/* * Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved. * * 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. * * This program is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. * * You should have received a copy of the GNU General Public License along with * this program; if not, write to the Free Software Foundation, Inc., 59 * Temple Place - Suite 330, Boston, MA 02111-1307, USA. * * The full GNU General Public License is included in this distribution in the * file called COPYING. */ /* * This driver supports an interface for DCA clients and providers to meet. */ #include <linux/kernel.h> #include <linux/notifier.h> #include <linux/device.h> #include <linux/dca.h> #define DCA_VERSION "1.8" MODULE_VERSION(DCA_VERSION); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Intel Corporation"); static DEFINE_SPINLOCK(dca_lock); static LIST_HEAD(dca_providers); static struct dca_provider *dca_find_provider_by_dev(struct device *dev) { struct dca_provider *dca, *ret = NULL; list_for_each_entry(dca, &dca_providers, node) { if ((!dev) || (dca->ops->dev_managed(dca, dev))) { ret = dca; break; } } return ret; } /** * dca_add_requester - add a dca client to the list * @dev - the device that wants dca service */ int dca_add_requester(struct device *dev) { struct dca_provider *dca; int err, slot = -ENODEV; unsigned long flags; if (!dev) return -EFAULT; spin_lock_irqsave(&dca_lock, flags); /* check if the requester has not been added already */ dca = dca_find_provider_by_dev(dev); if (dca) { spin_unlock_irqrestore(&dca_lock, flags); return -EEXIST; } list_for_each_entry(dca, &dca_providers, node) { slot = dca->ops->add_requester(dca, dev); if (slot >= 0) break; } spin_unlock_irqrestore(&dca_lock, flags); if (slot < 0) return slot; err = dca_sysfs_add_req(dca, dev, slot); if (err) { spin_lock_irqsave(&dca_lock, flags); if (dca == dca_find_provider_by_dev(dev)) dca->ops->remove_requester(dca, dev); spin_unlock_irqrestore(&dca_lock, flags); return err; } return 0; } EXPORT_SYMBOL_GPL(dca_add_requester); /** * dca_remove_requester - remove a dca client from the list * @dev - the device that wants dca service */ int dca_remove_requester(struct device *dev) { struct dca_provider *dca; int slot; unsigned long flags; if (!dev) return -EFAULT; spin_lock_irqsave(&dca_lock, flags); dca = dca_find_provider_by_dev(dev); if (!dca) { spin_unlock_irqrestore(&dca_lock, flags); return -ENODEV; } slot = dca->ops->remove_requester(dca, dev); spin_unlock_irqrestore(&dca_lock, flags); if (slot < 0) return slot; dca_sysfs_remove_req(dca, slot); return 0; } EXPORT_SYMBOL_GPL(dca_remove_requester); /** * dca_common_get_tag - return the dca tag (serves both new and old api) * @dev - the device that wants dca service * @cpu - the cpuid as returned by get_cpu() */ u8 dca_common_get_tag(struct device *dev, int cpu) { struct dca_provider *dca; u8 tag; unsigned long flags; spin_lock_irqsave(&dca_lock, flags); dca = dca_find_provider_by_dev(dev); if (!dca) { spin_unlock_irqrestore(&dca_lock, flags); return -ENODEV; } tag = dca->ops->get_tag(dca, dev, cpu); spin_unlock_irqrestore(&dca_lock, flags); return tag; } /** * dca3_get_tag - return the dca tag to the requester device * for the given cpu (new api) * @dev - the device that wants dca service * @cpu - the cpuid as returned by get_cpu() */ u8 dca3_get_tag(struct device *dev, int cpu) { if (!dev) return -EFAULT; return dca_common_get_tag(dev, cpu); } EXPORT_SYMBOL_GPL(dca3_get_tag); /** * dca_get_tag - return the dca tag for the given cpu (old api) * @cpu - the cpuid as returned by get_cpu() */ u8 dca_get_tag(int cpu) { struct device *dev = NULL; return dca_common_get_tag(dev, cpu); } EXPORT_SYMBOL_GPL(dca_get_tag); /** * alloc_dca_provider - get data struct for describing a dca provider * @ops - pointer to struct of dca operation function pointers * @priv_size - size of extra mem to be added for provider's needs */ struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size) { struct dca_provider *dca; int alloc_size; alloc_size = (sizeof(*dca) + priv_size); dca = kzalloc(alloc_size, GFP_KERNEL); if (!dca) return NULL; dca->ops = ops; return dca; } EXPORT_SYMBOL_GPL(alloc_dca_provider); /** * free_dca_provider - release the dca provider data struct * @ops - pointer to struct of dca operation function pointers * @priv_size - size of extra mem to be added for provider's needs */ void free_dca_provider(struct dca_provider *dca) { kfree(dca); } EXPORT_SYMBOL_GPL(free_dca_provider); static BLOCKING_NOTIFIER_HEAD(dca_provider_chain); /** * register_dca_provider - register a dca provider * @dca - struct created by alloc_dca_provider() * @dev - device providing dca services */ int register_dca_provider(struct dca_provider *dca, struct device *dev) { int err; unsigned long flags; err = dca_sysfs_add_provider(dca, dev); if (err) return err; spin_lock_irqsave(&dca_lock, flags); list_add(&dca->node, &dca_providers); spin_unlock_irqrestore(&dca_lock, flags); blocking_notifier_call_chain(&dca_provider_chain, DCA_PROVIDER_ADD, NULL); return 0; } EXPORT_SYMBOL_GPL(register_dca_provider); /** * unregister_dca_provider - remove a dca provider * @dca - struct created by alloc_dca_provider() */ void unregister_dca_provider(struct dca_provider *dca) { unsigned long flags; blocking_notifier_call_chain(&dca_provider_chain, DCA_PROVIDER_REMOVE, NULL); spin_lock_irqsave(&dca_lock, flags); list_del(&dca->node); spin_unlock_irqrestore(&dca_lock, flags); dca_sysfs_remove_provider(dca); } EXPORT_SYMBOL_GPL(unregister_dca_provider); /** * dca_register_notify - register a client's notifier callback */ void dca_register_notify(struct notifier_block *nb) { blocking_notifier_chain_register(&dca_provider_chain, nb); } EXPORT_SYMBOL_GPL(dca_register_notify); /** * dca_unregister_notify - remove a client's notifier callback */ void dca_unregister_notify(struct notifier_block *nb) { blocking_notifier_chain_unregister(&dca_provider_chain, nb); } EXPORT_SYMBOL_GPL(dca_unregister_notify); static int __init dca_init(void) { printk(KERN_ERR "dca service started, version %s\n", DCA_VERSION); return dca_sysfs_init(); } static void __exit dca_exit(void) { dca_sysfs_exit(); } arch_initcall(dca_init); module_exit(dca_exit);