reflow-oven-control-sw/stm-firmware/safety/safety-controller.c

/* Reflow Oven Controller
*
* Copyright (C) 2020  Mario Hüttel <mario.huettel@gmx.net>
*
* This file is part of the Reflow Oven Controller Project.
*
* The reflow oven controller is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* The Reflow Oven Control Firmware is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the reflow oven controller project.
* If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @addtogroup safety-controller
 * @{
 */

#include <reflow-controller/safety/safety-controller.h>
#include <reflow-controller/safety/safety-config.h>
#include <reflow-controller/safety/watchdog.h>
#include <reflow-controller/safety/safety-adc.h>
#include <reflow-controller/safety/stack-check.h>
#include <reflow-controller/hw-version-detect.h>
#include <helper-macros/helper-macros.h>
#include <stm-periph/crc-unit.h>
#include <reflow-controller/systick.h>
#include <reflow-controller/safety/fault.h>
#include <stm32/stm32f4xx.h>
#include <cmsis/core_cm4.h>
#include <stddef.h>
#include <string.h>
#include <reflow-controller/safety/safety-memory.h>
#include <reflow-controller/oven-driver.h>
#include <helper-macros/helper-macros.h>
#include <stm-periph/rcc-manager.h>
#include <reflow-controller/temp-converter.h>
#include <reflow-controller/adc-meas.h>

/**
 * @brief Macro that checks if a given @ref error_flag is persistent
 */
#define check_flag_persistent(flag) ((flag)->persistence && (flag)->persistence->persistence)

/**
 * @brief Macro that retrieves the flag weight of a given @ref error_flag
 *
 * If no flag weight table is present, the flag is evaluated as SAFETY_FLAG_CONFIG_WEIGHT_PANIC
 */
#define get_flag_weight(flag) ((flag)->weight ? ((flag)->weight->weight) : SAFETY_FLAG_CONFIG_WEIGHT_PANIC)

/**
 * @brief Safety controller internal structure implementing a safety flag weight.
 */
struct safety_weight {
	/** @brief Dummy value. This seeds the CRC */
	uint32_t start_dummy;

	/** @brief The safety flag's weight */
	enum config_weight weight;

	/** @brief The enum value of the flag this weight corresponds to */
	enum safety_flag flag;

	/** @brief the flag, this weight corresponds to */
	volatile struct error_flag *flag_ptr;

	/** @brief Dummy value. This seeds the CRC */
	uint32_t end_dummy;
};

/**
 * @brief Safety controller internal struct implementing a flag persistence entry
 */
struct safety_persistence {
	/** @brief Dummy value. This seeds the CRC */
	uint32_t start_dummy;

	/** @brief Corresponding flag is persistent and cannot be cleared */
	bool persistence;

	/** @brief Corresponding safety flag's enum value */
	enum safety_flag flag;

	/** @brief Corresponding safety error flag */
	volatile struct error_flag *flag_ptr;

	/** @brief Dummy value. This seeds the CRC */
	uint32_t end_dummy;
};

/**
 * @brief Safety controller internal struct implementing an error flag
 */
struct error_flag {
	/** @brief Name of the error flag */
	const char *name;

	/** @brief Enum value of this safety flag */
	enum safety_flag flag;

	/** @brief The flag's state. True is errorneous. */
	bool error_state;

	/** @brief Not the flag's state. This always has to be inverted to @ref error_flag::error_state */
	bool error_state_inv;

	/** @brief Persistence entry of this flag */
	volatile struct safety_persistence *persistence;

	/** @brief Weight entry of this flag */
	volatile struct safety_weight *weight;

	/** @brief Key needed to remove this safety flag. If key == 0, no key is set and
	 *  the flag can be cleared by all code
	 */
	uint32_t key;
};

struct timing_mon {
	const char *name;
	enum timing_monitor monitor;
	enum safety_flag associated_flag;
	uint64_t min_delta;
	uint64_t max_delta;
	uint64_t last;
	uint64_t calculated_delta;
	bool enabled;
};

struct analog_mon {
	const char *name;
	enum analog_value_monitor monitor;
	enum safety_flag associated_flag;
	float min;
	float max;
	float value;
	bool valid;
	uint64_t timestamp;
};

struct overtemp_config {
	uint32_t crc_dummy_seed;
	float overtemp_deg_celsius;
	float overtemp_equiv_resistance;
	uint32_t crc;
};

/**
 * @brief All safety error flags.
 */
static volatile struct error_flag IN_SECTION(.ccm.data) flags[] = {
	ERR_FLAG_ENTRY(ERR_FLAG_MEAS_ADC_OFF),
	ERR_FLAG_ENTRY(ERR_FLAG_MEAS_ADC_WATCHDOG),
	ERR_FLAG_ENTRY(ERR_FLAG_MEAS_ADC_UNSTABLE),
	ERR_FLAG_ENTRY(ERR_FLAG_MEAS_ADC_OVERFLOW),
	ERR_FLAG_ENTRY(ERR_FLAG_TIMING_MEAS_ADC),
	ERR_FLAG_ENTRY(ERR_FLAG_TIMING_PID),
	ERR_FLAG_ENTRY(ERR_FLAG_AMON_UC_TEMP),
	ERR_FLAG_ENTRY(ERR_FLAG_AMON_VREF),
	ERR_FLAG_ENTRY(ERR_FLAG_STACK),
	ERR_FLAG_ENTRY(ERR_FLAG_SAFETY_ADC),
	ERR_FLAG_ENTRY(ERR_FLAG_SYSTICK),
	ERR_FLAG_ENTRY(ERR_FLAG_WTCHDG_FIRED),
	ERR_FLAG_ENTRY(ERR_FLAG_UNCAL),
	ERR_FLAG_ENTRY(ERR_FLAG_DEBUG),
	ERR_FLAG_ENTRY(ERR_FLAG_TIMING_MAIN_LOOP),
	ERR_FLAG_ENTRY(ERR_FLAG_SAFETY_MEM_CORRUPT),
	ERR_FLAG_ENTRY(ERR_FLAG_SAFETY_TAB_CORRUPT),
	ERR_FLAG_ENTRY(ERR_FLAG_AMON_SUPPLY_VOLT),
	ERR_FLAG_ENTRY(ERR_FLAG_OVERTEMP),
};

