arch/powerpc/platforms/pseries/pci.c - linux - Git at Google

 /*
  * Copyright (C) 2001 Dave Engebretsen, IBM Corporation
  * Copyright (C) 2003 Anton Blanchard <anton@au.ibm.com>, IBM
  *
  * pSeries specific routines for PCI.
  *
  * 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; either version 2 of the License, or
  * (at your option) any later version.
  *
  * 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.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  */

 #include <linux/init.h>
 #include <linux/ioport.h>
 #include <linux/kernel.h>
 #include <linux/pci.h>
 #include <linux/string.h>

 #include <asm/eeh.h>
 #include <asm/pci-bridge.h>
 #include <asm/prom.h>
 #include <asm/ppc-pci.h>
 #include <asm/pci.h>
 #include "pseries.h"

 #if 0
 void pcibios_name_device(struct pci_dev *dev)
 {
 	struct device_node *dn;

 	/*
 	 * Add IBM loc code (slot) as a prefix to the device names for service
 	 */
 	dn = pci_device_to_OF_node(dev);
 	if (dn) {
 		const char *loc_code = of_get_property(dn, "ibm,loc-code",
 				NULL);
 		if (loc_code) {
 			int loc_len = strlen(loc_code);
 			if (loc_len < sizeof(dev->dev.name)) {
 				memmove(dev->dev.name+loc_len+1, dev->dev.name,
 					sizeof(dev->dev.name)-loc_len-1);
 				memcpy(dev->dev.name, loc_code, loc_len);
 				dev->dev.name[loc_len] = ' ';
 				dev->dev.name[sizeof(dev->dev.name)-1] = '\0';
 			}
 		}
 	}
 }
 DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, pcibios_name_device);
 #endif

 #ifdef CONFIG_PCI_IOV
 #define MAX_VFS_FOR_MAP_PE 256
 struct pe_map_bar_entry {
 	__be64     bar;       /* Input:  Virtual Function BAR */
 	__be16     rid;       /* Input:  Virtual Function Router ID */
 	__be16     pe_num;    /* Output: Virtual Function PE Number */
 	__be32     reserved;  /* Reserved Space */
 };

 int pseries_send_map_pe(struct pci_dev *pdev,
 			u16 num_vfs,
 			struct pe_map_bar_entry *vf_pe_array)
 {
 	struct pci_dn *pdn;
 	int rc;
 	unsigned long buid, addr;
 	int ibm_map_pes = rtas_token("ibm,open-sriov-map-pe-number");

 	if (ibm_map_pes == RTAS_UNKNOWN_SERVICE)
 		return -EINVAL;

 	pdn = pci_get_pdn(pdev);
 	addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
 	buid = pdn->phb->buid;
 	spin_lock(&rtas_data_buf_lock);
 	memcpy(rtas_data_buf, vf_pe_array,
 	       RTAS_DATA_BUF_SIZE);
 	rc = rtas_call(ibm_map_pes, 5, 1, NULL, addr,
 		       BUID_HI(buid), BUID_LO(buid),
 		       rtas_data_buf,
 		       num_vfs * sizeof(struct pe_map_bar_entry));
 	memcpy(vf_pe_array, rtas_data_buf, RTAS_DATA_BUF_SIZE);
 	spin_unlock(&rtas_data_buf_lock);

 	if (rc)
 		dev_err(&pdev->dev,
 			"%s: Failed to associate pes PE#%lx, rc=%x\n",
 			__func__,  addr, rc);

 	return rc;
 }

 void pseries_set_pe_num(struct pci_dev *pdev, u16 vf_index, __be16 pe_num)
 {
 	struct pci_dn *pdn;

 	pdn = pci_get_pdn(pdev);
 	pdn->pe_num_map[vf_index] = be16_to_cpu(pe_num);
 	dev_dbg(&pdev->dev, "VF %04x:%02x:%02x.%x associated with PE#%x\n",
 		pci_domain_nr(pdev->bus),
 		pdev->bus->number,
 		PCI_SLOT(pci_iov_virtfn_devfn(pdev, vf_index)),
 		PCI_FUNC(pci_iov_virtfn_devfn(pdev, vf_index)),
 		pdn->pe_num_map[vf_index]);
 }

