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/*
* Copyright (c) 2019 Centaur Analytics, Inc
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT st_stm32_window_watchdog
#include <zephyr/drivers/watchdog.h>
#include <soc.h>
#include <stm32_ll_bus.h>
#include <stm32_ll_wwdg.h>
#include <stm32_ll_system.h>
#include <errno.h>
#include <zephyr/sys/__assert.h>
#include <zephyr/drivers/clock_control/stm32_clock_control.h>
#include <zephyr/drivers/clock_control.h>
#include <zephyr/irq.h>
#include <zephyr/sys_clock.h>
#include "wdt_wwdg_stm32.h"
#define LOG_LEVEL CONFIG_WDT_LOG_LEVEL
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(wdt_wwdg_stm32);
#define WWDG_INTERNAL_DIVIDER 4096U
#define WWDG_RESET_LIMIT WWDG_COUNTER_MIN
#define WWDG_COUNTER_MIN 0x40
#define WWDG_COUNTER_MAX 0x7f
#if defined WWDG_CFR_WDGTB_Pos
#define WWDG_PRESCALER_POS WWDG_CFR_WDGTB_Pos
#define WWDG_PRESCALER_MASK WWDG_CFR_WDGTB_Msk
#else
#error "WWDG CFR WDGTB position not defined for soc"
#endif
/*
* additionally to the internal divider, the clock is divided by a
* programmable prescaler.
*/
#if defined(LL_WWDG_PRESCALER_128)
#define WWDG_PRESCALER_EXPONENT_MAX 7 /* 2^7 = 128 */
#elif defined(LL_WWDG_PRESCALER_8)
#define WWDG_PRESCALER_EXPONENT_MAX 3 /* 2^3 = 8 */
#endif
/* The timeout of the WWDG in milliseconds is calculated by the below formula:
*
* t_WWDG = 1000 * ((counter & 0x3F) + 1) / f_WWDG (ms)
*
* where:
* - t_WWDG: WWDG timeout
* - counter: a value in [0x40, 0x7F] representing the cycles before timeout.
* Giving the counter a value below 0x40, will result in an
* immediate system reset. A reset is produced when the counter
* rolls over from 0x40 to 0x3F.
* - f_WWDG: the frequency of the WWDG clock. This can be calculated by the
* below formula:
* f_WWDG = f_PCLK / (4096 * prescaler) (Hz)
* where:
* - f_PCLK: the clock frequency of the system
* - 4096: the constant internal divider
* - prescaler: the programmable divider with valid values of 1, 2, 4 or 8,
* and for some series additionally 16, 32, 64 and 128
*
* The minimum timeout is calculated with:
* - counter = 0x40
* - prescaler = 1
* The maximum timeout is calculated with:
* - counter = 0x7F
* - prescaler = 8
*
* E.g. for f_PCLK = 2MHz
* t_WWDG_min = 1000 * ((0x40 & 0x3F) + 1) / (2000000 / (4096 * 1))
* = 2.048 ms
* t_WWDG_max = 1000 * ((0x7F & 0x3F) + 1) / (2000000 / (4096 * 8))
* = 1048.576 ms
*/
#define ABS_DIFF_UINT(a, b) ((a) > (b) ? (a) - (b) : (b) - (a))
#define WWDG_TIMEOUT_ERROR_MARGIN(__TIMEOUT__) (__TIMEOUT__ / 10)
#define IS_WWDG_TIMEOUT(__TIMEOUT_GOLDEN__, __TIMEOUT__) \
(__TIMEOUT__ - __TIMEOUT_GOLDEN__) < \
WWDG_TIMEOUT_ERROR_MARGIN(__TIMEOUT_GOLDEN__)
static void wwdg_stm32_irq_config(const struct device *dev);
static uint32_t wwdg_stm32_get_pclk(const struct device *dev)
{
const struct device *const clk = DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE);
const struct wwdg_stm32_config *cfg = WWDG_STM32_CFG(dev);
uint32_t pclk_rate;
if (clock_control_get_rate(clk, (clock_control_subsys_t) &cfg->pclken,
&pclk_rate) < 0) {
LOG_ERR("Failed call clock_control_get_rate");
return -EIO;
}
return pclk_rate;
}
/**
* @brief Calculates the timeout in microseconds.
