rockchip: board: Add board_rng_seed() for all Rockchip devices

Allow all rockchip devices to use the hardware RNG to seed Linux
RNG.

Signed-off-by: Chris Morgan <[email protected]>
Reviewed-by: Kever Yang <[email protected]>

1 files changed, 32 insertions, 0 deletions

diff --git a/arch/arm/mach-rockchip/board.c b/arch/arm/mach-rockchip/board.c
index 38a2a4b95ec..c1cfe0ea1d2 100644
--- a/arch/arm/mach-rockchip/board.c
+++ b/arch/arm/mach-rockchip/board.c
@@ -320,3 +320,35 @@ __weak int misc_init_r(void)
 	return ret;
 }
 #endif
+
+#if IS_ENABLED(CONFIG_BOARD_RNG_SEED) && IS_ENABLED(CONFIG_RNG_ROCKCHIP)
+#include <rng.h>
+
+/* Use hardware rng to seed Linux random. */
+__weak int board_rng_seed(struct abuf *buf)
+{
+	struct udevice *dev;
+	size_t len = 0x8;
+	u64 *data;
+
+	data = malloc(len);
+	if (!data) {
+		printf("Out of memory\n");
+		return -ENOMEM;
+	}
+
+	if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) {
+		printf("No RNG device\n");
+		return -ENODEV;
+	}
+
+	if (dm_rng_read(dev, data, len)) {
+		printf("Reading RNG failed\n");
+		return -EIO;
+	}
+
+	abuf_init_set(buf, data, len);
+
+	return 0;
+}
+#endif