chip/host: Add spi+trng support, and add gpio func

This adds fake SPI Master and TRNG support to the
host target.
This change also adds the missing emulated gpio
interface function.

Although general purpose, these changes are setup for
allowing fuzzing of the FPMCU specific host commands.
Thus, they do not impact any outstanding code.

BRANCH=none
BUG=b:116065496
TEST=make buildall -j

Change-Id: Icfc40e7bf8ee421a4c3ad15377fd56ae68c763d7
Signed-off-by: Craig Hesling <hesling@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1684223
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/chip/host/trng.c b/chip/host/trng.c
new file mode 100644
index 0000000000..e27dc9d607
--- /dev/null
+++ b/chip/host/trng.c
@@ -0,0 +1,36 @@
+
+/* Copyright 2019 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Dummy TRNG driver for unit test.
+ *
+ * Although a TRNG is designed to be anything but predictable,
+ * this implementation strives to be as predictable and defined
+ * as possible to allow reproducing unit tests and fuzzer crashes.
+ */
+
+#include <stdint.h>
+#include <stdlib.h> /* Only valid for host */
+
+#include "common.h"
+
+static unsigned int seed;
+
+test_mockable void init_trng(void)
+{
+	seed = 0;
+	srand(seed);
+}
+
+test_mockable void exit_trng(void)
+{
+}
+
+test_mockable void rand_bytes(void *buffer, size_t len)
+{
+	uint8_t *b, *end;
+
+	for (b = buffer, end = b+len; b != end; b++)
+		*b = (uint8_t)rand_r(&seed);
+}