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 void pci_ats_init(struct pci_dev *dev)
  21 {
  22         int pos;
  23
  24         pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
  25         if (!pos)
  26                 return;
  27
  28         dev->ats_cap = pos;
  29 }
  30
  31 /**
  32  * pci_enable_ats - enable the ATS capability
  33  * @dev: the PCI device
  34  * @ps: the IOMMU page shift
  35  *
  36  * Returns 0 on success, or negative on failure.
  37  */
  38 int pci_enable_ats(struct pci_dev *dev, int ps)
  39 {
  40         u16 ctrl;
  41         struct pci_dev *pdev;
  42
  43         if (!dev->ats_cap)
  44                 return -EINVAL;
  45
  46         if (WARN_ON(dev->ats_enabled))
  47                 return -EBUSY;
  48
  49         if (ps < PCI_ATS_MIN_STU)
  50                 return -EINVAL;
  51
  52         /*
  53          * Note that enabling ATS on a VF fails unless it's already enabled
  54          * with the same STU on the PF.
  55          */
  56         ctrl = PCI_ATS_CTRL_ENABLE;
  57         if (dev->is_virtfn) {
  58                 pdev = pci_physfn(dev);
  59                 if (pdev->ats_stu != ps)
  60                         return -EINVAL;
  61
  62                 atomic_inc(&pdev->ats_ref_cnt);  /* count enabled VFs */
  63         } else {
  64                 dev->ats_stu = ps;
  65                 ctrl |= PCI_ATS_CTRL_STU(dev->ats_stu - PCI_ATS_MIN_STU);
  66         }
  67         pci_write_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, ctrl);
  68
  69         dev->ats_enabled = 1;
  70         return 0;
  71 }
  72 EXPORT_SYMBOL_GPL(pci_enable_ats);
  73
  74 /**
  75  * pci_disable_ats - disable the ATS capability
  76  * @dev: the PCI device
  77  */
  78 void pci_disable_ats(struct pci_dev *dev)
  79 {
  80         struct pci_dev *pdev;
  81         u16 ctrl;
  82
  83         if (WARN_ON(!dev->ats_enabled))
  84                 return;
  85
  86         if (atomic_read(&dev->ats_ref_cnt))
  87                 return;         /* VFs still enabled */
  88
  89         if (dev->is_virtfn) {
  90                 pdev = pci_physfn(dev);
  91                 atomic_dec(&pdev->ats_ref_cnt);
  92         }
  93
  94         pci_read_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, &ctrl);
  95         ctrl &= ~PCI_ATS_CTRL_ENABLE;
  96         pci_write_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, ctrl);
  97
  98         dev->ats_enabled = 0;
  99 }
 100 EXPORT_SYMBOL_GPL(pci_disable_ats);
 101
 102 void pci_restore_ats_state(struct pci_dev *dev)
 103 {
 104         u16 ctrl;
 105
 106         if (!dev->ats_enabled)
 107                 return;
 108
 109         ctrl = PCI_ATS_CTRL_ENABLE;
 110         if (!dev->is_virtfn)
 111                 ctrl |= PCI_ATS_CTRL_STU(dev->ats_stu - PCI_ATS_MIN_STU);
 112         pci_write_config_word(dev, dev->ats_cap + PCI_ATS_CTRL, ctrl);
 113 }
 114 EXPORT_SYMBOL_GPL(pci_restore_ats_state);
 115
 116 /**
 117  * pci_ats_queue_depth - query the ATS Invalidate Queue Depth
 118  * @dev: the PCI device
 119  *
 120  * Returns the queue depth on success, or negative on failure.
 121  *
 122  * The ATS spec uses 0 in the Invalidate Queue Depth field to
 123  * indicate that the function can accept 32 Invalidate Request.
 124  * But here we use the `real' values (i.e. 1~32) for the Queue
 125  * Depth; and 0 indicates the function shares the Queue with
 126  * other functions (doesn't exclusively own a Queue).
