drivers/dma/ioat/dca.c

   1 /*
   2  * Intel I/OAT DMA Linux driver
   3  * Copyright(c) 2007 - 2009 Intel Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   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.,
  16  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * The full GNU General Public License is included in this distribution in
  19  * the file called "COPYING".
  20  *
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/pci.h>
  25 #include <linux/smp.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/dca.h>
  28
  29 /* either a kernel change is needed, or we need something like this in kernel */
  30 #ifndef CONFIG_SMP
  31 #include <asm/smp.h>
  32 #undef cpu_physical_id
  33 #define cpu_physical_id(cpu) (cpuid_ebx(1) >> 24)
  34 #endif
  35
  36 #include "dma.h"
  37 #include "registers.h"
  38 #include "dma_v2.h"
  39
  40 /*
  41  * Bit 7 of a tag map entry is the "valid" bit, if it is set then bits 0:6
  42  * contain the bit number of the APIC ID to map into the DCA tag.  If the valid
  43  * bit is not set, then the value must be 0 or 1 and defines the bit in the tag.
  44  */
  45 #define DCA_TAG_MAP_VALID 0x80
  46
  47 #define DCA3_TAG_MAP_BIT_TO_INV 0x80
  48 #define DCA3_TAG_MAP_BIT_TO_SEL 0x40
  49 #define DCA3_TAG_MAP_LITERAL_VAL 0x1
  50
  51 #define DCA_TAG_MAP_MASK 0xDF
  52
  53 /* expected tag map bytes for I/OAT ver.2 */
  54 #define DCA2_TAG_MAP_BYTE0 0x80
  55 #define DCA2_TAG_MAP_BYTE1 0x0
  56 #define DCA2_TAG_MAP_BYTE2 0x81
  57 #define DCA2_TAG_MAP_BYTE3 0x82
  58 #define DCA2_TAG_MAP_BYTE4 0x82
  59
  60 /* verify if tag map matches expected values */
  61 static inline int dca2_tag_map_valid(u8 *tag_map)
  62 {
  63         return ((tag_map[0] == DCA2_TAG_MAP_BYTE0) &&
  64                 (tag_map[1] == DCA2_TAG_MAP_BYTE1) &&
  65                 (tag_map[2] == DCA2_TAG_MAP_BYTE2) &&
  66                 (tag_map[3] == DCA2_TAG_MAP_BYTE3) &&
  67                 (tag_map[4] == DCA2_TAG_MAP_BYTE4));
  68 }
  69
  70 /*
  71  * "Legacy" DCA systems do not implement the DCA register set in the
  72  * I/OAT device.  Software needs direct support for their tag mappings.
  73  */
  74
  75 #define APICID_BIT(x)           (DCA_TAG_MAP_VALID | (x))
  76 #define IOAT_TAG_MAP_LEN        8
  77
  78 static u8 ioat_tag_map_BNB[IOAT_TAG_MAP_LEN] = {
  79         1, APICID_BIT(1), APICID_BIT(2), APICID_BIT(2), };
  80 static u8 ioat_tag_map_SCNB[IOAT_TAG_MAP_LEN] = {
  81         1, APICID_BIT(1), APICID_BIT(2), APICID_BIT(2), };
  82 static u8 ioat_tag_map_CNB[IOAT_TAG_MAP_LEN] = {
  83         1, APICID_BIT(1), APICID_BIT(3), APICID_BIT(4), APICID_BIT(2), };
  84 static u8 ioat_tag_map_UNISYS[IOAT_TAG_MAP_LEN] = { 0 };
  85
  86 /* pack PCI B/D/F into a u16 */
  87 static inline u16 dcaid_from_pcidev(struct pci_dev *pci)
  88 {
  89         return (pci->bus->number << 8) | pci->devfn;
  90 }
  91
  92 static int dca_enabled_in_bios(struct pci_dev *pdev)
  93 {
  94         /* CPUID level 9 returns DCA configuration */
  95         /* Bit 0 indicates DCA enabled by the BIOS */
  96         unsigned long cpuid_level_9;
  97         int res;
  98
  99         cpuid_level_9 = cpuid_eax(9);
 100         res = test_bit(0, &cpuid_level_9);
 101         if (!res)
 102                 dev_dbg(&pdev->dev, "DCA is disabled in BIOS\n");
 103
 104         return res;
 105 }
 106
 107 int system_has_dca_enabled(struct pci_dev *pdev)
 108 {
 109         if (boot_cpu_has(X86_FEATURE_DCA))
 110                 return dca_enabled_in_bios(pdev);
 111
 112         dev_dbg(&pdev->dev, "boot cpu doesn't have X86_FEATURE_DCA\n");
 113         return 0;
 114 }
 115
 116 struct ioat_dca_slot {
 117         struct pci_dev *pdev;   /* requester device */
 118         u16 rid;                /* requester id, as used by IOAT */
 119 };
 120
