From 8f0235fb8f2d46ee6ca6309f8c365ad57e3a1565 Mon Sep 17 00:00:00 2001
From: Leo Yan <leo.yan@arm.com>
Date: Fri, 31 Jan 2025 10:20:28 +0000
Subject: [PATCH] feat(tc): get entropy with PSA Crypto API

The PSA Crypto API is available with sending messages to RSE.  Change
to invoke PSA Crypto API for getting entropy.

Change-Id: I4b2dc4eb99606c2425b64949d9c3f5c576883758
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Icen Zeyada <Icen.Zeyada2@arm.com>
---
 plat/arm/board/tc/platform.mk |  3 ++-
 plat/arm/board/tc/tc_trng.c   | 20 +++++++++++++++++---
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/plat/arm/board/tc/platform.mk b/plat/arm/board/tc/platform.mk
index 8b15a6f23..21d712221 100644
--- a/plat/arm/board/tc/platform.mk
+++ b/plat/arm/board/tc/platform.mk
@@ -248,7 +248,8 @@ include drivers/arm/rse/rse_comms.mk
 
 BL1_SOURCES	+=	${RSE_COMMS_SOURCES}
 BL2_SOURCES	+=	${RSE_COMMS_SOURCES}
-BL31_SOURCES	+=	${RSE_COMMS_SOURCES}
+BL31_SOURCES	+=	${RSE_COMMS_SOURCES} \
+			lib/psa/rse_platform.c
 
 # Include Measured Boot makefile before any Crypto library makefile.
 # Crypto library makefile may need default definitions of Measured Boot build
diff --git a/plat/arm/board/tc/tc_trng.c b/plat/arm/board/tc/tc_trng.c
index e5ec48a1a..793a90fbc 100644
--- a/plat/arm/board/tc/tc_trng.c
+++ b/plat/arm/board/tc/tc_trng.c
@@ -11,6 +11,7 @@
 #include <string.h>
 
 #include <lib/mmio.h>
+#include <lib/psa/rse_platform_api.h>
 #include <lib/smccc.h>
 #include <lib/utils_def.h>
 #include <plat/common/platform.h>
@@ -24,20 +25,33 @@ DEFINE_SVC_UUID2(_plat_trng_uuid,
 );
 uuid_t plat_trng_uuid;
 
-/* Dummy implementation */
 bool plat_get_entropy(uint64_t *out)
 {
+#if CRYPTO_SUPPORT
+	psa_status_t status;
+
+	status = rse_platform_get_entropy((uint8_t *)out, sizeof(*out));
+	if (status != PSA_SUCCESS) {
+		printf("Failed for entropy read, psa_status=%d\n", status);
+		return false;
+	}
+#else
+	/* Dummy value */
 	*out = 0xABBAEDDAACDCDEAD;
+#endif
 
 	return true;
 }
 
 void plat_entropy_setup(void)
 {
-	uint64_t dummy;
+	uint64_t entropy;
 
 	plat_trng_uuid = _plat_trng_uuid;
 
 	/* Initialise the entropy source and trigger RNG generation */
-	plat_get_entropy(&dummy);
+	if (!plat_get_entropy(&entropy)) {
+		ERROR("Failed to setup entropy\n");
+		panic();
+	}
 }