iov.c

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/*
 * drivers/pci/iov.c
 *
 * Copyright (C) 2009 Intel Corporation, Yu Zhao <[email protected]>
 *
 * PCI Express I/O Virtualization (IOV) support.
 *   Single Root IOV 1.0
 *   Address Translation Service 1.0
 */

#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/export.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/pci-ats.h>
#include "pci.h"

#define VIRTFN_ID_LEN   16

static inline u8 virtfn_bus(struct pci_dev *dev, int id)
{
    return dev->bus->number + ((dev->devfn + dev->sriov->offset +
                    dev->sriov->stride * id) >> 8);
}

static inline u8 virtfn_devfn(struct pci_dev *dev, int id)
{
    return (dev->devfn + dev->sriov->offset +
        dev->sriov->stride * id) & 0xff;
}

static struct pci_bus *virtfn_add_bus(struct pci_bus *bus, int busnr)
{
    int rc;
    struct pci_bus *child;

    if (bus->number == busnr)
        return bus;

    child = pci_find_bus(pci_domain_nr(bus), busnr);
    if (child)
        return child;

    child = pci_add_new_bus(bus, NULL, busnr);
    if (!child)
        return NULL;

    pci_bus_insert_busn_res(child, busnr, busnr);
    child->dev.parent = bus->bridge;
    rc = pci_bus_add_child(child);
    if (rc) {
        pci_remove_bus(child);
        return NULL;
    }

    return child;
}

static void virtfn_remove_bus(struct pci_bus *bus, int busnr)
{
    struct pci_bus *child;

    if (bus->number == busnr)
        return;

    child = pci_find_bus(pci_domain_nr(bus), busnr);
    BUG_ON(!child);

    if (list_empty(&child->devices))
        pci_remove_bus(child);
}

static int virtfn_add(struct pci_dev *dev, int id, int reset)
{
    int i;
    int rc;
    u64 size;
    char buf[VIRTFN_ID_LEN];
    struct pci_dev *virtfn;
    struct resource *res;
    struct pci_sriov *iov = dev->sriov;

    virtfn = alloc_pci_dev();
    if (!virtfn)
        return -ENOMEM;

    mutex_lock(&iov->dev->sriov->lock);
    virtfn->bus = virtfn_add_bus(dev->bus, virtfn_bus(dev, id));
    if (!virtfn->bus) {
        kfree(virtfn);
        mutex_unlock(&iov->dev->sriov->lock);
        return -ENOMEM;
    }
    virtfn->devfn = virtfn_devfn(dev, id);
    virtfn->vendor = dev->vendor;
    pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_DID, &virtfn->device);
    pci_setup_device(virtfn);
    virtfn->dev.parent = dev->dev.parent;

    for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
        res = dev->resource + PCI_IOV_RESOURCES + i;
        if (!res->parent)
            continue;
        virtfn->resource[i].name = pci_name(virtfn);
        virtfn->resource[i].flags = res->flags;
        size = resource_size(res);
        do_div(size, iov->total);
        virtfn->resource[i].start = res->start + size * id;
        virtfn->resource[i].end = virtfn->resource[i].start + size - 1;
        rc = request_resource(res, &virtfn->resource[i]);
        BUG_ON(rc);
    }

    if (reset)
        __pci_reset_function(virtfn);

    pci_device_add(virtfn, virtfn->bus);
    mutex_unlock(&iov->dev->sriov->lock);

    virtfn->physfn = pci_dev_get(dev);
    virtfn->is_virtfn = 1;

    rc = pci_bus_add_device(virtfn);
    if (rc)
        goto failed1;
    sprintf(buf, "virtfn%u", id);
    rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);
    if (rc)
        goto failed1;
    rc = sysfs_create_link(&virtfn->dev.kobj, &dev->dev.kobj, "physfn");
    if (rc)
        goto failed2;

    kobject_uevent(&virtfn->dev.kobj, KOBJ_CHANGE);

    return 0;

failed2:
    sysfs_remove_link(&dev->dev.kobj, buf);
failed1:
    pci_dev_put(dev);
    mutex_lock(&iov->dev->sriov->lock);
    pci_stop_and_remove_bus_device(virtfn);
    virtfn_remove_bus(dev->bus, virtfn_bus(dev, id));
    mutex_unlock(&iov->dev->sriov->lock);

    return rc;
}

static void virtfn_remove(struct pci_dev *dev, int id, int reset)
{
    char buf[VIRTFN_ID_LEN];
    struct pci_bus *bus;
    struct pci_dev *virtfn;
    struct pci_sriov *iov = dev->sriov;

    bus = pci_find_bus(pci_domain_nr(dev->bus), virtfn_bus(dev, id));
    if (!bus)
        return;

    virtfn = pci_get_slot(bus, virtfn_devfn(dev, id));
    if (!virtfn)
        return;

