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); 536 537