aboutsummaryrefslogtreecommitdiff
path: root/hw/spapr_vio.c
blob: 015941353e61fd1169ce3d1d0549c50fea7c27c8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
/*
 * QEMU sPAPR VIO code
 *
 * Copyright (c) 2010 David Gibson, IBM Corporation <dwg@au1.ibm.com>
 * Based on the s390 virtio bus code:
 * Copyright (c) 2009 Alexander Graf <agraf@suse.de>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

#include "hw.h"
#include "sysemu.h"
#include "boards.h"
#include "monitor.h"
#include "loader.h"
#include "elf.h"
#include "hw/sysbus.h"
#include "kvm.h"
#include "device_tree.h"
#include "kvm_ppc.h"

#include "hw/spapr.h"
#include "hw/spapr_vio.h"
#include "hw/xics.h"

#ifdef CONFIG_FDT
#include <libfdt.h>
#endif /* CONFIG_FDT */

/* #define DEBUG_SPAPR */
/* #define DEBUG_TCE */

#ifdef DEBUG_SPAPR
#define dprintf(fmt, ...) \
    do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
#else
#define dprintf(fmt, ...) \
    do { } while (0)
#endif

static struct BusInfo spapr_vio_bus_info = {
    .name       = "spapr-vio",
    .size       = sizeof(VIOsPAPRBus),
    .props = (Property[]) {
        DEFINE_PROP_UINT32("irq", VIOsPAPRDevice, vio_irq_num, 0), \
        DEFINE_PROP_END_OF_LIST(),
    },
};

VIOsPAPRDevice *spapr_vio_find_by_reg(VIOsPAPRBus *bus, uint32_t reg)
{
    DeviceState *qdev;
    VIOsPAPRDevice *dev = NULL;

    QTAILQ_FOREACH(qdev, &bus->bus.children, sibling) {
        dev = (VIOsPAPRDevice *)qdev;
        if (dev->reg == reg) {
            return dev;
        }
    }

    return NULL;
}

static char *vio_format_dev_name(VIOsPAPRDevice *dev)
{
    VIOsPAPRDeviceInfo *info = (VIOsPAPRDeviceInfo *)qdev_get_info(&dev->qdev);
    char *name;

    /* Device tree style name device@reg */
    if (asprintf(&name, "%s@%x", info->dt_name, dev->reg) < 0) {
        return NULL;
    }

    return name;
}

#ifdef CONFIG_FDT
static int vio_make_devnode(VIOsPAPRDevice *dev,
                            void *fdt)
{
    VIOsPAPRDeviceInfo *info = (VIOsPAPRDeviceInfo *)qdev_get_info(&dev->qdev);
    int vdevice_off, node_off, ret;
    char *dt_name;

    vdevice_off = fdt_path_offset(fdt, "/vdevice");
    if (vdevice_off < 0) {
        return vdevice_off;
    }

    dt_name = vio_format_dev_name(dev);
    if (!dt_name) {
        return -ENOMEM;
    }

    node_off = fdt_add_subnode(fdt, vdevice_off, dt_name);
    free(dt_name);
    if (node_off < 0) {
        return node_off;
    }

    ret = fdt_setprop_cell(fdt, node_off, "reg", dev->reg);
    if (ret < 0) {
        return ret;
    }

    if (info->dt_type) {
        ret = fdt_setprop_string(fdt, node_off, "device_type",
                                 info->dt_type);
        if (ret < 0) {
            return ret;
        }
    }

    if (info->dt_compatible) {
        ret = fdt_setprop_string(fdt, node_off, "compatible",
                                 info->dt_compatible);
        if (ret < 0) {
            return ret;
        }
    }

    if (dev->qirq) {
        uint32_t ints_prop[] = {cpu_to_be32(dev->vio_irq_num), 0};

        ret = fdt_setprop(fdt, node_off, "interrupts", ints_prop,
                          sizeof(ints_prop));
        if (ret < 0) {
            return ret;
        }
    }

    if (dev->rtce_window_size) {
        uint32_t dma_prop[] = {cpu_to_be32(dev->reg),
                               0, 0,
                               0, cpu_to_be32(dev->rtce_window_size)};

        ret = fdt_setprop_cell(fdt, node_off, "ibm,#dma-address-cells", 2);
        if (ret < 0) {
            return ret;
        }

        ret = fdt_setprop_cell(fdt, node_off, "ibm,#dma-size-cells", 2);
        if (ret < 0) {
            return ret;
        }

