random: add MCUX TRNG driver

Provide a random driver wrapped around the MCUX TRNG driver.

Change-Id: Icbd7ab587aa18ecbd7eae52290aaa5d8ee504cf2
Origin: Original
Signed-off-by: Bogdan Davidoaia <bogdan.davidoaia@linaro.org>

arch/arm/soc/nxp_kinetis/Kconfig

@@ -45,6 +45,12 @@ config HAS_RNGA
 	help
 	Set if the random number generator accelerator (RNGA) module is present in the SoC.
 
+config HAS_TRNG
+	bool
+	default n
+	help
+	Set if the true random number generator (TRNG) module is present in the SoC.
+
 config HAS_LPUART
 	bool
 	default n

drivers/random/Kconfig.mcux

@@ -12,3 +12,12 @@ menuconfig RANDOM_MCUX_RNGA
 	help
 	  This option enables the random number generator accelerator (RNGA)
 	  driver based on the MCUX RNGA driver.
+
+menuconfig RANDOM_MCUX_TRNG
+	bool "MCUX TRNG driver"
+	depends on RANDOM_GENERATOR && HAS_TRNG
+	default n
+	select RANDOM_HAS_DRIVER
+	help
+	  This option enables the true random number generator (TRNG)
+	  driver based on the MCUX TRNG driver.

drivers/random/Makefile

@@ -1,3 +1,4 @@
 obj-$(CONFIG_RANDOM_MCUX_RNGA) += random_mcux_rnga.o
+obj-$(CONFIG_RANDOM_MCUX_TRNG) += random_mcux_trng.o
 obj-$(CONFIG_TIMER_RANDOM_GENERATOR) = rand32_timer.o
 obj-$(CONFIG_X86_TSC_RANDOM_GENERATOR) += rand32_timestamp.o

drivers/random/random_mcux_trng.c

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2017 Linaro Limited.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <device.h>
+#include <random.h>
+#include <drivers/rand32.h>
+#include <init.h>
+
+#include "fsl_trng.h"
+
+static int random_mcux_trng_get_entropy(struct device *dev, uint8_t *buffer,
+					uint16_t length)
+{
+	status_t status;
+
+	ARG_UNUSED(dev);
+
+	status = TRNG_GetRandomData(TRNG0, buffer, length);
+	__ASSERT_NO_MSG(!status);
+
+	return 0;
+}
+
+static const struct random_driver_api random_mcux_trng_api_funcs = {
+	.get_entropy = random_mcux_trng_get_entropy
+};
+
+static int random_mcux_trng_init(struct device *);
+
+DEVICE_AND_API_INIT(random_mcux_trng, CONFIG_RANDOM_NAME,
+		    random_mcux_trng_init, NULL, NULL,
+		    PRE_KERNEL_2, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
+		    &random_mcux_trng_api_funcs);
+
+static int random_mcux_trng_init(struct device *dev)
+{
+	trng_config_t conf;
+	status_t status;
+
+	ARG_UNUSED(dev);
+
+	status = TRNG_GetDefaultConfig(&conf);
+	__ASSERT_NO_MSG(!status);
+
+	status = TRNG_Init(TRNG0, &conf);
+	__ASSERT_NO_MSG(!status);
+
+	return 0;
+}
+
+uint32_t sys_rand32_get(void)
+{
+	uint32_t output;
+	int rc;
+
+	rc = random_mcux_trng_get_entropy(DEVICE_GET(random_mcux_trng),
+					  (uint8_t *) &output, sizeof(output));
+	__ASSERT_NO_MSG(!rc);
+
+	return output;
+}

ext/hal/nxp/mcux/drivers/Makefile

@@ -7,6 +7,7 @@
 obj-$(CONFIG_ETH_MCUX) += fsl_enet.o
 obj-$(CONFIG_I2C_MCUX) += fsl_i2c.o
 obj-$(CONFIG_RANDOM_MCUX_RNGA) += fsl_rnga.o
+obj-$(CONFIG_RANDOM_MCUX_TRNG) += fsl_trng.o
 obj-$(CONFIG_SOC_FLASH_MCUX) += fsl_flash.o
 obj-$(CONFIG_SPI_MCUX) += fsl_dspi.o
 obj-$(CONFIG_UART_MCUX) += fsl_uart.o