sandbox: Add PCI driver and test for p2sb

Add a sandbox driver and PCI-device emulator for p2sb. Also add a test
which uses a simple 'adder' driver to test the p2sb functionality.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/test/dm/p2sb.c b/test/dm/p2sb.c
new file mode 100644
index 0000000..ccb75cf
--- /dev/null
+++ b/test/dm/p2sb.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Test for Primary-to-Sideband bus (P2SB)
+ *
+ * Copyright 2019 Google LLC
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <p2sb.h>
+#include <asm/test.h>
+#include <dm/test.h>
+#include <test/ut.h>
+
+/* Base test of the PMC uclass */
+static int dm_test_p2sb_base(struct unit_test_state *uts)
+{
+	struct udevice *dev;
+
+	sandbox_set_enable_memio(true);
+	ut_assertok(uclass_get_device_by_name(UCLASS_AXI, "adder", &dev));
+	ut_asserteq(0x03000004, pcr_read32(dev, 4));
+	ut_asserteq(0x300, pcr_read16(dev, 6));
+	ut_asserteq(4, pcr_read8(dev, 4));
+
+	return 0;
+}
+DM_TEST(dm_test_p2sb_base, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);