 127  */
 128 int pci_ats_queue_depth(struct pci_dev *dev)
 129 {
 130         u16 cap;
 131
 132         if (!dev->ats_cap)
 133                 return -EINVAL;
 134
 135         if (dev->is_virtfn)
 136                 return 0;
 137
 138         pci_read_config_word(dev, dev->ats_cap + PCI_ATS_CAP, &cap);
 139         return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) : PCI_ATS_MAX_QDEP;
 140 }
 141 EXPORT_SYMBOL_GPL(pci_ats_queue_depth);
 142
 143 #ifdef CONFIG_PCI_PRI
 144 /**
 145  * pci_enable_pri - Enable PRI capability
 146  * @ pdev: PCI device structure
 147  *
 148  * Returns 0 on success, negative value on error
 149  */
 150 int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
 151 {
 152         u16 control, status;
 153         u32 max_requests;
 154         int pos;
 155
 156         if (WARN_ON(pdev->pri_enabled))
 157                 return -EBUSY;
 158
 159         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
 160         if (!pos)
 161                 return -EINVAL;
 162
 163         pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
 164         if (!(status & PCI_PRI_STATUS_STOPPED))
 165                 return -EBUSY;
 166
 167         pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ, &max_requests);
 168         reqs = min(max_requests, reqs);
 169         pdev->pri_reqs_alloc = reqs;
 170         pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
 171
 172         control = PCI_PRI_CTRL_ENABLE;
 173         pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
 174
 175         pdev->pri_enabled = 1;
 176
 177         return 0;
 178 }
 179 EXPORT_SYMBOL_GPL(pci_enable_pri);
 180
 181 /**
 182  * pci_disable_pri - Disable PRI capability
 183  * @pdev: PCI device structure
 184  *
 185  * Only clears the enabled-bit, regardless of its former value
 186  */
 187 void pci_disable_pri(struct pci_dev *pdev)
 188 {
 189         u16 control;
 190         int pos;
 191
 192         if (WARN_ON(!pdev->pri_enabled))
 193                 return;
 194
 195         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
 196         if (!pos)
 197                 return;
 198
 199         pci_read_config_word(pdev, pos + PCI_PRI_CTRL, &control);
 200         control &= ~PCI_PRI_CTRL_ENABLE;
 201         pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
 202
 203         pdev->pri_enabled = 0;
 204 }
 205 EXPORT_SYMBOL_GPL(pci_disable_pri);
 206
 207 /**
 208  * pci_restore_pri_state - Restore PRI
 209  * @pdev: PCI device structure
 210  */
 211 void pci_restore_pri_state(struct pci_dev *pdev)
 212 {
 213         u16 control = PCI_PRI_CTRL_ENABLE;
 214         u32 reqs = pdev->pri_reqs_alloc;
 215         int pos;
 216
 217         if (!pdev->pri_enabled)
 218                 return;
 219
 220         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
 221         if (!pos)
 222                 return;
 223
 224         pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ, reqs);
 225         pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
 226 }
 227 EXPORT_SYMBOL_GPL(pci_restore_pri_state);
 228
 229 /**
 230  * pci_reset_pri - Resets device's PRI state
 231  * @pdev: PCI device structure
 232  *
 233  * The PRI capability must be disabled before this function is called.
 234  * Returns 0 on success, negative value on error.
 235  */
 236 int pci_reset_pri(struct pci_dev *pdev)
 237 {
 238         u16 control;
 239         int pos;
 240
 241         if (WARN_ON(pdev->pri_enabled))
 242                 return -EBUSY;
 243
 244         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
 245         if (!pos)
 246                 return -EINVAL;
 247
 248         control = PCI_PRI_CTRL_RESET;
 249         pci_write_config_word(pdev, pos + PCI_PRI_CTRL, control);
 250
 251         return 0;
 252 }
 253 EXPORT_SYMBOL_GPL(pci_reset_pri);
 254 #endif /* CONFIG_PCI_PRI */
 255
 256 #ifdef CONFIG_PCI_PASID
 257 /**
 258  * pci_enable_pasid - Enable the PASID capability
 259  * @pdev: PCI device structure
 260  * @features: Features to enable
 261  *
 262  * Returns 0 on success, negative value on error. This function checks
 263  * whether the features are actually supported by the device and returns
 264  * an error if not.
