drivers/pci/ats.c

   1 /*
   2  * drivers/pci/ats.c
   3  *
   4  * Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
   5  * Copyright (C) 2011 Advanced Micro Devices,
   6  *
   7  * PCI Express I/O Virtualization (IOV) support.
   8  *   Address Translation Service 1.0
   9  *   Page Request Interface added by Joerg Roedel <joerg.roedel@amd.com>
  10  *   PASID support added by Joerg Roedel <joerg.roedel@amd.com>
  11  */
  12
  13 #include <linux/export.h>
  14 #include <linux/pci-ats.h>
  15 #include <linux/pci.h>
  16 #include <linux/slab.h>
  17
  18 #include "pci.h"
  19
  20 static int ats_alloc_one(struct pci_dev *dev, int ps)
  21 {
  22         int pos;
  23         u16 cap;
  24         struct pci_ats *ats;
  25
  26         pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
  27         if (!pos)
  28                 return -ENODEV;
  29
  30         ats = kzalloc(sizeof(*ats), GFP_KERNEL);
  31         if (!ats)
  32                 return -ENOMEM;
  33
  34         ats->pos = pos;
  35         ats->stu = ps;
  36         pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
  37         ats->qdep = PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
  38                                             PCI_ATS_MAX_QDEP;
  39         dev->ats = ats;
  40
  41         return 0;
  42 }
  43
  44 static void ats_free_one(struct pci_dev *dev)
  45 {
  46         kfree(dev->ats);
  47         dev->ats = NULL;
  48 }
  49
  50 /**
  51  * pci_enable_ats - enable the ATS capability
  52  * @dev: the PCI device
  53  * @ps: the IOMMU page shift
  54  *
  55  * Returns 0 on success, or negative on failure.
  56  */
  57 int pci_enable_ats(struct pci_dev *dev, int ps)
  58 {
  59         int rc;
  60         u16 ctrl;
  61
  62         BUG_ON(dev->ats && dev->ats->is_enabled);
  63
  64         if (ps < PCI_ATS_MIN_STU)
  65                 return -EINVAL;
  66
  67         if (dev->is_physfn || dev->is_virtfn) {
  68                 struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;
  69
  70                 mutex_lock(&pdev->sriov->lock);
  71                 if (pdev->ats)
  72                         rc = pdev->ats->stu == ps ? 0 : -EINVAL;
  73                 else
  74                         rc = ats_alloc_one(pdev, ps);
  75
  76                 if (!rc)
  77                         pdev->ats->ref_cnt++;
  78                 mutex_unlock(&pdev->sriov->lock);
  79                 if (rc)
  80                         return rc;
  81         }
  82
  83         if (!dev->is_physfn) {
  84                 rc = ats_alloc_one(dev, ps);
  85                 if (rc)
  86                         return rc;
  87         }
  88
  89         ctrl = PCI_ATS_CTRL_ENABLE;
  90         if (!dev->is_virtfn)
  91                 ctrl |= PCI_ATS_CTRL_STU(ps - PCI_ATS_MIN_STU);
  92         pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
  93
  94         dev->ats->is_enabled = 1;
  95
  96         return 0;
  97 }
  98 EXPORT_SYMBOL_GPL(pci_enable_ats);
  99
 100 /**
 101  * pci_disable_ats - disable the ATS capability
 102  * @dev: the PCI device
 103  */
 104 void pci_disable_ats(struct pci_dev *dev)
 105 {
 106         u16 ctrl;
 107
 108         BUG_ON(!dev->ats || !dev->ats->is_enabled);
 109
 110         pci_read_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, &ctrl);
 111         ctrl &= ~PCI_ATS_CTRL_ENABLE;
 112         pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
 113
 114         dev->ats->is_enabled = 0;
 115
 116         if (dev->is_physfn || dev->is_virtfn) {
 117                 struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;
 118
 119                 mutex_lock(&pdev->sriov->lock);
 120                 pdev->ats->ref_cnt--;
 121                 if (!pdev->ats->ref_cnt)
 122                         ats_free_one(pdev);
 123                 mutex_unlock(&pdev->sriov->lock);
 124         }
 125
 126         if (!dev->is_physfn)
 127                 ats_free_one(dev);
 128 }
 129 EXPORT_SYMBOL_GPL(pci_disable_ats);
 130
 131 void pci_restore_ats_state(struct pci_dev *dev)
 132 {
 133         u16 ctrl;
 134
 135         if (!pci_ats_enabled(dev))
 136                 return;
 137         if (!pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS))
 138                 BUG();
 139
 140         ctrl = PCI_ATS_CTRL_ENABLE;
 141         if (!dev->is_virtfn)
 142                 ctrl |= PCI_ATS_CTRL_STU(dev->ats->stu - PCI_ATS_MIN_STU);
 143
 144         pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
 145 }
 146 EXPORT_SYMBOL_GPL(pci_restore_ats_state);
 147
 148 /**
 149  * pci_ats_queue_depth - query the ATS Invalidate Queue Depth
 150  * @dev: the PCI device
 151  *
 152  * Returns the queue depth on success, or negative on failure.
