powerpc/pseries: Move vio.c into platforms pseries

vio.c is pseries only code, so move it in there.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 1705 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c
new file mode 100644
index 000000000000..2c8fb3ec989e
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/vio.c
@@ -0,0 +1,1705 @@
+/*
+ * IBM PowerPC Virtual I/O Infrastructure Support.
+ *
+ *    Copyright (c) 2003,2008 IBM Corp.
+ *     Dave Engebretsen engebret@us.ibm.com
+ *     Santiago Leon santil@us.ibm.com
+ *     Hollis Blanchard <hollisb@us.ibm.com>
+ *     Stephen Rothwell
+ *     Robert Jennings <rcjenn@us.ibm.com>
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/cpu.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/stat.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/console.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/dma-mapping.h>
+#include <linux/kobject.h>
+
+#include <asm/iommu.h>
+#include <asm/dma.h>
+#include <asm/vio.h>
+#include <asm/prom.h>
+#include <asm/firmware.h>
+#include <asm/tce.h>
+#include <asm/page.h>
+#include <asm/hvcall.h>
+
+static struct vio_dev vio_bus_device  = { /* fake "parent" device */
+	.name = "vio",
+	.type = "",
+	.dev.init_name = "vio",
+	.dev.bus = &vio_bus_type,
+};
+
+#ifdef CONFIG_PPC_SMLPAR
+/**
+ * vio_cmo_pool - A pool of IO memory for CMO use
+ *
+ * @size: The size of the pool in bytes
+ * @free: The amount of free memory in the pool
+ */
+struct vio_cmo_pool {
+	size_t size;
+	size_t free;
+};
+
+/* How many ms to delay queued balance work */
+#define VIO_CMO_BALANCE_DELAY 100
+
+/* Portion out IO memory to CMO devices by this chunk size */
+#define VIO_CMO_BALANCE_CHUNK 131072
+
+/**
+ * vio_cmo_dev_entry - A device that is CMO-enabled and requires entitlement
+ *
+ * @vio_dev: struct vio_dev pointer
+ * @list: pointer to other devices on bus that are being tracked
+ */
+struct vio_cmo_dev_entry {
+	struct vio_dev *viodev;
+	struct list_head list;
+};
+
+/**
+ * vio_cmo - VIO bus accounting structure for CMO entitlement
+ *
+ * @lock: spinlock for entire structure
+ * @balance_q: work queue for balancing system entitlement
+ * @device_list: list of CMO-enabled devices requiring entitlement
+ * @entitled: total system entitlement in bytes
+ * @reserve: pool of memory from which devices reserve entitlement, incl. spare
+ * @excess: pool of excess entitlement not needed for device reserves or spare
+ * @spare: IO memory for device hotplug functionality
+ * @min: minimum necessary for system operation
+ * @desired: desired memory for system operation
+ * @curr: bytes currently allocated
+ * @high: high water mark for IO data usage
+ */
+static struct vio_cmo {
+	spinlock_t lock;
+	struct delayed_work balance_q;
+	struct list_head device_list;
+	size_t entitled;
+	struct vio_cmo_pool reserve;
+	struct vio_cmo_pool excess;
+	size_t spare;
+	size_t min;
+	size_t desired;
+	size_t curr;
+	size_t high;
+} vio_cmo;
+
+/**
+ * vio_cmo_OF_devices - Count the number of OF devices that have DMA windows
+ */
+static int vio_cmo_num_OF_devs(void)
+{
+	struct device_node *node_vroot;
+	int count = 0;
+
+	/*
+	 * Count the number of vdevice entries with an
+	 * ibm,my-dma-window OF property
+	 */
+	node_vroot = of_find_node_by_name(NULL, "vdevice");
+	if (node_vroot) {
+		struct device_node *of_node;
+		struct property *prop;
+
+		for_each_child_of_node(node_vroot, of_node) {
+			prop = of_find_property(of_node, "ibm,my-dma-window",
+			                       NULL);
+			if (prop)
+				count++;
+		}
+	}
+	of_node_put(node_vroot);
+	return count;
+}
+
+/**
+ * vio_cmo_alloc - allocate IO memory for CMO-enable devices
+ *
+ * @viodev: VIO device requesting IO memory
+ * @size: size of allocation requested
+ *
+ * Allocations come from memory reserved for the devices and any excess
+ * IO memory available to all devices.  The spare pool used to service
+ * hotplug must be equal to %VIO_CMO_MIN_ENT for the excess pool to be
+ * made available.
+ *
+ * Return codes:
+ *  0 for successful allocation and -ENOMEM for a failure
+ */
+static inline int vio_cmo_alloc(struct vio_dev *viodev, size_t size)
+{
+	unsigned long flags;
+	size_t reserve_free = 0;
+	size_t excess_free = 0;
+	int ret = -ENOMEM;
+
+	spin_lock_irqsave(&vio_cmo.lock, flags);
+
+	/* Determine the amount of free entitlement available in reserve */
+	if (viodev->cmo.entitled > viodev->cmo.allocated)
+		reserve_free = viodev->cmo.entitled - viodev->cmo.allocated;
+
+	/* If spare is not fulfilled, the excess pool can not be used. */
+	if (vio_cmo.spare >= VIO_CMO_MIN_ENT)
+		excess_free = vio_cmo.excess.free;
+
+	/* The request can be satisfied */
+	if ((reserve_free + excess_free) >= size) {
+		vio_cmo.curr += size;
+		if (vio_cmo.curr > vio_cmo.high)
+			vio_cmo.high = vio_cmo.curr;
+		viodev->cmo.allocated += size;
+		size -= min(reserve_free, size);
+		vio_cmo.excess.free -= size;
+		ret = 0;
+	}
+
+	spin_unlock_irqrestore(&vio_cmo.lock, flags);
+	return ret;
+}
+
+/**
+ * vio_cmo_dealloc - deallocate IO memory from CMO-enable devices
+ * @viodev: VIO device freeing IO memory
+ * @size: size of deallocation
+ *
+ * IO memory is freed by the device back to the correct memory pools.
+ * The spare pool is replenished first from either memory pool, then
+ * the reserve pool is used to reduce device entitlement, the excess
+ * pool is used to increase the reserve pool toward the desired entitlement
+ * target, and then the remaining memory is returned to the pools.
+ *
+ */
+static inline void vio_cmo_dealloc(struct vio_dev *viodev, size_t size)
+{
+	unsigned long flags;
+	size_t spare_needed = 0;
+	size_t excess_freed = 0;
+	size_t reserve_freed = size;
+	size_t tmp;
+	int balance = 0;
+
+	spin_lock_irqsave(&vio_cmo.lock, flags);
+	vio_cmo.curr -= size;
+
+	/* Amount of memory freed from the excess pool */
+	if (viodev->cmo.allocated > viodev->cmo.entitled) {
+		excess_freed = min(reserve_freed, (viodev->cmo.allocated -
+		                                   viodev->cmo.entitled));
+		reserve_freed -= excess_freed;
+	}
+
+	/* Remove allocation from device */
+	viodev->cmo.allocated -= (reserve_freed + excess_freed);
+
+	/* Spare is a subset of the reserve pool, replenish it first. */
+	spare_needed = VIO_CMO_MIN_ENT - vio_cmo.spare;
+
+	/*
+	 * Replenish the spare in the reserve pool from the excess pool.
+	 * This moves entitlement into the reserve pool.
+	 */
+	if (spare_needed && excess_freed) {
+		tmp = min(excess_freed, spare_needed);
+		vio_cmo.excess.size -= tmp;
+		vio_cmo.reserve.size += tmp;
+		vio_cmo.spare += tmp;
+		excess_freed -= tmp;
+		spare_needed -= tmp;
+		balance = 1;
+	}
+
+	/*
+	 * Replenish the spare in the reserve pool from the reserve pool.
