/*
* Copyright(c) 2007 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>
MODULE_LICENSE("GPL");
/* For now we're assuming a single, global, DCA provider for the system. */
static DEFINE_SPINLOCK(dca_lock);
static struct dca_provider *global_dca = NULL;
/**
* dca_add_requester - add a dca client to the list
* @dev - the device that wants dca service
*/
int dca_add_requester(struct device *dev)
{
int err, slot;
if (!global_dca)
return -ENODEV;
spin_lock(&dca_lock);
slot = global_dca->ops->add_requester(global_dca, dev);
spin_unlock(&dca_lock);
if (slot < 0)
return slot;
err = dca_sysfs_add_req(global_dca, dev, slot);
if (err) {
spin_lock(&dca_lock);
global_dca->ops->remove_requester(global_dca, dev);
spin_unlock(&dca_lock);
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)
{
int slot;
if (!global_dca)
return -ENODEV;
spin_lock(&dca_lock);
slot = global_dca->ops->remove_requester(global_dca, dev);
spin_unlock(&dca_lock);
if (slot < 0)
return slot;
dca_sysfs_remove_req(global_dca, slot);
return 0;
}
EXPORT_SYMBOL_GPL(dca_remove_requester);
/**
* dca_get_tag - return the dca tag for the given cpu
* @cpu - the cpuid as returned by get_cpu()
*/
u8 dca_get_tag(int cpu)
{
if (!global_dca)
return -ENODEV;
return global_dca->ops->get_tag(global_dca, 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;
if (global_dca)
return -EEXIST;
err = dca_sysfs_add_provider(dca, dev);
if (err)
return err;
global_dca = dca;
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)
{
if (!global_dca)
return;
blocking_notifier_call_chain(&dca_provider_chain,
DCA_PROVIDER_REMOVE, NULL);
global_dca = NULL;
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)
{
return dca_sysfs_init();
}
static void __exit dca_exit(void)
{
dca_sysfs_exit();
}
module_init(dca_init);
module_exit(dca_exit);
