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(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 */
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(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