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_del(&dca->node);
 116                 list_add(&dca->node, &unregistered_providers);
 117         }
 118
 119         dca_free_domain(domain);
 120
 121         spin_unlock_irqrestore(&dca_lock, flags);
 122
 123         list_for_each_entry_safe(dca, _dca, &unregistered_providers, node) {
 124                 dca_sysfs_remove_provider(dca);
 125                 list_del(&dca->node);
 126         }
 127 }
 128
 129 static struct dca_domain *dca_find_domain(struct pci_bus *rc)
 130 {
 131         struct dca_domain *domain;
 132
 133         list_for_each_entry(domain, &dca_domains, node)
 134                 if (domain->pci_rc == rc)
 135                         return domain;
 136
 137         return NULL;
 138 }
 139
 140 static struct dca_domain *dca_get_domain(struct device *dev)
 141 {
 142         struct pci_bus *rc;
 143         struct dca_domain *domain;
 144
 145         rc = dca_pci_rc_from_dev(dev);
 146         domain = dca_find_domain(rc);
 147
 148         if (!domain) {
 149                 if (dca_provider_ioat_ver_3_0(dev) && !list_empty(&dca_domains)) {
 150                         dca_providers_blocked = 1;
 151                 } else {
 152                         domain = dca_allocate_domain(rc);
 153                         if (domain)
 154                                 list_add(&domain->node, &dca_domains);
 155                 }
 156         }
 157
 158         return domain;
 159 }
 160
 161 static struct dca_provider *dca_find_provider_by_dev(struct device *dev)
 162 {
 163         struct dca_provider *dca;
 164         struct pci_bus *rc;
 165         struct dca_domain *domain;
 166
 167         if (dev) {
 168                 rc = dca_pci_rc_from_dev(dev);
 169                 domain = dca_find_domain(rc);
 170                 if (!domain)
 171                         return NULL;
 172         } else {
 173                 if (!list_empty(&dca_domains))
 174                         domain = list_first_entry(&dca_domains,
 175                                                   struct dca_domain,
 176                                                   node);
 177                 else
 178                         return NULL;
 179         }
 180
 181         list_for_each_entry(dca, &domain->dca_providers, node)
 182                 if ((!dev) || (dca->ops->dev_managed(dca, dev)))
 183                         return dca;
 184
 185         return NULL;
 186 }
 187
 188 /**
 189  * dca_add_requester - add a dca client to the list
 190  * @dev - the device that wants dca service
 191  */
 192 int dca_add_requester(struct device *dev)
 193 {
 194         struct dca_provider *dca;
 195         int err, slot = -ENODEV;
 196         unsigned long flags;
 197         struct pci_bus *pci_rc;
 198         struct dca_domain *domain;
 199
 200         if (!dev)
 201                 return -EFAULT;
 202
 203         spin_lock_irqsave(&dca_lock, flags);
 204
 205         /* check if the requester has not been added already */
 206         dca = dca_find_provider_by_dev(dev);
 207         if (dca) {
 208                 spin_unlock_irqrestore(&dca_lock, flags);
 209                 return -EEXIST;
 210         }
 211
 212         pci_rc = dca_pci_rc_from_dev(dev);
 213         domain = dca_find_domain(pci_rc);
 214         if (!domain) {
 215                 spin_unlock_irqrestore(&dca_lock, flags);
 216                 return -ENODEV;
 217         }
 218
 219         list_for_each_entry(dca, &domain->dca_providers, node) {
 220                 slot = dca->ops->add_requester(dca, dev);
 221                 if (slot >= 0)
 222                         break;
 223         }
 224
