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 <linux/slab.h>
  23 #include "../pci.h"
  24
  25 struct legacy_slot {
  26         struct kobject          kobj;
  27         struct pci_dev          *dev;
  28         struct list_head        list;
  29 };
  30
  31 static LIST_HEAD(legacy_list);
  32
  33 static ssize_t legacy_show(struct kobject *kobj, struct attribute *attr,
  34                            char *buf)
  35 {
  36         struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
  37         strcpy(buf, "1\n");
  38         return 2;
  39 }
  40
  41 static void remove_callback(void *data)
  42 {
  43         pci_remove_bus_device((struct pci_dev *)data);
  44 }
  45
  46 static ssize_t legacy_store(struct kobject *kobj, struct attribute *attr,
  47                             const char *buf, size_t len)
  48 {
  49         struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
  50         unsigned long val;
  51
  52         if (strict_strtoul(buf, 0, &val) < 0)
  53                 return -EINVAL;
  54
  55         if (val)
  56                 pci_rescan_bus(slot->dev->bus);
  57         else
  58                 sysfs_schedule_callback(&slot->dev->dev.kobj, remove_callback,
  59                                         slot->dev, THIS_MODULE);
  60         return len;
  61 }
  62
  63 static struct attribute *legacy_attrs[] = {
  64         &(struct attribute){ .name = "power", .mode = 0644 },
  65         NULL,
  66 };
  67
  68 static void legacy_release(struct kobject *kobj)
  69 {
  70         struct legacy_slot *slot = container_of(kobj, typeof(*slot), kobj);
  71
  72         pci_dev_put(slot->dev);
  73         kfree(slot);
  74 }
  75
  76 static struct kobj_type legacy_ktype = {
  77         .sysfs_ops = &(const struct sysfs_ops){
  78                 .store = legacy_store, .show = legacy_show
  79         },
  80         .release = &legacy_release,
  81         .default_attrs = legacy_attrs,
  82 };
  83
  84 static int legacy_add_slot(struct pci_dev *pdev)
  85 {
  86         struct legacy_slot *slot = kzalloc(sizeof(*slot), GFP_KERNEL);
  87
  88         if (!slot)
  89                 return -ENOMEM;
  90
  91         if (kobject_init_and_add(&slot->kobj, &legacy_ktype,
  92                                  &pci_slots_kset->kobj, "%s",
  93                                  dev_name(&pdev->dev))) {
  94                 dev_warn(&pdev->dev, "Failed to created legacy fake slot\n");
  95                 return -EINVAL;
  96         }
  97         slot->dev = pci_dev_get(pdev);
  98
  99         list_add(&slot->list, &legacy_list);
 100
 101         return 0;
 102 }
 103
 104 static int legacy_notify(struct notifier_block *nb,
 105                          unsigned long action, void *data)
 106 {
 107         struct pci_dev *pdev = to_pci_dev(data);
 108
 109         if (action == BUS_NOTIFY_ADD_DEVICE) {
 110                 legacy_add_slot(pdev);
 111         } else if (action == BUS_NOTIFY_DEL_DEVICE) {
 112                 struct legacy_slot *slot;
 113
 114                 list_for_each_entry(slot, &legacy_list, list)
 115                         if (slot->dev == pdev)
 116                                 goto found;
 117
 118                 dev_warn(&pdev->dev, "Missing legacy fake slot?");
 119                 return -ENODEV;
 120 found:
 121                 kobject_del(&slot->kobj);
 122                 list_del(&slot->list);
 123                 kobject_put(&slot->kobj);
 124         }
 125
 126         return 0;
 127 }
 128
 129 static struct notifier_block legacy_notifier = {
 130         .notifier_call = legacy_notify
 131 };
 132
 133 static int __init init_legacy(void)
 134 {
 135         struct pci_dev *pdev = NULL;
 136
 137         /* Add existing devices */
 138         for_each_pci_dev(pdev)
 139                 legacy_add_slot(pdev);
 140
 141         /* Be alerted of any new ones */
 142         bus_register_notifier(&pci_bus_type, &legacy_notifier);
 143         return 0;
 144 }
 145 module_init(init_legacy);
 146
 147 static void __exit remove_legacy(void)
 148 {
 149         struct legacy_slot *slot, *tmp;
 150
 151         bus_unregister_notifier(&pci_bus_type, &legacy_notifier);
 152
 153         list_for_each_entry_safe(slot, tmp, &legacy_list, list) {
 154                 list_del(&slot->list);
 155                 kobject_del(&slot->kobj);
 156                 kobject_put(&slot->kobj);
 157         }
 158 }
 159 module_exit(remove_legacy);
 160
 161
 162 MODULE_AUTHOR("Trent Piepho <xyzzy@speakeasy.org>");
 163 MODULE_DESCRIPTION("Legacy version of the fakephp interface");
 164 MODULE_LICENSE("GPL");