drivers/pci/hotplug/pciehp_pci.c

   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 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/types.h>
  19 #include <linux/pci.h>
  20 #include "../pci.h"
  21 #include "pciehp.h"
  22
  23 int pciehp_configure_device(struct slot *p_slot)
  24 {
  25         struct pci_dev *dev;
  26         struct pci_dev *bridge = p_slot->ctrl->pcie->port;
  27         struct pci_bus *parent = bridge->subordinate;
  28         int num, ret = 0;
  29         struct controller *ctrl = p_slot->ctrl;
  30
  31         pci_lock_rescan_remove();
  32
  33         dev = pci_get_slot(parent, PCI_DEVFN(0, 0));
  34         if (dev) {
  35                 /*
  36                  * The device is already there. Either configured by the
  37                  * boot firmware or a previous hotplug event.
  38                  */
  39                 ctrl_dbg(ctrl, "Device %s already exists at %04x:%02x:00, skipping hot-add\n",
  40                          pci_name(dev), pci_domain_nr(parent), parent->number);
  41                 pci_dev_put(dev);
  42                 ret = -EEXIST;
  43                 goto out;
  44         }
  45
  46         num = pci_scan_slot(parent, PCI_DEVFN(0, 0));
  47         if (num == 0) {
  48                 ctrl_err(ctrl, "No new device found\n");
  49                 ret = -ENODEV;
  50                 goto out;
  51         }
  52
  53         for_each_pci_bridge(dev, parent)
  54                 pci_hp_add_bridge(dev);
  55
  56         pci_assign_unassigned_bridge_resources(bridge);
  57         pcie_bus_configure_settings(parent);
  58
  59         /*
  60          * Release reset_lock during driver binding
  61          * to avoid AB-BA deadlock with device_lock.
  62          */
  63         up_read(&ctrl->reset_lock);
  64         pci_bus_add_devices(parent);
  65         down_read_nested(&ctrl->reset_lock, ctrl->depth);
  66
  67  out:
  68         pci_unlock_rescan_remove();
  69         return ret;
  70 }
  71
  72 void pciehp_unconfigure_device(struct slot *p_slot)
  73 {
  74         u8 presence = 0;
  75         struct pci_dev *dev, *temp;
  76         struct pci_bus *parent = p_slot->ctrl->pcie->port->subordinate;
  77         u16 command;
  78         struct controller *ctrl = p_slot->ctrl;
  79
  80         ctrl_dbg(ctrl, "%s: domain:bus:dev = %04x:%02x:00\n",
  81                  __func__, pci_domain_nr(parent), parent->number);
  82         pciehp_get_adapter_status(p_slot, &presence);
  83
  84         pci_lock_rescan_remove();
  85
  86         /*
  87          * Stopping an SR-IOV PF device removes all the associated VFs,
  88          * which will update the bus->devices list and confuse the
  89          * iterator.  Therefore, iterate in reverse so we remove the VFs
  90          * first, then the PF.  We do the same in pci_stop_bus_device().
  91          */
  92         list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
  93                                          bus_list) {
  94                 pci_dev_get(dev);
  95                 if (!presence) {
  96                         pci_dev_set_disconnected(dev, NULL);
  97                         if (pci_has_subordinate(dev))
  98                                 pci_walk_bus(dev->subordinate,
  99                                              pci_dev_set_disconnected, NULL);
 100                 }
 101
 102                 /*
 103                  * Release reset_lock during driver unbinding
 104                  * to avoid AB-BA deadlock with device_lock.
 105                  */
 106                 up_read(&ctrl->reset_lock);
 107                 pci_stop_and_remove_bus_device(dev);
 108                 down_read_nested(&ctrl->reset_lock, ctrl->depth);
 109
 110                 /*
 111                  * Ensure that no new Requests will be generated from
 112                  * the device.
 113                  */
 114                 if (presence) {
 115                         pci_read_config_word(dev, PCI_COMMAND, &command);
 116                         command &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_SERR);
 117                         command |= PCI_COMMAND_INTX_DISABLE;
 118                         pci_write_config_word(dev, PCI_COMMAND, command);
 119                 }
 120                 pci_dev_put(dev);
 121         }
 122
 123         pci_unlock_rescan_remove();
 124 }