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 #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  */
  32 int 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         dev = pci_get_slot(parent, PCI_DEVFN(0, 0));
  76         ctrl->dsn = pci_get_dsn(dev);
  77         pci_dev_put(dev);
  78
  79  out:
  80         pci_unlock_rescan_remove();
  81         return ret;
  82 }
  83
  84 /**
  85  * pciehp_unconfigure_device() - remove PCI devices below a hotplug bridge
  86  * @ctrl: PCIe hotplug controller
  87  * @presence: whether the card is still present in the slot;
  88  *      true for safe removal via sysfs or an Attention Button press,
  89  *      false for surprise removal
  90  *
  91  * Unbind PCI devices below a hotplug bridge from their drivers and remove
  92  * them from the system.  Safely removed devices are quiesced.  Surprise
  93  * removed devices are marked as such to prevent further accesses.
  94  */
  95 void pciehp_unconfigure_device(struct controller *ctrl, bool presence)
  96 {
  97         struct pci_dev *dev, *temp;
  98         struct pci_bus *parent = ctrl->pcie->port->subordinate;
  99         u16 command;
 100
 101         ctrl_dbg(ctrl, "%s: domain:bus:dev = %04x:%02x:00\n",
 102                  __func__, pci_domain_nr(parent), parent->number);
 103
 104         if (!presence)
 105                 pci_walk_bus(parent, pci_dev_set_disconnected, NULL);
 106
 107         pci_lock_rescan_remove();
 108
 109         /*
 110          * Stopping an SR-IOV PF device removes all the associated VFs,
 111          * which will update the bus->devices list and confuse the
 112          * iterator.  Therefore, iterate in reverse so we remove the VFs
 113          * first, then the PF.  We do the same in pci_stop_bus_device().
 114          */
 115         list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
 116                                          bus_list) {
 117                 pci_dev_get(dev);
 118
 119                 /*
 120                  * Release reset_lock during driver unbinding
 121                  * to avoid AB-BA deadlock with device_lock.
 122                  */
 123                 up_read(&ctrl->reset_lock);
 124                 pci_stop_and_remove_bus_device(dev);
 125                 down_read_nested(&ctrl->reset_lock, ctrl->depth);
 126
 127                 /*
 128                  * Ensure that no new Requests will be generated from
 129                  * the device.
 130                  */
 131                 if (presence) {
 132                         pci_read_config_word(dev, PCI_COMMAND, &command);
 133                         command &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_SERR);
 134                         command |= PCI_COMMAND_INTX_DISABLE;
 135                         pci_write_config_word(dev, PCI_COMMAND, command);
 136                 }
 137                 pci_dev_put(dev);
 138         }
 139
 140         pci_unlock_rescan_remove();
 141 }