drivers/xen/xen-pciback/vpci.c

   1 /*
   2  * PCI Backend - Provides a Virtual PCI bus (with real devices)
   3  *               to the frontend
   4  *
   5  *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
   6  */
   7
   8 #include <linux/list.h>
   9 #include <linux/slab.h>
  10 #include <linux/pci.h>
  11 #include <linux/spinlock.h>
  12 #include "pciback.h"
  13
  14 #define PCI_SLOT_MAX 32
  15 #define DRV_NAME        "xen-pciback"
  16
  17 struct vpci_dev_data {
  18         /* Access to dev_list must be protected by lock */
  19         struct list_head dev_list[PCI_SLOT_MAX];
  20         spinlock_t lock;
  21 };
  22
  23 static inline struct list_head *list_first(struct list_head *head)
  24 {
  25         return head->next;
  26 }
  27
  28 struct pci_dev *xen_pcibk_get_pci_dev(struct xen_pcibk_device *pdev,
  29                                       unsigned int domain, unsigned int bus,
  30                                       unsigned int devfn)
  31 {
  32         struct pci_dev_entry *entry;
  33         struct pci_dev *dev = NULL;
  34         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
  35         unsigned long flags;
  36
  37         if (domain != 0 || bus != 0)
  38                 return NULL;
  39
  40         if (PCI_SLOT(devfn) < PCI_SLOT_MAX) {
  41                 spin_lock_irqsave(&vpci_dev->lock, flags);
  42
  43                 list_for_each_entry(entry,
  44                                     &vpci_dev->dev_list[PCI_SLOT(devfn)],
  45                                     list) {
  46                         if (PCI_FUNC(entry->dev->devfn) == PCI_FUNC(devfn)) {
  47                                 dev = entry->dev;
  48                                 break;
  49                         }
  50                 }
  51
  52                 spin_unlock_irqrestore(&vpci_dev->lock, flags);
  53         }
  54         return dev;
  55 }
  56
  57 static inline int match_slot(struct pci_dev *l, struct pci_dev *r)
  58 {
  59         if (pci_domain_nr(l->bus) == pci_domain_nr(r->bus)
  60             && l->bus == r->bus && PCI_SLOT(l->devfn) == PCI_SLOT(r->devfn))
  61                 return 1;
  62
  63         return 0;
  64 }
  65
  66 int xen_pcibk_add_pci_dev(struct xen_pcibk_device *pdev, struct pci_dev *dev,
  67                           int devid, publish_pci_dev_cb publish_cb)
  68 {
  69         int err = 0, slot, func = -1;
  70         struct pci_dev_entry *t, *dev_entry;
  71         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
  72         unsigned long flags;
  73
  74         if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) {
  75                 err = -EFAULT;
  76                 xenbus_dev_fatal(pdev->xdev, err,
  77                                  "Can't export bridges on the virtual PCI bus");
  78                 goto out;
  79         }
  80
  81         dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);
  82         if (!dev_entry) {
  83                 err = -ENOMEM;
  84                 xenbus_dev_fatal(pdev->xdev, err,
  85                                  "Error adding entry to virtual PCI bus");
  86                 goto out;
  87         }
  88
  89         dev_entry->dev = dev;
  90
  91         spin_lock_irqsave(&vpci_dev->lock, flags);
  92
  93         /* Keep multi-function devices together on the virtual PCI bus */
  94         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
  95                 if (!list_empty(&vpci_dev->dev_list[slot])) {
  96                         t = list_entry(list_first(&vpci_dev->dev_list[slot]),
  97                                        struct pci_dev_entry, list);
  98
  99                         if (match_slot(dev, t->dev)) {
 100                                 pr_info(DRV_NAME ": vpci: %s: "
 101                                         "assign to virtual slot %d func %d\n",
 102                                         pci_name(dev), slot,
 103                                         PCI_FUNC(dev->devfn));
 104                                 list_add_tail(&dev_entry->list,
 105                                               &vpci_dev->dev_list[slot]);
 106                                 func = PCI_FUNC(dev->devfn);
 107                                 goto unlock;
 108                         }
 109                 }
 110         }
 111
 112         /* Assign to a new slot on the virtual PCI bus */
 113         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 114                 if (list_empty(&vpci_dev->dev_list[slot])) {
 115                         printk(KERN_INFO DRV_NAME
 116                                ": vpci: %s: assign to virtual slot %d\n",
 117                                pci_name(dev), slot);
 118                         list_add_tail(&dev_entry->list,
