drivers: watchdog: implement Smartbond watchdog driver

This patch adds watchdog driver for Renesas Smartbond SOCs.

Co-authored-by: Jerzy Kasenberg <jerzy.kasenberg@codecoup.pl>

Signed-off-by: Ben Lauret <ben.lauret.wm@renesas.com>

boards/arm/da1469x_dk_pro/da1469x_dk_pro.dts

@@ -59,6 +59,7 @@
 
 	aliases {
 		led0 = &red_led;
+		watchdog0 = &wdog;
 	};
 
 	sysclk: system-clock {

boards/arm/da1469x_dk_pro/da1469x_dk_pro.yaml

@@ -10,3 +10,4 @@ toolchain:
 supported:
   - arduino_gpio
   - gpio
+  - watchdog

drivers/watchdog/CMakeLists.txt

@@ -29,6 +29,7 @@ zephyr_library_sources_ifdef(CONFIG_WDT_SIFIVE wdt_sifive.c)
 zephyr_library_sources_ifdef(CONFIG_WDT_XEC wdt_mchp_xec.c)
 zephyr_library_sources_ifdef(CONFIG_WDT_COUNTER wdt_counter.c)
 zephyr_library_sources_ifdef(CONFIG_WDT_NXP_S32 wdt_nxp_s32.c)
+zephyr_library_sources_ifdef(CONFIG_WDT_SMARTBOND wdt_smartbond.c)
 
 zephyr_library_sources_ifdef(CONFIG_WDT_DW wdt_dw.c)
 

drivers/watchdog/Kconfig

@@ -96,4 +96,6 @@ source "drivers/watchdog/Kconfig.nxp_s32"
 
 source "drivers/watchdog/Kconfig.dw"
 
+source "drivers/watchdog/Kconfig.smartbond"
+
 endif # WATCHDOG

drivers/watchdog/Kconfig.smartbond

@@ -0,0 +1,26 @@
+# Smartbond watchdog driver config
+
+# Copyright (c) 2022 Renesas Electronics Corporation and/or its affiliates
+# SPDX-License-Identifier: Apache-2.0
+
+config WDT_SMARTBOND
+	bool "Watchdog Driver for Smartbond family of MCUs"
+	default y
+	depends on DT_HAS_RENESAS_SMARTBOND_WATCHDOG_ENABLED
+	help
+	  Enable watchdog driver for Smartbond line of MCUs
+
+config WDT_SMARTBOND_NMI
+	bool "NMI pre-reset interrupt enable"
+	default n
+	depends on WDT_SMARTBOND
+	select RUNTIME_NMI
+	help
+	  Watchdog timer generates NMI at value 0, and WDOG (SYS)
+	  reset at <= -16. Timer can be frozen/resumed using
+	  SET_FREEZE_REG[FRZ_WDOG]/RESET_FREEZE_REG[FRZ_WDOG].
+	  When not set:
+	  Watchdog timer generates a WDOG (SYS)
+	  reset at value 0 and can not be frozen by Software.
+	  Note that this bit can only be set to 1 by SW and
+	  only be reset with a WDOG (SYS) reset or SW reset.

