source: trunk/packages/xen-3.1/xen-3.1/linux-2.6-xen-sparse/drivers/xen/pciback/vpci.c @ 34

/*
 * PCI Backend - Provides a Virtual PCI bus (with real devices)
 *               to the frontend
 *
 *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
 */

#include <linux/list.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/spinlock.h>
#include "pciback.h"

#define PCI_SLOT_MAX 32

struct vpci_dev_data {
        /* Access to dev_list must be protected by lock */
        struct list_head dev_list[PCI_SLOT_MAX];
        spinlock_t lock;
};

static inline struct list_head *list_first(struct list_head *head)
{
        return head->next;
}

struct pci_dev *pciback_get_pci_dev(struct pciback_device *pdev,
                                    unsigned int domain, unsigned int bus,
                                    unsigned int devfn)
{
        struct pci_dev_entry *entry;
        struct pci_dev *dev = NULL;
        struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
        unsigned long flags;

        if (domain != 0 || bus != 0)
                return NULL;

        if (PCI_SLOT(devfn) < PCI_SLOT_MAX) {
                spin_lock_irqsave(&vpci_dev->lock, flags);

                list_for_each_entry(entry,
                                    &vpci_dev->dev_list[PCI_SLOT(devfn)],
                                    list) {
                        if (PCI_FUNC(entry->dev->devfn) == PCI_FUNC(devfn)) {
                                dev = entry->dev;
                                break;
                        }
                }

                spin_unlock_irqrestore(&vpci_dev->lock, flags);
        }
        return dev;
}

static inline int match_slot(struct pci_dev *l, struct pci_dev *r)
{
        if (pci_domain_nr(l->bus) == pci_domain_nr(r->bus)
            && l->bus == r->bus && PCI_SLOT(l->devfn) == PCI_SLOT(r->devfn))
                return 1;

        return 0;
}

int pciback_add_pci_dev(struct pciback_device *pdev, struct pci_dev *dev)
{
        int err = 0, slot;
        struct pci_dev_entry *t, *dev_entry;
        struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
        unsigned long flags;

        if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) {
                err = -EFAULT;
                xenbus_dev_fatal(pdev->xdev, err,
                                 "Can't export bridges on the virtual PCI bus");
                goto out;
        }

        dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL);
        if (!dev_entry) {
                err = -ENOMEM;
                xenbus_dev_fatal(pdev->xdev, err,
                                 "Error adding entry to virtual PCI bus");
                goto out;
        }

        dev_entry->dev = dev;

        spin_lock_irqsave(&vpci_dev->lock, flags);

        /* Keep multi-function devices together on the virtual PCI bus */
        for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
                if (!list_empty(&vpci_dev->dev_list[slot])) {
                        t = list_entry(list_first(&vpci_dev->dev_list[slot]),
                                       struct pci_dev_entry, list);

                        if (match_slot(dev, t->dev)) {
                                pr_info("pciback: vpci: %s: "
                                        "assign to virtual slot %d func %d\n",
                                        pci_name(dev), slot,
                                        PCI_FUNC(dev->devfn));
                                list_add_tail(&dev_entry->list,
                                              &vpci_dev->dev_list[slot]);
                                goto unlock;
                        }
                }
        }

        /* Assign to a new slot on the virtual PCI bus */
        for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
                if (list_empty(&vpci_dev->dev_list[slot])) {
                        printk(KERN_INFO
                               "pciback: vpci: %s: assign to virtual slot %d\n",
                               pci_name(dev), slot);
                        list_add_tail(&dev_entry->list,
                                      &vpci_dev->dev_list[slot]);
                        goto unlock;
                }
        }

        err = -ENOMEM;
        xenbus_dev_fatal(pdev->xdev, err,
                         "No more space on root virtual PCI bus");

      unlock:
        spin_unlock_irqrestore(&vpci_dev->lock, flags);
      out:
        return err;
}

void pciback_release_pci_dev(struct pciback_device *pdev, struct pci_dev *dev)
{
        int slot;
        struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
        struct pci_dev *found_dev = NULL;
        unsigned long flags;

        spin_lock_irqsave(&vpci_dev->lock, flags);

        for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
                struct pci_dev_entry *e, *tmp;
                list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
                                         list) {
                        if (e->dev == dev) {
                                list_del(&e->list);
                                found_dev = e->dev;
                                kfree(e);
                                goto out;
                        }
                }
        }

      out:
        spin_unlock_irqrestore(&vpci_dev->lock, flags);

        if (found_dev)
                pcistub_put_pci_dev(found_dev);
}

int pciback_init_devices(struct pciback_device *pdev)
{
        int slot;
        struct vpci_dev_data *vpci_dev;

        vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL);
        if (!vpci_dev)
                return -ENOMEM;

        spin_lock_init(&vpci_dev->lock);

        for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
                INIT_LIST_HEAD(&vpci_dev->dev_list[slot]);
        }

        pdev->pci_dev_data = vpci_dev;

        return 0;
}

int pciback_publish_pci_roots(struct pciback_device *pdev,
                              publish_pci_root_cb publish_cb)
{
        /* The Virtual PCI bus has only one root */
        return publish_cb(pdev, 0, 0);
}

void pciback_release_devices(struct pciback_device *pdev)
{
        int slot;
        struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;

        for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
                struct pci_dev_entry *e, *tmp;
                list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
                                         list) {
                        list_del(&e->list);
                        pcistub_put_pci_dev(e->dev);
                        kfree(e);
                }
        }

        kfree(vpci_dev);
        pdev->pci_dev_data = NULL;
}