arch/powerpc/platforms/pseries/msi.c

   1 /*
   2  * Copyright 2006 Jake Moilanen <moilanen@austin.ibm.com>, IBM Corp.
   3  * Copyright 2006-2007 Michael Ellerman, IBM Corp.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; version 2 of the
   8  * License.
   9  *
  10  */
  11
  12 #include <linux/device.h>
  13 #include <linux/irq.h>
  14 #include <linux/msi.h>
  15
  16 #include <asm/rtas.h>
  17 #include <asm/hw_irq.h>
  18 #include <asm/ppc-pci.h>
  19
  20 static int query_token, change_token;
  21
  22 #define RTAS_QUERY_FN           0
  23 #define RTAS_CHANGE_FN          1
  24 #define RTAS_RESET_FN           2
  25 #define RTAS_CHANGE_MSI_FN      3
  26 #define RTAS_CHANGE_MSIX_FN     4
  27 #define RTAS_CHANGE_32MSI_FN    5
  28
  29 /* RTAS Helpers */
  30
  31 static int rtas_change_msi(struct pci_dn *pdn, u32 func, u32 num_irqs)
  32 {
  33         u32 addr, seq_num, rtas_ret[3];
  34         unsigned long buid;
  35         int rc;
  36
  37         addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
  38         buid = pdn->phb->buid;
  39
  40         seq_num = 1;
  41         do {
  42                 if (func == RTAS_CHANGE_MSI_FN || func == RTAS_CHANGE_MSIX_FN ||
  43                     func == RTAS_CHANGE_32MSI_FN)
  44                         rc = rtas_call(change_token, 6, 4, rtas_ret, addr,
  45                                         BUID_HI(buid), BUID_LO(buid),
  46                                         func, num_irqs, seq_num);
  47                 else
  48                         rc = rtas_call(change_token, 6, 3, rtas_ret, addr,
  49                                         BUID_HI(buid), BUID_LO(buid),
  50                                         func, num_irqs, seq_num);
  51
  52                 seq_num = rtas_ret[1];
  53         } while (rtas_busy_delay(rc));
  54
  55         /*
  56          * If the RTAS call succeeded, return the number of irqs allocated.
  57          * If not, make sure we return a negative error code.
  58          */
  59         if (rc == 0)
  60                 rc = rtas_ret[0];
  61         else if (rc > 0)
  62                 rc = -rc;
  63
  64         pr_debug("rtas_msi: ibm,change_msi(func=%d,num=%d), got %d rc = %d\n",
  65                  func, num_irqs, rtas_ret[0], rc);
  66
  67         return rc;
  68 }
  69
  70 static void rtas_disable_msi(struct pci_dev *pdev)
  71 {
  72         struct pci_dn *pdn;
  73
  74         pdn = pci_get_pdn(pdev);
  75         if (!pdn)
  76                 return;
  77
  78         /*
  79          * disabling MSI with the explicit interface also disables MSI-X
  80          */
  81         if (rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, 0) != 0) {
  82                 /*
  83                  * may have failed because explicit interface is not
  84                  * present
  85                  */
  86                 if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) {
  87                         pr_debug("rtas_msi: Setting MSIs to 0 failed!\n");
  88                 }
  89         }
  90 }
  91
  92 static int rtas_query_irq_number(struct pci_dn *pdn, int offset)
  93 {
  94         u32 addr, rtas_ret[2];
  95         unsigned long buid;
  96         int rc;
  97
  98         addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
  99         buid = pdn->phb->buid;
 100
 101         do {
 102                 rc = rtas_call(query_token, 4, 3, rtas_ret, addr,
 103                                BUID_HI(buid), BUID_LO(buid), offset);
 104         } while (rtas_busy_delay(rc));
 105
 106         if (rc) {
 107                 pr_debug("rtas_msi: error (%d) querying source number\n", rc);
 108                 return rc;
 109         }
 110
 111         return rtas_ret[0];
 112 }
 113
 114 static void rtas_teardown_msi_irqs(struct pci_dev *pdev)
 115 {
 116         struct msi_desc *entry;
 117
 118         list_for_each_entry(entry, &pdev->msi_list, list) {
 119                 if (entry->irq == NO_IRQ)
 120                         continue;
 121
 122                 irq_set_msi_desc(entry->irq, NULL);
 123                 irq_dispose_mapping(entry->irq);
 124         }
 125
 126         rtas_disable_msi(pdev);
 127 }
 128
