root/arch/powerpc/platforms/pseries/msi.c

DEFINITIONS

1. rtas_change_msi
2. rtas_disable_msi
3. rtas_query_irq_number
4. rtas_teardown_msi_irqs
5. check_req
6. check_req_msi
7. check_req_msix
8. find_pe_total_msi
9. find_pe_dn
10. count_non_bridge_devices
11. count_spare_msis
12. msi_quota_for_device
13. check_msix_entries
14. rtas_hack_32bit_msi_gen2
15. rtas_setup_msi_irqs
16. rtas_msi_pci_irq_fixup
17. rtas_msi_init

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright 2006 Jake Moilanen <moilanen@austin.ibm.com>, IBM Corp.
   4  * Copyright 2006-2007 Michael Ellerman, IBM Corp.
   5  */
   6 
   7 #include <linux/device.h>
   8 #include <linux/irq.h>
   9 #include <linux/msi.h>
  10 
  11 #include <asm/rtas.h>
  12 #include <asm/hw_irq.h>
  13 #include <asm/ppc-pci.h>
  14 #include <asm/machdep.h>
  15 
  16 #include "pseries.h"
  17 
  18 static int query_token, change_token;
  19 
  20 #define RTAS_QUERY_FN           0
  21 #define RTAS_CHANGE_FN          1
  22 #define RTAS_RESET_FN           2
  23 #define RTAS_CHANGE_MSI_FN      3
  24 #define RTAS_CHANGE_MSIX_FN     4
  25 #define RTAS_CHANGE_32MSI_FN    5
  26 
  27 /* RTAS Helpers */
  28 
  29 static int rtas_change_msi(struct pci_dn *pdn, u32 func, u32 num_irqs)
  30 {
  31         u32 addr, seq_num, rtas_ret[3];
  32         unsigned long buid;
  33         int rc;
  34 
  35         addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
  36         buid = pdn->phb->buid;
  37 
  38         seq_num = 1;
  39         do {
  40                 if (func == RTAS_CHANGE_MSI_FN || func == RTAS_CHANGE_MSIX_FN ||
  41                     func == RTAS_CHANGE_32MSI_FN)
  42                         rc = rtas_call(change_token, 6, 4, rtas_ret, addr,
  43                                         BUID_HI(buid), BUID_LO(buid),
  44                                         func, num_irqs, seq_num);
  45                 else
  46                         rc = rtas_call(change_token, 6, 3, rtas_ret, addr,
  47                                         BUID_HI(buid), BUID_LO(buid),
  48                                         func, num_irqs, seq_num);
  49 
  50                 seq_num = rtas_ret[1];
  51         } while (rtas_busy_delay(rc));
  52 
  53         /*
  54          * If the RTAS call succeeded, return the number of irqs allocated.
  55          * If not, make sure we return a negative error code.
  56          */
  57         if (rc == 0)
  58                 rc = rtas_ret[0];
  59         else if (rc > 0)
  60                 rc = -rc;
  61 
  62         pr_debug("rtas_msi: ibm,change_msi(func=%d,num=%d), got %d rc = %d\n",
  63                  func, num_irqs, rtas_ret[0], rc);
  64 
  65         return rc;
  66 }
  67 
  68 static void rtas_disable_msi(struct pci_dev *pdev)
  69 {
  70         struct pci_dn *pdn;
  71 
  72         pdn = pci_get_pdn(pdev);
  73         if (!pdn)
  74                 return;
  75 
  76         /*
  77          * disabling MSI with the explicit interface also disables MSI-X
  78          */
  79         if (rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, 0) != 0) {
  80                 /* 
  81                  * may have failed because explicit interface is not
  82                  * present
  83                  */
  84                 if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) {
  85                         pr_debug("rtas_msi: Setting MSIs to 0 failed!\n");
  86                 }
  87         }
  88 }
  89 
  90 static int rtas_query_irq_number(struct pci_dn *pdn, int offset)
  91 {
  92         u32 addr, rtas_ret[2];
  93         unsigned long buid;
  94         int rc;
  95 
  96         addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
  97         buid = pdn->phb->buid;
  98 
  99         do {
 100                 rc = rtas_call(query_token, 4, 3, rtas_ret, addr,
 101                                BUID_HI(buid), BUID_LO(buid), offset);
 102         } while (rtas_busy_delay(rc));
 103 
 104         if (rc) {
 105                 pr_debug("rtas_msi: error (%d) querying source number\n", rc);
 106                 return rc;
 107         }
 108 
 109         return rtas_ret[0];
 110 }
 111 
 112 static void rtas_teardown_msi_irqs(struct pci_dev *pdev)
 113 {
 114         struct msi_desc *entry;
 115 
 116         for_each_pci_msi_entry(entry, pdev) {
 117                 if (!entry->irq)
 118                         continue;
 119 
 120                 irq_set_msi_desc(entry->irq, NULL);
 121                 irq_dispose_mapping(entry->irq);
 122         }
 123 
 124         rtas_disable_msi(pdev);
 125 }
 126 
