hw/ppc/spapr_vio.c

   1 /*
   2  * QEMU sPAPR VIO code
   3  *
   4  * Copyright (c) 2010 David Gibson, IBM Corporation <dwg@au1.ibm.com>
   5  * Based on the s390 virtio bus code:
   6  * Copyright (c) 2009 Alexander Graf <agraf@suse.de>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include "hw/hw.h"
  23 #include "sysemu/sysemu.h"
  24 #include "hw/boards.h"
  25 #include "hw/loader.h"
  26 #include "elf.h"
  27 #include "hw/sysbus.h"
  28 #include "sysemu/kvm.h"
  29 #include "sysemu/device_tree.h"
  30 #include "kvm_ppc.h"
  31
  32 #include "hw/ppc/spapr.h"
  33 #include "hw/ppc/spapr_vio.h"
  34 #include "hw/ppc/xics.h"
  35
  36 #include <libfdt.h>
  37
  38 /* #define DEBUG_SPAPR */
  39
  40 #ifdef DEBUG_SPAPR
  41 #define DPRINTF(fmt, ...) \
  42     do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
  43 #else
  44 #define DPRINTF(fmt, ...) \
  45     do { } while (0)
  46 #endif
  47
  48 static Property spapr_vio_props[] = {
  49     DEFINE_PROP_UINT32("irq", VIOsPAPRDevice, irq, 0), \
  50     DEFINE_PROP_END_OF_LIST(),
  51 };
  52
  53 static char *spapr_vio_get_dev_name(DeviceState *qdev)
  54 {
  55     VIOsPAPRDevice *dev = VIO_SPAPR_DEVICE(qdev);
  56     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
  57     char *name;
  58
  59     /* Device tree style name device@reg */
  60     name = g_strdup_printf("%s@%x", pc->dt_name, dev->reg);
  61
  62     return name;
  63 }
  64
  65 static void spapr_vio_bus_class_init(ObjectClass *klass, void *data)
  66 {
  67     BusClass *k = BUS_CLASS(klass);
  68
  69     k->get_dev_path = spapr_vio_get_dev_name;
  70     k->get_fw_dev_path = spapr_vio_get_dev_name;
  71 }
  72
  73 static const TypeInfo spapr_vio_bus_info = {
  74     .name = TYPE_SPAPR_VIO_BUS,
  75     .parent = TYPE_BUS,
  76     .class_init = spapr_vio_bus_class_init,
  77     .instance_size = sizeof(VIOsPAPRBus),
  78 };
  79
  80 VIOsPAPRDevice *spapr_vio_find_by_reg(VIOsPAPRBus *bus, uint32_t reg)
  81 {
  82     BusChild *kid;
  83     VIOsPAPRDevice *dev = NULL;
  84
  85     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
  86         dev = (VIOsPAPRDevice *)kid->child;
  87         if (dev->reg == reg) {
  88             return dev;
  89         }
  90     }
  91
  92     return NULL;
  93 }
  94
  95 static int vio_make_devnode(VIOsPAPRDevice *dev,
  96                             void *fdt)
  97 {
  98     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
  99     int vdevice_off, node_off, ret;
 100     char *dt_name;
 101
 102     vdevice_off = fdt_path_offset(fdt, "/vdevice");
 103     if (vdevice_off < 0) {
 104         return vdevice_off;
 105     }
 106
 107     dt_name = spapr_vio_get_dev_name(DEVICE(dev));
 108     node_off = fdt_add_subnode(fdt, vdevice_off, dt_name);
 109     g_free(dt_name);
 110     if (node_off < 0) {
 111         return node_off;
 112     }
 113
 114     ret = fdt_setprop_cell(fdt, node_off, "reg", dev->reg);
 115     if (ret < 0) {
 116         return ret;
 117     }
 118
 119     if (pc->dt_type) {
 120         ret = fdt_setprop_string(fdt, node_off, "device_type",
 121                                  pc->dt_type);
 122         if (ret < 0) {
 123             return ret;
 124         }
 125     }
 126
 127     if (pc->dt_compatible) {
 128         ret = fdt_setprop_string(fdt, node_off, "compatible",
 129                                  pc->dt_compatible);
 130         if (ret < 0) {
 131             return ret;
 132         }
 133     }
 134
 135     if (dev->irq) {
 136         uint32_t ints_prop[] = {cpu_to_be32(dev->irq), 0};
 137
 138         ret = fdt_setprop(fdt, node_off, "interrupts", ints_prop,
 139                           sizeof(ints_prop));
 140         if (ret < 0) {
 141             return ret;
 142         }
 143     }
 144
 145     ret = spapr_tcet_dma_dt(fdt, node_off, "ibm,my-dma-window", dev->tcet);
