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 set_irq_msi(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; 213 214 /* Found our PE and assume 8 at that point. */ 215 216 dn = pci_device_to_OF_node(dev); 217 if (!dn) 218 return NULL; 219 220 dn = find_device_pe(dn); 221 if (!dn) 222 return NULL; 223 224 /* We actually want the parent */ 225 dn = of_get_parent(dn); 226 if (!dn) 227 return NULL; 228 229 /* Hardcode of 8 for old firmwares */ 230 *total = 8; 231 pr_debug("rtas_msi: using PE dn %s\n", dn->full_name); 232 233 return dn; 234 } 235 236 struct msi_counts { 237 struct device_node *requestor; 238 int num_devices; 239 int request; 240 int quota; 241 int spare; 242 int over_quota; 243 }; 244 245 static void *count_non_bridge_devices(struct device_node *dn, void *data) 246 { 247 struct msi_counts *counts = data; 248 const u32 *p; 249 u32 class; 250 251 pr_debug("rtas_msi: counting %s\n", dn->full_name); 252 253 p = of_get_property(dn, "class-code", NULL); 254 class = p ? *p : 0; 255 256 if ((class >> 8) != PCI_CLASS_BRIDGE_PCI) 257 counts->num_devices++; 258 259 return NULL; 260 } 261 262 static void *count_spare_msis(struct device_node *dn, void *data) 263 { 264 struct msi_counts *counts = data; 265 const u32 *p; 266 int req; 267 268 if (dn == counts->requestor) 269 req = counts->request; 270 else { 271 /* We don't know if a driver will try to use MSI or MSI-X, 272 * so we just have to punt and use the larger of the two. */ 273 req = 0; 274 p = of_get_property(dn, "ibm,req#msi", NULL); 275 if (p) 276 req = *p; 277 278 p = of_get_property(dn, "ibm,req#msi-x", NULL); 279 if (p) 280 req = max(req, (int)*p); 281 } 282 283 if (req < counts->quota) 284 counts->spare += counts->quota - req; 285 else if (req > counts->quota) 286 counts->over_quota++; 287 288 return NULL; 289 } 290 291 static int msi_quota_for_device(struct pci_dev *dev, int request) 292 { 293 struct device_node *pe_dn; 294 struct msi_counts counts; 295 int total; 296 297 pr_debug("rtas_msi: calc quota for %s, request %d\n", pci_name(dev), 298 request); 299 300 pe_dn = find_pe_total_msi(dev, &total); 301 if (!pe_dn) 302 pe_dn = find_pe_dn(dev, &total); 303 304 if (!pe_dn) { 305 pr_err("rtas_msi: couldn't find PE for %s\n", pci_name(dev)); 306 goto out; 307 } 308 309 pr_debug("rtas_msi: found PE %s\n", pe_dn->full_name); 310 311 memset(&counts, 0, sizeof(struct msi_counts)); 312 313 /* Work out how many devices we have below this PE */ 314 traverse_pci_devices(pe_dn, count_non_bridge_devices, &counts); 315 316 if (counts.num_devices == 0) { 317 pr_err("rtas_msi: found 0 devices under PE for %s\n", 318 pci_name(dev)); 319 goto out; 320 } 321 322 counts.quota = total / counts.num_devices; 323 if (request <= counts.quota) 324 goto out; 325 326 /* else, we have some more calculating to do */ 327 counts.requestor = pci_device_to_OF_node(dev); 328 counts.request = request; 329 traverse_pci_devices(pe_dn, count_spare_msis, &counts); 330 331 /* If the quota isn't an integer multiple of the total, we can 332 * use the remainder as spare MSIs for anyone that wants them. */ 333 counts.spare += total % counts.num_devices; 334 335 /* Divide any spare by the number of over-quota requestors */ 336 if (counts.over_quota) 337 counts.quota += counts.spare / counts.over_quota; 338 339 /* And finally clamp the request to the possibly adjusted quota */ 340 request = min(counts.quota, request); 341 342 pr_debug("rtas_msi: request clamped to quota %d\n", request); 343 out: 344 of_node_put(pe_dn); 345 346 return request; 347 } 348 349 static int rtas_msi_check_device(struct pci_dev *pdev, int nvec, int type) 350 { 351 int quota, rc; 352 353 if (type == PCI_CAP_ID_MSIX) 354 rc = check_req_msix(pdev, nvec); 355 else 356 rc = check_req_msi(pdev, nvec); 357 358 if (rc) 359 return rc; 360 361 quota = msi_quota_for_device(pdev, nvec); 362 363 if (quota && quota < nvec) 364 return quota; 365 366 return 0; 367 } 368 369 static int check_msix_entries(struct pci_dev *pdev) 370 { 371 struct msi_desc *entry; 372 int expected; 373 374 /* There's no way for us to express to firmware that we want 375 * a discontiguous, or non-zero based, range of MSI-X entries. 