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