[PATCH v3] arm64: zynqmp: Enable rng-seed generation

[Michal Simek]

SOM has TPM with RNG in it that's why enable rng-seed generation.

Signed-off-by: Michal Simek <michal.simek at amd.com>
---

Changes in v3:
- Move malloc allocation before rng_read

Changes in v2:
- Free alloc area in case of error

 board/xilinx/common/board.c          | 33 +++++++++++++++++++++++++++-
 configs/xilinx_zynqmp_kria_defconfig |  1 +
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/board/xilinx/common/board.c b/board/xilinx/common/board.c
index 8ffe74299016..ceb58da6d3cd 100644
--- a/board/xilinx/common/board.c
+++ b/board/xilinx/common/board.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2014 - 2022, Xilinx, Inc.
- * (C) Copyright 2022 - 2023, Advanced Micro Devices, Inc.
+ * (C) Copyright 2022 - 2025, Advanced Micro Devices, Inc.
  *
  * Michal Simek <michal.simek at amd.com>
  */
@@ -712,3 +712,34 @@ phys_addr_t board_get_usable_ram_top(phys_size_t total_size)
 }
 
 #endif
+
+#if IS_ENABLED(CONFIG_BOARD_RNG_SEED)
+/* Use hardware rng to seed Linux random. */
+__weak int board_rng_seed(struct abuf *buf)
+{
+	struct udevice *dev;
+	ulong len = 64;
+	u64 *data;
+
+	if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) {
+		printf("No RNG device\n");
+		return -ENODEV;
+	}
+
+	data = malloc(len);
+	if (!data) {
+		printf("Out of memory\n");
+		return -ENOMEM;
+	}
+
+	if (dm_rng_read(dev, data, len)) {
+		printf("Reading RNG failed\n");
+		free(data);
+		return -EIO;
+	}
+
+	abuf_init_set(buf, data, len);
+
+	return 0;
+}
+#endif
diff --git a/configs/xilinx_zynqmp_kria_defconfig b/configs/xilinx_zynqmp_kria_defconfig
index 22ba8a7cc158..3e2ac6144050 100644
--- a/configs/xilinx_zynqmp_kria_defconfig
+++ b/configs/xilinx_zynqmp_kria_defconfig
@@ -46,6 +46,7 @@ CONFIG_USE_PREBOOT=y
 CONFIG_SYS_PBSIZE=2073
 CONFIG_BOARD_EARLY_INIT_R=y
 CONFIG_CLOCKS=y
+CONFIG_BOARD_RNG_SEED=y
 CONFIG_SPL_MAX_SIZE=0x40000
 # CONFIG_SPL_BINMAN_SYMBOLS is not set
 # CONFIG_SPL_SHARES_INIT_SP_ADDR is not set
-- 
2.43.0

base-commit: 506757335edcf5e74eac0e608f1835a8b0102c4b
branch: debian-sent3