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 #include "pseries.h"
  22
  23 static int query_token, change_token;
  24
  25 #define RTAS_QUERY_FN           0
  26 #define RTAS_CHANGE_FN          1
  27 #define RTAS_RESET_FN           2
  28 #define RTAS_CHANGE_MSI_FN      3
  29 #define RTAS_CHANGE_MSIX_FN     4
  30 #define RTAS_CHANGE_32MSI_FN    5
  31
  32 /* RTAS Helpers */
  33
  34 static int rtas_change_msi(struct pci_dn *pdn, u32 func, u32 num_irqs)
  35 {
  36         u32 addr, seq_num, rtas_ret[3];
  37         unsigned long buid;
  38         int rc;
  39
  40         addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
  41         buid = pdn->phb->buid;
  42
  43         seq_num = 1;
  44         do {
  45                 if (func == RTAS_CHANGE_MSI_FN || func == RTAS_CHANGE_MSIX_FN ||
  46                     func == RTAS_CHANGE_32MSI_FN)
  47                         rc = rtas_call(change_token, 6, 4, rtas_ret, addr,
  48                                         BUID_HI(buid), BUID_LO(buid),
  49                                         func, num_irqs, seq_num);
  50                 else
  51                         rc = rtas_call(change_token, 6, 3, rtas_ret, addr,
  52                                         BUID_HI(buid), BUID_LO(buid),
  53                                         func, num_irqs, seq_num);
  54
  55                 seq_num = rtas_ret[1];
  56         } while (rtas_busy_delay(rc));
  57
  58         /*
  59          * If the RTAS call succeeded, return the number of irqs allocated.
  60          * If not, make sure we return a negative error code.
  61          */
  62         if (rc == 0)
  63                 rc = rtas_ret[0];
  64         else if (rc > 0)
  65                 rc = -rc;
  66
  67         pr_debug("rtas_msi: ibm,change_msi(func=%d,num=%d), got %d rc = %d\n",
  68                  func, num_irqs, rtas_ret[0], rc);
  69
  70         return rc;
  71 }
  72
  73 static void rtas_disable_msi(struct pci_dev *pdev)
  74 {
  75         struct pci_dn *pdn;
  76
  77         pdn = pci_get_pdn(pdev);
  78         if (!pdn)
  79                 return;
  80
  81         /*
  82          * disabling MSI with the explicit interface also disables MSI-X
  83          */
  84         if (rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, 0) != 0) {
  85                 /*
  86                  * may have failed because explicit interface is not
  87                  * present
  88                  */
  89                 if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) {
  90                         pr_debug("rtas_msi: Setting MSIs to 0 failed!\n");
  91                 }
  92         }
  93 }
  94
  95 static int rtas_query_irq_number(struct pci_dn *pdn, int offset)
  96 {
  97         u32 addr, rtas_ret[2];
  98         unsigned long buid;
  99         int rc;
 100
 101         addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
 102         buid = pdn->phb->buid;
 103
 104         do {
 105                 rc = rtas_call(query_token, 4, 3, rtas_ret, addr,
 106                                BUID_HI(buid), BUID_LO(buid), offset);
 107         } while (rtas_busy_delay(rc));
 108
 109         if (rc) {
 110                 pr_debug("rtas_msi: error (%d) querying source number\n", rc);
 111                 return rc;
 112         }
 113
 114         return rtas_ret[0];
 115 }
 116
 117 static void rtas_teardown_msi_irqs(struct pci_dev *pdev)
 118 {
 119         struct msi_desc *entry;
 120
 121         for_each_pci_msi_entry(entry, pdev) {
 122                 if (!entry->irq)
 123                         continue;
 124
 125                 irq_set_msi_desc(entry->irq, NULL);
 126                 irq_dispose_mapping(entry->irq);
 127         }
 128
 129         rtas_disable_msi(pdev);
 130 }
 131
 132 static int check_req(struct pci_dev *pdev, int nvec, char *prop_name)
 133 {
 134         struct device_node *dn;
 135         struct pci_dn *pdn;
 136         const __be32 *p;
 137         u32 req_msi;
 138
 139         pdn = pci_get_pdn(pdev);
 140         if (!pdn)
 141                 return -ENODEV;
 142
 143         dn = pdn->node;
 144
 145         p = of_get_property(dn, prop_name, NULL);
 146         if (!p) {
 147                 pr_debug("rtas_msi: No %s on %s\n", prop_name, dn->full_name);
 148                 return -ENOENT;
 149         }
 150
 151         req_msi = be32_to_cpup(p);
