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 /**
 132  * pci_ats_queue_depth - query the ATS Invalidate Queue Depth
 133  * @dev: the PCI device
 134  *
 135  * Returns the queue depth on success, or negative on failure.
 136  *
 137  * The ATS spec uses 0 in the Invalidate Queue Depth field to
 138  * indicate that the function can accept 32 Invalidate Request.
 139  * But here we use the `real' values (i.e. 1~32) for the Queue
 140  * Depth; and 0 indicates the function shares the Queue with
 141  * other functions (doesn't exclusively own a Queue).
 142  */
 143 int pci_ats_queue_depth(struct pci_dev *dev)
 144 {
 145         int pos;
 146         u16 cap;
 147
 148         if (dev->is_virtfn)
 149                 return 0;
 150
 151         if (dev->ats)
 152                 return dev->ats->qdep;
 153
 154         pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
 155         if (!pos)
 156                 return -ENODEV;
 157
 158         pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
 159
 160         return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
 161                                        PCI_ATS_MAX_QDEP;
 162 }
 163 EXPORT_SYMBOL_GPL(pci_ats_queue_depth);
 164
 165 #ifdef CONFIG_PCI_PRI
 166 /**
 167  * pci_enable_pri - Enable PRI capability
 168  * @ pdev: PCI device structure
 169  *
 170  * Returns 0 on success, negative value on error
 171  */
 172 int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
 173 {
 174         u16 control, status;
 175         u32 max_requests;
 176         int pos;
 177
 178         pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
 179         if (!pos)
 180                 return -EINVAL;
 181
 182         pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
 183         pci_read_config_word(pdev, pos + PCI_PRI_STATUS_OFF,  &status);
 184         if ((control & PCI_PRI_ENABLE) || !(status & PCI_PRI_STATUS_STOPPED))
 185                 return -EBUSY;
 186
 187         pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ_OFF, &max_requests);
 188         reqs = min(max_requests, reqs);
 189         pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ_OFF, reqs);
 190
 191         control |= PCI_PRI_ENABLE;
 192         pci_write_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, control);
 193
 194         return 0;
 195 }
 196 EXPORT_SYMBOL_GPL(pci_enable_pri);
 197
 198 /**
 199  * pci_disable_pri - Disable PRI capability
 200  * @pdev: PCI device structure
 201  *
 202  * Only clears the enabled-bit, regardless of its former value
 203  */
 204 void pci_disable_pri(struct pci_dev *pdev)
 205 {
 206         u16 control;
 207         int pos;
 208
 209         pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
 210         if (!pos)
 211                 return;
 212
 213         pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
 214         control &= ~PCI_PRI_ENABLE;
 215         pci_write_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, control);
 216 }
 217 EXPORT_SYMBOL_GPL(pci_disable_pri);
 218
 219 /**
 220  * pci_pri_enabled - Checks if PRI capability is enabled
 221  * @pdev: PCI device structure
 222  *
 223  * Returns true if PRI is enabled on the device, false otherwise
 224  */
 225 bool pci_pri_enabled(struct pci_dev *pdev)
 226 {
 227         u16 control;
 228         int pos;
 229
 230         pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
 231         if (!pos)
 232                 return false;
 233
 234         pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
 235
 236         return (control & PCI_PRI_ENABLE) ? true : false;
 237 }
 238 EXPORT_SYMBOL_GPL(pci_pri_enabled);
 239
 240 /**
 241  * pci_reset_pri - Resets device's PRI state
 242  * @pdev: PCI device structure
 243  *
 244  * The PRI capability must be disabled before this function is called.
 245  * Returns 0 on success, negative value on error.
 246  */
 247 int pci_reset_pri(struct pci_dev *pdev)
 248 {
 249         u16 control;
 250         int pos;
 251
 252         pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
 253         if (!pos)
 254                 return -EINVAL;
 255
 256         pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
 257         if (control & PCI_PRI_ENABLE)
 258                 return -EBUSY;
 259
 260         control |= PCI_PRI_RESET;
 261
 262         pci_write_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, control);
 263
 264         return 0;
 265 }
 266 EXPORT_SYMBOL_GPL(pci_reset_pri);
 267
 268 /**
 269  * pci_pri_stopped - Checks whether the PRI capability is stopped
 270  * @pdev: PCI device structure
 271  *
 272  * Returns true if the PRI capability on the device is disabled and the
 273  * device has no outstanding PRI requests, false otherwise. The device
 274  * indicates this via the STOPPED bit in the status register of the
 275  * capability.
 276  * The device internal state can be cleared by resetting the PRI state
 277  * with pci_reset_pri(). This can force the capability into the STOPPED
 278  * state.
