text: // 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>
   *
   */
  
  #define dev_fmt(fmt) "pciehp: " fmt
  
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/pci.h>
  #include "../pci.h"
  #include "pciehp.h"
  
  /**
   * pciehp_configure_device() - enumerate PCI devices below a hotplug bridge
   * @ctrl: PCIe hotplug controller
   *
   * Enumerate PCI devices below a hotplug bridge and add them to the system.
   * Return 0 on success, %-EEXIST if the devices are already enumerated or
   * %-ENODEV if enumeration failed.
   */
  int pciehp_configure_device(struct controller *ctrl)
  {
  	struct pci_dev *dev;
  	struct pci_dev *bridge = ctrl->pcie->port;
  	struct pci_bus *parent = bridge->subordinate;
  	int num, ret = 0;
  
  	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;
  }
  
  /**
   * pciehp_unconfigure_device() - remove PCI devices below a hotplug bridge
   * @ctrl: PCIe hotplug controller
   * @presence: whether the card is still present in the slot;
   *	true for safe removal via sysfs or an Attention Button press,
   *	false for surprise removal
   *
   * Unbind PCI devices below a hotplug bridge from their drivers and remove
   * them from the system.  Safely removed devices are quiesced.  Surprise
   * removed devices are marked as such to prevent further accesses.
   */
  void pciehp_unconfigure_device(struct controller *ctrl, bool presence)
  {
  	struct pci_dev *dev, *temp;
  	struct pci_bus *parent = ctrl->pcie->port->subordinate;
  	u16 command;
  
  	ctrl_dbg(ctrl, "%s: domain:bus:dev = %04x:%02x:00\n",
  		 __func__, pci_domain_nr(parent), parent->number);
  
  	if (!presence)
  		pci_walk_bus(parent, pci_dev_set_disconnected, NULL);
  
  	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);
  		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();
  }
  