        ret = fdt_setprop(fdt, node_off, "ibm,my-dma-window", dma_prop,
                          sizeof(dma_prop));
        if (ret < 0) {
            return ret;
        }
    }

    if (info->devnode) {
        ret = (info->devnode)(dev, fdt, node_off);
        if (ret < 0) {
            return ret;
        }
    }

    return node_off;
}
#endif /* CONFIG_FDT */

/*
 * RTCE handling
 */

static void rtce_init(VIOsPAPRDevice *dev)
{
    size_t size = (dev->rtce_window_size >> SPAPR_VIO_TCE_PAGE_SHIFT)
        * sizeof(VIOsPAPR_RTCE);

    if (size) {
        dev->rtce_table = kvmppc_create_spapr_tce(dev->reg,
                                                  dev->rtce_window_size,
                                                  &dev->kvmtce_fd);

        if (!dev->rtce_table) {
            dev->rtce_table = g_malloc0(size);
        }
    }
}

static target_ulong h_put_tce(CPUState *env, sPAPREnvironment *spapr,
                              target_ulong opcode, target_ulong *args)
{
    target_ulong liobn = args[0];
    target_ulong ioba = args[1];
    target_ulong tce = args[2];
    VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, liobn);
    VIOsPAPR_RTCE *rtce;

    if (!dev) {
        hcall_dprintf("spapr_vio_put_tce on non-existent LIOBN "
                      TARGET_FMT_lx "\n", liobn);
        return H_PARAMETER;
    }

    ioba &= ~(SPAPR_VIO_TCE_PAGE_SIZE - 1);

#ifdef DEBUG_TCE
    fprintf(stderr, "spapr_vio_put_tce on %s  ioba 0x" TARGET_FMT_lx
            "  TCE 0x" TARGET_FMT_lx "\n", dev->qdev.id, ioba, tce);
#endif

    if (ioba >= dev->rtce_window_size) {
        hcall_dprintf("spapr_vio_put_tce on out-of-boards IOBA 0x"
                      TARGET_FMT_lx "\n", ioba);
        return H_PARAMETER;
    }

    rtce = dev->rtce_table + (ioba >> SPAPR_VIO_TCE_PAGE_SHIFT);
    rtce->tce = tce;

    return H_SUCCESS;
}

int spapr_vio_check_tces(VIOsPAPRDevice *dev, target_ulong ioba,
                         target_ulong len, enum VIOsPAPR_TCEAccess access)
{
    int start, end, i;

    start = ioba >> SPAPR_VIO_TCE_PAGE_SHIFT;
    end = (ioba + len - 1) >> SPAPR_VIO_TCE_PAGE_SHIFT;

    for (i = start; i <= end; i++) {
        if ((dev->rtce_table[i].tce & access) != access) {
#ifdef DEBUG_TCE
            fprintf(stderr, "FAIL on %d\n", i);
#endif
            return -1;
        }
    }

    return 0;
}

int spapr_tce_dma_write(VIOsPAPRDevice *dev, uint64_t taddr, const void *buf,
                        uint32_t size)
{
#ifdef DEBUG_TCE
    fprintf(stderr, "spapr_tce_dma_write taddr=0x%llx size=0x%x\n",
            (unsigned long long)taddr, size);
#endif

    /* Check for bypass */
    if (dev->flags & VIO_PAPR_FLAG_DMA_BYPASS) {
        cpu_physical_memory_write(taddr, buf, size);
        return 0;
    }

    while (size) {
        uint64_t tce;
        uint32_t lsize;
        uint64_t txaddr;

        /* Check if we are in bound */
        if (taddr >= dev->rtce_window_size) {
#ifdef DEBUG_TCE
            fprintf(stderr, "spapr_tce_dma_write out of bounds\n");
#endif
            return H_DEST_PARM;
        }
        tce = dev->rtce_table[taddr >> SPAPR_VIO_TCE_PAGE_SHIFT].tce;

        /* How much til end of page ? */
        lsize = MIN(size, ((~taddr) & SPAPR_VIO_TCE_PAGE_MASK) + 1);

        /* Check TCE */
        if (!(tce & 2)) {
            return H_DEST_PARM;
        }

        /* Translate */
        txaddr = (tce & ~SPAPR_VIO_TCE_PAGE_MASK) |
            (taddr & SPAPR_VIO_TCE_PAGE_MASK);

