aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc/kernel/irq.c
blob: 77be3d058a658fa447a2235a8441d320be245d20 (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
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
/*
 *  Derived from arch/i386/kernel/irq.c
 *    Copyright (C) 1992 Linus Torvalds
 *  Adapted from arch/i386 by Gary Thomas
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *  Updated and modified by Cort Dougan <cort@fsmlabs.com>
 *    Copyright (C) 1996-2001 Cort Dougan
 *  Adapted for Power Macintosh by Paul Mackerras
 *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * This file contains the code used by various IRQ handling routines:
 * asking for different IRQ's should be done through these routines
 * instead of just grabbing them. Thus setups with different IRQ numbers
 * shouldn't result in any weird surprises, and installing new handlers
 * should be easier.
 *
 * The MPC8xx has an interrupt mask in the SIU.  If a bit is set, the
 * interrupt is _enabled_.  As expected, IRQ0 is bit 0 in the 32-bit
 * mask register (of which only 16 are defined), hence the weird shifting
 * and complement of the cached_irq_mask.  I want to be able to stuff
 * this right into the SIU SMASK register.
 * Many of the prep/chrp functions are conditional compiled on CONFIG_8xx
 * to reduce code space and undefined function references.
 */

#undef DEBUG

#include <linux/module.h>
#include <linux/threads.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/seq_file.h>
#include <linux/cpumask.h>
#include <linux/profile.h>
#include <linux/bitops.h>
#include <linux/list.h>
#include <linux/radix-tree.h>
#include <linux/mutex.h>
#include <linux/bootmem.h>
#include <linux/pci.h>
#include <linux/debugfs.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/irq.h>
#include <asm/cache.h>
#include <asm/prom.h>
#include <asm/ptrace.h>
#include <asm/machdep.h>
#include <asm/udbg.h>
#ifdef CONFIG_PPC64
#include <asm/paca.h>
#include <asm/firmware.h>
#include <asm/lv1call.h>
#endif
#define CREATE_TRACE_POINTS
#include <asm/trace.h>

DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
EXPORT_PER_CPU_SYMBOL(irq_stat);

int __irq_offset_value;

#ifdef CONFIG_PPC32
EXPORT_SYMBOL(__irq_offset_value);
atomic_t ppc_n_lost_interrupts;

#ifdef CONFIG_TAU_INT
extern int tau_initialized;
extern int tau_interrupts(int);
#endif
#endif /* CONFIG_PPC32 */

#ifdef CONFIG_PPC64

#ifndef CONFIG_SPARSE_IRQ
EXPORT_SYMBOL(irq_desc);
#endif

int distribute_irqs = 1;

static inline notrace unsigned long get_hard_enabled(void)
{
	unsigned long enabled;

	__asm__ __volatile__("lbz %0,%1(13)"
	: "=r" (enabled) : "i" (offsetof(struct paca_struct, hard_enabled)));

	return enabled;
}

static inline notrace void set_soft_enabled(unsigned long enable)
{
	__asm__ __volatile__("stb %0,%1(13)"
	: : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
}

notrace void raw_local_irq_restore(unsigned long en)
{
	/*
	 * get_paca()->soft_enabled = en;
	 * Is it ever valid to use local_irq_restore(0) when soft_enabled is 1?
	 * That was allowed before, and in such a case we do need to take care
	 * that gcc will set soft_enabled directly via r13, not choose to use
	 * an intermediate register, lest we're preempted to a different cpu.
	 */
	set_soft_enabled(en);
	if (!en)
		return;

#ifdef CONFIG_PPC_STD_MMU_64
	if (firmware_has_feature(FW_FEATURE_ISERIES)) {
		/*
		 * Do we need to disable preemption here?  Not really: in the
		 * unlikely event that we're preempted to a different cpu in
		 * between getting r13, loading its lppaca_ptr, and loading
		 * its any_int, we might call iseries_handle_interrupts without
		 * an interrupt pending on the new cpu, but that's no disaster,
		 * is it?  And the business of preempting us off the old cpu
		 * would itself involve a local_irq_restore which handles the
		 * interrupt to that cpu.
		 *
		 * But use "local_paca->lppaca_ptr" instead of "get_lppaca()"
		 * to avoid any preemption checking added into get_paca().
		 */
		if (local_paca->lppaca_ptr->int_dword.any_int)
			iseries_handle_interrupts();
	}
#endif /* CONFIG_PPC_STD_MMU_64 */

	/*
	 * if (get_paca()->hard_enabled) return;
	 * But again we need to take care that gcc gets hard_enabled directly
	 * via r13, not choose to use an intermediate register, lest we're
	 * preempted to a different cpu in between the two instructions.
	 */
	if (get_hard_enabled())
		return;

	/*
	 * Need to hard-enable interrupts here.  Since currently disabled,
	 * no need to take further asm precautions against preemption; but
	 * use local_paca instead of get_paca() to avoid preemption checking.
	 */
	local_paca->hard_enabled = en;
	if ((int)mfspr(SPRN_DEC) < 0)
		mtspr(SPRN_DEC, 1);

	/*
	 * Force the delivery of pending soft-disabled interrupts on PS3.
	 * Any HV call will have this side effect.
	 */
	if (firmware_has_feature(FW_FEATURE_PS3_LV1)) {
		u64 tmp;
		lv1_get_version_info(&tmp);
	}

	__hard_irq_enable();
}
EXPORT_SYMBOL(raw_local_irq_restore);
#endif /* CONFIG_PPC64 */

static int show_other_interrupts(struct seq_file *p, int prec)
{
	int j;

