arch/powerpc/kernel/pci-hotplug.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Derived from "arch/powerpc/platforms/pseries/pci_dlpar.c"
   4  *
   5  * Copyright (C) 2003 Linda Xie <lxie@us.ibm.com>
   6  * Copyright (C) 2005 International Business Machines
   7  *
   8  * Updates, 2005, John Rose <johnrose@austin.ibm.com>
   9  * Updates, 2005, Linas Vepstas <linas@austin.ibm.com>
  10  * Updates, 2013, Gavin Shan <shangw@linux.vnet.ibm.com>
  11  */
  12
  13 #include <linux/pci.h>
  14 #include <linux/export.h>
  15 #include <asm/pci-bridge.h>
  16 #include <asm/ppc-pci.h>
  17 #include <asm/firmware.h>
  18 #include <asm/eeh.h>
  19
  20 static struct pci_bus *find_bus_among_children(struct pci_bus *bus,
  21                                                struct device_node *dn)
  22 {
  23         struct pci_bus *child = NULL;
  24         struct pci_bus *tmp;
  25
  26         if (pci_bus_to_OF_node(bus) == dn)
  27                 return bus;
  28
  29         list_for_each_entry(tmp, &bus->children, node) {
  30                 child = find_bus_among_children(tmp, dn);
  31                 if (child)
  32                         break;
  33         }
  34
  35         return child;
  36 }
  37
  38 struct pci_bus *pci_find_bus_by_node(struct device_node *dn)
  39 {
  40         struct pci_dn *pdn = PCI_DN(dn);
  41
  42         if (!pdn  || !pdn->phb || !pdn->phb->bus)
  43                 return NULL;
  44
  45         return find_bus_among_children(pdn->phb->bus, dn);
  46 }
  47 EXPORT_SYMBOL_GPL(pci_find_bus_by_node);
  48
  49 /**
  50  * pcibios_release_device - release PCI device
  51  * @dev: PCI device
  52  *
  53  * The function is called before releasing the indicated PCI device.
  54  */
  55 void pcibios_release_device(struct pci_dev *dev)
  56 {
  57         struct pci_controller *phb = pci_bus_to_host(dev->bus);
  58         struct pci_dn *pdn = pci_get_pdn(dev);
  59
  60         if (phb->controller_ops.release_device)
  61                 phb->controller_ops.release_device(dev);
  62
  63         /* free()ing the pci_dn has been deferred to us, do it now */
  64         if (pdn && (pdn->flags & PCI_DN_FLAG_DEAD)) {
  65                 pci_dbg(dev, "freeing dead pdn\n");
  66                 kfree(pdn);
  67         }
  68 }
  69
  70 /**
  71  * pci_hp_remove_devices - remove all devices under this bus
  72  * @bus: the indicated PCI bus
  73  *
  74  * Remove all of the PCI devices under this bus both from the
  75  * linux pci device tree, and from the powerpc EEH address cache.
  76  */
  77 void pci_hp_remove_devices(struct pci_bus *bus)
  78 {
  79         struct pci_dev *dev, *tmp;
  80         struct pci_bus *child_bus;
  81
  82         /* First go down child busses */
  83         list_for_each_entry(child_bus, &bus->children, node)
  84                 pci_hp_remove_devices(child_bus);
  85
  86         pr_debug("PCI: Removing devices on bus %04x:%02x\n",
  87                  pci_domain_nr(bus),  bus->number);
  88         list_for_each_entry_safe_reverse(dev, tmp, &bus->devices, bus_list) {
  89                 pr_debug("   Removing %s...\n", pci_name(dev));
  90                 pci_stop_and_remove_bus_device(dev);
  91         }
  92 }
  93 EXPORT_SYMBOL_GPL(pci_hp_remove_devices);
  94
  95 /**
  96  * pci_hp_add_devices - adds new pci devices to bus
  97  * @bus: the indicated PCI bus
  98  *
  99  * This routine will find and fixup new pci devices under
 100  * the indicated bus. This routine presumes that there
 101  * might already be some devices under this bridge, so
 102  * it carefully tries to add only new devices.  (And that
 103  * is how this routine differs from other, similar pcibios
 104  * routines.)
 105  */
 106 void pci_hp_add_devices(struct pci_bus *bus)
 107 {
 108         int slotno, mode, max;
 109         struct pci_dev *dev;
 110         struct pci_controller *phb;
 111         struct device_node *dn = pci_bus_to_OF_node(bus);
 112
 113         phb = pci_bus_to_host(bus);
 114
 115         mode = PCI_PROBE_NORMAL;
 116         if (phb->controller_ops.probe_mode)
 117                 mode = phb->controller_ops.probe_mode(bus);
 118
 119         if (mode == PCI_PROBE_DEVTREE) {
 120                 /* use ofdt-based probe */
 121                 of_rescan_bus(dn, bus);
 122         } else if (mode == PCI_PROBE_NORMAL &&
 123                    dn->child && PCI_DN(dn->child)) {
 124                 /*
 125                  * Use legacy probe. In the partial hotplug case, we
 126                  * probably have grandchildren devices unplugged. So
 127                  * we don't check the return value from pci_scan_slot() in
 128                  * order for fully rescan all the way down to pick them up.
 129                  * They can have been removed during partial hotplug.
 130                  */
 131                 slotno = PCI_SLOT(PCI_DN(dn->child)->devfn);
 132                 pci_scan_slot(bus, PCI_DEVFN(slotno, 0));
 133                 max = bus->busn_res.start;
 134                 /*
 135                  * Scan bridges that are already configured. We don't touch
 136                  * them unless they are misconfigured (which will be done in
 137                  * the second scan below).
 138                  */
 139                 for_each_pci_bridge(dev, bus)
 140                         max = pci_scan_bridge(bus, dev, max, 0);
 141
 142                 /* Scan bridges that need to be reconfigured */
 143                 for_each_pci_bridge(dev, bus)
 144                         max = pci_scan_bridge(bus, dev, max, 1);
 145         }
 146         pcibios_finish_adding_to_bus(bus);
 147 }
 148 EXPORT_SYMBOL_GPL(pci_hp_add_devices);