Nuvoton: Support watchdog on M251/M261 series

targets/TARGET_NUVOTON/TARGET_M251/CMakeLists.txt

@@ -60,6 +60,7 @@ target_sources(mbed-m251
         sleep.c
         spi_api.c
         us_ticker.c
+        watchdog_api.c
 )
 
 target_include_directories(mbed-m251

targets/TARGET_NUVOTON/TARGET_M251/watchdog_api.c

@@ -0,0 +1,234 @@
+/*
+ * Copyright (c) 2019-2020 Nuvoton Technology Corporation
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "watchdog_api.h"
+
+#if DEVICE_WATCHDOG
+
+#include "cmsis.h"
+
+/* Watchdog clock per second */
+#if MBED_CONF_TARGET_LXT_PRESENT
+#define NU_WDTCLK_PER_SEC           (__LXT)
+#define NU_WDTCLK_PER_SEC_MAX       (__LXT)
+#define NU_WDTCLK_PER_SEC_MIN       (__LXT)
+#else
+#define NU_WDTCLK_PER_SEC           (__LIRC)
+#define NU_WDTCLK_PER_SEC_MAX       ((uint32_t) ((__LIRC) * 1.15f))
+#define NU_WDTCLK_PER_SEC_MIN       ((uint32_t) ((__LIRC) * 0.85f))
+#endif
+
+/* Convert watchdog clock to nearest ms */
+#define NU_WDTCLK2MS(WDTCLK)        (((WDTCLK) * 1000 + ((NU_WDTCLK_PER_SEC) / 2)) / (NU_WDTCLK_PER_SEC))
+
+/* Convert ms to nearest watchdog clock */
+#define NU_MS2WDTCLK(MS)            (((MS) * (NU_WDTCLK_PER_SEC) + 500) / 1000)
+
+/* List of hardware-supported watchdog timeout in clocks */
+#define NU_WDT_16CLK                    16
+#define NU_WDT_64CLK                    64
+#define NU_WDT_256CLK                   256
+#define NU_WDT_1024CLK                  1024
+#define NU_WDT_4096CLK                  4096
+#define NU_WDT_16384CLK                 16384
+#define NU_WDT_65536CLK                 65536
+#define NU_WDT_262144CLK                262144
+
+/* Watchdog reset delay
+ *
+ * 1. Cannot be too small. This is to avoid premature WDT reset in pieces of timeout cascading.
+ * 2. Cannot be too large. This is to pass Greentea reset_reason/watchdog_reset tests, which have e.g. 50~100 reset delay tolerance.
+ */
+#define NU_WDT_RESET_DELAY_RSTDSEL      WDT_RESET_DELAY_130CLK
+
+/* Support watchdog timeout values beyond H/W
+ *
+ * Watchdog Timer H/W just supports timeout values of 2^4, 2^6, ..., 2^18 clocks.
+ * To extend the support range to 1 and UINT32_MAX, we cascade multiple small timeouts to
+ * reach one large timeout specified in hal_watchdog_init.
+ */
+
+/* Track if WDT H/W has been initialized */
+static bool wdt_hw_inited = 0;
+/* Hold initially-configured timeout in hal_watchdog_init */
+static uint32_t wdt_timeout_reload_ms = 0;
+/* Track remaining timeout for cascading */
+static uint32_t wdt_timeout_rmn_clk = 0;
+
+static void watchdog_setup_cascade_timeout(void);
+static void WDT_IRQHandler(void);
+
+watchdog_status_t hal_watchdog_init(const watchdog_config_t *config)
+{
+    /* Check validity of arguments */
+    if (! config || ! config->timeout_ms) {
+        return WATCHDOG_STATUS_INVALID_ARGUMENT;