/**
  * @brief All timing monitors
  */
static volatile struct timing_mon IN_SECTION(.ccm.data) timings[] = {
	TIM_MON_ENTRY(ERR_TIMING_PID, 2, 5000, ERR_FLAG_TIMING_PID),
	TIM_MON_ENTRY(ERR_TIMING_MEAS_ADC, 0, 50, ERR_FLAG_TIMING_MEAS_ADC),
	TIM_MON_ENTRY(ERR_TIMING_SAFETY_ADC, 10, SAFETY_CONTROLLER_ADC_DELAY_MS + 1000, ERR_FLAG_SAFETY_ADC),
	TIM_MON_ENTRY(ERR_TIMING_MAIN_LOOP, 0, 1000, ERR_FLAG_TIMING_MAIN_LOOP),
};

/**
 * @brief All analog value monitors
 */
static volatile struct analog_mon IN_SECTION(.ccm.data) analog_mons[] = {
	ANA_MON_ENTRY(ERR_AMON_VREF, SAFETY_ADC_VREF_MVOLT - SAFETY_ADC_VREF_TOL_MVOLT,
	SAFETY_ADC_VREF_MVOLT + SAFETY_ADC_VREF_TOL_MVOLT, ERR_FLAG_AMON_VREF),
	ANA_MON_ENTRY(ERR_AMON_UC_TEMP, SAFETY_ADC_TEMP_LOW_LIM, SAFETY_ADC_TEMP_HIGH_LIM,
		ERR_FLAG_AMON_UC_TEMP),
	ANA_MON_ENTRY(ERR_AMON_SUPPLY_VOLT, SAFETY_ADC_SUPPLY_MVOLT - SAFETY_ADC_SUPPLY_TOL_MVOLT,
		SAFETY_ADC_SUPPLY_MVOLT + SAFETY_ADC_SUPPLY_TOL_MVOLT,
		ERR_FLAG_AMON_SUPPLY_VOLT),
};

/**
 * @brief The default flag weights, that are loaded on boot.
 */
static const struct safety_weight default_flag_weights[] = { SAFETY_CONFIG_DEFAULT_WEIGHTS };

/**
 * @brief The default flag persistencies, that are loaded on boot.
 */
static const struct safety_persistence default_flag_persistencies[] = {SAFETY_CONFIG_DEFAULT_PERSIST};

/**
 * @brief The working copy of the flag persistence table. It is protected by the @ref flag_persistencies_crc
 * @note This is stored in CCM RAM
 */
static volatile struct safety_persistence IN_SECTION(.ccm.bss) flag_persistencies[COUNT_OF(default_flag_persistencies)];

/**
 * @brief The CRC of the flag weight table @ref flag_persistencies.
 *
 * The CRC is calculated using the internal CRC module of the STM32F407 controller.
 * See the refernece manual for the polynomial.
 *
 * @note This is stored in CCM RAM.
 */
static uint32_t IN_SECTION(.ccm.bss) flag_persistencies_crc;

/**
 * @brief The working copy of the flag weight table. It is protected by the @ref flag_weight_crc.
 * @note This is stored in CCM RAM
 */
static volatile struct safety_weight IN_SECTION(.ccm.bss) flag_weights[COUNT_OF(default_flag_weights)];

/**
 * @brief The CRC of the flag weight table @ref flag_weights.
 *
 * The CRC is calculated using the internal CRC module of the STM32F407 controller.
 * See the refernece manual for the polynomial.
 *
 * @note This is stored in CCM RAM.
 */
static uint32_t IN_SECTION(.ccm.bss) flag_weight_crc;

/**
 * @brief Configuration struct containing the overtemperature flag configuration
 */
static struct overtemp_config IN_SECTION(.ccm.bss) safety_controller_overtemp_config;

