drivers/pci/hotplug/fakephp.c

   1 /* Works like the fakephp driver used to, except a little better.
   2  *
   3  * - It's possible to remove devices with subordinate busses.
   4  * - New PCI devices that appear via any method, not just a fakephp triggered
   5  *   rescan, will be noticed.
   6  * - Devices that are removed via any method, not just a fakephp triggered
   7  *   removal, will also be noticed.
   8  *
   9  * Uses nothing from the pci-hotplug subsystem.
  10  *
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/types.h>
  16 #include <linux/list.h>
  17 #include <linux/kobject.h>
  18 #include <linux/sysfs.h>
  19 #include <linux/init.h>
  20 #include <linux/pci.h>
  21 #include <linux/device.h>
  22 #include "../pci.h"
  23
  24 struct legacy_slot {
  25         struct kobject          kobj;
  26         struct pci_dev          *dev;
  27         struct list_head        list;
  28 };
  29
  30 static LIST_HEAD(legacy_list);
  31
  32 static ssize_t legacy_show(struct kobject *kobj, struct attribute *attr,
  33                            char *buf)
  34 {
  35         struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
  36         strcpy(buf, "1\n");
  37         return 2;
  38 }
  39
  40 static void remove_callback(void *data)
  41 {
  42         pci_remove_bus_device((struct pci_dev *)data);
  43 }
  44
  45 static ssize_t legacy_store(struct kobject *kobj, struct attribute *attr,
  46                             const char *buf, size_t len)
  47 {
  48         struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
  49         unsigned long val;
  50
  51         if (strict_strtoul(buf, 0, &val) < 0)
  52                 return -EINVAL;
  53
  54         if (val)
  55                 pci_rescan_bus(slot->dev->bus);
  56         else
  57                 sysfs_schedule_callback(&slot->dev->dev.kobj, remove_callback,
  58                                         slot->dev, THIS_MODULE);
  59         return len;
  60 }
  61
  62 static struct attribute *legacy_attrs[] = {
  63         &(struct attribute){ .name = "power", .mode = 0644 },
  64         NULL,
  65 };
  66
  67 static void legacy_release(struct kobject *kobj)
  68 {
  69         struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
  70
  71         pci_dev_put(slot->dev);
  72         kfree(slot);
  73 }
  74
  75 static struct kobj_type legacy_ktype = {
  76         .sysfs_ops = &(struct sysfs_ops){
  77                 .store = legacy_store, .show = legacy_show
  78         },
  79         .release = &legacy_release,
  80         .default_attrs = legacy_attrs,
  81 };
  82
  83 static int legacy_add_slot(struct pci_dev *pdev)
  84 {
  85         struct legacy_slot *slot = kzalloc(sizeof(*slot), GFP_KERNEL);
  86
  87         if (!slot)
  88                 return -ENOMEM;
  89
  90         if (kobject_init_and_add(&slot->kobj, &legacy_ktype,
  91                                  &pci_slots_kset->kobj, "%s",
  92                                  dev_name(&pdev->dev))) {
  93                 dev_warn(&pdev->dev, "Failed to created legacy fake slot\n");
  94                 return -EINVAL;
  95         }
  96         slot->dev = pci_dev_get(pdev);
  97
  98         list_add(&slot->list, &legacy_list);
  99
 100         return 0;
 101 }
 102
 103 static int legacy_notify(struct notifier_block *nb,
 104                          unsigned long action, void *data)
 105 {
 106         struct pci_dev *pdev = to_pci_dev(data);
 107
 108         if (action == BUS_NOTIFY_ADD_DEVICE) {
 109                 legacy_add_slot(pdev);
 110         } else if (action == BUS_NOTIFY_DEL_DEVICE) {
 111                 struct legacy_slot *slot;
 112
 113                 list_for_each_entry(slot, &legacy_list, list)
 114                         if (slot->dev == pdev)
 115                                 goto found;
 116
 117                 dev_warn(&pdev->dev, "Missing legacy fake slot?");
 118                 return -ENODEV;
 119 found:
 120                 kobject_del(&slot->kobj);
 121                 list_del(&slot->list);
 122                 kobject_put(&slot->kobj);
 123         }
 124
 125         return 0;
 126 }
 127
 128 static struct notifier_block legacy_notifier = {
 129         .notifier_call = legacy_notify
 130 };
 131
 132 static int __init init_legacy(void)
 133 {
 134         struct pci_dev *pdev = NULL;
 135
 136         /* Add existing devices */
 137         while ((pdev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pdev)))
 138                 legacy_add_slot(pdev);
 139
 140         /* Be alerted of any new ones */
 141         bus_register_notifier(&pci_bus_type, &legacy_notifier);
 142         return 0;
 143 }
 144 module_init(init_legacy);
 145
 146 static void __exit remove_legacy(void)
 147 {
 148         struct legacy_slot *slot, *tmp;
 149
 150         bus_unregister_notifier(&pci_bus_type, &legacy_notifier);
 151
 152         list_for_each_entry_safe(slot, tmp, &legacy_list, list) {
 153                 list_del(&slot->list);
 154                 kobject_del(&slot->kobj);
 155                 kobject_put(&slot->kobj);
 156         }
 157 }
 158 module_exit(remove_legacy);
 159
 160
 161 MODULE_AUTHOR("Trent Piepho <xyzzy@speakeasy.org>");
 162 MODULE_DESCRIPTION("Legacy version of the fakephp interface");
 163 MODULE_LICENSE("GPL");