| /* |
| * Copyright (c) 2019 Centaur Analytics, Inc |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| */ |
| |
| #include <drivers/watchdog.h> |
| #include <soc.h> |
| #include <errno.h> |
| #include <assert.h> |
| #include <drivers/clock_control/stm32_clock_control.h> |
| #include <drivers/clock_control.h> |
| |
| #include "wdt_wwdg_stm32.h" |
| |
| #include <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 |
| |
| /* 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 |
| * |
| * The minimum timeout is calculated with: |
| * - counter = 0x40 |
| * - prescaler = 1 |
| * The maximim 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 (100 * USEC_PER_MSEC) |
| #define IS_WWDG_TIMEOUT(__TIMEOUT_GOLDEN__, __TIMEOUT__) \ |
| (ABS_DIFF_UINT(__TIMEOUT_GOLDEN__, __TIMEOUT__) < \ |
| WWDG_TIMEOUT_ERROR_MARGIN) |
| |
| static void wwdg_stm32_irq_config(struct device *dev); |
| |
| static u32_t wwdg_stm32_get_pclk(struct device *dev) |
| { |
| struct device *clk = device_get_binding(STM32_CLOCK_CONTROL_NAME); |
| const struct wwdg_stm32_config *cfg = WWDG_STM32_CFG(dev); |
| u32_t pclk_rate; |
| |
| __ASSERT_NO_MSG(clk); |
| |
| 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 The prescaler value. |
| * @param counter The counter value. |
| * @return The timeout calculated in microseconds. |
| */ |
| static u32_t wwdg_stm32_get_timeout(struct device *dev, u32_t prescaler, |
| u32_t counter) |
| { |
| u32_t divider = WWDG_INTERNAL_DIVIDER * (1 << (prescaler >> 7)); |
| 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 Pointer to prescaler value. |
| * @param counter Pointer to counter value. |
| */ |
| static void wwdg_stm32_convert_timeout(struct device *dev, u32_t timeout, |
| u32_t *prescaler, |
| u32_t *counter) |
| { |
| u32_t clock_freq = wwdg_stm32_get_pclk(dev); |
| u8_t divider = 0U; |
| u8_t shift = 3U; |
| |
| /* Convert timeout to seconds. */ |
| float timeout_s = (float)timeout / USEC_PER_SEC; |
| float wwdg_freq; |
| |
| *prescaler = 0; |
| *counter = 0; |
| |
| for (divider = 8; divider >= 1; divider >>= 1) { |
| wwdg_freq = ((float)clock_freq) / WWDG_INTERNAL_DIVIDER / divider; |
| /* +1 to ceil the result, which may lose from truncation */ |
| *counter = (u32_t)(timeout_s * wwdg_freq + 1) - 1; |
| *counter |= WWDG_RESET_LIMIT; |
| *prescaler = shift << 7; |
| |
| if (*counter <= WWDG_COUNTER_MAX) { |
| break; |
| } |
| |
| shift--; |
| } |
| } |
| |
| static int wwdg_stm32_setup(struct device *dev, u8_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); |
| #endif |
| LL_DBGMCU_APB1_GRP1_FreezePeriph(LL_DBGMCU_APB1_GRP1_WWDG_STOP); |
| } |
| |
| 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(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(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); |
| u32_t timeout = config->window.max * USEC_PER_MSEC; |
| u32_t calculated_timeout; |
| u32_t prescaler = 0U; |
| u32_t counter = 0U; |
| |
| if (config->callback != NULL) { |
| data->callback = config->callback; |
| } |
| |
| wwdg_stm32_convert_timeout(dev, timeout, &prescaler, &counter); |
| |
| calculated_timeout = wwdg_stm32_get_timeout(dev, prescaler, counter); |
| if (!(IS_WWDG_PRESCALER(prescaler) && 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); |
| |
| /* 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(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(void *arg) |
| { |
| struct device *const dev = (struct device *)arg; |
| 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(struct device *dev) |
| { |
| struct device *clk = device_get_binding(STM32_CLOCK_CONTROL_NAME); |
| const struct wwdg_stm32_config *cfg = WWDG_STM32_CFG(dev); |
| |
| __ASSERT_NO_MSG(clk); |
| |
| clock_control_on(clk, (clock_control_subsys_t *) &cfg->pclken); |
| |
| wwdg_stm32_irq_config(dev); |
| |
| return 0; |
| } |
| |
| 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_WWDT_0_CLOCK_BITS, |
| .bus = DT_WWDT_0_CLOCK_BUS |
| }, |
| .Instance = (WWDG_TypeDef *)DT_WWDT_0_BASE_ADDRESS, |
| }; |
| |
| DEVICE_AND_API_INIT(wwdg_stm32, DT_WWDT_0_NAME, |
| wwdg_stm32_init, &wwdg_stm32_dev_data, &wwdg_stm32_dev_config, |
| POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE, |
| &wwdg_stm32_api); |
| |
| static void wwdg_stm32_irq_config(struct device *dev) |
| { |
| WWDG_TypeDef *wwdg = WWDG_STM32_STRUCT(dev); |
| |
| IRQ_CONNECT(DT_WWDT_0_IRQ, DT_WWDT_0_IRQ_PRI, |
| wwdg_stm32_isr, DEVICE_GET(wwdg_stm32), 0); |
| irq_enable(DT_WWDT_0_IRQ); |
| LL_WWDG_EnableIT_EWKUP(wwdg); |
| } |