276 lines
6.2 KiB
C
276 lines
6.2 KiB
C
/*
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* Copyright(c) 2007 Intel Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 59
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* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* The full GNU General Public License is included in this distribution in the
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* file called COPYING.
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*/
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/*
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* This driver supports an interface for DCA clients and providers to meet.
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*/
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#include <linux/kernel.h>
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#include <linux/notifier.h>
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#include <linux/device.h>
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#include <linux/dca.h>
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#define DCA_VERSION "1.4"
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MODULE_VERSION(DCA_VERSION);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Intel Corporation");
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static DEFINE_SPINLOCK(dca_lock);
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static LIST_HEAD(dca_providers);
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static struct dca_provider *dca_find_provider_by_dev(struct device *dev)
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{
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struct dca_provider *dca, *ret = NULL;
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list_for_each_entry(dca, &dca_providers, node) {
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if ((!dev) || (dca->ops->dev_managed(dca, dev))) {
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ret = dca;
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break;
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}
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}
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return ret;
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}
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/**
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* dca_add_requester - add a dca client to the list
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* @dev - the device that wants dca service
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*/
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int dca_add_requester(struct device *dev)
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{
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struct dca_provider *dca;
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int err, slot = -ENODEV;
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if (!dev)
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return -EFAULT;
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spin_lock(&dca_lock);
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/* check if the requester has not been added already */
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dca = dca_find_provider_by_dev(dev);
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if (dca) {
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spin_unlock(&dca_lock);
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return -EEXIST;
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}
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list_for_each_entry(dca, &dca_providers, node) {
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slot = dca->ops->add_requester(dca, dev);
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if (slot >= 0)
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break;
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}
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if (slot < 0) {
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spin_unlock(&dca_lock);
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return slot;
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}
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err = dca_sysfs_add_req(dca, dev, slot);
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if (err) {
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dca->ops->remove_requester(dca, dev);
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spin_unlock(&dca_lock);
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return err;
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}
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spin_unlock(&dca_lock);
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return 0;
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}
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EXPORT_SYMBOL_GPL(dca_add_requester);
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/**
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* dca_remove_requester - remove a dca client from the list
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* @dev - the device that wants dca service
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*/
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int dca_remove_requester(struct device *dev)
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{
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struct dca_provider *dca;
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int slot;
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if (!dev)
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return -EFAULT;
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spin_lock(&dca_lock);
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dca = dca_find_provider_by_dev(dev);
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if (!dca) {
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spin_unlock(&dca_lock);
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return -ENODEV;
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}
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slot = dca->ops->remove_requester(dca, dev);
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if (slot < 0) {
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spin_unlock(&dca_lock);
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return slot;
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}
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dca_sysfs_remove_req(dca, slot);
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spin_unlock(&dca_lock);
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return 0;
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}
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EXPORT_SYMBOL_GPL(dca_remove_requester);
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/**
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* dca_common_get_tag - return the dca tag (serves both new and old api)
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* @dev - the device that wants dca service
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* @cpu - the cpuid as returned by get_cpu()
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*/
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u8 dca_common_get_tag(struct device *dev, int cpu)
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{
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struct dca_provider *dca;
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u8 tag;
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spin_lock(&dca_lock);
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dca = dca_find_provider_by_dev(dev);
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if (!dca) {
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spin_unlock(&dca_lock);
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return -ENODEV;
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}
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tag = dca->ops->get_tag(dca, dev, cpu);
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spin_unlock(&dca_lock);
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return tag;
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}
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/**
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* dca3_get_tag - return the dca tag to the requester device
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* for the given cpu (new api)
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* @dev - the device that wants dca service
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* @cpu - the cpuid as returned by get_cpu()
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*/
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u8 dca3_get_tag(struct device *dev, int cpu)
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{
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if (!dev)
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return -EFAULT;
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return dca_common_get_tag(dev, cpu);
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}
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EXPORT_SYMBOL_GPL(dca3_get_tag);
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/**
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* dca_get_tag - return the dca tag for the given cpu (old api)
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* @cpu - the cpuid as returned by get_cpu()
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*/
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u8 dca_get_tag(int cpu)
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{
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struct device *dev = NULL;
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return dca_common_get_tag(dev, cpu);
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}
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EXPORT_SYMBOL_GPL(dca_get_tag);
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/**
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* alloc_dca_provider - get data struct for describing a dca provider
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* @ops - pointer to struct of dca operation function pointers
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* @priv_size - size of extra mem to be added for provider's needs
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*/
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struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size)
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{
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struct dca_provider *dca;
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int alloc_size;
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alloc_size = (sizeof(*dca) + priv_size);
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dca = kzalloc(alloc_size, GFP_KERNEL);
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if (!dca)
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return NULL;
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dca->ops = ops;
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return dca;
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}
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EXPORT_SYMBOL_GPL(alloc_dca_provider);
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/**
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* free_dca_provider - release the dca provider data struct
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* @ops - pointer to struct of dca operation function pointers
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* @priv_size - size of extra mem to be added for provider's needs
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*/
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void free_dca_provider(struct dca_provider *dca)
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{
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kfree(dca);
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}
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EXPORT_SYMBOL_GPL(free_dca_provider);
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static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);
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/**
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* register_dca_provider - register a dca provider
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* @dca - struct created by alloc_dca_provider()
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* @dev - device providing dca services
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*/
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int register_dca_provider(struct dca_provider *dca, struct device *dev)
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{
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int err;
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err = dca_sysfs_add_provider(dca, dev);
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if (err)
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return err;
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list_add(&dca->node, &dca_providers);
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blocking_notifier_call_chain(&dca_provider_chain,
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DCA_PROVIDER_ADD, NULL);
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return 0;
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}
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EXPORT_SYMBOL_GPL(register_dca_provider);
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/**
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* unregister_dca_provider - remove a dca provider
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* @dca - struct created by alloc_dca_provider()
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*/
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void unregister_dca_provider(struct dca_provider *dca)
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{
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blocking_notifier_call_chain(&dca_provider_chain,
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DCA_PROVIDER_REMOVE, NULL);
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list_del(&dca->node);
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dca_sysfs_remove_provider(dca);
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}
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EXPORT_SYMBOL_GPL(unregister_dca_provider);
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/**
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* dca_register_notify - register a client's notifier callback
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*/
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void dca_register_notify(struct notifier_block *nb)
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{
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blocking_notifier_chain_register(&dca_provider_chain, nb);
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}
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EXPORT_SYMBOL_GPL(dca_register_notify);
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/**
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* dca_unregister_notify - remove a client's notifier callback
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*/
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void dca_unregister_notify(struct notifier_block *nb)
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{
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blocking_notifier_chain_unregister(&dca_provider_chain, nb);
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}
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EXPORT_SYMBOL_GPL(dca_unregister_notify);
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static int __init dca_init(void)
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{
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printk(KERN_ERR "dca service started, version %s\n", DCA_VERSION);
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return dca_sysfs_init();
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}
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static void __exit dca_exit(void)
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{
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dca_sysfs_exit();
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}
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module_init(dca_init);
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module_exit(dca_exit);
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