+	 * This removes entitlement from the device down to VIO_CMO_MIN_ENT,
+	 * if needed, and gives it to the spare pool. The amount of used
+	 * memory in this pool does not change.
+	 */
+	if (spare_needed && reserve_freed) {
+		tmp = min3(spare_needed, reserve_freed, (viodev->cmo.entitled - VIO_CMO_MIN_ENT));
+
+		vio_cmo.spare += tmp;
+		viodev->cmo.entitled -= tmp;
+		reserve_freed -= tmp;
+		spare_needed -= tmp;
+		balance = 1;
+	}
+
+	/*
+	 * Increase the reserve pool until the desired allocation is met.
+	 * Move an allocation freed from the excess pool into the reserve
+	 * pool and schedule a balance operation.
+	 */
+	if (excess_freed && (vio_cmo.desired > vio_cmo.reserve.size)) {
+		tmp = min(excess_freed, (vio_cmo.desired - vio_cmo.reserve.size));
+
+		vio_cmo.excess.size -= tmp;
+		vio_cmo.reserve.size += tmp;
+		excess_freed -= tmp;
+		balance = 1;
+	}
+
+	/* Return memory from the excess pool to that pool */
+	if (excess_freed)
+		vio_cmo.excess.free += excess_freed;
+
+	if (balance)
+		schedule_delayed_work(&vio_cmo.balance_q, VIO_CMO_BALANCE_DELAY);
+	spin_unlock_irqrestore(&vio_cmo.lock, flags);
+}
+
+/**
+ * vio_cmo_entitlement_update - Manage system entitlement changes
+ *
+ * @new_entitlement: new system entitlement to attempt to accommodate
+ *
+ * Increases in entitlement will be used to fulfill the spare entitlement
+ * and the rest is given to the excess pool.  Decreases, if they are
+ * possible, come from the excess pool and from unused device entitlement
+ *
+ * Returns: 0 on success, -ENOMEM when change can not be made
+ */
+int vio_cmo_entitlement_update(size_t new_entitlement)
+{
+	struct vio_dev *viodev;
+	struct vio_cmo_dev_entry *dev_ent;
+	unsigned long flags;
+	size_t avail, delta, tmp;
+
+	spin_lock_irqsave(&vio_cmo.lock, flags);
+
+	/* Entitlement increases */
+	if (new_entitlement > vio_cmo.entitled) {
+		delta = new_entitlement - vio_cmo.entitled;
+
+		/* Fulfill spare allocation */
+		if (vio_cmo.spare < VIO_CMO_MIN_ENT) {
+			tmp = min(delta, (VIO_CMO_MIN_ENT - vio_cmo.spare));
+			vio_cmo.spare += tmp;
+			vio_cmo.reserve.size += tmp;
+			delta -= tmp;
+		}
+
+		/* Remaining new allocation goes to the excess pool */
+		vio_cmo.entitled += delta;
+		vio_cmo.excess.size += delta;
+		vio_cmo.excess.free += delta;
+
+		goto out;
+	}
+
+	/* Entitlement decreases */
+	delta = vio_cmo.entitled - new_entitlement;
+	avail = vio_cmo.excess.free;
+
+	/*
+	 * Need to check how much unused entitlement each device can
+	 * sacrifice to fulfill entitlement change.
+	 */
+	list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
+		if (avail >= delta)
+			break;
+
+		viodev = dev_ent->viodev;
+		if ((viodev->cmo.entitled > viodev->cmo.allocated) &&
+		    (viodev->cmo.entitled > VIO_CMO_MIN_ENT))
+				avail += viodev->cmo.entitled -
+				         max_t(size_t, viodev->cmo.allocated,
+				               VIO_CMO_MIN_ENT);
+	}
+
+	if (delta <= avail) {
+		vio_cmo.entitled -= delta;
+
+		/* Take entitlement from the excess pool first */
+		tmp = min(vio_cmo.excess.free, delta);
+		vio_cmo.excess.size -= tmp;
+		vio_cmo.excess.free -= tmp;
+		delta -= tmp;
+
+		/*
+		 * Remove all but VIO_CMO_MIN_ENT bytes from devices
+		 * until entitlement change is served
+		 */
+		list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
+			if (!delta)
+				break;
+
+			viodev = dev_ent->viodev;
+			tmp = 0;
+			if ((viodev->cmo.entitled > viodev->cmo.allocated) &&
+			    (viodev->cmo.entitled > VIO_CMO_MIN_ENT))
+				tmp = viodev->cmo.entitled -
+				      max_t(size_t, viodev->cmo.allocated,
+				            VIO_CMO_MIN_ENT);
+			viodev->cmo.entitled -= min(tmp, delta);
+			delta -= min(tmp, delta);
+		}
+	} else {
+		spin_unlock_irqrestore(&vio_cmo.lock, flags);
+		return -ENOMEM;
+	}
+
+out:
+	schedule_delayed_work(&vio_cmo.balance_q, 0);
+	spin_unlock_irqrestore(&vio_cmo.lock, flags);
+	return 0;
+}
+
+/**
+ * vio_cmo_balance - Balance entitlement among devices
+ *
+ * @work: work queue structure for this operation
+ *
+ * Any system entitlement above the minimum needed for devices, or
+ * already allocated to devices, can be distributed to the devices.
+ * The list of devices is iterated through to recalculate the desired
+ * entitlement level and to determine how much entitlement above the
+ * minimum entitlement is allocated to devices.
+ *
+ * Small chunks of the available entitlement are given to devices until
+ * their requirements are fulfilled or there is no entitlement left to give.
+ * Upon completion sizes of the reserve and excess pools are calculated.
+ *
+ * The system minimum entitlement level is also recalculated here.
+ * Entitlement will be reserved for devices even after vio_bus_remove to
+ * accommodate reloading the driver.  The OF tree is walked to count the
+ * number of devices present and this will remove entitlement for devices
+ * that have actually left the system after having vio_bus_remove called.
+ */
+static void vio_cmo_balance(struct work_struct *work)
+{
+	struct vio_cmo *cmo;
+	struct vio_dev *viodev;
+	struct vio_cmo_dev_entry *dev_ent;
+	unsigned long flags;
+	size_t avail = 0, level, chunk, need;
+	int devcount = 0, fulfilled;
+
+	cmo = container_of(work, struct vio_cmo, balance_q.work);
+
+	spin_lock_irqsave(&vio_cmo.lock, flags);
+
+	/* Calculate minimum entitlement and fulfill spare */
+	cmo->min = vio_cmo_num_OF_devs() * VIO_CMO_MIN_ENT;
+	BUG_ON(cmo->min > cmo->entitled);
+	cmo->spare = min_t(size_t, VIO_CMO_MIN_ENT, (cmo->entitled - cmo->min));
+	cmo->min += cmo->spare;
+	cmo->desired = cmo->min;
+
+	/*
+	 * Determine how much entitlement is available and reset device
+	 * entitlements
+	 */
+	avail = cmo->entitled - cmo->spare;
+	list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
+		viodev = dev_ent->viodev;
+		devcount++;
+		viodev->cmo.entitled = VIO_CMO_MIN_ENT;
+		cmo->desired += (viodev->cmo.desired - VIO_CMO_MIN_ENT);
+		avail -= max_t(size_t, viodev->cmo.allocated, VIO_CMO_MIN_ENT);
+	}
+
+	/*
+	 * Having provided each device with the minimum entitlement, loop
+	 * over the devices portioning out the remaining entitlement
+	 * until there is nothing left.