#ifdef DEBUG_TCE
        fprintf(stderr, " -> write to txaddr=0x%llx, size=0x%x\n",
                (unsigned long long)txaddr, lsize);
#endif

        /* Do it */
        cpu_physical_memory_write(txaddr, buf, lsize);
        buf += lsize;
        taddr += lsize;
        size -= lsize;
    }
    return 0;
}

int spapr_tce_dma_zero(VIOsPAPRDevice *dev, uint64_t taddr, uint32_t size)
{
    /* FIXME: allocating a temp buffer is nasty, but just stepping
     * through writing zeroes is awkward.  This will do for now. */
    uint8_t zeroes[size];

#ifdef DEBUG_TCE
    fprintf(stderr, "spapr_tce_dma_zero taddr=0x%llx size=0x%x\n",
            (unsigned long long)taddr, size);
#endif

    memset(zeroes, 0, size);
    return spapr_tce_dma_write(dev, taddr, zeroes, size);
}

void stb_tce(VIOsPAPRDevice *dev, uint64_t taddr, uint8_t val)
{
    spapr_tce_dma_write(dev, taddr, &val, sizeof(val));
}

void sth_tce(VIOsPAPRDevice *dev, uint64_t taddr, uint16_t val)
{
    val = tswap16(val);
    spapr_tce_dma_write(dev, taddr, &val, sizeof(val));
}


void stw_tce(VIOsPAPRDevice *dev, uint64_t taddr, uint32_t val)
{
    val = tswap32(val);
    spapr_tce_dma_write(dev, taddr, &val, sizeof(val));
}

void stq_tce(VIOsPAPRDevice *dev, uint64_t taddr, uint64_t val)
{
    val = tswap64(val);
    spapr_tce_dma_write(dev, taddr, &val, sizeof(val));
}

int spapr_tce_dma_read(VIOsPAPRDevice *dev, uint64_t taddr, void *buf,
                       uint32_t size)
{
#ifdef DEBUG_TCE
    fprintf(stderr, "spapr_tce_dma_write taddr=0x%llx size=0x%x\n",
            (unsigned long long)taddr, size);
#endif

    /* Check for bypass */
    if (dev->flags & VIO_PAPR_FLAG_DMA_BYPASS) {
        cpu_physical_memory_read(taddr, buf, size);
        return 0;
    }

    while (size) {
        uint64_t tce;
        uint32_t lsize;
        uint64_t txaddr;

        /* Check if we are in bound */
        if (taddr >= dev->rtce_window_size) {
#ifdef DEBUG_TCE
            fprintf(stderr, "spapr_tce_dma_read out of bounds\n");
#endif
            return H_DEST_PARM;
        }
        tce = dev->rtce_table[taddr >> SPAPR_VIO_TCE_PAGE_SHIFT].tce;

        /* How much til end of page ? */
        lsize = MIN(size, ((~taddr) & SPAPR_VIO_TCE_PAGE_MASK) + 1);

        /* Check TCE */
        if (!(tce & 1)) {
            return H_DEST_PARM;
        }

        /* Translate */
        txaddr = (tce & ~SPAPR_VIO_TCE_PAGE_MASK) |
            (taddr & SPAPR_VIO_TCE_PAGE_MASK);

#ifdef DEBUG_TCE
        fprintf(stderr, " -> write to txaddr=0x%llx, size=0x%x\n",
                (unsigned long long)txaddr, lsize);
#endif
        /* Do it */
        cpu_physical_memory_read(txaddr, buf, lsize);
        buf += lsize;
        taddr += lsize;
        size -= lsize;
    }
    return H_SUCCESS;
}

uint64_t ldq_tce(VIOsPAPRDevice *dev, uint64_t taddr)
{
    uint64_t val;

    spapr_tce_dma_read(dev, taddr, &val, sizeof(val));
    return tswap64(val);
}

/*
 * CRQ handling
 */
static target_ulong h_reg_crq(CPUState *env, sPAPREnvironment *spapr,
                              target_ulong opcode, target_ulong *args)
{
    target_ulong reg = args[0];
    target_ulong queue_addr = args[1];
    target_ulong queue_len = args[2];
    VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);

    if (!dev) {
        hcall_dprintf("h_reg_crq on non-existent unit 0x"
                      TARGET_FMT_lx "\n", reg);
        return H_PARAMETER;
    }

    /* We can't grok a queue size bigger than 256M for now */
    if (queue_len < 0x1000 || queue_len > 0x10000000) {
        hcall_dprintf("h_reg_crq, queue size too small or too big (0x%llx)\n",
                      (unsigned long long)queue_len);
        return H_PARAMETER;
    }

