drivers: retained_mem: Add nRF GPREGRET driver

Adds a driver for the Nordic nRF GPREGRET registers and adds
entries to the SoCs for this peripheral.

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>

drivers/retained_mem/CMakeLists.txt

@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: Apache-2.0
 
 zephyr_library()
+zephyr_library_sources_ifdef(CONFIG_RETAINED_MEM_NRF_GPREGRET retained_mem_nrf_gpregret.c)

drivers/retained_mem/Kconfig

@@ -19,4 +19,6 @@ module = RETAINED_MEM
 module-str = retained_mem
 source "subsys/logging/Kconfig.template.log_config"
 
+source "drivers/retained_mem/Kconfig.nrf"
+
 endif # RETAINED_MEM

drivers/retained_mem/Kconfig.nrf

@@ -0,0 +1,10 @@
+# Copyright (c) 2023 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+config RETAINED_MEM_NRF_GPREGRET
+	bool "nRF GPREGRET driver"
+	default y
+	depends on DT_HAS_NORDIC_NRF_GPREGRET_ENABLED
+	help
+	  Enable driver for Nordic nRF GPREGRET-based retained memory
+	  register support.

drivers/retained_mem/retained_mem_nrf_gpregret.c

@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2023, Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT nordic_nrf_gpregret
+
+#include <string.h>
+#include <zephyr/device.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/drivers/retained_mem.h>
+#include <zephyr/kernel.h>
+#include <zephyr/sys/util.h>
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_REGISTER(retained_mem_nrf_gpregret, CONFIG_RETAINED_MEM_LOG_LEVEL);
+
+#ifdef CONFIG_MULTITHREADING
+struct nrf_gpregret_data {
+	struct k_mutex lock;
+};
+#endif
+
+struct nrf_gpregret_config {
+	uint8_t *addr;
+	size_t size;
+};
+
+static inline void nrf_gpregret_lock_take(const struct device *dev)
+{
+#ifdef CONFIG_MULTITHREADING
+	struct nrf_gpregret_data *data = dev->data;
+
+	k_mutex_lock(&data->lock, K_FOREVER);
+#else
+	ARG_UNUSED(dev);
+#endif
+}
+
+static inline void nrf_gpregret_lock_release(const struct device *dev)
+{
+#ifdef CONFIG_MULTITHREADING
+	struct nrf_gpregret_data *data = dev->data;
+
+	k_mutex_unlock(&data->lock);
+#else
+	ARG_UNUSED(dev);
+#endif
+}
+
+static int nrf_gpregret_init(const struct device *dev)
+{
+#ifdef CONFIG_MULTITHREADING
+	struct nrf_gpregret_data *data = dev->data;
+
+	k_mutex_init(&data->lock);
+#endif
+
+	return 0;
+}
+
+static ssize_t nrf_gpregret_size(const struct device *dev)
+{
+	const struct nrf_gpregret_config *config = dev->config;
+
+	return (ssize_t)config->size;
+}
+
+static int nrf_gpregret_read(const struct device *dev, off_t offset, uint8_t *buffer, size_t size)
+{
+	const struct nrf_gpregret_config *config = dev->config;
+
+	nrf_gpregret_lock_take(dev);
+
+	memcpy(buffer, (config->addr + offset), size);
+
+	nrf_gpregret_lock_release(dev);
+
+	return 0;
+}
+
+static int nrf_gpregret_write(const struct device *dev, off_t offset, const uint8_t *buffer,
+			      size_t size)
+{
+	const struct nrf_gpregret_config *config = dev->config;
+
+	nrf_gpregret_lock_take(dev);
+
+	memcpy((config->addr + offset), buffer, size);
+
+	nrf_gpregret_lock_release(dev);
+
+	return 0;
+}
+
+static int nrf_gpregret_clear(const struct device *dev)
+{
+	const struct nrf_gpregret_config *config = dev->config;
+
+	nrf_gpregret_lock_take(dev);
+
+	memset(config->addr, 0, config->size);
+
+	nrf_gpregret_lock_release(dev);
+
+	return 0;
+}
+
+static const struct retained_mem_driver_api nrf_gpregret_api = {
+	.size = nrf_gpregret_size,
+	.read = nrf_gpregret_read,
+	.write = nrf_gpregret_write,
+	.clear = nrf_gpregret_clear,
+};
+
+#define NRF_GPREGRET_DEVICE(inst)						\
+	IF_ENABLED(CONFIG_MULTITHREADING,					\
+		   (static struct nrf_gpregret_data nrf_gpregret_data_##inst;)	\
+	)									\
+	static const struct nrf_gpregret_config nrf_gpregret_config_##inst = {	\
+		.addr = (uint8_t *)DT_INST_REG_ADDR(inst),			\
+		.size = DT_INST_REG_SIZE(inst),					\
+	};									\
+	DEVICE_DT_INST_DEFINE(inst,						\
+			      &nrf_gpregret_init,				\
+			      NULL,						\
+			      COND_CODE_1(CONFIG_MULTITHREADING,		\
+					  (&nrf_gpregret_data_##inst), (NULL)	\
+			      ),						\
+			      &nrf_gpregret_config_##inst,			\
+			      POST_KERNEL,					\
+			      CONFIG_RETAINED_MEM_INIT_PRIORITY,		\
+			      &nrf_gpregret_api);
+
+DT_INST_FOREACH_STATUS_OKAY(NRF_GPREGRET_DEVICE)