 265  */
 266 int pci_enable_pasid(struct pci_dev *pdev, int features)
 267 {
 268         u16 control, supported;
 269         int pos;
 270
 271         if (WARN_ON(pdev->pasid_enabled))
 272                 return -EBUSY;
 273
 274         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
 275         if (!pos)
 276                 return -EINVAL;
 277
 278         pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
 279         supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
 280
 281         /* User wants to enable anything unsupported? */
 282         if ((supported & features) != features)
 283                 return -EINVAL;
 284
 285         control = PCI_PASID_CTRL_ENABLE | features;
 286         pdev->pasid_features = features;
 287
 288         pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
 289
 290         pdev->pasid_enabled = 1;
 291
 292         return 0;
 293 }
 294 EXPORT_SYMBOL_GPL(pci_enable_pasid);
 295
 296 /**
 297  * pci_disable_pasid - Disable the PASID capability
 298  * @pdev: PCI device structure
 299  */
 300 void pci_disable_pasid(struct pci_dev *pdev)
 301 {
 302         u16 control = 0;
 303         int pos;
 304
 305         if (WARN_ON(!pdev->pasid_enabled))
 306                 return;
 307
 308         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
 309         if (!pos)
 310                 return;
 311
 312         pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
 313
 314         pdev->pasid_enabled = 0;
 315 }
 316 EXPORT_SYMBOL_GPL(pci_disable_pasid);
 317
 318 /**
 319  * pci_restore_pasid_state - Restore PASID capabilities
 320  * @pdev: PCI device structure
 321  */
 322 void pci_restore_pasid_state(struct pci_dev *pdev)
 323 {
 324         u16 control;
 325         int pos;
 326
 327         if (!pdev->pasid_enabled)
 328                 return;
 329
 330         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
 331         if (!pos)
 332                 return;
 333
 334         control = PCI_PASID_CTRL_ENABLE | pdev->pasid_features;
 335         pci_write_config_word(pdev, pos + PCI_PASID_CTRL, control);
 336 }
 337 EXPORT_SYMBOL_GPL(pci_restore_pasid_state);
 338
 339 /**
 340  * pci_pasid_features - Check which PASID features are supported
 341  * @pdev: PCI device structure
 342  *
 343  * Returns a negative value when no PASI capability is present.
 344  * Otherwise is returns a bitmask with supported features. Current
 345  * features reported are:
 346  * PCI_PASID_CAP_EXEC - Execute permission supported
 347  * PCI_PASID_CAP_PRIV - Privileged mode supported
 348  */
 349 int pci_pasid_features(struct pci_dev *pdev)
 350 {
 351         u16 supported;
 352         int pos;
 353
 354         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
 355         if (!pos)
 356                 return -EINVAL;
 357
 358         pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
 359
 360         supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
 361
 362         return supported;
 363 }
 364 EXPORT_SYMBOL_GPL(pci_pasid_features);
 365
 366 #define PASID_NUMBER_SHIFT      8
 367 #define PASID_NUMBER_MASK       (0x1f << PASID_NUMBER_SHIFT)
 368 /**
 369  * pci_max_pasid - Get maximum number of PASIDs supported by device
 370  * @pdev: PCI device structure
 371  *
 372  * Returns negative value when PASID capability is not present.
 373  * Otherwise it returns the numer of supported PASIDs.
 374  */
 375 int pci_max_pasids(struct pci_dev *pdev)
 376 {
 377         u16 supported;
 378         int pos;
 379
 380         pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID);
 381         if (!pos)
 382                 return -EINVAL;
 383
 384         pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported);
 385
 386         supported = (supported & PASID_NUMBER_MASK) >> PASID_NUMBER_SHIFT;
 387
 388         return (1 << supported);
 389 }
 390 EXPORT_SYMBOL_GPL(pci_max_pasids);
 391 #endif /* CONFIG_PCI_PASID */