/**
 * @brief Configure the overtemperature flag's settings
 * @param over_temperature Temperature to set the limit to.
 */
static void set_overtemp_config(float over_temperature)
{
	int result;
	float resistance;

	result = temp_convertet_convert_temp_to_resistance(over_temperature, &resistance);
	/* An error in this function is really bad... */
	if (result < -1)
		panic_mode();

	crc_unit_reset();
	safety_controller_overtemp_config.crc_dummy_seed = 0xA4F5C7E6UL;
	safety_controller_overtemp_config.overtemp_deg_celsius = over_temperature;
	safety_controller_overtemp_config.overtemp_equiv_resistance = resistance;
	crc_unit_input_array((const uint32_t *)&safety_controller_overtemp_config, wordsize_of(struct overtemp_config) - 1);
	safety_controller_overtemp_config.crc = crc_unit_get_crc();
}

static bool over_temperature_config_check(void)
{
	if (safety_controller_overtemp_config.crc_dummy_seed != 0xA4F5C7E6UL)
		return true;
	crc_unit_reset();
	crc_unit_input_array((const uint32_t *)&safety_controller_overtemp_config, wordsize_of(struct overtemp_config) - 1);
	if (crc_unit_get_crc() != safety_controller_overtemp_config.crc)
		return true;

	return false;
}

/**
 * @brief Convert a flag enum to the flag number.
 *
 * Flag numbers are used by the error memory to store flags.
 * This function will fail and return 0xFF if multiple flags are ORed and
 * passed as flag parameter.
 *
 * @param flag Flag enum
 * @return Flag number or 0xFF in case of an error
 */
static uint8_t flag_enum_to_flag_no(enum safety_flag flag)
{
	uint32_t flag_mask;
	uint8_t i;

	if (!is_power_of_two(flag))
		return 0xFF;

	flag_mask = (uint32_t)flag;
	for (i = 0; i < 32; i++) {
		if ((flag_mask >> i) & 0x1U)
			break;
	}

	return i;
}

/**
 * @brief Convert a safety flag's number to its enum value.
 *
 * Flag numbers are used by the error memory to store flags.
 *
 * @param no The flag number.
 * @return Flag enum
 */
static enum safety_flag flag_no_to_flag_enum(uint8_t no)
{
	if (no >= COUNT_OF(flags))
		return ERR_FLAG_NO_FLAG;

	return (1U << no);
}

/**
 * @brief Check the CRC chacksum of the flag weight table
 * @return 0 if CRC is valid, else -1;
 */
static int flag_weight_table_crc_check(void)
{
	/* Check the flag weight table */
	crc_unit_reset();
	crc_unit_input_array((uint32_t *)flag_weights, wordsize_of(flag_weights));

	if (crc_unit_get_crc() != flag_weight_crc)
		return -1;

	return 0;
}

/**
 * @brief Check the CRC chacksum of the flag persistence table
 * @return 0 if CRC is valid, else -1.
 */
static int flag_persistency_table_crc_check(void)
{
	crc_unit_reset();
	crc_unit_input_array((uint32_t*)flag_persistencies, wordsize_of(flag_persistencies));

	if (crc_unit_get_crc() != flag_persistencies_crc)
		return -1;

	return 0;
}

/**
 * @brief Find the error flag structure for a given safety_flag enum
 *
 *  Only one flag can be given at a time. Giving multiple flags by ORing them
 *  together, will not math any flag at all.
 *
 * @param flag Enum defining the flag.
 * @return NULL in case nothing matched. Pointer otherwise.
 */
static volatile struct error_flag *find_error_flag(enum safety_flag flag)
{
	uint32_t i;
	volatile struct error_flag *ret = NULL;

	for (i = 0; i < COUNT_OF(flags); i++) {
		if (flags[i].flag == flag)
			ret = &flags[i];
	}

	return ret;
}

/**
 * @brief This function copies the safety weigths from flash ro RAM and computes the CRC
 */
static void init_safety_flag_weight_table_from_default(void)
{
	uint32_t index;
	volatile struct safety_weight *current_weight;

	/* Copy the table */
	memcpy((void *)flag_weights, default_flag_weights, sizeof(flag_weights));

	/* Fill in the flag pointers */
	for (index = 0; index < COUNT_OF(flag_weights); index++) {
		current_weight = &flag_weights[index];
		current_weight->flag_ptr = find_error_flag(current_weight->flag);
		if (current_weight->flag_ptr)
			current_weight->flag_ptr->weight = current_weight;
	}

	crc_unit_reset();
	crc_unit_input_array((uint32_t*)flag_weights, wordsize_of(flag_weights));
	flag_weight_crc = crc_unit_get_crc();
}

/**
 * @brief Initialize the default persistence settings of all safety flags.
 *
 * This function copies the default persistence settings of the safety flags defined in
 * @ref SAFETY_CONFIG_DEFAULT_PERSIST and computes the protection CRC over the settings.
 */
static void init_safety_flag_persistencies_from_default(void)
{
	uint32_t index;
	volatile struct safety_persistence *current_persistence;

	/* Copy values */
	memcpy((void *)flag_persistencies, default_flag_persistencies, sizeof(flag_persistencies));

	/* Fill in flag pointers */
	for (index = 0; index < COUNT_OF(flag_persistencies); index++) {
		current_persistence = &flag_persistencies[index];
		current_persistence->flag_ptr = find_error_flag(current_persistence->flag);
		if (current_persistence->flag_ptr)
			current_persistence->flag_ptr->persistence = current_persistence;
	}

	crc_unit_reset();
	crc_unit_input_array((uint32_t *)flag_persistencies, wordsize_of(flag_persistencies));
	flag_persistencies_crc = crc_unit_get_crc();
}