+	 */
+	level = VIO_CMO_MIN_ENT;
+	while (avail) {
+		fulfilled = 0;
+		list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
+			viodev = dev_ent->viodev;
+
+			if (viodev->cmo.desired <= level) {
+				fulfilled++;
+				continue;
+			}
+
+			/*
+			 * Give the device up to VIO_CMO_BALANCE_CHUNK
+			 * bytes of entitlement, but do not exceed the
+			 * desired level of entitlement for the device.
+			 */
+			chunk = min_t(size_t, avail, VIO_CMO_BALANCE_CHUNK);
+			chunk = min(chunk, (viodev->cmo.desired -
+			                    viodev->cmo.entitled));
+			viodev->cmo.entitled += chunk;
+
+			/*
+			 * If the memory for this entitlement increase was
+			 * already allocated to the device it does not come
+			 * from the available pool being portioned out.
+			 */
+			need = max(viodev->cmo.allocated, viodev->cmo.entitled)-
+			       max(viodev->cmo.allocated, level);
+			avail -= need;
+
+		}
+		if (fulfilled == devcount)
+			break;
+		level += VIO_CMO_BALANCE_CHUNK;
+	}
+
+	/* Calculate new reserve and excess pool sizes */
+	cmo->reserve.size = cmo->min;
+	cmo->excess.free = 0;
+	cmo->excess.size = 0;
+	need = 0;
+	list_for_each_entry(dev_ent, &vio_cmo.device_list, list) {
+		viodev = dev_ent->viodev;
+		/* Calculated reserve size above the minimum entitlement */
+		if (viodev->cmo.entitled)
+			cmo->reserve.size += (viodev->cmo.entitled -
+			                      VIO_CMO_MIN_ENT);
+		/* Calculated used excess entitlement */
+		if (viodev->cmo.allocated > viodev->cmo.entitled)
+			need += viodev->cmo.allocated - viodev->cmo.entitled;
+	}
+	cmo->excess.size = cmo->entitled - cmo->reserve.size;
+	cmo->excess.free = cmo->excess.size - need;
+
+	cancel_delayed_work(to_delayed_work(work));
+	spin_unlock_irqrestore(&vio_cmo.lock, flags);
+}
+
+static void *vio_dma_iommu_alloc_coherent(struct device *dev, size_t size,
+					  dma_addr_t *dma_handle, gfp_t flag,
+					  unsigned long attrs)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+	void *ret;
+
+	if (vio_cmo_alloc(viodev, roundup(size, PAGE_SIZE))) {
+		atomic_inc(&viodev->cmo.allocs_failed);
+		return NULL;
+	}
+
+	ret = dma_iommu_ops.alloc(dev, size, dma_handle, flag, attrs);
+	if (unlikely(ret == NULL)) {
+		vio_cmo_dealloc(viodev, roundup(size, PAGE_SIZE));
+		atomic_inc(&viodev->cmo.allocs_failed);
+	}
+
+	return ret;
+}
+
+static void vio_dma_iommu_free_coherent(struct device *dev, size_t size,
+					void *vaddr, dma_addr_t dma_handle,
+					unsigned long attrs)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+
+	dma_iommu_ops.free(dev, size, vaddr, dma_handle, attrs);
+
+	vio_cmo_dealloc(viodev, roundup(size, PAGE_SIZE));
+}
+
+static dma_addr_t vio_dma_iommu_map_page(struct device *dev, struct page *page,
+                                         unsigned long offset, size_t size,
+                                         enum dma_data_direction direction,
+                                         unsigned long attrs)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+	struct iommu_table *tbl;
+	dma_addr_t ret = DMA_ERROR_CODE;
+
+	tbl = get_iommu_table_base(dev);
+	if (vio_cmo_alloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl)))) {
+		atomic_inc(&viodev->cmo.allocs_failed);
+		return ret;
+	}
+
+	ret = dma_iommu_ops.map_page(dev, page, offset, size, direction, attrs);
+	if (unlikely(dma_mapping_error(dev, ret))) {
+		vio_cmo_dealloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl)));
+		atomic_inc(&viodev->cmo.allocs_failed);
+	}
+
+	return ret;
+}
+
+static void vio_dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
+				     size_t size,
+				     enum dma_data_direction direction,
+				     unsigned long attrs)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+	struct iommu_table *tbl;
+
+	tbl = get_iommu_table_base(dev);
+	dma_iommu_ops.unmap_page(dev, dma_handle, size, direction, attrs);
+
+	vio_cmo_dealloc(viodev, roundup(size, IOMMU_PAGE_SIZE(tbl)));
+}
+
+static int vio_dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
+                                int nelems, enum dma_data_direction direction,
+                                unsigned long attrs)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+	struct iommu_table *tbl;
+	struct scatterlist *sgl;
+	int ret, count;
+	size_t alloc_size = 0;
+
+	tbl = get_iommu_table_base(dev);
+	for_each_sg(sglist, sgl, nelems, count)
+		alloc_size += roundup(sgl->length, IOMMU_PAGE_SIZE(tbl));
+
+	if (vio_cmo_alloc(viodev, alloc_size)) {
+		atomic_inc(&viodev->cmo.allocs_failed);
+		return 0;
+	}
+
+	ret = dma_iommu_ops.map_sg(dev, sglist, nelems, direction, attrs);
+
+	if (unlikely(!ret)) {
+		vio_cmo_dealloc(viodev, alloc_size);
+		atomic_inc(&viodev->cmo.allocs_failed);
+		return ret;
+	}
+
+	for_each_sg(sglist, sgl, ret, count)
+		alloc_size -= roundup(sgl->dma_length, IOMMU_PAGE_SIZE(tbl));
+	if (alloc_size)
+		vio_cmo_dealloc(viodev, alloc_size);
+
+	return ret;
+}
+
+static void vio_dma_iommu_unmap_sg(struct device *dev,
+		struct scatterlist *sglist, int nelems,
+		enum dma_data_direction direction,
+		unsigned long attrs)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+	struct iommu_table *tbl;
+	struct scatterlist *sgl;
+	size_t alloc_size = 0;
+	int count;
+
+	tbl = get_iommu_table_base(dev);
+	for_each_sg(sglist, sgl, nelems, count)
+		alloc_size += roundup(sgl->dma_length, IOMMU_PAGE_SIZE(tbl));
+
+	dma_iommu_ops.unmap_sg(dev, sglist, nelems, direction, attrs);
+
+	vio_cmo_dealloc(viodev, alloc_size);
+}
+
+static int vio_dma_iommu_dma_supported(struct device *dev, u64 mask)
+{
+        return dma_iommu_ops.dma_supported(dev, mask);
+}
+
+static u64 vio_dma_get_required_mask(struct device *dev)
+{
+        return dma_iommu_ops.get_required_mask(dev);
+}
+
+static struct dma_map_ops vio_dma_mapping_ops = {
+	.alloc             = vio_dma_iommu_alloc_coherent,
+	.free              = vio_dma_iommu_free_coherent,
+	.mmap		   = dma_direct_mmap_coherent,
+	.map_sg            = vio_dma_iommu_map_sg,
+	.unmap_sg          = vio_dma_iommu_unmap_sg,
+	.map_page          = vio_dma_iommu_map_page,
+	.unmap_page        = vio_dma_iommu_unmap_page,
+	.dma_supported     = vio_dma_iommu_dma_supported,
+	.get_required_mask = vio_dma_get_required_mask,
+};
+
+/**
+ * vio_cmo_set_dev_desired - Set desired entitlement for a device
+ *
+ * @viodev: struct vio_dev for device to alter
+ * @desired: new desired entitlement level in bytes
+ *
+ * For use by devices to request a change to their entitlement at runtime or
+ * through sysfs.  The desired entitlement level is changed and a balancing
+ * of system resources is scheduled to run in the future.