    /* Check queue alignment */
    if (queue_addr & 0xfff) {
        hcall_dprintf("h_reg_crq, queue not aligned (0x%llx)\n",
                      (unsigned long long)queue_addr);
        return H_PARAMETER;
    }

    /* Check if device supports CRQs */
    if (!dev->crq.SendFunc) {
        return H_NOT_FOUND;
    }


    /* Already a queue ? */
    if (dev->crq.qsize) {
        return H_RESOURCE;
    }
    dev->crq.qladdr = queue_addr;
    dev->crq.qsize = queue_len;
    dev->crq.qnext = 0;

    dprintf("CRQ for dev 0x" TARGET_FMT_lx " registered at 0x"
            TARGET_FMT_lx "/0x" TARGET_FMT_lx "\n",
            reg, queue_addr, queue_len);
    return H_SUCCESS;
}

static target_ulong h_free_crq(CPUState *env, sPAPREnvironment *spapr,
                               target_ulong opcode, target_ulong *args)
{
    target_ulong reg = args[0];
    VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);

    if (!dev) {
        hcall_dprintf("h_free_crq on non-existent unit 0x"
                      TARGET_FMT_lx "\n", reg);
        return H_PARAMETER;
    }

    dev->crq.qladdr = 0;
    dev->crq.qsize = 0;
    dev->crq.qnext = 0;

    dprintf("CRQ for dev 0x" TARGET_FMT_lx " freed\n", reg);

    return H_SUCCESS;
}

static target_ulong h_send_crq(CPUState *env, sPAPREnvironment *spapr,
                               target_ulong opcode, target_ulong *args)
{
    target_ulong reg = args[0];
    target_ulong msg_hi = args[1];
    target_ulong msg_lo = args[2];
    VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
    uint64_t crq_mangle[2];

    if (!dev) {
        hcall_dprintf("h_send_crq on non-existent unit 0x"
                      TARGET_FMT_lx "\n", reg);
        return H_PARAMETER;
    }
    crq_mangle[0] = cpu_to_be64(msg_hi);
    crq_mangle[1] = cpu_to_be64(msg_lo);

    if (dev->crq.SendFunc) {
        return dev->crq.SendFunc(dev, (uint8_t *)crq_mangle);
    }

    return H_HARDWARE;
}

static target_ulong h_enable_crq(CPUState *env, sPAPREnvironment *spapr,
                                 target_ulong opcode, target_ulong *args)
{
    target_ulong reg = args[0];
    VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);

    if (!dev) {
        hcall_dprintf("h_enable_crq on non-existent unit 0x"
                      TARGET_FMT_lx "\n", reg);
        return H_PARAMETER;
    }

    return 0;
}

/* Returns negative error, 0 success, or positive: queue full */
int spapr_vio_send_crq(VIOsPAPRDevice *dev, uint8_t *crq)
{
    int rc;
    uint8_t byte;

    if (!dev->crq.qsize) {
        fprintf(stderr, "spapr_vio_send_creq on uninitialized queue\n");
        return -1;
    }

    /* Maybe do a fast path for KVM just writing to the pages */
    rc = spapr_tce_dma_read(dev, dev->crq.qladdr + dev->crq.qnext, &byte, 1);
    if (rc) {
        return rc;
    }
    if (byte != 0) {
        return 1;
    }

    rc = spapr_tce_dma_write(dev, dev->crq.qladdr + dev->crq.qnext + 8,
                             &crq[8], 8);
    if (rc) {
        return rc;
    }

    kvmppc_eieio();

    rc = spapr_tce_dma_write(dev, dev->crq.qladdr + dev->crq.qnext, crq, 8);
    if (rc) {
        return rc;
    }

    dev->crq.qnext = (dev->crq.qnext + 16) % dev->crq.qsize;

    if (dev->signal_state & 1) {
        qemu_irq_pulse(dev->qirq);
    }

    return 0;
}

/* "quiesce" handling */

static void spapr_vio_quiesce_one(VIOsPAPRDevice *dev)
{
    dev->flags &= ~VIO_PAPR_FLAG_DMA_BYPASS;

    if (dev->rtce_table) {
        size_t size = (dev->rtce_window_size >> SPAPR_VIO_TCE_PAGE_SHIFT)
            * sizeof(VIOsPAPR_RTCE);
        memset(dev->rtce_table, 0, size);
    }