 121 #define IOAT_DCA_MAX_REQ 6
 122 #define IOAT3_DCA_MAX_REQ 2
 123
 124 struct ioat_dca_priv {
 125         void __iomem            *iobase;
 126         void __iomem            *dca_base;
 127         int                      max_requesters;
 128         int                      requester_count;
 129         u8                       tag_map[IOAT_TAG_MAP_LEN];
 130         struct ioat_dca_slot     req_slots[0];
 131 };
 132
 133 /* 5000 series chipset DCA Port Requester ID Table Entry Format
 134  * [15:8]       PCI-Express Bus Number
 135  * [7:3]        PCI-Express Device Number
 136  * [2:0]        PCI-Express Function Number
 137  *
 138  * 5000 series chipset DCA control register format
 139  * [7:1]        Reserved (0)
 140  * [0]          Ignore Function Number
 141  */
 142
 143 static int ioat_dca_add_requester(struct dca_provider *dca, struct device *dev)
 144 {
 145         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 146         struct pci_dev *pdev;
 147         int i;
 148         u16 id;
 149
 150         /* This implementation only supports PCI-Express */
 151         if (!dev_is_pci(dev))
 152                 return -ENODEV;
 153         pdev = to_pci_dev(dev);
 154         id = dcaid_from_pcidev(pdev);
 155
 156         if (ioatdca->requester_count == ioatdca->max_requesters)
 157                 return -ENODEV;
 158
 159         for (i = 0; i < ioatdca->max_requesters; i++) {
 160                 if (ioatdca->req_slots[i].pdev == NULL) {
 161                         /* found an empty slot */
 162                         ioatdca->requester_count++;
 163                         ioatdca->req_slots[i].pdev = pdev;
 164                         ioatdca->req_slots[i].rid = id;
 165                         writew(id, ioatdca->dca_base + (i * 4));
 166                         /* make sure the ignore function bit is off */
 167                         writeb(0, ioatdca->dca_base + (i * 4) + 2);
 168                         return i;
 169                 }
 170         }
 171         /* Error, ioatdma->requester_count is out of whack */
 172         return -EFAULT;
 173 }
 174
 175 static int ioat_dca_remove_requester(struct dca_provider *dca,
 176                                      struct device *dev)
 177 {
 178         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 179         struct pci_dev *pdev;
 180         int i;
 181
 182         /* This implementation only supports PCI-Express */
 183         if (!dev_is_pci(dev))
 184                 return -ENODEV;
 185         pdev = to_pci_dev(dev);
 186
 187         for (i = 0; i < ioatdca->max_requesters; i++) {
 188                 if (ioatdca->req_slots[i].pdev == pdev) {
 189                         writew(0, ioatdca->dca_base + (i * 4));
 190                         ioatdca->req_slots[i].pdev = NULL;
 191                         ioatdca->req_slots[i].rid = 0;
 192                         ioatdca->requester_count--;
 193                         return i;
 194                 }
 195         }
 196         return -ENODEV;
 197 }
 198
 199 static u8 ioat_dca_get_tag(struct dca_provider *dca,
 200                            struct device *dev,
 201                            int cpu)
 202 {
 203         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 204         int i, apic_id, bit, value;
 205         u8 entry, tag;
 206
 207         tag = 0;
 208         apic_id = cpu_physical_id(cpu);
 209
 210         for (i = 0; i < IOAT_TAG_MAP_LEN; i++) {
 211                 entry = ioatdca->tag_map[i];
 212                 if (entry & DCA_TAG_MAP_VALID) {
 213                         bit = entry & ~DCA_TAG_MAP_VALID;
 214                         value = (apic_id & (1 << bit)) ? 1 : 0;
 215                 } else {
 216                         value = entry ? 1 : 0;
 217                 }
