[watchdog, stm32wb, tests] Implement watchdog abstraction. Implement IWDG/WWDG drivers for STM32WB. Implement generic watchdog test

Author: AlexLanzano

.github/workflows/boards.yml

@@ -0,0 +1,31 @@
+name: Board Builds
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  boards:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        board: [stm32wb55xx_nucleo, pic32cz_curiosity_ultra, stm32h563zi_nucleo, stm32f411_blackpill, stm32c031_nucleo]
+        extra_cflags: ["", "-DWHAL_CFG_NO_TIMEOUT"]
+        include:
+          - board: stm32wb55xx_nucleo
+            extra_cflags: "-DBOARD_DMA"
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install ARM toolchain
+        run: sudo apt-get update && sudo apt-get install -y gcc-arm-none-eabi
+
+      - name: Build blinky
+        working-directory: examples/blinky
+        run: CFLAGS="${{ matrix.extra_cflags }}" make BOARD=${{ matrix.board }}
+
+      - name: Build tests
+        working-directory: tests
+        run: CFLAGS="${{ matrix.extra_cflags }}" make BOARD=${{ matrix.board }}

.github/workflows/ci.yml

@@ -0,0 +1,20 @@
+name: Core Tests
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  core-tests:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        extra_cflags: ["", "-DWHAL_CFG_NO_TIMEOUT"]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Build and run core tests
+        working-directory: tests/core
+        run: CFLAGS="${{ matrix.extra_cflags }}" make run

.github/workflows/core-tests.yml

@@ -0,0 +1,32 @@
+name: Peripheral Tests
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  peripheral-tests:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        include:
+          - board: stm32wb55xx_nucleo
+            peripherals: bmi270
+            tests: bmi270
+          - board: stm32wb55xx_nucleo
+            peripherals: spi_nor_w25q64
+            tests: flash
+          - board: stm32wb55xx_nucleo
+            peripherals: sdhc_spi_sdcard32gb
+            tests: block
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install ARM toolchain
+        run: sudo apt-get update && sudo apt-get install -y gcc-arm-none-eabi
+
+      - name: Build tests
+        working-directory: tests
+        run: make BOARD=${{ matrix.board }} PERIPHERALS="${{ matrix.peripherals }}" TESTS="${{ matrix.tests }}"

.github/workflows/peripheral-tests.yml

@@ -0,0 +1,27 @@
+name: Watchdog Tests
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  watchdog-tests:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        include:
+          - board: stm32wb55xx_nucleo
+            watchdog: iwdg
+          - board: stm32wb55xx_nucleo
+            watchdog: wwdg
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install ARM toolchain
+        run: sudo apt-get update && sudo apt-get install -y gcc-arm-none-eabi
+
+      - name: Build tests
+        working-directory: tests
+        run: make BOARD=${{ matrix.board }} TESTS=watchdog WATCHDOG=${{ matrix.watchdog }}

.github/workflows/watchdog-tests.yml

@@ -10,7 +10,9 @@ OBJCOPY = $(GCC_PATH)arm-none-eabi-objcopy
 CFLAGS += -Wall -Werror $(INCLUDE) -g3 \
           -ffreestanding -nostdlib -mcpu=cortex-m4 \
           -DPLATFORM_STM32WB -MMD -MP \
-          $(if $(DMA),-DBOARD_DMA)
+          $(if $(DMA),-DBOARD_DMA) \
+          $(if $(filter iwdg,$(WATCHDOG)),-DBOARD_WATCHDOG_IWDG) \
+          $(if $(filter wwdg,$(WATCHDOG)),-DBOARD_WATCHDOG_WWDG)
 LDFLAGS = --omagic -static
 
 LINKER_SCRIPT ?= $(_BOARD_DIR)/linker.ld
@@ -29,6 +31,7 @@ BOARD_SOURCE += $(wildcard $(WHAL_DIR)/src/*/flash.c)
 BOARD_SOURCE += $(wildcard $(WHAL_DIR)/src/*/spi.c)
 BOARD_SOURCE += $(wildcard $(WHAL_DIR)/src/*/i2c.c)
 BOARD_SOURCE += $(wildcard $(WHAL_DIR)/src/*/sensor.c)
+BOARD_SOURCE += $(wildcard $(WHAL_DIR)/src/*/watchdog.c)
 BOARD_SOURCE += $(wildcard $(WHAL_DIR)/src/*/rng.c)
 BOARD_SOURCE += $(wildcard $(WHAL_DIR)/src/*/crypto.c)
 BOARD_SOURCE += $(wildcard $(WHAL_DIR)/src/*/block.c)

boards/stm32wb55xx_nucleo/Makefile.inc

@@ -59,6 +59,9 @@ static const whal_Stm32wbRcc_Clk g_clocks[] = {
     {WHAL_STM32WB55_RNG_CLOCK},
     {WHAL_STM32WB55_AES1_CLOCK},
     {WHAL_STM32WB55_I2C1_CLOCK},
+#ifdef BOARD_WATCHDOG_WWDG
+    {WHAL_STM32WB55_WWDG_CLOCK},
+#endif
 };
 #define CLOCK_COUNT (sizeof(g_clocks) / sizeof(g_clocks[0]))
 
