Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3363 insertions, 0 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
new file mode 100644
index 000000000..e19b79821
--- /dev/null
+++ b/drivers/pci/probe.c
@@ -0,0 +1,3363 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCI detection and setup code
+ */
+
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/msi.h>
+#include <linux/of_device.h>
+#include <linux/of_pci.h>
+#include <linux/pci_hotplug.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/cpumask.h>
+#include <linux/aer.h>
+#include <linux/acpi.h>
+#include <linux/hypervisor.h>
+#include <linux/irqdomain.h>
+#include <linux/pm_runtime.h>
+#include <linux/bitfield.h>
+#include "pci.h"
+
+#define CARDBUS_LATENCY_TIMER	176	/* secondary latency timer */
+#define CARDBUS_RESERVE_BUSNR	3
+
+static struct resource busn_resource = {
+	.name	= "PCI busn",
+	.start	= 0,
+	.end	= 255,
+	.flags	= IORESOURCE_BUS,
+};
+
+/* Ugh.  Need to stop exporting this to modules. */
+LIST_HEAD(pci_root_buses);
+EXPORT_SYMBOL(pci_root_buses);
+
+static LIST_HEAD(pci_domain_busn_res_list);
+
+struct pci_domain_busn_res {
+	struct list_head list;
+	struct resource res;
+	int domain_nr;
+};
+
+static struct resource *get_pci_domain_busn_res(int domain_nr)
+{
+	struct pci_domain_busn_res *r;
+
+	list_for_each_entry(r, &pci_domain_busn_res_list, list)
+		if (r->domain_nr == domain_nr)
+			return &r->res;
+
+	r = kzalloc(sizeof(*r), GFP_KERNEL);
+	if (!r)
+		return NULL;
+
+	r->domain_nr = domain_nr;
+	r->res.start = 0;
+	r->res.end = 0xff;
+	r->res.flags = IORESOURCE_BUS | IORESOURCE_PCI_FIXED;
+
+	list_add_tail(&r->list, &pci_domain_busn_res_list);
+
+	return &r->res;
+}
+
+/*
+ * Some device drivers need know if PCI is initiated.
+ * Basically, we think PCI is not initiated when there
+ * is no device to be found on the pci_bus_type.
+ */
+int no_pci_devices(void)
+{
+	struct device *dev;
+	int no_devices;
+
+	dev = bus_find_next_device(&pci_bus_type, NULL);
+	no_devices = (dev == NULL);
+	put_device(dev);
+	return no_devices;
+}
+EXPORT_SYMBOL(no_pci_devices);
+
+/*
+ * PCI Bus Class
+ */
+static void release_pcibus_dev(struct device *dev)
+{
+	struct pci_bus *pci_bus = to_pci_bus(dev);
+
+	put_device(pci_bus->bridge);
+	pci_bus_remove_resources(pci_bus);
+	pci_release_bus_of_node(pci_bus);
+	kfree(pci_bus);
+}
+
+static struct class pcibus_class = {
+	.name		= "pci_bus",
+	.dev_release	= &release_pcibus_dev,
+	.dev_groups	= pcibus_groups,
+};
+
+static int __init pcibus_class_init(void)
+{
+	return class_register(&pcibus_class);
+}
+postcore_initcall(pcibus_class_init);
+
+static u64 pci_size(u64 base, u64 maxbase, u64 mask)
+{
+	u64 size = mask & maxbase;	/* Find the significant bits */
+	if (!size)
+		return 0;
+
+	/*
+	 * Get the lowest of them to find the decode size, and from that
+	 * the extent.
+	 */
+	size = size & ~(size-1);
+
+	/*
+	 * base == maxbase can be valid only if the BAR has already been
+	 * programmed with all 1s.
+	 */
+	if (base == maxbase && ((base | (size - 1)) & mask) != mask)
+		return 0;
+
+	return size;
+}
+
+static inline unsigned long decode_bar(struct pci_dev *dev, u32 bar)
+{
+	u32 mem_type;
+	unsigned long flags;
+
+	if ((bar & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
+		flags = bar & ~PCI_BASE_ADDRESS_IO_MASK;
+		flags |= IORESOURCE_IO;
+		return flags;
+	}
+
+	flags = bar & ~PCI_BASE_ADDRESS_MEM_MASK;
+	flags |= IORESOURCE_MEM;
+	if (flags & PCI_BASE_ADDRESS_MEM_PREFETCH)
+		flags |= IORESOURCE_PREFETCH;
+
+	mem_type = bar & PCI_BASE_ADDRESS_MEM_TYPE_MASK;
+	switch (mem_type) {
+	case PCI_BASE_ADDRESS_MEM_TYPE_32:
+		break;
+	case PCI_BASE_ADDRESS_MEM_TYPE_1M:
+		/* 1M mem BAR treated as 32-bit BAR */
+		break;
+	case PCI_BASE_ADDRESS_MEM_TYPE_64:
+		flags |= IORESOURCE_MEM_64;
+		break;
+	default:
+		/* mem unknown type treated as 32-bit BAR */
+		break;
+	}
+	return flags;
+}
+
+#define PCI_COMMAND_DECODE_ENABLE	(PCI_COMMAND_MEMORY | PCI_COMMAND_IO)
+
+/**
+ * __pci_read_base - Read a PCI BAR
+ * @dev: the PCI device
+ * @type: type of the BAR
+ * @res: resource buffer to be filled in
+ * @pos: BAR position in the config space
+ *
+ * Returns 1 if the BAR is 64-bit, or 0 if 32-bit.
+ */
+int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
+		    struct resource *res, unsigned int pos)
+{
+	u32 l = 0, sz = 0, mask;
+	u64 l64, sz64, mask64;
+	u16 orig_cmd;
+	struct pci_bus_region region, inverted_region;
+
+	mask = type ? PCI_ROM_ADDRESS_MASK : ~0;
+
+	/* No printks while decoding is disabled! */
+	if (!dev->mmio_always_on) {
+		pci_read_config_word(dev, PCI_COMMAND, &orig_cmd);
+		if (orig_cmd & PCI_COMMAND_DECODE_ENABLE) {
+			pci_write_config_word(dev, PCI_COMMAND,
+				orig_cmd & ~PCI_COMMAND_DECODE_ENABLE);
+		}
+	}
+
+	res->name = pci_name(dev);
+
+	pci_read_config_dword(dev, pos, &l);
+	pci_write_config_dword(dev, pos, l | mask);
+	pci_read_config_dword(dev, pos, &sz);
+	pci_write_config_dword(dev, pos, l);
+
+	/*
+	 * All bits set in sz means the device isn't working properly.
+	 * If the BAR isn't implemented, all bits must be 0.  If it's a
+	 * memory BAR or a ROM, bit 0 must be clear; if it's an io BAR, bit
+	 * 1 must be clear.
+	 */
+	if (PCI_POSSIBLE_ERROR(sz))
+		sz = 0;
+
+	/*
+	 * I don't know how l can have all bits set.  Copied from old code.
+	 * Maybe it fixes a bug on some ancient platform.
+	 */
+	if (PCI_POSSIBLE_ERROR(l))
+		l = 0;
+
+	if (type == pci_bar_unknown) {
+		res->flags = decode_bar(dev, l);
+		res->flags |= IORESOURCE_SIZEALIGN;
+		if (res->flags & IORESOURCE_IO) {
+			l64 = l & PCI_BASE_ADDRESS_IO_MASK;
+			sz64 = sz & PCI_BASE_ADDRESS_IO_MASK;
+			mask64 = PCI_BASE_ADDRESS_IO_MASK & (u32)IO_SPACE_LIMIT;
+		} else {
+			l64 = l & PCI_BASE_ADDRESS_MEM_MASK;
+			sz64 = sz & PCI_BASE_ADDRESS_MEM_MASK;
+			mask64 = (u32)PCI_BASE_ADDRESS_MEM_MASK;
+		}
+	} else {
+		if (l & PCI_ROM_ADDRESS_ENABLE)
+			res->flags |= IORESOURCE_ROM_ENABLE;
+		l64 = l & PCI_ROM_ADDRESS_MASK;
+		sz64 = sz & PCI_ROM_ADDRESS_MASK;
+		mask64 = PCI_ROM_ADDRESS_MASK;
+	}
+
+	if (res->flags & IORESOURCE_MEM_64) {
+		pci_read_config_dword(dev, pos + 4, &l);
+		pci_write_config_dword(dev, pos + 4, ~0);
+		pci_read_config_dword(dev, pos + 4, &sz);
+		pci_write_config_dword(dev, pos + 4, l);
+
+		l64 |= ((u64)l << 32);
+		sz64 |= ((u64)sz << 32);
+		mask64 |= ((u64)~0 << 32);
+	}
+
+	if (!dev->mmio_always_on && (orig_cmd & PCI_COMMAND_DECODE_ENABLE))
+		pci_write_config_word(dev, PCI_COMMAND, orig_cmd);
+
+	if (!sz64)
+		goto fail;
+
+	sz64 = pci_size(l64, sz64, mask64);
+	if (!sz64) {
+		pci_info(dev, FW_BUG "reg 0x%x: invalid BAR (can't size)\n",
+			 pos);
+		goto fail;
+	}
+
+	if (res->flags & IORESOURCE_MEM_64) {
+		if ((sizeof(pci_bus_addr_t) < 8 || sizeof(resource_size_t) < 8)
+		    && sz64 > 0x100000000ULL) {
+			res->flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED;
+			res->start = 0;
+			res->end = 0;
+			pci_err(dev, "reg 0x%x: can't handle BAR larger than 4GB (size %#010llx)\n",
+				pos, (unsigned long long)sz64);
+			goto out;
+		}
+
+		if ((sizeof(pci_bus_addr_t) < 8) && l) {
+			/* Above 32-bit boundary; try to reallocate */
+			res->flags |= IORESOURCE_UNSET;
+			res->start = 0;
+			res->end = sz64 - 1;
+			pci_info(dev, "reg 0x%x: can't handle BAR above 4GB (bus address %#010llx)\n",
+				 pos, (unsigned long long)l64);
+			goto out;
+		}
+	}
+
+	region.start = l64;
+	region.end = l64 + sz64 - 1;
+
+	pcibios_bus_to_resource(dev->bus, res, &region);
+	pcibios_resource_to_bus(dev->bus, &inverted_region, res);
+
+	/*
+	 * If "A" is a BAR value (a bus address), "bus_to_resource(A)" is
+	 * the corresponding resource address (the physical address used by
+	 * the CPU.  Converting that resource address back to a bus address
+	 * should yield the original BAR value:
+	 *
+	 *     resource_to_bus(bus_to_resource(A)) == A
+	 *
+	 * If it doesn't, CPU accesses to "bus_to_resource(A)" will not
+	 * be claimed by the device.
+	 */
+	if (inverted_region.start != region.start) {
+		res->flags |= IORESOURCE_UNSET;
+		res->start = 0;
+		res->end = region.end - region.start;
+		pci_info(dev, "reg 0x%x: initial BAR value %#010llx invalid\n",
+			 pos, (unsigned long long)region.start);
+	}
+
+	goto out;
+
+
+fail:
+	res->flags = 0;
+out:
+	if (res->flags)
+		pci_info(dev, "reg 0x%x: %pR\n", pos, res);
+
+	return (res->flags & IORESOURCE_MEM_64) ? 1 : 0;
+}
+
+static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
+{
+	unsigned int pos, reg;
+
+	if (dev->non_compliant_bars)
+		return;
+
+	/* Per PCIe r4.0, sec 9.3.4.1.11, the VF BARs are all RO Zero */
+	if (dev->is_virtfn)
+		return;
+
+	for (pos = 0; pos < howmany; pos++) {
+		struct resource *res = &dev->resource[pos];
+		reg = PCI_BASE_ADDRESS_0 + (pos << 2);
+		pos += __pci_read_base(dev, pci_bar_unknown, res, reg);
+	}
+
+	if (rom) {
+		struct resource *res = &dev->resource[PCI_ROM_RESOURCE];
+		dev->rom_base_reg = rom;
+		res->flags = IORESOURCE_MEM | IORESOURCE_PREFETCH |
+				IORESOURCE_READONLY | IORESOURCE_SIZEALIGN;
+		__pci_read_base(dev, pci_bar_mem32, res, rom);
+	}
+}
+
+static void pci_read_bridge_windows(struct pci_dev *bridge)
+{
+	u16 io;
+	u32 pmem, tmp;
+
+	pci_read_config_word(bridge, PCI_IO_BASE, &io);
+	if (!io) {
+		pci_write_config_word(bridge, PCI_IO_BASE, 0xe0f0);
+		pci_read_config_word(bridge, PCI_IO_BASE, &io);
+		pci_write_config_word(bridge, PCI_IO_BASE, 0x0);
+	}
+	if (io)
+		bridge->io_window = 1;
+
+	/*
+	 * DECchip 21050 pass 2 errata: the bridge may miss an address
+	 * disconnect boundary by one PCI data phase.  Workaround: do not
+	 * use prefetching on this device.
+	 */
+	if (bridge->vendor == PCI_VENDOR_ID_DEC && bridge->device == 0x0001)
+		return;
+
+	pci_read_config_dword(bridge, PCI_PREF_MEMORY_BASE, &pmem);
+	if (!pmem) {
+		pci_write_config_dword(bridge, PCI_PREF_MEMORY_BASE,
+					       0xffe0fff0);
+		pci_read_config_dword(bridge, PCI_PREF_MEMORY_BASE, &pmem);
+		pci_write_config_dword(bridge, PCI_PREF_MEMORY_BASE, 0x0);
+	}
+	if (!pmem)
+		return;
+
+	bridge->pref_window = 1;
+
+	if ((pmem & PCI_PREF_RANGE_TYPE_MASK) == PCI_PREF_RANGE_TYPE_64) {
+
+		/*
+		 * Bridge claims to have a 64-bit prefetchable memory
+		 * window; verify that the upper bits are actually
+		 * writable.
