drivers/dca/dca-core.c

   1 /*
   2  * Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the Free
   6  * Software Foundation; either version 2 of the License, or (at your option)
   7  * any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc., 59
  16  * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  *
  18  * The full GNU General Public License is included in this distribution in the
  19  * file called COPYING.
  20  */
  21
  22 /*
  23  * This driver supports an interface for DCA clients and providers to meet.
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/notifier.h>
  28 #include <linux/device.h>
  29 #include <linux/dca.h>
  30
  31 #define DCA_VERSION "1.12.1"
  32
  33 MODULE_VERSION(DCA_VERSION);
  34 MODULE_LICENSE("GPL");
  35 MODULE_AUTHOR("Intel Corporation");
  36
  37 static DEFINE_SPINLOCK(dca_lock);
  38
  39 static LIST_HEAD(dca_domains);
  40
  41 static struct pci_bus *dca_pci_rc_from_dev(struct device *dev)
  42 {
  43         struct pci_dev *pdev = to_pci_dev(dev);
  44         struct pci_bus *bus = pdev->bus;
  45
  46         while (bus->parent)
  47                 bus = bus->parent;
  48
  49         return bus;
  50 }
  51
  52 static struct dca_domain *dca_allocate_domain(struct pci_bus *rc)
  53 {
  54         struct dca_domain *domain;
  55
  56         domain = kzalloc(sizeof(*domain), GFP_NOWAIT);
  57         if (!domain)
  58                 return NULL;
  59
  60         INIT_LIST_HEAD(&domain->dca_providers);
  61         domain->pci_rc = rc;
  62
  63         return domain;
  64 }
  65
  66 static void dca_free_domain(struct dca_domain *domain)
  67 {
  68         list_del(&domain->node);
  69         kfree(domain);
  70 }
  71
  72 static struct dca_domain *dca_find_domain(struct pci_bus *rc)
  73 {
  74         struct dca_domain *domain;
  75
  76         list_for_each_entry(domain, &dca_domains, node)
  77                 if (domain->pci_rc == rc)
  78                         return domain;
  79
  80         return NULL;
  81 }
  82
  83 static struct dca_domain *dca_get_domain(struct device *dev)
  84 {
  85         struct pci_bus *rc;
  86         struct dca_domain *domain;
  87
  88         rc = dca_pci_rc_from_dev(dev);
  89         domain = dca_find_domain(rc);
  90
  91         if (!domain) {
  92                 domain = dca_allocate_domain(rc);
  93                 if (domain)
  94                         list_add(&domain->node, &dca_domains);
  95         }
  96
  97         return domain;
  98 }
  99
 100 static struct dca_provider *dca_find_provider_by_dev(struct device *dev)
 101 {
 102         struct dca_provider *dca;
 103         struct pci_bus *rc;
 104         struct dca_domain *domain;
 105
 106         if (dev) {
 107                 rc = dca_pci_rc_from_dev(dev);
 108                 domain = dca_find_domain(rc);
 109                 if (!domain)
 110                         return NULL;
 111         } else {
 112                 if (!list_empty(&dca_domains))
 113                         domain = list_first_entry(&dca_domains,
 114                                                   struct dca_domain,
 115                                                   node);
 116                 else
 117                         return NULL;
 118         }
 119
 120         list_for_each_entry(dca, &domain->dca_providers, node)
 121                 if ((!dev) || (dca->ops->dev_managed(dca, dev)))
 122                         return dca;
 123
 124         return NULL;
 125 }
 126
 127 /**
 128  * dca_add_requester - add a dca client to the list
 129  * @dev - the device that wants dca service
 130  */
 131 int dca_add_requester(struct device *dev)
 132 {
 133         struct dca_provider *dca;
 134         int err, slot = -ENODEV;
 135         unsigned long flags;
 136         struct pci_bus *pci_rc;
 137         struct dca_domain *domain;
 138
 139         if (!dev)
