4a5954ed77
In hotplug case, function pci_add_pci_devices() is called to rescan the specified PCI bus, which might not have any child devices. Access to the PCI bus's child device node will cause kernel crash without exception. This adds one more check to skip scanning PCI bus that doesn't have any subordinate devices from device-tree, in order to avoid kernel crash. Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
147 lines
4 KiB
C
147 lines
4 KiB
C
/*
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* Derived from "arch/powerpc/platforms/pseries/pci_dlpar.c"
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*
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* Copyright (C) 2003 Linda Xie <lxie@us.ibm.com>
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* Copyright (C) 2005 International Business Machines
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*
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* Updates, 2005, John Rose <johnrose@austin.ibm.com>
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* Updates, 2005, Linas Vepstas <linas@austin.ibm.com>
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* Updates, 2013, Gavin Shan <shangw@linux.vnet.ibm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/pci.h>
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#include <linux/export.h>
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#include <asm/pci-bridge.h>
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#include <asm/ppc-pci.h>
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#include <asm/firmware.h>
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#include <asm/eeh.h>
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static struct pci_bus *find_bus_among_children(struct pci_bus *bus,
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struct device_node *dn)
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{
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struct pci_bus *child = NULL;
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struct pci_bus *tmp;
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if (pci_bus_to_OF_node(bus) == dn)
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return bus;
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list_for_each_entry(tmp, &bus->children, node) {
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child = find_bus_among_children(tmp, dn);
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if (child)
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break;
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}
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return child;
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}
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struct pci_bus *pci_find_bus_by_node(struct device_node *dn)
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{
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struct pci_dn *pdn = PCI_DN(dn);
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if (!pdn || !pdn->phb || !pdn->phb->bus)
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return NULL;
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return find_bus_among_children(pdn->phb->bus, dn);
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}
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EXPORT_SYMBOL_GPL(pci_find_bus_by_node);
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/**
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* pcibios_release_device - release PCI device
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* @dev: PCI device
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*
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* The function is called before releasing the indicated PCI device.
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*/
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void pcibios_release_device(struct pci_dev *dev)
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{
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struct pci_controller *phb = pci_bus_to_host(dev->bus);
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eeh_remove_device(dev);
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if (phb->controller_ops.release_device)
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phb->controller_ops.release_device(dev);
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}
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/**
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* pci_hp_remove_devices - remove all devices under this bus
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* @bus: the indicated PCI bus
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*
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* Remove all of the PCI devices under this bus both from the
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* linux pci device tree, and from the powerpc EEH address cache.
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*/
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void pci_hp_remove_devices(struct pci_bus *bus)
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{
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struct pci_dev *dev, *tmp;
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struct pci_bus *child_bus;
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/* First go down child busses */
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list_for_each_entry(child_bus, &bus->children, node)
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pci_hp_remove_devices(child_bus);
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pr_debug("PCI: Removing devices on bus %04x:%02x\n",
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pci_domain_nr(bus), bus->number);
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list_for_each_entry_safe_reverse(dev, tmp, &bus->devices, bus_list) {
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pr_debug(" Removing %s...\n", pci_name(dev));
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pci_stop_and_remove_bus_device(dev);
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}
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}
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EXPORT_SYMBOL_GPL(pci_hp_remove_devices);
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/**
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* pci_hp_add_devices - adds new pci devices to bus
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* @bus: the indicated PCI bus
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*
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* This routine will find and fixup new pci devices under
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* the indicated bus. This routine presumes that there
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* might already be some devices under this bridge, so
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* it carefully tries to add only new devices. (And that
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* is how this routine differs from other, similar pcibios
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* routines.)
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*/
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void pci_hp_add_devices(struct pci_bus *bus)
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{
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int slotno, mode, pass, max;
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struct pci_dev *dev;
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struct pci_controller *phb;
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struct device_node *dn = pci_bus_to_OF_node(bus);
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eeh_add_device_tree_early(PCI_DN(dn));
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phb = pci_bus_to_host(bus);
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mode = PCI_PROBE_NORMAL;
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if (phb->controller_ops.probe_mode)
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mode = phb->controller_ops.probe_mode(bus);
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if (mode == PCI_PROBE_DEVTREE) {
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/* use ofdt-based probe */
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of_rescan_bus(dn, bus);
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} else if (mode == PCI_PROBE_NORMAL &&
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dn->child && PCI_DN(dn->child)) {
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/*
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* Use legacy probe. In the partial hotplug case, we
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* probably have grandchildren devices unplugged. So
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* we don't check the return value from pci_scan_slot() in
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* order for fully rescan all the way down to pick them up.
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* They can have been removed during partial hotplug.
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*/
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slotno = PCI_SLOT(PCI_DN(dn->child)->devfn);
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pci_scan_slot(bus, PCI_DEVFN(slotno, 0));
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pcibios_setup_bus_devices(bus);
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max = bus->busn_res.start;
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for (pass = 0; pass < 2; pass++) {
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list_for_each_entry(dev, &bus->devices, bus_list) {
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if (pci_is_bridge(dev))
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max = pci_scan_bridge(bus, dev,
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max, pass);
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}
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}
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}
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pcibios_finish_adding_to_bus(bus);
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}
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EXPORT_SYMBOL_GPL(pci_hp_add_devices);
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