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 #include <linux/slab.h>
  31
  32 #define DCA_VERSION "1.12.1"
  33
  34 MODULE_VERSION(DCA_VERSION);
  35 MODULE_LICENSE("GPL");
  36 MODULE_AUTHOR("Intel Corporation");
  37
  38 static DEFINE_SPINLOCK(dca_lock);
  39
  40 static LIST_HEAD(dca_domains);
  41
  42 static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);
  43
  44 static int dca_providers_blocked;
  45
  46 static struct pci_bus *dca_pci_rc_from_dev(struct device *dev)
  47 {
  48         struct pci_dev *pdev = to_pci_dev(dev);
  49         struct pci_bus *bus = pdev->bus;
  50
  51         while (bus->parent)
  52                 bus = bus->parent;
  53
  54         return bus;
  55 }
  56
  57 static struct dca_domain *dca_allocate_domain(struct pci_bus *rc)
  58 {
  59         struct dca_domain *domain;
  60
  61         domain = kzalloc(sizeof(*domain), GFP_NOWAIT);
  62         if (!domain)
  63                 return NULL;
  64
  65         INIT_LIST_HEAD(&domain->dca_providers);
  66         domain->pci_rc = rc;
  67
  68         return domain;
  69 }
  70
  71 static void dca_free_domain(struct dca_domain *domain)
  72 {
  73         list_del(&domain->node);
  74         kfree(domain);
  75 }
  76
  77 static int dca_provider_ioat_ver_3_0(struct device *dev)
  78 {
  79         struct pci_dev *pdev = to_pci_dev(dev);
  80
  81         return ((pdev->vendor == PCI_VENDOR_ID_INTEL) &&
  82                 ((pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG0) ||
  83                 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG1) ||
  84                 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG2) ||
  85                 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG3) ||
  86                 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG4) ||
  87                 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG5) ||
  88                 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG6) ||
  89                 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG7)));
  90 }
  91
  92 static void unregister_dca_providers(void)
  93 {
  94         struct dca_provider *dca, *_dca;
  95         struct list_head unregistered_providers;
  96         struct dca_domain *domain;
  97         unsigned long flags;
  98
  99         blocking_notifier_call_chain(&dca_provider_chain,
 100                                      DCA_PROVIDER_REMOVE, NULL);
 101
 102         INIT_LIST_HEAD(&unregistered_providers);
 103
 104         spin_lock_irqsave(&dca_lock, flags);
 105
 106         if (list_empty(&dca_domains)) {
 107                 spin_unlock_irqrestore(&dca_lock, flags);
 108                 return;
 109         }
 110
 111         /* at this point only one domain in the list is expected */
 112         domain = list_first_entry(&dca_domains, struct dca_domain, node);
 113
 114         list_for_each_entry_safe(dca, _dca, &domain->dca_providers, node)
 115                 list_move(&dca->node, &unregistered_providers);
 116
 117         dca_free_domain(domain);
 118
 119         spin_unlock_irqrestore(&dca_lock, flags);
 120
 121         list_for_each_entry_safe(dca, _dca, &unregistered_providers, node) {
 122                 dca_sysfs_remove_provider(dca);
 123                 list_del(&dca->node);
 124         }
 125 }
 126
 127 static struct dca_domain *dca_find_domain(struct pci_bus *rc)
 128 {
 129         struct dca_domain *domain;
 130
 131         list_for_each_entry(domain, &dca_domains, node)
 132                 if (domain->pci_rc == rc)
 133                         return domain;
 134
 135         return NULL;
 136 }
 137
 138 static struct dca_domain *dca_get_domain(struct device *dev)
 139 {
 140         struct pci_bus *rc;
 141         struct dca_domain *domain;
 142
 143         rc = dca_pci_rc_from_dev(dev);
 144         domain = dca_find_domain(rc);
 145
 146         if (!domain) {
 147                 if (dca_provider_ioat_ver_3_0(dev) && !list_empty(&dca_domains)) {
 148                         dca_providers_blocked = 1;
 149                 } else {
 150                         domain = dca_allocate_domain(rc);
 151                         if (domain)
 152                                 list_add(&domain->node, &dca_domains);
 153                 }
 154         }
 155
 156         return domain;
 157 }
 158
 159 static struct dca_provider *dca_find_provider_by_dev(struct device *dev)
 160 {
 161         struct dca_provider *dca;
 162         struct pci_bus *rc;
 163         struct dca_domain *domain;
 164
 165         if (dev) {
 166                 rc = dca_pci_rc_from_dev(dev);
