From ecf795f0f1230ff2b4e0442b666d5be9b2b7ee95 Mon Sep 17 00:00:00 2001
From: Ali Hozhabri <ali.hozhabri@st.com>
Date: Thu, 15 May 2025 11:26:58 +0200
Subject: [PATCH] drivers: bluetooth: hci: Use TRNG peripheral for BLE purpose
 on WB0x

Call entropy APIs to use TRNG peripheral on STM32WB0x devices for BLE
purposes.

Enable RNG node on Nucleo-WB0x boards.

Remove RNG initialization as it's done in the entropy driver.

Signed-off-by: Ali Hozhabri <ali.hozhabri@st.com>
---
 boards/st/nucleo_wb05kz/nucleo_wb05kz.dts |  5 +++++
 boards/st/nucleo_wb07cc/nucleo_wb07cc.dts |  5 +++++
 boards/st/nucleo_wb09ke/nucleo_wb09ke.dts |  5 +++++
 drivers/bluetooth/hci/hci_stm32wb0.c      | 27 +++++++++++++++++++++--
 4 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/boards/st/nucleo_wb05kz/nucleo_wb05kz.dts b/boards/st/nucleo_wb05kz/nucleo_wb05kz.dts
index fa82620367b..63c88eb0881 100644
--- a/boards/st/nucleo_wb05kz/nucleo_wb05kz.dts
+++ b/boards/st/nucleo_wb05kz/nucleo_wb05kz.dts
@@ -24,6 +24,7 @@
 		zephyr,sram = &sram0;
 		zephyr,flash = &flash0;
 		zephyr,bt-c2h-uart = &usart1;
+		zephyr,entropy = &rng;
 	};
 
 	leds: leds {
@@ -167,6 +168,10 @@
 	};
 };
 
+&rng {
+	status = "okay";
+};
+
 &flash0 {
 	partitions {
 		compatible = "fixed-partitions";
diff --git a/boards/st/nucleo_wb07cc/nucleo_wb07cc.dts b/boards/st/nucleo_wb07cc/nucleo_wb07cc.dts
index b8e411b9fca..2a967e83ced 100644
--- a/boards/st/nucleo_wb07cc/nucleo_wb07cc.dts
+++ b/boards/st/nucleo_wb07cc/nucleo_wb07cc.dts
@@ -24,6 +24,7 @@
 		zephyr,sram = &sram0;
 		zephyr,flash = &flash0;
 		zephyr,bt-c2h-uart = &usart1;
+		zephyr,entropy = &rng;
 	};
 
 	leds: leds {
@@ -164,6 +165,10 @@
 	};
 };
 
+&rng {
+	status = "okay";
+};
+
 &flash0 {
 	partitions {
 		compatible = "fixed-partitions";
diff --git a/boards/st/nucleo_wb09ke/nucleo_wb09ke.dts b/boards/st/nucleo_wb09ke/nucleo_wb09ke.dts
index 714ad30d0b3..f9b1b9e274d 100644
--- a/boards/st/nucleo_wb09ke/nucleo_wb09ke.dts
+++ b/boards/st/nucleo_wb09ke/nucleo_wb09ke.dts
@@ -24,6 +24,7 @@
 		zephyr,sram = &sram0;
 		zephyr,flash = &flash0;
 		zephyr,bt-c2h-uart = &usart1;
+		zephyr,entropy = &rng;
 	};
 
 	leds: leds {
@@ -166,6 +167,10 @@
 	};
 };
 
+&rng {
+	status = "okay";
+};
+
 &flash0 {
 	partitions {
 		compatible = "fixed-partitions";
diff --git a/drivers/bluetooth/hci/hci_stm32wb0.c b/drivers/bluetooth/hci/hci_stm32wb0.c
index 49926665d6b..e6d3e16dd32 100644
--- a/drivers/bluetooth/hci/hci_stm32wb0.c
+++ b/drivers/bluetooth/hci/hci_stm32wb0.c
@@ -10,6 +10,7 @@
 #include <zephyr/sys/byteorder.h>
 #include <zephyr/bluetooth/hci_types.h>
 #include <zephyr/drivers/bluetooth.h>
+#include <zephyr/drivers/entropy.h>
 #include "bleplat_cntr.h"
 #include "ble_stack.h"
 #include "stm32wb0x_hal_radio_timer.h"
@@ -20,7 +21,6 @@
 #include "dm_alloc.h"
 #include "aci_adv_nwk.h"
 #include "app_common.h"
-#include "hw_rng.h"
 #include "hw_aes.h"
 #include "hw_pka.h"
 
@@ -301,6 +301,30 @@ static void ble_isr_installer(void)
 	IRQ_CONNECT(PKA_IRQn, PKA_PRIO, _PKA_IRQHandler, NULL, PKA_FLAGS);
 }
 
+static void rng_get_random(void *num, size_t size)
+{
+	const struct device *dev = DEVICE_DT_GET(DT_DRV_INST(0));
+	int res;
+
+	/* try to allocate from pool */
+	res = entropy_get_entropy_isr(dev, (uint8_t *)num, size, !ENTROPY_BUSYWAIT);
+	if (res != size) {
+		/* Not enough available random numbers, so it falls back to polling */
+		entropy_get_entropy_isr(dev, (uint8_t *)num, size, ENTROPY_BUSYWAIT);
+	}
+}
+
+/* BLEPLAT_RngGetRandomXX definitions are needed for the BLE library. */
+void BLEPLAT_RngGetRandom16(uint16_t *num)
+{
+	rng_get_random(num, sizeof(*num));
+}
+
+void BLEPLAT_RngGetRandom32(uint32_t *num)
+{
+	rng_get_random(num, sizeof(*num));
+}
+
 static struct net_buf *get_rx(uint8_t *msg)
 {
 	bool discardable = false;
@@ -465,7 +489,6 @@ static int bt_hci_stm32wb0_open(const struct device *dev, bt_hci_recv_t recv)
 	HAL_RADIO_Init(&hradio);
 	HAL_RADIO_TIMER_Init(&VTIMER_InitStruct);
 
-	HW_RNG_Init();
 	HW_AES_Init();
 	hpka.Instance = PKA;
 	HAL_PKA_Init(&hpka);