 279  */
 280 bool pci_pri_stopped(struct pci_dev *pdev)
 281 {
 282         u16 control, status;
 283         int pos;
 284
 285         pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
 286         if (!pos)
 287                 return true;
 288
 289         pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
 290         pci_read_config_word(pdev, pos + PCI_PRI_STATUS_OFF,  &status);
 291
 292         if (control & PCI_PRI_ENABLE)
 293                 return false;
 294
 295         return (status & PCI_PRI_STATUS_STOPPED) ? true : false;
 296 }
 297 EXPORT_SYMBOL_GPL(pci_pri_stopped);
 298
 299 /**
 300  * pci_pri_status - Request PRI status of a device
 301  * @pdev: PCI device structure
 302  *
 303  * Returns negative value on failure, status on success. The status can
 304  * be checked against status-bits. Supported bits are currently:
 305  * PCI_PRI_STATUS_RF:      Response failure
 306  * PCI_PRI_STATUS_UPRGI:   Unexpected Page Request Group Index
 307  * PCI_PRI_STATUS_STOPPED: PRI has stopped
 308  */
 309 int pci_pri_status(struct pci_dev *pdev)
 310 {
 311         u16 status, control;
 312         int pos;
 313
 314         pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
 315         if (!pos)
 316                 return -EINVAL;
 317
 318         pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
 319         pci_read_config_word(pdev, pos + PCI_PRI_STATUS_OFF,  &status);
 320
 321         /* Stopped bit is undefined when enable == 1, so clear it */
 322         if (control & PCI_PRI_ENABLE)
 323                 status &= ~PCI_PRI_STATUS_STOPPED;
 324
 325         return status;
 326 }
 327 EXPORT_SYMBOL_GPL(pci_pri_status);
 328 #endif /* CONFIG_PCI_PRI */
 329
 330 #ifdef CONFIG_PCI_PASID
 331 /**
 332  * pci_enable_pasid - Enable the PASID capability
 333  * @pdev: PCI device structure
 334  * @features: Features to enable
 335  *
 336  * Returns 0 on success, negative value on error. This function checks
 337  * whether the features are actually supported by the device and returns
 338  * an error if not.
 339  */
 340 int pci_enable_pasid(struct pci_dev *pdev, int features)
 341 {
 342         u16 control, supported;
 343         int pos;
 344
 345         pos = pci_find_ext_capability(pdev, PCI_PASID_CAP);
 346         if (!pos)
 347                 return -EINVAL;
 348
 349         pci_read_config_word(pdev, pos + PCI_PASID_CONTROL_OFF, &control);
 350         pci_read_config_word(pdev, pos + PCI_PASID_CAP_OFF,     &supported);
 351
 352         if (!(supported & PCI_PASID_ENABLE))
 353                 return -EINVAL;
 354
 355         supported &= PCI_PASID_EXEC | PCI_PASID_PRIV;
 356
 357         /* User wants to enable anything unsupported? */
 358         if ((supported & features) != features)
 359                 return -EINVAL;
 360
 361         control = PCI_PASID_ENABLE | features;
 362
 363         pci_write_config_word(pdev, pos + PCI_PASID_CONTROL_OFF, control);
 364
 365         return 0;
 366 }
 367 EXPORT_SYMBOL_GPL(pci_enable_pasid);
 368
 369 /**
 370  * pci_disable_pasid - Disable the PASID capability
 371  * @pdev: PCI device structure
 372  *
 373  */
 374 void pci_disable_pasid(struct pci_dev *pdev)
 375 {
 376         u16 control = 0;
 377         int pos;
 378
 379         pos = pci_find_ext_capability(pdev, PCI_PASID_CAP);
 380         if (!pos)
 381                 return;
 382
 383         pci_write_config_word(pdev, pos + PCI_PASID_CONTROL_OFF, control);
 384 }
 385 EXPORT_SYMBOL_GPL(pci_disable_pasid);
 386
 387 /**
 388  * pci_pasid_features - Check which PASID features are supported
 389  * @pdev: PCI device structure
 390  *
 391  * Returns a negative value when no PASI capability is present.
 392  * Otherwise is returns a bitmask with supported features. Current
 393  * features reported are:
 394  * PCI_PASID_ENABLE - PASID capability can be enabled
 395  * PCI_PASID_EXEC - Execute permission supported
 396  * PCI_PASID_PRIV - Priviledged mode supported
 397  */
 398 int pci_pasid_features(struct pci_dev *pdev)
 399 {
 400         u16 supported;
 401         int pos;
 402
 403         pos = pci_find_ext_capability(pdev, PCI_PASID_CAP);
 404         if (!pos)
 405                 return -EINVAL;
 406
 407         pci_read_config_word(pdev, pos + PCI_PASID_CAP_OFF, &supported);
 408
 409         supported &= PCI_PASID_ENABLE | PCI_PASID_EXEC | PCI_PASID_PRIV;
 410
 411         return supported;
 412 }
 413 EXPORT_SYMBOL_GPL(pci_pasid_features);
 414
 415 #define PASID_NUMBER_SHIFT      8
 416 #define PASID_NUMBER_MASK       (0x1f << PASID_NUMBER_SHIFT)
 417 /**
 418  * pci_max_pasid - Get maximum number of PASIDs supported by device
 419  * @pdev: PCI device structure
 420  *
 421  * Returns negative value when PASID capability is not present.
 422  * Otherwise it returns the numer of supported PASIDs.
 423  */
 424 int pci_max_pasids(struct pci_dev *pdev)
 425 {
 426         u16 supported;
 427         int pos;
 428
 429         pos = pci_find_ext_capability(pdev, PCI_PASID_CAP);
 430         if (!pos)
 431                 return -EINVAL;
 432
 433         pci_read_config_word(pdev, pos + PCI_PASID_CAP_OFF, &supported);
 434
 435         supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT;
 436
 437         return (1 << supported);
 438 }
 439 EXPORT_SYMBOL_GPL(pci_max_pasids);
 440 #endif /* CONFIG_PCI_PASID */