samd/machine_wdt: Add the machine.WDT class.

ports/samd/Makefile

@@ -97,6 +97,7 @@ SRC_C = \
 	machine_spi.c \
 	machine_timer.c \
 	machine_uart.c \
+	machine_wdt.c \
 	main.c \
 	modutime.c \
 	modmachine.c \
@@ -155,6 +156,7 @@ SRC_QSTR += \
 	machine_spi.c \
 	machine_timer.c \
 	machine_uart.c \
+	machine_wdt.c \
 	modutime.c \
 	modmachine.c \
 	modsamd.c \

ports/samd/machine_wdt.c

@@ -0,0 +1,141 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020-2021 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/runtime.h"
+#include "modmachine.h"
+
+#include "sam.h"
+
+#define MIN_TIMEOUT         512
+#define MAX_TIMEOUT         16384
+
+typedef struct _machine_wdt_obj_t {
+    mp_obj_base_t base;
+} machine_wdt_obj_t;
+
+extern mp_int_t log2i(mp_int_t num);
+
+STATIC const machine_wdt_obj_t machine_wdt = {{&machine_wdt_type}};
+
+STATIC void set_timeout(uint32_t timeout) {
+    // Set new timeout. Have to disable WDT first.
+
+    // Confine to the valid range
+    if (timeout < MIN_TIMEOUT) {
+        timeout = MIN_TIMEOUT;
+    } else if (timeout > MAX_TIMEOUT) {
+        timeout = MAX_TIMEOUT;
+    }
+
+    #if defined(MCU_SAMD21)
+    WDT->CTRL.reg = 0;
+    while (WDT->STATUS.reg & WDT_STATUS_SYNCBUSY) {
+    }
+    WDT->CONFIG.reg = log2i(timeout) - 3;
+    WDT->CTRL.reg = WDT_CTRL_ENABLE;
+    while (WDT->STATUS.reg & WDT_STATUS_SYNCBUSY) {
+    }
+    #elif defined(MCU_SAMD51)
+    WDT->CTRLA.reg = 0;
+    while (WDT->SYNCBUSY.reg & WDT_SYNCBUSY_ENABLE) {
+    }
+    WDT->CONFIG.reg = log2i(timeout) - 3;
+    WDT->CTRLA.reg = WDT_CTRLA_ENABLE;
+    while (WDT->SYNCBUSY.reg & WDT_SYNCBUSY_ENABLE) {
+    }
+    #endif
+}
+
+STATIC mp_obj_t machine_wdt_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
+    enum { ARG_id, ARG_timeout, ARG_lock };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_id, MP_ARG_INT, {.u_int = 0} },
+        { MP_QSTR_timeout, MP_ARG_INT, {.u_int = 5000} },
+    };
+
+    // Parse the arguments.
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    #if defined(MCU_SAMD51)
+    // Verify the WDT id. SAMD51 only, saving a few bytes for SAMD21
+    mp_int_t id = args[ARG_id].u_int;
+    if (id != 0) {
+        mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("WDT(%d) doesn't exist"), id);
+    }
+    #endif
+
+    // Start the watchdog (timeout is in milliseconds).
+    uint32_t timeout = args[ARG_timeout].u_int;
+    // Configure the WDT
+    #if defined(MCU_SAMD21)
+
+    // Enable APBx clocks and GCLK clock
+    PM->APBAMASK.reg |= PM_APBAMASK_WDT;
+    GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK8 | GCLK_CLKCTRL_ID_WDT;
+
+    #elif defined(MCU_SAMD51)
+
+    // Enable APBx clocks and 1kHz clock
+    MCLK->APBAMASK.reg |= MCLK_APBAMASK_WDT;
+    OSC32KCTRL->OSCULP32K.bit.EN1K = 1;
+
+    #endif
+
+    set_timeout(timeout);
+
+    return MP_OBJ_FROM_PTR(&machine_wdt);
+}
+
+STATIC mp_obj_t machine_wdt_feed(mp_obj_t self_in) {
+    (void)self_in;
+    WDT->CLEAR.reg = 0xa5;
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_wdt_feed_obj, machine_wdt_feed);
+
+STATIC mp_obj_t machine_wdt_timeout_ms(mp_obj_t self_in, mp_obj_t timout_in) {
+    uint32_t timeout = mp_obj_get_int(timout_in);
+
+    set_timeout(timeout);
+
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(machine_wdt_timeout_ms_obj, machine_wdt_timeout_ms);
+
+STATIC const mp_rom_map_elem_t machine_wdt_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_feed), MP_ROM_PTR(&machine_wdt_feed_obj) },
+    { MP_ROM_QSTR(MP_QSTR_timeout_ms), MP_ROM_PTR(&machine_wdt_timeout_ms_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(machine_wdt_locals_dict, machine_wdt_locals_dict_table);
+
+MP_DEFINE_CONST_OBJ_TYPE(
+    machine_wdt_type,
+    MP_QSTR_WDT,
+    MP_TYPE_FLAG_NONE,
+    make_new, machine_wdt_make_new,
+    locals_dict, &machine_wdt_locals_dict
+    );

ports/samd/modmachine.c

@@ -159,6 +159,7 @@ STATIC const mp_rom_map_elem_t machine_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_SPI),                 MP_ROM_PTR(&machine_spi_type) },
     { MP_ROM_QSTR(MP_QSTR_Timer),               MP_ROM_PTR(&machine_timer_type) },
     { MP_ROM_QSTR(MP_QSTR_UART),                MP_ROM_PTR(&machine_uart_type) },
+    { MP_ROM_QSTR(MP_QSTR_WDT),                 MP_ROM_PTR(&machine_wdt_type) },
 
     { MP_ROM_QSTR(MP_QSTR_idle),                MP_ROM_PTR(&machine_idle_obj) },
     { MP_ROM_QSTR(MP_QSTR_disable_irq),         MP_ROM_PTR(&machine_disable_irq_obj) },

ports/samd/modmachine.h

@@ -36,5 +36,6 @@ extern const mp_obj_type_t machine_pwm_type;
 extern const mp_obj_type_t machine_spi_type;
 extern const mp_obj_type_t machine_timer_type;
 extern const mp_obj_type_t machine_uart_type;
+extern const mp_obj_type_t machine_wdt_type;
 
 #endif // MICROPY_INCLUDED_SAMD_MODMACHINE_H