/**
 * @brief Apply the config overrrides stored in the safety memory.
 *
 * The config overrides are read from the safety memory and applied.
 * The config overrides can override the following things:
 *
 * 1) Safety Weights (See @ref config_weight)
 * 2) Flag Persistence
 */
static void apply_config_overrides(void)
{
	uint32_t count;
	uint32_t idx;
	struct config_override override;
	int res;
	enum safety_flag flag_enum;
	volatile struct error_flag *flag;

	res = safety_memory_get_config_override_count(&count);
	if (res)
		return;
	for (idx = 0; idx < count; idx++) {
		res = safety_memory_get_config_override(idx, &override);
		if (res)
			continue;
		switch (override.type) {
		case SAFETY_MEMORY_CONFIG_OVERRIDE_WEIGHT:
			flag_enum = flag_no_to_flag_enum(override.entry.weight_override.flag);
			flag = find_error_flag(flag_enum);
			if (flag && flag->weight) {
				flag->weight->weight = override.entry.weight_override.weight;
			}
			break;
		case SAFETY_MEMORY_CONFIG_OVERRIDE_PERSISTENCE:
			flag_enum = flag_no_to_flag_enum(override.entry.persistance_override.flag);
			flag = find_error_flag(flag_enum);
			if (flag && flag->persistence) {
				flag->persistence->persistence = override.entry.persistance_override.persistance;
			}
			break;
		default:
			continue;
		}
	}

	/* Patch new CRCs */
	crc_unit_reset();
	crc_unit_input_array((uint32_t *)flag_persistencies, wordsize_of(flag_persistencies));
	flag_persistencies_crc = crc_unit_get_crc();
	crc_unit_reset();
	crc_unit_input_array((uint32_t*)flag_weights, wordsize_of(flag_weights));
	flag_weight_crc = crc_unit_get_crc();
}

/**
 * @brief Get the error state of a flag.
 *
 * This function takes inbto account that the error_flag::error_state and
 * error_flag::error_state_inv fileds must never be the same value. In case they are,
 * the flag is treated as errorneous.
 * @param flag Flag to check
 * @return The error state
 */
static bool error_flag_get_status(const volatile struct error_flag *flag)
{
	if (!flag)
		return true;

	if (flag->error_state == flag->error_state_inv) {
		return true;
	} else {
		return flag->error_state;
	}
}

/**
 * @brief Find a analog value monitor structure by its enum number
 * @param mon Enum representing the analog monitor
 * @return NULL incase nothing is found, else pointer to structure.
 */
static volatile struct analog_mon *find_analog_mon(enum analog_value_monitor mon)
{
	uint32_t i;
	volatile struct analog_mon *ret = NULL;

	for (i = 0; i < COUNT_OF(analog_mons); i++) {
		if (analog_mons[i].monitor == mon)
			ret = &analog_mons[i];
	}

	return ret;
}

/**
 * @brief Find a timing monitor structure by its enum number
 * @param mon Enum representing the timing monitor
 * @return NULL incase nothing is found, else pointer to structure.
 */
static volatile struct timing_mon *find_timing_mon(enum timing_monitor mon)
{
	uint32_t i;
	volatile struct timing_mon *ret = NULL;

	for (i = 0; i < COUNT_OF(timings); i++) {
		if (timings[i].monitor == mon)
			ret = &timings[i];
	}

	return ret;
}

/**
 * @brief Check the active timing monitors and set the appropriate flags in case of an error.
 */
static void safety_controller_process_active_timing_mons()
{
	uint32_t i;
	volatile struct timing_mon *current_mon;
	uint64_t last;

	for (i = 0; i < COUNT_OF(timings); i++) {
		current_mon = &timings[i];
		if (current_mon->enabled) {
			__disable_irq();
			last = current_mon->last;
			__enable_irq();
			if (systick_ticks_have_passed(last, current_mon->max_delta))
				safety_controller_report_error(current_mon->associated_flag);
		}
	}
}

/**
 * @brief safety_controller_process_monitor_checks
 * Process the analog and timing monitors and set the relevant flags in case of a monitor outside its limits.
 * Furthermore, the PT1000 resistance is checked for overtemperature
 *
 * The checking of the analog monitors will only be armed after a startup delay of 1000 ms to allow the values to stabilize.
 */
static void safety_controller_process_monitor_checks(void)
{
	static bool startup_completed = false;
	struct analog_monitor_info amon_info;
	uint32_t idx;
	uint32_t analog_mon_count;
	float pt1000_val = 1000000.0f;

	if (!startup_completed && systick_get_global_tick() >= 1000)
		startup_completed = true;

	if (startup_completed) {
		analog_mon_count = safety_controller_get_analog_monitor_count();
		for (idx = 0; idx < analog_mon_count; idx++) {
			if (safety_controller_get_analog_mon_by_index(idx, &amon_info)) {
				panic_mode();
			}

			if (amon_info.status != ANALOG_MONITOR_OK) {
				safety_controller_report_error(amon_info.associated_flag);
			}
		}
	}

	adc_pt1000_get_current_resistance(&pt1000_val);
	if (pt1000_val > safety_controller_overtemp_config.overtemp_equiv_resistance) {
		safety_controller_report_error(ERR_FLAG_OVERTEMP);
	}

	safety_controller_process_active_timing_mons();
}

/**
 * @brief Internal function for setting an error flag
 *
 * Multiple flags can be ored together to set them in one go.
 * The provided key will be set on all of the flags in order to prevent them from being reset by
 * unauthorized code. If nop key shall be used, set key to zero.
 *
 * @param flag Enum of the flags to set. This can be an ORed value of multiple error flags.
 * @param key The kex to set on the flag.
 * @param prevent_error_mem_enty Prevent the flag from being stored in the error memory.
 * @return 0 if successful.
 */
static int report_error(enum safety_flag flag, uint32_t key, bool prevent_error_mem_enty)
{
	uint32_t i;
	int ret = -1;
	bool old_state;
	int res;
	struct error_memory_entry err_mem_entry;

