stop(FAR struct watchdog_lowerhalf_s *lower); static int stm32_keepalive(FAR struct watchdog_lowerhalf_s *lower); static int stm32_getstatus(FAR struct watchdog_lowerhalf_s *lower, FAR struct watchdog_status_s *status); static int stm32_settimeout(FAR struct watchdog_lowerhalf_s *lower, uint32_t timeout); /**************************************************************************** * Private Data ****************************************************************************/ /* "Lower half" driver methods */ static const struct watchdog_ops_s g_wdgops = { .start = stm32_start, .stop = stm32_stop, .keepalive = stm32_keepalive, .getstatus = stm32_getstatus, .settimeout = stm32_settimeout, .capture = NULL, .ioctl = NULL, }; /* "Lower half" driver state */ static struct stm32_lowerhalf_s g_wdgdev; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: stm32_getreg * * Description: * Get the contents of an STM32 IWDG register * ****************************************************************************/ #if defined(CONFIG_STM32_IWDG_REGDEBUG) && defined(CONFIG_DEBUG) static uint16_t stm32_getreg(uint32_t addr) { static uint32_t prevaddr = 0; static uint32_t count = 0; static uint16_t preval = 0; /* Read the value from the register */ uint16_t val = getreg16(addr); /* Is this the same value that we read from the same registe last time? Are * we polling the register? If so, suppress some of the output. */ if (addr == prevaddr && val == preval) { if (count == 0xffffffff || ++count > 3) { if (count == 4) { lldbg("...\n"); } return val; } } /* No this is a new address or value */ else { /* Did we print "..." for the previous value? */ if (count > 3) { /* Yes.. then show how many times the value repeated */ lldbg("[repeats %d more times]\n", count-3); } /* Save the new address, value, and count */ prevaddr = addr; preval = val; count = 1; } /* Show the register value read */ lldbg("%08x->%04x\n", addr, val); return val; } #endif /**************************************************************************** * Name: stm32_putreg * * Description: * Set the contents of an STM32 register to a value * ****************************************************************************/ #if defined(CONFIG_STM32_IWDG_REGDEBUG) && defined(CONFIG_DEBUG) static void stm32_putreg(uint16_t val, uint32_t addr) { /* Show the register value being written */ lldbg("%08x<-%04x\n", addr, val); /* Write the value */ putreg16(val, addr); } #endif /**************************************************************************** * Name: stm32_setprescaler * * Description: * Set up the prescaler and reload values. This seems to be something * that can only be done one time. * * Input Parameters: * priv - A pointer the internal representation of the "lower-half" * driver state structure. * timeout - The new timeout value in millisecnds. * * Returned Values: * Zero on success; a negated errno value on failure. * ****************************************************************************/ static inline void stm32_setprescaler(FAR struct stm32_lowerhalf_s *priv) { /* Enable write access to IWDG_PR and IWDG_RLR registers */ stm32_putreg(IWDG_KR_KEY_ENABLE, STM32_IWDG_KR); /* Wait for the PVU anrd RVU bit to be reset be hardware. These bits * were set the last time that the PR register was written and may not * yet be cleared. */ #ifndef CONFIG_STM32_IWDG_ONETIMESETUP while ((stm32_getreg(STM32_IWDG_SR) & (IWDG_SR_PVU|IWDG_SR_RVU)) != 0); #endif /* Set the prescaler */ stm32_putreg((uint16_t)priv->prescaler << IWDG_PR_SHIFT, STM32_IWDG_PR); /* Set the reload value */ stm32_putreg((uint16_t)priv->reload, STM32_IWDG_RLR); /* Reload the counter (and disable write access) */ stm32_putreg(IWDG_KR_KEY_RELOAD, STM32_IWDG_KR); } /**************************************************************************** * Name: stm32_start * * Description: * Start the watchdog timer, resetting the time to the current timeout, * * Input Parameters: * lower - A pointer the publicly visible representation of the "lower-half" * driver state structure. * * Returned Values: * Zero on success; a negated errno value on failure. * ****************************************************************************/ static int stm32_start(FAR struct watchdog_lowerhalf_s *lower) { FAR struct stm32_lowerhalf_s *priv = (FAR struct stm32_lowerhalf_s *)lower; wdvdbg("Entry: started=%d\n"); DEBUGASSERT(priv); /* Have we already been started? */ if (!priv->started) { /* REVISIT: It appears that you can only setup the prescaler and reload * registers once. After that, the SR register's PVU and RVU bits never go * to zero. So we defer setting up these registers until the watchdog * is started, then refuse any further attempts to change timeout. */ /* Set up prescaler and reload value for the selected timeout */ #ifdef CONFIG_STM32_IWDG_ONETIMESETUP stm32_setprescaler(priv); #endif /* Enable IWDG (the LSI oscillator will be enabled by hardware). NOTE: * If the "Hardware watchdog" feature is enabled through the device option * bits, the watchdog is automatically enabled at power-on. */ stm32_putreg(IWDG_KR_KEY_START, STM32_IWDG_KR); priv->started = true; } return OK; } /**************************************************************************** * Name: stm32_stop * * Description: * Stop the watchdog timer * * Input Parameters: * lower - A pointer the publicly visible representation of the "lower-half" * driver state structure. * * Returned Values: * Zero on success; a negated errno value on failure. * ****************************************************************************/ static int stm32_stop(FAR struct watchdog_lowerhalf_s *lower) { /* There is no way to disable the IDWG timer once it has been started */ wdvdbg("Entry\n"); return -ENOSYS; } /**************************************************************************** * Name: stm32_keepalive * * Description: * Reset the watchdog timer to the current timeout value, prevent any * imminent watchdog timeouts. This is sometimes referred as "pinging" * the atchdog timer or "petting the dog". * * Input Parameters: * lower - A pointer the publicly visible representation of the "lower-half" * driver state structure. * * Returned Values: * Zero on success; a negated errno value on failure. * ****************************************************************************/ static int stm32_keepalive(FAR struct watchdog_lowerhalf_s *lower) { /* Reload the IWDG timer */ wdvdbg("Entry\n"); stm32_putreg(IWDG_KR_KEY_RELOAD, STM32_IWDG_KR); return OK; } /**************************************************************************** * Name: stm32_getstatus * * Description: * Get the current watchdog timer status * * Input Parameters: * lower - A pointer the publicly visible representation of the "lower-half" * driver state structure. * stawtus - The location to return the watchdog status information. * * Returned Values: * Zero on success; a negated errno value on failure. * ****************************************************************************/ static int stm32_getstatus(FAR struct watchdog_lowerhalf_s *lower, FAR struct watchdog_status_s *status) { FAR struct stm32_lowerhalf_s *priv = (FAR struct stm32_lowerhalf_s *)lower; uint32_t elapsed; uint16_t reload; wdvdbg("Entry\n"); DEBUGASSERT(priv); /* Return the status bit */ status->flags = WDFLAGS_RESET; if (priv->started) { status->flags |= WDFLAGS_ACTIVE; } /* Return the actual timeout is milliseconds */ status->timeout = priv->timeout; /* I am not sure what will be returned when reading from the reload register. * Documentation says that the value from the VDD section should be read * so presume it the decremented value. */ reload = stm32_getreg(STM32_IWDG_RLR); elapsed = priv->reload - reload; status->timeleft = (priv->timeout * elapsed) / priv->reload; wdvdbg("Status :\n"); wdvdbg(" flags : %08x\n", status->flags); wdvdbg(" timeout : %d\n", status->timeout); wdvdbg(" timeleft : %d\n", status->flags); return OK; } /**************************************************************************** * Name: stm32_settimeout * * Description: * Set a new timeout value (and reset the watchdog timer) * * Input Parameters: * lower - A pointer the publicly visible representation of the "lower-half" * driver state structure. * timeout - The new timeout value in millisecnds. * * Returned Values: * Zero on success; a negated errno value on failure. * ****************************************************************************/ static int stm32_settimeout(FAR struct watchdog_lowerhalf_s *lower, uint32_t timeout) { FAR struct stm32_lowerhalf_s *priv = (FAR struct stm32_lowerhalf_s *)lower; uint32_t fiwdg; uint64_t reload; int prescaler; int shift; wdvdbg("Entry: timeout=%d\n", timeout); DEBUGASSERT(priv); /* Can this timeout be represented? */ if (timeout < 1 || timeout > IWDG_MAXTIMEOUT) { wddbg("Cannot represent timeout=%d > %d\n", timeout, IWDG_MAXTIMEOUT); return -ERANGE; } /* REVISIT: It appears that you can only setup the prescaler and reload * registers once. After that, the SR register's PVU and RVU bits never go * to zero. */ #ifdef CONFIG_STM32_IWDG_ONETIMESETUP if (priv->started) { wddbg("Timer is already started\n"); return -EBUSY; } #endif /* Select the smallest prescaler that will result in a reload value that is * less than the maximum. */ for (prescaler = 0; ; prescaler++) { /* PR = 0 -> Divider = 4 = 1 << 2 * PR = 1 -> Divider = 8 = 1 << 3 * PR = 2 -> Divider = 16 = 1 << 4 * PR = 3 -> Divider = 32 = 1 << 5 * PR = 4 -> Divider = 64 = 1 << 6 * PR = 5 -> Divider = 128 = 1 << 7 * PR = 6 -> Divider = 256 = 1 << 8 * PR = n -> Divider = 1 << (n+2) */ shift = prescaler + 2; /* Get the IWDG counter frequency in Hz. For a nominal 32Khz LSI clock, * this is value in the range of 7500 and 125. */ fiwdg = priv->lsifreq >> shift; /* We want: * 1000 * reload / Fiwdg = timeout * Or: * reload = Fiwdg * timeout / 1000 */ reload = (uint64_t)fiwdg * (uint64_t)timeout / 1000; /* If this reload valid is less than the maximum or we are not ready * at the prescaler value, then break out of the loop to use these * settings. */ if (reload <= IWDG_RLR_MAX || prescaler == 6) { /* Note that we explicity break out of the loop rather than using * the 'for' loop termination logic because we do not want the * value of prescaler to be incremented. */ break; } } /* Make sure that the final reload value is within range */ if (reload > IWDG_RLR_MAX) { reload = IWDG_RLR_MAX; } /* Get the actual timeout value in milliseconds. * * We have: * reload = Fiwdg * timeout / 1000 * So we want: * timeout = 1000 * reload / Fiwdg */ priv->timeout = (1000 * (uint32_t)reload) / fiwdg; /* Save setup values for later use */ priv->prescaler = prescaler; priv->reload = reload; /* Write the prescaler and reload values to the IWDG registers. * * REVISIT: It appears that you can only setup the prescaler and reload * registers once. After that, the SR register's PVU and RVU bits never go * to zero. */ #ifndef CONFIG_STM32_IWDG_ONETIMESETUP stm32_setprescaler(priv); #endif wdvdbg("prescaler=%d fiwdg=%d reload=%d timeout=%d\n", prescaler, fiwdg, reload, priv->timeout); return OK; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: stm32_iwdginitialize * * Description: * Initialize the IWDG watchdog time. The watchdog timer is intialized and * registers as 'devpath. The initial state of the watchdog time is * disabled. * * Input Parameters: * devpath - The full path to the watchdog. This should be of the form * /dev/watchdog0 * lsifreq - The calibrated LSI clock frequency * * Returned Values: * None * ****************************************************************************/ void stm32_iwdginitialize(FAR const char *devpath, uint32_t lsifreq) { FAR struct stm32_lowerhalf_s *priv = &g_wdgdev; wdvdbg("Entry: devpath=%s lsifreq=%d\n", devpath, lsifreq); /* NOTE we assume that clocking to the IWDG has already been provided by * the RCC initialization logic. */ /* Initialize the driver state structure. */ priv->ops = &g_wdgops; priv->lsifreq = lsifreq; priv->started = false; /* Make sure that the LSI ocsillator is enabled. NOTE: The LSI oscillator * is enabled here but is not disabled by this file (because this file does * not know the the global usage of the oscillator. Any clock management * logic (say, as part of a power management scheme) needs handle other * LSI controls outside of this file. */ stm32_rcc_enablelsi(); wdvdbg("RCC CSR: %08x\n", getreg32(STM32_RCC_CSR)); /* Select an arbitrary initial timeout value. But don't start the watchdog * yet. NOTE: If the "Hardware watchdog" feature is enabled through the * device option bits, the watchdog is automatically enabled at power-on. */ stm32_settimeout((FAR struct watchdog_lowerhalf_s *)priv, CONFIG_STM32_IWDG_DEFTIMOUT); /* Register the watchdog driver as /dev/watchdog0 */ (void)watchdog_register(devpath, (FAR struct watchdog_lowerhalf_s *)priv); /* When the microcontroller enters debug mode (Cortex™-M4F core halted), * the IWDG counter either continues to work normally or stops, depending * on DBG_WIDG_STOP configuration bit in DBG module. */ #if defined(CONFIG_STM32_JTAG_FULL_ENABLE) || \ defined(CONFIG_STM32_JTAG_NOJNTRST_ENABLE) || \ defined(CONFIG_STM32_JTAG_SW_ENABLE) { uint32_t cr = getreg32(STM32_DBGMCU_CR); cr |= DBGMCU_CR_IWDGSTOP; putreg32(cr, STM32_DBGMCU_CR); } #endif } #endif /* CONFIG_WATCHDOG && CONFIG_STM32_IWDG */