+		 */
+		pci_read_config_dword(bridge, PCI_PREF_BASE_UPPER32, &pmem);
+		pci_write_config_dword(bridge, PCI_PREF_BASE_UPPER32,
+				       0xffffffff);
+		pci_read_config_dword(bridge, PCI_PREF_BASE_UPPER32, &tmp);
+		pci_write_config_dword(bridge, PCI_PREF_BASE_UPPER32, pmem);
+		if (tmp)
+			bridge->pref_64_window = 1;
+	}
+}
+
+static void pci_read_bridge_io(struct pci_bus *child)
+{
+	struct pci_dev *dev = child->self;
+	u8 io_base_lo, io_limit_lo;
+	unsigned long io_mask, io_granularity, base, limit;
+	struct pci_bus_region region;
+	struct resource *res;
+
+	io_mask = PCI_IO_RANGE_MASK;
+	io_granularity = 0x1000;
+	if (dev->io_window_1k) {
+		/* Support 1K I/O space granularity */
+		io_mask = PCI_IO_1K_RANGE_MASK;
+		io_granularity = 0x400;
+	}
+
+	res = child->resource[0];
+	pci_read_config_byte(dev, PCI_IO_BASE, &io_base_lo);
+	pci_read_config_byte(dev, PCI_IO_LIMIT, &io_limit_lo);
+	base = (io_base_lo & io_mask) << 8;
+	limit = (io_limit_lo & io_mask) << 8;
+
+	if ((io_base_lo & PCI_IO_RANGE_TYPE_MASK) == PCI_IO_RANGE_TYPE_32) {
+		u16 io_base_hi, io_limit_hi;
+
+		pci_read_config_word(dev, PCI_IO_BASE_UPPER16, &io_base_hi);
+		pci_read_config_word(dev, PCI_IO_LIMIT_UPPER16, &io_limit_hi);
+		base |= ((unsigned long) io_base_hi << 16);
+		limit |= ((unsigned long) io_limit_hi << 16);
+	}
+
+	if (base <= limit) {
+		res->flags = (io_base_lo & PCI_IO_RANGE_TYPE_MASK) | IORESOURCE_IO;
+		region.start = base;
+		region.end = limit + io_granularity - 1;
+		pcibios_bus_to_resource(dev->bus, res, &region);
+		pci_info(dev, "  bridge window %pR\n", res);
+	}
+}
+
+static void pci_read_bridge_mmio(struct pci_bus *child)
+{
+	struct pci_dev *dev = child->self;
+	u16 mem_base_lo, mem_limit_lo;
+	unsigned long base, limit;
+	struct pci_bus_region region;
+	struct resource *res;
+
+	res = child->resource[1];
+	pci_read_config_word(dev, PCI_MEMORY_BASE, &mem_base_lo);
+	pci_read_config_word(dev, PCI_MEMORY_LIMIT, &mem_limit_lo);
+	base = ((unsigned long) mem_base_lo & PCI_MEMORY_RANGE_MASK) << 16;
+	limit = ((unsigned long) mem_limit_lo & PCI_MEMORY_RANGE_MASK) << 16;
+	if (base <= limit) {
+		res->flags = (mem_base_lo & PCI_MEMORY_RANGE_TYPE_MASK) | IORESOURCE_MEM;
+		region.start = base;
+		region.end = limit + 0xfffff;
+		pcibios_bus_to_resource(dev->bus, res, &region);
+		pci_info(dev, "  bridge window %pR\n", res);
+	}
+}
+
+static void pci_read_bridge_mmio_pref(struct pci_bus *child)
+{
+	struct pci_dev *dev = child->self;
+	u16 mem_base_lo, mem_limit_lo;
+	u64 base64, limit64;
+	pci_bus_addr_t base, limit;
+	struct pci_bus_region region;
+	struct resource *res;
+
+	res = child->resource[2];
+	pci_read_config_word(dev, PCI_PREF_MEMORY_BASE, &mem_base_lo);
+	pci_read_config_word(dev, PCI_PREF_MEMORY_LIMIT, &mem_limit_lo);
+	base64 = (mem_base_lo & PCI_PREF_RANGE_MASK) << 16;
+	limit64 = (mem_limit_lo & PCI_PREF_RANGE_MASK) << 16;
+
+	if ((mem_base_lo & PCI_PREF_RANGE_TYPE_MASK) == PCI_PREF_RANGE_TYPE_64) {
+		u32 mem_base_hi, mem_limit_hi;
+
+		pci_read_config_dword(dev, PCI_PREF_BASE_UPPER32, &mem_base_hi);
+		pci_read_config_dword(dev, PCI_PREF_LIMIT_UPPER32, &mem_limit_hi);
+
+		/*
+		 * Some bridges set the base > limit by default, and some
+		 * (broken) BIOSes do not initialize them.  If we find
+		 * this, just assume they are not being used.
+		 */
+		if (mem_base_hi <= mem_limit_hi) {
+			base64 |= (u64) mem_base_hi << 32;
+			limit64 |= (u64) mem_limit_hi << 32;
+		}
+	}
+
+	base = (pci_bus_addr_t) base64;
+	limit = (pci_bus_addr_t) limit64;
+
+	if (base != base64) {
+		pci_err(dev, "can't handle bridge window above 4GB (bus address %#010llx)\n",
+			(unsigned long long) base64);
+		return;
+	}
+
+	if (base <= limit) {
+		res->flags = (mem_base_lo & PCI_PREF_RANGE_TYPE_MASK) |
+					 IORESOURCE_MEM | IORESOURCE_PREFETCH;
+		if (res->flags & PCI_PREF_RANGE_TYPE_64)
+			res->flags |= IORESOURCE_MEM_64;
+		region.start = base;
+		region.end = limit + 0xfffff;
+		pcibios_bus_to_resource(dev->bus, res, &region);
+		pci_info(dev, "  bridge window %pR\n", res);
+	}
+}
+
+void pci_read_bridge_bases(struct pci_bus *child)
+{
+	struct pci_dev *dev = child->self;
+	struct resource *res;
+	int i;
+
+	if (pci_is_root_bus(child))	/* It's a host bus, nothing to read */
+		return;
+
+	pci_info(dev, "PCI bridge to %pR%s\n",
+		 &child->busn_res,
+		 dev->transparent ? " (subtractive decode)" : "");
+
+	pci_bus_remove_resources(child);
+	for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++)
+		child->resource[i] = &dev->resource[PCI_BRIDGE_RESOURCES+i];
+
+	pci_read_bridge_io(child);
+	pci_read_bridge_mmio(child);
+	pci_read_bridge_mmio_pref(child);
+
+	if (dev->transparent) {
+		pci_bus_for_each_resource(child->parent, res, i) {
+			if (res && res->flags) {
+				pci_bus_add_resource(child, res,
+						     PCI_SUBTRACTIVE_DECODE);
+				pci_info(dev, "  bridge window %pR (subtractive decode)\n",
+					   res);
+			}
+		}
+	}
+}
+
+static struct pci_bus *pci_alloc_bus(struct pci_bus *parent)
+{
+	struct pci_bus *b;
+
+	b = kzalloc(sizeof(*b), GFP_KERNEL);
+	if (!b)
+		return NULL;
+
+	INIT_LIST_HEAD(&b->node);
+	INIT_LIST_HEAD(&b->children);
+	INIT_LIST_HEAD(&b->devices);
+	INIT_LIST_HEAD(&b->slots);
+	INIT_LIST_HEAD(&b->resources);
+	b->max_bus_speed = PCI_SPEED_UNKNOWN;
+	b->cur_bus_speed = PCI_SPEED_UNKNOWN;
+#ifdef CONFIG_PCI_DOMAINS_GENERIC
+	if (parent)
+		b->domain_nr = parent->domain_nr;
+#endif
+	return b;
+}
+
+static void pci_release_host_bridge_dev(struct device *dev)
+{
+	struct pci_host_bridge *bridge = to_pci_host_bridge(dev);
+
+	if (bridge->release_fn)
+		bridge->release_fn(bridge);
+
+	pci_free_resource_list(&bridge->windows);
+	pci_free_resource_list(&bridge->dma_ranges);
+	kfree(bridge);
+}
+
+static void pci_init_host_bridge(struct pci_host_bridge *bridge)
+{
+	INIT_LIST_HEAD(&bridge->windows);
+	INIT_LIST_HEAD(&bridge->dma_ranges);
+
+	/*
+	 * We assume we can manage these PCIe features.  Some systems may
+	 * reserve these for use by the platform itself, e.g., an ACPI BIOS
+	 * may implement its own AER handling and use _OSC to prevent the
+	 * OS from interfering.
+	 */
+	bridge->native_aer = 1;
+	bridge->native_pcie_hotplug = 1;
+	bridge->native_shpc_hotplug = 1;
+	bridge->native_pme = 1;
+	bridge->native_ltr = 1;
+	bridge->native_dpc = 1;
+	bridge->domain_nr = PCI_DOMAIN_NR_NOT_SET;
+
+	device_initialize(&bridge->dev);
+}
+
+struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
+{
+	struct pci_host_bridge *bridge;
+
+	bridge = kzalloc(sizeof(*bridge) + priv, GFP_KERNEL);
+	if (!bridge)
+		return NULL;
+
+	pci_init_host_bridge(bridge);
+	bridge->dev.release = pci_release_host_bridge_dev;
+
+	return bridge;
+}
+EXPORT_SYMBOL(pci_alloc_host_bridge);
+
+static void devm_pci_alloc_host_bridge_release(void *data)
+{
+	pci_free_host_bridge(data);
+}
+
+struct pci_host_bridge *devm_pci_alloc_host_bridge(struct device *dev,
+						   size_t priv)
+{
+	int ret;
+	struct pci_host_bridge *bridge;
+
+	bridge = pci_alloc_host_bridge(priv);
+	if (!bridge)
+		return NULL;
+
+	bridge->dev.parent = dev;
+
+	ret = devm_add_action_or_reset(dev, devm_pci_alloc_host_bridge_release,
+				       bridge);
+	if (ret)
+		return NULL;
+
+	ret = devm_of_pci_bridge_init(dev, bridge);
+	if (ret)
+		return NULL;
+
+	return bridge;
+}
+EXPORT_SYMBOL(devm_pci_alloc_host_bridge);
+
+void pci_free_host_bridge(struct pci_host_bridge *bridge)
+{
+	put_device(&bridge->dev);
+}
+EXPORT_SYMBOL(pci_free_host_bridge);
+
+/* Indexed by PCI_X_SSTATUS_FREQ (secondary bus mode and frequency) */
+static const unsigned char pcix_bus_speed[] = {
+	PCI_SPEED_UNKNOWN,		/* 0 */
+	PCI_SPEED_66MHz_PCIX,		/* 1 */
+	PCI_SPEED_100MHz_PCIX,		/* 2 */
+	PCI_SPEED_133MHz_PCIX,		/* 3 */
+	PCI_SPEED_UNKNOWN,		/* 4 */
+	PCI_SPEED_66MHz_PCIX_ECC,	/* 5 */
+	PCI_SPEED_100MHz_PCIX_ECC,	/* 6 */
+	PCI_SPEED_133MHz_PCIX_ECC,	/* 7 */
+	PCI_SPEED_UNKNOWN,		/* 8 */
+	PCI_SPEED_66MHz_PCIX_266,	/* 9 */
+	PCI_SPEED_100MHz_PCIX_266,	/* A */
+	PCI_SPEED_133MHz_PCIX_266,	/* B */
+	PCI_SPEED_UNKNOWN,		/* C */
+	PCI_SPEED_66MHz_PCIX_533,	/* D */
+	PCI_SPEED_100MHz_PCIX_533,	/* E */
+	PCI_SPEED_133MHz_PCIX_533	/* F */
+};
+
+/* Indexed by PCI_EXP_LNKCAP_SLS, PCI_EXP_LNKSTA_CLS */
+const unsigned char pcie_link_speed[] = {
+	PCI_SPEED_UNKNOWN,		/* 0 */
+	PCIE_SPEED_2_5GT,		/* 1 */
+	PCIE_SPEED_5_0GT,		/* 2 */
+	PCIE_SPEED_8_0GT,		/* 3 */
+	PCIE_SPEED_16_0GT,		/* 4 */
+	PCIE_SPEED_32_0GT,		/* 5 */
+	PCIE_SPEED_64_0GT,		/* 6 */
+	PCI_SPEED_UNKNOWN,		/* 7 */
+	PCI_SPEED_UNKNOWN,		/* 8 */
+	PCI_SPEED_UNKNOWN,		/* 9 */
+	PCI_SPEED_UNKNOWN,		/* A */
+	PCI_SPEED_UNKNOWN,		/* B */
+	PCI_SPEED_UNKNOWN,		/* C */
+	PCI_SPEED_UNKNOWN,		/* D */
+	PCI_SPEED_UNKNOWN,		/* E */
+	PCI_SPEED_UNKNOWN		/* F */
+};
+EXPORT_SYMBOL_GPL(pcie_link_speed);
+
+const char *pci_speed_string(enum pci_bus_speed speed)
+{
+	/* Indexed by the pci_bus_speed enum */
+	static const char *speed_strings[] = {
+	    "33 MHz PCI",		/* 0x00 */
+	    "66 MHz PCI",		/* 0x01 */
+	    "66 MHz PCI-X",		/* 0x02 */
+	    "100 MHz PCI-X",		/* 0x03 */
+	    "133 MHz PCI-X",		/* 0x04 */
+	    NULL,			/* 0x05 */
+	    NULL,			/* 0x06 */
+	    NULL,			/* 0x07 */
+	    NULL,			/* 0x08 */
+	    "66 MHz PCI-X 266",		/* 0x09 */
+	    "100 MHz PCI-X 266",	/* 0x0a */
+	    "133 MHz PCI-X 266",	/* 0x0b */
+	    "Unknown AGP",		/* 0x0c */
+	    "1x AGP",			/* 0x0d */
+	    "2x AGP",			/* 0x0e */
+	    "4x AGP",			/* 0x0f */
+	    "8x AGP",			/* 0x10 */
+	    "66 MHz PCI-X 533",		/* 0x11 */
+	    "100 MHz PCI-X 533",	/* 0x12 */
+	    "133 MHz PCI-X 533",	/* 0x13 */
+	    "2.5 GT/s PCIe",		/* 0x14 */
+	    "5.0 GT/s PCIe",		/* 0x15 */
+	    "8.0 GT/s PCIe",		/* 0x16 */
+	    "16.0 GT/s PCIe",		/* 0x17 */
+	    "32.0 GT/s PCIe",		/* 0x18 */
+	    "64.0 GT/s PCIe",		/* 0x19 */
+	};
+
+	if (speed < ARRAY_SIZE(speed_strings))
+		return speed_strings[speed];
+	return "Unknown";
+}
+EXPORT_SYMBOL_GPL(pci_speed_string);
+
+void pcie_update_link_speed(struct pci_bus *bus, u16 linksta)
+{
+	bus->cur_bus_speed = pcie_link_speed[linksta & PCI_EXP_LNKSTA_CLS];
+}
+EXPORT_SYMBOL_GPL(pcie_update_link_speed);
+
+static unsigned char agp_speeds[] = {
+	AGP_UNKNOWN,
+	AGP_1X,
+	AGP_2X,
+	AGP_4X,
+	AGP_8X
+};
+
+static enum pci_bus_speed agp_speed(int agp3, int agpstat)
+{
+	int index = 0;
+
+	if (agpstat & 4)
+		index = 3;
+	else if (agpstat & 2)
+		index = 2;
+	else if (agpstat & 1)
+		index = 1;
+	else
+		goto out;
+
+	if (agp3) {
+		index += 2;
+		if (index == 5)
+			index = 0;
+	}
+
+ out:
+	return agp_speeds[index];
+}
+
+static void pci_set_bus_speed(struct pci_bus *bus)
+{
+	struct pci_dev *bridge = bus->self;
+	int pos;
+
+	pos = pci_find_capability(bridge, PCI_CAP_ID_AGP);
+	if (!pos)
+		pos = pci_find_capability(bridge, PCI_CAP_ID_AGP3);
+	if (pos) {
+		u32 agpstat, agpcmd;
+
+		pci_read_config_dword(bridge, pos + PCI_AGP_STATUS, &agpstat);
+		bus->max_bus_speed = agp_speed(agpstat & 8, agpstat & 7);
+
+		pci_read_config_dword(bridge, pos + PCI_AGP_COMMAND, &agpcmd);
+		bus->cur_bus_speed = agp_speed(agpstat & 8, agpcmd & 7);
+	}
+
+	pos = pci_find_capability(bridge, PCI_CAP_ID_PCIX);
+	if (pos) {
+		u16 status;
+		enum pci_bus_speed max;
+
+		pci_read_config_word(bridge, pos + PCI_X_BRIDGE_SSTATUS,
+				     &status);
+
+		if (status & PCI_X_SSTATUS_533MHZ) {
+			max = PCI_SPEED_133MHz_PCIX_533;
+		} else if (status & PCI_X_SSTATUS_266MHZ) {
+			max = PCI_SPEED_133MHz_PCIX_266;
+		} else if (status & PCI_X_SSTATUS_133MHZ) {
+			if ((status & PCI_X_SSTATUS_VERS) == PCI_X_SSTATUS_V2)
+				max = PCI_SPEED_133MHz_PCIX_ECC;
+			else
+				max = PCI_SPEED_133MHz_PCIX;
+		} else {
+			max = PCI_SPEED_66MHz_PCIX;
+		}
+
+		bus->max_bus_speed = max;
+		bus->cur_bus_speed = pcix_bus_speed[
+			(status & PCI_X_SSTATUS_FREQ) >> 6];
+
+		return;
+	}
+
+	if (pci_is_pcie(bridge)) {
+		u32 linkcap;
+		u16 linksta;
+
+		pcie_capability_read_dword(bridge, PCI_EXP_LNKCAP, &linkcap);
+		bus->max_bus_speed = pcie_link_speed[linkcap & PCI_EXP_LNKCAP_SLS];
+		bridge->link_active_reporting = !!(linkcap & PCI_EXP_LNKCAP_DLLLARC);
+
+		pcie_capability_read_word(bridge, PCI_EXP_LNKSTA, &linksta);
+		pcie_update_link_speed(bus, linksta);
+	}
+}
+
+static struct irq_domain *pci_host_bridge_msi_domain(struct pci_bus *bus)
+{
+	struct irq_domain *d;
+
+	/* If the host bridge driver sets a MSI domain of the bridge, use it */
+	d = dev_get_msi_domain(bus->bridge);
+
+	/*
+	 * Any firmware interface that can resolve the msi_domain
+	 * should be called from here.