 152         if (req_msi < nvec) {
 153                 pr_debug("rtas_msi: %s requests < %d MSIs\n", prop_name, nvec);
 154
 155                 if (req_msi == 0) /* Be paranoid */
 156                         return -ENOSPC;
 157
 158                 return req_msi;
 159         }
 160
 161         return 0;
 162 }
 163
 164 static int check_req_msi(struct pci_dev *pdev, int nvec)
 165 {
 166         return check_req(pdev, nvec, "ibm,req#msi");
 167 }
 168
 169 static int check_req_msix(struct pci_dev *pdev, int nvec)
 170 {
 171         return check_req(pdev, nvec, "ibm,req#msi-x");
 172 }
 173
 174 /* Quota calculation */
 175
 176 static struct device_node *find_pe_total_msi(struct pci_dev *dev, int *total)
 177 {
 178         struct device_node *dn;
 179         const __be32 *p;
 180
 181         dn = of_node_get(pci_device_to_OF_node(dev));
 182         while (dn) {
 183                 p = of_get_property(dn, "ibm,pe-total-#msi", NULL);
 184                 if (p) {
 185                         pr_debug("rtas_msi: found prop on dn %s\n",
 186                                 dn->full_name);
 187                         *total = be32_to_cpup(p);
 188                         return dn;
 189                 }
 190
 191                 dn = of_get_next_parent(dn);
 192         }
 193
 194         return NULL;
 195 }
 196
 197 static struct device_node *find_pe_dn(struct pci_dev *dev, int *total)
 198 {
 199         struct device_node *dn;
 200         struct pci_dn *pdn;
 201         struct eeh_dev *edev;
 202
 203         /* Found our PE and assume 8 at that point. */
 204
 205         dn = pci_device_to_OF_node(dev);
 206         if (!dn)
 207                 return NULL;
 208
 209         /* Get the top level device in the PE */
 210         edev = pdn_to_eeh_dev(PCI_DN(dn));
 211         if (edev->pe)
 212                 edev = list_first_entry(&edev->pe->edevs, struct eeh_dev, list);
 213         pdn = eeh_dev_to_pdn(edev);
 214         dn = pdn ? pdn->node : NULL;
 215         if (!dn)
 216                 return NULL;
 217
 218         /* We actually want the parent */
 219         dn = of_get_parent(dn);
 220         if (!dn)
 221                 return NULL;
 222
 223         /* Hardcode of 8 for old firmwares */
 224         *total = 8;
 225         pr_debug("rtas_msi: using PE dn %s\n", dn->full_name);
 226
 227         return dn;
 228 }
 229
 230 struct msi_counts {
 231         struct device_node *requestor;
 232         int num_devices;
 233         int request;
 234         int quota;
 235         int spare;
 236         int over_quota;
 237 };
 238
 239 static void *count_non_bridge_devices(struct device_node *dn, void *data)
 240 {
 241         struct msi_counts *counts = data;
 242         const __be32 *p;
 243         u32 class;
 244
 245         pr_debug("rtas_msi: counting %s\n", dn->full_name);
 246
 247         p = of_get_property(dn, "class-code", NULL);
 248         class = p ? be32_to_cpup(p) : 0;
 249
 250         if ((class >> 8) != PCI_CLASS_BRIDGE_PCI)
 251                 counts->num_devices++;
 252
 253         return NULL;
 254 }
 255
 256 static void *count_spare_msis(struct device_node *dn, void *data)
 257 {
 258         struct msi_counts *counts = data;
 259         const __be32 *p;
 260         int req;
 261
 262         if (dn == counts->requestor)
 263                 req = counts->request;
 264         else {
 265                 /* We don't know if a driver will try to use MSI or MSI-X,
 266                  * so we just have to punt and use the larger of the two. */
 267                 req = 0;
 268                 p = of_get_property(dn, "ibm,req#msi", NULL);
 269                 if (p)
 270                         req = be32_to_cpup(p);
 271
 272                 p = of_get_property(dn, "ibm,req#msi-x", NULL);
 273                 if (p)
 274                         req = max(req, (int)be32_to_cpup(p));
 275         }
 276
 277         if (req < counts->quota)
 278                 counts->spare += counts->quota - req;
 279         else if (req > counts->quota)
 280                 counts->over_quota++;
 281
 282         return NULL;
 283 }
 284
 285 static int msi_quota_for_device(struct pci_dev *dev, int request)
 286 {
 287         struct device_node *pe_dn;
 288         struct msi_counts counts;
 289         int total;
 290
 291         pr_debug("rtas_msi: calc quota for %s, request %d\n", pci_name(dev),
