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