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 "qapi/error.h"
  24 #include "hw/hw.h"
  25 #include "qemu/log.h"
  26 #include "sysemu/sysemu.h"
  27 #include "hw/boards.h"
  28 #include "hw/loader.h"
  29 #include "elf.h"
  30 #include "hw/sysbus.h"
  31 #include "sysemu/kvm.h"
  32 #include "sysemu/device_tree.h"
  33 #include "kvm_ppc.h"
  34
  35 #include "hw/ppc/spapr.h"
  36 #include "hw/ppc/spapr_vio.h"
  37 #include "hw/ppc/xics.h"
  38
  39 #include <libfdt.h>
  40
  41 /* #define DEBUG_SPAPR */
  42
  43 #ifdef DEBUG_SPAPR
  44 #define DPRINTF(fmt, ...) \
  45     do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
  46 #else
  47 #define DPRINTF(fmt, ...) \
  48     do { } while (0)
  49 #endif
  50
  51 static Property spapr_vio_props[] = {
  52     DEFINE_PROP_UINT32("irq", VIOsPAPRDevice, irq, 0), \
  53     DEFINE_PROP_END_OF_LIST(),
  54 };
  55
  56 static char *spapr_vio_get_dev_name(DeviceState *qdev)
  57 {
  58     VIOsPAPRDevice *dev = VIO_SPAPR_DEVICE(qdev);
  59     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
  60     char *name;
  61
  62     /* Device tree style name device@reg */
  63     name = g_strdup_printf("%s@%x", pc->dt_name, dev->reg);
  64
  65     return name;
  66 }
  67
  68 static void spapr_vio_bus_class_init(ObjectClass *klass, void *data)
  69 {
  70     BusClass *k = BUS_CLASS(klass);
  71
  72     k->get_dev_path = spapr_vio_get_dev_name;
  73     k->get_fw_dev_path = spapr_vio_get_dev_name;
  74 }
  75
  76 static const TypeInfo spapr_vio_bus_info = {
  77     .name = TYPE_SPAPR_VIO_BUS,
  78     .parent = TYPE_BUS,
  79     .class_init = spapr_vio_bus_class_init,
  80     .instance_size = sizeof(VIOsPAPRBus),
  81 };
  82
  83 VIOsPAPRDevice *spapr_vio_find_by_reg(VIOsPAPRBus *bus, uint32_t reg)
  84 {
  85     BusChild *kid;
  86     VIOsPAPRDevice *dev = NULL;
  87
  88     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
  89         dev = (VIOsPAPRDevice *)kid->child;
  90         if (dev->reg == reg) {
  91             return dev;
  92         }
  93     }
  94
  95     return NULL;
  96 }
  97
  98 static int vio_make_devnode(VIOsPAPRDevice *dev,
  99                             void *fdt)
 100 {
 101     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
 102     int vdevice_off, node_off, ret;
 103     char *dt_name;
 104
 105     vdevice_off = fdt_path_offset(fdt, "/vdevice");
 106     if (vdevice_off < 0) {
 107         return vdevice_off;
 108     }
 109
 110     dt_name = spapr_vio_get_dev_name(DEVICE(dev));
 111     node_off = fdt_add_subnode(fdt, vdevice_off, dt_name);
 112     g_free(dt_name);
 113     if (node_off < 0) {
 114         return node_off;
 115     }
 116
 117     ret = fdt_setprop_cell(fdt, node_off, "reg", dev->reg);
 118     if (ret < 0) {
 119         return ret;
 120     }
 121
 122     if (pc->dt_type) {
 123         ret = fdt_setprop_string(fdt, node_off, "device_type",
 124                                  pc->dt_type);
 125         if (ret < 0) {
 126             return ret;
 127         }
 128     }
 129
 130     if (pc->dt_compatible) {
 131         ret = fdt_setprop_string(fdt, node_off, "compatible",
 132                                  pc->dt_compatible);
 133         if (ret < 0) {
 134             return ret;
 135         }
 136     }
 137
 138     if (dev->irq) {
 139         uint32_t ints_prop[] = {cpu_to_be32(dev->irq), 0};
 140
 141         ret = fdt_setprop(fdt, node_off, "interrupts", ints_prop,
 142                           sizeof(ints_prop));
 143         if (ret < 0) {
 144             return ret;
 145         }
 146     }
 147
 148     ret = spapr_tcet_dma_dt(fdt, node_off, "ibm,my-dma-window", dev->tcet);
 149     if (ret < 0) {
 150         return ret;
 151     }
 152
 153     if (pc->devnode) {
 154         ret = (pc->devnode)(dev, fdt, node_off);