 140                 return -EFAULT;
 141
 142         spin_lock_irqsave(&dca_lock, flags);
 143
 144         /* check if the requester has not been added already */
 145         dca = dca_find_provider_by_dev(dev);
 146         if (dca) {
 147                 spin_unlock_irqrestore(&dca_lock, flags);
 148                 return -EEXIST;
 149         }
 150
 151         pci_rc = dca_pci_rc_from_dev(dev);
 152         domain = dca_find_domain(pci_rc);
 153         if (!domain) {
 154                 spin_unlock_irqrestore(&dca_lock, flags);
 155                 return -ENODEV;
 156         }
 157
 158         list_for_each_entry(dca, &domain->dca_providers, node) {
 159                 slot = dca->ops->add_requester(dca, dev);
 160                 if (slot >= 0)
 161                         break;
 162         }
 163
 164         spin_unlock_irqrestore(&dca_lock, flags);
 165
 166         if (slot < 0)
 167                 return slot;
 168
 169         err = dca_sysfs_add_req(dca, dev, slot);
 170         if (err) {
 171                 spin_lock_irqsave(&dca_lock, flags);
 172                 if (dca == dca_find_provider_by_dev(dev))
 173                         dca->ops->remove_requester(dca, dev);
 174                 spin_unlock_irqrestore(&dca_lock, flags);
 175                 return err;
 176         }
 177
 178         return 0;
 179 }
 180 EXPORT_SYMBOL_GPL(dca_add_requester);
 181
 182 /**
 183  * dca_remove_requester - remove a dca client from the list
 184  * @dev - the device that wants dca service
 185  */
 186 int dca_remove_requester(struct device *dev)
 187 {
 188         struct dca_provider *dca;
 189         int slot;
 190         unsigned long flags;
 191
 192         if (!dev)
 193                 return -EFAULT;
 194
 195         spin_lock_irqsave(&dca_lock, flags);
 196         dca = dca_find_provider_by_dev(dev);
 197         if (!dca) {
 198                 spin_unlock_irqrestore(&dca_lock, flags);
 199                 return -ENODEV;
 200         }
 201         slot = dca->ops->remove_requester(dca, dev);
 202         spin_unlock_irqrestore(&dca_lock, flags);
 203
 204         if (slot < 0)
 205                 return slot;
 206
 207         dca_sysfs_remove_req(dca, slot);
 208
 209         return 0;
 210 }
 211 EXPORT_SYMBOL_GPL(dca_remove_requester);
 212
 213 /**
 214  * dca_common_get_tag - return the dca tag (serves both new and old api)
 215  * @dev - the device that wants dca service
 216  * @cpu - the cpuid as returned by get_cpu()
 217  */
 218 u8 dca_common_get_tag(struct device *dev, int cpu)
 219 {
 220         struct dca_provider *dca;
 221         u8 tag;
 222         unsigned long flags;
 223
 224         spin_lock_irqsave(&dca_lock, flags);
 225
 226         dca = dca_find_provider_by_dev(dev);
 227         if (!dca) {
 228                 spin_unlock_irqrestore(&dca_lock, flags);
 229                 return -ENODEV;
 230         }
 231         tag = dca->ops->get_tag(dca, dev, cpu);
 232
 233         spin_unlock_irqrestore(&dca_lock, flags);
 234         return tag;
 235 }
 236
 237 /**
 238  * dca3_get_tag - return the dca tag to the requester device
 239  *                for the given cpu (new api)
 240  * @dev - the device that wants dca service
 241  * @cpu - the cpuid as returned by get_cpu()
 242  */
 243 u8 dca3_get_tag(struct device *dev, int cpu)
 244 {
 245         if (!dev)
 246                 return -EFAULT;
 247
 248         return dca_common_get_tag(dev, cpu);
 249 }
 250 EXPORT_SYMBOL_GPL(dca3_get_tag);
 251
 252 /**
 253  * dca_get_tag - return the dca tag for the given cpu (old api)
 254  * @cpu - the cpuid as returned by get_cpu()
 255  */
 256 u8 dca_get_tag(int cpu)
 257 {
 258         struct device *dev = NULL;
 259
 260         return dca_common_get_tag(dev, cpu);
 261 }
 262 EXPORT_SYMBOL_GPL(dca_get_tag);
 263
 264 /**
 265  * alloc_dca_provider - get data struct for describing a dca provider