dts/arm/nordic/nrf51822.dtsi

@@ -42,6 +42,14 @@
 			reg = <0x40000000 0x1000>;
 			interrupts = <0 NRF_DEFAULT_IRQ_PRIORITY>;
 			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			gpregret1: gpregret1@4000051c {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x4000051c 0x1>;
+				status = "okay";
+			};
 		};
 
 		clock: clock@40000000 {

dts/arm/nordic/nrf52805.dtsi

@@ -53,6 +53,20 @@
 			reg = <0x40000000 0x1000>;
 			interrupts = <0 NRF_DEFAULT_IRQ_PRIORITY>;
 			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			gpregret1: gpregret1@4000051c {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x4000051c 0x1>;
+				status = "okay";
+			};
+
+			gpregret2: gpregret2@40000520 {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x40000520 0x1>;
+				status = "okay";
+			};
 		};
 
 		bprot: bprot@40000000 {

dts/arm/nordic/nrf52810.dtsi

@@ -57,6 +57,20 @@
 			reg = <0x40000000 0x1000>;
 			interrupts = <0 NRF_DEFAULT_IRQ_PRIORITY>;
 			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			gpregret1: gpregret1@4000051c {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x4000051c 0x1>;
+				status = "okay";
+			};
+
+			gpregret2: gpregret2@40000520 {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x40000520 0x1>;
+				status = "okay";
+			};
 		};
 
 		bprot: bprot@40000000 {

dts/arm/nordic/nrf52811.dtsi

@@ -61,6 +61,20 @@
 			reg = <0x40000000 0x1000>;
 			interrupts = <0 NRF_DEFAULT_IRQ_PRIORITY>;
 			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			gpregret1: gpregret1@4000051c {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x4000051c 0x1>;
+				status = "okay";
+			};
+
+			gpregret2: gpregret2@40000520 {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x40000520 0x1>;
+				status = "okay";
+			};
 		};
 
 		bprot: bprot@40000000 {

dts/arm/nordic/nrf52820.dtsi

@@ -62,6 +62,20 @@
 			reg = <0x40000000 0x1000>;
 			interrupts = <0 NRF_DEFAULT_IRQ_PRIORITY>;
 			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			gpregret1: gpregret1@4000051c {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x4000051c 0x1>;
+				status = "okay";
+			};
+
+			gpregret2: gpregret2@40000520 {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x40000520 0x1>;
+				status = "okay";
+			};
 		};
 