 218                 tag |= (value << i);
 219         }
 220         return tag;
 221 }
 222
 223 static int ioat_dca_dev_managed(struct dca_provider *dca,
 224                                 struct device *dev)
 225 {
 226         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 227         struct pci_dev *pdev;
 228         int i;
 229
 230         pdev = to_pci_dev(dev);
 231         for (i = 0; i < ioatdca->max_requesters; i++) {
 232                 if (ioatdca->req_slots[i].pdev == pdev)
 233                         return 1;
 234         }
 235         return 0;
 236 }
 237
 238 static struct dca_ops ioat_dca_ops = {
 239         .add_requester          = ioat_dca_add_requester,
 240         .remove_requester       = ioat_dca_remove_requester,
 241         .get_tag                = ioat_dca_get_tag,
 242         .dev_managed            = ioat_dca_dev_managed,
 243 };
 244
 245
 246 struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
 247 {
 248         struct dca_provider *dca;
 249         struct ioat_dca_priv *ioatdca;
 250         u8 *tag_map = NULL;
 251         int i;
 252         int err;
 253         u8 version;
 254         u8 max_requesters;
 255
 256         if (!system_has_dca_enabled(pdev))
 257                 return NULL;
 258
 259         /* I/OAT v1 systems must have a known tag_map to support DCA */
 260         switch (pdev->vendor) {
 261         case PCI_VENDOR_ID_INTEL:
 262                 switch (pdev->device) {
 263                 case PCI_DEVICE_ID_INTEL_IOAT:
 264                         tag_map = ioat_tag_map_BNB;
 265                         break;
 266                 case PCI_DEVICE_ID_INTEL_IOAT_CNB:
 267                         tag_map = ioat_tag_map_CNB;
 268                         break;
 269                 case PCI_DEVICE_ID_INTEL_IOAT_SCNB:
 270                         tag_map = ioat_tag_map_SCNB;
 271                         break;
 272                 }
 273                 break;
 274         case PCI_VENDOR_ID_UNISYS:
 275                 switch (pdev->device) {
 276                 case PCI_DEVICE_ID_UNISYS_DMA_DIRECTOR:
 277                         tag_map = ioat_tag_map_UNISYS;
 278                         break;
 279                 }
 280                 break;
 281         }
 282         if (tag_map == NULL)
 283                 return NULL;
 284
 285         version = readb(iobase + IOAT_VER_OFFSET);
 286         if (version == IOAT_VER_3_0)
 287                 max_requesters = IOAT3_DCA_MAX_REQ;
 288         else
 289                 max_requesters = IOAT_DCA_MAX_REQ;
 290
 291         dca = alloc_dca_provider(&ioat_dca_ops,
 292                         sizeof(*ioatdca) +
 293                         (sizeof(struct ioat_dca_slot) * max_requesters));
 294         if (!dca)
 295                 return NULL;
 296
 297         ioatdca = dca_priv(dca);
 298         ioatdca->max_requesters = max_requesters;
 299         ioatdca->dca_base = iobase + 0x54;
 300
 301         /* copy over the APIC ID to DCA tag mapping */
 302         for (i = 0; i < IOAT_TAG_MAP_LEN; i++)
 303                 ioatdca->tag_map[i] = tag_map[i];
 304
 305         err = register_dca_provider(dca, &pdev->dev);
 306         if (err) {
 307                 free_dca_provider(dca);
 308                 return NULL;
 309         }
 310
 311         return dca;
 312 }
 313
 314
 315 static int ioat2_dca_add_requester(struct dca_provider *dca, struct device *dev)
 316 {
 317         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 318         struct pci_dev *pdev;
 319         int i;
 320         u16 id;
 321         u16 global_req_table;
 322
 323         /* This implementation only supports PCI-Express */
 324         if (!dev_is_pci(dev))
 325                 return -ENODEV;
 326         pdev = to_pci_dev(dev);