 127 static int check_req(struct pci_dev *pdev, int nvec, char *prop_name)
 128 {
 129         struct device_node *dn;
 130         const __be32 *p;
 131         u32 req_msi;
 132 
 133         dn = pci_device_to_OF_node(pdev);
 134 
 135         p = of_get_property(dn, prop_name, NULL);
 136         if (!p) {
 137                 pr_debug("rtas_msi: No %s on %pOF\n", prop_name, dn);
 138                 return -ENOENT;
 139         }
 140 
 141         req_msi = be32_to_cpup(p);
 142         if (req_msi < nvec) {
 143                 pr_debug("rtas_msi: %s requests < %d MSIs\n", prop_name, nvec);
 144 
 145                 if (req_msi == 0) /* Be paranoid */
 146                         return -ENOSPC;
 147 
 148                 return req_msi;
 149         }
 150 
 151         return 0;
 152 }
 153 
 154 static int check_req_msi(struct pci_dev *pdev, int nvec)
 155 {
 156         return check_req(pdev, nvec, "ibm,req#msi");
 157 }
 158 
 159 static int check_req_msix(struct pci_dev *pdev, int nvec)
 160 {
 161         return check_req(pdev, nvec, "ibm,req#msi-x");
 162 }
 163 
 164 /* Quota calculation */
 165 
 166 static struct device_node *find_pe_total_msi(struct pci_dev *dev, int *total)
 167 {
 168         struct device_node *dn;
 169         const __be32 *p;
 170 
 171         dn = of_node_get(pci_device_to_OF_node(dev));
 172         while (dn) {
 173                 p = of_get_property(dn, "ibm,pe-total-#msi", NULL);
 174                 if (p) {
 175                         pr_debug("rtas_msi: found prop on dn %pOF\n",
 176                                 dn);
 177                         *total = be32_to_cpup(p);
 178                         return dn;
 179                 }
 180 
 181                 dn = of_get_next_parent(dn);
 182         }
 183 
 184         return NULL;
 185 }
 186 
 187 static struct device_node *find_pe_dn(struct pci_dev *dev, int *total)
 188 {
 189         struct device_node *dn;
 190         struct eeh_dev *edev;
 191 
 192         /* Found our PE and assume 8 at that point. */
 193 
 194         dn = pci_device_to_OF_node(dev);
 195         if (!dn)
 196                 return NULL;
 197 
 198         /* Get the top level device in the PE */
 199         edev = pdn_to_eeh_dev(PCI_DN(dn));
 200         if (edev->pe)
 201                 edev = list_first_entry(&edev->pe->edevs, struct eeh_dev,
 202                                         entry);
 203         dn = pci_device_to_OF_node(edev->pdev);
 204         if (!dn)
 205                 return NULL;
 206 
 207         /* We actually want the parent */
 208         dn = of_get_parent(dn);
 209         if (!dn)
 210                 return NULL;
 211 
 212         /* Hardcode of 8 for old firmwares */
 213         *total = 8;
 214         pr_debug("rtas_msi: using PE dn %pOF\n", dn);
 215 
 216         return dn;
 217 }
 218 
 219 struct msi_counts {
 220         struct device_node *requestor;
 221         int num_devices;
 222         int request;
 223         int quota;
 224         int spare;
 225         int over_quota;
 226 };
 227 
 228 static void *count_non_bridge_devices(struct device_node *dn, void *data)
 229 {
 230         struct msi_counts *counts = data;
 231         const __be32 *p;
 232         u32 class;
 233 
 234         pr_debug("rtas_msi: counting %pOF\n", dn);
 235 
 236         p = of_get_property(dn, "class-code", NULL);
 237         class = p ? be32_to_cpup(p) : 0;
 238 
 239         if ((class >> 8) != PCI_CLASS_BRIDGE_PCI)
 240                 counts->num_devices++;
 241 
 242         return NULL;
 243 }
 244 
 245 static void *count_spare_msis(struct device_node *dn, void *data)
 246 {
 247         struct msi_counts *counts = data;
 248         const __be32 *p;
 249         int req;
 250 
 251         if (dn == counts->requestor)
 252                 req = counts->request;
 253         else {
 254                 /* We don't know if a driver will try to use MSI or MSI-X,
 255                  * so we just have to punt and use the larger of the two. */
 256                 req = 0;
 257                 p = of_get_property(dn, "ibm,req#msi", NULL);
 258                 if (p)
 259                         req = be32_to_cpup(p);
 260 
 261                 p = of_get_property(dn, "ibm,req#msi-x", NULL);
 262                 if (p)
 263                         req = max(req, (int)be32_to_cpup(p));
 264         }
 265 
 266         if (req < counts->quota)
 267                 counts->spare += counts->quota - req;
 268         else if (req > counts->quota)
 269                 counts->over_quota++;
 270 
 271         return NULL;
 272 }
 273 