+ */
+void vio_cmo_set_dev_desired(struct vio_dev *viodev, size_t desired)
+{
+	unsigned long flags;
+	struct vio_cmo_dev_entry *dev_ent;
+	int found = 0;
+
+	if (!firmware_has_feature(FW_FEATURE_CMO))
+		return;
+
+	spin_lock_irqsave(&vio_cmo.lock, flags);
+	if (desired < VIO_CMO_MIN_ENT)
+		desired = VIO_CMO_MIN_ENT;
+
+	/*
+	 * Changes will not be made for devices not in the device list.
+	 * If it is not in the device list, then no driver is loaded
+	 * for the device and it can not receive entitlement.
+	 */
+	list_for_each_entry(dev_ent, &vio_cmo.device_list, list)
+		if (viodev == dev_ent->viodev) {
+			found = 1;
+			break;
+		}
+	if (!found) {
+		spin_unlock_irqrestore(&vio_cmo.lock, flags);
+		return;
+	}
+
+	/* Increase/decrease in desired device entitlement */
+	if (desired >= viodev->cmo.desired) {
+		/* Just bump the bus and device values prior to a balance*/
+		vio_cmo.desired += desired - viodev->cmo.desired;
+		viodev->cmo.desired = desired;
+	} else {
+		/* Decrease bus and device values for desired entitlement */
+		vio_cmo.desired -= viodev->cmo.desired - desired;
+		viodev->cmo.desired = desired;
+		/*
+		 * If less entitlement is desired than current entitlement, move
+		 * any reserve memory in the change region to the excess pool.
+		 */
+		if (viodev->cmo.entitled > desired) {
+			vio_cmo.reserve.size -= viodev->cmo.entitled - desired;
+			vio_cmo.excess.size += viodev->cmo.entitled - desired;
+			/*
+			 * If entitlement moving from the reserve pool to the
+			 * excess pool is currently unused, add to the excess
+			 * free counter.
+			 */
+			if (viodev->cmo.allocated < viodev->cmo.entitled)
+				vio_cmo.excess.free += viodev->cmo.entitled -
+				                       max(viodev->cmo.allocated, desired);
+			viodev->cmo.entitled = desired;
+		}
+	}
+	schedule_delayed_work(&vio_cmo.balance_q, 0);
+	spin_unlock_irqrestore(&vio_cmo.lock, flags);
+}
+
+/**
+ * vio_cmo_bus_probe - Handle CMO specific bus probe activities
+ *
+ * @viodev - Pointer to struct vio_dev for device
+ *
+ * Determine the devices IO memory entitlement needs, attempting
+ * to satisfy the system minimum entitlement at first and scheduling
+ * a balance operation to take care of the rest at a later time.
+ *
+ * Returns: 0 on success, -EINVAL when device doesn't support CMO, and
+ *          -ENOMEM when entitlement is not available for device or
+ *          device entry.
+ *
+ */
+static int vio_cmo_bus_probe(struct vio_dev *viodev)
+{
+	struct vio_cmo_dev_entry *dev_ent;
+	struct device *dev = &viodev->dev;
+	struct iommu_table *tbl;
+	struct vio_driver *viodrv = to_vio_driver(dev->driver);
+	unsigned long flags;
+	size_t size;
+	bool dma_capable = false;
+
+	tbl = get_iommu_table_base(dev);
+
+	/* A device requires entitlement if it has a DMA window property */
+	switch (viodev->family) {
+	case VDEVICE:
+		if (of_get_property(viodev->dev.of_node,
+					"ibm,my-dma-window", NULL))
+			dma_capable = true;
+		break;
+	case PFO:
+		dma_capable = false;
+		break;
+	default:
+		dev_warn(dev, "unknown device family: %d\n", viodev->family);
+		BUG();
+		break;
+	}
+
+	/* Configure entitlement for the device. */
+	if (dma_capable) {
+		/* Check that the driver is CMO enabled and get desired DMA */
+		if (!viodrv->get_desired_dma) {
+			dev_err(dev, "%s: device driver does not support CMO\n",
+			        __func__);
+			return -EINVAL;
+		}
+
+		viodev->cmo.desired =
+			IOMMU_PAGE_ALIGN(viodrv->get_desired_dma(viodev), tbl);
+		if (viodev->cmo.desired < VIO_CMO_MIN_ENT)
+			viodev->cmo.desired = VIO_CMO_MIN_ENT;
+		size = VIO_CMO_MIN_ENT;
+
+		dev_ent = kmalloc(sizeof(struct vio_cmo_dev_entry),
+		                  GFP_KERNEL);
+		if (!dev_ent)
+			return -ENOMEM;
+
+		dev_ent->viodev = viodev;
+		spin_lock_irqsave(&vio_cmo.lock, flags);
+		list_add(&dev_ent->list, &vio_cmo.device_list);
+	} else {
+		viodev->cmo.desired = 0;
+		size = 0;
+		spin_lock_irqsave(&vio_cmo.lock, flags);
+	}
+
+	/*
+	 * If the needs for vio_cmo.min have not changed since they
+	 * were last set, the number of devices in the OF tree has
+	 * been constant and the IO memory for this is already in
+	 * the reserve pool.
+	 */
+	if (vio_cmo.min == ((vio_cmo_num_OF_devs() + 1) *
+	                    VIO_CMO_MIN_ENT)) {
+		/* Updated desired entitlement if device requires it */
+		if (size)
+			vio_cmo.desired += (viodev->cmo.desired -
+		                        VIO_CMO_MIN_ENT);
+	} else {
+		size_t tmp;
+
+		tmp = vio_cmo.spare + vio_cmo.excess.free;
+		if (tmp < size) {
+			dev_err(dev, "%s: insufficient free "
+			        "entitlement to add device. "
+			        "Need %lu, have %lu\n", __func__,
+				size, (vio_cmo.spare + tmp));
+			spin_unlock_irqrestore(&vio_cmo.lock, flags);
+			return -ENOMEM;
+		}
+
+		/* Use excess pool first to fulfill request */
+		tmp = min(size, vio_cmo.excess.free);
+		vio_cmo.excess.free -= tmp;
+		vio_cmo.excess.size -= tmp;
+		vio_cmo.reserve.size += tmp;
+
+		/* Use spare if excess pool was insufficient */
+		vio_cmo.spare -= size - tmp;
+
+		/* Update bus accounting */
+		vio_cmo.min += size;
+		vio_cmo.desired += viodev->cmo.desired;
+	}
+	spin_unlock_irqrestore(&vio_cmo.lock, flags);
+	return 0;
+}
+
+/**
+ * vio_cmo_bus_remove - Handle CMO specific bus removal activities
+ *
+ * @viodev - Pointer to struct vio_dev for device
+ *
+ * Remove the device from the cmo device list.  The minimum entitlement
+ * will be reserved for the device as long as it is in the system.  The
+ * rest of the entitlement the device had been allocated will be returned
+ * to the system.
+ */
+static void vio_cmo_bus_remove(struct vio_dev *viodev)
+{
+	struct vio_cmo_dev_entry *dev_ent;
+	unsigned long flags;
+	size_t tmp;
+
+	spin_lock_irqsave(&vio_cmo.lock, flags);
+	if (viodev->cmo.allocated) {
+		dev_err(&viodev->dev, "%s: device had %lu bytes of IO "
+		        "allocated after remove operation.\n",
+		        __func__, viodev->cmo.allocated);
+		BUG();
+	}
+
+	/*
+	 * Remove the device from the device list being maintained for
+	 * CMO enabled devices.