 327         id = dcaid_from_pcidev(pdev);
 328
 329         if (ioatdca->requester_count == ioatdca->max_requesters)
 330                 return -ENODEV;
 331
 332         for (i = 0; i < ioatdca->max_requesters; i++) {
 333                 if (ioatdca->req_slots[i].pdev == NULL) {
 334                         /* found an empty slot */
 335                         ioatdca->requester_count++;
 336                         ioatdca->req_slots[i].pdev = pdev;
 337                         ioatdca->req_slots[i].rid = id;
 338                         global_req_table =
 339                               readw(ioatdca->dca_base + IOAT_DCA_GREQID_OFFSET);
 340                         writel(id | IOAT_DCA_GREQID_VALID,
 341                                ioatdca->iobase + global_req_table + (i * 4));
 342                         return i;
 343                 }
 344         }
 345         /* Error, ioatdma->requester_count is out of whack */
 346         return -EFAULT;
 347 }
 348
 349 static int ioat2_dca_remove_requester(struct dca_provider *dca,
 350                                       struct device *dev)
 351 {
 352         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 353         struct pci_dev *pdev;
 354         int i;
 355         u16 global_req_table;
 356
 357         /* This implementation only supports PCI-Express */
 358         if (!dev_is_pci(dev))
 359                 return -ENODEV;
 360         pdev = to_pci_dev(dev);
 361
 362         for (i = 0; i < ioatdca->max_requesters; i++) {
 363                 if (ioatdca->req_slots[i].pdev == pdev) {
 364                         global_req_table =
 365                               readw(ioatdca->dca_base + IOAT_DCA_GREQID_OFFSET);
 366                         writel(0, ioatdca->iobase + global_req_table + (i * 4));
 367                         ioatdca->req_slots[i].pdev = NULL;
 368                         ioatdca->req_slots[i].rid = 0;
 369                         ioatdca->requester_count--;
 370                         return i;
 371                 }
 372         }
 373         return -ENODEV;
 374 }
 375
 376 static u8 ioat2_dca_get_tag(struct dca_provider *dca,
 377                             struct device *dev,
 378                             int cpu)
 379 {
 380         u8 tag;
 381
 382         tag = ioat_dca_get_tag(dca, dev, cpu);
 383         tag = (~tag) & 0x1F;
 384         return tag;
 385 }
 386
 387 static struct dca_ops ioat2_dca_ops = {
 388         .add_requester          = ioat2_dca_add_requester,
 389         .remove_requester       = ioat2_dca_remove_requester,
 390         .get_tag                = ioat2_dca_get_tag,
 391         .dev_managed            = ioat_dca_dev_managed,
 392 };
 393
 394 static int ioat2_dca_count_dca_slots(void __iomem *iobase, u16 dca_offset)
 395 {
 396         int slots = 0;
 397         u32 req;
 398         u16 global_req_table;
 399
 400         global_req_table = readw(iobase + dca_offset + IOAT_DCA_GREQID_OFFSET);
 401         if (global_req_table == 0)
 402                 return 0;
 403         do {
 404                 req = readl(iobase + global_req_table + (slots * sizeof(u32)));
 405                 slots++;
 406         } while ((req & IOAT_DCA_GREQID_LASTID) == 0);
 407
 408         return slots;
 409 }
 410
 411 struct dca_provider *ioat2_dca_init(struct pci_dev *pdev, void __iomem *iobase)
 412 {
 413         struct dca_provider *dca;
 414         struct ioat_dca_priv *ioatdca;
 415         int slots;
 416         int i;
 417         int err;
 418         u32 tag_map;
 419         u16 dca_offset;
 420         u16 csi_fsb_control;
 421         u16 pcie_control;
 422         u8 bit;
 423
 424         if (!system_has_dca_enabled(pdev))
 425                 return NULL;
 426
 427         dca_offset = readw(iobase + IOAT_DCAOFFSET_OFFSET);
 428         if (dca_offset == 0)
