soc/intel/common: Add PCI driver for USB4 ports

In order to enable SSDT generation for the DMA component of Intel USB4
ports, a PCI driver is required. This patch more or less adds a
`scan_bus` callback that will handle non-PCI devices downstream.

Change-Id: Ib9da051307b883eb99e500114378c9fd842ffc92
Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46141
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/soc/intel/common/block/usb4/Kconfig

@@ -0,0 +1,6 @@
+config SOC_INTEL_COMMON_BLOCK_USB4
+	bool
+	default n
+	help
+	  Minimal PCI Driver for enabling SSDT generation for the DMA component
+	  of Intel Thunderbolt/USB4 ports.

src/soc/intel/common/block/usb4/Makefile.inc

@@ -0,0 +1 @@
+ramstage-$(CONFIG_SOC_INTEL_COMMON_BLOCK_USB4) += usb4.c

src/soc/intel/common/block/usb4/usb4.c

@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <device/device.h>
+#include <device/pci.h>
+#include <device/pci_ids.h>
+
+static const unsigned short pci_device_ids[] = {
+	PCI_DEVICE_ID_INTEL_TGL_TBT_DMA0,
+	PCI_DEVICE_ID_INTEL_TGL_TBT_DMA1,
+	0
+};
+
+static struct device_operations usb4_dev_ops = {
+	.read_resources		= pci_dev_read_resources,
+	.set_resources		= pci_dev_set_resources,
+	.enable_resources	= pci_dev_enable_resources,
+	.scan_bus		= scan_generic_bus,
+	.ops_pci		= &pci_dev_ops_pci,
+};
+
+static const struct pci_driver usb4_driver __pci_driver = {
+	.ops			= &usb4_dev_ops,
+	.vendor			= PCI_VENDOR_ID_INTEL,
+	.devices		= pci_device_ids,
+};