 274 static int msi_quota_for_device(struct pci_dev *dev, int request)
 275 {
 276         struct device_node *pe_dn;
 277         struct msi_counts counts;
 278         int total;
 279 
 280         pr_debug("rtas_msi: calc quota for %s, request %d\n", pci_name(dev),
 281                   request);
 282 
 283         pe_dn = find_pe_total_msi(dev, &total);
 284         if (!pe_dn)
 285                 pe_dn = find_pe_dn(dev, &total);
 286 
 287         if (!pe_dn) {
 288                 pr_err("rtas_msi: couldn't find PE for %s\n", pci_name(dev));
 289                 goto out;
 290         }
 291 
 292         pr_debug("rtas_msi: found PE %pOF\n", pe_dn);
 293 
 294         memset(&counts, 0, sizeof(struct msi_counts));
 295 
 296         /* Work out how many devices we have below this PE */
 297         pci_traverse_device_nodes(pe_dn, count_non_bridge_devices, &counts);
 298 
 299         if (counts.num_devices == 0) {
 300                 pr_err("rtas_msi: found 0 devices under PE for %s\n",
 301                         pci_name(dev));
 302                 goto out;
 303         }
 304 
 305         counts.quota = total / counts.num_devices;
 306         if (request <= counts.quota)
 307                 goto out;
 308 
 309         /* else, we have some more calculating to do */
 310         counts.requestor = pci_device_to_OF_node(dev);
 311         counts.request = request;
 312         pci_traverse_device_nodes(pe_dn, count_spare_msis, &counts);
 313 
 314         /* If the quota isn't an integer multiple of the total, we can
 315          * use the remainder as spare MSIs for anyone that wants them. */
 316         counts.spare += total % counts.num_devices;
 317 
 318         /* Divide any spare by the number of over-quota requestors */
 319         if (counts.over_quota)
 320                 counts.quota += counts.spare / counts.over_quota;
 321 
 322         /* And finally clamp the request to the possibly adjusted quota */
 323         request = min(counts.quota, request);
 324 
 325         pr_debug("rtas_msi: request clamped to quota %d\n", request);
 326 out:
 327         of_node_put(pe_dn);
 328 
 329         return request;
 330 }
 331 
 332 static int check_msix_entries(struct pci_dev *pdev)
 333 {
 334         struct msi_desc *entry;
 335         int expected;
 336 
 337         /* There's no way for us to express to firmware that we want
 338          * a discontiguous, or non-zero based, range of MSI-X entries.
 339          * So we must reject such requests. */
 340 
 341         expected = 0;
 342         for_each_pci_msi_entry(entry, pdev) {
 343                 if (entry->msi_attrib.entry_nr != expected) {
 344                         pr_debug("rtas_msi: bad MSI-X entries.\n");
 345                         return -EINVAL;
 346                 }
 347                 expected++;
 348         }
 349 
 350         return 0;
 351 }
 352 
 353 static void rtas_hack_32bit_msi_gen2(struct pci_dev *pdev)
 354 {
 355         u32 addr_hi, addr_lo;
 356 
 357         /*
 358          * We should only get in here for IODA1 configs. This is based on the
 359          * fact that we using RTAS for MSIs, we don't have the 32 bit MSI RTAS
 360          * support, and we are in a PCIe Gen2 slot.
 361          */
 362         dev_info(&pdev->dev,
 363                  "rtas_msi: No 32 bit MSI firmware support, forcing 32 bit MSI\n");
 364         pci_read_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, &addr_hi);
 365         addr_lo = 0xffff0000 | ((addr_hi >> (48 - 32)) << 4);
 366         pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_LO, addr_lo);
 367         pci_write_config_dword(pdev, pdev->msi_cap + PCI_MSI_ADDRESS_HI, 0);
 368 }
 369 
 370 static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type)
 371 {
 372         struct pci_dn *pdn;
 373         int hwirq, virq, i, quota, rc;
 374         struct msi_desc *entry;
 375         struct msi_msg msg;
 376         int nvec = nvec_in;
 377         int use_32bit_msi_hack = 0;
 378 
 379         if (type == PCI_CAP_ID_MSIX)
 380                 rc = check_req_msix(pdev, nvec);
 381         else
 382                 rc = check_req_msi(pdev, nvec);
 383 
 384         if (rc)
 385                 return rc;
 386 
 387         quota = msi_quota_for_device(pdev, nvec);
 388 
 389         if (quota && quota < nvec)
 390                 return quota;
 391 
 392         if (type == PCI_CAP_ID_MSIX && check_msix_entries(pdev))
 393                 return -EINVAL;
 394 
 395         /*
 396          * Firmware currently refuse any non power of two allocation
 397          * so we round up if the quota will allow it.