 429                 return NULL;
 430
 431         slots = ioat2_dca_count_dca_slots(iobase, dca_offset);
 432         if (slots == 0)
 433                 return NULL;
 434
 435         dca = alloc_dca_provider(&ioat2_dca_ops,
 436                                  sizeof(*ioatdca)
 437                                       + (sizeof(struct ioat_dca_slot) * slots));
 438         if (!dca)
 439                 return NULL;
 440
 441         ioatdca = dca_priv(dca);
 442         ioatdca->iobase = iobase;
 443         ioatdca->dca_base = iobase + dca_offset;
 444         ioatdca->max_requesters = slots;
 445
 446         /* some bios might not know to turn these on */
 447         csi_fsb_control = readw(ioatdca->dca_base + IOAT_FSB_CAP_ENABLE_OFFSET);
 448         if ((csi_fsb_control & IOAT_FSB_CAP_ENABLE_PREFETCH) == 0) {
 449                 csi_fsb_control |= IOAT_FSB_CAP_ENABLE_PREFETCH;
 450                 writew(csi_fsb_control,
 451                        ioatdca->dca_base + IOAT_FSB_CAP_ENABLE_OFFSET);
 452         }
 453         pcie_control = readw(ioatdca->dca_base + IOAT_PCI_CAP_ENABLE_OFFSET);
 454         if ((pcie_control & IOAT_PCI_CAP_ENABLE_MEMWR) == 0) {
 455                 pcie_control |= IOAT_PCI_CAP_ENABLE_MEMWR;
 456                 writew(pcie_control,
 457                        ioatdca->dca_base + IOAT_PCI_CAP_ENABLE_OFFSET);
 458         }
 459
 460
 461         /* TODO version, compatibility and configuration checks */
 462
 463         /* copy out the APIC to DCA tag map */
 464         tag_map = readl(ioatdca->dca_base + IOAT_APICID_TAG_MAP_OFFSET);
 465         for (i = 0; i < 5; i++) {
 466                 bit = (tag_map >> (4 * i)) & 0x0f;
 467                 if (bit < 8)
 468                         ioatdca->tag_map[i] = bit | DCA_TAG_MAP_VALID;
 469                 else
 470                         ioatdca->tag_map[i] = 0;
 471         }
 472
 473         if (!dca2_tag_map_valid(ioatdca->tag_map)) {
 474                 WARN_TAINT_ONCE(1, TAINT_FIRMWARE_WORKAROUND,
 475                                 "%s %s: APICID_TAG_MAP set incorrectly by BIOS, disabling DCA\n",
 476                                 dev_driver_string(&pdev->dev),
 477                                 dev_name(&pdev->dev));
 478                 free_dca_provider(dca);
 479                 return NULL;
 480         }
 481
 482         err = register_dca_provider(dca, &pdev->dev);
 483         if (err) {
 484                 free_dca_provider(dca);
 485                 return NULL;
 486         }
 487
 488         return dca;
 489 }
 490
 491 static int ioat3_dca_add_requester(struct dca_provider *dca, struct device *dev)
 492 {
 493         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 494         struct pci_dev *pdev;
 495         int i;
 496         u16 id;
 497         u16 global_req_table;
 498
 499         /* This implementation only supports PCI-Express */
 500         if (!dev_is_pci(dev))
 501                 return -ENODEV;
 502         pdev = to_pci_dev(dev);
 503         id = dcaid_from_pcidev(pdev);
 504
 505         if (ioatdca->requester_count == ioatdca->max_requesters)
 506                 return -ENODEV;
 507
 508         for (i = 0; i < ioatdca->max_requesters; i++) {
 509                 if (ioatdca->req_slots[i].pdev == NULL) {
 510                         /* found an empty slot */
 511                         ioatdca->requester_count++;
 512                         ioatdca->req_slots[i].pdev = pdev;
 513                         ioatdca->req_slots[i].rid = id;
 514                         global_req_table =
 515                               readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
 516                         writel(id | IOAT_DCA_GREQID_VALID,
 517                                ioatdca->iobase + global_req_table + (i * 4));
