drivers: entropy: add iproc_rng200 (rpi_5) random generator driver

Add driver for iproc_rng200 entropy generator.
This device is used by rpi_5.

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

boards/raspberrypi/rpi_5/rpi_5.dts

@@ -24,6 +24,7 @@
 		zephyr,console = &uart10;
 		zephyr,shell-uart = &uart10;
 		zephyr,pcie-controller = &pcie1;
+		zephyr,entropy = &rng;
 	};
 
 	leds {

drivers/entropy/CMakeLists.txt

@@ -16,6 +16,7 @@ endif()
 zephyr_library_sources_ifdef(CONFIG_USERSPACE entropy_handlers.c)
 
 # zephyr-keep-sorted-start
+zephyr_library_sources_ifdef(CONFIG_ENTROPY_BRCM_IPROC_RNG200   entropy_iproc_rng200.c)
 zephyr_library_sources_ifdef(CONFIG_ENTROPY_BT_HCI              entropy_bt_hci.c)
 zephyr_library_sources_ifdef(CONFIG_ENTROPY_CC13XX_CC26XX_RNG   entropy_cc13xx_cc26xx.c)
 zephyr_library_sources_ifdef(CONFIG_ENTROPY_ESP32_RNG           entropy_esp32.c)

drivers/entropy/Kconfig

@@ -26,6 +26,7 @@ source "drivers/entropy/Kconfig.bt_hci"
 source "drivers/entropy/Kconfig.cc13xx_cc26xx"
 source "drivers/entropy/Kconfig.esp32"
 source "drivers/entropy/Kconfig.gecko"
+source "drivers/entropy/Kconfig.iproc"
 source "drivers/entropy/Kconfig.litex"
 source "drivers/entropy/Kconfig.max32"
 source "drivers/entropy/Kconfig.maxq10xx"

drivers/entropy/Kconfig.iproc

@@ -0,0 +1,10 @@
+# Copyright (c) 2025 TOKITA Hiroshi
+# SPDX-License-Identifier: Apache-2.0
+
+config ENTROPY_BRCM_IPROC_RNG200
+	bool "Broadcom iProc RNG200 driver"
+	default y
+	depends on DT_HAS_BRCM_IPROC_RNG200_ENABLED
+	select ENTROPY_HAS_DRIVER
+	help
+	  Enable the Broadcom iProc RNG200 random number generator