 167                 domain = dca_find_domain(rc);
 168                 if (!domain)
 169                         return NULL;
 170         } else {
 171                 if (!list_empty(&dca_domains))
 172                         domain = list_first_entry(&dca_domains,
 173                                                   struct dca_domain,
 174                                                   node);
 175                 else
 176                         return NULL;
 177         }
 178
 179         list_for_each_entry(dca, &domain->dca_providers, node)
 180                 if ((!dev) || (dca->ops->dev_managed(dca, dev)))
 181                         return dca;
 182
 183         return NULL;
 184 }
 185
 186 /**
 187  * dca_add_requester - add a dca client to the list
 188  * @dev - the device that wants dca service
 189  */
 190 int dca_add_requester(struct device *dev)
 191 {
 192         struct dca_provider *dca;
 193         int err, slot = -ENODEV;
 194         unsigned long flags;
 195         struct pci_bus *pci_rc;
 196         struct dca_domain *domain;
 197
 198         if (!dev)
 199                 return -EFAULT;
 200
 201         spin_lock_irqsave(&dca_lock, flags);
 202
 203         /* check if the requester has not been added already */
 204         dca = dca_find_provider_by_dev(dev);
 205         if (dca) {
 206                 spin_unlock_irqrestore(&dca_lock, flags);
 207                 return -EEXIST;
 208         }
 209
 210         pci_rc = dca_pci_rc_from_dev(dev);
 211         domain = dca_find_domain(pci_rc);
 212         if (!domain) {
 213                 spin_unlock_irqrestore(&dca_lock, flags);
 214                 return -ENODEV;
 215         }
 216
 217         list_for_each_entry(dca, &domain->dca_providers, node) {
 218                 slot = dca->ops->add_requester(dca, dev);
 219                 if (slot >= 0)
 220                         break;
 221         }
 222
 223         spin_unlock_irqrestore(&dca_lock, flags);
 224
 225         if (slot < 0)
 226                 return slot;
 227
 228         err = dca_sysfs_add_req(dca, dev, slot);
 229         if (err) {
 230                 spin_lock_irqsave(&dca_lock, flags);
 231                 if (dca == dca_find_provider_by_dev(dev))
 232                         dca->ops->remove_requester(dca, dev);
 233                 spin_unlock_irqrestore(&dca_lock, flags);
 234                 return err;
 235         }
 236
 237         return 0;
 238 }
 239 EXPORT_SYMBOL_GPL(dca_add_requester);
 240
 241 /**
 242  * dca_remove_requester - remove a dca client from the list
 243  * @dev - the device that wants dca service
 244  */
 245 int dca_remove_requester(struct device *dev)
 246 {
 247         struct dca_provider *dca;
 248         int slot;
 249         unsigned long flags;
 250
 251         if (!dev)
 252                 return -EFAULT;
 253
 254         spin_lock_irqsave(&dca_lock, flags);
 255         dca = dca_find_provider_by_dev(dev);
 256         if (!dca) {
 257                 spin_unlock_irqrestore(&dca_lock, flags);
 258                 return -ENODEV;
 259         }
 260         slot = dca->ops->remove_requester(dca, dev);
 261         spin_unlock_irqrestore(&dca_lock, flags);
 262
 263         if (slot < 0)
 264                 return slot;
 265
 266         dca_sysfs_remove_req(dca, slot);
 267
 268         return 0;
 269 }
 270 EXPORT_SYMBOL_GPL(dca_remove_requester);
 271
 272 /**
 273  * dca_common_get_tag - return the dca tag (serves both new and old api)
 274  * @dev - the device that wants dca service
 275  * @cpu - the cpuid as returned by get_cpu()
 276  */
 277 u8 dca_common_get_tag(struct device *dev, int cpu)
 278 {
 279         struct dca_provider *dca;
 280         u8 tag;
 281         unsigned long flags;
 282
 283         spin_lock_irqsave(&dca_lock, flags);
 284
 285         dca = dca_find_provider_by_dev(dev);
 286         if (!dca) {
 287                 spin_unlock_irqrestore(&dca_lock, flags);
 288                 return -ENODEV;
 289         }
 290         tag = dca->ops->get_tag(dca, dev, cpu);
 291
 292         spin_unlock_irqrestore(&dca_lock, flags);
 293         return tag;
 294 }
 295
 296 /**
 297  * dca3_get_tag - return the dca tag to the requester device
 298  *                for the given cpu (new api)
 299  * @dev - the device that wants dca service
 300  * @cpu - the cpuid as returned by get_cpu()
 301  */
 302 u8 dca3_get_tag(struct device *dev, int cpu)
 303 {
 304         if (!dev)
 305                 return -EFAULT;
 306
 307         return dca_common_get_tag(dev, cpu);
 308 }
 309 EXPORT_SYMBOL_GPL(dca3_get_tag);
 310
 311 /**
 312  * dca_get_tag - return the dca tag for the given cpu (old api)