 518                         return i;
 519                 }
 520         }
 521         /* Error, ioatdma->requester_count is out of whack */
 522         return -EFAULT;
 523 }
 524
 525 static int ioat3_dca_remove_requester(struct dca_provider *dca,
 526                                       struct device *dev)
 527 {
 528         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 529         struct pci_dev *pdev;
 530         int i;
 531         u16 global_req_table;
 532
 533         /* This implementation only supports PCI-Express */
 534         if (!dev_is_pci(dev))
 535                 return -ENODEV;
 536         pdev = to_pci_dev(dev);
 537
 538         for (i = 0; i < ioatdca->max_requesters; i++) {
 539                 if (ioatdca->req_slots[i].pdev == pdev) {
 540                         global_req_table =
 541                               readw(ioatdca->dca_base + IOAT3_DCA_GREQID_OFFSET);
 542                         writel(0, ioatdca->iobase + global_req_table + (i * 4));
 543                         ioatdca->req_slots[i].pdev = NULL;
 544                         ioatdca->req_slots[i].rid = 0;
 545                         ioatdca->requester_count--;
 546                         return i;
 547                 }
 548         }
 549         return -ENODEV;
 550 }
 551
 552 static u8 ioat3_dca_get_tag(struct dca_provider *dca,
 553                             struct device *dev,
 554                             int cpu)
 555 {
 556         u8 tag;
 557
 558         struct ioat_dca_priv *ioatdca = dca_priv(dca);
 559         int i, apic_id, bit, value;
 560         u8 entry;
 561
 562         tag = 0;
 563         apic_id = cpu_physical_id(cpu);
 564
 565         for (i = 0; i < IOAT_TAG_MAP_LEN; i++) {
 566                 entry = ioatdca->tag_map[i];
 567                 if (entry & DCA3_TAG_MAP_BIT_TO_SEL) {
 568                         bit = entry &
 569                                 ~(DCA3_TAG_MAP_BIT_TO_SEL | DCA3_TAG_MAP_BIT_TO_INV);
 570                         value = (apic_id & (1 << bit)) ? 1 : 0;
 571                 } else if (entry & DCA3_TAG_MAP_BIT_TO_INV) {
 572                         bit = entry & ~DCA3_TAG_MAP_BIT_TO_INV;
 573                         value = (apic_id & (1 << bit)) ? 0 : 1;
 574                 } else {
 575                         value = (entry & DCA3_TAG_MAP_LITERAL_VAL) ? 1 : 0;
 576                 }
 577                 tag |= (value << i);
 578         }
 579
 580         return tag;
 581 }
 582
 583 static struct dca_ops ioat3_dca_ops = {
 584         .add_requester          = ioat3_dca_add_requester,
 585         .remove_requester       = ioat3_dca_remove_requester,
 586         .get_tag                = ioat3_dca_get_tag,
 587         .dev_managed            = ioat_dca_dev_managed,
 588 };
 589
 590 static int ioat3_dca_count_dca_slots(void *iobase, u16 dca_offset)
 591 {
 592         int slots = 0;
 593         u32 req;
 594         u16 global_req_table;
 595
 596         global_req_table = readw(iobase + dca_offset + IOAT3_DCA_GREQID_OFFSET);
 597         if (global_req_table == 0)
 598                 return 0;
 599
 600         do {
 601                 req = readl(iobase + global_req_table + (slots * sizeof(u32)));
 602                 slots++;
 603         } while ((req & IOAT_DCA_GREQID_LASTID) == 0);
 604
 605         return slots;
 606 }
 607
 608 static inline int dca3_tag_map_invalid(u8 *tag_map)
 609 {
 610         /*
 611          * If the tag map is not programmed by the BIOS the default is:
 612          * 0x80 0x80 0x80 0x80 0x80 0x00 0x00 0x00
 613          *
 614          * This an invalid map and will result in only 2 possible tags
 615          * 0x1F and 0x00.  0x00 is an invalid DCA tag so we know that
 616          * this entire definition is invalid.