 int pseries_associate_pes(struct pci_dev *pdev, u16 num_vfs)
 {
 	struct pci_dn *pdn;
 	int i, rc, vf_index;
 	struct pe_map_bar_entry *vf_pe_array;
 	struct resource *res;
 	u64 size;

 	vf_pe_array = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
 	if (!vf_pe_array)
 		return -ENOMEM;

 	pdn = pci_get_pdn(pdev);
 	/* create firmware structure to associate pes */
 	for (vf_index = 0; vf_index < num_vfs; vf_index++) {
 		pdn->pe_num_map[vf_index] = IODA_INVALID_PE;
 		for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 			res = &pdev->resource[i + PCI_IOV_RESOURCES];
 			if (!res->parent)
 				continue;
 			size = pcibios_iov_resource_alignment(pdev, i +
 					PCI_IOV_RESOURCES);
 			vf_pe_array[vf_index].bar =
 				cpu_to_be64(res->start + size * vf_index);
 			vf_pe_array[vf_index].rid =
 				cpu_to_be16((pci_iov_virtfn_bus(pdev, vf_index)
 					    << 8) | pci_iov_virtfn_devfn(pdev,
 					    vf_index));
 			vf_pe_array[vf_index].pe_num =
 				cpu_to_be16(IODA_INVALID_PE);
 		}
 	}

 	rc = pseries_send_map_pe(pdev, num_vfs, vf_pe_array);
 	/* Only zero is success */
 	if (!rc)
 		for (vf_index = 0; vf_index < num_vfs; vf_index++)
 			pseries_set_pe_num(pdev, vf_index,
 					   vf_pe_array[vf_index].pe_num);

 	kfree(vf_pe_array);
 	return rc;
 }

 int pseries_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
 {
 	struct pci_dn         *pdn;
 	int                    rc;
 	const int *max_vfs;
 	int max_config_vfs;
 	struct device_node *dn = pci_device_to_OF_node(pdev);

 	max_vfs = of_get_property(dn, "ibm,number-of-configurable-vfs", NULL);

 	if (!max_vfs)
 		return -EINVAL;

 	/* First integer stores max config */
 	max_config_vfs = of_read_number(&max_vfs[0], 1);
 	if (max_config_vfs < num_vfs && num_vfs > MAX_VFS_FOR_MAP_PE) {
 		dev_err(&pdev->dev,
 			"Num VFs %x > %x Configurable VFs\n",
 			num_vfs, (num_vfs > MAX_VFS_FOR_MAP_PE) ?
 			MAX_VFS_FOR_MAP_PE : max_config_vfs);
 		return -EINVAL;
 	}

 	pdn = pci_get_pdn(pdev);
 	pdn->pe_num_map = kmalloc_array(num_vfs,
 					sizeof(*pdn->pe_num_map),
 					GFP_KERNEL);
 	if (!pdn->pe_num_map)
 		return -ENOMEM;

 	rc = pseries_associate_pes(pdev, num_vfs);

 	/* Anything other than zero is failure */
 	if (rc) {
 		dev_err(&pdev->dev, "Failure to enable sriov: %x\n", rc);
 		kfree(pdn->pe_num_map);
 	} else {
 		pci_vf_drivers_autoprobe(pdev, false);
 	}

 	return rc;
 }

 int pseries_pcibios_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
 {
 	/* Allocate PCI data */
 	add_dev_pci_data(pdev);
 	return pseries_pci_sriov_enable(pdev, num_vfs);
 }

 int pseries_pcibios_sriov_disable(struct pci_dev *pdev)
 {
 	struct pci_dn         *pdn;

 	pdn = pci_get_pdn(pdev);
 	/* Releasing pe_num_map */
 	kfree(pdn->pe_num_map);
 	/* Release PCI data */
 	remove_dev_pci_data(pdev);
 	pci_vf_drivers_autoprobe(pdev, true);
 	return 0;
 }
 #endif

 static void __init pSeries_request_regions(void)
 {
 	if (!isa_io_base)
 		return;

 	request_region(0x20,0x20,"pic1");
 	request_region(0xa0,0x20,"pic2");
 	request_region(0x00,0x20,"dma1");
 	request_region(0x40,0x20,"timer");
 	request_region(0x80,0x10,"dma page reg");
 	request_region(0xc0,0x20,"dma2");
 }

 void __init pSeries_final_fixup(void)
 {
 	struct pci_controller *hose;

 	pSeries_request_regions();

 	eeh_probe_devices();
 	eeh_addr_cache_build();