 292                   request);
 293
 294         pe_dn = find_pe_total_msi(dev, &total);
 295         if (!pe_dn)
 296                 pe_dn = find_pe_dn(dev, &total);
 297
 298         if (!pe_dn) {
 299                 pr_err("rtas_msi: couldn't find PE for %s\n", pci_name(dev));
 300                 goto out;
 301         }
 302
 303         pr_debug("rtas_msi: found PE %s\n", pe_dn->full_name);
 304
 305         memset(&counts, 0, sizeof(struct msi_counts));
 306
 307         /* Work out how many devices we have below this PE */
 308         pci_traverse_device_nodes(pe_dn, count_non_bridge_devices, &counts);
 309
 310         if (counts.num_devices == 0) {
 311                 pr_err("rtas_msi: found 0 devices under PE for %s\n",
 312                         pci_name(dev));
 313                 goto out;
 314         }
 315
 316         counts.quota = total / counts.num_devices;
 317         if (request <= counts.quota)
 318                 goto out;
 319
 320         /* else, we have some more calculating to do */
 321         counts.requestor = pci_device_to_OF_node(dev);
 322         counts.request = request;
 323         pci_traverse_device_nodes(pe_dn, count_spare_msis, &counts);
 324
 325         /* If the quota isn't an integer multiple of the total, we can
 326          * use the remainder as spare MSIs for anyone that wants them. */
 327         counts.spare += total % counts.num_devices;
 328
 329         /* Divide any spare by the number of over-quota requestors */
 330         if (counts.over_quota)
 331                 counts.quota += counts.spare / counts.over_quota;
 332
 333         /* And finally clamp the request to the possibly adjusted quota */
 334         request = min(counts.quota, request);
 335
 336         pr_debug("rtas_msi: request clamped to quota %d\n", request);
 337 out:
 338         of_node_put(pe_dn);
 339
 340         return request;
 341 }
 342
 343 static int check_msix_entries(struct pci_dev *pdev)
 344 {
 345         struct msi_desc *entry;
 346         int expected;
 347
 348         /* There's no way for us to express to firmware that we want
 349          * a discontiguous, or non-zero based, range of MSI-X entries.
 350          * So we must reject such requests. */
 351
 352         expected = 0;
 353         for_each_pci_msi_entry(entry, pdev) {
 354                 if (entry->msi_attrib.entry_nr != expected) {
 355                         pr_debug("rtas_msi: bad MSI-X entries.\n");
 356                         return -EINVAL;
 357                 }
 358                 expected++;
 359         }
 360
 361         return 0;
 362 }
 363
 364 static void rtas_hack_32bit_msi_gen2(struct pci_dev *pdev)
 365 {
 366         u32 addr_hi, addr_lo;
 367
 368         /*
 369          * We should only get in here for IODA1 configs. This is based on the
 370          * fact that we using RTAS for MSIs, we don't have the 32 bit MSI RTAS
 371          * support, and we are in a PCIe Gen2 slot.
 372          */
 373         dev_info(&pdev->dev,
 374                  "rtas_msi: No 32 bit MSI firmware support, forcing 32 bit MSI\n");
 375         pci_read_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, &addr_hi);
 376         addr_lo = 0xffff0000 | ((addr_hi >> (48 - 32)) << 4);
 377         pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_LO, addr_lo);
 378         pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, 0);
 379 }
 380
 381 static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type)
 382 {
 383         struct pci_dn *pdn;
 384         int hwirq, virq, i, quota, rc;
 385         struct msi_desc *entry;
 386         struct msi_msg msg;
 387         int nvec = nvec_in;
 388         int use_32bit_msi_hack = 0;
 389
 390         if (type == PCI_CAP_ID_MSIX)
 391                 rc = check_req_msix(pdev, nvec);
 392         else
 393                 rc = check_req_msi(pdev, nvec);
 394
 395         if (rc)
 396                 return rc;
 397
 398         quota = msi_quota_for_device(pdev, nvec);
 399
 400         if (quota && quota < nvec)
 401                 return quota;
 402
 403         if (type == PCI_CAP_ID_MSIX && check_msix_entries(pdev))
 404                 return -EINVAL;
 405
 406         /*
 407          * Firmware currently refuse any non power of two allocation
 408          * so we round up if the quota will allow it.
