dm: sandbox: Add a simple PCI driver

Add a driver which can access emulations of devices and make them available
in sandbox.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/pci/Kconfig

@@ -9,4 +9,14 @@ config DM_PCI
 	  available PCI devices, allows scanning of PCI buses and provides
 	  device configuration support.
 
+config PCI_SANDBOX
+	bool "Sandbox PCI support"
+	depends on SANDBOX && DM_PCI
+	help
+	  Support PCI on sandbox, as an emulated bus. This permits testing of
+	  PCI feature such as bus scanning, device configuration and device
+	  access. The available (emulated) devices are defined statically in
+	  the device tree but the normal PCI scan technique is used to find
+	  then.
+
 endmenu

drivers/pci/Makefile

@@ -7,6 +7,7 @@
 
 ifneq ($(CONFIG_DM_PCI),)
 obj-$(CONFIG_PCI) += pci-uclass.o pci_compat.o
+obj-$(CONFIG_PCI_SANDBOX) += pci_sandbox.o
 else
 obj-$(CONFIG_PCI) += pci.o
 endif

drivers/pci/pci_sandbox.c

@@ -0,0 +1,79 @@
+/*
+ * 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 <inttypes.h>
+#include <pci.h>
+#include <dm/root.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int sandbox_pci_write_config(struct udevice *bus, pci_dev_t devfn,
+				    uint offset, ulong value,
+				    enum pci_size_t size)
+{
+	struct dm_pci_emul_ops *ops;
+	struct udevice *emul;
+	int ret;
+
+	ret = sandbox_pci_get_emul(bus, devfn, &emul);
+	if (ret)
+		return ret == -ENODEV ? 0 : ret;
+	ops = pci_get_emul_ops(emul);
+	if (!ops || !ops->write_config)
+		return -ENOSYS;
+
+	return ops->write_config(emul, offset, value, size);
+}
+
+static int sandbox_pci_read_config(struct udevice *bus, pci_dev_t devfn,
+				   uint offset, ulong *valuep,
+				   enum pci_size_t size)
+{
+	struct dm_pci_emul_ops *ops;
+	struct udevice *emul;
+	int ret;
+
+	/* Prepare the default response */
+	*valuep = pci_get_ff(size);
+	ret = sandbox_pci_get_emul(bus, devfn, &emul);
+	if (ret)
+		return ret == -ENODEV ? 0 : ret;
+	ops = pci_get_emul_ops(emul);
+	if (!ops || !ops->read_config)
+		return -ENOSYS;
+
+	return ops->read_config(emul, offset, valuep, size);
+}
+
+static int sandbox_pci_child_post_bind(struct udevice *dev)
+{
+	/* Attach an emulator if we can */
+	return dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset, false);
+}
+
+static const struct dm_pci_ops sandbox_pci_ops = {
+	.read_config = sandbox_pci_read_config,
+	.write_config = sandbox_pci_write_config,
+};
+
+static const struct udevice_id sandbox_pci_ids[] = {
+	{ .compatible = "sandbox,pci" },
+	{ }
+};
+
+U_BOOT_DRIVER(pci_sandbox) = {
+	.name	= "pci_sandbox",
+	.id	= UCLASS_PCI,
+	.of_match = sandbox_pci_ids,
+	.ops	= &sandbox_pci_ops,
+	.child_post_bind = sandbox_pci_child_post_bind,
+	.per_child_platdata_auto_alloc_size =
+			sizeof(struct pci_child_platdata),
+};