 153  *
 154  * The ATS spec uses 0 in the Invalidate Queue Depth field to
 155  * indicate that the function can accept 32 Invalidate Request.
 156  * But here we use the `real' values (i.e. 1~32) for the Queue
 157  * Depth; and 0 indicates the function shares the Queue with
 158  * other functions (doesn't exclusively own a Queue).
 159  */
 160 int pci_ats_queue_depth(struct pci_dev *dev)
 161 {
 162         int pos;
 163         u16 cap;
 164
 165         if (dev->is_virtfn)
 166                 return 0;
 167
 168         if (dev->ats)
 169                 return dev->ats->qdep;
 170
 171         pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
 172         if (!pos)
 173                 return -ENODEV;
 174
 175         pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
 176
 177         return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
 178                                        PCI_ATS_MAX_QDEP;
 179 }
 180 EXPORT_SYMBOL_GPL(pci_ats_queue_depth);
 181
 182 #ifdef CONFIG_PCI_PRI
 183 /**
 184  * pci_enable_pri - Enable PRI capability
 185  * @ pdev: PCI device structure
 186  *
 187  * Returns 0 on success, negative value on error
 188  */
 189 int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
 190 {
 191         u16 control, status;
 192         u32 max_requests;
 193         int pos;
 194
 195         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
 196         if (!pos)
 197                 return -EINVAL;
 198
 199         pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
 200         pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
 201         if ((control & PCI_PRI_CTRL_ENABLE) ||
 202             !(status & PCI_PRI_STATUS_STOPPED))
 203                 return -EBUSY;
 204
 205         pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ, &max_requests);
 206         reqs = min(max_requests, reqs);
 207         pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
 208
 209         control |= PCI_PRI_CTRL_ENABLE;
 210         pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
 211
 212         return 0;
 213 }
 214 EXPORT_SYMBOL_GPL(pci_enable_pri);
 215
 216 /**
 217  * pci_disable_pri - Disable PRI capability
 218  * @pdev: PCI device structure
 219  *
 220  * Only clears the enabled-bit, regardless of its former value
 221  */
 222 void pci_disable_pri(struct pci_dev *pdev)
 223 {
 224         u16 control;
 225         int pos;
 226
 227         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
 228         if (!pos)
 229                 return;
 230
 231         pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
 232         control &= ~PCI_PRI_CTRL_ENABLE;
 233         pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
 234 }
 235 EXPORT_SYMBOL_GPL(pci_disable_pri);
 236
 237 /**
 238  * pci_pri_enabled - Checks if PRI capability is enabled
 239  * @pdev: PCI device structure
 240  *
 241  * Returns true if PRI is enabled on the device, false otherwise
 242  */
 243 bool pci_pri_enabled(struct pci_dev *pdev)
 244 {
 245         u16 control;
 246         int pos;
 247
 248         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
 249         if (!pos)
 250                 return false;
 251
 252         pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
 253
 254         return (control & PCI_PRI_CTRL_ENABLE) ? true : false;
 255 }
 256 EXPORT_SYMBOL_GPL(pci_pri_enabled);
 257
 258 /**
 259  * pci_reset_pri - Resets device's PRI state
 260  * @pdev: PCI device structure
 261  *
 262  * The PRI capability must be disabled before this function is called.
 263  * Returns 0 on success, negative value on error.
 264  */
 265 int pci_reset_pri(struct pci_dev *pdev)
 266 {
 267         u16 control;
 268         int pos;
 269
 270         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
 271         if (!pos)
 272                 return -EINVAL;
 273
 274         pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
 275         if (control & PCI_PRI_CTRL_ENABLE)
 276                 return -EBUSY;
 277
 278         control |= PCI_PRI_CTRL_RESET;
 279
 280         pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
 281
 282         return 0;
 283 }
 284 EXPORT_SYMBOL_GPL(pci_reset_pri);
 285
 286 /**
 287  * pci_pri_stopped - Checks whether the PRI capability is stopped
 288  * @pdev: PCI device structure
 289  *
 290  * Returns true if the PRI capability on the device is disabled and the
 291  * device has no outstanding PRI requests, false otherwise. The device
 292  * indicates this via the STOPPED bit in the status register of the
 293  * capability.
 294  * The device internal state can be cleared by resetting the PRI state
 295  * with pci_reset_pri(). This can force the capability into the STOPPED
 296  * state.