	for (i = 0; i < COUNT_OF(flags); i++) {
		if (flags[i].flag & flag) {
			old_state = flags[i].error_state;
			flags[i].error_state = true;
			flags[i].error_state_inv = !flags[i].error_state;
			flags[i].key = key;

			if ((check_flag_persistent(&flags[i]) && !old_state && !prevent_error_mem_enty) || 
				get_flag_weight(&flags[i]) == SAFETY_FLAG_CONFIG_WEIGHT_PANIC) {
				err_mem_entry.counter = 1;
				err_mem_entry.flag_num = flag_enum_to_flag_no(flags[i].flag);
				err_mem_entry.type = SAFETY_MEMORY_ERR_ENTRY_FLAG;
				res = safety_memory_insert_error_entry(&err_mem_entry);
				if (res)
					ret = -12;
			} else {
				ret = 0;
			}

			flag &= ~flags[i].flag;
			if (!flag)
				break;
		}
	}

	return ret;
}

int safety_controller_report_error(enum safety_flag flag)
{
	return safety_controller_report_error_with_key(flag, 0x0UL);
}

int safety_controller_report_error_with_key(enum safety_flag flag, uint32_t key)
{
	return report_error(flag, key, false);
}

void safety_controller_report_timing(enum timing_monitor monitor)
{
	volatile struct timing_mon *tim;
	uint64_t timestamp;

	timestamp = systick_get_global_tick();

	tim = find_timing_mon(monitor);
	if (tim) {
		if (tim->enabled) {
			if (!systick_ticks_have_passed(tim->last, tim->min_delta) && tim->min_delta > 0U) {
				safety_controller_report_error(tim->associated_flag);
			}
		}

		tim->calculated_delta = timestamp - tim->last;
		tim->last = timestamp;
		tim->enabled = true;
	}

}

void safety_controller_report_analog_value(enum analog_value_monitor monitor, float value)
{
	volatile struct analog_mon *ana;

	/* Return if not a power of two */
	if (!is_power_of_two(monitor))
		return;
	ana = find_analog_mon(monitor);
	if (ana) {
		ana->valid = true;
		ana->value = value;
		ana->timestamp = systick_get_global_tick();
	}

}

/**
 * @brief Return the flags, which are set in the error memory
 * @param flags Flags read from error memory
 * @return 0 if ok, != 0 if error
 */
static int get_safety_flags_from_error_mem(enum safety_flag *flags)
{
	uint32_t count;
	uint32_t idx;
	int res;
	enum safety_flag return_flags = 0;
	struct error_memory_entry entry;

	if (!flags)
		return -1001;

	res = safety_memory_get_error_entry_count(&count);
	if (res)
		return -1;

	for (idx = 0; idx < count; idx++) {
		res = safety_memory_get_error_entry(idx, &entry);
		if (entry.type == SAFETY_MEMORY_ERR_ENTRY_FLAG) {
			return_flags |= flag_no_to_flag_enum(entry.flag_num);
		}
	}

	*flags = return_flags;
	return 0;
}

/**
 * @brief Initialize the GPIOs for the external hardware watchdog.
 *
 * The external harware watchdog has to be periodically reset or it will reset hte controller.
 * Because debugging is not possible, when the watchdog is active, it is only activated, if the application is
 * compiled in release mode. Any interruption of the main programm will then trigger the internal and/or the external watchdog.
 *
 * @note When enabled, execute the @ref external_watchdog_toggle function to reset the external watchdog.
 */
static void safety_controller_init_external_watchdog()
{
	rcc_manager_enable_clock(&RCC->AHB1ENR, BITMASK_TO_BITNO(SAFETY_EXT_WATCHDOG_RCC_MASK));
	SAFETY_EXT_WATCHDOG_PORT->MODER &= MODER_DELETE(SAFETY_EXT_WATCHDOG_PIN);
#ifndef DEBUGBUILD
	SAFETY_EXT_WATCHDOG_PORT->MODER |= OUTPUT(SAFETY_EXT_WATCHDOG_PIN);
	SAFETY_EXT_WATCHDOG_PORT->ODR |= (1<<SAFETY_EXT_WATCHDOG_PIN);
#endif
	__DSB();
}

void safety_controller_init()
{
	enum safety_memory_state found_memory_state;
	enum safety_flag flags_in_err_mem = ERR_FLAG_NO_FLAG;
	enum hw_revision hw_rev;

	int res;

	/* Init the safety memory */
	if (safety_memory_init(&found_memory_state)) {
		/* Trigger panic mode! */
		panic_mode();
	}

	/* This is usually done by the safety memory already. But, since this module also uses the CRC... */
	crc_unit_init();

	stack_check_init_corruption_detect_area();

	hw_rev = get_pcb_hardware_version();
	if (hw_rev == HW_REV_ERROR)
		panic_mode();
	if (hw_rev != HW_REV_V1_2)
		safety_controller_init_external_watchdog();

	init_safety_flag_weight_table_from_default();
	init_safety_flag_persistencies_from_default();
	apply_config_overrides();