    pci_dev_put(virtfn);

    if (reset) {
        device_release_driver(&virtfn->dev);
        __pci_reset_function(virtfn);
    }

    sprintf(buf, "virtfn%u", id);
    sysfs_remove_link(&dev->dev.kobj, buf);
    /*
     * pci_stop_dev() could have been called for this virtfn already,
     * so the directory for the virtfn may have been removed before.
     * Double check to avoid spurious sysfs warnings.
     */
    if (virtfn->dev.kobj.sd)
        sysfs_remove_link(&virtfn->dev.kobj, "physfn");

    mutex_lock(&iov->dev->sriov->lock);
    pci_stop_and_remove_bus_device(virtfn);
    virtfn_remove_bus(dev->bus, virtfn_bus(dev, id));
    mutex_unlock(&iov->dev->sriov->lock);

    pci_dev_put(dev);
}

static int sriov_migration(struct pci_dev *dev)
{
    u16 status;
    struct pci_sriov *iov = dev->sriov;

    if (!iov->nr_virtfn)
        return 0;

    if (!(iov->cap & PCI_SRIOV_CAP_VFM))
        return 0;

    pci_read_config_word(dev, iov->pos + PCI_SRIOV_STATUS, &status);
    if (!(status & PCI_SRIOV_STATUS_VFM))
        return 0;

    schedule_work(&iov->mtask);

    return 1;
}

static void sriov_migration_task(struct work_struct *work)
{
    int i;
    u8 state;
    u16 status;
    struct pci_sriov *iov = container_of(work, struct pci_sriov, mtask);

    for (i = iov->initial; i < iov->nr_virtfn; i++) {
        state = readb(iov->mstate + i);
        if (state == PCI_SRIOV_VFM_MI) {
            writeb(PCI_SRIOV_VFM_AV, iov->mstate + i);
            state = readb(iov->mstate + i);
            if (state == PCI_SRIOV_VFM_AV)
                virtfn_add(iov->self, i, 1);
        } else if (state == PCI_SRIOV_VFM_MO) {
            virtfn_remove(iov->self, i, 1);
            writeb(PCI_SRIOV_VFM_UA, iov->mstate + i);
            state = readb(iov->mstate + i);
            if (state == PCI_SRIOV_VFM_AV)
                virtfn_add(iov->self, i, 0);
        }
    }

    pci_read_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, &status);
    status &= ~PCI_SRIOV_STATUS_VFM;
    pci_write_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, status);
}

static int sriov_enable_migration(struct pci_dev *dev, int nr_virtfn)
{
    int bir;
    u32 table;
    resource_size_t pa;
    struct pci_sriov *iov = dev->sriov;

    if (nr_virtfn <= iov->initial)
        return 0;

    pci_read_config_dword(dev, iov->pos + PCI_SRIOV_VFM, &table);
    bir = PCI_SRIOV_VFM_BIR(table);
    if (bir > PCI_STD_RESOURCE_END)
        return -EIO;

    table = PCI_SRIOV_VFM_OFFSET(table);
    if (table + nr_virtfn > pci_resource_len(dev, bir))
        return -EIO;

    pa = pci_resource_start(dev, bir) + table;
    iov->mstate = ioremap(pa, nr_virtfn);
    if (!iov->mstate)
        return -ENOMEM;

    INIT_WORK(&iov->mtask, sriov_migration_task);

    iov->ctrl |= PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR;
    pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);

    return 0;
}

static void sriov_disable_migration(struct pci_dev *dev)
{
    struct pci_sriov *iov = dev->sriov;

    iov->ctrl &= ~(PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR);
    pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);

    cancel_work_sync(&iov->mtask);
    iounmap(iov->mstate);
}

static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
{
    int rc;
    int i, j;
    int nres;
    u16 offset, stride, initial;
    struct resource *res;
    struct pci_dev *pdev;
    struct pci_sriov *iov = dev->sriov;
    int bars = 0;

    if (!nr_virtfn)
        return 0;

    if (iov->nr_virtfn)
        return -EINVAL;

    pci_read_config_word(dev, iov->pos + PCI_SRIOV_INITIAL_VF, &initial);
    if (initial > iov->total ||
        (!(iov->cap & PCI_SRIOV_CAP_VFM) && (initial != iov->total)))
        return -EIO;

    if (nr_virtfn < 0 || nr_virtfn > iov->total ||
        (!(iov->cap & PCI_SRIOV_CAP_VFM) && (nr_virtfn > initial)))
        return -EINVAL;

    pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, nr_virtfn);
    pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_OFFSET, &offset);
    pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_STRIDE, &stride);
    if (!offset || (nr_virtfn > 1 && !stride))
        return -EIO;