 297  */
 298 bool pci_pri_stopped(struct pci_dev *pdev)
 299 {
 300         u16 control, status;
 301         int pos;
 302
 303         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
 304         if (!pos)
 305                 return true;
 306
 307         pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
 308         pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
 309
 310         if (control & PCI_PRI_CTRL_ENABLE)
 311                 return false;
 312
 313         return (status & PCI_PRI_STATUS_STOPPED) ? true : false;
 314 }
 315 EXPORT_SYMBOL_GPL(pci_pri_stopped);
 316
 317 /**
 318  * pci_pri_status - Request PRI status of a device
 319  * @pdev: PCI device structure
 320  *
 321  * Returns negative value on failure, status on success. The status can
 322  * be checked against status-bits. Supported bits are currently:
 323  * PCI_PRI_STATUS_RF:      Response failure
 324  * PCI_PRI_STATUS_UPRGI:   Unexpected Page Request Group Index
 325  * PCI_PRI_STATUS_STOPPED: PRI has stopped
 326  */
 327 int pci_pri_status(struct pci_dev *pdev)
 328 {
 329         u16 status, control;
 330         int pos;
 331
 332         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
 333         if (!pos)
 334                 return -EINVAL;
 335
 336         pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
 337         pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
 338
 339         /* Stopped bit is undefined when enable == 1, so clear it */
 340         if (control & PCI_PRI_CTRL_ENABLE)
 341                 status &= ~PCI_PRI_STATUS_STOPPED;
 342
 343         return status;
 344 }
 345 EXPORT_SYMBOL_GPL(pci_pri_status);
 346 #endif /* CONFIG_PCI_PRI */
 347
 348 #ifdef CONFIG_PCI_PASID
 349 /**
 350  * pci_enable_pasid - Enable the PASID capability
 351  * @pdev: PCI device structure
 352  * @features: Features to enable
 353  *
 354  * Returns 0 on success, negative value on error. This function checks
 355  * whether the features are actually supported by the device and returns
 356  * an error if not.
 357  */
 358 int pci_enable_pasid(struct pci_dev *pdev, int features)
 359 {
 360         u16 control, supported;
 361         int pos;
 362
 363         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
 364         if (!pos)
 365                 return -EINVAL;
 366
 367         pci_read_config_word(pdev, pos + PCI_PASID_CTRL, &control);
 368         pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
 369
 370         if (control & PCI_PASID_CTRL_ENABLE)
 371                 return -EINVAL;
 372
 373         supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
 374
 375         /* User wants to enable anything unsupported? */
 376         if ((supported & features) != features)
 377                 return -EINVAL;
 378
 379         control = PCI_PASID_CTRL_ENABLE | features;
 380
 381         pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
 382
 383         return 0;
 384 }
 385 EXPORT_SYMBOL_GPL(pci_enable_pasid);
 386
 387 /**
 388  * pci_disable_pasid - Disable the PASID capability
 389  * @pdev: PCI device structure
 390  *
 391  */
 392 void pci_disable_pasid(struct pci_dev *pdev)
 393 {
 394         u16 control = 0;
 395         int pos;
 396
 397         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
 398         if (!pos)
 399                 return;
 400
 401         pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
 402 }
 403 EXPORT_SYMBOL_GPL(pci_disable_pasid);
 404
 405 /**
 406  * pci_pasid_features - Check which PASID features are supported
 407  * @pdev: PCI device structure
 408  *
 409  * Returns a negative value when no PASI capability is present.
 410  * Otherwise is returns a bitmask with supported features. Current
 411  * features reported are:
 412  * PCI_PASID_CAP_EXEC - Execute permission supported
 413  * PCI_PASID_CAP_PRIV - Priviledged mode supported
 414  */
 415 int pci_pasid_features(struct pci_dev *pdev)
 416 {
 417         u16 supported;
 418         int pos;
 419
 420         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
 421         if (!pos)
 422                 return -EINVAL;
 423
 424         pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
 425
 426         supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
 427
 428         return supported;
 429 }
 430 EXPORT_SYMBOL_GPL(pci_pasid_features);
 431
 432 #define PASID_NUMBER_SHIFT      8
 433 #define PASID_NUMBER_MASK       (0x1f << PASID_NUMBER_SHIFT)
 434 /**
 435  * pci_max_pasid - Get maximum number of PASIDs supported by device
 436  * @pdev: PCI device structure
 437  *
 438  * Returns negative value when PASID capability is not present.
 439  * Otherwise it returns the numer of supported PASIDs.
 440  */
 441 int pci_max_pasids(struct pci_dev *pdev)
 442 {
 443         u16 supported;
 444         int pos;
 445
 446         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
 447         if (!pos)
 448                 return -EINVAL;
 449
 450         pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
 451
 452         supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT;
 453
 454         return (1 << supported);
 455 }
 456 EXPORT_SYMBOL_GPL(pci_max_pasids);
 457 #endif /* CONFIG_PCI_PASID */