+    }
+
+    wdt_timeout_reload_ms = config->timeout_ms;
+    wdt_timeout_rmn_clk = NU_MS2WDTCLK(wdt_timeout_reload_ms);
+
+    if (! wdt_hw_inited) {
+        wdt_hw_inited = 1;
+
+        SYS_UnlockReg();
+
+        /* Enable IP module clock */
+        CLK_EnableModuleClock(WDT_MODULE);
+
+        /* Select IP clock source */
+#if MBED_CONF_TARGET_LXT_PRESENT
+        CLK_SetModuleClock(WDT_MODULE, CLK_CLKSEL1_WDTSEL_LXT, 0);
+#else
+        CLK_SetModuleClock(WDT_MODULE, CLK_CLKSEL1_WDTSEL_LIRC, 0);
+#endif
+
+        SYS_LockReg();
+
+        /* Set up IP interrupt */
+        NVIC_SetVector(WDT_IRQn, (uint32_t) WDT_IRQHandler);
+        NVIC_EnableIRQ(WDT_IRQn);
+    }
+
+    watchdog_setup_cascade_timeout();
+
+    return WATCHDOG_STATUS_OK;
+}
+
+void hal_watchdog_kick(void)
+{
+    /* If a watchdog is not running, this function does nothing */
+    if (!(WDT->CTL & WDT_CTL_WDTEN_Msk)) {
+        return;
+    }
+
+    wdt_timeout_rmn_clk = NU_MS2WDTCLK(wdt_timeout_reload_ms);
+    watchdog_setup_cascade_timeout();
+}
+
+watchdog_status_t hal_watchdog_stop(void)
+{
+    SYS_UnlockReg();
+
+    /* Clear all flags & Disable interrupt & Disable WDT */
+    WDT->CTL = (WDT->CTL & ~(WDT_CTL_WDTEN_Msk | WDT_CTL_INTEN_Msk)) | (WDT_CTL_WKF_Msk | WDT_CTL_IF_Msk | WDT_CTL_RSTF_Msk);
+
+    SYS_LockReg();
+
+    return WATCHDOG_STATUS_OK;
+}
+
+uint32_t hal_watchdog_get_reload_value(void)
+{
+    return wdt_timeout_reload_ms;
+}
+
+watchdog_features_t hal_watchdog_get_platform_features(void)
+{
+    watchdog_features_t wdt_feat;
+
+    /* We can support timeout values between 1 and UINT32_MAX by cascading. */
+    wdt_feat.max_timeout = UINT32_MAX;
+    /* Support re-configuring watchdog timer */
+    wdt_feat.update_config = 1;
+    /* Support stopping watchdog timer */
+    wdt_feat.disable_watchdog = 1;
+    /* Typical frequency of not calibrated watchdog clock in Hz */
+    wdt_feat.clock_typical_frequency = NU_WDTCLK_PER_SEC;
+    /* Maximum frequency of not calibrated watchdog clock in Hz */
+    wdt_feat.clock_max_frequency = NU_WDTCLK_PER_SEC_MAX;
+
+    return wdt_feat;
+}
+
+static void watchdog_setup_cascade_timeout(void)
+{
+    uint32_t wdt_timeout_clk_toutsel;
+
+    if (wdt_timeout_rmn_clk >= NU_WDT_262144CLK) {
+        wdt_timeout_rmn_clk -= NU_WDT_262144CLK;
+        wdt_timeout_clk_toutsel = WDT_TIMEOUT_2POW18;
+    } else if (wdt_timeout_rmn_clk >= NU_WDT_65536CLK) {
+        wdt_timeout_rmn_clk -= NU_WDT_65536CLK;
+        wdt_timeout_clk_toutsel = WDT_TIMEOUT_2POW16;
+    } else if (wdt_timeout_rmn_clk >= NU_WDT_16384CLK) {
+        wdt_timeout_rmn_clk -= NU_WDT_16384CLK;
+        wdt_timeout_clk_toutsel = WDT_TIMEOUT_2POW14;
+    } else if (wdt_timeout_rmn_clk >= NU_WDT_4096CLK) {
+        wdt_timeout_rmn_clk -= NU_WDT_4096CLK;