	/* Set the default limit of the overtemperature check */
	set_overtemp_config(SAFETY_DEFAULT_OVERTEMP_LIMIT_DEGC);

	if (found_memory_state == SAFETY_MEMORY_INIT_CORRUPTED)
		safety_controller_report_error(ERR_FLAG_SAFETY_MEM_CORRUPT);
	else if (found_memory_state == SAFETY_MEMORY_INIT_VALID_MEMORY) {
		/* restore the corrupt flag flag */
		res = get_safety_flags_from_error_mem(&flags_in_err_mem);
		if (res)
			panic_mode();
		if (flags_in_err_mem & ERR_FLAG_SAFETY_MEM_CORRUPT)
			report_error(ERR_FLAG_SAFETY_MEM_CORRUPT, 0, true);
	}

	/* Init default flag states */
	safety_controller_report_error_with_key(ERR_FLAG_MEAS_ADC_OFF | ERR_FLAG_MEAS_ADC_UNSTABLE,
						MEAS_ADC_SAFETY_FLAG_KEY);

	safety_adc_init();
	watchdog_setup(WATCHDOG_PRESCALER);

	if (rcc_manager_get_reset_cause(false) & RCC_RESET_SOURCE_IWDG)
		safety_controller_report_error(ERR_FLAG_WTCHDG_FIRED);

#ifdef DEBUGBUILD
	safety_controller_report_error(ERR_FLAG_DEBUG);
#endif
}

/**
 * @brief Check the processor's stack
 *
 * This function checks the Stack of the application.
 * The check consists of 2 parts:
 *
 * 1) Checking the remaining free space at the moment between stack pointer and top of heap.
 * 2) Checking The CRC of the corruption detect area between heap and stack
 */
static void safety_controller_check_stack()
{
	int32_t free_stack;

	free_stack = stack_check_get_free();
	if (free_stack < SAFETY_MIN_STACK_FREE)
		safety_controller_report_error(ERR_FLAG_STACK);

	if (stack_check_corruption_detect_area()) {
		safety_controller_report_error(ERR_FLAG_STACK);
	}
}

/**
 * @brief Handle the Safety ADC
 *
 * This function handles the safety ADC.
 * If the safety ADC ius not executing a measurment and the time since the last measurement has
 * passed @ref SAFETY_CONTROLLER_ADC_DELAY_MS, the safety ADC is retriggered and will automatically perform a measurement
 * on all of its channels.
 * When called again, this function will retrieve the data from the safety ADC and  converts it into the
 * appropriate analog values for the analog value monitors.
 *
 * The safety ADC is configured to perform multiple measurmeents of each physical channel. Therefore, this function
 * fist calculated the mean value before converting them into the physical values.
 *
 * The channels, the ssafety ADC will convert is defined in its header file using the define @ref SAFETY_ADC_CHANNELS.
 */
static void safety_controller_handle_safety_adc()
{
	static uint64_t last_result_timestamp = 0;
	const uint16_t *channels;
	uint32_t sum;
	int poll_result;
	float analog_value;

	poll_result = safety_adc_poll_result();

	if (poll_result == 1) {
		/* Data available */
		channels = safety_adc_get_values();

		/* Compute average of temp readings */
		sum = channels[0] + channels[1] + channels[2] + channels[3];
		sum /= 4;

		analog_value = safety_adc_convert_channel(SAFETY_ADC_MEAS_TEMP, (uint16_t)sum);
		safety_controller_report_analog_value(ERR_AMON_UC_TEMP, analog_value);

		/* Average VREF readings */
		sum = channels[4] + channels[5] + channels[6] + channels[7];
		sum /= 4;

		analog_value = safety_adc_convert_channel(SAFETY_ADC_MEAS_VREF, (uint16_t)sum);
		safety_controller_report_analog_value(ERR_AMON_VREF, analog_value);

		/* Compute supply voltage reading */
		sum = channels[8] + channels[9] + channels[10] + channels[11];
		sum /= 4;
		analog_value = safety_adc_convert_channel(SAFETY_ADC_MEAS_SUPPLY, (uint16_t)sum);

		safety_controller_report_analog_value(ERR_AMON_SUPPLY_VOLT, analog_value);

		last_result_timestamp = systick_get_global_tick();
		safety_controller_report_timing(ERR_TIMING_SAFETY_ADC);
	}

	if (systick_ticks_have_passed(last_result_timestamp, SAFETY_CONTROLLER_ADC_DELAY_MS)) {
		if (poll_result != 1 && poll_result != 0)
			safety_adc_trigger_meas();
	}

}

/**
 * @brief Check the memory structures
 *
 * This function checks multiple memory structures.
 *
 * 1) The safety memory in the backup RAM is checked using @ref safety_memory_check.
 *    In case of an error, the safety memory is reinitialized and the @ref ERR_FLAG_SAFETY_MEM_CORRUPT
 *    flag is set.
 * 2) The flag weight table is CRC checked. In case of an error, the @ref ERR_FLAG_SAFETY_TAB_CORRUPT flag is set.
 *    Aditionally, the default flag weights are restored from Flash.
 * 3) The flag persistency table is CRC checked. In case of an error, the @ref ERR_FLAG_SAFETY_TAB_CORRUPT flag is set.
 *    Aditionally, the default values of the flag persistence is restored from Flash.
 * 4) Check the Overtemperature flag configuration structure
 */
static void safety_controller_handle_memory_checks(void)
{
	static uint64_t ts = 0;
	enum safety_memory_state found_state;

	if (systick_ticks_have_passed(ts, 250)) {
		ts = systick_get_global_tick();