 #ifdef CONFIG_PCI_IOV
 	ppc_md.pcibios_sriov_enable = pseries_pcibios_sriov_enable;
 	ppc_md.pcibios_sriov_disable = pseries_pcibios_sriov_disable;
 #endif
 	list_for_each_entry(hose, &hose_list, list_node) {
 		struct device_node *dn = hose->dn, *nvdn;

 		while (1) {
 			dn = of_find_all_nodes(dn);
 			if (!dn)
 				break;
 			nvdn = of_parse_phandle(dn, "ibm,nvlink", 0);
 			if (!nvdn)
 				continue;
 			if (!of_device_is_compatible(nvdn, "ibm,npu-link"))
 				continue;
 			if (!of_device_is_compatible(nvdn->parent,
 						"ibm,power9-npu"))
 				continue;
 #ifdef CONFIG_PPC_POWERNV
 			WARN_ON_ONCE(pnv_npu2_init(hose));
 #endif
 			break;
 		}
 	}
 }

 /*
  * Assume the winbond 82c105 is the IDE controller on a
  * p610/p615/p630. We should probably be more careful in case
  * someone tries to plug in a similar adapter.
  */
 static void fixup_winbond_82c105(struct pci_dev* dev)
 {
 	int i;
 	unsigned int reg;

 	if (!machine_is(pseries))
 		return;

 	printk("Using INTC for W82c105 IDE controller.\n");
 	pci_read_config_dword(dev, 0x40, &reg);
 	/* Enable LEGIRQ to use INTC instead of ISA interrupts */
 	pci_write_config_dword(dev, 0x40, reg | (1<<11));

 	for (i = 0; i < DEVICE_COUNT_RESOURCE; ++i) {
 		/* zap the 2nd function of the winbond chip */
 		if (dev->resource[i].flags & IORESOURCE_IO
 		    && dev->bus->number == 0 && dev->devfn == 0x81)
 			dev->resource[i].flags &= ~IORESOURCE_IO;
 		if (dev->resource[i].start == 0 && dev->resource[i].end) {
 			dev->resource[i].flags = 0;
 			dev->resource[i].end = 0;
 		}
 	}
 }
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND, PCI_DEVICE_ID_WINBOND_82C105,
 			 fixup_winbond_82c105);

 int pseries_root_bridge_prepare(struct pci_host_bridge *bridge)
 {
 	struct device_node *dn, *pdn;
 	struct pci_bus *bus;
 	u32 pcie_link_speed_stats[2];
 	int rc;

 	bus = bridge->bus;

 	/* Rely on the pcibios_free_controller_deferred() callback. */
 	pci_set_host_bridge_release(bridge, pcibios_free_controller_deferred,
 					(void *) pci_bus_to_host(bus));

 	dn = pcibios_get_phb_of_node(bus);
 	if (!dn)
 		return 0;

 	for (pdn = dn; pdn != NULL; pdn = of_get_next_parent(pdn)) {
 		rc = of_property_read_u32_array(pdn,
 				"ibm,pcie-link-speed-stats",
 				&pcie_link_speed_stats[0], 2);
 		if (!rc)
 			break;
 	}

 	of_node_put(pdn);

 	if (rc) {
 		pr_debug("no ibm,pcie-link-speed-stats property\n");
 		return 0;
 	}

 	switch (pcie_link_speed_stats[0]) {
 	case 0x01:
 		bus->max_bus_speed = PCIE_SPEED_2_5GT;
 		break;
 	case 0x02:
 		bus->max_bus_speed = PCIE_SPEED_5_0GT;
 		break;
 	case 0x04:
 		bus->max_bus_speed = PCIE_SPEED_8_0GT;
 		break;
 	default:
 		bus->max_bus_speed = PCI_SPEED_UNKNOWN;
 		break;
 	}