 146     if (ret < 0) {
 147         return ret;
 148     }
 149
 150     if (pc->devnode) {
 151         ret = (pc->devnode)(dev, fdt, node_off);
 152         if (ret < 0) {
 153             return ret;
 154         }
 155     }
 156
 157     return node_off;
 158 }
 159
 160 /*
 161  * CRQ handling
 162  */
 163 static target_ulong h_reg_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 164                               target_ulong opcode, target_ulong *args)
 165 {
 166     target_ulong reg = args[0];
 167     target_ulong queue_addr = args[1];
 168     target_ulong queue_len = args[2];
 169     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
 170
 171     if (!dev) {
 172         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
 173         return H_PARAMETER;
 174     }
 175
 176     /* We can't grok a queue size bigger than 256M for now */
 177     if (queue_len < 0x1000 || queue_len > 0x10000000) {
 178         hcall_dprintf("Queue size too small or too big (0x" TARGET_FMT_lx
 179                       ")\n", queue_len);
 180         return H_PARAMETER;
 181     }
 182
 183     /* Check queue alignment */
 184     if (queue_addr & 0xfff) {
 185         hcall_dprintf("Queue not aligned (0x" TARGET_FMT_lx ")\n", queue_addr);
 186         return H_PARAMETER;
 187     }
 188
 189     /* Check if device supports CRQs */
 190     if (!dev->crq.SendFunc) {
 191         hcall_dprintf("Device does not support CRQ\n");
 192         return H_NOT_FOUND;
 193     }
 194
 195     /* Already a queue ? */
 196     if (dev->crq.qsize) {
 197         hcall_dprintf("CRQ already registered\n");
 198         return H_RESOURCE;
 199     }
 200     dev->crq.qladdr = queue_addr;
 201     dev->crq.qsize = queue_len;
 202     dev->crq.qnext = 0;
 203
 204     DPRINTF("CRQ for dev 0x" TARGET_FMT_lx " registered at 0x"
 205             TARGET_FMT_lx "/0x" TARGET_FMT_lx "\n",
 206             reg, queue_addr, queue_len);
 207     return H_SUCCESS;
 208 }
 209
 210 static target_ulong free_crq(VIOsPAPRDevice *dev)
 211 {
 212     dev->crq.qladdr = 0;
 213     dev->crq.qsize = 0;
 214     dev->crq.qnext = 0;
 215
 216     DPRINTF("CRQ for dev 0x%" PRIx32 " freed\n", dev->reg);
 217
 218     return H_SUCCESS;
 219 }
 220
 221 static target_ulong h_free_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 222                                target_ulong opcode, target_ulong *args)
 223 {
 224     target_ulong reg = args[0];
 225     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
 226
 227     if (!dev) {
 228         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
 229         return H_PARAMETER;
 230     }
 231
 232     return free_crq(dev);
 233 }
 234
 235 static target_ulong h_send_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 236                                target_ulong opcode, target_ulong *args)
 237 {
 238     target_ulong reg = args[0];
 239     target_ulong msg_hi = args[1];
 240     target_ulong msg_lo = args[2];
 241     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
 242     uint64_t crq_mangle[2];
 243
 244     if (!dev) {
 245         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
 246         return H_PARAMETER;
 247     }
 248     crq_mangle[0] = cpu_to_be64(msg_hi);
 249     crq_mangle[1] = cpu_to_be64(msg_lo);
 250
 251     if (dev->crq.SendFunc) {
 252         return dev->crq.SendFunc(dev, (uint8_t *)crq_mangle);
 253     }
 254
 255     return H_HARDWARE;
 256 }
 257
 258 static target_ulong h_enable_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 259                                  target_ulong opcode, target_ulong *args)
 260 {
 261     target_ulong reg = args[0];
 262     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
 263
 264     if (!dev) {
 265         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
 266         return H_PARAMETER;
 267     }
 268
 269     return 0;