    dev->crq.qladdr = 0;
    dev->crq.qsize = 0;
    dev->crq.qnext = 0;
}

static void rtas_set_tce_bypass(sPAPREnvironment *spapr, uint32_t token,
                                uint32_t nargs, target_ulong args,
                                uint32_t nret, target_ulong rets)
{
    VIOsPAPRBus *bus = spapr->vio_bus;
    VIOsPAPRDevice *dev;
    uint32_t unit, enable;

    if (nargs != 2) {
        rtas_st(rets, 0, -3);
        return;
    }
    unit = rtas_ld(args, 0);
    enable = rtas_ld(args, 1);
    dev = spapr_vio_find_by_reg(bus, unit);
    if (!dev) {
        rtas_st(rets, 0, -3);
        return;
    }
    if (enable) {
        dev->flags |= VIO_PAPR_FLAG_DMA_BYPASS;
    } else {
        dev->flags &= ~VIO_PAPR_FLAG_DMA_BYPASS;
    }

    rtas_st(rets, 0, 0);
}

static void rtas_quiesce(sPAPREnvironment *spapr, uint32_t token,
                         uint32_t nargs, target_ulong args,
                         uint32_t nret, target_ulong rets)
{
    VIOsPAPRBus *bus = spapr->vio_bus;
    DeviceState *qdev;
    VIOsPAPRDevice *dev = NULL;

    if (nargs != 0) {
        rtas_st(rets, 0, -3);
        return;
    }

    QTAILQ_FOREACH(qdev, &bus->bus.children, sibling) {
        dev = (VIOsPAPRDevice *)qdev;
        spapr_vio_quiesce_one(dev);
    }

    rtas_st(rets, 0, 0);
}

static int spapr_vio_check_reg(VIOsPAPRDevice *sdev, VIOsPAPRDeviceInfo *info)
{
    VIOsPAPRDevice *other_sdev;
    DeviceState *qdev;
    VIOsPAPRBus *sbus;

    sbus = DO_UPCAST(VIOsPAPRBus, bus, sdev->qdev.parent_bus);

    /*
     * Check two device aren't given clashing addresses by the user (or some
     * other mechanism). We have to open code this because we have to check
     * for matches with devices other than us.
     */
    QTAILQ_FOREACH(qdev, &sbus->bus.children, sibling) {
        other_sdev = DO_UPCAST(VIOsPAPRDevice, qdev, qdev);

        if (other_sdev != sdev && other_sdev->reg == sdev->reg) {
            fprintf(stderr, "vio: %s and %s devices conflict at address %#x\n",
                    info->qdev.name, other_sdev->qdev.info->name, sdev->reg);
            return -EEXIST;
        }
    }

    return 0;
}

static int spapr_vio_busdev_init(DeviceState *qdev, DeviceInfo *qinfo)
{
    VIOsPAPRDeviceInfo *info = (VIOsPAPRDeviceInfo *)qinfo;
    VIOsPAPRDevice *dev = (VIOsPAPRDevice *)qdev;
    char *id;
    int ret;

    ret = spapr_vio_check_reg(dev, info);
    if (ret) {
        return ret;
    }

    /* Don't overwrite ids assigned on the command line */
    if (!dev->qdev.id) {
        id = vio_format_dev_name(dev);
        if (!id) {
            return -1;
        }
        dev->qdev.id = id;
    }

    dev->qirq = spapr_allocate_irq(dev->vio_irq_num, &dev->vio_irq_num);
    if (!dev->qirq) {
        return -1;
    }

    rtce_init(dev);

    return info->init(dev);
}

void spapr_vio_bus_register_withprop(VIOsPAPRDeviceInfo *info)
{
    info->qdev.init = spapr_vio_busdev_init;
    info->qdev.bus_info = &spapr_vio_bus_info;

    assert(info->qdev.size >= sizeof(VIOsPAPRDevice));
    qdev_register(&info->qdev);
}

static target_ulong h_vio_signal(CPUState *env, sPAPREnvironment *spapr,
                                 target_ulong opcode,
                                 target_ulong *args)
{
    target_ulong reg = args[0];
    target_ulong mode = args[1];
    VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
    VIOsPAPRDeviceInfo *info;

    if (!dev) {
        return H_PARAMETER;
    }

    info = (VIOsPAPRDeviceInfo *)qdev_get_info(&dev->qdev);

    if (mode & ~info->signal_mask) {
        return H_PARAMETER;
    }

    dev->signal_state = mode;

    return H_SUCCESS;
}

VIOsPAPRBus *spapr_vio_bus_init(void)
{
    VIOsPAPRBus *bus;
    BusState *qbus;
    DeviceState *dev;

