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/drivers/misc/p2sb_sandbox.c b/drivers/misc/p2sb_sandbox.c
new file mode 100644
index 0000000..ce50a97
--- /dev/null
+++ b/drivers/misc/p2sb_sandbox.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sandbox P2SB for testing
+ *
+ * Copyright 2019 Google LLC
+ */
+
+#define LOG_CATEGORY UCLASS_P2SB
+
+#include <common.h>
+#include <dm.h>
+#include <asm/io.h>
+#include <p2sb.h>
+
+struct sandbox_p2sb_priv {
+	ulong base;
+};
+
+static int sandbox_p2sb_probe(struct udevice *dev)
+{
+	struct p2sb_uc_priv *upriv = dev_get_uclass_priv(dev);
+
+	upriv->mmio_base = dm_pci_read_bar32(dev, 0);
+
+	return 0;
+}
+
+static const struct udevice_id sandbox_p2sb_ids[] = {
+	{ .compatible = "sandbox,p2sb" },
+	{ }
+};
+
+U_BOOT_DRIVER(p2sb_sandbox) = {
+	.name = "p2sb_sandbox",
+	.id = UCLASS_P2SB,
+	.of_match = sandbox_p2sb_ids,
+	.probe = sandbox_p2sb_probe,
+	.priv_auto_alloc_size = sizeof(struct sandbox_p2sb_priv),
+};