+	 */
+	list_for_each_entry(dev_ent, &vio_cmo.device_list, list)
+		if (viodev == dev_ent->viodev) {
+			list_del(&dev_ent->list);
+			kfree(dev_ent);
+			break;
+		}
+
+	/*
+	 * Devices may not require any entitlement and they do not need
+	 * to be processed.  Otherwise, return the device's entitlement
+	 * back to the pools.
+	 */
+	if (viodev->cmo.entitled) {
+		/*
+		 * This device has not yet left the OF tree, it's
+		 * minimum entitlement remains in vio_cmo.min and
+		 * vio_cmo.desired
+		 */
+		vio_cmo.desired -= (viodev->cmo.desired - VIO_CMO_MIN_ENT);
+
+		/*
+		 * Save min allocation for device in reserve as long
+		 * as it exists in OF tree as determined by later
+		 * balance operation
+		 */
+		viodev->cmo.entitled -= VIO_CMO_MIN_ENT;
+
+		/* Replenish spare from freed reserve pool */
+		if (viodev->cmo.entitled && (vio_cmo.spare < VIO_CMO_MIN_ENT)) {
+			tmp = min(viodev->cmo.entitled, (VIO_CMO_MIN_ENT -
+			                                 vio_cmo.spare));
+			vio_cmo.spare += tmp;
+			viodev->cmo.entitled -= tmp;
+		}
+
+		/* Remaining reserve goes to excess pool */
+		vio_cmo.excess.size += viodev->cmo.entitled;
+		vio_cmo.excess.free += viodev->cmo.entitled;
+		vio_cmo.reserve.size -= viodev->cmo.entitled;
+
+		/*
+		 * Until the device is removed it will keep a
+		 * minimum entitlement; this will guarantee that
+		 * a module unload/load will result in a success.
+		 */
+		viodev->cmo.entitled = VIO_CMO_MIN_ENT;
+		viodev->cmo.desired = VIO_CMO_MIN_ENT;
+		atomic_set(&viodev->cmo.allocs_failed, 0);
+	}
+
+	spin_unlock_irqrestore(&vio_cmo.lock, flags);
+}
+
+static void vio_cmo_set_dma_ops(struct vio_dev *viodev)
+{
+	set_dma_ops(&viodev->dev, &vio_dma_mapping_ops);
+}
+
+/**
+ * vio_cmo_bus_init - CMO entitlement initialization at bus init time
+ *
+ * Set up the reserve and excess entitlement pools based on available
+ * system entitlement and the number of devices in the OF tree that
+ * require entitlement in the reserve pool.
+ */
+static void vio_cmo_bus_init(void)
+{
+	struct hvcall_mpp_data mpp_data;
+	int err;
+
+	memset(&vio_cmo, 0, sizeof(struct vio_cmo));
+	spin_lock_init(&vio_cmo.lock);
+	INIT_LIST_HEAD(&vio_cmo.device_list);
+	INIT_DELAYED_WORK(&vio_cmo.balance_q, vio_cmo_balance);
+
+	/* Get current system entitlement */
+	err = h_get_mpp(&mpp_data);
+
+	/*
+	 * On failure, continue with entitlement set to 0, will panic()
+	 * later when spare is reserved.
+	 */
+	if (err != H_SUCCESS) {
+		printk(KERN_ERR "%s: unable to determine system IO "\
+		       "entitlement. (%d)\n", __func__, err);
+		vio_cmo.entitled = 0;
+	} else {
+		vio_cmo.entitled = mpp_data.entitled_mem;
+	}
+
+	/* Set reservation and check against entitlement */
+	vio_cmo.spare = VIO_CMO_MIN_ENT;
+	vio_cmo.reserve.size = vio_cmo.spare;
+	vio_cmo.reserve.size += (vio_cmo_num_OF_devs() *
+	                         VIO_CMO_MIN_ENT);
+	if (vio_cmo.reserve.size > vio_cmo.entitled) {
+		printk(KERN_ERR "%s: insufficient system entitlement\n",
+		       __func__);
+		panic("%s: Insufficient system entitlement", __func__);
+	}
+
+	/* Set the remaining accounting variables */
+	vio_cmo.excess.size = vio_cmo.entitled - vio_cmo.reserve.size;
+	vio_cmo.excess.free = vio_cmo.excess.size;
+	vio_cmo.min = vio_cmo.reserve.size;
+	vio_cmo.desired = vio_cmo.reserve.size;
+}
+
+/* sysfs device functions and data structures for CMO */
+
+#define viodev_cmo_rd_attr(name)                                        \
+static ssize_t viodev_cmo_##name##_show(struct device *dev,             \
+                                        struct device_attribute *attr,  \
+                                         char *buf)                     \
+{                                                                       \
+	return sprintf(buf, "%lu\n", to_vio_dev(dev)->cmo.name);        \
+}
+
+static ssize_t viodev_cmo_allocs_failed_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+	return sprintf(buf, "%d\n", atomic_read(&viodev->cmo.allocs_failed));
+}
+
+static ssize_t viodev_cmo_allocs_failed_reset(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+	atomic_set(&viodev->cmo.allocs_failed, 0);
+	return count;
+}
+
+static ssize_t viodev_cmo_desired_set(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+	size_t new_desired;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &new_desired);
+	if (ret)
+		return ret;
+
+	vio_cmo_set_dev_desired(viodev, new_desired);
+	return count;
+}
+
+viodev_cmo_rd_attr(desired);
+viodev_cmo_rd_attr(entitled);
+viodev_cmo_rd_attr(allocated);
+
+static ssize_t name_show(struct device *, struct device_attribute *, char *);
+static ssize_t devspec_show(struct device *, struct device_attribute *, char *);
+static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
+			     char *buf);
+static struct device_attribute vio_cmo_dev_attrs[] = {
+	__ATTR_RO(name),
+	__ATTR_RO(devspec),
+	__ATTR_RO(modalias),
+	__ATTR(cmo_desired,       S_IWUSR|S_IRUSR|S_IWGRP|S_IRGRP|S_IROTH,
+	       viodev_cmo_desired_show, viodev_cmo_desired_set),
+	__ATTR(cmo_entitled,      S_IRUGO, viodev_cmo_entitled_show,      NULL),
+	__ATTR(cmo_allocated,     S_IRUGO, viodev_cmo_allocated_show,     NULL),
+	__ATTR(cmo_allocs_failed, S_IWUSR|S_IRUSR|S_IWGRP|S_IRGRP|S_IROTH,
+	       viodev_cmo_allocs_failed_show, viodev_cmo_allocs_failed_reset),
+	__ATTR_NULL
+};
+
+/* sysfs bus functions and data structures for CMO */
+
+#define viobus_cmo_rd_attr(name)                                        \
+static ssize_t cmo_##name##_show(struct bus_type *bt, char *buf)        \
+{                                                                       \
+	return sprintf(buf, "%lu\n", vio_cmo.name);                     \
+}                                                                       \
+static BUS_ATTR_RO(cmo_##name)
+
+#define viobus_cmo_pool_rd_attr(name, var)                              \
+static ssize_t                                                          \
+cmo_##name##_##var##_show(struct bus_type *bt, char *buf)               \
+{                                                                       \