 	switch (pcie_link_speed_stats[1]) {
 	case 0x01:
 		bus->cur_bus_speed = PCIE_SPEED_2_5GT;
 		break;
 	case 0x02:
 		bus->cur_bus_speed = PCIE_SPEED_5_0GT;
 		break;
 	case 0x04:
 		bus->cur_bus_speed = PCIE_SPEED_8_0GT;
 		break;
 	default:
 		bus->cur_bus_speed = PCI_SPEED_UNKNOWN;
 		break;
 	}

 	return 0;
 }
	/*
	* Copyright (C) 2001 Dave Engebretsen, IBM Corporation
	* Copyright (C) 2003 Anton Blanchard <anton@au.ibm.com>, IBM
	*
	* pSeries specific routines for PCI.
	*
	* 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; either version 2 of the License, or
	* (at your option) any later version.
	*
	* 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.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

	#include <linux/init.h>
	#include <linux/ioport.h>
	#include <linux/kernel.h>
	#include <linux/pci.h>
	#include <linux/string.h>

	#include <asm/eeh.h>
	#include <asm/pci-bridge.h>
	#include <asm/prom.h>
	#include <asm/ppc-pci.h>
	#include <asm/pci.h>
	#include "pseries.h"

	#if 0
	void pcibios_name_device(struct pci_dev *dev)
	{
	struct device_node *dn;

	/*
	* Add IBM loc code (slot) as a prefix to the device names for service
	*/
	dn = pci_device_to_OF_node(dev);
	if (dn) {
	const char *loc_code = of_get_property(dn, "ibm,loc-code",
	NULL);
	if (loc_code) {
	int loc_len = strlen(loc_code);
	if (loc_len < sizeof(dev->dev.name)) {
	memmove(dev->dev.name+loc_len+1, dev->dev.name,
	sizeof(dev->dev.name)-loc_len-1);
	memcpy(dev->dev.name, loc_code, loc_len);
	dev->dev.name[loc_len] = ' ';
	dev->dev.name[sizeof(dev->dev.name)-1] = '\0';
	}
	}
	}
	}
	DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, pcibios_name_device);
	#endif

	#ifdef CONFIG_PCI_IOV
	#define MAX_VFS_FOR_MAP_PE 256
	struct pe_map_bar_entry {
	__be64 bar; /* Input: Virtual Function BAR */
	__be16 rid; /* Input: Virtual Function Router ID */
	__be16 pe_num; /* Output: Virtual Function PE Number */
	__be32 reserved; /* Reserved Space */
	};

	int pseries_send_map_pe(struct pci_dev *pdev,
	u16 num_vfs,
	struct pe_map_bar_entry *vf_pe_array)
	{
	struct pci_dn *pdn;
	int rc;
	unsigned long buid, addr;
	int ibm_map_pes = rtas_token("ibm,open-sriov-map-pe-number");

	if (ibm_map_pes == RTAS_UNKNOWN_SERVICE)
	return -EINVAL;

	pdn = pci_get_pdn(pdev);
	addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
	buid = pdn->phb->buid;
	spin_lock(&rtas_data_buf_lock);
	memcpy(rtas_data_buf, vf_pe_array,
	RTAS_DATA_BUF_SIZE);
	rc = rtas_call(ibm_map_pes, 5, 1, NULL, addr,
	BUID_HI(buid), BUID_LO(buid),
	rtas_data_buf,
	num_vfs * sizeof(struct pe_map_bar_entry));
	memcpy(vf_pe_array, rtas_data_buf, RTAS_DATA_BUF_SIZE);
	spin_unlock(&rtas_data_buf_lock);

	if (rc)
	dev_err(&pdev->dev,
	"%s: Failed to associate pes PE#%lx, rc=%x\n",
	__func__, addr, rc);

	return rc;
	}

	void pseries_set_pe_num(struct pci_dev *pdev, u16 vf_index, __be16 pe_num)
	{
	struct pci_dn *pdn;

	pdn = pci_get_pdn(pdev);
	pdn->pe_num_map[vf_index] = be16_to_cpu(pe_num);
	dev_dbg(&pdev->dev, "VF %04x:%02x:%02x.%x associated with PE#%x\n",
	pci_domain_nr(pdev->bus),
	pdev->bus->number,
	PCI_SLOT(pci_iov_virtfn_devfn(pdev, vf_index)),
	PCI_FUNC(pci_iov_virtfn_devfn(pdev, vf_index)),
	pdn->pe_num_map[vf_index]);
	}