+	 */
+	if (!d)
+		d = pci_host_bridge_of_msi_domain(bus);
+	if (!d)
+		d = pci_host_bridge_acpi_msi_domain(bus);
+
+#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
+	/*
+	 * If no IRQ domain was found via the OF tree, try looking it up
+	 * directly through the fwnode_handle.
+	 */
+	if (!d) {
+		struct fwnode_handle *fwnode = pci_root_bus_fwnode(bus);
+
+		if (fwnode)
+			d = irq_find_matching_fwnode(fwnode,
+						     DOMAIN_BUS_PCI_MSI);
+	}
+#endif
+
+	return d;
+}
+
+static void pci_set_bus_msi_domain(struct pci_bus *bus)
+{
+	struct irq_domain *d;
+	struct pci_bus *b;
+
+	/*
+	 * The bus can be a root bus, a subordinate bus, or a virtual bus
+	 * created by an SR-IOV device.  Walk up to the first bridge device
+	 * found or derive the domain from the host bridge.
+	 */
+	for (b = bus, d = NULL; !d && !pci_is_root_bus(b); b = b->parent) {
+		if (b->self)
+			d = dev_get_msi_domain(&b->self->dev);
+	}
+
+	if (!d)
+		d = pci_host_bridge_msi_domain(b);
+
+	dev_set_msi_domain(&bus->dev, d);
+}
+
+static int pci_register_host_bridge(struct pci_host_bridge *bridge)
+{
+	struct device *parent = bridge->dev.parent;
+	struct resource_entry *window, *next, *n;
+	struct pci_bus *bus, *b;
+	resource_size_t offset, next_offset;
+	LIST_HEAD(resources);
+	struct resource *res, *next_res;
+	char addr[64], *fmt;
+	const char *name;
+	int err;
+
+	bus = pci_alloc_bus(NULL);
+	if (!bus)
+		return -ENOMEM;
+
+	bridge->bus = bus;
+
+	bus->sysdata = bridge->sysdata;
+	bus->ops = bridge->ops;
+	bus->number = bus->busn_res.start = bridge->busnr;
+#ifdef CONFIG_PCI_DOMAINS_GENERIC
+	if (bridge->domain_nr == PCI_DOMAIN_NR_NOT_SET)
+		bus->domain_nr = pci_bus_find_domain_nr(bus, parent);
+	else
+		bus->domain_nr = bridge->domain_nr;
+#endif
+
+	b = pci_find_bus(pci_domain_nr(bus), bridge->busnr);
+	if (b) {
+		/* Ignore it if we already got here via a different bridge */
+		dev_dbg(&b->dev, "bus already known\n");
+		err = -EEXIST;
+		goto free;
+	}
+
+	dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(bus),
+		     bridge->busnr);
+
+	err = pcibios_root_bridge_prepare(bridge);
+	if (err)
+		goto free;
+
+	/* Temporarily move resources off the list */
+	list_splice_init(&bridge->windows, &resources);
+	err = device_add(&bridge->dev);
+	if (err) {
+		put_device(&bridge->dev);
+		goto free;
+	}
+	bus->bridge = get_device(&bridge->dev);
+	device_enable_async_suspend(bus->bridge);
+	pci_set_bus_of_node(bus);
+	pci_set_bus_msi_domain(bus);
+	if (bridge->msi_domain && !dev_get_msi_domain(&bus->dev) &&
+	    !pci_host_of_has_msi_map(parent))
+		bus->bus_flags |= PCI_BUS_FLAGS_NO_MSI;
+
+	if (!parent)
+		set_dev_node(bus->bridge, pcibus_to_node(bus));
+
+	bus->dev.class = &pcibus_class;
+	bus->dev.parent = bus->bridge;
+
+	dev_set_name(&bus->dev, "%04x:%02x", pci_domain_nr(bus), bus->number);
+	name = dev_name(&bus->dev);
+
+	err = device_register(&bus->dev);
+	if (err)
+		goto unregister;
+
+	pcibios_add_bus(bus);
+
+	if (bus->ops->add_bus) {
+		err = bus->ops->add_bus(bus);
+		if (WARN_ON(err < 0))
+			dev_err(&bus->dev, "failed to add bus: %d\n", err);
+	}
+
+	/* Create legacy_io and legacy_mem files for this bus */
+	pci_create_legacy_files(bus);
+
+	if (parent)
+		dev_info(parent, "PCI host bridge to bus %s\n", name);
+	else
+		pr_info("PCI host bridge to bus %s\n", name);
+
+	if (nr_node_ids > 1 && pcibus_to_node(bus) == NUMA_NO_NODE)
+		dev_warn(&bus->dev, "Unknown NUMA node; performance will be reduced\n");
+
+	/* Coalesce contiguous windows */
+	resource_list_for_each_entry_safe(window, n, &resources) {
+		if (list_is_last(&window->node, &resources))
+			break;
+
+		next = list_next_entry(window, node);
+		offset = window->offset;
+		res = window->res;
+		next_offset = next->offset;
+		next_res = next->res;
+
+		if (res->flags != next_res->flags || offset != next_offset)
+			continue;
+
+		if (res->end + 1 == next_res->start) {
+			next_res->start = res->start;
+			res->flags = res->start = res->end = 0;
+		}
+	}
+
+	/* Add initial resources to the bus */
+	resource_list_for_each_entry_safe(window, n, &resources) {
+		offset = window->offset;
+		res = window->res;
+		if (!res->flags && !res->start && !res->end) {
+			release_resource(res);
+			resource_list_destroy_entry(window);
+			continue;
+		}
+
+		list_move_tail(&window->node, &bridge->windows);
+
+		if (res->flags & IORESOURCE_BUS)
+			pci_bus_insert_busn_res(bus, bus->number, res->end);
+		else
+			pci_bus_add_resource(bus, res, 0);
+
+		if (offset) {
+			if (resource_type(res) == IORESOURCE_IO)
+				fmt = " (bus address [%#06llx-%#06llx])";
+			else
+				fmt = " (bus address [%#010llx-%#010llx])";
+
+			snprintf(addr, sizeof(addr), fmt,
+				 (unsigned long long)(res->start - offset),
+				 (unsigned long long)(res->end - offset));
+		} else
+			addr[0] = '\0';
+
+		dev_info(&bus->dev, "root bus resource %pR%s\n", res, addr);
+	}
+
+	down_write(&pci_bus_sem);
+	list_add_tail(&bus->node, &pci_root_buses);
+	up_write(&pci_bus_sem);
+
+	return 0;
+
+unregister:
+	put_device(&bridge->dev);
+	device_del(&bridge->dev);
+
+free:
+	kfree(bus);
+	return err;
+}
+
+static bool pci_bridge_child_ext_cfg_accessible(struct pci_dev *bridge)
+{
+	int pos;
+	u32 status;
+
+	/*
+	 * If extended config space isn't accessible on a bridge's primary
+	 * bus, we certainly can't access it on the secondary bus.
+	 */
+	if (bridge->bus->bus_flags & PCI_BUS_FLAGS_NO_EXTCFG)
+		return false;
+
+	/*
+	 * PCIe Root Ports and switch ports are PCIe on both sides, so if
+	 * extended config space is accessible on the primary, it's also
+	 * accessible on the secondary.
+	 */
+	if (pci_is_pcie(bridge) &&
+	    (pci_pcie_type(bridge) == PCI_EXP_TYPE_ROOT_PORT ||
+	     pci_pcie_type(bridge) == PCI_EXP_TYPE_UPSTREAM ||
+	     pci_pcie_type(bridge) == PCI_EXP_TYPE_DOWNSTREAM))
+		return true;
+
+	/*
+	 * For the other bridge types:
+	 *   - PCI-to-PCI bridges
+	 *   - PCIe-to-PCI/PCI-X forward bridges
+	 *   - PCI/PCI-X-to-PCIe reverse bridges
+	 * extended config space on the secondary side is only accessible
+	 * if the bridge supports PCI-X Mode 2.
+	 */
+	pos = pci_find_capability(bridge, PCI_CAP_ID_PCIX);
+	if (!pos)
+		return false;
+
+	pci_read_config_dword(bridge, pos + PCI_X_STATUS, &status);
+	return status & (PCI_X_STATUS_266MHZ | PCI_X_STATUS_533MHZ);
+}
+
+static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
+					   struct pci_dev *bridge, int busnr)
+{
+	struct pci_bus *child;
+	struct pci_host_bridge *host;
+	int i;
+	int ret;
+
+	/* Allocate a new bus and inherit stuff from the parent */
+	child = pci_alloc_bus(parent);
+	if (!child)
+		return NULL;
+
+	child->parent = parent;
+	child->sysdata = parent->sysdata;
+	child->bus_flags = parent->bus_flags;
+
+	host = pci_find_host_bridge(parent);
+	if (host->child_ops)
+		child->ops = host->child_ops;
+	else
+		child->ops = parent->ops;
+
+	/*
+	 * Initialize some portions of the bus device, but don't register
+	 * it now as the parent is not properly set up yet.
+	 */
+	child->dev.class = &pcibus_class;
+	dev_set_name(&child->dev, "%04x:%02x", pci_domain_nr(child), busnr);
+
+	/* Set up the primary, secondary and subordinate bus numbers */
+	child->number = child->busn_res.start = busnr;
+	child->primary = parent->busn_res.start;
+	child->busn_res.end = 0xff;
+
+	if (!bridge) {
+		child->dev.parent = parent->bridge;
+		goto add_dev;
+	}
+
+	child->self = bridge;
+	child->bridge = get_device(&bridge->dev);
+	child->dev.parent = child->bridge;
+	pci_set_bus_of_node(child);
+	pci_set_bus_speed(child);
+
+	/*
+	 * Check whether extended config space is accessible on the child
+	 * bus.  Note that we currently assume it is always accessible on
+	 * the root bus.
+	 */
+	if (!pci_bridge_child_ext_cfg_accessible(bridge)) {
+		child->bus_flags |= PCI_BUS_FLAGS_NO_EXTCFG;
+		pci_info(child, "extended config space not accessible\n");
+	}
+
+	/* Set up default resource pointers and names */
+	for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) {
+		child->resource[i] = &bridge->resource[PCI_BRIDGE_RESOURCES+i];
+		child->resource[i]->name = child->name;
+	}
+	bridge->subordinate = child;
+
+add_dev:
+	pci_set_bus_msi_domain(child);
+	ret = device_register(&child->dev);
+	WARN_ON(ret < 0);
+
+	pcibios_add_bus(child);
+
+	if (child->ops->add_bus) {
+		ret = child->ops->add_bus(child);
+		if (WARN_ON(ret < 0))
+			dev_err(&child->dev, "failed to add bus: %d\n", ret);
+	}
+
+	/* Create legacy_io and legacy_mem files for this bus */
+	pci_create_legacy_files(child);
+
+	return child;
+}
+
+struct pci_bus *pci_add_new_bus(struct pci_bus *parent, struct pci_dev *dev,
+				int busnr)
+{
+	struct pci_bus *child;
+
+	child = pci_alloc_child_bus(parent, dev, busnr);
+	if (child) {
+		down_write(&pci_bus_sem);
+		list_add_tail(&child->node, &parent->children);
+		up_write(&pci_bus_sem);
+	}
+	return child;
+}
+EXPORT_SYMBOL(pci_add_new_bus);
+
+static void pci_enable_crs(struct pci_dev *pdev)
+{
+	u16 root_cap = 0;
+
+	/* Enable CRS Software Visibility if supported */
+	pcie_capability_read_word(pdev, PCI_EXP_RTCAP, &root_cap);
+	if (root_cap & PCI_EXP_RTCAP_CRSVIS)
+		pcie_capability_set_word(pdev, PCI_EXP_RTCTL,
+					 PCI_EXP_RTCTL_CRSSVE);
+}
+
+static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
+					      unsigned int available_buses);
+/**
+ * pci_ea_fixed_busnrs() - Read fixed Secondary and Subordinate bus
+ * numbers from EA capability.
+ * @dev: Bridge
+ * @sec: updated with secondary bus number from EA
+ * @sub: updated with subordinate bus number from EA
+ *
+ * If @dev is a bridge with EA capability that specifies valid secondary
+ * and subordinate bus numbers, return true with the bus numbers in @sec
+ * and @sub.  Otherwise return false.