 225         spin_unlock_irqrestore(&dca_lock, flags);
 226
 227         if (slot < 0)
 228                 return slot;
 229
 230         err = dca_sysfs_add_req(dca, dev, slot);
 231         if (err) {
 232                 spin_lock_irqsave(&dca_lock, flags);
 233                 if (dca == dca_find_provider_by_dev(dev))
 234                         dca->ops->remove_requester(dca, dev);
 235                 spin_unlock_irqrestore(&dca_lock, flags);
 236                 return err;
 237         }
 238
 239         return 0;
 240 }
 241 EXPORT_SYMBOL_GPL(dca_add_requester);
 242
 243 /**
 244  * dca_remove_requester - remove a dca client from the list
 245  * @dev - the device that wants dca service
 246  */
 247 int dca_remove_requester(struct device *dev)
 248 {
 249         struct dca_provider *dca;
 250         int slot;
 251         unsigned long flags;
 252
 253         if (!dev)
 254                 return -EFAULT;
 255
 256         spin_lock_irqsave(&dca_lock, flags);
 257         dca = dca_find_provider_by_dev(dev);
 258         if (!dca) {
 259                 spin_unlock_irqrestore(&dca_lock, flags);
 260                 return -ENODEV;
 261         }
 262         slot = dca->ops->remove_requester(dca, dev);
 263         spin_unlock_irqrestore(&dca_lock, flags);
 264
 265         if (slot < 0)
 266                 return slot;
 267
 268         dca_sysfs_remove_req(dca, slot);
 269
 270         return 0;
 271 }
 272 EXPORT_SYMBOL_GPL(dca_remove_requester);
 273
 274 /**
 275  * dca_common_get_tag - return the dca tag (serves both new and old api)
 276  * @dev - the device that wants dca service
 277  * @cpu - the cpuid as returned by get_cpu()
 278  */
 279 u8 dca_common_get_tag(struct device *dev, int cpu)
 280 {
 281         struct dca_provider *dca;
 282         u8 tag;
 283         unsigned long flags;
 284
 285         spin_lock_irqsave(&dca_lock, flags);
 286
 287         dca = dca_find_provider_by_dev(dev);
 288         if (!dca) {
 289                 spin_unlock_irqrestore(&dca_lock, flags);
 290                 return -ENODEV;
 291         }
 292         tag = dca->ops->get_tag(dca, dev, cpu);
 293
 294         spin_unlock_irqrestore(&dca_lock, flags);
 295         return tag;
 296 }
 297
 298 /**
 299  * dca3_get_tag - return the dca tag to the requester device
 300  *                for the given cpu (new api)
 301  * @dev - the device that wants dca service
 302  * @cpu - the cpuid as returned by get_cpu()
 303  */
 304 u8 dca3_get_tag(struct device *dev, int cpu)
 305 {
 306         if (!dev)
 307                 return -EFAULT;
 308
 309         return dca_common_get_tag(dev, cpu);
 310 }
 311 EXPORT_SYMBOL_GPL(dca3_get_tag);
 312
 313 /**
 314  * dca_get_tag - return the dca tag for the given cpu (old api)
 315  * @cpu - the cpuid as returned by get_cpu()
 316  */
 317 u8 dca_get_tag(int cpu)
 318 {
 319         struct device *dev = NULL;
 320
 321         return dca_common_get_tag(dev, cpu);
 322 }
 323 EXPORT_SYMBOL_GPL(dca_get_tag);
 324
 325 /**
 326  * alloc_dca_provider - get data struct for describing a dca provider
 327  * @ops - pointer to struct of dca operation function pointers
 328  * @priv_size - size of extra mem to be added for provider's needs
 329  */
 330 struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size)
 331 {
 332         struct dca_provider *dca;
 333         int alloc_size;
 334
 335         alloc_size = (sizeof(*dca) + priv_size);
 336         dca = kzalloc(alloc_size, GFP_KERNEL);
 337         if (!dca)
 338                 return NULL;
 339         dca->ops = ops;
 340
 341         return dca;
 342 }
 343 EXPORT_SYMBOL_GPL(alloc_dca_provider);
 344
 345 /**
 346  * free_dca_provider - release the dca provider data struct