    nres = 0;
    for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
        bars |= (1 << (i + PCI_IOV_RESOURCES));
        res = dev->resource + PCI_IOV_RESOURCES + i;
        if (res->parent)
            nres++;
    }
    if (nres != iov->nres) {
        dev_err(&dev->dev, "not enough MMIO resources for SR-IOV\n");
        return -ENOMEM;
    }

    iov->offset = offset;
    iov->stride = stride;

    if (virtfn_bus(dev, nr_virtfn - 1) > dev->bus->busn_res.end) {
        dev_err(&dev->dev, "SR-IOV: bus number out of range\n");
        return -ENOMEM;
    }

    if (pci_enable_resources(dev, bars)) {
        dev_err(&dev->dev, "SR-IOV: IOV BARS not allocated\n");
        return -ENOMEM;
    }

    if (iov->link != dev->devfn) {
        pdev = pci_get_slot(dev->bus, iov->link);
        if (!pdev)
            return -ENODEV;

        pci_dev_put(pdev);

        if (!pdev->is_physfn)
            return -ENODEV;

        rc = sysfs_create_link(&dev->dev.kobj,
                    &pdev->dev.kobj, "dep_link");
        if (rc)
            return rc;
    }

    iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
    pci_cfg_access_lock(dev);
    pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
    msleep(100);
    pci_cfg_access_unlock(dev);

    iov->initial = initial;
    if (nr_virtfn < initial)
        initial = nr_virtfn;

    for (i = 0; i < initial; i++) {
        rc = virtfn_add(dev, i, 0);
        if (rc)
            goto failed;
    }

    if (iov->cap & PCI_SRIOV_CAP_VFM) {
        rc = sriov_enable_migration(dev, nr_virtfn);
        if (rc)
            goto failed;
    }

    kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
    iov->nr_virtfn = nr_virtfn;

    return 0;

failed:
    for (j = 0; j < i; j++)
        virtfn_remove(dev, j, 0);

    iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
    pci_cfg_access_lock(dev);
    pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
    ssleep(1);
    pci_cfg_access_unlock(dev);

    if (iov->link != dev->devfn)
        sysfs_remove_link(&dev->dev.kobj, "dep_link");

    return rc;
}

static void sriov_disable(struct pci_dev *dev)
{
    int i;
    struct pci_sriov *iov = dev->sriov;

    if (!iov->nr_virtfn)
        return;

    if (iov->cap & PCI_SRIOV_CAP_VFM)
        sriov_disable_migration(dev);

    for (i = 0; i < iov->nr_virtfn; i++)
        virtfn_remove(dev, i, 0);

    iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
    pci_cfg_access_lock(dev);
    pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
    ssleep(1);
    pci_cfg_access_unlock(dev);

    if (iov->link != dev->devfn)
        sysfs_remove_link(&dev->dev.kobj, "dep_link");

    iov->nr_virtfn = 0;
}

static int sriov_init(struct pci_dev *dev, int pos)
{
    int i;
    int rc;
    int nres;
    u32 pgsz;
    u16 ctrl, total, offset, stride;
    struct pci_sriov *iov;
    struct resource *res;
    struct pci_dev *pdev;

    if (pci_pcie_type(dev) != PCI_EXP_TYPE_RC_END &&
        pci_pcie_type(dev) != PCI_EXP_TYPE_ENDPOINT)
        return -ENODEV;

    pci_read_config_word(dev, pos + PCI_SRIOV_CTRL, &ctrl);
    if (ctrl & PCI_SRIOV_CTRL_VFE) {
        pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, 0);
        ssleep(1);
    }

    pci_read_config_word(dev, pos + PCI_SRIOV_TOTAL_VF, &total);
    if (!total)
        return 0;

    ctrl = 0;
    list_for_each_entry(pdev, &dev->bus->devices, bus_list)
        if (pdev->is_physfn)
            goto found;

    pdev = NULL;
    if (pci_ari_enabled(dev->bus))
        ctrl |= PCI_SRIOV_CTRL_ARI;

found:
    pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
    pci_read_config_word(dev, pos + PCI_SRIOV_VF_OFFSET, &offset);
    pci_read_config_word(dev, pos + PCI_SRIOV_VF_STRIDE, &stride);
    if (!offset || (total > 1 && !stride))
        return -EIO;

    pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz);
    i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0;
    pgsz &= ~((1 << i) - 1);
    if (!pgsz)
        return -EIO;

    pgsz &= ~(pgsz - 1);
    pci_write_config_dword(dev, pos + PCI_SRIOV_SYS_PGSIZE, pgsz);

    nres = 0;
    for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
        res = dev->resource + PCI_IOV_RESOURCES + i;
        i += __pci_read_base(dev, pci_bar_unknown, res,
                     pos + PCI_SRIOV_BAR + i * 4);
        if (!res->flags)
            continue;
        if (resource_size(res) & (PAGE_SIZE - 1)) {
            rc = -EIO;
            goto failed;
        }
        res->end = res->start + resource_size(res) * total - 1;
        nres++;
    }