 270 }
 271
 272 /* Returns negative error, 0 success, or positive: queue full */
 273 int spapr_vio_send_crq(VIOsPAPRDevice *dev, uint8_t *crq)
 274 {
 275     int rc;
 276     uint8_t byte;
 277
 278     if (!dev->crq.qsize) {
 279         fprintf(stderr, "spapr_vio_send_creq on uninitialized queue\n");
 280         return -1;
 281     }
 282
 283     /* Maybe do a fast path for KVM just writing to the pages */
 284     rc = spapr_vio_dma_read(dev, dev->crq.qladdr + dev->crq.qnext, &byte, 1);
 285     if (rc) {
 286         return rc;
 287     }
 288     if (byte != 0) {
 289         return 1;
 290     }
 291
 292     rc = spapr_vio_dma_write(dev, dev->crq.qladdr + dev->crq.qnext + 8,
 293                              &crq[8], 8);
 294     if (rc) {
 295         return rc;
 296     }
 297
 298     kvmppc_eieio();
 299
 300     rc = spapr_vio_dma_write(dev, dev->crq.qladdr + dev->crq.qnext, crq, 8);
 301     if (rc) {
 302         return rc;
 303     }
 304
 305     dev->crq.qnext = (dev->crq.qnext + 16) % dev->crq.qsize;
 306
 307     if (dev->signal_state & 1) {
 308         qemu_irq_pulse(spapr_vio_qirq(dev));
 309     }
 310
 311     return 0;
 312 }
 313
 314 /* "quiesce" handling */
 315
 316 static void spapr_vio_quiesce_one(VIOsPAPRDevice *dev)
 317 {
 318     if (dev->tcet) {
 319         device_reset(DEVICE(dev->tcet));
 320     }
 321     free_crq(dev);
 322 }
 323
 324 void spapr_vio_set_bypass(VIOsPAPRDevice *dev, bool bypass)
 325 {
 326     if (!dev->tcet) {
 327         return;
 328     }
 329
 330     memory_region_set_enabled(&dev->mrbypass, bypass);
 331     memory_region_set_enabled(spapr_tce_get_iommu(dev->tcet), !bypass);
 332
 333     dev->tcet->bypass = bypass;
 334 }
 335
 336 static void rtas_set_tce_bypass(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 337                                 uint32_t token,
 338                                 uint32_t nargs, target_ulong args,
 339                                 uint32_t nret, target_ulong rets)
 340 {
 341     VIOsPAPRBus *bus = spapr->vio_bus;
 342     VIOsPAPRDevice *dev;
 343     uint32_t unit, enable;
 344
 345     if (nargs != 2) {
 346         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
 347         return;
 348     }
 349     unit = rtas_ld(args, 0);
 350     enable = rtas_ld(args, 1);
 351     dev = spapr_vio_find_by_reg(bus, unit);
 352     if (!dev) {
 353         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
 354         return;
 355     }
 356
 357     if (!dev->tcet) {
 358         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
 359         return;
 360     }
 361
 362     spapr_vio_set_bypass(dev, !!enable);
 363
 364     rtas_st(rets, 0, RTAS_OUT_SUCCESS);
 365 }
 366
 367 static void rtas_quiesce(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 368                          uint32_t token,
 369                          uint32_t nargs, target_ulong args,
 370                          uint32_t nret, target_ulong rets)
 371 {
 372     VIOsPAPRBus *bus = spapr->vio_bus;
 373     BusChild *kid;
 374     VIOsPAPRDevice *dev = NULL;
 375
 376     if (nargs != 0) {
 377         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
 378         return;
 379     }
 380
 381     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
 382         dev = (VIOsPAPRDevice *)kid->child;
 383         spapr_vio_quiesce_one(dev);
 384     }
 385
 386     rtas_st(rets, 0, RTAS_OUT_SUCCESS);
 387 }
 388
 389 static VIOsPAPRDevice *reg_conflict(VIOsPAPRDevice *dev)
 390 {
 391     VIOsPAPRBus *bus = DO_UPCAST(VIOsPAPRBus, bus, dev->qdev.parent_bus);
 392     BusChild *kid;
 393     VIOsPAPRDevice *other;
 394
 395     /*
 396      * Check for a device other than the given one which is already
 397      * using the requested address. We have to open code this because
 398      * the given dev might already be in the list.