376 * So we must reject such requests. */ 377 378 expected = 0; 379 list_for_each_entry(entry, &pdev->msi_list, list) { 380 if (entry->msi_attrib.entry_nr != expected) { 381 pr_debug("rtas_msi: bad MSI-X entries.\n"); 382 return -EINVAL; 383 } 384 expected++; 385 } 386 387 return 0; 388 } 389 390 static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type) 391 { 392 struct pci_dn *pdn; 393 int hwirq, virq, i, rc; 394 struct msi_desc *entry; 395 struct msi_msg msg; 396 397 pdn = get_pdn(pdev); 398 if (!pdn) 399 return -ENODEV; 400 401 if (type == PCI_CAP_ID_MSIX && check_msix_entries(pdev)) 402 return -EINVAL; 403 404 /* 405 * Try the new more explicit firmware interface, if that fails fall 406 * back to the old interface. The old interface is known to never 407 * return MSI-Xs. 408 */ 409 if (type == PCI_CAP_ID_MSI) { 410 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec); 411 412 if (rc < 0) { 413 pr_debug("rtas_msi: trying the old firmware call.\n"); 414 rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec); 415 } 416 } else 417 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec); 418 419 if (rc != nvec) { 420 pr_debug("rtas_msi: rtas_change_msi() failed\n"); 421 return rc; 422 } 423 424 i = 0; 425 list_for_each_entry(entry, &pdev->msi_list, list) { 426 hwirq = rtas_query_irq_number(pdn, i++); 427 if (hwirq < 0) { 428 pr_debug("rtas_msi: error (%d) getting hwirq\n", rc); 429 return hwirq; 430 } 431 432 virq = irq_create_mapping(NULL, hwirq); 433 434 if (virq == NO_IRQ) { 435 pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq); 436 return -ENOSPC; 437 } 438 439 dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq); 440 set_irq_msi(virq, entry); 441 442 /* Read config space back so we can restore after reset */ 443 read_msi_msg(virq, &msg); 444 entry->msg = msg; 445 } 446 447 return 0; 448 } 449 450 static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev) 451 { 452 /* No LSI -> leave MSIs (if any) configured */ 453 if (pdev->irq == NO_IRQ) { 454 dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n"); 455 return; 456 } 457 458 /* No MSI -> MSIs can't have been assigned by fw, leave LSI */ 459 if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) { 460 dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n"); 461 return; 462 } 463 464 dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n"); 465 rtas_disable_msi(pdev); 466 } 467 468 static int rtas_msi_init(void) 469 { 470 query_token = rtas_token("ibm,query-interrupt-source-number"); 471 change_token = rtas_token("ibm,change-msi"); 472 473 if ((query_token == RTAS_UNKNOWN_SERVICE) || 474 (change_token == RTAS_UNKNOWN_SERVICE)) { 475 pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n"); 476 return -1; 477 } 478 479 pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n"); 480 481 WARN_ON(ppc_md.setup_msi_irqs); 482 ppc_md.setup_msi_irqs = rtas_setup_msi_irqs; 483 ppc_md.teardown_msi_irqs = rtas_teardown_msi_irqs; 484 ppc_md.msi_check_device = rtas_msi_check_device; 485 486 WARN_ON(ppc_md.pci_irq_fixup); 487 ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup; 488 489 return 0; 490 } 491 arch_initcall(rtas_msi_init); 492