From 3f0522ce8f818e3e777279b8f7c55abc694954a3 Mon Sep 17 00:00:00 2001
From: Joseph Chen <chenjh@rock-chips.com>
Date: Fri, 29 Jan 2021 20:06:29 +0800
Subject: [PATCH] rng: rockchip: add hardware rand library

Signed-off-by: Joseph Chen <chenjh@rock-chips.com>
Change-Id: Id22c5725158d86cc8a2ff80fdf09b0146d04be41
---
 drivers/rng/Makefile        |  5 +++++
 drivers/rng/rockchip_rand.c | 40 +++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 drivers/rng/rockchip_rand.c

diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
index 471cf5d6a4..58cee3a56e 100644
--- a/drivers/rng/Makefile
+++ b/drivers/rng/Makefile
@@ -5,3 +5,8 @@
 
 obj-$(CONFIG_DM_RNG) += rng-uclass.o
 obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rng.o
+
+ifdef CONFIG_LIB_HW_RAND
+obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rand.o
+endif
+
diff --git a/drivers/rng/rockchip_rand.c b/drivers/rng/rockchip_rand.c
new file mode 100644
index 0000000000..e8bac8f629
--- /dev/null
+++ b/drivers/rng/rockchip_rand.c
@@ -0,0 +1,40 @@
+/*
+ * (C) Copyright 2021 Rockchip Electronics Co., Ltd
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+#include <common.h>
+#include <dm.h>
+#include <rng.h>
+
+unsigned int rand_r(unsigned int *seedp)
+{
+	struct udevice *dev;
+	unsigned int rand;
+	int ret;
+
+	ret = uclass_get_device(UCLASS_RNG, 0, &dev);
+	if (ret) {
+		printf("No RNG device, ret=%d\n", ret);
+		return ret;
+	}
+
+	ret = dm_rng_read(dev, &rand, sizeof(unsigned int));
+	if (ret) {
+		printf("Reading RNG failed, ret=%d\n", ret);
+		return ret;
+	}
+
+	return rand;
+}
+
+unsigned int rand(void)
+{
+	return rand_r(0);
+}
+
+void srand(unsigned int seed)
+{
+	/* nothing to do */
+}
+