+ */
+static bool pci_ea_fixed_busnrs(struct pci_dev *dev, u8 *sec, u8 *sub)
+{
+	int ea, offset;
+	u32 dw;
+	u8 ea_sec, ea_sub;
+
+	if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE)
+		return false;
+
+	/* find PCI EA capability in list */
+	ea = pci_find_capability(dev, PCI_CAP_ID_EA);
+	if (!ea)
+		return false;
+
+	offset = ea + PCI_EA_FIRST_ENT;
+	pci_read_config_dword(dev, offset, &dw);
+	ea_sec =  dw & PCI_EA_SEC_BUS_MASK;
+	ea_sub = (dw & PCI_EA_SUB_BUS_MASK) >> PCI_EA_SUB_BUS_SHIFT;
+	if (ea_sec  == 0 || ea_sub < ea_sec)
+		return false;
+
+	*sec = ea_sec;
+	*sub = ea_sub;
+	return true;
+}
+
+/*
+ * pci_scan_bridge_extend() - Scan buses behind a bridge
+ * @bus: Parent bus the bridge is on
+ * @dev: Bridge itself
+ * @max: Starting subordinate number of buses behind this bridge
+ * @available_buses: Total number of buses available for this bridge and
+ *		     the devices below. After the minimal bus space has
+ *		     been allocated the remaining buses will be
+ *		     distributed equally between hotplug-capable bridges.
+ * @pass: Either %0 (scan already configured bridges) or %1 (scan bridges
+ *        that need to be reconfigured.
+ *
+ * If it's a bridge, configure it and scan the bus behind it.
+ * For CardBus bridges, we don't scan behind as the devices will
+ * be handled by the bridge driver itself.
+ *
+ * We need to process bridges in two passes -- first we scan those
+ * already configured by the BIOS and after we are done with all of
+ * them, we proceed to assigning numbers to the remaining buses in
+ * order to avoid overlaps between old and new bus numbers.
+ *
+ * Return: New subordinate number covering all buses behind this bridge.
+ */
+static int pci_scan_bridge_extend(struct pci_bus *bus, struct pci_dev *dev,
+				  int max, unsigned int available_buses,
+				  int pass)
+{
+	struct pci_bus *child;
+	int is_cardbus = (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS);
+	u32 buses, i, j = 0;
+	u16 bctl;
+	u8 primary, secondary, subordinate;
+	int broken = 0;
+	bool fixed_buses;
+	u8 fixed_sec, fixed_sub;
+	int next_busnr;
+
+	/*
+	 * Make sure the bridge is powered on to be able to access config
+	 * space of devices below it.
+	 */
+	pm_runtime_get_sync(&dev->dev);
+
+	pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses);
+	primary = buses & 0xFF;
+	secondary = (buses >> 8) & 0xFF;
+	subordinate = (buses >> 16) & 0xFF;
+
+	pci_dbg(dev, "scanning [bus %02x-%02x] behind bridge, pass %d\n",
+		secondary, subordinate, pass);
+
+	if (!primary && (primary != bus->number) && secondary && subordinate) {
+		pci_warn(dev, "Primary bus is hard wired to 0\n");
+		primary = bus->number;
+	}
+
+	/* Check if setup is sensible at all */
+	if (!pass &&
+	    (primary != bus->number || secondary <= bus->number ||
+	     secondary > subordinate)) {
+		pci_info(dev, "bridge configuration invalid ([bus %02x-%02x]), reconfiguring\n",
+			 secondary, subordinate);
+		broken = 1;
+	}
+
+	/*
+	 * Disable Master-Abort Mode during probing to avoid reporting of
+	 * bus errors in some architectures.
+	 */
+	pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &bctl);
+	pci_write_config_word(dev, PCI_BRIDGE_CONTROL,
+			      bctl & ~PCI_BRIDGE_CTL_MASTER_ABORT);
+
+	pci_enable_crs(dev);
+
+	if ((secondary || subordinate) && !pcibios_assign_all_busses() &&
+	    !is_cardbus && !broken) {
+		unsigned int cmax, buses;
+
+		/*
+		 * Bus already configured by firmware, process it in the
+		 * first pass and just note the configuration.
+		 */
+		if (pass)
+			goto out;
+
+		/*
+		 * The bus might already exist for two reasons: Either we
+		 * are rescanning the bus or the bus is reachable through
+		 * more than one bridge. The second case can happen with
+		 * the i450NX chipset.
+		 */
+		child = pci_find_bus(pci_domain_nr(bus), secondary);
+		if (!child) {
+			child = pci_add_new_bus(bus, dev, secondary);
+			if (!child)
+				goto out;
+			child->primary = primary;
+			pci_bus_insert_busn_res(child, secondary, subordinate);
+			child->bridge_ctl = bctl;
+		}
+
+		buses = subordinate - secondary;
+		cmax = pci_scan_child_bus_extend(child, buses);
+		if (cmax > subordinate)
+			pci_warn(dev, "bridge has subordinate %02x but max busn %02x\n",
+				 subordinate, cmax);
+
+		/* Subordinate should equal child->busn_res.end */
+		if (subordinate > max)
+			max = subordinate;
+	} else {
+
+		/*
+		 * We need to assign a number to this bus which we always
+		 * do in the second pass.
+		 */
+		if (!pass) {
+			if (pcibios_assign_all_busses() || broken || is_cardbus)
+
+				/*
+				 * Temporarily disable forwarding of the
+				 * configuration cycles on all bridges in
+				 * this bus segment to avoid possible
+				 * conflicts in the second pass between two
+				 * bridges programmed with overlapping bus
+				 * ranges.
+				 */
+				pci_write_config_dword(dev, PCI_PRIMARY_BUS,
+						       buses & ~0xffffff);
+			goto out;
+		}
+
+		/* Clear errors */
+		pci_write_config_word(dev, PCI_STATUS, 0xffff);
+
+		/* Read bus numbers from EA Capability (if present) */
+		fixed_buses = pci_ea_fixed_busnrs(dev, &fixed_sec, &fixed_sub);
+		if (fixed_buses)
+			next_busnr = fixed_sec;
+		else
+			next_busnr = max + 1;
+
+		/*
+		 * Prevent assigning a bus number that already exists.
+		 * This can happen when a bridge is hot-plugged, so in this
+		 * case we only re-scan this bus.
+		 */
+		child = pci_find_bus(pci_domain_nr(bus), next_busnr);
+		if (!child) {
+			child = pci_add_new_bus(bus, dev, next_busnr);
+			if (!child)
+				goto out;
+			pci_bus_insert_busn_res(child, next_busnr,
+						bus->busn_res.end);
+		}
+		max++;
+		if (available_buses)
+			available_buses--;
+
+		buses = (buses & 0xff000000)
+		      | ((unsigned int)(child->primary)     <<  0)
+		      | ((unsigned int)(child->busn_res.start)   <<  8)
+		      | ((unsigned int)(child->busn_res.end) << 16);
+
+		/*
+		 * yenta.c forces a secondary latency timer of 176.
+		 * Copy that behaviour here.
+		 */
+		if (is_cardbus) {
+			buses &= ~0xff000000;
+			buses |= CARDBUS_LATENCY_TIMER << 24;
+		}
+
+		/* We need to blast all three values with a single write */
+		pci_write_config_dword(dev, PCI_PRIMARY_BUS, buses);
+
+		if (!is_cardbus) {
+			child->bridge_ctl = bctl;
+			max = pci_scan_child_bus_extend(child, available_buses);
+		} else {
+
+			/*
+			 * For CardBus bridges, we leave 4 bus numbers as
+			 * cards with a PCI-to-PCI bridge can be inserted
+			 * later.
+			 */
+			for (i = 0; i < CARDBUS_RESERVE_BUSNR; i++) {
+				struct pci_bus *parent = bus;
+				if (pci_find_bus(pci_domain_nr(bus),
+							max+i+1))
+					break;
+				while (parent->parent) {
+					if ((!pcibios_assign_all_busses()) &&
+					    (parent->busn_res.end > max) &&
+					    (parent->busn_res.end <= max+i)) {
+						j = 1;
+					}
+					parent = parent->parent;
+				}
+				if (j) {
+
+					/*
+					 * Often, there are two CardBus
+					 * bridges -- try to leave one
+					 * valid bus number for each one.
+					 */
+					i /= 2;
+					break;
+				}
+			}
+			max += i;
+		}
+
+		/*
+		 * Set subordinate bus number to its real value.
+		 * If fixed subordinate bus number exists from EA
+		 * capability then use it.
+		 */
+		if (fixed_buses)
+			max = fixed_sub;
+		pci_bus_update_busn_res_end(child, max);
+		pci_write_config_byte(dev, PCI_SUBORDINATE_BUS, max);
+	}
+
+	sprintf(child->name,
+		(is_cardbus ? "PCI CardBus %04x:%02x" : "PCI Bus %04x:%02x"),
+		pci_domain_nr(bus), child->number);
+
+	/* Check that all devices are accessible */
+	while (bus->parent) {
+		if ((child->busn_res.end > bus->busn_res.end) ||
+		    (child->number > bus->busn_res.end) ||
+		    (child->number < bus->number) ||
+		    (child->busn_res.end < bus->number)) {
+			dev_info(&dev->dev, "devices behind bridge are unusable because %pR cannot be assigned for them\n",
+				 &child->busn_res);
+			break;
+		}
+		bus = bus->parent;
+	}
+
+out:
+	pci_write_config_word(dev, PCI_BRIDGE_CONTROL, bctl);
+
+	pm_runtime_put(&dev->dev);
+
+	return max;
+}
+
+/*
+ * pci_scan_bridge() - Scan buses behind a bridge
+ * @bus: Parent bus the bridge is on
+ * @dev: Bridge itself
+ * @max: Starting subordinate number of buses behind this bridge
+ * @pass: Either %0 (scan already configured bridges) or %1 (scan bridges
+ *        that need to be reconfigured.
+ *
+ * If it's a bridge, configure it and scan the bus behind it.
+ * For CardBus bridges, we don't scan behind as the devices will
+ * be handled by the bridge driver itself.
+ *
+ * We need to process bridges in two passes -- first we scan those
+ * already configured by the BIOS and after we are done with all of
+ * them, we proceed to assigning numbers to the remaining buses in
+ * order to avoid overlaps between old and new bus numbers.
+ *
+ * Return: New subordinate number covering all buses behind this bridge.
+ */
+int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
+{
+	return pci_scan_bridge_extend(bus, dev, max, 0, pass);
+}
+EXPORT_SYMBOL(pci_scan_bridge);
+
+/*
+ * Read interrupt line and base address registers.
+ * The architecture-dependent code can tweak these, of course.
+ */
+static void pci_read_irq(struct pci_dev *dev)
+{
+	unsigned char irq;
+
+	/* VFs are not allowed to use INTx, so skip the config reads */
+	if (dev->is_virtfn) {
+		dev->pin = 0;
+		dev->irq = 0;
+		return;
+	}
+
+	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &irq);
+	dev->pin = irq;
+	if (irq)
+		pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &irq);
+	dev->irq = irq;
+}
+
+void set_pcie_port_type(struct pci_dev *pdev)
+{
+	int pos;
+	u16 reg16;
+	int type;
+	struct pci_dev *parent;
+
+	pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
+	if (!pos)
+		return;
+
+	pdev->pcie_cap = pos;
+	pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, &reg16);
+	pdev->pcie_flags_reg = reg16;
+	pci_read_config_dword(pdev, pos + PCI_EXP_DEVCAP, &pdev->devcap);
+	pdev->pcie_mpss = FIELD_GET(PCI_EXP_DEVCAP_PAYLOAD, pdev->devcap);
+
+	parent = pci_upstream_bridge(pdev);
+	if (!parent)
+		return;
+
+	/*
+	 * Some systems do not identify their upstream/downstream ports
+	 * correctly so detect impossible configurations here and correct
+	 * the port type accordingly.
+	 */
+	type = pci_pcie_type(pdev);
+	if (type == PCI_EXP_TYPE_DOWNSTREAM) {
+		/*
+		 * If pdev claims to be downstream port but the parent
+		 * device is also downstream port assume pdev is actually
+		 * upstream port.
+		 */
+		if (pcie_downstream_port(parent)) {
+			pci_info(pdev, "claims to be downstream port but is acting as upstream port, correcting type\n");
+			pdev->pcie_flags_reg &= ~PCI_EXP_FLAGS_TYPE;
+			pdev->pcie_flags_reg |= PCI_EXP_TYPE_UPSTREAM;
+		}
+	} else if (type == PCI_EXP_TYPE_UPSTREAM) {
+		/*
+		 * If pdev claims to be upstream port but the parent
+		 * device is also upstream port assume pdev is actually
+		 * downstream port.
+		 */
+		if (pci_pcie_type(parent) == PCI_EXP_TYPE_UPSTREAM) {
+			pci_info(pdev, "claims to be upstream port but is acting as downstream port, correcting type\n");
+			pdev->pcie_flags_reg &= ~PCI_EXP_FLAGS_TYPE;
+			pdev->pcie_flags_reg |= PCI_EXP_TYPE_DOWNSTREAM;
+		}
+	}
+}
+
+void set_pcie_hotplug_bridge(struct pci_dev *pdev)
+{
+	u32 reg32;
+
+	pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &reg32);
+	if (reg32 & PCI_EXP_SLTCAP_HPC)
+		pdev->is_hotplug_bridge = 1;
+}
+
+static void set_pcie_thunderbolt(struct pci_dev *dev)
+{
+	u16 vsec;
+
+	/* Is the device part of a Thunderbolt controller? */
+	vsec = pci_find_vsec_capability(dev, PCI_VENDOR_ID_INTEL, PCI_VSEC_ID_INTEL_TBT);
+	if (vsec)
+		dev->is_thunderbolt = 1;
+}
+
+static void set_pcie_untrusted(struct pci_dev *dev)
+{
+	struct pci_dev *parent;
+
+	/*
+	 * If the upstream bridge is untrusted we treat this device
+	 * untrusted as well.
+	 */
+	parent = pci_upstream_bridge(dev);
+	if (parent && (parent->untrusted || parent->external_facing))
+		dev->untrusted = true;
+}
+
+static void pci_set_removable(struct pci_dev *dev)
+{
+	struct pci_dev *parent = pci_upstream_bridge(dev);
+
+	/*
+	 * We (only) consider everything downstream from an external_facing
+	 * device to be removable by the user. We're mainly concerned with
+	 * consumer platforms with user accessible thunderbolt ports that are
+	 * vulnerable to DMA attacks, and we expect those ports to be marked by
+	 * the firmware as external_facing. Devices in traditional hotplug
+	 * slots can technically be removed, but the expectation is that unless
+	 * the port is marked with external_facing, such devices are less
+	 * accessible to user / may not be removed by end user, and thus not
+	 * exposed as "removable" to userspace.