 399      */
 400     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
 401         other = VIO_SPAPR_DEVICE(kid->child);
 402
 403         if (other != dev && other->reg == dev->reg) {
 404             return other;
 405         }
 406     }
 407
 408     return 0;
 409 }
 410
 411 static void spapr_vio_busdev_reset(DeviceState *qdev)
 412 {
 413     VIOsPAPRDevice *dev = VIO_SPAPR_DEVICE(qdev);
 414     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
 415
 416     /* Shut down the request queue and TCEs if necessary */
 417     spapr_vio_quiesce_one(dev);
 418
 419     dev->signal_state = 0;
 420
 421     spapr_vio_set_bypass(dev, false);
 422     if (pc->reset) {
 423         pc->reset(dev);
 424     }
 425 }
 426
 427 static void spapr_vio_busdev_realize(DeviceState *qdev, Error **errp)
 428 {
 429     sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
 430     VIOsPAPRDevice *dev = (VIOsPAPRDevice *)qdev;
 431     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
 432     char *id;
 433
 434     if (dev->reg != -1) {
 435         /*
 436          * Explicitly assigned address, just verify that no-one else
 437          * is using it.  other mechanism). We have to open code this
 438          * rather than using spapr_vio_find_by_reg() because sdev
 439          * itself is already in the list.
 440          */
 441         VIOsPAPRDevice *other = reg_conflict(dev);
 442
 443         if (other) {
 444             error_setg(errp, "%s and %s devices conflict at address %#x",
 445                        object_get_typename(OBJECT(qdev)),
 446                        object_get_typename(OBJECT(&other->qdev)),
 447                        dev->reg);
 448             return;
 449         }
 450     } else {
 451         /* Need to assign an address */
 452         VIOsPAPRBus *bus = DO_UPCAST(VIOsPAPRBus, bus, dev->qdev.parent_bus);
 453
 454         do {
 455             dev->reg = bus->next_reg++;
 456         } while (reg_conflict(dev));
 457     }
 458
 459     /* Don't overwrite ids assigned on the command line */
 460     if (!dev->qdev.id) {
 461         id = spapr_vio_get_dev_name(DEVICE(dev));
 462         dev->qdev.id = id;
 463     }
 464
 465     dev->irq = xics_alloc(spapr->icp, 0, dev->irq, false);
 466     if (!dev->irq) {
 467         error_setg(errp, "can't allocate IRQ");
 468         return;
 469     }
 470
 471     if (pc->rtce_window_size) {
 472         uint32_t liobn = SPAPR_VIO_LIOBN(dev->reg);
 473
 474         memory_region_init(&dev->mrroot, OBJECT(dev), "iommu-spapr-root",
 475                            ram_size);
 476         memory_region_init_alias(&dev->mrbypass, OBJECT(dev),
 477                                  "iommu-spapr-bypass", get_system_memory(),
 478                                  0, ram_size);
 479         memory_region_add_subregion_overlap(&dev->mrroot, 0, &dev->mrbypass, 1);
 480         address_space_init(&dev->as, &dev->mrroot, qdev->id);
 481
 482         dev->tcet = spapr_tce_new_table(qdev, liobn,
 483                                         0,
 484                                         SPAPR_TCE_PAGE_SHIFT,
 485                                         pc->rtce_window_size >>
 486                                         SPAPR_TCE_PAGE_SHIFT, false);