		/* Check the safety memory */
		if (safety_memory_check()) {
			(void)safety_memory_reinit(&found_state);
			if (found_state != SAFETY_MEMORY_INIT_VALID_MEMORY) {
				safety_controller_report_error(ERR_FLAG_SAFETY_MEM_CORRUPT);
			}
		}

		/* If flag weight table is broken, reinit to default and set flag */
		if (flag_weight_table_crc_check()) {
			safety_controller_report_error(ERR_FLAG_SAFETY_TAB_CORRUPT);
			init_safety_flag_weight_table_from_default();
		}

		/* If persistency table is broken, reinit to default and set flag */
		if(flag_persistency_table_crc_check()) {
			safety_controller_report_error(ERR_FLAG_SAFETY_TAB_CORRUPT);
			init_safety_flag_persistencies_from_default();
		}

		/* check overtemp struct */
		if (over_temperature_config_check()) {
			safety_controller_report_error(ERR_FLAG_SAFETY_TAB_CORRUPT);
			set_overtemp_config(SAFETY_DEFAULT_OVERTEMP_LIMIT_DEGC);
		}
	}
}

/**
 * @brief Check if the systick is ticking.
 *
 * If the systick stays constant for more than 1000 calls of this function,
 * the @ref ERR_FLAG_SYSTICK flag is set.
 */
static void safety_controller_do_systick_checking()
{
	static uint64_t last_systick;
	static uint32_t same_systick_cnt = 0UL;
	uint64_t systick;

	systick = systick_get_global_tick();
	if (systick == last_systick) {
		same_systick_cnt++;
		if (same_systick_cnt > 1000)
			safety_controller_report_error(ERR_FLAG_SYSTICK);
	} else {
		same_systick_cnt = 0UL;
	}
	last_systick = systick;
}

/**
 * @brief Handle weightet flags.
 *
 * This functions loops over all error flags and checks the weights. If a flag
 * is set, the appropriate action defined by the flag weight is executed.
 * @note If no flag weigth is present for a given error flag, it is treated as the most critical category
 * (@ref SAFETY_FLAG_CONFIG_WEIGHT_PANIC)
 */
static void safety_controller_handle_weighted_flags()
{
	uint32_t flag_index;
	volatile struct error_flag *current_flag;
	enum config_weight flag_weigth;

	for (flag_index = 0u; flag_index < COUNT_OF(flags); flag_index++) {
		current_flag = &flags[flag_index];

		/* Continue if this flag is not set */
		if (!error_flag_get_status(current_flag)) {
			continue;
		}

		flag_weigth = get_flag_weight(current_flag);
		switch (flag_weigth) {
		case SAFETY_FLAG_CONFIG_WEIGHT_NONE:
			break;
		case SAFETY_FLAG_CONFIG_WEIGHT_PID:
			oven_pid_abort();
			break;
		case SAFETY_FLAG_CONFIG_WEIGHT_PANIC:
			/* EXPECTED FALLTHRU */
		default:
			oven_pid_abort();
			panic_mode();
			break;
		}

	}
}

#ifndef DEBUGBUILD
static void external_watchdog_toggle()
{
	SAFETY_EXT_WATCHDOG_PORT->ODR ^= (1<<SAFETY_EXT_WATCHDOG_PIN);
}
#endif

int safety_controller_handle()
{
	int ret = 0;
#ifndef DEBUGBUILD
	static uint32_t watchdog_counter = 0UL;
#endif

	safety_controller_check_stack();
	safety_controller_handle_safety_adc();
	safety_controller_handle_memory_checks();
	safety_controller_do_systick_checking();
	safety_controller_process_monitor_checks();
	safety_controller_handle_weighted_flags();

	ret |= watchdog_ack(WATCHDOG_MAGIC_KEY);

#ifndef DEBUGBUILD
	if (get_pcb_hardware_version() != HW_REV_V1_2) {
		watchdog_counter++;
		if (watchdog_counter > 30) {
			external_watchdog_toggle();
			watchdog_counter = 0UL;
		}
	}
#endif
	return (ret ? -1 : 0);
}

int safety_controller_enable_timing_mon(enum timing_monitor monitor, bool enable)
{
	volatile struct timing_mon *tim;

	if (enable) {
		safety_controller_report_timing(monitor);
	} else {
		tim = find_timing_mon(monitor);
		if (!tim)
			return -1;
		tim->enabled = false;
	}

	return 0;
}

enum analog_monitor_status safety_controller_get_analog_mon_value(enum analog_value_monitor monitor, float *value)
{
	volatile struct analog_mon *mon;
	int ret = ANALOG_MONITOR_ERROR;

	if (!is_power_of_two(monitor))
		goto go_out;

	if (!value)
		goto go_out;

	mon = find_analog_mon(monitor);
	if (mon) {
		if (!mon->valid) {
			ret = ANALOG_MONITOR_INACTIVE;
			goto go_out;
		}