	int pseries_associate_pes(struct pci_dev *pdev, u16 num_vfs)
	{
	struct pci_dn *pdn;
	int i, rc, vf_index;
	struct pe_map_bar_entry *vf_pe_array;
	struct resource *res;
	u64 size;

	vf_pe_array = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
	if (!vf_pe_array)
	return -ENOMEM;

	pdn = pci_get_pdn(pdev);
	/* create firmware structure to associate pes */
	for (vf_index = 0; vf_index < num_vfs; vf_index++) {
	pdn->pe_num_map[vf_index] = IODA_INVALID_PE;
	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
	res = &pdev->resource[i + PCI_IOV_RESOURCES];
	if (!res->parent)
	continue;
	size = pcibios_iov_resource_alignment(pdev, i +
	PCI_IOV_RESOURCES);
	vf_pe_array[vf_index].bar =
	cpu_to_be64(res->start + size * vf_index);
	vf_pe_array[vf_index].rid =
	cpu_to_be16((pci_iov_virtfn_bus(pdev, vf_index)
	<< 8) \| pci_iov_virtfn_devfn(pdev,
	vf_index));
	vf_pe_array[vf_index].pe_num =
	cpu_to_be16(IODA_INVALID_PE);
	}
	}

	rc = pseries_send_map_pe(pdev, num_vfs, vf_pe_array);
	/* Only zero is success */
	if (!rc)
	for (vf_index = 0; vf_index < num_vfs; vf_index++)
	pseries_set_pe_num(pdev, vf_index,
	vf_pe_array[vf_index].pe_num);

	kfree(vf_pe_array);
	return rc;
	}

	int pseries_pci_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
	{
	struct pci_dn *pdn;
	int rc;
	const int *max_vfs;
	int max_config_vfs;
	struct device_node *dn = pci_device_to_OF_node(pdev);

	max_vfs = of_get_property(dn, "ibm,number-of-configurable-vfs", NULL);

	if (!max_vfs)
	return -EINVAL;

	/* First integer stores max config */
	max_config_vfs = of_read_number(&max_vfs[0], 1);
	if (max_config_vfs < num_vfs && num_vfs > MAX_VFS_FOR_MAP_PE) {
	dev_err(&pdev->dev,
	"Num VFs %x > %x Configurable VFs\n",
	num_vfs, (num_vfs > MAX_VFS_FOR_MAP_PE) ?
	MAX_VFS_FOR_MAP_PE : max_config_vfs);
	return -EINVAL;
	}

	pdn = pci_get_pdn(pdev);
	pdn->pe_num_map = kmalloc_array(num_vfs,
	sizeof(*pdn->pe_num_map),
	GFP_KERNEL);
	if (!pdn->pe_num_map)
	return -ENOMEM;

	rc = pseries_associate_pes(pdev, num_vfs);

	/* Anything other than zero is failure */
	if (rc) {
	dev_err(&pdev->dev, "Failure to enable sriov: %x\n", rc);
	kfree(pdn->pe_num_map);
	} else {
	pci_vf_drivers_autoprobe(pdev, false);
	}

	return rc;
	}

	int pseries_pcibios_sriov_enable(struct pci_dev *pdev, u16 num_vfs)
	{
	/* Allocate PCI data */
	add_dev_pci_data(pdev);
	return pseries_pci_sriov_enable(pdev, num_vfs);
	}

	int pseries_pcibios_sriov_disable(struct pci_dev *pdev)
	{
	struct pci_dn *pdn;

	pdn = pci_get_pdn(pdev);
	/* Releasing pe_num_map */
	kfree(pdn->pe_num_map);
	/* Release PCI data */
	remove_dev_pci_data(pdev);
	pci_vf_drivers_autoprobe(pdev, true);
	return 0;
	}
	#endif

	static void __init pSeries_request_regions(void)
	{
	if (!isa_io_base)
	return;

	request_region(0x20,0x20,"pic1");
	request_region(0xa0,0x20,"pic2");
	request_region(0x00,0x20,"dma1");
	request_region(0x40,0x20,"timer");
	request_region(0x80,0x10,"dma page reg");
	request_region(0xc0,0x20,"dma2");
	}

	void __init pSeries_final_fixup(void)
	{
	struct pci_controller *hose;

	pSeries_request_regions();

	eeh_probe_devices();
	eeh_addr_cache_build();

