1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * PCI Express Hot Plug Controller Driver 4 * 5 * Copyright (C) 1995,2001 Compaq Computer Corporation 6 * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com) 7 * Copyright (C) 2001 IBM Corp. 8 * Copyright (C) 2003-2004 Intel Corporation 9 * 10 * All rights reserved. 11 * 12 * Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com> 13 * 14 */ 15 16 #define dev_fmt(fmt) "pciehp: " fmt 17 18 #include <linux/kernel.h> 19 #include <linux/types.h> 20 #include <linux/pci.h> 21 #include "../pci.h" 22 #include "pciehp.h" 23 24 /** 25 * pciehp_configure_device() - enumerate PCI devices below a hotplug bridge 26 * @ctrl: PCIe hotplug controller 27 * 28 * Enumerate PCI devices below a hotplug bridge and add them to the system. 29 * Return 0 on success, %-EEXIST if the devices are already enumerated or 30 * %-ENODEV if enumeration failed. 31 */ 32 int pciehp_configure_device(struct controller *ctrl) 33 { 34 struct pci_dev *dev; 35 struct pci_dev *bridge = ctrl->pcie->port; 36 struct pci_bus *parent = bridge->subordinate; 37 int num, ret = 0; 38 39 pci_lock_rescan_remove(); 40 41 dev = pci_get_slot(parent, PCI_DEVFN(0, 0)); 42 if (dev) { 43 /* 44 * The device is already there. Either configured by the 45 * boot firmware or a previous hotplug event. 46 */ 47 ctrl_dbg(ctrl, "Device %s already exists at %04x:%02x:00, skipping hot-add\n", 48 pci_name(dev), pci_domain_nr(parent), parent->number); 49 pci_dev_put(dev); 50 ret = -EEXIST; 51 goto out; 52 } 53 54 num = pci_scan_slot(parent, PCI_DEVFN(0, 0)); 55 if (num == 0) { 56 ctrl_err(ctrl, "No new device found\n"); 57 ret = -ENODEV; 58 goto out; 59 } 60 61 for_each_pci_bridge(dev, parent) 62 pci_hp_add_bridge(dev); 63 64 pci_assign_unassigned_bridge_resources(bridge); 65 pcie_bus_configure_settings(parent); 66 67 /* 68 * Release reset_lock during driver binding 69 * to avoid AB-BA deadlock with device_lock. 70 */ 71 up_read(&ctrl->reset_lock); 72 pci_bus_add_devices(parent); 73 down_read_nested(&ctrl->reset_lock, ctrl->depth); 74 75 out: 76 pci_unlock_rescan_remove(); 77 return ret; 78 } 79 80 /** 81 * pciehp_unconfigure_device() - remove PCI devices below a hotplug bridge 82 * @ctrl: PCIe hotplug controller 83 * @presence: whether the card is still present in the slot; 84 * true for safe removal via sysfs or an Attention Button press, 85 * false for surprise removal 86 * 87 * Unbind PCI devices below a hotplug bridge from their drivers and remove 88 * them from the system. Safely removed devices are quiesced. Surprise 89 * removed devices are marked as such to prevent further accesses. 90 */ 91 void pciehp_unconfigure_device(struct controller *ctrl, bool presence) 92 { 93 struct pci_dev *dev, *temp; 94 struct pci_bus *parent = ctrl->pcie->port->subordinate; 95 u16 command; 96 97 ctrl_dbg(ctrl, "%s: domain:bus:dev = %04x:%02x:00\n", 98 __func__, pci_domain_nr(parent), parent->number); 99 100 if (!presence) 101 pci_walk_bus(parent, pci_dev_set_disconnected, NULL); 102 103 pci_lock_rescan_remove(); 104 105 /* 106 * Stopping an SR-IOV PF device removes all the associated VFs, 107 * which will update the bus->devices list and confuse the 108 * iterator. Therefore, iterate in reverse so we remove the VFs 109 * first, then the PF. We do the same in pci_stop_bus_device(). 110 */ 111 list_for_each_entry_safe_reverse(dev, temp, &parent->devices, 112 bus_list) { 113 pci_dev_get(dev); 114 115 /* 116 * Release reset_lock during driver unbinding 117 * to avoid AB-BA deadlock with device_lock. 118 */ 119 up_read(&ctrl->reset_lock); 120 pci_stop_and_remove_bus_device(dev); 121 down_read_nested(&ctrl->reset_lock, ctrl->depth); 122 123 /* 124 * Ensure that no new Requests will be generated from 125 * the device. 126 */ 127 if (presence) { 128 pci_read_config_word(dev, PCI_COMMAND, &command); 129 command &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_SERR); 130 command |= PCI_COMMAND_INTX_DISABLE; 131 pci_write_config_word(dev, PCI_COMMAND, command); 132 } 133 pci_dev_put(dev); 134 } 135 136 pci_unlock_rescan_remove(); 137 } 138