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 rtas_msi_check_device(struct pci_dev *pdev, int nvec, int type) 340 { 341 int quota, rc; 342 343 if (type == PCI_CAP_ID_MSIX) 344 rc = check_req_msix(pdev, nvec); 345 else 346 rc = check_req_msi(pdev, nvec); 347 348 if (rc) 349 return rc; 350 351 quota = msi_quota_for_device(pdev, nvec); 352 353 if (quota && quota < nvec) 354 return quota; 355 356 return 0; 357 } 358 359 static int check_msix_entries(struct pci_dev *pdev) 360 { 361 struct msi_desc *entry; 362 int expected; 363 364 /* There's no way for us to express to firmware that we want 365 * a discontiguous, or non-zero based, range of MSI-X entries. 366 * So we must reject such requests. */ 367 368 expected = 0; 369 list_for_each_entry(entry, &pdev->msi_list, list) { 370 if (entry->msi_attrib.entry_nr != expected) { 371 pr_debug("rtas_msi: bad MSI-X entries.\n"); 372 return -EINVAL; 373 } 374 expected++; 375 } 376 377 return 0; 378 } 379 380 static void rtas_hack_32bit_msi_gen2(struct pci_dev *pdev) 381 { 382 u32 addr_hi, addr_lo; 383 384 /* 385 * We should only get in here for IODA1 configs. This is based on the 386 * fact that we using RTAS for MSIs, we don't have the 32 bit MSI RTAS 387 * support, and we are in a PCIe Gen2 slot. 388 */ 389 dev_info(&pdev->dev, 390 "rtas_msi: No 32 bit MSI firmware support, forcing 32 bit MSI\n"); 391 pci_read_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, &addr_hi); 392 addr_lo = 0xffff0000 | ((addr_hi >> (48 - 32)) << 4); 393 pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_LO, addr_lo); 394 pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, 0); 395 } 396 397 static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type) 398 { 399 struct pci_dn *pdn; 400 int hwirq, virq, i, rc; 401 struct msi_desc *entry; 402 struct msi_msg msg; 403 int nvec = nvec_in; 404 int use_32bit_msi_hack = 0; 405 406 pdn = pci_get_pdn(pdev); 407 if (!pdn) 408 return -ENODEV; 409 410 if (type == PCI_CAP_ID_MSIX && check_msix_entries(pdev)) 411 return -EINVAL; 412 413 /* 414 * Firmware currently refuse any non power of two allocation 415 * so we round up if the quota will allow it. 416 */ 417 if (type == PCI_CAP_ID_MSIX) { 418 int m = roundup_pow_of_two(nvec); 419 int quota = msi_quota_for_device(pdev, m); 420 421 if (quota >= m) 422 nvec = m; 423 } 424 425 /* 426 * Try the new more explicit firmware interface, if that fails fall 427 * back to the old interface. The old interface is known to never 428 * return MSI-Xs. 429 */ 430 again: 431 if (type == PCI_CAP_ID_MSI) { 432 if (pdn->force_32bit_msi) { 433 rc = rtas_change_msi(pdn, RTAS_CHANGE_32MSI_FN, nvec); 434 if (rc < 0) { 435 /* 436 * We only want to run the 32 bit MSI hack below if 437 * the max bus speed is Gen2 speed 438 */ 439 if (pdev->bus->max_bus_speed != PCIE_SPEED_5_0GT) 440 return rc; 441 442 use_32bit_msi_hack = 1; 443 } 444 } else 445 rc = -1; 446 447 if (rc < 0) 448 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec); 449 450 if (rc < 0) { 451 pr_debug("rtas_msi: trying the old firmware call.\n"); 452 rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec); 453 } 454 455 if (use_32bit_msi_hack && rc > 0) 456 rtas_hack_32bit_msi_gen2(pdev); 457 } else 458 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec); 459 460 if (rc != nvec) { 461 if (nvec != nvec_in) { 462 nvec = nvec_in; 463 goto again; 464 } 465 pr_debug("rtas_msi: rtas_change_msi() failed\n"); 466 return rc; 467 } 468 469 i = 0; 470 list_for_each_entry(entry, &pdev->msi_list, list) { 471 hwirq = rtas_query_irq_number(pdn, i++); 472 if (hwirq < 0) { 473 pr_debug("rtas_msi: error (%d) getting hwirq\n", rc); 474 return hwirq; 475 } 476 477 virq = irq_create_mapping(NULL, hwirq); 478 479 if (virq == NO_IRQ) { 480 pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq); 481 return -ENOSPC; 482 } 483 484 dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq); 485 irq_set_msi_desc(virq, entry); 486 487 /* Read config space back so we can restore after reset */ 488 read_msi_msg(virq, &msg); 489 entry->msg = msg; 490 } 491 492 return 0; 493 } 494 495 static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev) 496 { 497 /* No LSI -> leave MSIs (if any) configured */ 498 if (pdev->irq == NO_IRQ) { 499 dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n"); 500 return; 501 } 502 503 /* No MSI -> MSIs can't have been assigned by fw, leave LSI */ 504 if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) { 505 dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n"); 506 return; 507 } 508 509 dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n"); 510 rtas_disable_msi(pdev); 511 } 512 513 static int rtas_msi_init(void) 514 { 515 query_token = rtas_token("ibm,query-interrupt-source-number"); 516 change_token = rtas_token("ibm,change-msi"); 517 518 if ((query_token == RTAS_UNKNOWN_SERVICE) || 519 (change_token == RTAS_UNKNOWN_SERVICE)) { 520 pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n"); 521 return -1; 522 } 523 524 pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n"); 525 526 WARN_ON(ppc_md.setup_msi_irqs); 527 ppc_md.setup_msi_irqs = rtas_setup_msi_irqs; 528 ppc_md.teardown_msi_irqs = rtas_teardown_msi_irqs; 529 ppc_md.msi_check_device = rtas_msi_check_device; 530 531 WARN_ON(ppc_md.pci_irq_fixup); 532 ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup; 533 534 return 0; 535 } 536 machine_arch_initcall(pseries, rtas_msi_init); 537