+	return sprintf(buf, "%lu\n", vio_cmo.name.var);                 \
+}                                                                       \
+static BUS_ATTR_RO(cmo_##name##_##var)
+
+viobus_cmo_rd_attr(entitled);
+viobus_cmo_rd_attr(spare);
+viobus_cmo_rd_attr(min);
+viobus_cmo_rd_attr(desired);
+viobus_cmo_rd_attr(curr);
+viobus_cmo_pool_rd_attr(reserve, size);
+viobus_cmo_pool_rd_attr(excess, size);
+viobus_cmo_pool_rd_attr(excess, free);
+
+static ssize_t cmo_high_show(struct bus_type *bt, char *buf)
+{
+	return sprintf(buf, "%lu\n", vio_cmo.high);
+}
+
+static ssize_t cmo_high_store(struct bus_type *bt, const char *buf,
+			      size_t count)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&vio_cmo.lock, flags);
+	vio_cmo.high = vio_cmo.curr;
+	spin_unlock_irqrestore(&vio_cmo.lock, flags);
+
+	return count;
+}
+static BUS_ATTR_RW(cmo_high);
+
+static struct attribute *vio_bus_attrs[] = {
+	&bus_attr_cmo_entitled.attr,
+	&bus_attr_cmo_spare.attr,
+	&bus_attr_cmo_min.attr,
+	&bus_attr_cmo_desired.attr,
+	&bus_attr_cmo_curr.attr,
+	&bus_attr_cmo_high.attr,
+	&bus_attr_cmo_reserve_size.attr,
+	&bus_attr_cmo_excess_size.attr,
+	&bus_attr_cmo_excess_free.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(vio_bus);
+
+static void vio_cmo_sysfs_init(void)
+{
+	vio_bus_type.dev_attrs = vio_cmo_dev_attrs;
+	vio_bus_type.bus_groups = vio_bus_groups;
+}
+#else /* CONFIG_PPC_SMLPAR */
+int vio_cmo_entitlement_update(size_t new_entitlement) { return 0; }
+void vio_cmo_set_dev_desired(struct vio_dev *viodev, size_t desired) {}
+static int vio_cmo_bus_probe(struct vio_dev *viodev) { return 0; }
+static void vio_cmo_bus_remove(struct vio_dev *viodev) {}
+static void vio_cmo_set_dma_ops(struct vio_dev *viodev) {}
+static void vio_cmo_bus_init(void) {}
+static void vio_cmo_sysfs_init(void) { }
+#endif /* CONFIG_PPC_SMLPAR */
+EXPORT_SYMBOL(vio_cmo_entitlement_update);
+EXPORT_SYMBOL(vio_cmo_set_dev_desired);
+
+
+/*
+ * Platform Facilities Option (PFO) support
+ */
+
+/**
+ * vio_h_cop_sync - Perform a synchronous PFO co-processor operation
+ *
+ * @vdev - Pointer to a struct vio_dev for device
+ * @op - Pointer to a struct vio_pfo_op for the operation parameters
+ *
+ * Calls the hypervisor to synchronously perform the PFO operation
+ * described in @op.  In the case of a busy response from the hypervisor,
+ * the operation will be re-submitted indefinitely unless a non-zero timeout
+ * is specified or an error occurs. The timeout places a limit on when to
+ * stop re-submitting a operation, the total time can be exceeded if an
+ * operation is in progress.
+ *
+ * If op->hcall_ret is not NULL, this will be set to the return from the
+ * last h_cop_op call or it will be 0 if an error not involving the h_call
+ * was encountered.
+ *
+ * Returns:
+ *	0 on success,
+ *	-EINVAL if the h_call fails due to an invalid parameter,
+ *	-E2BIG if the h_call can not be performed synchronously,
+ *	-EBUSY if a timeout is specified and has elapsed,
+ *	-EACCES if the memory area for data/status has been rescinded, or
+ *	-EPERM if a hardware fault has been indicated
+ */
+int vio_h_cop_sync(struct vio_dev *vdev, struct vio_pfo_op *op)
+{
+	struct device *dev = &vdev->dev;
+	unsigned long deadline = 0;
+	long hret = 0;
+	int ret = 0;
+
+	if (op->timeout)
+		deadline = jiffies + msecs_to_jiffies(op->timeout);
+
+	while (true) {
+		hret = plpar_hcall_norets(H_COP, op->flags,
+				vdev->resource_id,
+				op->in, op->inlen, op->out,
+				op->outlen, op->csbcpb);
+
+		if (hret == H_SUCCESS ||
+		    (hret != H_NOT_ENOUGH_RESOURCES &&
+		     hret != H_BUSY && hret != H_RESOURCE) ||
+		    (op->timeout && time_after(deadline, jiffies)))
+			break;
+
+		dev_dbg(dev, "%s: hcall ret(%ld), retrying.\n", __func__, hret);
+	}
+
+	switch (hret) {
+	case H_SUCCESS:
+		ret = 0;
+		break;
+	case H_OP_MODE:
+	case H_TOO_BIG:
+		ret = -E2BIG;
+		break;
+	case H_RESCINDED:
+		ret = -EACCES;
+		break;
+	case H_HARDWARE:
+		ret = -EPERM;
+		break;
+	case H_NOT_ENOUGH_RESOURCES:
+	case H_RESOURCE:
+	case H_BUSY:
+		ret = -EBUSY;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	if (ret)
+		dev_dbg(dev, "%s: Sync h_cop_op failure (ret:%d) (hret:%ld)\n",
+				__func__, ret, hret);
+
+	op->hcall_err = hret;
+	return ret;
+}
+EXPORT_SYMBOL(vio_h_cop_sync);
+
+static struct iommu_table *vio_build_iommu_table(struct vio_dev *dev)
+{
+	const __be32 *dma_window;
+	struct iommu_table *tbl;
+	unsigned long offset, size;
+
+	dma_window = of_get_property(dev->dev.of_node,
+				  "ibm,my-dma-window", NULL);
+	if (!dma_window)
+		return NULL;
+
+	tbl = kzalloc(sizeof(*tbl), GFP_KERNEL);
+	if (tbl == NULL)
+		return NULL;
+
+	of_parse_dma_window(dev->dev.of_node, dma_window,
+			    &tbl->it_index, &offset, &size);
+
+	/* TCE table size - measured in tce entries */
+	tbl->it_page_shift = IOMMU_PAGE_SHIFT_4K;
+	tbl->it_size = size >> tbl->it_page_shift;
+	/* offset for VIO should always be 0 */
+	tbl->it_offset = offset >> tbl->it_page_shift;
+	tbl->it_busno = 0;
+	tbl->it_type = TCE_VB;
+	tbl->it_blocksize = 16;
+
+	if (firmware_has_feature(FW_FEATURE_LPAR))
+		tbl->it_ops = &iommu_table_lpar_multi_ops;
+	else
+		tbl->it_ops = &iommu_table_pseries_ops;
+
+	return iommu_init_table(tbl, -1);
+}
+
+/**
+ * vio_match_device: - Tell if a VIO device has a matching
+ *			VIO device id structure.
+ * @ids:	array of VIO device id structures to search in
+ * @dev:	the VIO device structure to match against
+ *
+ * Used by a driver to check whether a VIO device present in the
+ * system is in its list of supported devices. Returns the matching
+ * vio_device_id structure or NULL if there is no match.
+ */
+static const struct vio_device_id *vio_match_device(
+		const struct vio_device_id *ids, const struct vio_dev *dev)
+{
+	while (ids->type[0] != '\0') {
+		if ((strncmp(dev->type, ids->type, strlen(ids->type)) == 0) &&
+		    of_device_is_compatible(dev->dev.of_node,
+					 ids->compat))
+			return ids;
+		ids++;
+	}
+	return NULL;
+}
+
+/*
+ * Convert from struct device to struct vio_dev and pass to driver.
+ * dev->driver has already been set by generic code because vio_bus_match
+ * succeeded.