+	 */
+	if (parent &&
+	    (parent->external_facing || dev_is_removable(&parent->dev)))
+		dev_set_removable(&dev->dev, DEVICE_REMOVABLE);
+}
+
+/**
+ * pci_ext_cfg_is_aliased - Is ext config space just an alias of std config?
+ * @dev: PCI device
+ *
+ * PCI Express to PCI/PCI-X Bridge Specification, rev 1.0, 4.1.4 says that
+ * when forwarding a type1 configuration request the bridge must check that
+ * the extended register address field is zero.  The bridge is not permitted
+ * to forward the transactions and must handle it as an Unsupported Request.
+ * Some bridges do not follow this rule and simply drop the extended register
+ * bits, resulting in the standard config space being aliased, every 256
+ * bytes across the entire configuration space.  Test for this condition by
+ * comparing the first dword of each potential alias to the vendor/device ID.
+ * Known offenders:
+ *   ASM1083/1085 PCIe-to-PCI Reversible Bridge (1b21:1080, rev 01 & 03)
+ *   AMD/ATI SBx00 PCI to PCI Bridge (1002:4384, rev 40)
+ */
+static bool pci_ext_cfg_is_aliased(struct pci_dev *dev)
+{
+#ifdef CONFIG_PCI_QUIRKS
+	int pos, ret;
+	u32 header, tmp;
+
+	pci_read_config_dword(dev, PCI_VENDOR_ID, &header);
+
+	for (pos = PCI_CFG_SPACE_SIZE;
+	     pos < PCI_CFG_SPACE_EXP_SIZE; pos += PCI_CFG_SPACE_SIZE) {
+		ret = pci_read_config_dword(dev, pos, &tmp);
+		if ((ret != PCIBIOS_SUCCESSFUL) || (header != tmp))
+			return false;
+	}
+
+	return true;
+#else
+	return false;
+#endif
+}
+
+/**
+ * pci_cfg_space_size_ext - Get the configuration space size of the PCI device
+ * @dev: PCI device
+ *
+ * Regular PCI devices have 256 bytes, but PCI-X 2 and PCI Express devices
+ * have 4096 bytes.  Even if the device is capable, that doesn't mean we can
+ * access it.  Maybe we don't have a way to generate extended config space
+ * accesses, or the device is behind a reverse Express bridge.  So we try
+ * reading the dword at 0x100 which must either be 0 or a valid extended
+ * capability header.
+ */
+static int pci_cfg_space_size_ext(struct pci_dev *dev)
+{
+	u32 status;
+	int pos = PCI_CFG_SPACE_SIZE;
+
+	if (pci_read_config_dword(dev, pos, &status) != PCIBIOS_SUCCESSFUL)
+		return PCI_CFG_SPACE_SIZE;
+	if (PCI_POSSIBLE_ERROR(status) || pci_ext_cfg_is_aliased(dev))
+		return PCI_CFG_SPACE_SIZE;
+
+	return PCI_CFG_SPACE_EXP_SIZE;
+}
+
+int pci_cfg_space_size(struct pci_dev *dev)
+{
+	int pos;
+	u32 status;
+	u16 class;
+
+#ifdef CONFIG_PCI_IOV
+	/*
+	 * Per the SR-IOV specification (rev 1.1, sec 3.5), VFs are required to
+	 * implement a PCIe capability and therefore must implement extended
+	 * config space.  We can skip the NO_EXTCFG test below and the
+	 * reachability/aliasing test in pci_cfg_space_size_ext() by virtue of
+	 * the fact that the SR-IOV capability on the PF resides in extended
+	 * config space and must be accessible and non-aliased to have enabled
+	 * support for this VF.  This is a micro performance optimization for
+	 * systems supporting many VFs.
+	 */
+	if (dev->is_virtfn)
+		return PCI_CFG_SPACE_EXP_SIZE;
+#endif
+
+	if (dev->bus->bus_flags & PCI_BUS_FLAGS_NO_EXTCFG)
+		return PCI_CFG_SPACE_SIZE;
+
+	class = dev->class >> 8;
+	if (class == PCI_CLASS_BRIDGE_HOST)
+		return pci_cfg_space_size_ext(dev);
+
+	if (pci_is_pcie(dev))
+		return pci_cfg_space_size_ext(dev);
+
+	pos = pci_find_capability(dev, PCI_CAP_ID_PCIX);
+	if (!pos)
+		return PCI_CFG_SPACE_SIZE;
+
+	pci_read_config_dword(dev, pos + PCI_X_STATUS, &status);
+	if (status & (PCI_X_STATUS_266MHZ | PCI_X_STATUS_533MHZ))
+		return pci_cfg_space_size_ext(dev);
+
+	return PCI_CFG_SPACE_SIZE;
+}
+
+static u32 pci_class(struct pci_dev *dev)
+{
+	u32 class;
+
+#ifdef CONFIG_PCI_IOV
+	if (dev->is_virtfn)
+		return dev->physfn->sriov->class;
+#endif
+	pci_read_config_dword(dev, PCI_CLASS_REVISION, &class);
+	return class;
+}
+
+static void pci_subsystem_ids(struct pci_dev *dev, u16 *vendor, u16 *device)
+{
+#ifdef CONFIG_PCI_IOV
+	if (dev->is_virtfn) {
+		*vendor = dev->physfn->sriov->subsystem_vendor;
+		*device = dev->physfn->sriov->subsystem_device;
+		return;
+	}
+#endif
+	pci_read_config_word(dev, PCI_SUBSYSTEM_VENDOR_ID, vendor);
+	pci_read_config_word(dev, PCI_SUBSYSTEM_ID, device);
+}
+
+static u8 pci_hdr_type(struct pci_dev *dev)
+{
+	u8 hdr_type;
+
+#ifdef CONFIG_PCI_IOV
+	if (dev->is_virtfn)
+		return dev->physfn->sriov->hdr_type;
+#endif
+	pci_read_config_byte(dev, PCI_HEADER_TYPE, &hdr_type);
+	return hdr_type;
+}
+
+#define LEGACY_IO_RESOURCE	(IORESOURCE_IO | IORESOURCE_PCI_FIXED)
+
+/**
+ * pci_intx_mask_broken - Test PCI_COMMAND_INTX_DISABLE writability
+ * @dev: PCI device
+ *
+ * Test whether PCI_COMMAND_INTX_DISABLE is writable for @dev.  Check this
+ * at enumeration-time to avoid modifying PCI_COMMAND at run-time.
+ */
+static int pci_intx_mask_broken(struct pci_dev *dev)
+{
+	u16 orig, toggle, new;
+
+	pci_read_config_word(dev, PCI_COMMAND, &orig);
+	toggle = orig ^ PCI_COMMAND_INTX_DISABLE;
+	pci_write_config_word(dev, PCI_COMMAND, toggle);
+	pci_read_config_word(dev, PCI_COMMAND, &new);
+
+	pci_write_config_word(dev, PCI_COMMAND, orig);
+
+	/*
+	 * PCI_COMMAND_INTX_DISABLE was reserved and read-only prior to PCI
+	 * r2.3, so strictly speaking, a device is not *broken* if it's not
+	 * writable.  But we'll live with the misnomer for now.
+	 */
+	if (new != toggle)
+		return 1;
+	return 0;
+}
+
+static void early_dump_pci_device(struct pci_dev *pdev)
+{
+	u32 value[256 / 4];
+	int i;
+
+	pci_info(pdev, "config space:\n");
+
+	for (i = 0; i < 256; i += 4)
+		pci_read_config_dword(pdev, i, &value[i / 4]);
+
+	print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 1,
+		       value, 256, false);
+}
+
+/**
+ * pci_setup_device - Fill in class and map information of a device
+ * @dev: the device structure to fill
+ *
+ * Initialize the device structure with information about the device's
+ * vendor,class,memory and IO-space addresses, IRQ lines etc.
+ * Called at initialisation of the PCI subsystem and by CardBus services.
+ * Returns 0 on success and negative if unknown type of device (not normal,
+ * bridge or CardBus).
+ */
+int pci_setup_device(struct pci_dev *dev)
+{
+	u32 class;
+	u16 cmd;
+	u8 hdr_type;
+	int pos = 0;
+	struct pci_bus_region region;
+	struct resource *res;
+
+	hdr_type = pci_hdr_type(dev);
+
+	dev->sysdata = dev->bus->sysdata;
+	dev->dev.parent = dev->bus->bridge;
+	dev->dev.bus = &pci_bus_type;
+	dev->hdr_type = hdr_type & 0x7f;
+	dev->multifunction = !!(hdr_type & 0x80);
+	dev->error_state = pci_channel_io_normal;
+	set_pcie_port_type(dev);
+
+	pci_set_of_node(dev);
+	pci_set_acpi_fwnode(dev);
+
+	pci_dev_assign_slot(dev);
+
+	/*
+	 * Assume 32-bit PCI; let 64-bit PCI cards (which are far rarer)
+	 * set this higher, assuming the system even supports it.
+	 */
+	dev->dma_mask = 0xffffffff;
+
+	dev_set_name(&dev->dev, "%04x:%02x:%02x.%d", pci_domain_nr(dev->bus),
+		     dev->bus->number, PCI_SLOT(dev->devfn),
+		     PCI_FUNC(dev->devfn));
+
+	class = pci_class(dev);
+
+	dev->revision = class & 0xff;
+	dev->class = class >> 8;		    /* upper 3 bytes */
+
+	if (pci_early_dump)
+		early_dump_pci_device(dev);
+
+	/* Need to have dev->class ready */
+	dev->cfg_size = pci_cfg_space_size(dev);
+
+	/* Need to have dev->cfg_size ready */
+	set_pcie_thunderbolt(dev);
+
+	set_pcie_untrusted(dev);
+
+	/* "Unknown power state" */
+	dev->current_state = PCI_UNKNOWN;
+
+	/* Early fixups, before probing the BARs */
+	pci_fixup_device(pci_fixup_early, dev);
+
+	pci_set_removable(dev);
+
+	pci_info(dev, "[%04x:%04x] type %02x class %#08x\n",
+		 dev->vendor, dev->device, dev->hdr_type, dev->class);
+
+	/* Device class may be changed after fixup */
+	class = dev->class >> 8;
+
+	if (dev->non_compliant_bars && !dev->mmio_always_on) {
+		pci_read_config_word(dev, PCI_COMMAND, &cmd);
+		if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
+			pci_info(dev, "device has non-compliant BARs; disabling IO/MEM decoding\n");
+			cmd &= ~PCI_COMMAND_IO;
+			cmd &= ~PCI_COMMAND_MEMORY;
+			pci_write_config_word(dev, PCI_COMMAND, cmd);
+		}
+	}
+
+	dev->broken_intx_masking = pci_intx_mask_broken(dev);
+
+	switch (dev->hdr_type) {		    /* header type */
+	case PCI_HEADER_TYPE_NORMAL:		    /* standard header */
+		if (class == PCI_CLASS_BRIDGE_PCI)
+			goto bad;
+		pci_read_irq(dev);
+		pci_read_bases(dev, 6, PCI_ROM_ADDRESS);
+
+		pci_subsystem_ids(dev, &dev->subsystem_vendor, &dev->subsystem_device);
+
+		/*
+		 * Do the ugly legacy mode stuff here rather than broken chip
+		 * quirk code. Legacy mode ATA controllers have fixed
+		 * addresses. These are not always echoed in BAR0-3, and
+		 * BAR0-3 in a few cases contain junk!
+		 */
+		if (class == PCI_CLASS_STORAGE_IDE) {
+			u8 progif;
+			pci_read_config_byte(dev, PCI_CLASS_PROG, &progif);
+			if ((progif & 1) == 0) {
+				region.start = 0x1F0;
+				region.end = 0x1F7;
+				res = &dev->resource[0];
+				res->flags = LEGACY_IO_RESOURCE;
+				pcibios_bus_to_resource(dev->bus, res, &region);
+				pci_info(dev, "legacy IDE quirk: reg 0x10: %pR\n",
+					 res);
+				region.start = 0x3F6;
+				region.end = 0x3F6;
+				res = &dev->resource[1];
+				res->flags = LEGACY_IO_RESOURCE;
+				pcibios_bus_to_resource(dev->bus, res, &region);
+				pci_info(dev, "legacy IDE quirk: reg 0x14: %pR\n",
+					 res);
+			}
+			if ((progif & 4) == 0) {
+				region.start = 0x170;
+				region.end = 0x177;
+				res = &dev->resource[2];
+				res->flags = LEGACY_IO_RESOURCE;
+				pcibios_bus_to_resource(dev->bus, res, &region);
+				pci_info(dev, "legacy IDE quirk: reg 0x18: %pR\n",
+					 res);
+				region.start = 0x376;
+				region.end = 0x376;
+				res = &dev->resource[3];
+				res->flags = LEGACY_IO_RESOURCE;
+				pcibios_bus_to_resource(dev->bus, res, &region);
+				pci_info(dev, "legacy IDE quirk: reg 0x1c: %pR\n",
+					 res);
+			}
+		}
+		break;
+
+	case PCI_HEADER_TYPE_BRIDGE:		    /* bridge header */
+		/*
+		 * The PCI-to-PCI bridge spec requires that subtractive
+		 * decoding (i.e. transparent) bridge must have programming
+		 * interface code of 0x01.
+		 */
+		pci_read_irq(dev);
+		dev->transparent = ((dev->class & 0xff) == 1);
+		pci_read_bases(dev, 2, PCI_ROM_ADDRESS1);
+		pci_read_bridge_windows(dev);
+		set_pcie_hotplug_bridge(dev);
+		pos = pci_find_capability(dev, PCI_CAP_ID_SSVID);
+		if (pos) {
+			pci_read_config_word(dev, pos + PCI_SSVID_VENDOR_ID, &dev->subsystem_vendor);
+			pci_read_config_word(dev, pos + PCI_SSVID_DEVICE_ID, &dev->subsystem_device);
+		}
+		break;
+
+	case PCI_HEADER_TYPE_CARDBUS:		    /* CardBus bridge header */
+		if (class != PCI_CLASS_BRIDGE_CARDBUS)
+			goto bad;
+		pci_read_irq(dev);
+		pci_read_bases(dev, 1, 0);
+		pci_read_config_word(dev, PCI_CB_SUBSYSTEM_VENDOR_ID, &dev->subsystem_vendor);
+		pci_read_config_word(dev, PCI_CB_SUBSYSTEM_ID, &dev->subsystem_device);
+		break;
+
+	default:				    /* unknown header */
+		pci_err(dev, "unknown header type %02x, ignoring device\n",
+			dev->hdr_type);
+		pci_release_of_node(dev);
+		return -EIO;
+
+	bad:
+		pci_err(dev, "ignoring class %#08x (doesn't match header type %02x)\n",
+			dev->class, dev->hdr_type);
+		dev->class = PCI_CLASS_NOT_DEFINED << 8;
+	}
+
+	/* We found a fine healthy device, go go go... */
+	return 0;
+}
+
+static void pci_configure_mps(struct pci_dev *dev)
+{
+	struct pci_dev *bridge = pci_upstream_bridge(dev);
+	int mps, mpss, p_mps, rc;
+
+	if (!pci_is_pcie(dev))
+		return;
+
+	/* MPS and MRRS fields are of type 'RsvdP' for VFs, short-circuit out */
+	if (dev->is_virtfn)
+		return;
+
+	/*
+	 * For Root Complex Integrated Endpoints, program the maximum
+	 * supported value unless limited by the PCIE_BUS_PEER2PEER case.