 		radio: radio@40001000 {

dts/arm/nordic/nrf52832.dtsi

@@ -57,6 +57,20 @@
 			reg = <0x40000000 0x1000>;
 			interrupts = <0 NRF_DEFAULT_IRQ_PRIORITY>;
 			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			gpregret1: gpregret1@4000051c {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x4000051c 0x1>;
+				status = "okay";
+			};
+
+			gpregret2: gpregret2@40000520 {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x40000520 0x1>;
+				status = "okay";
+			};
 		};
 
 		bprot: bprot@40000000 {

dts/arm/nordic/nrf52833.dtsi

@@ -61,6 +61,20 @@
 			reg = <0x40000000 0x1000>;
 			interrupts = <0 NRF_DEFAULT_IRQ_PRIORITY>;
 			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			gpregret1: gpregret1@4000051c {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x4000051c 0x1>;
+				status = "okay";
+			};
+
+			gpregret2: gpregret2@40000520 {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x40000520 0x1>;
+				status = "okay";
+			};
 		};
 
 		radio: radio@40001000 {

dts/arm/nordic/nrf52840.dtsi

@@ -57,6 +57,20 @@
 			reg = <0x40000000 0x1000>;
 			interrupts = <0 NRF_DEFAULT_IRQ_PRIORITY>;
 			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			gpregret1: gpregret1@4000051c {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x4000051c 0x1>;
+				status = "okay";
+			};
+
+			gpregret2: gpregret2@40000520 {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x40000520 0x1>;
+				status = "okay";
+			};
 		};
 
 		radio: radio@40001000 {

dts/arm/nordic/nrf5340_cpuapp_peripherals.dtsi

@@ -34,6 +34,20 @@ power: power@5000 {
 	reg = <0x5000 0x1000>;
 	interrupts = <5 NRF_DEFAULT_IRQ_PRIORITY>;
 	status = "okay";
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	gpregret1: gpregret1@551c {
+		compatible = "nordic,nrf-gpregret";
+		reg = <0x551c 0x1>;
+		status = "okay";
+	};
+
+	gpregret2: gpregret2@5520 {
+		compatible = "nordic,nrf-gpregret";
+		reg = <0x5520 0x1>;
+		status = "okay";
+	};
 };
 
 reset: reset-controller@5000 {

dts/arm/nordic/nrf5340_cpunet.dtsi

@@ -65,6 +65,20 @@
 			reg = <0x41005000 0x1000>;
 			interrupts = <5 NRF_DEFAULT_IRQ_PRIORITY>;
 			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			gpregret1: gpregret1@4100551c {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x4100551c 0x1>;
+				status = "okay";
+			};
+
+			gpregret2: gpregret2@41005520 {
+				compatible = "nordic,nrf-gpregret";
+				reg = <0x41005520 0x1>;
+				status = "okay";
+			};
 		};
 
 		radio: radio@41008000 {

dts/arm/nordic/nrf9160_common.dtsi

@@ -339,6 +339,20 @@ power: power@5000 {
 	reg = <0x5000 0x1000>;
 	interrupts = <5 NRF_DEFAULT_IRQ_PRIORITY>;
 	status = "okay";
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	gpregret1: gpregret1@551c {
+		compatible = "nordic,nrf-gpregret";
+		reg = <0x551c 0x1>;
+		status = "okay";
+	};
+
+	gpregret2: gpregret2@5520 {
+		compatible = "nordic,nrf-gpregret";
+		reg = <0x5520 0x1>;
+		status = "okay";
+	};
 };
 
 wdt: wdt0: watchdog@18000 {

dts/bindings/retained_mem/nordic,nrf-gpreget.yaml

@@ -0,0 +1,12 @@
+# Copyright (c) 2023 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+description: Nordic GPREGRET (General Purpose Register Retention) device.
+
+compatible: "nordic,nrf-gpregret"
+
+include: base.yaml
+
+properties:
+  reg:
+    required: true