 155         if (ret < 0) {
 156             return ret;
 157         }
 158     }
 159
 160     return node_off;
 161 }
 162
 163 /*
 164  * CRQ handling
 165  */
 166 static target_ulong h_reg_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 167                               target_ulong opcode, target_ulong *args)
 168 {
 169     target_ulong reg = args[0];
 170     target_ulong queue_addr = args[1];
 171     target_ulong queue_len = args[2];
 172     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
 173
 174     if (!dev) {
 175         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
 176         return H_PARAMETER;
 177     }
 178
 179     /* We can't grok a queue size bigger than 256M for now */
 180     if (queue_len < 0x1000 || queue_len > 0x10000000) {
 181         hcall_dprintf("Queue size too small or too big (0x" TARGET_FMT_lx
 182                       ")\n", queue_len);
 183         return H_PARAMETER;
 184     }
 185
 186     /* Check queue alignment */
 187     if (queue_addr & 0xfff) {
 188         hcall_dprintf("Queue not aligned (0x" TARGET_FMT_lx ")\n", queue_addr);
 189         return H_PARAMETER;
 190     }
 191
 192     /* Check if device supports CRQs */
 193     if (!dev->crq.SendFunc) {
 194         hcall_dprintf("Device does not support CRQ\n");
 195         return H_NOT_FOUND;
 196     }
 197
 198     /* Already a queue ? */
 199     if (dev->crq.qsize) {
 200         hcall_dprintf("CRQ already registered\n");
 201         return H_RESOURCE;
 202     }
 203     dev->crq.qladdr = queue_addr;
 204     dev->crq.qsize = queue_len;
 205     dev->crq.qnext = 0;
 206
 207     DPRINTF("CRQ for dev 0x" TARGET_FMT_lx " registered at 0x"
 208             TARGET_FMT_lx "/0x" TARGET_FMT_lx "\n",
 209             reg, queue_addr, queue_len);
 210     return H_SUCCESS;
 211 }
 212
 213 static target_ulong free_crq(VIOsPAPRDevice *dev)
 214 {
 215     dev->crq.qladdr = 0;
 216     dev->crq.qsize = 0;
 217     dev->crq.qnext = 0;
 218
 219     DPRINTF("CRQ for dev 0x%" PRIx32 " freed\n", dev->reg);
 220
 221     return H_SUCCESS;
 222 }
 223
 224 static target_ulong h_free_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 225                                target_ulong opcode, target_ulong *args)
 226 {
 227     target_ulong reg = args[0];
 228     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
 229
 230     if (!dev) {
 231         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
 232         return H_PARAMETER;
 233     }
 234
 235     return free_crq(dev);
 236 }
 237
 238 static target_ulong h_send_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 239                                target_ulong opcode, target_ulong *args)
 240 {
 241     target_ulong reg = args[0];
 242     target_ulong msg_hi = args[1];
 243     target_ulong msg_lo = args[2];
 244     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
 245     uint64_t crq_mangle[2];
 246
 247     if (!dev) {
 248         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
 249         return H_PARAMETER;
 250     }
 251     crq_mangle[0] = cpu_to_be64(msg_hi);
 252     crq_mangle[1] = cpu_to_be64(msg_lo);
 253
 254     if (dev->crq.SendFunc) {
 255         return dev->crq.SendFunc(dev, (uint8_t *)crq_mangle);
 256     }
 257
 258     return H_HARDWARE;
 259 }
 260
 261 static target_ulong h_enable_crq(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 262                                  target_ulong opcode, target_ulong *args)
 263 {
 264     target_ulong reg = args[0];
 265     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
 266
 267     if (!dev) {
 268         hcall_dprintf("Unit 0x" TARGET_FMT_lx " does not exist\n", reg);
 269         return H_PARAMETER;
 270     }
 271
 272     return 0;
 273 }
 274