 398          */
 399         if (type == PCI_CAP_ID_MSIX) {
 400                 int m = roundup_pow_of_two(nvec);
 401                 quota = msi_quota_for_device(pdev, m);
 402 
 403                 if (quota >= m)
 404                         nvec = m;
 405         }
 406 
 407         pdn = pci_get_pdn(pdev);
 408 
 409         /*
 410          * Try the new more explicit firmware interface, if that fails fall
 411          * back to the old interface. The old interface is known to never
 412          * return MSI-Xs.
 413          */
 414 again:
 415         if (type == PCI_CAP_ID_MSI) {
 416                 if (pdev->no_64bit_msi) {
 417                         rc = rtas_change_msi(pdn, RTAS_CHANGE_32MSI_FN, nvec);
 418                         if (rc < 0) {
 419                                 /*
 420                                  * We only want to run the 32 bit MSI hack below if
 421                                  * the max bus speed is Gen2 speed
 422                                  */
 423                                 if (pdev->bus->max_bus_speed != PCIE_SPEED_5_0GT)
 424                                         return rc;
 425 
 426                                 use_32bit_msi_hack = 1;
 427                         }
 428                 } else
 429                         rc = -1;
 430 
 431                 if (rc < 0)
 432                         rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec);
 433 
 434                 if (rc < 0) {
 435                         pr_debug("rtas_msi: trying the old firmware call.\n");
 436                         rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec);
 437                 }
 438 
 439                 if (use_32bit_msi_hack && rc > 0)
 440                         rtas_hack_32bit_msi_gen2(pdev);
 441         } else
 442                 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
 443 
 444         if (rc != nvec) {
 445                 if (nvec != nvec_in) {
 446                         nvec = nvec_in;
 447                         goto again;
 448                 }
 449                 pr_debug("rtas_msi: rtas_change_msi() failed\n");
 450                 return rc;
 451         }
 452 
 453         i = 0;
 454         for_each_pci_msi_entry(entry, pdev) {
 455                 hwirq = rtas_query_irq_number(pdn, i++);
 456                 if (hwirq < 0) {
 457                         pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
 458                         return hwirq;
 459                 }
 460 
 461                 virq = irq_create_mapping(NULL, hwirq);
 462 
 463                 if (!virq) {
 464                         pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
 465                         return -ENOSPC;
 466                 }
 467 
 468                 dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
 469                 irq_set_msi_desc(virq, entry);
 470 
 471                 /* Read config space back so we can restore after reset */
 472                 __pci_read_msi_msg(entry, &msg);
 473                 entry->msg = msg;
 474         }
 475 
 476         return 0;
 477 }
 478 
 479 static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
 480 {
 481         /* No LSI -> leave MSIs (if any) configured */
 482         if (!pdev->irq) {
 483                 dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n");
 484                 return;
 485         }
 486 
 487         /* No MSI -> MSIs can't have been assigned by fw, leave LSI */
 488         if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) {
 489                 dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n");
 490                 return;
 491         }
 492 
 493         dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n");
 494         rtas_disable_msi(pdev);
 495 }
 496 
 497 static int rtas_msi_init(void)
 498 {
 499         struct pci_controller *phb;
 500 
 501         query_token  = rtas_token("ibm,query-interrupt-source-number");
 502         change_token = rtas_token("ibm,change-msi");
 503 
 504         if ((query_token == RTAS_UNKNOWN_SERVICE) ||
 505                         (change_token == RTAS_UNKNOWN_SERVICE)) {
 506                 pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n");
 507                 return -1;
 508         }
 509 
 510         pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n");
 511 
 512         WARN_ON(pseries_pci_controller_ops.setup_msi_irqs);
 513         pseries_pci_controller_ops.setup_msi_irqs = rtas_setup_msi_irqs;
 514         pseries_pci_controller_ops.teardown_msi_irqs = rtas_teardown_msi_irqs;
 515 
 516         list_for_each_entry(phb, &hose_list, list_node) {
 517                 WARN_ON(phb->controller_ops.setup_msi_irqs);
 518                 phb->controller_ops.setup_msi_irqs = rtas_setup_msi_irqs;
 519                 phb->controller_ops.teardown_msi_irqs = rtas_teardown_msi_irqs;
 520         }
 521 
 522         WARN_ON(ppc_md.pci_irq_fixup);
 523         ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup;
 524 
 525         return 0;
 526 }
 527 machine_arch_initcall(pseries, rtas_msi_init);