*
* @param dev Pointer to device structure.
* @param prescaler_exp The prescaler exponent value(Base 2).
* @param counter The counter value.
* @return The timeout calculated in microseconds.
*/
static uint32_t wwdg_stm32_get_timeout(const struct device *dev,
uint32_t prescaler_exp,
uint32_t counter)
{
uint32_t divider = WWDG_INTERNAL_DIVIDER * (1 << prescaler_exp);
float f_wwdg = (float)wwdg_stm32_get_pclk(dev) / divider;
return USEC_PER_SEC * (((counter & 0x3F) + 1) / f_wwdg);
}
/**
* @brief Calculates prescaler & counter values.
*
* @param dev Pointer to device structure.
* @param timeout Timeout value in microseconds.
* @param prescaler_exp Pointer to prescaler exponent value(Base 2).
* @param counter Pointer to counter value.
*/
static void wwdg_stm32_convert_timeout(const struct device *dev,
uint32_t timeout,
uint32_t *prescaler_exp,
uint32_t *counter)
{
uint32_t clock_freq = wwdg_stm32_get_pclk(dev);
/* Convert timeout to seconds. */
float timeout_s = (float)timeout / USEC_PER_SEC;
float wwdg_freq;
*prescaler_exp = 0U;
*counter = 0;
for (*prescaler_exp = 0; *prescaler_exp <= WWDG_PRESCALER_EXPONENT_MAX;
(*prescaler_exp)++) {
wwdg_freq = ((float)clock_freq) / WWDG_INTERNAL_DIVIDER
/ (1 << *prescaler_exp);
/* +1 to ceil the result, which may lose from truncation */
*counter = (uint32_t)(timeout_s * wwdg_freq + 1) - 1;
*counter += WWDG_RESET_LIMIT;
if (*counter <= WWDG_COUNTER_MAX) {
return;
}
}
/* timeout longer than wwdg can provide, set to max possible value */
*counter = WWDG_COUNTER_MAX;
*prescaler_exp = WWDG_PRESCALER_EXPONENT_MAX;
}
static int wwdg_stm32_setup(const struct device *dev, uint8_t options)
{
WWDG_TypeDef *wwdg = WWDG_STM32_STRUCT(dev);
/* Deactivate running when debugger is attached. */
if (options & WDT_OPT_PAUSE_HALTED_BY_DBG) {
#if defined(CONFIG_SOC_SERIES_STM32F0X)
LL_APB1_GRP2_EnableClock(LL_APB1_GRP2_PERIPH_DBGMCU);
#elif defined(CONFIG_SOC_SERIES_STM32L0X)
LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_DBGMCU);
#elif defined(CONFIG_SOC_SERIES_STM32C0X) || defined(CONFIG_SOC_SERIES_STM32G0X)
LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_DBGMCU);
#endif
#if defined(CONFIG_SOC_SERIES_STM32H7X)
LL_DBGMCU_APB3_GRP1_FreezePeriph(LL_DBGMCU_APB3_GRP1_WWDG1_STOP);
#elif defined(CONFIG_SOC_SERIES_STM32MP1X)
LL_DBGMCU_APB1_GRP1_FreezePeriph(LL_DBGMCU_APB1_GRP1_WWDG1_STOP);
#else
LL_DBGMCU_APB1_GRP1_FreezePeriph(LL_DBGMCU_APB1_GRP1_WWDG_STOP);
#endif /* CONFIG_SOC_SERIES_STM32H7X */
}
if (options & WDT_OPT_PAUSE_IN_SLEEP) {
return -ENOTSUP;
}
/* Ensure that Early Wakeup Interrupt Flag is cleared */
LL_WWDG_ClearFlag_EWKUP(wwdg);
/* Enable the WWDG */
LL_WWDG_Enable(wwdg);
return 0;
}
static int wwdg_stm32_disable(const struct device *dev)
{
/* watchdog cannot be stopped once started unless SOC gets a reset */
ARG_UNUSED(dev);
return -EPERM;
}
static int wwdg_stm32_install_timeout(const struct device *dev,
const struct wdt_timeout_cfg *config)
