tests: Add unit test to run init/shutdown for mec1308.c, ene_lpc.c

This patch includes mocks for io operations in hwaccess_x86_io.h
because those are needed to test lifecycle of mec1308.c and
ene_lpc.c

BUG=b:181803212
TEST=builds and ninja test

Change-Id: I3af612defe1af3850dfc1626a208d873e3a3eddc
Signed-off-by: Anastasia Klimchuk <aklm@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/51487
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/hwaccess_x86_io_unittest.h b/hwaccess_x86_io_unittest.h
new file mode 100644
index 0000000..7bffc96
--- /dev/null
+++ b/hwaccess_x86_io_unittest.h
@@ -0,0 +1,52 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright 2021 Google LLC
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+/*
+ * This header is used instead of hwaccess_x86_io.h for unit tests
+ * (see flashrom_test_dep in meson.build).
+ *
+ * There is no hardware in unit test environment and all hardware operations
+ * need to be mocked.
+ */
+
+/*
+ * The same guard is used intentionally for hwaccess_x86_io.h and
+ * hwaccess_x86_io_unittest.h. When build is made for the test environment,
+ * hwaccess_x86_io_unittest.h is included first, and it effectively
+ * replaces hwaccess_x86_io.h.
+ */
+#ifndef __HWACCESS_X86_IO_H__
+#define __HWACCESS_X86_IO_H__ 1
+
+#define OUTB(v, p) test_outb(v, p)
+#define OUTW(v, p) test_outw(v, p)
+#define OUTL(v, p) test_outl(v, p)
+#define INB(p) test_inb(p)
+#define INW(p) test_inw(p)
+#define INL(p) test_inl(p)
+
+#include <stdint.h>
+#include <sys/io.h>
+
+/* All functions below are mocked in unit tests. */
+
+void test_outb(uint8_t value, uint16_t port);
+uint8_t test_inb(uint16_t port);
+void test_outw(uint16_t value, uint16_t port);
+uint16_t test_inw(uint16_t port);
+void test_outl(uint32_t value, uint16_t port);
+uint32_t test_inl(uint16_t port);
+
+#endif /* !__HWACCESS_X86_IO_H__ */