+        wdt_timeout_clk_toutsel = WDT_TIMEOUT_2POW12;
+    } else if (wdt_timeout_rmn_clk >= NU_WDT_1024CLK) {
+        wdt_timeout_rmn_clk -= NU_WDT_1024CLK;
+        wdt_timeout_clk_toutsel = WDT_TIMEOUT_2POW10;
+    } else if (wdt_timeout_rmn_clk >= NU_WDT_256CLK) {
+        wdt_timeout_rmn_clk -= NU_WDT_256CLK;
+        wdt_timeout_clk_toutsel = WDT_TIMEOUT_2POW8;
+    } else if (wdt_timeout_rmn_clk >= NU_WDT_64CLK) {
+        wdt_timeout_rmn_clk -= NU_WDT_64CLK;
+        wdt_timeout_clk_toutsel = WDT_TIMEOUT_2POW6;
+    } else if (wdt_timeout_rmn_clk >= NU_WDT_16CLK) {
+        wdt_timeout_rmn_clk -= NU_WDT_16CLK;
+        wdt_timeout_clk_toutsel = WDT_TIMEOUT_2POW4;
+    } else if (wdt_timeout_rmn_clk) {
+        wdt_timeout_rmn_clk = 0;
+        wdt_timeout_clk_toutsel = WDT_TIMEOUT_2POW4;
+    } else {
+        /* WDT has timed-out and will restart system soon. We just disable interrupt to escape
+         * getting stuck in WDT ISR. */
+        SYS_UnlockReg();
+
+        /* Clear all flags & Disable interrupt */
+        WDT->CTL = (WDT->CTL & ~WDT_CTL_INTEN_Msk) | (WDT_CTL_WKF_Msk | WDT_CTL_IF_Msk | WDT_CTL_RSTF_Msk);
+
+        SYS_LockReg();
+        return;
+    }
+
+    SYS_UnlockReg();
+
+    /* Configure reset delay on timeout */
+    WDT->ALTCTL = NU_WDT_RESET_DELAY_RSTDSEL;
+
+    /* Reset watchdog timer */
+    WDT_RESET_COUNTER();
+
+    /* Configure another piece of cascaded WDT timeout */
+    WDT->CTL = wdt_timeout_clk_toutsel |                    // Timeout interval
+        WDT_CTL_WDTEN_Msk |                                 // Enable watchdog timer
+        WDT_CTL_INTEN_Msk |                                 // Enable interrupt
+        WDT_CTL_WKF_Msk |                                   // Clear wake-up flag
+        WDT_CTL_WKEN_Msk |                                  // Enable wake-up on timeout
+        WDT_CTL_IF_Msk |                                    // Clear interrupt flag
+        WDT_CTL_RSTF_Msk |                                  // Clear reset flag
+        WDT_CTL_RSTEN_Msk;                                  // Enable reset always to address cascaded timeout failure in interrupt disabled scenario e.g. Hard Fault
+
+    SYS_LockReg();
+}
+
+void WDT_IRQHandler(void)
+{
+    /* Check WDT interrupt flag */
+    if (WDT_GET_TIMEOUT_INT_FLAG()) {
+        /* Continue another piece of cascaded WDT timeout */
+        watchdog_setup_cascade_timeout();
+    } else {
+        /* Clear all flags */
+        WDT->CTL |= (WDT_CTL_WKF_Msk | WDT_CTL_IF_Msk | WDT_CTL_RSTF_Msk);
+    }
+}
+
+#endif

targets/TARGET_NUVOTON/TARGET_M261/CMakeLists.txt

@@ -68,6 +68,7 @@ target_sources(mbed-m261
         spi_api.c
         trng_api.cpp
         us_ticker.c
+        watchdog_api.c
 
         crypto/crypto-misc.cpp
 )