drivers/entropy/entropy_iproc_rng200.c

@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2025 TOKITA Hiroshi
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT brcm_iproc_rng200
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(iproc_rng200_entropy, CONFIG_ENTROPY_LOG_LEVEL);
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/entropy.h>
+#include <errno.h>
+#include <zephyr/init.h>
+#include <zephyr/kernel.h>
+
+#define IPROC_RNG200_CTRL_OFFS       0x00
+#define IPROC_RNG200_RNG_RESET_OFFS  0x04
+#define IPROC_RNG200_RBG_RESET_OFFS  0x08
+#define IPROC_RNG200_RESERVED1_OFFS  0x0c
+#define IPROC_RNG200_RESERVED2_OFFS  0x10
+#define IPROC_RNG200_RESERVED3_OFFS  0x14
+#define IPROC_RNG200_INT_STATUS_OFFS 0x18
+#define IPROC_RNG200_RESERVED4_OFFS  0x1c
+#define IPROC_RNG200_FIFO_DATA_OFFS  0x20
+#define IPROC_RNG200_FIFO_COUNT_OFFS 0x24
+
+#define IPROC_RNG200_CTRL_RBG_EN                    BIT(0)
+#define IPROC_RNG200_RESET_EN                       BIT(0)
+#define IPROC_RNG200_INT_STATUS_NIST_FAIL           BIT(5)
+#define IPROC_RNG200_INT_STATUS_MASTER_FAIL_LOCKOUT BIT(31)
+
+#define IPROC_RNG200_CTRL_RBG_EN_MASK BIT_MASK(13)
+#define IPROC_RNG200_FIFO_COUNT_MASK  BIT_MASK(8)
+
+/* time needed to fill fifo when empty */
+#define IPROC_RNG200_FIFO_REFILL_TIME_USEC   40
+#define IPROC_RNG200_FIFO_REFILL_MAX_RETRIES 5
+
+#define DEV_CFG(dev)  ((const struct iproc_rng200_config *)(dev)->config)
+#define DEV_DATA(dev) ((struct iproc_rng200_data *)(dev)->data)
+
+struct iproc_rng200_config {
+	DEVICE_MMIO_NAMED_ROM(base_addr);
+};
+
+struct iproc_rng200_data {
+	DEVICE_MMIO_NAMED_RAM(base_addr);
+	struct k_mutex mutex;
+};
+
+static int iproc_rng200_driver_init(const struct device *dev)
+{
+	struct iproc_rng200_data *const data = dev->data;
+
+	k_mutex_init(&data->mutex);
+
+	DEVICE_MMIO_NAMED_MAP(dev, base_addr, K_MEM_CACHE_NONE);
+
+	const mem_addr_t base = DEVICE_MMIO_NAMED_GET(dev, base_addr);
+	const uint32_t val =
+		sys_read32(base + IPROC_RNG200_CTRL_OFFS) & IPROC_RNG200_CTRL_RBG_EN_MASK;
+
+	sys_write32(val & ~IPROC_RNG200_CTRL_RBG_EN, base + IPROC_RNG200_CTRL_OFFS);
+
+	return 0;
+}
+
+static int iproc_rng200_driver_get_entropy(const struct device *dev, uint8_t *buffer,
+					   uint16_t length)
+{
+	const mem_addr_t base = DEVICE_MMIO_NAMED_GET(dev, base_addr);
+	const uint32_t word_count = DIV_ROUND_UP(length, 4);
+	struct iproc_rng200_data *const data = dev->data;
+	uint32_t retries_left;
+	uint32_t random_word;
+
+	for (uint32_t i = 0; i < word_count; i++) {
+		retries_left = IPROC_RNG200_FIFO_REFILL_MAX_RETRIES;
+		k_mutex_lock(&data->mutex, K_FOREVER);
+
+		while (true) {
+			const uint32_t status = sys_read32(base + IPROC_RNG200_INT_STATUS_OFFS);
+			uint32_t val;
+
+			if (status & (IPROC_RNG200_INT_STATUS_MASTER_FAIL_LOCKOUT |
+				      IPROC_RNG200_INT_STATUS_NIST_FAIL)) {
+
+				sys_write32(0xFFFFFFFF, base + IPROC_RNG200_INT_STATUS_OFFS);
+
+				val = sys_read32(base + IPROC_RNG200_RNG_RESET_OFFS);
+				sys_write32(val | IPROC_RNG200_RESET_EN,
+					    base + IPROC_RNG200_RNG_RESET_OFFS);
+
+				val = sys_read32(base + IPROC_RNG200_RBG_RESET_OFFS);
+				sys_write32(val | IPROC_RNG200_RESET_EN,
+					    base + IPROC_RNG200_RBG_RESET_OFFS);
+
+				val = sys_read32(base + IPROC_RNG200_RNG_RESET_OFFS);
+				sys_write32(val & ~IPROC_RNG200_RESET_EN,
+					    base + IPROC_RNG200_RNG_RESET_OFFS);
+
+				val = sys_read32(base + IPROC_RNG200_RBG_RESET_OFFS);
+				sys_write32(val & ~IPROC_RNG200_RESET_EN,
+					    base + IPROC_RNG200_RBG_RESET_OFFS);
+			}
+
+			/* make sure fifo has at least one random word */
+			const uint32_t fcnt = sys_read32(base + IPROC_RNG200_FIFO_COUNT_OFFS);
+
+			if ((fcnt & IPROC_RNG200_FIFO_COUNT_MASK) > 0) {
+				/* get new random word */
+				random_word = sys_read32(base + IPROC_RNG200_FIFO_DATA_OFFS);
+				break;
+			}
+
+			/* currently no random values available, thus wait */
+			retries_left--;
+			if (!retries_left) {
+				/* number of retries exhausted, give up */
+				k_mutex_unlock(&data->mutex);
+				return -ETIMEDOUT;
+			}
+
+			k_sleep(K_USEC(IPROC_RNG200_FIFO_REFILL_TIME_USEC));
+		}
+
+		k_mutex_unlock(&data->mutex);
+
+		memcpy(&buffer[i * 4], &random_word, MIN(length, 4));
+		length -= 4;
+	}
+
+	return 0;
+}
+
+static DEVICE_API(entropy, iproc_rng200_entropy_api) = {
+	.get_entropy = iproc_rng200_driver_get_entropy,
+};
+
+#define IPROC_RNG200_INIT(n)                                                                       \
+	static const struct iproc_rng200_config iproc_rng200_##n##_cfg = {                         \
+		DEVICE_MMIO_NAMED_ROM_INIT(base_addr, DT_DRV_INST(n)),                             \
+	};                                                                                         \
+	static struct iproc_rng200_data iproc_rng200_##n##_data;                                   \
+                                                                                                   \
+	DEVICE_DT_INST_DEFINE(n, iproc_rng200_driver_init, NULL, &iproc_rng200_##n##_data,         \
+			      &iproc_rng200_##n##_cfg, PRE_KERNEL_1, CONFIG_ENTROPY_INIT_PRIORITY, \
+			      &iproc_rng200_entropy_api);
+
+DT_INST_FOREACH_STATUS_OKAY(IPROC_RNG200_INIT)

dts/arm64/broadcom/bcm2712.dtsi

@@ -52,6 +52,12 @@
 			status = "okay";
 		};
 
+		rng: rng@107d208000 {
+			compatible = "brcm,iproc-rng200";
+			reg = <0x10 0x7d208000 0x28>;
+			status = "okay";
+		};
+
 		gpio2@107d517c00 {
 			compatible = "simple-bus";
 			reg = <0x10 0x7d517c00 0x40>;

dts/bindings/rng/brcm,iproc-rng200.yaml

@@ -0,0 +1,12 @@
+# Copyright (c) 2025 TOKITA Hiroshi
+# SPDX-License-Identifier: Apache-2.0
+
+description: Broadcom iProc RNG200 Random Number Generator
+
+compatible: "brcm,iproc-rng200"
+
+include: base.yaml
+
+properties:
+  reg:
+    required: true