	#ifdef CONFIG_PCI_IOV
	ppc_md.pcibios_sriov_enable = pseries_pcibios_sriov_enable;
	ppc_md.pcibios_sriov_disable = pseries_pcibios_sriov_disable;
	#endif
	list_for_each_entry(hose, &hose_list, list_node) {
	struct device_node dn = hose->dn, nvdn;

	while (1) {
	dn = of_find_all_nodes(dn);
	if (!dn)
	break;
	nvdn = of_parse_phandle(dn, "ibm,nvlink", 0);
	if (!nvdn)
	continue;
	if (!of_device_is_compatible(nvdn, "ibm,npu-link"))
	continue;
	if (!of_device_is_compatible(nvdn->parent,
	"ibm,power9-npu"))
	continue;
	#ifdef CONFIG_PPC_POWERNV
	WARN_ON_ONCE(pnv_npu2_init(hose));
	#endif
	break;
	}
	}
	}

	/*
	* Assume the winbond 82c105 is the IDE controller on a
	* p610/p615/p630. We should probably be more careful in case
	* someone tries to plug in a similar adapter.
	*/
	static void fixup_winbond_82c105(struct pci_dev* dev)
	{
	int i;
	unsigned int reg;

	if (!machine_is(pseries))
	return;

	printk("Using INTC for W82c105 IDE controller.\n");
	pci_read_config_dword(dev, 0x40, &reg);
	/* Enable LEGIRQ to use INTC instead of ISA interrupts */
	pci_write_config_dword(dev, 0x40, reg \| (1<<11));

	for (i = 0; i < DEVICE_COUNT_RESOURCE; ++i) {
	/* zap the 2nd function of the winbond chip */
	if (dev->resource[i].flags & IORESOURCE_IO
	&& dev->bus->number == 0 && dev->devfn == 0x81)
	dev->resource[i].flags &= ~IORESOURCE_IO;
	if (dev->resource[i].start == 0 && dev->resource[i].end) {
	dev->resource[i].flags = 0;
	dev->resource[i].end = 0;
	}
	}
	}
	DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND, PCI_DEVICE_ID_WINBOND_82C105,
	fixup_winbond_82c105);

	int pseries_root_bridge_prepare(struct pci_host_bridge *bridge)
	{
	struct device_node dn, pdn;
	struct pci_bus *bus;
	u32 pcie_link_speed_stats[2];
	int rc;

	bus = bridge->bus;

	/* Rely on the pcibios_free_controller_deferred() callback. */
	pci_set_host_bridge_release(bridge, pcibios_free_controller_deferred,
	(void *) pci_bus_to_host(bus));

	dn = pcibios_get_phb_of_node(bus);
	if (!dn)
	return 0;

	for (pdn = dn; pdn != NULL; pdn = of_get_next_parent(pdn)) {
	rc = of_property_read_u32_array(pdn,
	"ibm,pcie-link-speed-stats",
	&pcie_link_speed_stats[0], 2);
	if (!rc)
	break;
	}

	of_node_put(pdn);

	if (rc) {
	pr_debug("no ibm,pcie-link-speed-stats property\n");
	return 0;
	}

	switch (pcie_link_speed_stats[0]) {
	case 0x01:
	bus->max_bus_speed = PCIE_SPEED_2_5GT;
	break;
	case 0x02:
	bus->max_bus_speed = PCIE_SPEED_5_0GT;
	break;
	case 0x04:
	bus->max_bus_speed = PCIE_SPEED_8_0GT;
	break;
	default:
	bus->max_bus_speed = PCI_SPEED_UNKNOWN;
	break;
	}

	switch (pcie_link_speed_stats[1]) {
	case 0x01:
	bus->cur_bus_speed = PCIE_SPEED_2_5GT;
	break;
	case 0x02:
	bus->cur_bus_speed = PCIE_SPEED_5_0GT;
	break;
	case 0x04:
	bus->cur_bus_speed = PCIE_SPEED_8_0GT;
	break;
	default:
	bus->cur_bus_speed = PCI_SPEED_UNKNOWN;
	break;
	}

	return 0;
	}