powerpc/kernel/pci-hotplug.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Derived from "arch/powerpc/platforms/pseries/pci_dlpar.c"
0004  *
0005  * Copyright (C) 2003 Linda Xie <lxie@us.ibm.com>
0006  * Copyright (C) 2005 International Business Machines
0007  *
0008  * Updates, 2005, John Rose <johnrose@austin.ibm.com>
0009  * Updates, 2005, Linas Vepstas <linas@austin.ibm.com>
0010  * Updates, 2013, Gavin Shan <shangw@linux.vnet.ibm.com>
0011  */
0012
0013 #include <linux/pci.h>
0014 #include <linux/export.h>
0015 #include <linux/of.h>
0016 #include <asm/pci-bridge.h>
0017 #include <asm/ppc-pci.h>
0018 #include <asm/firmware.h>
0019 #include <asm/eeh.h>
0020
0021 static struct pci_bus *find_bus_among_children(struct pci_bus *bus,
0022                            struct device_node *dn)
0023 {
0024     struct pci_bus *child = NULL;
0025     struct pci_bus *tmp;
0026
0027     if (pci_bus_to_OF_node(bus) == dn)
0028         return bus;
0029
0030     list_for_each_entry(tmp, &bus->children, node) {
0031         child = find_bus_among_children(tmp, dn);
0032         if (child)
0033             break;
0034     }
0035
0036     return child;
0037 }
0038
0039 struct pci_bus *pci_find_bus_by_node(struct device_node *dn)
0040 {
0041     struct pci_dn *pdn = PCI_DN(dn);
0042
0043     if (!pdn  || !pdn->phb || !pdn->phb->bus)
0044         return NULL;
0045
0046     return find_bus_among_children(pdn->phb->bus, dn);
0047 }
0048 EXPORT_SYMBOL_GPL(pci_find_bus_by_node);
0049
0050 /**
0051  * pcibios_release_device - release PCI device
0052  * @dev: PCI device
0053  *
0054  * The function is called before releasing the indicated PCI device.
0055  */
0056 void pcibios_release_device(struct pci_dev *dev)
0057 {
0058     struct pci_controller *phb = pci_bus_to_host(dev->bus);
0059     struct pci_dn *pdn = pci_get_pdn(dev);
0060
0061     if (phb->controller_ops.release_device)
0062         phb->controller_ops.release_device(dev);
0063
0064     /* free()ing the pci_dn has been deferred to us, do it now */
0065     if (pdn && (pdn->flags & PCI_DN_FLAG_DEAD)) {
0066         pci_dbg(dev, "freeing dead pdn\n");
0067         kfree(pdn);
0068     }
0069 }
0070
0071 /**
0072  * pci_hp_remove_devices - remove all devices under this bus
0073  * @bus: the indicated PCI bus
0074  *
0075  * Remove all of the PCI devices under this bus both from the
0076  * linux pci device tree, and from the powerpc EEH address cache.
0077  */
0078 void pci_hp_remove_devices(struct pci_bus *bus)
0079 {
0080     struct pci_dev *dev, *tmp;
0081     struct pci_bus *child_bus;
0082
0083     /* First go down child busses */
0084     list_for_each_entry(child_bus, &bus->children, node)
0085         pci_hp_remove_devices(child_bus);
0086
0087     pr_debug("PCI: Removing devices on bus %04x:%02x\n",
0088          pci_domain_nr(bus),  bus->number);
0089     list_for_each_entry_safe_reverse(dev, tmp, &bus->devices, bus_list) {
0090         pr_debug("   Removing %s...\n", pci_name(dev));
0091         pci_stop_and_remove_bus_device(dev);
0092     }
0093 }
0094 EXPORT_SYMBOL_GPL(pci_hp_remove_devices);
0095
0096 /**
0097  * pci_hp_add_devices - adds new pci devices to bus
0098  * @bus: the indicated PCI bus
0099  *
0100  * This routine will find and fixup new pci devices under
0101  * the indicated bus. This routine presumes that there
0102  * might already be some devices under this bridge, so
0103  * it carefully tries to add only new devices.  (And that
0104  * is how this routine differs from other, similar pcibios
0105  * routines.)
0106  */
0107 void pci_hp_add_devices(struct pci_bus *bus)
0108 {
0109     int slotno, mode, max;
0110     struct pci_dev *dev;
0111     struct pci_controller *phb;
0112     struct device_node *dn = pci_bus_to_OF_node(bus);
0113
0114     phb = pci_bus_to_host(bus);
0115
0116     mode = PCI_PROBE_NORMAL;
0117     if (phb->controller_ops.probe_mode)
0118         mode = phb->controller_ops.probe_mode(bus);
0119
0120     if (mode == PCI_PROBE_DEVTREE) {
0121         /* use ofdt-based probe */
0122         of_rescan_bus(dn, bus);
0123     } else if (mode == PCI_PROBE_NORMAL &&
0124            dn->child && PCI_DN(dn->child)) {
0125         /*
0126          * Use legacy probe. In the partial hotplug case, we
0127          * probably have grandchildren devices unplugged. So
0128          * we don't check the return value from pci_scan_slot() in
0129          * order for fully rescan all the way down to pick them up.
0130          * They can have been removed during partial hotplug.
0131          */
0132         slotno = PCI_SLOT(PCI_DN(dn->child)->devfn);
0133         pci_scan_slot(bus, PCI_DEVFN(slotno, 0));
0134         max = bus->busn_res.start;
0135         /*
0136          * Scan bridges that are already configured. We don't touch
0137          * them unless they are misconfigured (which will be done in
0138          * the second scan below).
0139          */
0140         for_each_pci_bridge(dev, bus)
0141             max = pci_scan_bridge(bus, dev, max, 0);
0142
0143         /* Scan bridges that need to be reconfigured */
0144         for_each_pci_bridge(dev, bus)
0145             max = pci_scan_bridge(bus, dev, max, 1);
0146     }
0147     pcibios_finish_adding_to_bus(bus);
0148 }
0149 EXPORT_SYMBOL_GPL(pci_hp_add_devices);