 487         dev->tcet->vdev = dev;
 488         memory_region_add_subregion_overlap(&dev->mrroot, 0,
 489                                             spapr_tce_get_iommu(dev->tcet), 2);
 490     }
 491
 492     pc->realize(dev, errp);
 493 }
 494
 495 static target_ulong h_vio_signal(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 496                                  target_ulong opcode,
 497                                  target_ulong *args)
 498 {
 499     target_ulong reg = args[0];
 500     target_ulong mode = args[1];
 501     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
 502     VIOsPAPRDeviceClass *pc;
 503
 504     if (!dev) {
 505         return H_PARAMETER;
 506     }
 507
 508     pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
 509
 510     if (mode & ~pc->signal_mask) {
 511         return H_PARAMETER;
 512     }
 513
 514     dev->signal_state = mode;
 515
 516     return H_SUCCESS;
 517 }
 518
 519 VIOsPAPRBus *spapr_vio_bus_init(void)
 520 {
 521     VIOsPAPRBus *bus;
 522     BusState *qbus;
 523     DeviceState *dev;
 524
 525     /* Create bridge device */
 526     dev = qdev_create(NULL, "spapr-vio-bridge");
 527     qdev_init_nofail(dev);
 528
 529     /* Create bus on bridge device */
 530
 531     qbus = qbus_create(TYPE_SPAPR_VIO_BUS, dev, "spapr-vio");
 532     bus = DO_UPCAST(VIOsPAPRBus, bus, qbus);
 533     bus->next_reg = 0x71000000;
 534
 535     /* hcall-vio */
 536     spapr_register_hypercall(H_VIO_SIGNAL, h_vio_signal);
 537
 538     /* hcall-crq */
 539     spapr_register_hypercall(H_REG_CRQ, h_reg_crq);
 540     spapr_register_hypercall(H_FREE_CRQ, h_free_crq);
 541     spapr_register_hypercall(H_SEND_CRQ, h_send_crq);
 542     spapr_register_hypercall(H_ENABLE_CRQ, h_enable_crq);
 543
 544     /* RTAS calls */
 545     spapr_rtas_register(RTAS_IBM_SET_TCE_BYPASS, "ibm,set-tce-bypass",
 546                         rtas_set_tce_bypass);
 547     spapr_rtas_register(RTAS_QUIESCE, "quiesce", rtas_quiesce);
 548
 549     return bus;
 550 }
 551
 552 /* Represents sPAPR hcall VIO devices */
 553
 554 static int spapr_vio_bridge_init(SysBusDevice *dev)
 555 {
 556     /* nothing */
 557     return 0;
 558 }
 559
 560 static void spapr_vio_bridge_class_init(ObjectClass *klass, void *data)
 561 {
 562     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 563     DeviceClass *dc = DEVICE_CLASS(klass);
 564
 565     dc->fw_name = "vdevice";
 566     k->init = spapr_vio_bridge_init;
 567 }
 568
 569 static const TypeInfo spapr_vio_bridge_info = {
 570     .name          = "spapr-vio-bridge",
 571     .parent        = TYPE_SYS_BUS_DEVICE,
 572     .instance_size = sizeof(SysBusDevice),
 573     .class_init    = spapr_vio_bridge_class_init,
 574 };
 575
 576 const VMStateDescription vmstate_spapr_vio = {
 577     .name = "spapr_vio",
 578     .version_id = 1,
 579     .minimum_version_id = 1,
 580     .fields = (VMStateField[]) {
 581         /* Sanity check */
 582         VMSTATE_UINT32_EQUAL(reg, VIOsPAPRDevice),
 583         VMSTATE_UINT32_EQUAL(irq, VIOsPAPRDevice),
 584
 585         /* General VIO device state */
 586         VMSTATE_UINTTL(signal_state, VIOsPAPRDevice),
 587         VMSTATE_UINT64(crq.qladdr, VIOsPAPRDevice),
 588         VMSTATE_UINT32(crq.qsize, VIOsPAPRDevice),
