Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney...
[sfrench/cifs-2.6.git] / arch / powerpc / kernel / vio.c
index f0bad7070fb54087d241f6a81bf9ea875f71156b..ade8aeaa2e706b496755d65a856f73f4d3bc67b8 100644 (file)
@@ -1,11 +1,12 @@
 /*
  * IBM PowerPC Virtual I/O Infrastructure Support.
  *
- *    Copyright (c) 2003-2005 IBM Corp.
+ *    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
@@ -46,6 +47,996 @@ static struct vio_dev vio_bus_device  = { /* fake "parent" device */
        .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
+ */
+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 = min(spare_needed, min(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(container_of(work, struct 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)
+{
+       struct vio_dev *viodev = to_vio_dev(dev);
+       void *ret;
+
+       if (vio_cmo_alloc(viodev, roundup(size, IOMMU_PAGE_SIZE))) {
+               atomic_inc(&viodev->cmo.allocs_failed);
+               return NULL;
+       }
+
+       ret = dma_iommu_ops.alloc_coherent(dev, size, dma_handle, flag);
+       if (unlikely(ret == NULL)) {
+               vio_cmo_dealloc(viodev, roundup(size, IOMMU_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)
+{
+       struct vio_dev *viodev = to_vio_dev(dev);
+
+       dma_iommu_ops.free_coherent(dev, size, vaddr, dma_handle);
+
+       vio_cmo_dealloc(viodev, roundup(size, IOMMU_PAGE_SIZE));
+}
+
+static dma_addr_t vio_dma_iommu_map_single(struct device *dev, void *vaddr,
+                                           size_t size,
+                                           enum dma_data_direction direction,
+                                           struct dma_attrs *attrs)
+{
+       struct vio_dev *viodev = to_vio_dev(dev);
+       dma_addr_t ret = DMA_ERROR_CODE;
+
+       if (vio_cmo_alloc(viodev, roundup(size, IOMMU_PAGE_SIZE))) {
+               atomic_inc(&viodev->cmo.allocs_failed);
+               return ret;
+       }
+
+       ret = dma_iommu_ops.map_single(dev, vaddr, size, direction, attrs);
+       if (unlikely(dma_mapping_error(ret))) {
+               vio_cmo_dealloc(viodev, roundup(size, IOMMU_PAGE_SIZE));
+               atomic_inc(&viodev->cmo.allocs_failed);
+       }
+
+       return ret;
+}
+
+static void vio_dma_iommu_unmap_single(struct device *dev,
+               dma_addr_t dma_handle, size_t size,
+               enum dma_data_direction direction,
+               struct dma_attrs *attrs)
+{
+       struct vio_dev *viodev = to_vio_dev(dev);
+
+       dma_iommu_ops.unmap_single(dev, dma_handle, size, direction, attrs);
+
+       vio_cmo_dealloc(viodev, roundup(size, IOMMU_PAGE_SIZE));
+}
+
+static int vio_dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
+                                int nelems, enum dma_data_direction direction,
+                                struct dma_attrs *attrs)
+{
+       struct vio_dev *viodev = to_vio_dev(dev);
+       struct scatterlist *sgl;
+       int ret, count = 0;
+       size_t alloc_size = 0;
+
+       for (sgl = sglist; count < nelems; count++, sgl++)
+               alloc_size += roundup(sgl->length, IOMMU_PAGE_SIZE);
+
+       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);
+       }
+
+       for (sgl = sglist, count = 0; count < ret; count++, sgl++)
+               alloc_size -= roundup(sgl->dma_length, IOMMU_PAGE_SIZE);
+       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,
+               struct dma_attrs *attrs)
+{
+       struct vio_dev *viodev = to_vio_dev(dev);
+       struct scatterlist *sgl;
+       size_t alloc_size = 0;
+       int count = 0;
+
+       for (sgl = sglist; count < nelems; count++, sgl++)
+               alloc_size += roundup(sgl->dma_length, IOMMU_PAGE_SIZE);
+
+       dma_iommu_ops.unmap_sg(dev, sglist, nelems, direction, attrs);
+
+       vio_cmo_dealloc(viodev, alloc_size);
+}
+
+struct dma_mapping_ops vio_dma_mapping_ops = {
+       .alloc_coherent = vio_dma_iommu_alloc_coherent,