 129 static int check_req(struct pci_dev *pdev, int nvec, char *prop_name)
 130 {
 131         struct device_node *dn;
 132         struct pci_dn *pdn;
 133         const __be32 *p;
 134         u32 req_msi;
 135
 136         pdn = pci_get_pdn(pdev);
 137         if (!pdn)
 138                 return -ENODEV;
 139
 140         dn = pdn->node;
 141
 142         p = of_get_property(dn, prop_name, NULL);
 143         if (!p) {
 144                 pr_debug("rtas_msi: No %s on %s\n", prop_name, dn->full_name);
 145                 return -ENOENT;
 146         }
 147
 148         req_msi = be32_to_cpup(p);
 149         if (req_msi < nvec) {
 150                 pr_debug("rtas_msi: %s requests < %d MSIs\n", prop_name, nvec);
 151
 152                 if (req_msi == 0) /* Be paranoid */
 153                         return -ENOSPC;
 154
 155                 return req_msi;
 156         }
 157
 158         return 0;
 159 }
 160
 161 static int check_req_msi(struct pci_dev *pdev, int nvec)
 162 {
 163         return check_req(pdev, nvec, "ibm,req#msi");
 164 }
 165
 166 static int check_req_msix(struct pci_dev *pdev, int nvec)
 167 {
 168         return check_req(pdev, nvec, "ibm,req#msi-x");
 169 }
 170
 171 /* Quota calculation */
 172
 173 static struct device_node *find_pe_total_msi(struct pci_dev *dev, int *total)
 174 {
 175         struct device_node *dn;
 176         const __be32 *p;
 177
 178         dn = of_node_get(pci_device_to_OF_node(dev));
 179         while (dn) {
 180                 p = of_get_property(dn, "ibm,pe-total-#msi", NULL);
 181                 if (p) {
 182                         pr_debug("rtas_msi: found prop on dn %s\n",
 183                                 dn->full_name);
 184                         *total = be32_to_cpup(p);
 185                         return dn;
 186                 }
 187
 188                 dn = of_get_next_parent(dn);
 189         }
 190
 191         return NULL;
 192 }
 193
 194 static struct device_node *find_pe_dn(struct pci_dev *dev, int *total)
 195 {
 196         struct device_node *dn;
 197         struct eeh_dev *edev;
 198
 199         /* Found our PE and assume 8 at that point. */
 200
 201         dn = pci_device_to_OF_node(dev);
 202         if (!dn)
 203                 return NULL;
 204
 205         /* Get the top level device in the PE */
 206         edev = of_node_to_eeh_dev(dn);
 207         if (edev->pe)
 208                 edev = list_first_entry(&edev->pe->edevs, struct eeh_dev, list);
 209         dn = eeh_dev_to_of_node(edev);
 210         if (!dn)
 211                 return NULL;
 212
 213         /* We actually want the parent */
 214         dn = of_get_parent(dn);
 215         if (!dn)
 216                 return NULL;
 217
 218         /* Hardcode of 8 for old firmwares */
 219         *total = 8;
 220         pr_debug("rtas_msi: using PE dn %s\n", dn->full_name);
 221
 222         return dn;
 223 }
 224
 225 struct msi_counts {
 226         struct device_node *requestor;
 227         int num_devices;
 228         int request;
 229         int quota;
 230         int spare;
 231         int over_quota;
 232 };
 233
 234 static void *count_non_bridge_devices(struct device_node *dn, void *data)
 235 {
 236         struct msi_counts *counts = data;
 237         const __be32 *p;
 238         u32 class;
 239
 240         pr_debug("rtas_msi: counting %s\n", dn->full_name);
 241
 242         p = of_get_property(dn, "class-code", NULL);
 243         class = p ? be32_to_cpup(p) : 0;
 244
 245         if ((class >> 8) != PCI_CLASS_BRIDGE_PCI)
 246                 counts->num_devices++;
 247
 248         return NULL;
 249 }
 250
 251 static void *count_spare_msis(struct device_node *dn, void *data)
 252 {
 253         struct msi_counts *counts = data;
 254         const __be32 *p;
 255         int req;
 256
 257         if (dn == counts->requestor)
 258                 req = counts->request;
 259         else {
 260                 /* We don't know if a driver will try to use MSI or MSI-X,
 261                  * so we just have to punt and use the larger of the two. */
 262                 req = 0;
 263                 p = of_get_property(dn, "ibm,req#msi", NULL);
 264                 if (p)