 275 /* Returns negative error, 0 success, or positive: queue full */
 276 int spapr_vio_send_crq(VIOsPAPRDevice *dev, uint8_t *crq)
 277 {
 278     int rc;
 279     uint8_t byte;
 280
 281     if (!dev->crq.qsize) {
 282         fprintf(stderr, "spapr_vio_send_creq on uninitialized queue\n");
 283         return -1;
 284     }
 285
 286     /* Maybe do a fast path for KVM just writing to the pages */
 287     rc = spapr_vio_dma_read(dev, dev->crq.qladdr + dev->crq.qnext, &byte, 1);
 288     if (rc) {
 289         return rc;
 290     }
 291     if (byte != 0) {
 292         return 1;
 293     }
 294
 295     rc = spapr_vio_dma_write(dev, dev->crq.qladdr + dev->crq.qnext + 8,
 296                              &crq[8], 8);
 297     if (rc) {
 298         return rc;
 299     }
 300
 301     kvmppc_eieio();
 302
 303     rc = spapr_vio_dma_write(dev, dev->crq.qladdr + dev->crq.qnext, crq, 8);
 304     if (rc) {
 305         return rc;
 306     }
 307
 308     dev->crq.qnext = (dev->crq.qnext + 16) % dev->crq.qsize;
 309
 310     if (dev->signal_state & 1) {
 311         qemu_irq_pulse(spapr_vio_qirq(dev));
 312     }
 313
 314     return 0;
 315 }
 316
 317 /* "quiesce" handling */
 318
 319 static void spapr_vio_quiesce_one(VIOsPAPRDevice *dev)
 320 {
 321     if (dev->tcet) {
 322         device_reset(DEVICE(dev->tcet));
 323     }
 324     free_crq(dev);
 325 }
 326
 327 void spapr_vio_set_bypass(VIOsPAPRDevice *dev, bool bypass)
 328 {
 329     if (!dev->tcet) {
 330         return;
 331     }
 332
 333     memory_region_set_enabled(&dev->mrbypass, bypass);
 334     memory_region_set_enabled(spapr_tce_get_iommu(dev->tcet), !bypass);
 335
 336     dev->tcet->bypass = bypass;
 337 }
 338
 339 static void rtas_set_tce_bypass(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 340                                 uint32_t token,
 341                                 uint32_t nargs, target_ulong args,
 342                                 uint32_t nret, target_ulong rets)
 343 {
 344     VIOsPAPRBus *bus = spapr->vio_bus;
 345     VIOsPAPRDevice *dev;
 346     uint32_t unit, enable;
 347
 348     if (nargs != 2) {
 349         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
 350         return;
 351     }
 352     unit = rtas_ld(args, 0);
 353     enable = rtas_ld(args, 1);
 354     dev = spapr_vio_find_by_reg(bus, unit);
 355     if (!dev) {
 356         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
 357         return;
 358     }
 359
 360     if (!dev->tcet) {
 361         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
 362         return;
 363     }
 364
 365     spapr_vio_set_bypass(dev, !!enable);
 366
 367     rtas_st(rets, 0, RTAS_OUT_SUCCESS);
 368 }
 369
 370 static void rtas_quiesce(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 371                          uint32_t token,
 372                          uint32_t nargs, target_ulong args,
 373                          uint32_t nret, target_ulong rets)
 374 {
 375     VIOsPAPRBus *bus = spapr->vio_bus;
 376     BusChild *kid;
 377     VIOsPAPRDevice *dev = NULL;
 378
 379     if (nargs != 0) {
 380         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
 381         return;
 382     }
 383
 384     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
 385         dev = (VIOsPAPRDevice *)kid->child;
 386         spapr_vio_quiesce_one(dev);
 387     }
 388
 389     rtas_st(rets, 0, RTAS_OUT_SUCCESS);
 390 }
 391
 392 static VIOsPAPRDevice *reg_conflict(VIOsPAPRDevice *dev)
 393 {
 394     VIOsPAPRBus *bus = SPAPR_VIO_BUS(dev->qdev.parent_bus);
 395     BusChild *kid;
 396     VIOsPAPRDevice *other;
 397
 398     /*
 399      * Check for a device other than the given one which is already
 400      * using the requested address. We have to open code this because
 401      * the given dev might already be in the list.