 347  * @ops - pointer to struct of dca operation function pointers
 348  * @priv_size - size of extra mem to be added for provider's needs
 349  */
 350 void free_dca_provider(struct dca_provider *dca)
 351 {
 352         kfree(dca);
 353 }
 354 EXPORT_SYMBOL_GPL(free_dca_provider);
 355
 356 /**
 357  * register_dca_provider - register a dca provider
 358  * @dca - struct created by alloc_dca_provider()
 359  * @dev - device providing dca services
 360  */
 361 int register_dca_provider(struct dca_provider *dca, struct device *dev)
 362 {
 363         int err;
 364         unsigned long flags;
 365         struct dca_domain *domain;
 366
 367         spin_lock_irqsave(&dca_lock, flags);
 368         if (dca_providers_blocked) {
 369                 spin_unlock_irqrestore(&dca_lock, flags);
 370                 return -ENODEV;
 371         }
 372         spin_unlock_irqrestore(&dca_lock, flags);
 373
 374         err = dca_sysfs_add_provider(dca, dev);
 375         if (err)
 376                 return err;
 377
 378         spin_lock_irqsave(&dca_lock, flags);
 379         domain = dca_get_domain(dev);
 380         if (!domain) {
 381                 if (dca_providers_blocked) {
 382                         spin_unlock_irqrestore(&dca_lock, flags);
 383                         dca_sysfs_remove_provider(dca);
 384                         unregister_dca_providers();
 385                 } else {
 386                         spin_unlock_irqrestore(&dca_lock, flags);
 387                 }
 388                 return -ENODEV;
 389         }
 390         list_add(&dca->node, &domain->dca_providers);
 391         spin_unlock_irqrestore(&dca_lock, flags);
 392
 393         blocking_notifier_call_chain(&dca_provider_chain,
 394                                      DCA_PROVIDER_ADD, NULL);
 395         return 0;
 396 }
 397 EXPORT_SYMBOL_GPL(register_dca_provider);
 398
 399 /**
 400  * unregister_dca_provider - remove a dca provider
 401  * @dca - struct created by alloc_dca_provider()
 402  */
 403 void unregister_dca_provider(struct dca_provider *dca, struct device *dev)
 404 {
 405         unsigned long flags;
 406         struct pci_bus *pci_rc;
 407         struct dca_domain *domain;
 408
 409         blocking_notifier_call_chain(&dca_provider_chain,
 410                                      DCA_PROVIDER_REMOVE, NULL);
 411
 412         spin_lock_irqsave(&dca_lock, flags);
 413
 414         list_del(&dca->node);
 415
 416         pci_rc = dca_pci_rc_from_dev(dev);
 417         domain = dca_find_domain(pci_rc);
 418         if (list_empty(&domain->dca_providers))
 419                 dca_free_domain(domain);
 420
 421         spin_unlock_irqrestore(&dca_lock, flags);
 422
 423         dca_sysfs_remove_provider(dca);
 424 }
 425 EXPORT_SYMBOL_GPL(unregister_dca_provider);
 426
 427 /**
 428  * dca_register_notify - register a client's notifier callback
 429  */
 430 void dca_register_notify(struct notifier_block *nb)
 431 {
 432         blocking_notifier_chain_register(&dca_provider_chain, nb);
 433 }
 434 EXPORT_SYMBOL_GPL(dca_register_notify);
 435
 436 /**
 437  * dca_unregister_notify - remove a client's notifier callback
 438  */
 439 void dca_unregister_notify(struct notifier_block *nb)
 440 {
 441         blocking_notifier_chain_unregister(&dca_provider_chain, nb);
 442 }
 443 EXPORT_SYMBOL_GPL(dca_unregister_notify);
 444
 445 static int __init dca_init(void)
 446 {
 447         pr_info("dca service started, version %s\n", DCA_VERSION);
 448         return dca_sysfs_init();
 449 }
 450
 451 static void __exit dca_exit(void)
 452 {
 453         dca_sysfs_exit();
 454 }
 455
 456 arch_initcall(dca_init);
 457 module_exit(dca_exit);
 458