 409          */
 410         if (type == PCI_CAP_ID_MSIX) {
 411                 int m = roundup_pow_of_two(nvec);
 412                 quota = msi_quota_for_device(pdev, m);
 413
 414                 if (quota >= m)
 415                         nvec = m;
 416         }
 417
 418         pdn = pci_get_pdn(pdev);
 419
 420         /*
 421          * Try the new more explicit firmware interface, if that fails fall
 422          * back to the old interface. The old interface is known to never
 423          * return MSI-Xs.
 424          */
 425 again:
 426         if (type == PCI_CAP_ID_MSI) {
 427                 if (pdev->no_64bit_msi) {
 428                         rc = rtas_change_msi(pdn, RTAS_CHANGE_32MSI_FN, nvec);
 429                         if (rc < 0) {
 430                                 /*
 431                                  * We only want to run the 32 bit MSI hack below if
 432                                  * the max bus speed is Gen2 speed
 433                                  */
 434                                 if (pdev->bus->max_bus_speed != PCIE_SPEED_5_0GT)
 435                                         return rc;
 436
 437                                 use_32bit_msi_hack = 1;
 438                         }
 439                 } else
 440                         rc = -1;
 441
 442                 if (rc < 0)
 443                         rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec);
 444
 445                 if (rc < 0) {
 446                         pr_debug("rtas_msi: trying the old firmware call.\n");
 447                         rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec);
 448                 }
 449
 450                 if (use_32bit_msi_hack && rc > 0)
 451                         rtas_hack_32bit_msi_gen2(pdev);
 452         } else
 453                 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
 454
 455         if (rc != nvec) {
 456                 if (nvec != nvec_in) {
 457                         nvec = nvec_in;
 458                         goto again;
 459                 }
 460                 pr_debug("rtas_msi: rtas_change_msi() failed\n");
 461                 return rc;
 462         }
 463
 464         i = 0;
 465         for_each_pci_msi_entry(entry, pdev) {
 466                 hwirq = rtas_query_irq_number(pdn, i++);
 467                 if (hwirq < 0) {
 468                         pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
 469                         return hwirq;
 470                 }
 471
 472                 virq = irq_create_mapping(NULL, hwirq);
 473
 474                 if (!virq) {
 475                         pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
 476                         return -ENOSPC;
 477                 }
 478
 479                 dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
 480                 irq_set_msi_desc(virq, entry);
 481
 482                 /* Read config space back so we can restore after reset */
 483                 __pci_read_msi_msg(entry, &msg);
 484                 entry->msg = msg;
 485         }
 486
 487         return 0;
 488 }
 489
 490 static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
 491 {
 492         /* No LSI -> leave MSIs (if any) configured */
 493         if (!pdev->irq) {
 494                 dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n");
 495                 return;
 496         }
 497
 498         /* No MSI -> MSIs can't have been assigned by fw, leave LSI */
 499         if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) {
 500                 dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n");
 501                 return;
 502         }
 503
 504         dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n");
 505         rtas_disable_msi(pdev);
 506 }
 507
 508 static int rtas_msi_init(void)
 509 {
 510         struct pci_controller *phb;
 511
 512         query_token  = rtas_token("ibm,query-interrupt-source-number");
 513         change_token = rtas_token("ibm,change-msi");
 514
 515         if ((query_token == RTAS_UNKNOWN_SERVICE) ||
 516                         (change_token == RTAS_UNKNOWN_SERVICE)) {
 517                 pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n");
 518                 return -1;
 519         }
 520
 521         pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n");
 522
 523         WARN_ON(pseries_pci_controller_ops.setup_msi_irqs);
 524         pseries_pci_controller_ops.setup_msi_irqs = rtas_setup_msi_irqs;
 525         pseries_pci_controller_ops.teardown_msi_irqs = rtas_teardown_msi_irqs;
 526
 527         list_for_each_entry(phb, &hose_list, list_node) {
 528                 WARN_ON(phb->controller_ops.setup_msi_irqs);
 529                 phb->controller_ops.setup_msi_irqs = rtas_setup_msi_irqs;
 530                 phb->controller_ops.teardown_msi_irqs = rtas_teardown_msi_irqs;
 531         }
 532
 533         WARN_ON(ppc_md.pci_irq_fixup);
 534         ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup;
 535
 536         return 0;
 537 }
 538 machine_arch_initcall(pseries, rtas_msi_init);