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Release 4.14 arch/powerpc/platforms/pseries/vio.c

Directory: arch/powerpc/platforms/pseries
/*
 * 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;
}


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/**
 * 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;
}


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/**
 * 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);
}


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Hagen Paul Pfeifer10.31%150.00%


Total327100.00%2100.00%



/**
 * 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;
}


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/**
 * 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);
}


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Jean Delvare10.21%150.00%


Total478100.00%2100.00%






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;
}


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Robert Jennings11594.26%250.00%


Andrzej Pietrasiewicz54.10%125.00%


Krzysztof Kozlowski21.64%125.00%


Total122100.00%4100.00%






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));
}


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Robert Jennings5588.71%250.00%


Andrzej Pietrasiewicz58.06%125.00%


Krzysztof Kozlowski23.23%125.00%


Total62100.00%4100.00%






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 = IOMMU_MAPPING_ERROR;

	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;
}


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Robert Jennings11475.50%116.67%


Alistair Popple2013.25%116.67%


Mark Nelson127.95%116.67%


Krzysztof Kozlowski21.32%116.67%


Stephen Rothwell21.32%116.67%


Christoph Hellwig10.66%116.67%


Total151100.00%6100.00%






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)));
}


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Robert Jennings5774.03%125.00%


Alistair Popple1620.78%125.00%


Krzysztof Kozlowski22.60%125.00%


Mark Nelson22.60%125.00%


Total77100.00%4100.00%






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;
}


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Robert Jennings15578.68%240.00%


Akinobu Mita2010.15%120.00%


Alistair Popple2010.15%120.00%


Krzysztof Kozlowski21.02%120.00%


Total197100.00%5100.00%






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);
}


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Robert Jennings8074.07%125.00%


Alistair Popple1614.81%125.00%


Akinobu Mita109.26%125.00%


Krzysztof Kozlowski21.85%125.00%


Total108100.00%4100.00%






static int vio_dma_iommu_dma_supported(struct device *dev, u64 mask)
{
        return dma_iommu_ops.dma_supported(dev, mask);
}


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Total24100.00%1100.00%






static u64 vio_dma_get_required_mask(struct device *dev)
{
        return dma_iommu_ops.get_required_mask(dev);
}


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Milton D. Miller II19100.00%1100.00%


Total19100.00%1100.00%




static const 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,
	.mapping_error	   = dma_iommu_mapping_error,
};

/**
 * 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);
}


Contributors
PersonTokensPropCommitsCommitProp
Robert Jennings25195.44%150.00%


Julia Lawall124.56%150.00%


Total263100.00%2100.00%



/**
 * 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