+ */
+static int vio_bus_probe(struct device *dev)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+	struct vio_driver *viodrv = to_vio_driver(dev->driver);
+	const struct vio_device_id *id;
+	int error = -ENODEV;
+
+	if (!viodrv->probe)
+		return error;
+
+	id = vio_match_device(viodrv->id_table, viodev);
+	if (id) {
+		memset(&viodev->cmo, 0, sizeof(viodev->cmo));
+		if (firmware_has_feature(FW_FEATURE_CMO)) {
+			error = vio_cmo_bus_probe(viodev);
+			if (error)
+				return error;
+		}
+		error = viodrv->probe(viodev, id);
+		if (error && firmware_has_feature(FW_FEATURE_CMO))
+			vio_cmo_bus_remove(viodev);
+	}
+
+	return error;
+}
+
+/* convert from struct device to struct vio_dev and pass to driver. */
+static int vio_bus_remove(struct device *dev)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+	struct vio_driver *viodrv = to_vio_driver(dev->driver);
+	struct device *devptr;
+	int ret = 1;
+
+	/*
+	 * Hold a reference to the device after the remove function is called
+	 * to allow for CMO accounting cleanup for the device.
+	 */
+	devptr = get_device(dev);
+
+	if (viodrv->remove)
+		ret = viodrv->remove(viodev);
+
+	if (!ret && firmware_has_feature(FW_FEATURE_CMO))
+		vio_cmo_bus_remove(viodev);
+
+	put_device(devptr);
+	return ret;
+}
+
+/**
+ * vio_register_driver: - Register a new vio driver
+ * @viodrv:	The vio_driver structure to be registered.
+ */
+int __vio_register_driver(struct vio_driver *viodrv, struct module *owner,
+			  const char *mod_name)
+{
+	pr_debug("%s: driver %s registering\n", __func__, viodrv->name);
+
+	/* fill in 'struct driver' fields */
+	viodrv->driver.name = viodrv->name;
+	viodrv->driver.pm = viodrv->pm;
+	viodrv->driver.bus = &vio_bus_type;
+	viodrv->driver.owner = owner;
+	viodrv->driver.mod_name = mod_name;
+
+	return driver_register(&viodrv->driver);
+}
+EXPORT_SYMBOL(__vio_register_driver);
+
+/**
+ * vio_unregister_driver - Remove registration of vio driver.
+ * @viodrv:	The vio_driver struct to be removed form registration
+ */
+void vio_unregister_driver(struct vio_driver *viodrv)
+{
+	driver_unregister(&viodrv->driver);
+}
+EXPORT_SYMBOL(vio_unregister_driver);
+
+/* vio_dev refcount hit 0 */
+static void vio_dev_release(struct device *dev)
+{
+	struct iommu_table *tbl = get_iommu_table_base(dev);
+
+	if (tbl)
+		iommu_free_table(tbl, of_node_full_name(dev->of_node));
+	of_node_put(dev->of_node);
+	kfree(to_vio_dev(dev));
+}
+
+/**
+ * vio_register_device_node: - Register a new vio device.
+ * @of_node:	The OF node for this device.
+ *
+ * Creates and initializes a vio_dev structure from the data in
+ * of_node and adds it to the list of virtual devices.
+ * Returns a pointer to the created vio_dev or NULL if node has
+ * NULL device_type or compatible fields.
+ */
+struct vio_dev *vio_register_device_node(struct device_node *of_node)
+{
+	struct vio_dev *viodev;
+	struct device_node *parent_node;
+	const __be32 *prop;
+	enum vio_dev_family family;
+	const char *of_node_name = of_node->name ? of_node->name : "<unknown>";
+
+	/*
+	 * Determine if this node is a under the /vdevice node or under the
+	 * /ibm,platform-facilities node.  This decides the device's family.
+	 */
+	parent_node = of_get_parent(of_node);
+	if (parent_node) {
+		if (!strcmp(parent_node->full_name, "/ibm,platform-facilities"))
+			family = PFO;
+		else if (!strcmp(parent_node->full_name, "/vdevice"))
+			family = VDEVICE;
+		else {
+			pr_warn("%s: parent(%s) of %s not recognized.\n",
+					__func__,
+					parent_node->full_name,
+					of_node_name);
+			of_node_put(parent_node);
+			return NULL;
+		}
+		of_node_put(parent_node);
+	} else {
+		pr_warn("%s: could not determine the parent of node %s.\n",
+				__func__, of_node_name);
+		return NULL;
+	}
+
+	if (family == PFO) {
+		if (of_get_property(of_node, "interrupt-controller", NULL)) {
+			pr_debug("%s: Skipping the interrupt controller %s.\n",
+					__func__, of_node_name);
+			return NULL;
+		}
+	}
+
+	/* allocate a vio_dev for this node */
+	viodev = kzalloc(sizeof(struct vio_dev), GFP_KERNEL);
+	if (viodev == NULL) {
+		pr_warn("%s: allocation failure for VIO device.\n", __func__);
+		return NULL;
+	}
+
+	/* we need the 'device_type' property, in order to match with drivers */
+	viodev->family = family;
+	if (viodev->family == VDEVICE) {
+		unsigned int unit_address;
+
+		if (of_node->type != NULL)
+			viodev->type = of_node->type;
+		else {
+			pr_warn("%s: node %s is missing the 'device_type' "
+					"property.\n", __func__, of_node_name);
+			goto out;
+		}
+
+		prop = of_get_property(of_node, "reg", NULL);
+		if (prop == NULL) {
+			pr_warn("%s: node %s missing 'reg'\n",
+					__func__, of_node_name);
+			goto out;
+		}
+		unit_address = of_read_number(prop, 1);
+		dev_set_name(&viodev->dev, "%x", unit_address);
+		viodev->irq = irq_of_parse_and_map(of_node, 0);
+		viodev->unit_address = unit_address;
+	} else {
+		/* PFO devices need their resource_id for submitting COP_OPs
+		 * This is an optional field for devices, but is required when
+		 * performing synchronous ops */
+		prop = of_get_property(of_node, "ibm,resource-id", NULL);
+		if (prop != NULL)
+			viodev->resource_id = of_read_number(prop, 1);
+
+		dev_set_name(&viodev->dev, "%s", of_node_name);
+		viodev->type = of_node_name;
+		viodev->irq = 0;
+	}
+
+	viodev->name = of_node->name;
+	viodev->dev.of_node = of_node_get(of_node);
+
+	set_dev_node(&viodev->dev, of_node_to_nid(of_node));
+
+	/* init generic 'struct device' fields: */
+	viodev->dev.parent = &vio_bus_device.dev;
+	viodev->dev.bus = &vio_bus_type;
+	viodev->dev.release = vio_dev_release;
+
+	if (of_get_property(viodev->dev.of_node, "ibm,my-dma-window", NULL)) {
+		if (firmware_has_feature(FW_FEATURE_CMO))
+			vio_cmo_set_dma_ops(viodev);
+		else
+			set_dma_ops(&viodev->dev, &dma_iommu_ops);
+
+		set_iommu_table_base(&viodev->dev,
+				     vio_build_iommu_table(viodev));
+
+		/* needed to ensure proper operation of coherent allocations
+		 * later, in case driver doesn't set it explicitly */
+		viodev->dev.coherent_dma_mask = DMA_BIT_MASK(64);
+		viodev->dev.dma_mask = &viodev->dev.coherent_dma_mask;
+	}
+
+	/* register with generic device framework */
+	if (device_register(&viodev->dev)) {
+		printk(KERN_ERR "%s: failed to register device %s\n",
+				__func__, dev_name(&viodev->dev));
+		put_device(&viodev->dev);
+		return NULL;
+	}
+
+	return viodev;
+
+out:	/* Use this exit point for any return prior to device_register */
+	kfree(viodev);
+
+	return NULL;
+}
+EXPORT_SYMBOL(vio_register_device_node);
+
+/*
+ * vio_bus_scan_for_devices - Scan OF and register each child device
+ * @root_name - OF node name for the root of the subtree to search.