@@ -244,6 +247,27 @@ whal_Crypto g_whalCrypto = {
     },
 };
 
+#ifdef BOARD_WATCHDOG_IWDG
+whal_Watchdog g_whalWatchdog = {
+    WHAL_STM32WB55_IWDG_DEVICE,
+
+    .cfg = &(whal_Stm32wbIwdg_Cfg) {
+        .prescaler = WHAL_STM32WB_IWDG_PR_32,
+        .reload = 100,
+    },
+};
+#elif defined(BOARD_WATCHDOG_WWDG)
+whal_Watchdog g_whalWatchdog = {
+    WHAL_STM32WB55_WWDG_DEVICE,
+
+    .cfg = &(whal_Stm32wbWwdg_Cfg) {
+        .prescaler = WHAL_STM32WB_WWDG_TB_128,
+        .window = 0x7F,
+        .counter = 0x7F,
+    },
+};
+#endif
+
 void Board_WaitMs(size_t ms)
 {
     uint32_t startCount = g_tick;
@@ -276,6 +300,14 @@ whal_Error Board_Init(void)
         return err;
     }
 
+#ifdef BOARD_WATCHDOG_IWDG
+    /* Enable LSI osc required by the IWDG */
+    err = whal_Stm32wbRcc_Ext_EnableLsi(&g_whalClock, 1);
+    if (err) {
+        return err;
+    }
+#endif
+
     /* Enable clocks */
     for (size_t i = 0; i < CLOCK_COUNT; i++) {
         err = whal_Clock_Enable(&g_whalClock, &g_clocks[i]);
@@ -445,6 +477,13 @@ whal_Error Board_Deinit(void)
         return err;
     }
 
+#ifdef BOARD_WATCHDOG_IWDG
+    err = whal_Stm32wbRcc_Ext_EnableLsi(&g_whalClock, 0);
+    if (err) {
+        return err;
+    }
+#endif
+
     err = whal_Clock_Deinit(&g_whalClock);
     if (err) {
         return err;

boards/stm32wb55xx_nucleo/board.c

@@ -15,6 +15,7 @@ extern whal_Rng g_whalRng;
 extern whal_Crypto g_whalCrypto;
 extern whal_I2c g_whalI2c;
 extern whal_Irq g_whalIrq;
+extern whal_Watchdog g_whalWatchdog;
 
 extern whal_Timeout g_whalTimeout;
 extern volatile uint32_t g_tick;

boards/stm32wb55xx_nucleo/board.h

@@ -106,7 +106,18 @@ whal_Error Board_Init(void)
 
     return WHAL_SUCCESS;
 }
+```
+
+The watchdog is intentionally excluded from `Board_Init()` and `Board_Deinit()`.
+Once started, most watchdog peripherals cannot be stopped — if `Board_Init()`
+starts the watchdog, any delay before the application begins refreshing it will
+cause an unexpected reset. The application or test should call
+`whal_Watchdog_Init()` directly when it is ready to begin refreshing. The board
+still defines the `g_whalWatchdog` instance and enables any required clocks
+(e.g., WWDG APB clock, IWDG LSI oscillator) so the watchdog is ready to be
+started.
 
+```c
 whal_Error Board_Deinit(void)
 {
     whal_Error err;

docs/adding_a_board.md

@@ -1053,6 +1053,50 @@ a transfer needs to be cancelled.
 
 ---
 
+## Watchdog
+
+Header: `wolfHAL/watchdog/watchdog.h`
+
+The watchdog driver provides access to hardware watchdog timers that reset the
+system if not periodically refreshed. On most hardware, the watchdog cannot be
+stopped once started — only a system reset clears it.
+
+### Init
+
+Configure and start the watchdog. This typically involves:
+
+- Setting the prescaler and reload/counter values from the configuration
+- Enabling the watchdog peripheral
+
+On some hardware (e.g., STM32 IWDG), the watchdog must be started before its
+configuration registers can be written. The driver should handle this ordering
+internally.
+
+The board must enable any required clocks before calling Init. For example, the
+STM32 WWDG requires an APB clock, while the IWDG requires the LSI oscillator.
+
+The watchdog is NOT initialized in `Board_Init` — the test or application
+controls when it starts, since once started it cannot be stopped.
+
+### Deinit
+
+Shut down the watchdog. On hardware where the watchdog cannot be stopped (e.g.,
+STM32 IWDG), this function is a no-op.
+
+### Refresh
+
+Reload the watchdog counter to prevent a reset. Must be called periodically
+within the configured timeout window. The exact mechanism is hardware-specific
+(e.g., writing a reload key to IWDG_KR, or writing the counter value back to
+WWDG_CR).
+
+For window watchdogs, the refresh must occur within the valid window — refreshing
+too early or too late triggers a reset. The driver does not enforce window timing;
+it writes the reload value unconditionally and relies on the hardware to enforce
+the window.
+
+---
+
 ## EthPhy
 
 Header: `wolfHAL/eth_phy/eth_phy.h`