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