 266  * @ops - pointer to struct of dca operation function pointers
 267  * @priv_size - size of extra mem to be added for provider's needs
 268  */
 269 struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size)
 270 {
 271         struct dca_provider *dca;
 272         int alloc_size;
 273
 274         alloc_size = (sizeof(*dca) + priv_size);
 275         dca = kzalloc(alloc_size, GFP_KERNEL);
 276         if (!dca)
 277                 return NULL;
 278         dca->ops = ops;
 279
 280         return dca;
 281 }
 282 EXPORT_SYMBOL_GPL(alloc_dca_provider);
 283
 284 /**
 285  * free_dca_provider - release the dca provider data struct
 286  * @ops - pointer to struct of dca operation function pointers
 287  * @priv_size - size of extra mem to be added for provider's needs
 288  */
 289 void free_dca_provider(struct dca_provider *dca)
 290 {
 291         kfree(dca);
 292 }
 293 EXPORT_SYMBOL_GPL(free_dca_provider);
 294
 295 static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);
 296
 297 /**
 298  * register_dca_provider - register a dca provider
 299  * @dca - struct created by alloc_dca_provider()
 300  * @dev - device providing dca services
 301  */
 302 int register_dca_provider(struct dca_provider *dca, struct device *dev)
 303 {
 304         int err;
 305         unsigned long flags;
 306         struct dca_domain *domain;
 307
 308         err = dca_sysfs_add_provider(dca, dev);
 309         if (err)
 310                 return err;
 311
 312         spin_lock_irqsave(&dca_lock, flags);
 313         domain = dca_get_domain(dev);
 314         if (!domain) {
 315                 spin_unlock_irqrestore(&dca_lock, flags);
 316                 return -ENODEV;
 317         }
 318         list_add(&dca->node, &domain->dca_providers);
 319         spin_unlock_irqrestore(&dca_lock, flags);
 320
 321         blocking_notifier_call_chain(&dca_provider_chain,
 322                                      DCA_PROVIDER_ADD, NULL);
 323         return 0;
 324 }
 325 EXPORT_SYMBOL_GPL(register_dca_provider);
 326
 327 /**
 328  * unregister_dca_provider - remove a dca provider
 329  * @dca - struct created by alloc_dca_provider()
 330  */
 331 void unregister_dca_provider(struct dca_provider *dca, struct device *dev)
 332 {
 333         unsigned long flags;
 334         struct pci_bus *pci_rc;
 335         struct dca_domain *domain;
 336
 337         blocking_notifier_call_chain(&dca_provider_chain,
 338                                      DCA_PROVIDER_REMOVE, NULL);
 339
 340         spin_lock_irqsave(&dca_lock, flags);
 341
 342         list_del(&dca->node);
 343
 344         pci_rc = dca_pci_rc_from_dev(dev);
 345         domain = dca_find_domain(pci_rc);
 346         if (list_empty(&domain->dca_providers))
 347                 dca_free_domain(domain);
 348
 349         spin_unlock_irqrestore(&dca_lock, flags);
 350
 351         dca_sysfs_remove_provider(dca);
 352 }
 353 EXPORT_SYMBOL_GPL(unregister_dca_provider);
 354
 355 /**
 356  * dca_register_notify - register a client's notifier callback
 357  */
 358 void dca_register_notify(struct notifier_block *nb)
 359 {
 360         blocking_notifier_chain_register(&dca_provider_chain, nb);
 361 }
 362 EXPORT_SYMBOL_GPL(dca_register_notify);
 363
 364 /**
 365  * dca_unregister_notify - remove a client's notifier callback
 366  */
 367 void dca_unregister_notify(struct notifier_block *nb)
 368 {
 369         blocking_notifier_chain_unregister(&dca_provider_chain, nb);
 370 }
 371 EXPORT_SYMBOL_GPL(dca_unregister_notify);
 372
 373 static int __init dca_init(void)
 374 {
 375         printk(KERN_ERR "dca service started, version %s\n", DCA_VERSION);
 376         return dca_sysfs_init();
 377 }
 378
 379 static void __exit dca_exit(void)
 380 {
 381         dca_sysfs_exit();
 382 }
 383
 384 arch_initcall(dca_init);
 385 module_exit(dca_exit);
 386