 402      */
 403     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
 404         other = VIO_SPAPR_DEVICE(kid->child);
 405
 406         if (other != dev && other->reg == dev->reg) {
 407             return other;
 408         }
 409     }
 410
 411     return 0;
 412 }
 413
 414 static void spapr_vio_busdev_reset(DeviceState *qdev)
 415 {
 416     VIOsPAPRDevice *dev = VIO_SPAPR_DEVICE(qdev);
 417     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
 418
 419     /* Shut down the request queue and TCEs if necessary */
 420     spapr_vio_quiesce_one(dev);
 421
 422     dev->signal_state = 0;
 423
 424     spapr_vio_set_bypass(dev, false);
 425     if (pc->reset) {
 426         pc->reset(dev);
 427     }
 428 }
 429
 430 static void spapr_vio_busdev_realize(DeviceState *qdev, Error **errp)
 431 {
 432     sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
 433     VIOsPAPRDevice *dev = (VIOsPAPRDevice *)qdev;
 434     VIOsPAPRDeviceClass *pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
 435     char *id;
 436     Error *local_err = NULL;
 437
 438     if (dev->reg != -1) {
 439         /*
 440          * Explicitly assigned address, just verify that no-one else
 441          * is using it.  other mechanism). We have to open code this
 442          * rather than using spapr_vio_find_by_reg() because sdev
 443          * itself is already in the list.
 444          */
 445         VIOsPAPRDevice *other = reg_conflict(dev);
 446
 447         if (other) {
 448             error_setg(errp, "%s and %s devices conflict at address %#x",
 449                        object_get_typename(OBJECT(qdev)),
 450                        object_get_typename(OBJECT(&other->qdev)),
 451                        dev->reg);
 452             return;
 453         }
 454     } else {
 455         /* Need to assign an address */
 456         VIOsPAPRBus *bus = SPAPR_VIO_BUS(dev->qdev.parent_bus);
 457
 458         do {
 459             dev->reg = bus->next_reg++;
 460         } while (reg_conflict(dev));
 461     }
 462
 463     /* Don't overwrite ids assigned on the command line */
 464     if (!dev->qdev.id) {
 465         id = spapr_vio_get_dev_name(DEVICE(dev));
 466         dev->qdev.id = id;
 467     }
 468
 469     dev->irq = xics_alloc(spapr->icp, 0, dev->irq, false, &local_err);
 470     if (local_err) {
 471         error_propagate(errp, local_err);
 472         return;
 473     }
 474
 475     if (pc->rtce_window_size) {
 476         uint32_t liobn = SPAPR_VIO_LIOBN(dev->reg);
 477
 478         memory_region_init(&dev->mrroot, OBJECT(dev), "iommu-spapr-root",
 479                            ram_size);
 480         memory_region_init_alias(&dev->mrbypass, OBJECT(dev),
 481                                  "iommu-spapr-bypass", get_system_memory(),
 482                                  0, ram_size);
 483         memory_region_add_subregion_overlap(&dev->mrroot, 0, &dev->mrbypass, 1);