+	 */
+	if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) {
+		if (pcie_bus_config == PCIE_BUS_PEER2PEER)
+			mps = 128;
+		else
+			mps = 128 << dev->pcie_mpss;
+		rc = pcie_set_mps(dev, mps);
+		if (rc) {
+			pci_warn(dev, "can't set Max Payload Size to %d; if necessary, use \"pci=pcie_bus_safe\" and report a bug\n",
+				 mps);
+		}
+		return;
+	}
+
+	if (!bridge || !pci_is_pcie(bridge))
+		return;
+
+	mps = pcie_get_mps(dev);
+	p_mps = pcie_get_mps(bridge);
+
+	if (mps == p_mps)
+		return;
+
+	if (pcie_bus_config == PCIE_BUS_TUNE_OFF) {
+		pci_warn(dev, "Max Payload Size %d, but upstream %s set to %d; if necessary, use \"pci=pcie_bus_safe\" and report a bug\n",
+			 mps, pci_name(bridge), p_mps);
+		return;
+	}
+
+	/*
+	 * Fancier MPS configuration is done later by
+	 * pcie_bus_configure_settings()
+	 */
+	if (pcie_bus_config != PCIE_BUS_DEFAULT)
+		return;
+
+	mpss = 128 << dev->pcie_mpss;
+	if (mpss < p_mps && pci_pcie_type(bridge) == PCI_EXP_TYPE_ROOT_PORT) {
+		pcie_set_mps(bridge, mpss);
+		pci_info(dev, "Upstream bridge's Max Payload Size set to %d (was %d, max %d)\n",
+			 mpss, p_mps, 128 << bridge->pcie_mpss);
+		p_mps = pcie_get_mps(bridge);
+	}
+
+	rc = pcie_set_mps(dev, p_mps);
+	if (rc) {
+		pci_warn(dev, "can't set Max Payload Size to %d; if necessary, use \"pci=pcie_bus_safe\" and report a bug\n",
+			 p_mps);
+		return;
+	}
+
+	pci_info(dev, "Max Payload Size set to %d (was %d, max %d)\n",
+		 p_mps, mps, mpss);
+}
+
+int pci_configure_extended_tags(struct pci_dev *dev, void *ign)
+{
+	struct pci_host_bridge *host;
+	u32 cap;
+	u16 ctl;
+	int ret;
+
+	if (!pci_is_pcie(dev))
+		return 0;
+
+	ret = pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
+	if (ret)
+		return 0;
+
+	if (!(cap & PCI_EXP_DEVCAP_EXT_TAG))
+		return 0;
+
+	ret = pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &ctl);
+	if (ret)
+		return 0;
+
+	host = pci_find_host_bridge(dev->bus);
+	if (!host)
+		return 0;
+
+	/*
+	 * If some device in the hierarchy doesn't handle Extended Tags
+	 * correctly, make sure they're disabled.
+	 */
+	if (host->no_ext_tags) {
+		if (ctl & PCI_EXP_DEVCTL_EXT_TAG) {
+			pci_info(dev, "disabling Extended Tags\n");
+			pcie_capability_clear_word(dev, PCI_EXP_DEVCTL,
+						   PCI_EXP_DEVCTL_EXT_TAG);
+		}
+		return 0;
+	}
+
+	if (!(ctl & PCI_EXP_DEVCTL_EXT_TAG)) {
+		pci_info(dev, "enabling Extended Tags\n");
+		pcie_capability_set_word(dev, PCI_EXP_DEVCTL,
+					 PCI_EXP_DEVCTL_EXT_TAG);
+	}
+	return 0;
+}
+
+/**
+ * pcie_relaxed_ordering_enabled - Probe for PCIe relaxed ordering enable
+ * @dev: PCI device to query
+ *
+ * Returns true if the device has enabled relaxed ordering attribute.
+ */
+bool pcie_relaxed_ordering_enabled(struct pci_dev *dev)
+{
+	u16 v;
+
+	pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &v);
+
+	return !!(v & PCI_EXP_DEVCTL_RELAX_EN);
+}
+EXPORT_SYMBOL(pcie_relaxed_ordering_enabled);
+
+static void pci_configure_relaxed_ordering(struct pci_dev *dev)
+{
+	struct pci_dev *root;
+
+	/* PCI_EXP_DEVICE_RELAX_EN is RsvdP in VFs */
+	if (dev->is_virtfn)
+		return;
+
+	if (!pcie_relaxed_ordering_enabled(dev))
+		return;
+
+	/*
+	 * For now, we only deal with Relaxed Ordering issues with Root
+	 * Ports. Peer-to-Peer DMA is another can of worms.
+	 */
+	root = pcie_find_root_port(dev);
+	if (!root)
+		return;
+
+	if (root->dev_flags & PCI_DEV_FLAGS_NO_RELAXED_ORDERING) {
+		pcie_capability_clear_word(dev, PCI_EXP_DEVCTL,
+					   PCI_EXP_DEVCTL_RELAX_EN);
+		pci_info(dev, "Relaxed Ordering disabled because the Root Port didn't support it\n");
+	}
+}
+
+static void pci_configure_ltr(struct pci_dev *dev)
+{
+#ifdef CONFIG_PCIEASPM
+	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
+	struct pci_dev *bridge;
+	u32 cap, ctl;
+
+	if (!pci_is_pcie(dev))
+		return;
+
+	/* Read L1 PM substate capabilities */
+	dev->l1ss = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_L1SS);
+
+	pcie_capability_read_dword(dev, PCI_EXP_DEVCAP2, &cap);
+	if (!(cap & PCI_EXP_DEVCAP2_LTR))
+		return;
+
+	pcie_capability_read_dword(dev, PCI_EXP_DEVCTL2, &ctl);
+	if (ctl & PCI_EXP_DEVCTL2_LTR_EN) {
+		if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) {
+			dev->ltr_path = 1;
+			return;
+		}
+
+		bridge = pci_upstream_bridge(dev);
+		if (bridge && bridge->ltr_path)
+			dev->ltr_path = 1;
+
+		return;
+	}
+
+	if (!host->native_ltr)
+		return;
+
+	/*
+	 * Software must not enable LTR in an Endpoint unless the Root
+	 * Complex and all intermediate Switches indicate support for LTR.
+	 * PCIe r4.0, sec 6.18.
+	 */
+	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) {
+		pcie_capability_set_word(dev, PCI_EXP_DEVCTL2,
+					 PCI_EXP_DEVCTL2_LTR_EN);
+		dev->ltr_path = 1;
+		return;
+	}
+
+	/*
+	 * If we're configuring a hot-added device, LTR was likely
+	 * disabled in the upstream bridge, so re-enable it before enabling
+	 * it in the new device.
+	 */
+	bridge = pci_upstream_bridge(dev);
+	if (bridge && bridge->ltr_path) {
+		pci_bridge_reconfigure_ltr(dev);
+		pcie_capability_set_word(dev, PCI_EXP_DEVCTL2,
+					 PCI_EXP_DEVCTL2_LTR_EN);
+		dev->ltr_path = 1;
+	}
+#endif
+}
+
+static void pci_configure_eetlp_prefix(struct pci_dev *dev)
+{
+#ifdef CONFIG_PCI_PASID
+	struct pci_dev *bridge;
+	int pcie_type;
+	u32 cap;
+
+	if (!pci_is_pcie(dev))
+		return;
+
+	pcie_capability_read_dword(dev, PCI_EXP_DEVCAP2, &cap);
+	if (!(cap & PCI_EXP_DEVCAP2_EE_PREFIX))
+		return;
+
+	pcie_type = pci_pcie_type(dev);
+	if (pcie_type == PCI_EXP_TYPE_ROOT_PORT ||
+	    pcie_type == PCI_EXP_TYPE_RC_END)
+		dev->eetlp_prefix_path = 1;
+	else {
+		bridge = pci_upstream_bridge(dev);
+		if (bridge && bridge->eetlp_prefix_path)
+			dev->eetlp_prefix_path = 1;
+	}
+#endif
+}
+
+static void pci_configure_serr(struct pci_dev *dev)
+{
+	u16 control;
+
+	if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
+
+		/*
+		 * A bridge will not forward ERR_ messages coming from an
+		 * endpoint unless SERR# forwarding is enabled.
+		 */
+		pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &control);
+		if (!(control & PCI_BRIDGE_CTL_SERR)) {
+			control |= PCI_BRIDGE_CTL_SERR;
+			pci_write_config_word(dev, PCI_BRIDGE_CONTROL, control);
+		}
+	}
+}
+
+static void pci_configure_device(struct pci_dev *dev)
+{
+	pci_configure_mps(dev);
+	pci_configure_extended_tags(dev, NULL);
+	pci_configure_relaxed_ordering(dev);
+	pci_configure_ltr(dev);
+	pci_configure_eetlp_prefix(dev);
+	pci_configure_serr(dev);
+
+	pci_acpi_program_hp_params(dev);
+}
+
+static void pci_release_capabilities(struct pci_dev *dev)
+{
+	pci_aer_exit(dev);
+	pci_rcec_exit(dev);
+	pci_iov_release(dev);
+	pci_free_cap_save_buffers(dev);
+}
+
+/**
+ * pci_release_dev - Free a PCI device structure when all users of it are
+ *		     finished
+ * @dev: device that's been disconnected
+ *
+ * Will be called only by the device core when all users of this PCI device are
+ * done.
+ */
+static void pci_release_dev(struct device *dev)
+{
+	struct pci_dev *pci_dev;
+
+	pci_dev = to_pci_dev(dev);
+	pci_release_capabilities(pci_dev);
+	pci_release_of_node(pci_dev);
+	pcibios_release_device(pci_dev);
+	pci_bus_put(pci_dev->bus);
+	kfree(pci_dev->driver_override);
+	bitmap_free(pci_dev->dma_alias_mask);
+	dev_dbg(dev, "device released\n");
+	kfree(pci_dev);
+}
+
+struct pci_dev *pci_alloc_dev(struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+
+	dev = kzalloc(sizeof(struct pci_dev), GFP_KERNEL);
+	if (!dev)
+		return NULL;
+
+	INIT_LIST_HEAD(&dev->bus_list);
+	dev->dev.type = &pci_dev_type;
+	dev->bus = pci_bus_get(bus);
+	dev->driver_exclusive_resource = (struct resource) {
+		.name = "PCI Exclusive",
+		.start = 0,
+		.end = -1,
+	};
+
+	spin_lock_init(&dev->pcie_cap_lock);
+#ifdef CONFIG_PCI_MSI
+	raw_spin_lock_init(&dev->msi_lock);
+#endif
+	return dev;
+}
+EXPORT_SYMBOL(pci_alloc_dev);
+
+static bool pci_bus_crs_vendor_id(u32 l)
+{
+	return (l & 0xffff) == PCI_VENDOR_ID_PCI_SIG;
+}
+
+static bool pci_bus_wait_crs(struct pci_bus *bus, int devfn, u32 *l,
+			     int timeout)
+{
+	int delay = 1;
+
+	if (!pci_bus_crs_vendor_id(*l))
+		return true;	/* not a CRS completion */
+
+	if (!timeout)
+		return false;	/* CRS, but caller doesn't want to wait */
+
+	/*
+	 * We got the reserved Vendor ID that indicates a completion with
+	 * Configuration Request Retry Status (CRS).  Retry until we get a
+	 * valid Vendor ID or we time out.
+	 */
+	while (pci_bus_crs_vendor_id(*l)) {
+		if (delay > timeout) {
+			pr_warn("pci %04x:%02x:%02x.%d: not ready after %dms; giving up\n",
+				pci_domain_nr(bus), bus->number,
+				PCI_SLOT(devfn), PCI_FUNC(devfn), delay - 1);
+
+			return false;
+		}
+		if (delay >= 1000)
+			pr_info("pci %04x:%02x:%02x.%d: not ready after %dms; waiting\n",
+				pci_domain_nr(bus), bus->number,
+				PCI_SLOT(devfn), PCI_FUNC(devfn), delay - 1);
+
+		msleep(delay);
+		delay *= 2;
+
+		if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, l))
+			return false;
+	}
+
+	if (delay >= 1000)
+		pr_info("pci %04x:%02x:%02x.%d: ready after %dms\n",
+			pci_domain_nr(bus), bus->number,
+			PCI_SLOT(devfn), PCI_FUNC(devfn), delay - 1);
+
+	return true;
+}
+
+bool pci_bus_generic_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
+					int timeout)
+{
+	if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, l))
+		return false;
+
+	/* Some broken boards return 0 or ~0 (PCI_ERROR_RESPONSE) if a slot is empty: */
+	if (PCI_POSSIBLE_ERROR(*l) || *l == 0x00000000 ||
+	    *l == 0x0000ffff || *l == 0xffff0000)
+		return false;
+
+	if (pci_bus_crs_vendor_id(*l))
+		return pci_bus_wait_crs(bus, devfn, l, timeout);
+
+	return true;
+}
+
+bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
+				int timeout)
+{
+#ifdef CONFIG_PCI_QUIRKS
+	struct pci_dev *bridge = bus->self;
+
+	/*
+	 * Certain IDT switches have an issue where they improperly trigger
+	 * ACS Source Validation errors on completions for config reads.
+	 */
+	if (bridge && bridge->vendor == PCI_VENDOR_ID_IDT &&
+	    bridge->device == 0x80b5)
+		return pci_idt_bus_quirk(bus, devfn, l, timeout);
+#endif
+
+	return pci_bus_generic_read_dev_vendor_id(bus, devfn, l, timeout);
+}
+EXPORT_SYMBOL(pci_bus_read_dev_vendor_id);
+
+/*
+ * Read the config data for a PCI device, sanity-check it,
+ * and fill in the dev structure.