 617          */
 618         return ((tag_map[0] == DCA_TAG_MAP_VALID) &&
 619                 (tag_map[1] == DCA_TAG_MAP_VALID) &&
 620                 (tag_map[2] == DCA_TAG_MAP_VALID) &&
 621                 (tag_map[3] == DCA_TAG_MAP_VALID) &&
 622                 (tag_map[4] == DCA_TAG_MAP_VALID));
 623 }
 624
 625 struct dca_provider *ioat3_dca_init(struct pci_dev *pdev, void __iomem *iobase)
 626 {
 627         struct dca_provider *dca;
 628         struct ioat_dca_priv *ioatdca;
 629         int slots;
 630         int i;
 631         int err;
 632         u16 dca_offset;
 633         u16 csi_fsb_control;
 634         u16 pcie_control;
 635         u8 bit;
 636
 637         union {
 638                 u64 full;
 639                 struct {
 640                         u32 low;
 641                         u32 high;
 642                 };
 643         } tag_map;
 644
 645         if (!system_has_dca_enabled(pdev))
 646                 return NULL;
 647
 648         dca_offset = readw(iobase + IOAT_DCAOFFSET_OFFSET);
 649         if (dca_offset == 0)
 650                 return NULL;
 651
 652         slots = ioat3_dca_count_dca_slots(iobase, dca_offset);
 653         if (slots == 0)
 654                 return NULL;
 655
 656         dca = alloc_dca_provider(&ioat3_dca_ops,
 657                                  sizeof(*ioatdca)
 658                                       + (sizeof(struct ioat_dca_slot) * slots));
 659         if (!dca)
 660                 return NULL;
 661
 662         ioatdca = dca_priv(dca);
 663         ioatdca->iobase = iobase;
 664         ioatdca->dca_base = iobase + dca_offset;
 665         ioatdca->max_requesters = slots;
 666
 667         /* some bios might not know to turn these on */
 668         csi_fsb_control = readw(ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
 669         if ((csi_fsb_control & IOAT3_CSI_CONTROL_PREFETCH) == 0) {
 670                 csi_fsb_control |= IOAT3_CSI_CONTROL_PREFETCH;
 671                 writew(csi_fsb_control,
 672                        ioatdca->dca_base + IOAT3_CSI_CONTROL_OFFSET);
 673         }
 674         pcie_control = readw(ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
 675         if ((pcie_control & IOAT3_PCI_CONTROL_MEMWR) == 0) {
 676                 pcie_control |= IOAT3_PCI_CONTROL_MEMWR;
 677                 writew(pcie_control,
 678                        ioatdca->dca_base + IOAT3_PCI_CONTROL_OFFSET);
 679         }
 680
 681
 682         /* TODO version, compatibility and configuration checks */
 683
 684         /* copy out the APIC to DCA tag map */
 685         tag_map.low =
 686                 readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_LOW);
 687         tag_map.high =
 688                 readl(ioatdca->dca_base + IOAT3_APICID_TAG_MAP_OFFSET_HIGH);
 689         for (i = 0; i < 8; i++) {
 690                 bit = tag_map.full >> (8 * i);
 691                 ioatdca->tag_map[i] = bit & DCA_TAG_MAP_MASK;
 692         }
 693
 694         if (dca3_tag_map_invalid(ioatdca->tag_map)) {
 695                 WARN_TAINT_ONCE(1, TAINT_FIRMWARE_WORKAROUND,
 696                                 "%s %s: APICID_TAG_MAP set incorrectly by BIOS, disabling DCA\n",
 697                                 dev_driver_string(&pdev->dev),
 698                                 dev_name(&pdev->dev));
 699                 free_dca_provider(dca);
 700                 return NULL;
 701         }
 702
 703         err = register_dca_provider(dca, &pdev->dev);
 704         if (err) {
 705                 free_dca_provider(dca);
 706                 return NULL;
 707         }
 708
 709         return dca;
 710 }