{
struct wwdg_stm32_data *data = WWDG_STM32_DATA(dev);
WWDG_TypeDef *wwdg = WWDG_STM32_STRUCT(dev);
uint32_t timeout = config->window.max * USEC_PER_MSEC;
uint32_t calculated_timeout;
uint32_t prescaler_exp = 0U;
uint32_t counter = 0U;
if (config->callback != NULL) {
data->callback = config->callback;
}
wwdg_stm32_convert_timeout(dev, timeout, &prescaler_exp, &counter);
calculated_timeout = wwdg_stm32_get_timeout(dev, prescaler_exp, counter);
LOG_DBG("prescaler: %d", (1 << prescaler_exp));
LOG_DBG("Desired WDT: %d us", timeout);
LOG_DBG("Set WDT: %d us", calculated_timeout);
if (!(IS_WWDG_COUNTER(counter) &&
IS_WWDG_TIMEOUT(timeout, calculated_timeout))) {
/* One of the parameters provided is invalid */
return -EINVAL;
}
data->counter = counter;
/* Configure WWDG */
/* Set the programmable prescaler */
LL_WWDG_SetPrescaler(wwdg,
(prescaler_exp << WWDG_PRESCALER_POS) & WWDG_PRESCALER_MASK);
/* Set window the same as the counter to be able to feed the WWDG almost
* immediately
*/
LL_WWDG_SetWindow(wwdg, counter);
LL_WWDG_SetCounter(wwdg, counter);
return 0;
}
static int wwdg_stm32_feed(const struct device *dev, int channel_id)
{
WWDG_TypeDef *wwdg = WWDG_STM32_STRUCT(dev);
struct wwdg_stm32_data *data = WWDG_STM32_DATA(dev);
ARG_UNUSED(channel_id);
LL_WWDG_SetCounter(wwdg, data->counter);
return 0;
}
void wwdg_stm32_isr(const struct device *dev)
{
struct wwdg_stm32_data *data = WWDG_STM32_DATA(dev);
WWDG_TypeDef *wwdg = WWDG_STM32_STRUCT(dev);
if (LL_WWDG_IsEnabledIT_EWKUP(wwdg)) {
if (LL_WWDG_IsActiveFlag_EWKUP(wwdg)) {
LL_WWDG_ClearFlag_EWKUP(wwdg);
data->callback(dev, 0);
}
}
}
static const struct wdt_driver_api wwdg_stm32_api = {
.setup = wwdg_stm32_setup,
.disable = wwdg_stm32_disable,
.install_timeout = wwdg_stm32_install_timeout,
.feed = wwdg_stm32_feed,
};
static int wwdg_stm32_init(const struct device *dev)
{
const struct device *const clk = DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE);
const struct wwdg_stm32_config *cfg = WWDG_STM32_CFG(dev);
wwdg_stm32_irq_config(dev);
if (!device_is_ready(clk)) {
LOG_ERR("clock control device not ready");
return -ENODEV;
}
return clock_control_on(clk, (clock_control_subsys_t) &cfg->pclken);
}
static struct wwdg_stm32_data wwdg_stm32_dev_data = {
.counter = WWDG_RESET_LIMIT,
.callback = NULL
};
static struct wwdg_stm32_config wwdg_stm32_dev_config = {
.pclken = {
.enr = DT_INST_CLOCKS_CELL(0, bits),
.bus = DT_INST_CLOCKS_CELL(0, bus)
},
.Instance = (WWDG_TypeDef *)DT_INST_REG_ADDR(0),
};
DEVICE_DT_INST_DEFINE(0, wwdg_stm32_init, NULL,
&wwdg_stm32_dev_data, &wwdg_stm32_dev_config,
POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
&wwdg_stm32_api);
static void wwdg_stm32_irq_config(const struct device *dev)
{
WWDG_TypeDef *wwdg = WWDG_STM32_STRUCT(dev);
IRQ_CONNECT(DT_INST_IRQN(0),
DT_INST_IRQ(0, priority),
wwdg_stm32_isr, DEVICE_DT_INST_GET(0), 0);
irq_enable(DT_INST_IRQN(0));
LL_WWDG_EnableIT_EWKUP(wwdg);
}