+       .free_coherent  = vio_dma_iommu_free_coherent,
+       .map_single     = vio_dma_iommu_map_single,
+       .unmap_single   = vio_dma_iommu_unmap_single,
+       .map_sg         = vio_dma_iommu_map_sg,
+       .unmap_sg       = vio_dma_iommu_unmap_sg,
+};
+
+/**
+ * vio_cmo_set_dev_desired - Set desired entitlement for a device
+ *
+ * @viodev: struct vio_dev for device to alter
+ * @new_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)
+               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 vio_driver *viodrv = to_vio_driver(dev->driver);
+       unsigned long flags;
+       size_t size;
+
+       /*
+        * Check to see that device has a DMA window and configure
+        * entitlement for the device.
+        */
+       if (of_get_property(viodev->dev.archdata.of_node,
+                           "ibm,my-dma-window", NULL)) {
+               /* 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));
+               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)
+{
+       vio_dma_mapping_ops.dma_supported = dma_iommu_ops.dma_supported;
+       viodev->dev.archdata.dma_ops = &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 = strict_strtoul(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 struct device_attribute vio_cmo_dev_attrs[] = {
+       __ATTR_RO(name),
+       __ATTR_RO(devspec),
+       __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                                                          \
+viobus_cmo_##name##_show(struct bus_type *bt, char *buf)                \
+{                                                                       \
+       return sprintf(buf, "%lu\n", vio_cmo.name);                     \
+}
+
+#define viobus_cmo_pool_rd_attr(name, var)                              \
+static ssize_t                                                          \
+viobus_cmo_##name##_pool_show_##var(struct bus_type *bt, char *buf)     \
+{                                                                       \
+       return sprintf(buf, "%lu\n", vio_cmo.name.var);                 \
+}
+
+static ssize_t viobus_cmo_high_reset(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;
+}
+
+viobus_cmo_rd_attr(entitled);
+viobus_cmo_pool_rd_attr(reserve, size);
+viobus_cmo_pool_rd_attr(excess, size);
+viobus_cmo_pool_rd_attr(excess, free);
+viobus_cmo_rd_attr(spare);
+viobus_cmo_rd_attr(min);
+viobus_cmo_rd_attr(desired);
+viobus_cmo_rd_attr(curr);
+viobus_cmo_rd_attr(high);
+
+static struct bus_attribute vio_cmo_bus_attrs[] = {
+       __ATTR(cmo_entitled, S_IRUGO, viobus_cmo_entitled_show, NULL),
+       __ATTR(cmo_reserve_size, S_IRUGO, viobus_cmo_reserve_pool_show_size, NULL),
+       __ATTR(cmo_excess_size, S_IRUGO, viobus_cmo_excess_pool_show_size, NULL),
+       __ATTR(cmo_excess_free, S_IRUGO, viobus_cmo_excess_pool_show_free, NULL),
+       __ATTR(cmo_spare,   S_IRUGO, viobus_cmo_spare_show,   NULL),
+       __ATTR(cmo_min,     S_IRUGO, viobus_cmo_min_show,     NULL),
+       __ATTR(cmo_desired, S_IRUGO, viobus_cmo_desired_show, NULL),
+       __ATTR(cmo_curr,    S_IRUGO, viobus_cmo_curr_show,    NULL),
+       __ATTR(cmo_high,    S_IWUSR|S_IRUSR|S_IWGRP|S_IRGRP|S_IROTH,
+              viobus_cmo_high_show, viobus_cmo_high_reset),
+       __ATTR_NULL
+};
+
+static void vio_cmo_sysfs_init(void)
+{
+       vio_bus_type.dev_attrs = vio_cmo_dev_attrs;
+       vio_bus_type.bus_attrs = vio_cmo_bus_attrs;
+}
+#else /* CONFIG_PPC_SMLPAR */
+/* Dummy functions for iSeries platform */
+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() {}
+static void vio_cmo_sysfs_init() { }
+#endif /* CONFIG_PPC_SMLPAR */
+EXPORT_SYMBOL(vio_cmo_entitlement_update);
+EXPORT_SYMBOL(vio_cmo_set_dev_desired);
+
 static struct iommu_table *vio_build_iommu_table(struct vio_dev *dev)
 {
        const unsigned char *dma_window;
@@ -114,8 +1105,17 @@ static int vio_bus_probe(struct device *dev)
                return error;
 