 265                         req = be32_to_cpup(p);
 266
 267                 p = of_get_property(dn, "ibm,req#msi-x", NULL);
 268                 if (p)
 269                         req = max(req, (int)be32_to_cpup(p));
 270         }
 271
 272         if (req < counts->quota)
 273                 counts->spare += counts->quota - req;
 274         else if (req > counts->quota)
 275                 counts->over_quota++;
 276
 277         return NULL;
 278 }
 279
 280 static int msi_quota_for_device(struct pci_dev *dev, int request)
 281 {
 282         struct device_node *pe_dn;
 283         struct msi_counts counts;
 284         int total;
 285
 286         pr_debug("rtas_msi: calc quota for %s, request %d\n", pci_name(dev),
 287                   request);
 288
 289         pe_dn = find_pe_total_msi(dev, &total);
 290         if (!pe_dn)
 291                 pe_dn = find_pe_dn(dev, &total);
 292
 293         if (!pe_dn) {
 294                 pr_err("rtas_msi: couldn't find PE for %s\n", pci_name(dev));
 295                 goto out;
 296         }
 297
 298         pr_debug("rtas_msi: found PE %s\n", pe_dn->full_name);
 299
 300         memset(&counts, 0, sizeof(struct msi_counts));
 301
 302         /* Work out how many devices we have below this PE */
 303         traverse_pci_devices(pe_dn, count_non_bridge_devices, &counts);
 304
 305         if (counts.num_devices == 0) {
 306                 pr_err("rtas_msi: found 0 devices under PE for %s\n",
 307                         pci_name(dev));
 308                 goto out;
 309         }
 310
 311         counts.quota = total / counts.num_devices;
 312         if (request <= counts.quota)
 313                 goto out;
 314
 315         /* else, we have some more calculating to do */
 316         counts.requestor = pci_device_to_OF_node(dev);
 317         counts.request = request;
 318         traverse_pci_devices(pe_dn, count_spare_msis, &counts);
 319
 320         /* If the quota isn't an integer multiple of the total, we can
 321          * use the remainder as spare MSIs for anyone that wants them. */
 322         counts.spare += total % counts.num_devices;
 323
 324         /* Divide any spare by the number of over-quota requestors */
 325         if (counts.over_quota)
 326                 counts.quota += counts.spare / counts.over_quota;
 327
 328         /* And finally clamp the request to the possibly adjusted quota */
 329         request = min(counts.quota, request);
 330
 331         pr_debug("rtas_msi: request clamped to quota %d\n", request);
 332 out:
 333         of_node_put(pe_dn);
 334
 335         return request;
 336 }
 337
 338 static int rtas_msi_check_device(struct pci_dev *pdev, int nvec, int type)
 339 {
 340         int quota, rc;
 341
 342         if (type == PCI_CAP_ID_MSIX)
 343                 rc = check_req_msix(pdev, nvec);
 344         else
 345                 rc = check_req_msi(pdev, nvec);
 346
 347         if (rc)
 348                 return rc;
 349
 350         quota = msi_quota_for_device(pdev, nvec);
 351
 352         if (quota && quota < nvec)
 353                 return quota;
 354
 355         return 0;
 356 }
 357
 358 static int check_msix_entries(struct pci_dev *pdev)
 359 {
 360         struct msi_desc *entry;
 361         int expected;
 362
 363         /* There's no way for us to express to firmware that we want
 364          * a discontiguous, or non-zero based, range of MSI-X entries.
 365          * So we must reject such requests. */
 366
 367         expected = 0;
 368         list_for_each_entry(entry, &pdev->msi_list, list) {
 369                 if (entry->msi_attrib.entry_nr != expected) {
 370                         pr_debug("rtas_msi: bad MSI-X entries.\n");
 371                         return -EINVAL;
 372                 }
 373                 expected++;
 374         }
 375
 376         return 0;
 377 }
 378
 379 static void rtas_hack_32bit_msi_gen2(struct pci_dev *pdev)
 380 {
 381         u32 addr_hi, addr_lo;
 382
 383         /*
 384          * We should only get in here for IODA1 configs. This is based on the
 385          * fact that we using RTAS for MSIs, we don't have the 32 bit MSI RTAS
 386          * support, and we are in a PCIe Gen2 slot.