		*value = mon->value;
		if (mon->value < mon->min)
			ret = ANALOG_MONITOR_UNDER;
		else if (mon->value > mon->max)
			ret = ANALOG_MONITOR_OVER;
		else
			ret = ANALOG_MONITOR_OK;
	}

go_out:
	return ret;
}

int safety_controller_get_flag(enum safety_flag flag, bool *status, bool try_ack)
{
	volatile struct error_flag *found_flag;
	int ret = -1;

	if (!status)
		return -1002;
	if (!is_power_of_two(flag))
		return -1001;

	found_flag = find_error_flag(flag);
	if (found_flag) {
		*status = error_flag_get_status(found_flag);
		if (try_ack && !check_flag_persistent(found_flag)) {
			/* Flag is generally non persistent
			 * If key is set, this function cannot remove the flag
			 */
			if (found_flag->key == 0UL) {
				found_flag->error_state = false;
				found_flag->error_state_inv = !found_flag->error_state;
			}
		}
	}

	return ret;
}

int safety_controller_ack_flag(enum safety_flag flag)
{
	return safety_controller_ack_flag_with_key(flag, 0UL);
}

int safety_controller_ack_flag_with_key(enum safety_flag flag, uint32_t key)
{
	int ret = -1;
	volatile struct error_flag *found_flag;

	if (!is_power_of_two(flag)) {
		return -1001;
	}

	found_flag = find_error_flag(flag);
	if (found_flag) {
		if (!check_flag_persistent(found_flag) && (found_flag->key == key || !found_flag->key)) {
			found_flag->error_state = false;
			found_flag->error_state_inv = true;
			ret = 0;
		} else {
			ret = -2;
		}
	}

	return ret;
}

bool safety_controller_get_flags_by_mask(enum safety_flag mask)
{
	uint32_t i;
	bool ret = false;

	for (i = 0; i < COUNT_OF(flags); i++) {
		if ((flags[i].flag & mask) && error_flag_get_status(&flags[i])) {
			ret = true;
			break;
		}
	}

	return ret;
}

uint32_t safety_controller_get_flag_count()
{
	return COUNT_OF(flags);
}

uint32_t safety_controller_get_analog_monitor_count()
{
	return COUNT_OF(analog_mons);
}

uint32_t safety_controller_get_timing_monitor_count()
{
	return COUNT_OF(timings);
}

int safety_controller_get_analog_mon_name_by_index(uint32_t index, char *buffer, size_t buffsize)
{
	if (index >= COUNT_OF(analog_mons))
		return -1;

	if (buffsize == 0 || !buffer)
		return -1000;

	strncpy(buffer, analog_mons[index].name, buffsize);
	buffer[buffsize - 1] = 0;

	return 0;
}

int safety_controller_get_flag_name_by_index(uint32_t index, char *buffer, size_t buffsize)
{
	if (index >= COUNT_OF(flags))
		return -1;

	if (buffsize == 0 || !buffer)
		return -1000;

	strncpy(buffer, flags[index].name, buffsize);
	buffer[buffsize - 1] = 0;

	return 0;
}

int safety_controller_get_timing_mon_name_by_index(uint32_t index, char *buffer, size_t buffsize)
{
	if (index >= COUNT_OF(timings))
		return -1;

	if (buffsize == 0 || !buffer)
		return -1000;

	strncpy(buffer, timings[index].name, buffsize);
	buffer[buffsize - 1] = 0;

	return 0;
}

int safety_controller_get_flag_by_index(uint32_t index, bool *status, enum safety_flag *flag_enum)
{
	int ret = -1;

	if (!status && !flag_enum)
		return -1000;

	if (index < COUNT_OF(flags)) {
		if (status)
			*status = error_flag_get_status(&flags[index]);
		if (flag_enum)
			*flag_enum = flags[index].flag;

		ret = 0;
	}

	return ret;
}

int safety_controller_get_analog_mon_by_index(uint32_t index, struct analog_monitor_info *info)
{
	volatile struct analog_mon *mon;

	if (!info)
		return -1002;

	if (index >= COUNT_OF(analog_mons)) {
		info->status = ANALOG_MONITOR_ERROR;
		return -1001;
	}

	mon = &analog_mons[index];

	info->max = mon->max;
	info->min = mon->min;
	info->value = mon->value;
	info->timestamp = mon->timestamp;
	info->associated_flag = mon->associated_flag;

	if (!mon->valid) {
		info->status = ANALOG_MONITOR_INACTIVE;
	} else {
		if (mon->value > mon->max)
			info->status = ANALOG_MONITOR_OVER;
		else if (mon->value < mon->min)
			info->status = ANALOG_MONITOR_UNDER;
		else
			info->status = ANALOG_MONITOR_OK;
	}

	return 0;
}

int safety_controller_get_timing_mon_by_index(uint32_t index, struct timing_monitor_info *info)
{
	volatile struct timing_mon *mon;

	if (!info)
		return -1002;

	if (index >= COUNT_OF(timings)) {
		return -1001;
	}

	mon = &timings[index];

	info->max = mon->max_delta;
	info->min = mon->min_delta;
	info->enabled = mon->enabled;
	info->last_run = mon->last;
	info->delta = mon->calculated_delta;

	return 0;
}

int safety_controller_set_overtemp_limit(float over_temperature)
{
	set_overtemp_config(over_temperature);
	return 0;
}

float safety_controller_get_overtemp_limit(void)
{
	return safety_controller_overtemp_config.overtemp_deg_celsius;
}

/** @} */