drivers: entropy: Add the PSA Crypto Random entropy driver

This adds an entropy driver calling the PSA Crypto psa_generate_random() API to get random bytes. Currently this only uses the TFM provided psa_generate_random(). Signed-off-by: Neil Armstrong <[email protected]> Signed-off-by: Valerio Setti <[email protected]>
albayenes · Oct 27, 2022 · 3b407a1 · 3b407a1
1 parent e1429d7
commit 3b407a1
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diff --git a/drivers/entropy/CMakeLists.txt b/drivers/entropy/CMakeLists.txt
@@ -20,3 +20,10 @@ zephyr_library_sources_ifdef(CONFIG_ENTROPY_GECKO_TRNG         entropy_gecko_trn
 zephyr_library_sources_ifdef(CONFIG_ENTROPY_NEORV32_TRNG       entropy_neorv32_trng.c)
 zephyr_library_sources_ifdef(CONFIG_ENTROPY_BT_HCI             entropy_bt_hci.c)
 zephyr_library_sources_ifdef(CONFIG_ENTROPY_GECKO_SE           entropy_gecko_se.c)
+zephyr_library_sources_ifdef(CONFIG_ENTROPY_PSA_CRYPTO_RNG     entropy_psa_crypto.c)
+
+if (CONFIG_BUILD_WITH_TFM)
+  target_include_directories(${ZEPHYR_CURRENT_LIBRARY} PRIVATE
+    $<TARGET_PROPERTY:tfm,TFM_BINARY_DIR>/install/interface/include
+  )
+endif()
diff --git a/drivers/entropy/Kconfig b/drivers/entropy/Kconfig
@@ -33,6 +33,7 @@ source "drivers/entropy/Kconfig.litex"
 source "drivers/entropy/Kconfig.gecko"
 source "drivers/entropy/Kconfig.neorv32"
 source "drivers/entropy/Kconfig.bt_hci"
+source "drivers/entropy/Kconfig.psa_crypto"
 
 config ENTROPY_HAS_DRIVER
 	bool

diff --git a/drivers/entropy/Kconfig.psa_crypto b/drivers/entropy/Kconfig.psa_crypto
@@ -0,0 +1,11 @@
+# Copyright (c) 2022 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+# PSA Crypto Random source configuration options
+
+config ENTROPY_PSA_CRYPTO_RNG
+	bool "PSA Crypto Random source Entropy driver"
+	depends on BUILD_WITH_TFM
+	select ENTROPY_HAS_DRIVER
+	help
+	  Enable the PSA Crypto source Entropy driver.
diff --git a/drivers/entropy/entropy_psa_crypto.c b/drivers/entropy/entropy_psa_crypto.c
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2022 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT zephyr_psa_crypto_rng
+
+#include <zephyr/drivers/entropy.h>
+#include <psa/crypto.h>
+
+/* API implementation: PSA Crypto initialization */
+static int entropy_psa_crypto_rng_init(const struct device *dev)
+{
+	psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+
+	ARG_UNUSED(dev);
+
+	status = psa_crypto_init();
+	if (status != PSA_SUCCESS) {
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/* API implementation: get_entropy */
+static int entropy_psa_crypto_rng_get_entropy(const struct device *dev,
+					      uint8_t *buffer, uint16_t length)
+{
+	psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+
+	ARG_UNUSED(dev);
+
+	status = psa_generate_random(buffer, length);
+	if (status != PSA_SUCCESS) {
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/* Entropy driver APIs structure */
+static const struct entropy_driver_api entropy_psa_crypto_rng_api = {
+	.get_entropy = entropy_psa_crypto_rng_get_entropy,
+};
+
+/* Entropy driver registration */
+DEVICE_DT_INST_DEFINE(0, entropy_psa_crypto_rng_init, NULL, NULL, NULL,
+		      PRE_KERNEL_1, CONFIG_ENTROPY_INIT_PRIORITY,
+		      &entropy_psa_crypto_rng_api);