+ */
+static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
+{
+	struct pci_dev *dev;
+	u32 l;
+
+	if (!pci_bus_read_dev_vendor_id(bus, devfn, &l, 60*1000))
+		return NULL;
+
+	dev = pci_alloc_dev(bus);
+	if (!dev)
+		return NULL;
+
+	dev->devfn = devfn;
+	dev->vendor = l & 0xffff;
+	dev->device = (l >> 16) & 0xffff;
+
+	if (pci_setup_device(dev)) {
+		pci_bus_put(dev->bus);
+		kfree(dev);
+		return NULL;
+	}
+
+	return dev;
+}
+
+void pcie_report_downtraining(struct pci_dev *dev)
+{
+	if (!pci_is_pcie(dev))
+		return;
+
+	/* Look from the device up to avoid downstream ports with no devices */
+	if ((pci_pcie_type(dev) != PCI_EXP_TYPE_ENDPOINT) &&
+	    (pci_pcie_type(dev) != PCI_EXP_TYPE_LEG_END) &&
+	    (pci_pcie_type(dev) != PCI_EXP_TYPE_UPSTREAM))
+		return;
+
+	/* Multi-function PCIe devices share the same link/status */
+	if (PCI_FUNC(dev->devfn) != 0 || dev->is_virtfn)
+		return;
+
+	/* Print link status only if the device is constrained by the fabric */
+	__pcie_print_link_status(dev, false);
+}
+
+static void pci_init_capabilities(struct pci_dev *dev)
+{
+	pci_ea_init(dev);		/* Enhanced Allocation */
+	pci_msi_init(dev);		/* Disable MSI */
+	pci_msix_init(dev);		/* Disable MSI-X */
+
+	/* Buffers for saving PCIe and PCI-X capabilities */
+	pci_allocate_cap_save_buffers(dev);
+
+	pci_pm_init(dev);		/* Power Management */
+	pci_vpd_init(dev);		/* Vital Product Data */
+	pci_configure_ari(dev);		/* Alternative Routing-ID Forwarding */
+	pci_iov_init(dev);		/* Single Root I/O Virtualization */
+	pci_ats_init(dev);		/* Address Translation Services */
+	pci_pri_init(dev);		/* Page Request Interface */
+	pci_pasid_init(dev);		/* Process Address Space ID */
+	pci_acs_init(dev);		/* Access Control Services */
+	pci_ptm_init(dev);		/* Precision Time Measurement */
+	pci_aer_init(dev);		/* Advanced Error Reporting */
+	pci_dpc_init(dev);		/* Downstream Port Containment */
+	pci_rcec_init(dev);		/* Root Complex Event Collector */
+
+	pcie_report_downtraining(dev);
+	pci_init_reset_methods(dev);
+}
+
+/*
+ * This is the equivalent of pci_host_bridge_msi_domain() that acts on
+ * devices. Firmware interfaces that can select the MSI domain on a
+ * per-device basis should be called from here.
+ */
+static struct irq_domain *pci_dev_msi_domain(struct pci_dev *dev)
+{
+	struct irq_domain *d;
+
+	/*
+	 * If a domain has been set through the pcibios_device_add()
+	 * callback, then this is the one (platform code knows best).
+	 */
+	d = dev_get_msi_domain(&dev->dev);
+	if (d)
+		return d;
+
+	/*
+	 * Let's see if we have a firmware interface able to provide
+	 * the domain.
+	 */
+	d = pci_msi_get_device_domain(dev);
+	if (d)
+		return d;
+
+	return NULL;
+}
+
+static void pci_set_msi_domain(struct pci_dev *dev)
+{
+	struct irq_domain *d;
+
+	/*
+	 * If the platform or firmware interfaces cannot supply a
+	 * device-specific MSI domain, then inherit the default domain
+	 * from the host bridge itself.
+	 */
+	d = pci_dev_msi_domain(dev);
+	if (!d)
+		d = dev_get_msi_domain(&dev->bus->dev);
+
+	dev_set_msi_domain(&dev->dev, d);
+}
+
+void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
+{
+	int ret;
+
+	pci_configure_device(dev);
+
+	device_initialize(&dev->dev);
+	dev->dev.release = pci_release_dev;
+
+	set_dev_node(&dev->dev, pcibus_to_node(bus));
+	dev->dev.dma_mask = &dev->dma_mask;
+	dev->dev.dma_parms = &dev->dma_parms;
+	dev->dev.coherent_dma_mask = 0xffffffffull;
+
+	dma_set_max_seg_size(&dev->dev, 65536);
+	dma_set_seg_boundary(&dev->dev, 0xffffffff);
+
+	/* Fix up broken headers */
+	pci_fixup_device(pci_fixup_header, dev);
+
+	pci_reassigndev_resource_alignment(dev);
+
+	dev->state_saved = false;
+
+	pci_init_capabilities(dev);
+
+	/*
+	 * Add the device to our list of discovered devices
+	 * and the bus list for fixup functions, etc.
+	 */
+	down_write(&pci_bus_sem);
+	list_add_tail(&dev->bus_list, &bus->devices);
+	up_write(&pci_bus_sem);
+
+	ret = pcibios_device_add(dev);
+	WARN_ON(ret < 0);
+
+	/* Set up MSI IRQ domain */
+	pci_set_msi_domain(dev);
+
+	/* Notifier could use PCI capabilities */
+	dev->match_driver = false;
+	ret = device_add(&dev->dev);
+	WARN_ON(ret < 0);
+}
+
+struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn)
+{
+	struct pci_dev *dev;
+
+	dev = pci_get_slot(bus, devfn);
+	if (dev) {
+		pci_dev_put(dev);
+		return dev;
+	}
+
+	dev = pci_scan_device(bus, devfn);
+	if (!dev)
+		return NULL;
+
+	pci_device_add(dev, bus);
+
+	return dev;
+}
+EXPORT_SYMBOL(pci_scan_single_device);
+
+static int next_ari_fn(struct pci_bus *bus, struct pci_dev *dev, int fn)
+{
+	int pos;
+	u16 cap = 0;
+	unsigned int next_fn;
+
+	if (!dev)
+		return -ENODEV;
+
+	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI);
+	if (!pos)
+		return -ENODEV;
+
+	pci_read_config_word(dev, pos + PCI_ARI_CAP, &cap);
+	next_fn = PCI_ARI_CAP_NFN(cap);
+	if (next_fn <= fn)
+		return -ENODEV;	/* protect against malformed list */
+
+	return next_fn;
+}
+
+static int next_fn(struct pci_bus *bus, struct pci_dev *dev, int fn)
+{
+	if (pci_ari_enabled(bus))
+		return next_ari_fn(bus, dev, fn);
+
+	if (fn >= 7)
+		return -ENODEV;
+	/* only multifunction devices may have more functions */
+	if (dev && !dev->multifunction)
+		return -ENODEV;
+
+	return fn + 1;
+}
+
+static int only_one_child(struct pci_bus *bus)
+{
+	struct pci_dev *bridge = bus->self;
+
+	/*
+	 * Systems with unusual topologies set PCI_SCAN_ALL_PCIE_DEVS so
+	 * we scan for all possible devices, not just Device 0.
+	 */
+	if (pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
+		return 0;
+
+	/*
+	 * A PCIe Downstream Port normally leads to a Link with only Device
+	 * 0 on it (PCIe spec r3.1, sec 7.3.1).  As an optimization, scan
+	 * only for Device 0 in that situation.
+	 */
+	if (bridge && pci_is_pcie(bridge) && pcie_downstream_port(bridge))
+		return 1;
+
+	return 0;
+}
+
+/**
+ * pci_scan_slot - Scan a PCI slot on a bus for devices
+ * @bus: PCI bus to scan
+ * @devfn: slot number to scan (must have zero function)
+ *
+ * Scan a PCI slot on the specified PCI bus for devices, adding
+ * discovered devices to the @bus->devices list.  New devices
+ * will not have is_added set.
+ *
+ * Returns the number of new devices found.
+ */
+int pci_scan_slot(struct pci_bus *bus, int devfn)
+{
+	struct pci_dev *dev;
+	int fn = 0, nr = 0;
+
+	if (only_one_child(bus) && (devfn > 0))
+		return 0; /* Already scanned the entire slot */
+
+	do {
+		dev = pci_scan_single_device(bus, devfn + fn);
+		if (dev) {
+			if (!pci_dev_is_added(dev))
+				nr++;
+			if (fn > 0)
+				dev->multifunction = 1;
+		} else if (fn == 0) {
+			/*
+			 * Function 0 is required unless we are running on
+			 * a hypervisor that passes through individual PCI
+			 * functions.
+			 */
+			if (!hypervisor_isolated_pci_functions())
+				break;
+		}
+		fn = next_fn(bus, dev, fn);
+	} while (fn >= 0);
+
+	/* Only one slot has PCIe device */
+	if (bus->self && nr)
+		pcie_aspm_init_link_state(bus->self);
+
+	return nr;
+}
+EXPORT_SYMBOL(pci_scan_slot);
+
+static int pcie_find_smpss(struct pci_dev *dev, void *data)
+{
+	u8 *smpss = data;
+
+	if (!pci_is_pcie(dev))
+		return 0;
+
+	/*
+	 * We don't have a way to change MPS settings on devices that have
+	 * drivers attached.  A hot-added device might support only the minimum
+	 * MPS setting (MPS=128).  Therefore, if the fabric contains a bridge
+	 * where devices may be hot-added, we limit the fabric MPS to 128 so
+	 * hot-added devices will work correctly.
+	 *
+	 * However, if we hot-add a device to a slot directly below a Root
+	 * Port, it's impossible for there to be other existing devices below
+	 * the port.  We don't limit the MPS in this case because we can
+	 * reconfigure MPS on both the Root Port and the hot-added device,
+	 * and there are no other devices involved.
+	 *
+	 * Note that this PCIE_BUS_SAFE path assumes no peer-to-peer DMA.
+	 */
+	if (dev->is_hotplug_bridge &&
+	    pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT)
+		*smpss = 0;
+
+	if (*smpss > dev->pcie_mpss)
+		*smpss = dev->pcie_mpss;
+
+	return 0;
+}
+
+static void pcie_write_mps(struct pci_dev *dev, int mps)
+{
+	int rc;
+
+	if (pcie_bus_config == PCIE_BUS_PERFORMANCE) {
+		mps = 128 << dev->pcie_mpss;
+
+		if (pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT &&
+		    dev->bus->self)
+
+			/*
+			 * For "Performance", the assumption is made that
+			 * downstream communication will never be larger than
+			 * the MRRS.  So, the MPS only needs to be configured
+			 * for the upstream communication.  This being the case,
+			 * walk from the top down and set the MPS of the child
+			 * to that of the parent bus.
+			 *
+			 * Configure the device MPS with the smaller of the
+			 * device MPSS or the bridge MPS (which is assumed to be
+			 * properly configured at this point to the largest
+			 * allowable MPS based on its parent bus).
+			 */
+			mps = min(mps, pcie_get_mps(dev->bus->self));
+	}
+
+	rc = pcie_set_mps(dev, mps);
+	if (rc)
+		pci_err(dev, "Failed attempting to set the MPS\n");
+}
+
+static void pcie_write_mrrs(struct pci_dev *dev)
+{
+	int rc, mrrs;
+
+	/*
+	 * In the "safe" case, do not configure the MRRS.  There appear to be
+	 * issues with setting MRRS to 0 on a number of devices.
+	 */
+	if (pcie_bus_config != PCIE_BUS_PERFORMANCE)
+		return;
+
+	/*
+	 * For max performance, the MRRS must be set to the largest supported
+	 * value.  However, it cannot be configured larger than the MPS the
+	 * device or the bus can support.  This should already be properly
+	 * configured by a prior call to pcie_write_mps().
+	 */
+	mrrs = pcie_get_mps(dev);
+
+	/*
+	 * MRRS is a R/W register.  Invalid values can be written, but a
+	 * subsequent read will verify if the value is acceptable or not.
+	 * If the MRRS value provided is not acceptable (e.g., too large),
+	 * shrink the value until it is acceptable to the HW.
+	 */
+	while (mrrs != pcie_get_readrq(dev) && mrrs >= 128) {
+		rc = pcie_set_readrq(dev, mrrs);
+		if (!rc)
+			break;
+
+		pci_warn(dev, "Failed attempting to set the MRRS\n");
+		mrrs /= 2;
+	}
+
+	if (mrrs < 128)
+		pci_err(dev, "MRRS was unable to be configured with a safe value.  If problems are experienced, try running with pci=pcie_bus_safe\n");
+}
+
+static int pcie_bus_configure_set(struct pci_dev *dev, void *data)
+{
+	int mps, orig_mps;
+
+	if (!pci_is_pcie(dev))
+		return 0;
+
+	if (pcie_bus_config == PCIE_BUS_TUNE_OFF ||
+	    pcie_bus_config == PCIE_BUS_DEFAULT)
+		return 0;
+
+	mps = 128 << *(u8 *)data;
+	orig_mps = pcie_get_mps(dev);
+
+	pcie_write_mps(dev, mps);
+	pcie_write_mrrs(dev);
+
+	pci_info(dev, "Max Payload Size set to %4d/%4d (was %4d), Max Read Rq %4d\n",
+		 pcie_get_mps(dev), 128 << dev->pcie_mpss,
+		 orig_mps, pcie_get_readrq(dev));
+
+	return 0;
+}
+
+/*
+ * pcie_bus_configure_settings() requires that pci_walk_bus work in a top-down,
+ * parents then children fashion.  If this changes, then this code will not
+ * work as designed.
+ */
+void pcie_bus_configure_settings(struct pci_bus *bus)
+{
+	u8 smpss = 0;
+
+	if (!bus->self)
+		return;
+
+	if (!pci_is_pcie(bus->self))
+		return;
+
+	/*
+	 * FIXME - Peer to peer DMA is possible, though the endpoint would need
+	 * to be aware of the MPS of the destination.  To work around this,
+	 * simply force the MPS of the entire system to the smallest possible.
+	 */
+	if (pcie_bus_config == PCIE_BUS_PEER2PEER)
+		smpss = 0;
+
+	if (pcie_bus_config == PCIE_BUS_SAFE) {
+		smpss = bus->self->pcie_mpss;
+
+		pcie_find_smpss(bus->self, &smpss);
+		pci_walk_bus(bus, pcie_find_smpss, &smpss);
+	}
+
+	pcie_bus_configure_set(bus->self, &smpss);
+	pci_walk_bus(bus, pcie_bus_configure_set, &smpss);
+}
+EXPORT_SYMBOL_GPL(pcie_bus_configure_settings);
+
+/*
+ * Called after each bus is probed, but before its children are examined.  This
+ * is marked as __weak because multiple architectures define it.
+ */
+void __weak pcibios_fixup_bus(struct pci_bus *bus)
+{
+       /* nothing to do, expected to be removed in the future */
+}
+
+/**
+ * pci_scan_child_bus_extend() - Scan devices below a bus
+ * @bus: Bus to scan for devices
+ * @available_buses: Total number of buses available (%0 does not try to
+ *		     extend beyond the minimal)
+ *
+ * Scans devices below @bus including subordinate buses. Returns new
+ * subordinate number including all the found devices. Passing
+ * @available_buses causes the remaining bus space to be distributed
+ * equally between hotplug-capable bridges to allow future extension of the
+ * hierarchy.
