From 3e4e9496a1b6ad00a2a9526040d8a570068499b0 Mon Sep 17 00:00:00 2001
From: Yuriy Vynnychek <yura.vynnychek@telink-semi.com>
Date: Mon, 26 Jul 2021 11:27:10 +0300
Subject: [PATCH] drivers: entropy: introduce new Telink B91 Entropy driver

Entropy driver basic support for new Telink B91 platform.

Signed-off-by: Yuriy Vynnychek <yura.vynnychek@telink-semi.com>
---
 CODEOWNERS                         |  1 +
 drivers/entropy/CMakeLists.txt     |  1 +
 drivers/entropy/Kconfig            |  1 +
 drivers/entropy/Kconfig.b91        | 11 +++++
 drivers/entropy/entropy_b91_trng.c | 71 ++++++++++++++++++++++++++++++
 5 files changed, 85 insertions(+)
 create mode 100644 drivers/entropy/Kconfig.b91
 create mode 100644 drivers/entropy/entropy_b91_trng.c

diff --git a/CODEOWNERS b/CODEOWNERS
index 50cb2f78984..dc8c93fdd1d 100644
--- a/CODEOWNERS
+++ b/CODEOWNERS
@@ -211,6 +211,7 @@
 /drivers/edac/                            @finikorg
 /drivers/eeprom/                          @henrikbrixandersen
 /drivers/eeprom/eeprom_stm32.c            @KwonTae-young
+/drivers/entropy/*b91*                    @yurvyn
 /drivers/entropy/*rv32m1*                 @MaureenHelm
 /drivers/entropy/*gecko*                  @chrta
 /drivers/entropy/*litex*                  @mateusz-holenko @kgugala @pgielda
diff --git a/drivers/entropy/CMakeLists.txt b/drivers/entropy/CMakeLists.txt
index 3d643b5d0d3..526a91a9b4b 100644
--- a/drivers/entropy/CMakeLists.txt
+++ b/drivers/entropy/CMakeLists.txt
@@ -2,6 +2,7 @@
 
 zephyr_library()
 
+zephyr_library_sources_ifdef(CONFIG_ENTROPY_TELINK_B91_TRNG    entropy_b91_trng.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)
 zephyr_library_sources_ifdef(CONFIG_ENTROPY_MCUX_RNG          entropy_mcux_rng.c)
diff --git a/drivers/entropy/Kconfig b/drivers/entropy/Kconfig
index 199257c7888..e73945b921a 100644
--- a/drivers/entropy/Kconfig
+++ b/drivers/entropy/Kconfig
@@ -10,6 +10,7 @@ menuconfig ENTROPY_GENERATOR
 
 if ENTROPY_GENERATOR
 
+source "drivers/entropy/Kconfig.b91"
 source "drivers/entropy/Kconfig.cc13xx_cc26xx"
 source "drivers/entropy/Kconfig.mcux"
 source "drivers/entropy/Kconfig.stm32"
diff --git a/drivers/entropy/Kconfig.b91 b/drivers/entropy/Kconfig.b91
new file mode 100644
index 00000000000..e59ad1ffb56
--- /dev/null
+++ b/drivers/entropy/Kconfig.b91
@@ -0,0 +1,11 @@
+# Copyright (c) 2021 Telink Semiconductor
+# SPDX-License-Identifier: Apache-2.0
+
+# Telink B91 GPIO configuration options
+
+config ENTROPY_TELINK_B91_TRNG
+	bool "Telink B91 Entropy driver"
+	depends on SOC_RISCV_TELINK_B91
+	select ENTROPY_HAS_DRIVER
+	help
+	  Enable the B91 Entropy driver.
diff --git a/drivers/entropy/entropy_b91_trng.c b/drivers/entropy/entropy_b91_trng.c
new file mode 100644
index 00000000000..20cacea6436
--- /dev/null
+++ b/drivers/entropy/entropy_b91_trng.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2021 Telink Semiconductor
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT telink_b91_trng
+
+#include <trng.h>
+#include <drivers/entropy.h>
+#include <string.h>
+
+
+/* API implementation: driver initialization */
+static int entropy_b91_trng_init(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+
+	trng_init();
+
+	return 0;
+}
+
+/* API implementation: get_entropy */
+static int entropy_b91_trng_get_entropy(const struct device *dev,
+					uint8_t *buffer, uint16_t length)
+{
+	ARG_UNUSED(dev);
+
+	uint32_t value = 0;
+
+	while (length) {
+		value = trng_rand();
+
+		if (length >= sizeof(value)) {
+			memcpy(buffer, &value, sizeof(value));
+			buffer += sizeof(value);
+			length -= sizeof(value);
+		} else {
+			memcpy(buffer, &value, length);
+			break;
+		}
+	}
+
+	return 0;
+}
+
+/* API implementation: get_entropy_isr */
+static int entropy_b91_trng_get_entropy_isr(const struct device *dev,
+					    uint8_t *buffer, uint16_t length,
+					    uint32_t flags)
+{
+	ARG_UNUSED(flags);
+
+	/* No specific handling in case of running from ISR, just call standard API */
+	entropy_b91_trng_get_entropy(dev, buffer, length);
+
+	return 0;
+}
+
+/* Entropy driver APIs structure */
+static const struct entropy_driver_api entropy_b91_trng_api = {
+	.get_entropy = entropy_b91_trng_get_entropy,
+	.get_entropy_isr = entropy_b91_trng_get_entropy_isr
+};
+
+/* Entropy driver registration */
+DEVICE_DT_INST_DEFINE(0, entropy_b91_trng_init,
+		      NULL, NULL, NULL,
+		      PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
+		      &entropy_b91_trng_api);