drivers/watchdog/wdt_smartbond.c

@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2022 Renesas Electronics Corporation and/or its affiliates
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <soc.h>
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/watchdog.h>
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_REGISTER(wdog_smartbond, CONFIG_WDT_LOG_LEVEL);
+
+#define DT_DRV_COMPAT renesas_smartbond_watchdog
+
+/* driver data */
+struct wdog_smartbond_data {
+	/* Reload value calculated in setup */
+	uint32_t reload_val;
+#ifdef CONFIG_WDT_SMARTBOND_NMI
+	const struct device *wdog_device;
+	wdt_callback_t callback;
+#endif
+};
+
+static struct wdog_smartbond_data wdog_smartbond_dev_data = {};
+
+static int wdg_smartbond_setup(const struct device *dev, uint8_t options)
+{
+	ARG_UNUSED(dev);
+
+	if (options & WDT_OPT_PAUSE_IN_SLEEP) {
+		LOG_ERR("Watchdog pause in sleep is not supported");
+		return -ENOTSUP;
+	}
+	return 0;
+}
+
+static int wdg_smartbond_disable(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+
+	if (SYS_WDOG->WATCHDOG_CTRL_REG & SYS_WDOG_WATCHDOG_CTRL_REG_NMI_RST_Msk) {
+		/* watchdog cannot be stopped once started when NMI_RST is 1 */
+		return -EPERM;
+	}
+
+	GPREG->SET_FREEZE_REG = GPREG_SET_FREEZE_REG_FRZ_SYS_WDOG_Msk;
+	return 0;
+}
+
+#ifdef CONFIG_WDT_SMARTBOND_NMI
+extern void z_NmiHandlerSet(void (*pHandler)(void));
+
+static void wdog_smartbond_nmi_isr(void)
+{
+	if (wdog_smartbond_dev_data.callback) {
+		wdog_smartbond_dev_data.callback(wdog_smartbond_dev_data.wdog_device, 0);
+	}
+}
+#endif /* CONFIG_RUNTIME_NMI */
+
+static int wdg_smartbond_install_timeout(const struct device *dev,
+					 const struct wdt_timeout_cfg *config)
+{
+	struct wdog_smartbond_data *data = (struct wdog_smartbond_data *)(dev)->data;
+	uint32_t reload_val;
+
+#ifndef CONFIG_WDT_SMARTBOND_NMI
+	if (config->callback != NULL) {
+		return -ENOTSUP;
+	}
+#endif
+	/* For RC32K timer ticks every ~10ms, for RCX ~21ms */
+	if (CRG_TOP->CLK_RCX_REG & CRG_TOP_CLK_RCX_REG_RCX_ENABLE_Msk) {
+		reload_val = config->window.max / 21;
+	} else {
+		reload_val = config->window.max / 10;
+	}
+
+	if (reload_val < 1 || reload_val >= 0x2000 || config->window.min != 0) {
+		/* Out of range supported by watchdog */
+		LOG_ERR("Watchdog timeout out of range");
+		return -EINVAL;
+	}
+#if CONFIG_WDT_SMARTBOND_NMI
+	data->callback = config->callback;
+	data->wdog_device = dev;
+	z_NmiHandlerSet(wdog_smartbond_nmi_isr);
+	SYS_WDOG->WATCHDOG_CTRL_REG = 2;
+#else
+	SYS_WDOG->WATCHDOG_CTRL_REG = 2 | SYS_WDOG_WATCHDOG_CTRL_REG_NMI_RST_Msk;
+#endif
+
+	data->reload_val = reload_val;
+	while (SYS_WDOG->WATCHDOG_CTRL_REG & SYS_WDOG_WATCHDOG_CTRL_REG_WRITE_BUSY_Msk) {
+		/* wait */
+	}
+	SYS_WDOG->WATCHDOG_REG = reload_val;
+
+	return 0;
+}
+
+static int wdg_smartbond_feed(const struct device *dev, int channel_id)
+{
+	struct wdog_smartbond_data *data = (struct wdog_smartbond_data *)(dev)->data;
+
+	ARG_UNUSED(channel_id);
+
+	while (SYS_WDOG->WATCHDOG_CTRL_REG & SYS_WDOG_WATCHDOG_CTRL_REG_WRITE_BUSY_Msk) {
+		/* wait */
+	}
+	SYS_WDOG->WATCHDOG_REG = data->reload_val;
+
+	return 0;
+}
+
+static const struct wdt_driver_api wdg_smartbond_api = {
+	.setup = wdg_smartbond_setup,
+	.disable = wdg_smartbond_disable,
+	.install_timeout = wdg_smartbond_install_timeout,
+	.feed = wdg_smartbond_feed,
+};
+
+static int wdg_smartbond_init(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+
+#ifdef CONFIG_WDT_DISABLE_AT_BOOT
+	GPREG->SET_FREEZE_REG = GPREG_SET_FREEZE_REG_FRZ_SYS_WDOG_Msk;
+#endif
+
+	return 0;
+}
+
+DEVICE_DT_INST_DEFINE(0, wdg_smartbond_init, NULL, &wdog_smartbond_dev_data, NULL, POST_KERNEL,
+		      CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &wdg_smartbond_api);

dts/arm/renesas/smartbond/da1469x.dtsi

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022 Renesas Electronics Corporation
+ * Copyright (c) 2022 Renesas Electronics Corporation and/or its affiliates
  * SPDX-License-Identifier: Apache-2.0
  */
 
@@ -23,6 +23,7 @@
 		};
 	};
 
+
 	soc {
 		sram0: memory@20000000 {
 			compatible = "mmio-sram";
@@ -81,6 +82,12 @@
 			};
 		};
 
+		wdog: watchdog@50000700 {
+			compatible = "renesas,smartbond-watchdog";
+			reg = <0x50000700 0x8>;
+			status = "okay";
+		};
+
 		uart: uart@50020000 {
 			compatible = "renesas,smartbond-uart";
 			reg = <0x50020000 0x100>;

dts/bindings/watchdog/renesas,smartbond-watchdog.yaml

@@ -0,0 +1,12 @@
+# Copyright (c) 2022 Renesas Electronics Corporation and/or its affiliates
+# SPDX-License-Identifier: Apache-2.0
+
+description: Smartbond watchdog
+
+compatible: "renesas,smartbond-watchdog"
+
+include: base.yaml
+
+properties:
+  reg:
+    required: true