 484         address_space_init(&dev->as, &dev->mrroot, qdev->id);
 485
 486         dev->tcet = spapr_tce_new_table(qdev, liobn);
 487         spapr_tce_table_enable(dev->tcet, SPAPR_TCE_PAGE_SHIFT, 0,
 488                                pc->rtce_window_size >> SPAPR_TCE_PAGE_SHIFT);
 489         dev->tcet->vdev = dev;
 490         memory_region_add_subregion_overlap(&dev->mrroot, 0,
 491                                             spapr_tce_get_iommu(dev->tcet), 2);
 492     }
 493
 494     pc->realize(dev, errp);
 495 }
 496
 497 static target_ulong h_vio_signal(PowerPCCPU *cpu, sPAPRMachineState *spapr,
 498                                  target_ulong opcode,
 499                                  target_ulong *args)
 500 {
 501     target_ulong reg = args[0];
 502     target_ulong mode = args[1];
 503     VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
 504     VIOsPAPRDeviceClass *pc;
 505
 506     if (!dev) {
 507         return H_PARAMETER;
 508     }
 509
 510     pc = VIO_SPAPR_DEVICE_GET_CLASS(dev);
 511
 512     if (mode & ~pc->signal_mask) {
 513         return H_PARAMETER;
 514     }
 515
 516     dev->signal_state = mode;
 517
 518     return H_SUCCESS;
 519 }
 520
 521 VIOsPAPRBus *spapr_vio_bus_init(void)
 522 {
 523     VIOsPAPRBus *bus;
 524     BusState *qbus;
 525     DeviceState *dev;
 526
 527     /* Create bridge device */
 528     dev = qdev_create(NULL, TYPE_SPAPR_VIO_BRIDGE);
 529     qdev_init_nofail(dev);
 530
 531     /* Create bus on bridge device */
 532     qbus = qbus_create(TYPE_SPAPR_VIO_BUS, dev, "spapr-vio");
 533     bus = SPAPR_VIO_BUS(qbus);
 534     bus->next_reg = 0x71000000;
 535
 536     /* hcall-vio */
 537     spapr_register_hypercall(H_VIO_SIGNAL, h_vio_signal);
 538
 539     /* hcall-crq */
 540     spapr_register_hypercall(H_REG_CRQ, h_reg_crq);
 541     spapr_register_hypercall(H_FREE_CRQ, h_free_crq);
 542     spapr_register_hypercall(H_SEND_CRQ, h_send_crq);
 543     spapr_register_hypercall(H_ENABLE_CRQ, h_enable_crq);
 544
 545     /* RTAS calls */
 546     spapr_rtas_register(RTAS_IBM_SET_TCE_BYPASS, "ibm,set-tce-bypass",
 547                         rtas_set_tce_bypass);
 548     spapr_rtas_register(RTAS_QUIESCE, "quiesce", rtas_quiesce);
 549
 550     return bus;
 551 }
 552
 553 /* Represents sPAPR hcall VIO devices */
 554
 555 static int spapr_vio_bridge_init(SysBusDevice *dev)
 556 {
 557     /* nothing */
 558     return 0;
 559 }
 560
 561 static void spapr_vio_bridge_class_init(ObjectClass *klass, void *data)
 562 {
 563     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 564     DeviceClass *dc = DEVICE_CLASS(klass);
 565
 566     dc->fw_name = "vdevice";
 567     k->init = spapr_vio_bridge_init;
 568 }
 569
 570 static const TypeInfo spapr_vio_bridge_info = {
 571     .name          = TYPE_SPAPR_VIO_BRIDGE,
 572     .parent        = TYPE_SYS_BUS_DEVICE,
 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_UINT64(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 }