 589         VMSTATE_UINT32(crq.qnext, VIOsPAPRDevice),
 590
 591         VMSTATE_END_OF_LIST()
 592     },
 593 };
 594
 595 static void vio_spapr_device_class_init(ObjectClass *klass, void *data)
 596 {
 597     DeviceClass *k = DEVICE_CLASS(klass);
 598     k->realize = spapr_vio_busdev_realize;
 599     k->reset = spapr_vio_busdev_reset;
 600     k->bus_type = TYPE_SPAPR_VIO_BUS;
 601     k->props = spapr_vio_props;
 602 }
 603
 604 static const TypeInfo spapr_vio_type_info = {
 605     .name = TYPE_VIO_SPAPR_DEVICE,
 606     .parent = TYPE_DEVICE,
 607     .instance_size = sizeof(VIOsPAPRDevice),
 608     .abstract = true,
 609     .class_size = sizeof(VIOsPAPRDeviceClass),
 610     .class_init = vio_spapr_device_class_init,
 611 };
 612
 613 static void spapr_vio_register_types(void)
 614 {
 615     type_register_static(&spapr_vio_bus_info);
 616     type_register_static(&spapr_vio_bridge_info);
 617     type_register_static(&spapr_vio_type_info);
 618 }
 619
 620 type_init(spapr_vio_register_types)
 621
 622 static int compare_reg(const void *p1, const void *p2)
 623 {
 624     VIOsPAPRDevice const *dev1, *dev2;
 625
 626     dev1 = (VIOsPAPRDevice *)*(DeviceState **)p1;
 627     dev2 = (VIOsPAPRDevice *)*(DeviceState **)p2;
 628
 629     if (dev1->reg < dev2->reg) {
 630         return -1;
 631     }
 632     if (dev1->reg == dev2->reg) {
 633         return 0;
 634     }
 635
 636     /* dev1->reg > dev2->reg */
 637     return 1;
 638 }
 639
 640 int spapr_populate_vdevice(VIOsPAPRBus *bus, void *fdt)
 641 {
 642     DeviceState *qdev, **qdevs;
 643     BusChild *kid;
 644     int i, num, ret = 0;
 645
 646     /* Count qdevs on the bus list */
 647     num = 0;
 648     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
 649         num++;
 650     }
 651
 652     /* Copy out into an array of pointers */
 653     qdevs = g_malloc(sizeof(qdev) * num);
 654     num = 0;
 655     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
 656         qdevs[num++] = kid->child;
 657     }
 658
 659     /* Sort the array */
 660     qsort(qdevs, num, sizeof(qdev), compare_reg);
 661
 662     /* Hack alert. Give the devices to libfdt in reverse order, we happen
 663      * to know that will mean they are in forward order in the tree. */
 664     for (i = num - 1; i >= 0; i--) {
 665         VIOsPAPRDevice *dev = (VIOsPAPRDevice *)(qdevs[i]);
 666
 667         ret = vio_make_devnode(dev, fdt);
 668
 669         if (ret < 0) {
 670             goto out;
 671         }
 672     }
 673
 674     ret = 0;
 675 out:
 676     g_free(qdevs);
 677
 678     return ret;
 679 }
 680
 681 int spapr_populate_chosen_stdout(void *fdt, VIOsPAPRBus *bus)
 682 {
 683     VIOsPAPRDevice *dev;
 684     char *name, *path;
 685     int ret, offset;
 686
 687     dev = spapr_vty_get_default(bus);
 688     if (!dev)
 689         return 0;
 690
 691     offset = fdt_path_offset(fdt, "/chosen");
 692     if (offset < 0) {
 693         return offset;
 694     }
 695
 696     name = spapr_vio_get_dev_name(DEVICE(dev));
 697     path = g_strdup_printf("/vdevice/%s", name);
 698
 699     ret = fdt_setprop_string(fdt, offset, "linux,stdout-path", path);
 700
 701     g_free(name);
 702     g_free(path);
 703
 704     return ret;
 705 }