nb/intel/haswell/peg: Add PEG driver stub

This is a port of https://review.coreboot.org/c/coreboot/+/22337 to the
Haswell northbridge.  This code is necessary to support the dGPU of the
t440p. Code was cut and pasted from Sandy Bridge with vendor IDs updated
to the correct Haswell values.  Tested on t440p with dGPU on Ubuntu
18.04.4 with 5.3.0-28 kernel. Without patches dmesg reports Nouveau is
unable to read the VBIOS of the dGPU as it has an invalid checksum (I
checked that the ROM in CBFS is correct). With this patch DRM works
correctly with both the Nouveau driver and the Nvidia proprietary
driver. Windows 10 1909 also tested but generates bluescreen once GPU
driver is loaded.

Change-Id: Ie5f089fb6fd774e6c61f4f9281e2945bd44edf27
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38743
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
diff --git a/src/northbridge/intel/haswell/pcie.c b/src/northbridge/intel/haswell/pcie.c
new file mode 100644
index 0000000..b3a21bf
--- /dev/null
+++ b/src/northbridge/intel/haswell/pcie.c
@@ -0,0 +1,88 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2017-2018 Patrick Rudolph <siro@das-labor.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; version 2 of
+ * the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <console/console.h>
+#include <device/device.h>
+#include <device/pci.h>
+#include <device/pciexp.h>
+#include <device/pci_ids.h>
+#include <assert.h>
+
+static void pcie_disable(struct device *dev)
+{
+	printk(BIOS_INFO, "%s: Disabling device\n", dev_path(dev));
+	dev->enabled = 0;
+}
+
+#if CONFIG(HAVE_ACPI_TABLES)
+static const char *pcie_acpi_name(const struct device *dev)
+{
+	assert(dev);
+
+	if (dev->path.type != DEVICE_PATH_PCI)
+		return NULL;
+
+	assert(dev->bus);
+	if (dev->bus->secondary == 0)
+		switch (dev->path.pci.devfn) {
+		case PCI_DEVFN(1, 0):
+			return "PEGP";
+		case PCI_DEVFN(1, 1):
+			return "PEG1";
+		case PCI_DEVFN(1, 2):
+			return "PEG2";
+		};
+
+	struct device *const port = dev->bus->dev;
+	assert(port);
+	assert(port->bus);
+
+	if (dev->path.pci.devfn == PCI_DEVFN(0, 0) &&
+	    port->bus->secondary == 0 &&
+	    (port->path.pci.devfn == PCI_DEVFN(1, 0) ||
+	    port->path.pci.devfn == PCI_DEVFN(1, 1) ||
+	    port->path.pci.devfn == PCI_DEVFN(1, 2)))
+		return "DEV0";
+
+	return NULL;
+}
+#endif
+
+static struct pci_operations pci_ops = {
+	.set_subsystem = pci_dev_set_subsystem,
+};
+
+static struct device_operations device_ops = {
+	.read_resources		= pci_bus_read_resources,
+	.set_resources		= pci_dev_set_resources,
+	.enable_resources	= pci_bus_enable_resources,
+	.scan_bus		= pciexp_scan_bridge,
+	.reset_bus		= pci_bus_reset,
+	.disable		= pcie_disable,
+	.init			= pci_dev_init,
+	.ops_pci		= &pci_ops,
+#if CONFIG(HAVE_ACPI_TABLES)
+	.acpi_name		= pcie_acpi_name,
+#endif
+};
+
+static const unsigned short pci_device_ids[] = { 0x0c01, 0x0c05, 0x0c09, 0x0c0d, 0 };
+
+static const struct pci_driver pch_pcie __pci_driver = {
+	.ops		= &device_ops,
+	.vendor		= PCI_VENDOR_ID_INTEL,
+	.devices	= pci_device_ids,
+};