    /* Create bridge device */
    dev = qdev_create(NULL, "spapr-vio-bridge");
    qdev_init_nofail(dev);

    /* Create bus on bridge device */

    qbus = qbus_create(&spapr_vio_bus_info, dev, "spapr-vio");
    bus = DO_UPCAST(VIOsPAPRBus, bus, qbus);

    /* hcall-vio */
    spapr_register_hypercall(H_VIO_SIGNAL, h_vio_signal);

    /* hcall-tce */
    spapr_register_hypercall(H_PUT_TCE, h_put_tce);

    /* hcall-crq */
    spapr_register_hypercall(H_REG_CRQ, h_reg_crq);
    spapr_register_hypercall(H_FREE_CRQ, h_free_crq);
    spapr_register_hypercall(H_SEND_CRQ, h_send_crq);
    spapr_register_hypercall(H_ENABLE_CRQ, h_enable_crq);

    /* RTAS calls */
    spapr_rtas_register("ibm,set-tce-bypass", rtas_set_tce_bypass);
    spapr_rtas_register("quiesce", rtas_quiesce);

    return bus;
}

/* Represents sPAPR hcall VIO devices */

static int spapr_vio_bridge_init(SysBusDevice *dev)
{
    /* nothing */
    return 0;
}

static SysBusDeviceInfo spapr_vio_bridge_info = {
    .init = spapr_vio_bridge_init,
    .qdev.name  = "spapr-vio-bridge",
    .qdev.size  = sizeof(SysBusDevice),
    .qdev.no_user = 1,
};

static void spapr_vio_register_devices(void)
{
    sysbus_register_withprop(&spapr_vio_bridge_info);
}

device_init(spapr_vio_register_devices)

#ifdef CONFIG_FDT
static int compare_reg(const void *p1, const void *p2)
{
    VIOsPAPRDevice const *dev1, *dev2;

    dev1 = (VIOsPAPRDevice *)*(DeviceState **)p1;
    dev2 = (VIOsPAPRDevice *)*(DeviceState **)p2;

    if (dev1->reg < dev2->reg) {
        return -1;
    }
    if (dev1->reg == dev2->reg) {
        return 0;
    }

    /* dev1->reg > dev2->reg */
    return 1;
}

int spapr_populate_vdevice(VIOsPAPRBus *bus, void *fdt)
{
    DeviceState *qdev, **qdevs;
    int i, num, ret = 0;

    /* Count qdevs on the bus list */
    num = 0;
    QTAILQ_FOREACH(qdev, &bus->bus.children, sibling) {
        num++;
    }

    /* Copy out into an array of pointers */
    qdevs = g_malloc(sizeof(qdev) * num);
    num = 0;
    QTAILQ_FOREACH(qdev, &bus->bus.children, sibling) {
        qdevs[num++] = qdev;
    }

    /* Sort the array */
    qsort(qdevs, num, sizeof(qdev), compare_reg);

    /* Hack alert. Give the devices to libfdt in reverse order, we happen
     * to know that will mean they are in forward order in the tree. */
    for (i = num - 1; i >= 0; i--) {
        VIOsPAPRDevice *dev = (VIOsPAPRDevice *)(qdevs[i]);

        ret = vio_make_devnode(dev, fdt);

        if (ret < 0) {
            goto out;
        }
    }

    ret = 0;
out:
    free(qdevs);

    return ret;
}

int spapr_populate_chosen_stdout(void *fdt, VIOsPAPRBus *bus)
{
    VIOsPAPRDevice *dev;
    char *name, *path;
    int ret, offset;

    dev = spapr_vty_get_default(bus);
    if (!dev)
        return 0;

    offset = fdt_path_offset(fdt, "/chosen");
    if (offset < 0) {
        return offset;
    }

    name = vio_format_dev_name(dev);
    if (!name) {
        return -ENOMEM;
    }

    if (asprintf(&path, "/vdevice/%s", name) < 0) {
        path = NULL;
        ret = -ENOMEM;
        goto out;
    }

    ret = fdt_setprop_string(fdt, offset, "linux,stdout-path", path);
out:
    free(name);
    free(path);

    return ret;
}
#endif /* CONFIG_FDT */