 387          */
 388         dev_info(&pdev->dev,
 389                  "rtas_msi: No 32 bit MSI firmware support, forcing 32 bit MSI\n");
 390         pci_read_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, &addr_hi);
 391         addr_lo = 0xffff0000 | ((addr_hi >> (48 - 32)) << 4);
 392         pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_LO, addr_lo);
 393         pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, 0);
 394 }
 395
 396 static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type)
 397 {
 398         struct pci_dn *pdn;
 399         int hwirq, virq, i, rc;
 400         struct msi_desc *entry;
 401         struct msi_msg msg;
 402         int nvec = nvec_in;
 403         int use_32bit_msi_hack = 0;
 404
 405         pdn = pci_get_pdn(pdev);
 406         if (!pdn)
 407                 return -ENODEV;
 408
 409         if (type == PCI_CAP_ID_MSIX && check_msix_entries(pdev))
 410                 return -EINVAL;
 411
 412         /*
 413          * Firmware currently refuse any non power of two allocation
 414          * so we round up if the quota will allow it.
 415          */
 416         if (type == PCI_CAP_ID_MSIX) {
 417                 int m = roundup_pow_of_two(nvec);
 418                 int quota = msi_quota_for_device(pdev, m);
 419
 420                 if (quota >= m)
 421                         nvec = m;
 422         }
 423
 424         /*
 425          * Try the new more explicit firmware interface, if that fails fall
 426          * back to the old interface. The old interface is known to never
 427          * return MSI-Xs.
 428          */
 429 again:
 430         if (type == PCI_CAP_ID_MSI) {
 431                 if (pdn->force_32bit_msi) {
 432                         rc = rtas_change_msi(pdn, RTAS_CHANGE_32MSI_FN, nvec);
 433                         if (rc < 0) {
 434                                 /*
 435                                  * We only want to run the 32 bit MSI hack below if
 436                                  * the max bus speed is Gen2 speed
 437                                  */
 438                                 if (pdev->bus->max_bus_speed != PCIE_SPEED_5_0GT)
 439                                         return rc;
 440
 441                                 use_32bit_msi_hack = 1;
 442                         }
 443                 } else
 444                         rc = -1;
 445
 446                 if (rc < 0)
 447                         rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec);
 448
 449                 if (rc < 0) {
 450                         pr_debug("rtas_msi: trying the old firmware call.\n");
 451                         rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec);
 452                 }
 453
 454                 if (use_32bit_msi_hack && rc > 0)
 455                         rtas_hack_32bit_msi_gen2(pdev);
 456         } else
 457                 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
 458
 459         if (rc != nvec) {
 460                 if (nvec != nvec_in) {
 461                         nvec = nvec_in;
 462                         goto again;
 463                 }
 464                 pr_debug("rtas_msi: rtas_change_msi() failed\n");
 465                 return rc;
 466         }
 467
 468         i = 0;
 469         list_for_each_entry(entry, &pdev->msi_list, list) {
 470                 hwirq = rtas_query_irq_number(pdn, i++);
 471                 if (hwirq < 0) {
 472                         pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
 473                         return hwirq;
 474                 }
 475
 476                 virq = irq_create_mapping(NULL, hwirq);
 477
 478                 if (virq == NO_IRQ) {
 479                         pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
 480                         return -ENOSPC;
 481                 }
 482
 483                 dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
 484                 irq_set_msi_desc(virq, entry);
 485
 486                 /* Read config space back so we can restore after reset */
 487                 read_msi_msg(virq, &msg);
 488                 entry->msg = msg;
 489         }
 490
 491         return 0;
 492 }
 493
 494 static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
 495 {
 496         /* No LSI -> leave MSIs (if any) configured */
 497         if (pdev->irq == NO_IRQ) {
 498                 dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n");
 499                 return;
 500         }
 501
 502         /* No MSI -> MSIs can't have been assigned by fw, leave LSI */
 503         if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) {
 504                 dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n");
 505                 return;
 506         }
 507
 508         dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n");
 509         rtas_disable_msi(pdev);
 510 }
 511
 512 static int rtas_msi_init(void)
 513 {
 514         query_token  = rtas_token("ibm,query-interrupt-source-number");
 515         change_token = rtas_token("ibm,change-msi");
 516
 517         if ((query_token == RTAS_UNKNOWN_SERVICE) ||
 518                         (change_token == RTAS_UNKNOWN_SERVICE)) {
 519                 pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n");
 520                 return -1;
 521         }
 522
 523         pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n");
 524
 525         WARN_ON(ppc_md.setup_msi_irqs);
 526         ppc_md.setup_msi_irqs = rtas_setup_msi_irqs;
 527         ppc_md.teardown_msi_irqs = rtas_teardown_msi_irqs;
 528         ppc_md.msi_check_device = rtas_msi_check_device;
 529
 530         WARN_ON(ppc_md.pci_irq_fixup);
 531         ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup;
 532
 533         return 0;
 534 }
 535 arch_initcall(rtas_msi_init);
 536