    iov = kzalloc(sizeof(*iov), GFP_KERNEL);
    if (!iov) {
        rc = -ENOMEM;
        goto failed;
    }

    iov->pos = pos;
    iov->nres = nres;
    iov->ctrl = ctrl;
    iov->total = total;
    iov->offset = offset;
    iov->stride = stride;
    iov->pgsz = pgsz;
    iov->self = dev;
    pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
    pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link);
    if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
        iov->link = PCI_DEVFN(PCI_SLOT(dev->devfn), iov->link);

    if (pdev)
        iov->dev = pci_dev_get(pdev);
    else
        iov->dev = dev;

    mutex_init(&iov->lock);

    dev->sriov = iov;
    dev->is_physfn = 1;

    return 0;

failed:
    for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
        res = dev->resource + PCI_IOV_RESOURCES + i;
        res->flags = 0;
    }

    return rc;
}

static void sriov_release(struct pci_dev *dev)
{
    BUG_ON(dev->sriov->nr_virtfn);

    if (dev != dev->sriov->dev)
        pci_dev_put(dev->sriov->dev);

    mutex_destroy(&dev->sriov->lock);

    kfree(dev->sriov);
    dev->sriov = NULL;
}

static void sriov_restore_state(struct pci_dev *dev)
{
    int i;
    u16 ctrl;
    struct pci_sriov *iov = dev->sriov;

    pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &ctrl);
    if (ctrl & PCI_SRIOV_CTRL_VFE)
        return;

    for (i = PCI_IOV_RESOURCES; i <= PCI_IOV_RESOURCE_END; i++)
        pci_update_resource(dev, i);

    pci_write_config_dword(dev, iov->pos + PCI_SRIOV_SYS_PGSIZE, iov->pgsz);
    pci_write_config_word(dev, iov->pos + PCI_SRIOV_NUM_VF, iov->nr_virtfn);
    pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
    if (iov->ctrl & PCI_SRIOV_CTRL_VFE)
        msleep(100);
}

int pci_iov_init(struct pci_dev *dev)
{
    int pos;

    if (!pci_is_pcie(dev))
        return -ENODEV;

    pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
    if (pos)
        return sriov_init(dev, pos);

    return -ENODEV;
}

void pci_iov_release(struct pci_dev *dev)
{
    if (dev->is_physfn)
        sriov_release(dev);
}

int pci_iov_resource_bar(struct pci_dev *dev, int resno,
             enum pci_bar_type *type)
{
    if (resno < PCI_IOV_RESOURCES || resno > PCI_IOV_RESOURCE_END)
        return 0;

    BUG_ON(!dev->is_physfn);

    *type = pci_bar_unknown;

    return dev->sriov->pos + PCI_SRIOV_BAR +
        4 * (resno - PCI_IOV_RESOURCES);
}

resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
{
    struct resource tmp;
    enum pci_bar_type type;
    int reg = pci_iov_resource_bar(dev, resno, &type);
    
    if (!reg)
        return 0;

     __pci_read_base(dev, type, &tmp, reg);
    return resource_alignment(&tmp);
}

void pci_restore_iov_state(struct pci_dev *dev)
{
    if (dev->is_physfn)
        sriov_restore_state(dev);
}

int pci_iov_bus_range(struct pci_bus *bus)
{
    int max = 0;
    u8 busnr;
    struct pci_dev *dev;

    list_for_each_entry(dev, &bus->devices, bus_list) {
        if (!dev->is_physfn)
            continue;
        busnr = virtfn_bus(dev, dev->sriov->total - 1);
        if (busnr > max)
            max = busnr;
    }

    return max ? max - bus->number : 0;
}

int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
{
    might_sleep();

    if (!dev->is_physfn)
        return -ENODEV;

    return sriov_enable(dev, nr_virtfn);
}
EXPORT_SYMBOL_GPL(pci_enable_sriov);

void pci_disable_sriov(struct pci_dev *dev)
{
    might_sleep();

    if (!dev->is_physfn)
        return;

    sriov_disable(dev);
}
EXPORT_SYMBOL_GPL(pci_disable_sriov);

irqreturn_t pci_sriov_migration(struct pci_dev *dev)
{
    if (!dev->is_physfn)
        return IRQ_NONE;

    return sriov_migration(dev) ? IRQ_HANDLED : IRQ_NONE;
}
EXPORT_SYMBOL_GPL(pci_sriov_migration);

int pci_num_vf(struct pci_dev *dev)
{
    if (!dev || !dev->is_physfn)
        return 0;
    else
        return dev->sriov->nr_virtfn;
}
EXPORT_SYMBOL_GPL(pci_num_vf);