linux_kernel/drivers/pci/hotplug/pciehp_pci.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * PCI Express Hot Plug Controller Driver
 *
 * Copyright (C) 1995,2001 Compaq Computer Corporation
 * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
 * Copyright (C) 2001 IBM Corp.
 * Copyright (C) 2003-2004 Intel Corporation
 *
 * All rights reserved.
 *
 * Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/pci.h>
#include "../pci.h"
#include "pciehp.h"

int pciehp_configure_device(struct slot *p_slot)
{
	struct pci_dev *dev;
	struct pci_dev *bridge = p_slot->ctrl->pcie->port;
	struct pci_bus *parent = bridge->subordinate;
	int num, ret = 0;
	struct controller *ctrl = p_slot->ctrl;

	pci_lock_rescan_remove();

	dev = pci_get_slot(parent, PCI_DEVFN(0, 0));
	if (dev) {
		/*
		 * The device is already there. Either configured by the
		 * boot firmware or a previous hotplug event.
		 */
		ctrl_dbg(ctrl, "Device %s already exists at %04x:%02x:00, skipping hot-add\n",
			 pci_name(dev), pci_domain_nr(parent), parent->number);
		pci_dev_put(dev);
		ret = -EEXIST;
		goto out;
	}

	num = pci_scan_slot(parent, PCI_DEVFN(0, 0));
	if (num == 0) {
		ctrl_err(ctrl, "No new device found\n");
		ret = -ENODEV;
		goto out;
	}

	for_each_pci_bridge(dev, parent)
		pci_hp_add_bridge(dev);

	pci_assign_unassigned_bridge_resources(bridge);
	pcie_bus_configure_settings(parent);
	pci_bus_add_devices(parent);

 out:
	pci_unlock_rescan_remove();
	return ret;
}

int pciehp_unconfigure_device(struct slot *p_slot)
{
	int rc = 0;
	u8 bctl = 0;
	u8 presence = 0;
	struct pci_dev *dev, *temp;
	struct pci_bus *parent = p_slot->ctrl->pcie->port->subordinate;
	u16 command;
	struct controller *ctrl = p_slot->ctrl;

	ctrl_dbg(ctrl, "%s: domain:bus:dev = %04x:%02x:00\n",
		 __func__, pci_domain_nr(parent), parent->number);
	pciehp_get_adapter_status(p_slot, &presence);

	pci_lock_rescan_remove();

	/*
	 * Stopping an SR-IOV PF device removes all the associated VFs,
	 * which will update the bus->devices list and confuse the
	 * iterator.  Therefore, iterate in reverse so we remove the VFs
	 * first, then the PF.  We do the same in pci_stop_bus_device().
	 */
	list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
					 bus_list) {
		pci_dev_get(dev);
		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE && presence) {
			pci_read_config_byte(dev, PCI_BRIDGE_CONTROL, &bctl);
			if (bctl & PCI_BRIDGE_CTL_VGA) {
				ctrl_err(ctrl,
					 "Cannot remove display device %s\n",
					 pci_name(dev));
				pci_dev_put(dev);
				rc = -EINVAL;
				break;
			}
		}
		if (!presence) {
			pci_dev_set_disconnected(dev, NULL);
			if (pci_has_subordinate(dev))
				pci_walk_bus(dev->subordinate,
					     pci_dev_set_disconnected, NULL);
		}
		pci_stop_and_remove_bus_device(dev);
		/*
		 * Ensure that no new Requests will be generated from
		 * the device.
		 */
		if (presence) {
			pci_read_config_word(dev, PCI_COMMAND, &command);
			command &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_SERR);
			command |= PCI_COMMAND_INTX_DISABLE;
			pci_write_config_word(dev, PCI_COMMAND, command);
		}
		pci_dev_put(dev);
	}

	pci_unlock_rescan_remove();
	return rc;
}