+ *		This must be non-NULL
+ *
+ * Starting from the root node provide, register the device node for
+ * each child beneath the root.
+ */
+static void vio_bus_scan_register_devices(char *root_name)
+{
+	struct device_node *node_root, *node_child;
+
+	if (!root_name)
+		return;
+
+	node_root = of_find_node_by_name(NULL, root_name);
+	if (node_root) {
+
+		/*
+		 * Create struct vio_devices for each virtual device in
+		 * the device tree. Drivers will associate with them later.
+		 */
+		node_child = of_get_next_child(node_root, NULL);
+		while (node_child) {
+			vio_register_device_node(node_child);
+			node_child = of_get_next_child(node_root, node_child);
+		}
+		of_node_put(node_root);
+	}
+}
+
+/**
+ * vio_bus_init: - Initialize the virtual IO bus
+ */
+static int __init vio_bus_init(void)
+{
+	int err;
+
+	if (firmware_has_feature(FW_FEATURE_CMO))
+		vio_cmo_sysfs_init();
+
+	err = bus_register(&vio_bus_type);
+	if (err) {
+		printk(KERN_ERR "failed to register VIO bus\n");
+		return err;
+	}
+
+	/*
+	 * The fake parent of all vio devices, just to give us
+	 * a nice directory
+	 */
+	err = device_register(&vio_bus_device.dev);
+	if (err) {
+		printk(KERN_WARNING "%s: device_register returned %i\n",
+				__func__, err);
+		return err;
+	}
+
+	if (firmware_has_feature(FW_FEATURE_CMO))
+		vio_cmo_bus_init();
+
+	return 0;
+}
+postcore_initcall(vio_bus_init);
+
+static int __init vio_device_init(void)
+{
+	vio_bus_scan_register_devices("vdevice");
+	vio_bus_scan_register_devices("ibm,platform-facilities");
+
+	return 0;
+}
+device_initcall(vio_device_init);
+
+static ssize_t name_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%s\n", to_vio_dev(dev)->name);
+}
+
+static ssize_t devspec_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct device_node *of_node = dev->of_node;
+
+	return sprintf(buf, "%s\n", of_node_full_name(of_node));
+}
+
+static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	const struct vio_dev *vio_dev = to_vio_dev(dev);
+	struct device_node *dn;
+	const char *cp;
+
+	dn = dev->of_node;
+	if (!dn) {
+		strcpy(buf, "\n");
+		return strlen(buf);
+	}
+	cp = of_get_property(dn, "compatible", NULL);
+	if (!cp) {
+		strcpy(buf, "\n");
+		return strlen(buf);
+	}
+
+	return sprintf(buf, "vio:T%sS%s\n", vio_dev->type, cp);
+}
+
+static struct device_attribute vio_dev_attrs[] = {
+	__ATTR_RO(name),
+	__ATTR_RO(devspec),
+	__ATTR_RO(modalias),
+	__ATTR_NULL
+};
+
+void vio_unregister_device(struct vio_dev *viodev)
+{
+	device_unregister(&viodev->dev);
+}
+EXPORT_SYMBOL(vio_unregister_device);
+
+static int vio_bus_match(struct device *dev, struct device_driver *drv)
+{
+	const struct vio_dev *vio_dev = to_vio_dev(dev);
+	struct vio_driver *vio_drv = to_vio_driver(drv);
+	const struct vio_device_id *ids = vio_drv->id_table;
+
+	return (ids != NULL) && (vio_match_device(ids, vio_dev) != NULL);
+}
+
+static int vio_hotplug(struct device *dev, struct kobj_uevent_env *env)
+{
+	const struct vio_dev *vio_dev = to_vio_dev(dev);
+	struct device_node *dn;
+	const char *cp;
+
+	dn = dev->of_node;
+	if (!dn)
+		return -ENODEV;
+	cp = of_get_property(dn, "compatible", NULL);
+	if (!cp)
+		return -ENODEV;
+
+	add_uevent_var(env, "MODALIAS=vio:T%sS%s", vio_dev->type, cp);
+	return 0;
+}
+
+struct bus_type vio_bus_type = {
+	.name = "vio",
+	.dev_attrs = vio_dev_attrs,
+	.uevent = vio_hotplug,
+	.match = vio_bus_match,
+	.probe = vio_bus_probe,
+	.remove = vio_bus_remove,
+};
+
+/**
+ * vio_get_attribute: - get attribute for virtual device
+ * @vdev:	The vio device to get property.
+ * @which:	The property/attribute to be extracted.
+ * @length:	Pointer to length of returned data size (unused if NULL).
+ *
+ * Calls prom.c's of_get_property() to return the value of the
+ * attribute specified by @which
+*/
+const void *vio_get_attribute(struct vio_dev *vdev, char *which, int *length)
+{
+	return of_get_property(vdev->dev.of_node, which, length);
+}
+EXPORT_SYMBOL(vio_get_attribute);
+
+#ifdef CONFIG_PPC_PSERIES
+/* vio_find_name() - internal because only vio.c knows how we formatted the
+ * kobject name
+ */
+static struct vio_dev *vio_find_name(const char *name)
+{
+	struct device *found;
+
+	found = bus_find_device_by_name(&vio_bus_type, NULL, name);
+	if (!found)
+		return NULL;
+
+	return to_vio_dev(found);
+}
+
+/**
+ * vio_find_node - find an already-registered vio_dev
+ * @vnode: device_node of the virtual device we're looking for
+ *
+ * Takes a reference to the embedded struct device which needs to be dropped
+ * after use.
+ */
+struct vio_dev *vio_find_node(struct device_node *vnode)
+{
+	char kobj_name[20];
+	struct device_node *vnode_parent;
+	const char *dev_type;
+
+	vnode_parent = of_get_parent(vnode);
+	if (!vnode_parent)
+		return NULL;
+
+	dev_type = of_get_property(vnode_parent, "device_type", NULL);
+	of_node_put(vnode_parent);
+	if (!dev_type)
+		return NULL;
+
+	/* construct the kobject name from the device node */
+	if (!strcmp(dev_type, "vdevice")) {
+		const __be32 *prop;
+		
+		prop = of_get_property(vnode, "reg", NULL);
+		if (!prop)
+			return NULL;
+		snprintf(kobj_name, sizeof(kobj_name), "%x",
+			 (uint32_t)of_read_number(prop, 1));
+	} else if (!strcmp(dev_type, "ibm,platform-facilities"))
+		snprintf(kobj_name, sizeof(kobj_name), "%s", vnode->name);
+	else
+		return NULL;
+
+	return vio_find_name(kobj_name);
+}
+EXPORT_SYMBOL(vio_find_node);
+
+int vio_enable_interrupts(struct vio_dev *dev)
+{
+	int rc = h_vio_signal(dev->unit_address, VIO_IRQ_ENABLE);
+	if (rc != H_SUCCESS)
+		printk(KERN_ERR "vio: Error 0x%x enabling interrupts\n", rc);
+	return rc;
+}
+EXPORT_SYMBOL(vio_enable_interrupts);
+
+int vio_disable_interrupts(struct vio_dev *dev)
+{
+	int rc = h_vio_signal(dev->unit_address, VIO_IRQ_DISABLE);
+	if (rc != H_SUCCESS)
+		printk(KERN_ERR "vio: Error 0x%x disabling interrupts\n", rc);
+	return rc;
+}
+EXPORT_SYMBOL(vio_disable_interrupts);
+#endif /* CONFIG_PPC_PSERIES */