dm: sandbox: pci: Add a PCI emulation uclass

Since sandbox does not have real devices (unless it borrows those from the
host) it must use emulations. Provide a uclass which permits PCI operations
to be passed through to an emulation device.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 9e2e5f9..c1c2ae3c 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -8,6 +8,7 @@
 ifneq ($(CONFIG_DM_PCI),)
 obj-$(CONFIG_PCI) += pci-uclass.o pci_compat.o
 obj-$(CONFIG_PCI_SANDBOX) += pci_sandbox.o
+obj-$(CONFIG_SANDBOX) += pci-emul-uclass.o
 else
 obj-$(CONFIG_PCI) += pci.o
 endif
diff --git a/drivers/pci/pci-emul-uclass.c b/drivers/pci/pci-emul-uclass.c
new file mode 100644
index 0000000..0f8e3c9
--- /dev/null
+++ b/drivers/pci/pci-emul-uclass.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2014 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <fdtdec.h>
+#include <libfdt.h>
+#include <pci.h>
+#include <dm/lists.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct sandbox_pci_priv {
+	int dev_count;
+};
+
+int sandbox_pci_get_emul(struct udevice *bus, pci_dev_t find_devfn,
+			 struct udevice **emulp)
+{
+	struct udevice *dev;
+	int ret;
+
+	ret = pci_bus_find_devfn(bus, find_devfn, &dev);
+	if (ret) {
+		debug("%s: Could not find emulator for dev %x\n", __func__,
+		      find_devfn);
+		return ret;
+	}
+
+	ret = device_find_first_child(dev, emulp);
+	if (ret)
+		return ret;
+
+	return *emulp ? 0 : -ENODEV;
+}
+
+static int sandbox_pci_emul_post_probe(struct udevice *dev)
+{
+	struct sandbox_pci_priv *priv = dev->uclass->priv;
+
+	priv->dev_count++;
+	sandbox_set_enable_pci_map(true);
+
+	return 0;
+}
+
+static int sandbox_pci_emul_pre_remove(struct udevice *dev)
+{
+	struct sandbox_pci_priv *priv = dev->uclass->priv;
+
+	priv->dev_count--;
+	sandbox_set_enable_pci_map(priv->dev_count > 0);
+
+	return 0;
+}
+
+UCLASS_DRIVER(pci_emul) = {
+	.id		= UCLASS_PCI_EMUL,
+	.name		= "pci_emul",
+	.post_probe	= sandbox_pci_emul_post_probe,
+	.pre_remove	= sandbox_pci_emul_pre_remove,
+	.priv_auto_alloc_size	= sizeof(struct sandbox_pci_priv),
+};