diff options
Diffstat (limited to 'drivers/dca/dca-core.c')
| -rw-r--r-- | drivers/dca/dca-core.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/drivers/dca/dca-core.c b/drivers/dca/dca-core.c new file mode 100644 index 00000000000..bf5b92f86df --- /dev/null +++ b/drivers/dca/dca-core.c @@ -0,0 +1,200 @@ +/* + * 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); + |