drivers/pci/iov.c - maze/linux - Git at Google

 /*
  * drivers/pci/iov.c
  *
  * Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
  *
  * 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 (dev->pcie_type != PCI_EXP_TYPE_RC_END &&
 	    dev->pcie_type != 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 (dev->pcie_type == 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);
 }

 /**
  * pci_iov_init - initialize the IOV capability
  * @dev: the PCI device
  *
  * Returns 0 on success, or negative on failure.
  */
 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;
 }

 /**
  * pci_iov_release - release resources used by the IOV capability
  * @dev: the PCI device
  */
 void pci_iov_release(struct pci_dev *dev)
 {
 	if (dev->is_physfn)
 		sriov_release(dev);
 }

 /**
  * pci_iov_resource_bar - get position of the SR-IOV BAR
  * @dev: the PCI device
  * @resno: the resource number
  * @type: the BAR type to be filled in
  *
  * Returns position of the BAR encapsulated in the SR-IOV capability.
  */
 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);
 }

 /**
  * pci_sriov_resource_alignment - get resource alignment for VF BAR
  * @dev: the PCI device
  * @resno: the resource number
  *
  * Returns the alignment of the VF BAR found in the SR-IOV capability.
  * This is not the same as the resource size which is defined as
  * the VF BAR size multiplied by the number of VFs.  The alignment
  * is just the VF BAR size.
  */
 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);
 }

 /**
  * pci_restore_iov_state - restore the state of the IOV capability
  * @dev: the PCI device
  */
 void pci_restore_iov_state(struct pci_dev *dev)
 {
 	if (dev->is_physfn)
 		sriov_restore_state(dev);
 }

 /**
  * pci_iov_bus_range - find bus range used by Virtual Function
  * @bus: the PCI bus
  *
  * Returns max number of buses (exclude current one) used by Virtual
  * Functions.
  */
 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;
 }

 /**
  * pci_enable_sriov - enable the SR-IOV capability
  * @dev: the PCI device
  * @nr_virtfn: number of virtual functions to enable
  *
  * Returns 0 on success, or negative on failure.
  */
 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);

 /**
  * pci_disable_sriov - disable the SR-IOV capability
  * @dev: the PCI device
  */
 void pci_disable_sriov(struct pci_dev *dev)
 {
 	might_sleep();

 	if (!dev->is_physfn)
 		return;

 	sriov_disable(dev);
 }
 EXPORT_SYMBOL_GPL(pci_disable_sriov);

 /**
  * pci_sriov_migration - notify SR-IOV core of Virtual Function Migration
  * @dev: the PCI device
  *
  * Returns IRQ_HANDLED if the IRQ is handled, or IRQ_NONE if not.
  *
  * Physical Function driver is responsible to register IRQ handler using
  * VF Migration Interrupt Message Number, and call this function when the
  * interrupt is generated by the hardware.
  */
 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);

 /**
  * pci_num_vf - return number of VFs associated with a PF device_release_driver
  * @dev: the PCI device
  *
  * Returns number of VFs, or 0 if SR-IOV is not enabled.
  */
 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);
	/*
	* drivers/pci/iov.c
	*
	* Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
	*
	* 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 (dev->pcie_type != PCI_EXP_TYPE_RC_END &&
	dev->pcie_type != 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 (dev->pcie_type == 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);
	}

	/**
	* pci_iov_init - initialize the IOV capability
	* @dev: the PCI device
	*
	* Returns 0 on success, or negative on failure.
	*/
	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;
	}

	/**
	* pci_iov_release - release resources used by the IOV capability
	* @dev: the PCI device
	*/
	void pci_iov_release(struct pci_dev *dev)
	{
	if (dev->is_physfn)
	sriov_release(dev);
	}

	/**
	* pci_iov_resource_bar - get position of the SR-IOV BAR
	* @dev: the PCI device
	* @resno: the resource number
	* @type: the BAR type to be filled in
	*
	* Returns position of the BAR encapsulated in the SR-IOV capability.
	*/
	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);
	}

	/**
	* pci_sriov_resource_alignment - get resource alignment for VF BAR
	* @dev: the PCI device
	* @resno: the resource number
	*
	* Returns the alignment of the VF BAR found in the SR-IOV capability.
	* This is not the same as the resource size which is defined as
	* the VF BAR size multiplied by the number of VFs. The alignment
	* is just the VF BAR size.
	*/
	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);
	}

	/**
	* pci_restore_iov_state - restore the state of the IOV capability
	* @dev: the PCI device
	*/
	void pci_restore_iov_state(struct pci_dev *dev)
	{
	if (dev->is_physfn)
	sriov_restore_state(dev);
	}

	/**
	* pci_iov_bus_range - find bus range used by Virtual Function
	* @bus: the PCI bus
	*
	* Returns max number of buses (exclude current one) used by Virtual
	* Functions.
	*/
	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;
	}

	/**
	* pci_enable_sriov - enable the SR-IOV capability
	* @dev: the PCI device
	* @nr_virtfn: number of virtual functions to enable
	*
	* Returns 0 on success, or negative on failure.
	*/
	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);

	/**
	* pci_disable_sriov - disable the SR-IOV capability
	* @dev: the PCI device
	*/
	void pci_disable_sriov(struct pci_dev *dev)
	{
	might_sleep();

	if (!dev->is_physfn)
	return;

	sriov_disable(dev);
	}
	EXPORT_SYMBOL_GPL(pci_disable_sriov);

	/**
	* pci_sriov_migration - notify SR-IOV core of Virtual Function Migration
	* @dev: the PCI device
	*
	* Returns IRQ_HANDLED if the IRQ is handled, or IRQ_NONE if not.
	*
	* Physical Function driver is responsible to register IRQ handler using
	* VF Migration Interrupt Message Number, and call this function when the
	* interrupt is generated by the hardware.
	*/
	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);

	/**
	* pci_num_vf - return number of VFs associated with a PF device_release_driver
	* @dev: the PCI device
	*
	* Returns number of VFs, or 0 if SR-IOV is not enabled.
	*/
	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);