drivers: entropy: Initial support for trng driver of RA8

Initial commit for entropy support on RA8
- drivers: entropy: implementation for TRNG driver of RA8x1
- dts: arm: add device node for trng of RA8x1
- boards: arm: enable support zephyr_entropy for ek_ra8m1 and
update board documentation

Signed-off-by: The Nguyen <the.nguyen.yf@renesas.com>
Signed-off-by: Duy Phuong Hoang. Nguyen <duy.nguyen.xa@renesas.com>

boards/renesas/ek_ra8m1/doc/index.rst

@@ -100,6 +100,8 @@ The below features are currently supported on Zephyr OS for EK-RA8M1 board:
 +-----------+------------+----------------------+
 | I2C       | on-chip    | i2c                  |
 +-----------+------------+----------------------+
+| ENTROPY   | on-chip    | entropy              |
++-----------+------------+----------------------+
 
 Other hardware features are currently not supported by the port.
 

boards/renesas/ek_ra8m1/ek_ra8m1.dts

@@ -19,6 +19,7 @@
 		zephyr,flash = &flash0;
 		zephyr,console = &uart9;
 		zephyr,shell-uart = &uart9;
+		zephyr,entropy = &trng;
 	};
 
 	leds {
@@ -158,3 +159,7 @@ mikrobus_serial: &uart3 {};
 	pinctrl-0 = <&adc0_default>;
 	pinctrl-names = "default";
 };
+
+&trng {
+	status = "okay";
+};

drivers/entropy/CMakeLists.txt

@@ -34,5 +34,6 @@ zephyr_library_sources_ifdef(CONFIG_ENTROPY_GECKO_SE           entropy_gecko_se.
 zephyr_library_sources_ifdef(CONFIG_ENTROPY_PSA_CRYPTO_RNG            entropy_psa_crypto.c)
 zephyr_library_sources_ifdef(CONFIG_ENTROPY_NPCX_DRBG                 entropy_npcx_drbg.c)
 zephyr_library_sources_ifdef(CONFIG_ENTROPY_MAX32_TRNG                entropy_max32.c)
+zephyr_library_sources_ifdef(CONFIG_ENTROPY_RENESAS_RA_RSIP_E51A_TRNG entropy_renesas_ra.c)
 
 zephyr_library_link_libraries_ifdef(CONFIG_BUILD_WITH_TFM tfm_api)

drivers/entropy/Kconfig

@@ -37,6 +37,7 @@ source "drivers/entropy/Kconfig.bt_hci"
 source "drivers/entropy/Kconfig.psa_crypto"
 source "drivers/entropy/Kconfig.npcx"
 source "drivers/entropy/Kconfig.max32"
+source "drivers/entropy/Kconfig.renesas_ra"
 
 config ENTROPY_HAS_DRIVER
 	bool

drivers/entropy/Kconfig.renesas_ra

@@ -0,0 +1,13 @@
+# Copyright (c) 2024 Renesas Electronics Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+# Renesas RA entropy generator driver configuration
+
+config ENTROPY_RENESAS_RA_RSIP_E51A_TRNG
+	bool "Renesas RA RSIP-E51A TRNG driver"
+	default y
+	depends on DT_HAS_RENESAS_RA_RSIP_E51A_TRNG_ENABLED
+	select ENTROPY_HAS_DRIVER
+	select USE_RA_FSP_SCE
+	help
+	  This option enables the Renesas RA RSIP-E51A RNG.

drivers/entropy/entropy_renesas_ra.c

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2024 Renesas Electronics Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT renesas_ra_rsip_e51a_trng
+
+#include <soc.h>
+#include <zephyr/drivers/entropy.h>
+
+#include "hw_sce_trng_private.h"
+#include "hw_sce_private.h"
+
+static int entropy_ra_rsip_trng_get_entropy(const struct device *dev, uint8_t *buf, uint16_t len)
+{
+	ARG_UNUSED(dev);
+
+	if (buf == NULL) {
+		return -EINVAL;
+	}
+
+	while (len > 0) {
+		uint32_t n[4];
+		const uint32_t to_copy = MIN(sizeof(n), len);
+
+		if (FSP_SUCCESS != HW_SCE_RNG_Read(n)) {
+			return -ENODATA;
+		}
+		memcpy(buf, n, to_copy);
+		buf += to_copy;
+		len -= to_copy;
+	}
+
+	return 0;
+}
+
+static const struct entropy_driver_api entropy_ra_rsip_trng_api = {
+	.get_entropy = entropy_ra_rsip_trng_get_entropy,
+};
+
+static int entropy_ra_rsip_trng_init(const struct device *dev)
+{
+	HW_SCE_McuSpecificInit();
+	return 0;
+}
+
+DEVICE_DT_INST_DEFINE(0, entropy_ra_rsip_trng_init, NULL, NULL, NULL, PRE_KERNEL_1,
+		      CONFIG_ENTROPY_INIT_PRIORITY, &entropy_ra_rsip_trng_api);

dts/arm/renesas/ra/ra8/ra8x1.dtsi

@@ -299,6 +299,10 @@
 			status = "disabled";
 		};
 
+		trng: trng {
+			compatible = "renesas,ra-rsip-e51a-trng";
+		};
+
 		option_setting_ofs: option_setting_ofs@300a100 {
 			compatible = "zephyr,memory-region";
 			reg = <0x0300a100 0x18>;

dts/bindings/rng/renesas,ra-rsip-e51a-trng.yaml

@@ -0,0 +1,8 @@
+# Copyright (c) 2024 Renesas Electronics Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+description: Renesas RA RSIP-E51A TRNG
+
+compatible: "renesas,ra-rsip-e51a-trng"
+
+include: base.yaml

modules/Kconfig.renesas_fsp

@@ -32,3 +32,19 @@ config USE_RA_FSP_ADC
 	bool
 	help
 	  Enable RA FSP ADC driver
+
+config USE_RA_FSP_SCE
+	bool
+	help
+	  Enable RA FSP SCE driver
+
+if USE_RA_FSP_SCE
+
+config HAS_RENESAS_RA_RSIP_E51A
+	bool
+	default y
+	depends on ENTROPY_RENESAS_RA_RSIP_E51A_TRNG
+	help
+	  Includes RSIP-E51A implementation for SCE driver
+
+endif