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 */
32int 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(bus: 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(bus: 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(bus: parent);
66
67 /*
68 * Release reset_lock during driver binding
69 * to avoid AB-BA deadlock with device_lock.
70 */
71 up_read(sem: &ctrl->reset_lock);
72 pci_bus_add_devices(bus: parent);
73 down_read_nested(sem: &ctrl->reset_lock, subclass: 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 */
91void 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(top: parent, cb: 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(sem: &ctrl->reset_lock);
120 pci_stop_and_remove_bus_device(dev);
121 down_read_nested(sem: &ctrl->reset_lock, subclass: 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, val: &command);
129 command &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_SERR);
130 command |= PCI_COMMAND_INTX_DISABLE;
131 pci_write_config_word(dev, PCI_COMMAND, val: command);
132 }
133 pci_dev_put(dev);
134 }
135
136 pci_unlock_rescan_remove();
137}
138

source code of linux/drivers/pci/hotplug/pciehp_pci.c