        id = vio_match_device(viodrv->id_table, viodev);
-       if (id)
+       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)
+                       vio_cmo_bus_remove(viodev);
+       }
 
        return error;
 }
@@ -125,12 +1125,23 @@ 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)
-               return viodrv->remove(viodev);
+               ret = viodrv->remove(viodev);
+
+       if (!ret && firmware_has_feature(FW_FEATURE_CMO))
+               vio_cmo_bus_remove(viodev);
 
-       /* driver can't remove */
-       return 1;
+       put_device(devptr);
+       return ret;
 }
 
 /**
@@ -139,7 +1150,7 @@ static int vio_bus_remove(struct device *dev)
  */
 int vio_register_driver(struct vio_driver *viodrv)
 {
-       printk(KERN_DEBUG "%s: driver %s registering\n", __FUNCTION__,
+       printk(KERN_DEBUG "%s: driver %s registering\n", __func__,
                viodrv->driver.name);
 
        /* fill in 'struct driver' fields */
@@ -176,7 +1187,7 @@ static void __devinit vio_dev_release(struct device *dev)
  * Returns a pointer to the created vio_dev or NULL if node has
  * NULL device_type or compatible fields.
  */
-struct vio_dev * __devinit vio_register_device_node(struct device_node *of_node)
+struct vio_dev *vio_register_device_node(struct device_node *of_node)
 {
        struct vio_dev *viodev;
        const unsigned int *unit_address;
@@ -184,7 +1195,7 @@ struct vio_dev * __devinit vio_register_device_node(struct device_node *of_node)
        /* we need the 'device_type' property, in order to match with drivers */
        if (of_node->type == NULL) {
                printk(KERN_WARNING "%s: node %s missing 'device_type'\n",
-                               __FUNCTION__,
+                               __func__,
                                of_node->name ? of_node->name : "<unknown>");
                return NULL;
        }
@@ -192,7 +1203,7 @@ struct vio_dev * __devinit vio_register_device_node(struct device_node *of_node)
        unit_address = of_get_property(of_node, "reg", NULL);
        if (unit_address == NULL) {
                printk(KERN_WARNING "%s: node %s missing 'reg'\n",
-                               __FUNCTION__,
+                               __func__,
                                of_node->name ? of_node->name : "<unknown>");
                return NULL;
        }
@@ -215,7 +1226,11 @@ struct vio_dev * __devinit vio_register_device_node(struct device_node *of_node)
                        viodev->unit_address = *unit_address;
        }
        viodev->dev.archdata.of_node = of_node_get(of_node);
-       viodev->dev.archdata.dma_ops = &dma_iommu_ops;
+
+       if (firmware_has_feature(FW_FEATURE_CMO))
+               vio_cmo_set_dma_ops(viodev);
+       else
+               viodev->dev.archdata.dma_ops = &dma_iommu_ops;
        viodev->dev.archdata.dma_data = vio_build_iommu_table(viodev);
        viodev->dev.archdata.numa_node = of_node_to_nid(of_node);
 
@@ -227,7 +1242,7 @@ struct vio_dev * __devinit vio_register_device_node(struct device_node *of_node)
        /* register with generic device framework */
        if (device_register(&viodev->dev)) {
                printk(KERN_ERR "%s: failed to register device %s\n",
-                               __FUNCTION__, viodev->dev.bus_id);
+                               __func__, viodev->dev.bus_id);
                /* XXX free TCE table */
                kfree(viodev);
                return NULL;
@@ -245,6 +1260,9 @@ static int __init vio_bus_init(void)
        int err;
        struct device_node *node_vroot;
 
+       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");
@@ -258,10 +1276,13 @@ static int __init vio_bus_init(void)
        err = device_register(&vio_bus_device.dev);
        if (err) {
                printk(KERN_WARNING "%s: device_register returned %i\n",
-                               __FUNCTION__, err);
+                               __func__, err);
                return err;
        }
 
+       if (firmware_has_feature(FW_FEATURE_CMO))
+               vio_cmo_bus_init();
+
        node_vroot = of_find_node_by_name(NULL, "vdevice");
        if (node_vroot) {
                struct device_node *of_node;