 119                                       &vpci_dev->dev_list[slot]);
 120                         func = PCI_FUNC(dev->devfn);
 121                         goto unlock;
 122                 }
 123         }
 124
 125         err = -ENOMEM;
 126         xenbus_dev_fatal(pdev->xdev, err,
 127                          "No more space on root virtual PCI bus");
 128
 129 unlock:
 130         spin_unlock_irqrestore(&vpci_dev->lock, flags);
 131
 132         /* Publish this device. */
 133         if (!err)
 134                 err = publish_cb(pdev, 0, 0, PCI_DEVFN(slot, func), devid);
 135
 136 out:
 137         return err;
 138 }
 139
 140 void xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
 141                                struct pci_dev *dev)
 142 {
 143         int slot;
 144         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 145         struct pci_dev *found_dev = NULL;
 146         unsigned long flags;
 147
 148         spin_lock_irqsave(&vpci_dev->lock, flags);
 149
 150         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 151                 struct pci_dev_entry *e, *tmp;
 152                 list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
 153                                          list) {
 154                         if (e->dev == dev) {
 155                                 list_del(&e->list);
 156                                 found_dev = e->dev;
 157                                 kfree(e);
 158                                 goto out;
 159                         }
 160                 }
 161         }
 162
 163 out:
 164         spin_unlock_irqrestore(&vpci_dev->lock, flags);
 165
 166         if (found_dev)
 167                 pcistub_put_pci_dev(found_dev);
 168 }
 169
 170 int xen_pcibk_init_devices(struct xen_pcibk_device *pdev)
 171 {
 172         int slot;
 173         struct vpci_dev_data *vpci_dev;
 174
 175         vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL);
 176         if (!vpci_dev)
 177                 return -ENOMEM;
 178
 179         spin_lock_init(&vpci_dev->lock);
 180
 181         for (slot = 0; slot < PCI_SLOT_MAX; slot++)
 182                 INIT_LIST_HEAD(&vpci_dev->dev_list[slot]);
 183
 184         pdev->pci_dev_data = vpci_dev;
 185
 186         return 0;
 187 }
 188
 189 int xen_pcibk_publish_pci_roots(struct xen_pcibk_device *pdev,
 190                                 publish_pci_root_cb publish_cb)
 191 {
 192         /* The Virtual PCI bus has only one root */
 193         return publish_cb(pdev, 0, 0);
 194 }
 195
 196 void xen_pcibk_release_devices(struct xen_pcibk_device *pdev)
 197 {
 198         int slot;
 199         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 200
 201         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 202                 struct pci_dev_entry *e, *tmp;
 203                 list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
 204                                          list) {
 205                         list_del(&e->list);
 206                         pcistub_put_pci_dev(e->dev);
 207                         kfree(e);
 208                 }
 209         }
 210
 211         kfree(vpci_dev);
 212         pdev->pci_dev_data = NULL;
 213 }
 214
 215 int xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
 216                                struct xen_pcibk_device *pdev,
 217                                unsigned int *domain, unsigned int *bus,
 218                                unsigned int *devfn)
 219 {
 220         struct pci_dev_entry *entry;
 221         struct pci_dev *dev = NULL;
 222         struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
 223         unsigned long flags;
 224         int found = 0, slot;
 225
 226         spin_lock_irqsave(&vpci_dev->lock, flags);
 227         for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
 228                 list_for_each_entry(entry,
 229                             &vpci_dev->dev_list[slot],
 230                             list) {
 231                         dev = entry->dev;
 232                         if (dev && dev->bus->number == pcidev->bus->number
 233                                 && pci_domain_nr(dev->bus) ==
 234                                         pci_domain_nr(pcidev->bus)
 235                                 && dev->devfn == pcidev->devfn) {
 236                                 found = 1;
 237                                 *domain = 0;
 238                                 *bus = 0;
 239                                 *devfn = PCI_DEVFN(slot,
 240                                          PCI_FUNC(pcidev->devfn));
 241                         }
 242                 }
 243         }
 244         spin_unlock_irqrestore(&vpci_dev->lock, flags);
 245         return found;
 246 }