 313  * @cpu - the cpuid as returned by get_cpu()
 314  */
 315 u8 dca_get_tag(int cpu)
 316 {
 317         struct device *dev = NULL;
 318
 319         return dca_common_get_tag(dev, cpu);
 320 }
 321 EXPORT_SYMBOL_GPL(dca_get_tag);
 322
 323 /**
 324  * alloc_dca_provider - get data struct for describing a dca provider
 325  * @ops - pointer to struct of dca operation function pointers
 326  * @priv_size - size of extra mem to be added for provider's needs
 327  */
 328 struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size)
 329 {
 330         struct dca_provider *dca;
 331         int alloc_size;
 332
 333         alloc_size = (sizeof(*dca) + priv_size);
 334         dca = kzalloc(alloc_size, GFP_KERNEL);
 335         if (!dca)
 336                 return NULL;
 337         dca->ops = ops;
 338
 339         return dca;
 340 }
 341 EXPORT_SYMBOL_GPL(alloc_dca_provider);
 342
 343 /**
 344  * free_dca_provider - release the dca provider data struct
 345  * @ops - pointer to struct of dca operation function pointers
 346  * @priv_size - size of extra mem to be added for provider's needs
 347  */
 348 void free_dca_provider(struct dca_provider *dca)
 349 {
 350         kfree(dca);
 351 }
 352 EXPORT_SYMBOL_GPL(free_dca_provider);
 353
 354 /**
 355  * register_dca_provider - register a dca provider
 356  * @dca - struct created by alloc_dca_provider()
 357  * @dev - device providing dca services
 358  */
 359 int register_dca_provider(struct dca_provider *dca, struct device *dev)
 360 {
 361         int err;
 362         unsigned long flags;
 363         struct dca_domain *domain;
 364
 365         spin_lock_irqsave(&dca_lock, flags);
 366         if (dca_providers_blocked) {
 367                 spin_unlock_irqrestore(&dca_lock, flags);
 368                 return -ENODEV;
 369         }
 370         spin_unlock_irqrestore(&dca_lock, flags);
 371
 372         err = dca_sysfs_add_provider(dca, dev);
 373         if (err)
 374                 return err;
 375
 376         spin_lock_irqsave(&dca_lock, flags);
 377         domain = dca_get_domain(dev);
 378         if (!domain) {
 379                 if (dca_providers_blocked) {
 380                         spin_unlock_irqrestore(&dca_lock, flags);
 381                         dca_sysfs_remove_provider(dca);
 382                         unregister_dca_providers();
 383                 } else {
 384                         spin_unlock_irqrestore(&dca_lock, flags);
 385                 }
 386                 return -ENODEV;
 387         }
 388         list_add(&dca->node, &domain->dca_providers);
 389         spin_unlock_irqrestore(&dca_lock, flags);
 390
 391         blocking_notifier_call_chain(&dca_provider_chain,
 392                                      DCA_PROVIDER_ADD, NULL);
 393         return 0;
 394 }
 395 EXPORT_SYMBOL_GPL(register_dca_provider);
 396
 397 /**
 398  * unregister_dca_provider - remove a dca provider
 399  * @dca - struct created by alloc_dca_provider()
 400  */
 401 void unregister_dca_provider(struct dca_provider *dca, struct device *dev)
 402 {
 403         unsigned long flags;
 404         struct pci_bus *pci_rc;
 405         struct dca_domain *domain;
 406
 407         blocking_notifier_call_chain(&dca_provider_chain,
 408                                      DCA_PROVIDER_REMOVE, NULL);
 409
 410         spin_lock_irqsave(&dca_lock, flags);
 411
 412         list_del(&dca->node);
 413
 414         pci_rc = dca_pci_rc_from_dev(dev);
 415         domain = dca_find_domain(pci_rc);
 416         if (list_empty(&domain->dca_providers))
 417                 dca_free_domain(domain);
 418
 419         spin_unlock_irqrestore(&dca_lock, flags);
 420
 421         dca_sysfs_remove_provider(dca);
 422 }
 423 EXPORT_SYMBOL_GPL(unregister_dca_provider);
 424
 425 /**
 426  * dca_register_notify - register a client's notifier callback
 427  */
 428 void dca_register_notify(struct notifier_block *nb)
 429 {
 430         blocking_notifier_chain_register(&dca_provider_chain, nb);
 431 }
 432 EXPORT_SYMBOL_GPL(dca_register_notify);
 433
 434 /**
 435  * dca_unregister_notify - remove a client's notifier callback
 436  */
 437 void dca_unregister_notify(struct notifier_block *nb)
 438 {
 439         blocking_notifier_chain_unregister(&dca_provider_chain, nb);
 440 }
 441 EXPORT_SYMBOL_GPL(dca_unregister_notify);
 442
 443 static int __init dca_init(void)
 444 {
 445         pr_info("dca service started, version %s\n", DCA_VERSION);
 446         return dca_sysfs_init();
 447 }
 448
 449 static void __exit dca_exit(void)
 450 {
 451         dca_sysfs_exit();
 452 }
 453
 454 arch_initcall(dca_init);
 455 module_exit(dca_exit);
 456