+ */
+static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
+					      unsigned int available_buses)
+{
+	unsigned int used_buses, normal_bridges = 0, hotplug_bridges = 0;
+	unsigned int start = bus->busn_res.start;
+	unsigned int devfn, cmax, max = start;
+	struct pci_dev *dev;
+
+	dev_dbg(&bus->dev, "scanning bus\n");
+
+	/* Go find them, Rover! */
+	for (devfn = 0; devfn < 256; devfn += 8)
+		pci_scan_slot(bus, devfn);
+
+	/* Reserve buses for SR-IOV capability */
+	used_buses = pci_iov_bus_range(bus);
+	max += used_buses;
+
+	/*
+	 * After performing arch-dependent fixup of the bus, look behind
+	 * all PCI-to-PCI bridges on this bus.
+	 */
+	if (!bus->is_added) {
+		dev_dbg(&bus->dev, "fixups for bus\n");
+		pcibios_fixup_bus(bus);
+		bus->is_added = 1;
+	}
+
+	/*
+	 * Calculate how many hotplug bridges and normal bridges there
+	 * are on this bus. We will distribute the additional available
+	 * buses between hotplug bridges.
+	 */
+	for_each_pci_bridge(dev, bus) {
+		if (dev->is_hotplug_bridge)
+			hotplug_bridges++;
+		else
+			normal_bridges++;
+	}
+
+	/*
+	 * Scan bridges that are already configured. We don't touch them
+	 * unless they are misconfigured (which will be done in the second
+	 * scan below).
+	 */
+	for_each_pci_bridge(dev, bus) {
+		cmax = max;
+		max = pci_scan_bridge_extend(bus, dev, max, 0, 0);
+
+		/*
+		 * Reserve one bus for each bridge now to avoid extending
+		 * hotplug bridges too much during the second scan below.
+		 */
+		used_buses++;
+		if (max - cmax > 1)
+			used_buses += max - cmax - 1;
+	}
+
+	/* Scan bridges that need to be reconfigured */
+	for_each_pci_bridge(dev, bus) {
+		unsigned int buses = 0;
+
+		if (!hotplug_bridges && normal_bridges == 1) {
+			/*
+			 * There is only one bridge on the bus (upstream
+			 * port) so it gets all available buses which it
+			 * can then distribute to the possible hotplug
+			 * bridges below.
+			 */
+			buses = available_buses;
+		} else if (dev->is_hotplug_bridge) {
+			/*
+			 * Distribute the extra buses between hotplug
+			 * bridges if any.
+			 */
+			buses = available_buses / hotplug_bridges;
+			buses = min(buses, available_buses - used_buses + 1);
+		}
+
+		cmax = max;
+		max = pci_scan_bridge_extend(bus, dev, cmax, buses, 1);
+		/* One bus is already accounted so don't add it again */
+		if (max - cmax > 1)
+			used_buses += max - cmax - 1;
+	}
+
+	/*
+	 * Make sure a hotplug bridge has at least the minimum requested
+	 * number of buses but allow it to grow up to the maximum available
+	 * bus number if there is room.
+	 */
+	if (bus->self && bus->self->is_hotplug_bridge) {
+		used_buses = max_t(unsigned int, available_buses,
+				   pci_hotplug_bus_size - 1);
+		if (max - start < used_buses) {
+			max = start + used_buses;
+
+			/* Do not allocate more buses than we have room left */
+			if (max > bus->busn_res.end)
+				max = bus->busn_res.end;
+
+			dev_dbg(&bus->dev, "%pR extended by %#02x\n",
+				&bus->busn_res, max - start);
+		}
+	}
+
+	/*
+	 * We've scanned the bus and so we know all about what's on
+	 * the other side of any bridges that may be on this bus plus
+	 * any devices.
+	 *
+	 * Return how far we've got finding sub-buses.
+	 */
+	dev_dbg(&bus->dev, "bus scan returning with max=%02x\n", max);
+	return max;
+}
+
+/**
+ * pci_scan_child_bus() - Scan devices below a bus
+ * @bus: Bus to scan for devices
+ *
+ * Scans devices below @bus including subordinate buses. Returns new
+ * subordinate number including all the found devices.
+ */
+unsigned int pci_scan_child_bus(struct pci_bus *bus)
+{
+	return pci_scan_child_bus_extend(bus, 0);
+}
+EXPORT_SYMBOL_GPL(pci_scan_child_bus);
+
+/**
+ * pcibios_root_bridge_prepare - Platform-specific host bridge setup
+ * @bridge: Host bridge to set up
+ *
+ * Default empty implementation.  Replace with an architecture-specific setup
+ * routine, if necessary.
+ */
+int __weak pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
+{
+	return 0;
+}
+
+void __weak pcibios_add_bus(struct pci_bus *bus)
+{
+}
+
+void __weak pcibios_remove_bus(struct pci_bus *bus)
+{
+}
+
+struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
+		struct pci_ops *ops, void *sysdata, struct list_head *resources)
+{
+	int error;
+	struct pci_host_bridge *bridge;
+
+	bridge = pci_alloc_host_bridge(0);
+	if (!bridge)
+		return NULL;
+
+	bridge->dev.parent = parent;
+
+	list_splice_init(resources, &bridge->windows);
+	bridge->sysdata = sysdata;
+	bridge->busnr = bus;
+	bridge->ops = ops;
+
+	error = pci_register_host_bridge(bridge);
+	if (error < 0)
+		goto err_out;
+
+	return bridge->bus;
+
+err_out:
+	put_device(&bridge->dev);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(pci_create_root_bus);
+
+int pci_host_probe(struct pci_host_bridge *bridge)
+{
+	struct pci_bus *bus, *child;
+	int ret;
+
+	ret = pci_scan_root_bus_bridge(bridge);
+	if (ret < 0) {
+		dev_err(bridge->dev.parent, "Scanning root bridge failed");
+		return ret;
+	}
+
+	bus = bridge->bus;
+
+	/*
+	 * We insert PCI resources into the iomem_resource and
+	 * ioport_resource trees in either pci_bus_claim_resources()
+	 * or pci_bus_assign_resources().
+	 */
+	if (pci_has_flag(PCI_PROBE_ONLY)) {
+		pci_bus_claim_resources(bus);
+	} else {
+		pci_bus_size_bridges(bus);
+		pci_bus_assign_resources(bus);
+
+		list_for_each_entry(child, &bus->children, node)
+			pcie_bus_configure_settings(child);
+	}
+
+	pci_bus_add_devices(bus);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pci_host_probe);
+
+int pci_bus_insert_busn_res(struct pci_bus *b, int bus, int bus_max)
+{
+	struct resource *res = &b->busn_res;
+	struct resource *parent_res, *conflict;
+
+	res->start = bus;
+	res->end = bus_max;
+	res->flags = IORESOURCE_BUS;
+
+	if (!pci_is_root_bus(b))
+		parent_res = &b->parent->busn_res;
+	else {
+		parent_res = get_pci_domain_busn_res(pci_domain_nr(b));
+		res->flags |= IORESOURCE_PCI_FIXED;
+	}
+
+	conflict = request_resource_conflict(parent_res, res);
+
+	if (conflict)
+		dev_info(&b->dev,
+			   "busn_res: can not insert %pR under %s%pR (conflicts with %s %pR)\n",
+			    res, pci_is_root_bus(b) ? "domain " : "",
+			    parent_res, conflict->name, conflict);
+
+	return conflict == NULL;
+}
+
+int pci_bus_update_busn_res_end(struct pci_bus *b, int bus_max)
+{
+	struct resource *res = &b->busn_res;
+	struct resource old_res = *res;
+	resource_size_t size;
+	int ret;
+
+	if (res->start > bus_max)
+		return -EINVAL;
+
+	size = bus_max - res->start + 1;
+	ret = adjust_resource(res, res->start, size);
+	dev_info(&b->dev, "busn_res: %pR end %s updated to %02x\n",
+			&old_res, ret ? "can not be" : "is", bus_max);
+
+	if (!ret && !res->parent)
+		pci_bus_insert_busn_res(b, res->start, res->end);
+
+	return ret;
+}
+
+void pci_bus_release_busn_res(struct pci_bus *b)
+{
+	struct resource *res = &b->busn_res;
+	int ret;
+
+	if (!res->flags || !res->parent)
+		return;
+
+	ret = release_resource(res);
+	dev_info(&b->dev, "busn_res: %pR %s released\n",
+			res, ret ? "can not be" : "is");
+}
+
+int pci_scan_root_bus_bridge(struct pci_host_bridge *bridge)
+{
+	struct resource_entry *window;
+	bool found = false;
+	struct pci_bus *b;
+	int max, bus, ret;
+
+	if (!bridge)
+		return -EINVAL;
+
+	resource_list_for_each_entry(window, &bridge->windows)
+		if (window->res->flags & IORESOURCE_BUS) {
+			bridge->busnr = window->res->start;
+			found = true;
+			break;
+		}
+
+	ret = pci_register_host_bridge(bridge);
+	if (ret < 0)
+		return ret;
+
+	b = bridge->bus;
+	bus = bridge->busnr;
+
+	if (!found) {
+		dev_info(&b->dev,
+		 "No busn resource found for root bus, will use [bus %02x-ff]\n",
+			bus);
+		pci_bus_insert_busn_res(b, bus, 255);
+	}
+
+	max = pci_scan_child_bus(b);
+
+	if (!found)
+		pci_bus_update_busn_res_end(b, max);
+
+	return 0;
+}
+EXPORT_SYMBOL(pci_scan_root_bus_bridge);
+
+struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
+		struct pci_ops *ops, void *sysdata, struct list_head *resources)
+{
+	struct resource_entry *window;
+	bool found = false;
+	struct pci_bus *b;
+	int max;
+
+	resource_list_for_each_entry(window, resources)
+		if (window->res->flags & IORESOURCE_BUS) {
+			found = true;
+			break;
+		}
+
+	b = pci_create_root_bus(parent, bus, ops, sysdata, resources);
+	if (!b)
+		return NULL;
+
+	if (!found) {
+		dev_info(&b->dev,
+		 "No busn resource found for root bus, will use [bus %02x-ff]\n",
+			bus);
+		pci_bus_insert_busn_res(b, bus, 255);
+	}
+
+	max = pci_scan_child_bus(b);
+
+	if (!found)
+		pci_bus_update_busn_res_end(b, max);
+
+	return b;
+}
+EXPORT_SYMBOL(pci_scan_root_bus);
+
+struct pci_bus *pci_scan_bus(int bus, struct pci_ops *ops,
+					void *sysdata)
+{
+	LIST_HEAD(resources);
+	struct pci_bus *b;
+
+	pci_add_resource(&resources, &ioport_resource);
+	pci_add_resource(&resources, &iomem_resource);
+	pci_add_resource(&resources, &busn_resource);
+	b = pci_create_root_bus(NULL, bus, ops, sysdata, &resources);
+	if (b) {
+		pci_scan_child_bus(b);
+	} else {
+		pci_free_resource_list(&resources);
+	}
+	return b;
+}
+EXPORT_SYMBOL(pci_scan_bus);
+
+/**
+ * pci_rescan_bus_bridge_resize - Scan a PCI bus for devices
+ * @bridge: PCI bridge for the bus to scan
+ *
+ * Scan a PCI bus and child buses for new devices, add them,
+ * and enable them, resizing bridge mmio/io resource if necessary
+ * and possible.  The caller must ensure the child devices are already
+ * removed for resizing to occur.
+ *
+ * Returns the max number of subordinate bus discovered.
+ */
+unsigned int pci_rescan_bus_bridge_resize(struct pci_dev *bridge)
+{
+	unsigned int max;
+	struct pci_bus *bus = bridge->subordinate;
+
+	max = pci_scan_child_bus(bus);
+
+	pci_assign_unassigned_bridge_resources(bridge);
+
+	pci_bus_add_devices(bus);
+
+	return max;
+}
+
+/**
+ * pci_rescan_bus - Scan a PCI bus for devices
+ * @bus: PCI bus to scan
+ *
+ * Scan a PCI bus and child buses for new devices, add them,
+ * and enable them.
+ *
+ * Returns the max number of subordinate bus discovered.
+ */
+unsigned int pci_rescan_bus(struct pci_bus *bus)
+{
+	unsigned int max;
+
+	max = pci_scan_child_bus(bus);
+	pci_assign_unassigned_bus_resources(bus);
+	pci_bus_add_devices(bus);
+
+	return max;
+}
+EXPORT_SYMBOL_GPL(pci_rescan_bus);
+
+/*
+ * pci_rescan_bus(), pci_rescan_bus_bridge_resize() and PCI device removal
+ * routines should always be executed under this mutex.
+ */
+static DEFINE_MUTEX(pci_rescan_remove_lock);
+
+void pci_lock_rescan_remove(void)
+{
+	mutex_lock(&pci_rescan_remove_lock);
+}
+EXPORT_SYMBOL_GPL(pci_lock_rescan_remove);
+
+void pci_unlock_rescan_remove(void)
+{
+	mutex_unlock(&pci_rescan_remove_lock);
+}
+EXPORT_SYMBOL_GPL(pci_unlock_rescan_remove);
+
+static int __init pci_sort_bf_cmp(const struct device *d_a,
+				  const struct device *d_b)
+{
+	const struct pci_dev *a = to_pci_dev(d_a);
+	const struct pci_dev *b = to_pci_dev(d_b);
+
+	if      (pci_domain_nr(a->bus) < pci_domain_nr(b->bus)) return -1;
+	else if (pci_domain_nr(a->bus) > pci_domain_nr(b->bus)) return  1;
+
+	if      (a->bus->number < b->bus->number) return -1;
+	else if (a->bus->number > b->bus->number) return  1;
+
+	if      (a->devfn < b->devfn) return -1;
+	else if (a->devfn > b->devfn) return  1;
+
+	return 0;
+}
+
+void __init pci_sort_breadthfirst(void)
+{
+	bus_sort_breadthfirst(&pci_bus_type, &pci_sort_bf_cmp);
+}
+
+int pci_hp_add_bridge(struct pci_dev *dev)
+{
+	struct pci_bus *parent = dev->bus;
+	int busnr, start = parent->busn_res.start;
+	unsigned int available_buses = 0;
+	int end = parent->busn_res.end;
+
+	for (busnr = start; busnr <= end; busnr++) {
+		if (!pci_find_bus(pci_domain_nr(parent), busnr))
+			break;
+	}
+	if (busnr-- > end) {
+		pci_err(dev, "No bus number available for hot-added bridge\n");
+		return -1;
+	}
+
+	/* Scan bridges that are already configured */
+	busnr = pci_scan_bridge(parent, dev, busnr, 0);
+
+	/*
+	 * Distribute the available bus numbers between hotplug-capable
+	 * bridges to make extending the chain later possible.
+	 */
+	available_buses = end - busnr;
+
+	/* Scan bridges that need to be reconfigured */
+	pci_scan_bridge_extend(parent, dev, busnr, available_buses, 1);
+
+	if (!dev->subordinate)
+		return -1;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pci_hp_add_bridge);