#if defined(CONFIG_PPC32) && defined(CONFIG_TAU_INT)
	if (tau_initialized) {
		seq_printf(p, "%*s: ", prec, "TAU");
		for_each_online_cpu(j)
			seq_printf(p, "%10u ", tau_interrupts(j));
		seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
	}
#endif /* CONFIG_PPC32 && CONFIG_TAU_INT */

	seq_printf(p, "%*s: ", prec, "LOC");
	for_each_online_cpu(j)
		seq_printf(p, "%10u ", per_cpu(irq_stat, j).timer_irqs);
        seq_printf(p, "  Local timer interrupts\n");

	seq_printf(p, "%*s: ", prec, "SPU");
	for_each_online_cpu(j)
		seq_printf(p, "%10u ", per_cpu(irq_stat, j).spurious_irqs);
	seq_printf(p, "  Spurious interrupts\n");

	seq_printf(p, "%*s: ", prec, "CNT");
	for_each_online_cpu(j)
		seq_printf(p, "%10u ", per_cpu(irq_stat, j).pmu_irqs);
	seq_printf(p, "  Performance monitoring interrupts\n");

	seq_printf(p, "%*s: ", prec, "MCE");
	for_each_online_cpu(j)
		seq_printf(p, "%10u ", per_cpu(irq_stat, j).mce_exceptions);
	seq_printf(p, "  Machine check exceptions\n");

	return 0;
}

int show_interrupts(struct seq_file *p, void *v)
{
	unsigned long flags, any_count = 0;
	int i = *(loff_t *) v, j, prec;
	struct irqaction *action;
	struct irq_desc *desc;

	if (i > nr_irqs)
		return 0;

	for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
		j *= 10;

	if (i == nr_irqs)
		return show_other_interrupts(p, prec);

	/* print header */
	if (i == 0) {
		seq_printf(p, "%*s", prec + 8, "");
		for_each_online_cpu(j)
			seq_printf(p, "CPU%-8d", j);
		seq_putc(p, '\n');
	}

	desc = irq_to_desc(i);
	if (!desc)
		return 0;

	raw_spin_lock_irqsave(&desc->lock, flags);
	for_each_online_cpu(j)
		any_count |= kstat_irqs_cpu(i, j);
	action = desc->action;
	if (!action && !any_count)
		goto out;

	seq_printf(p, "%*d: ", prec, i);
	for_each_online_cpu(j)
		seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));

	if (desc->chip)
		seq_printf(p, "  %-16s", desc->chip->name);
	else
		seq_printf(p, "  %-16s", "None");
	seq_printf(p, " %-8s", (desc->status & IRQ_LEVEL) ? "Level" : "Edge");

	if (action) {
		seq_printf(p, "     %s", action->name);
		while ((action = action->next) != NULL)
			seq_printf(p, ", %s", action->name);
	}

	seq_putc(p, '\n');
out:
	raw_spin_unlock_irqrestore(&desc->lock, flags);
	return 0;
}

/*
 * /proc/stat helpers
 */
u64 arch_irq_stat_cpu(unsigned int cpu)
{
	u64 sum = per_cpu(irq_stat, cpu).timer_irqs;

	sum += per_cpu(irq_stat, cpu).pmu_irqs;
	sum += per_cpu(irq_stat, cpu).mce_exceptions;
	sum += per_cpu(irq_stat, cpu).spurious_irqs;

	return sum;
}

#ifdef CONFIG_HOTPLUG_CPU
void fixup_irqs(const struct cpumask *map)
{
	struct irq_desc *desc;
	unsigned int irq;
	static int warned;
	cpumask_var_t mask;

	alloc_cpumask_var(&mask, GFP_KERNEL);

	for_each_irq(irq) {
		desc = irq_to_desc(irq);
		if (!desc)
			continue;

		if (desc->status & IRQ_PER_CPU)
			continue;

		cpumask_and(mask, desc->affinity, map);
		if (cpumask_any(mask) >= nr_cpu_ids) {
			printk("Breaking affinity for irq %i\n", irq);
			cpumask_copy(mask, map);
		}
		if (desc->chip->set_affinity)
			desc->chip->set_affinity(irq, mask);
		else if (desc->action && !(warned++))
			printk("Cannot set affinity for irq %i\n", irq);
	}

	free_cpumask_var(mask);

	local_irq_enable();
	mdelay(1);
	local_irq_disable();
}
#endif

static inline void handle_one_irq(unsigned int irq)
{
	struct thread_info *curtp, *irqtp;
	unsigned long saved_sp_limit;
	struct irq_desc *desc;

	/* Switch to the irq stack to handle this */
	curtp = current_thread_info();
	irqtp = hardirq_ctx[smp_processor_id()];

	if (curtp == irqtp) {
		/* We're already on the irq stack, just handle it */
		generic_handle_irq(irq);
		return;
	}

	desc = irq_to_desc(irq);
	saved_sp_limit = current->thread.ksp_limit;

	irqtp->task = curtp->task;
	irqtp->flags = 0;

	/* Copy the softirq bits in preempt_count so that the
	 * softirq checks work in the hardirq context. */
	irqtp->preempt_count = (irqtp->preempt_count & ~SOFTIRQ_MASK) |
			       (curtp->preempt_count & SOFTIRQ_MASK);

	current->thread.ksp_limit = (unsigned long)irqtp +
		_ALIGN_UP(sizeof(struct thread_info), 16);

	call_handle_irq(irq, desc, irqtp, desc->handle_irq);
	current->thread.ksp_limit = saved_sp_limit;
	irqtp->task = NULL;

	/* Set any flag that may have been set on the
	 * alternate stack
	 */
	if (irqtp->flags)
		set_bits(irqtp->flags, &curtp->flags);
}

static inline void check_stack_overflow(void)
{
#ifdef CONFIG_DEBUG_STACKOVERFLOW
	long sp;

	sp = __get_SP() & (THREAD_SIZE-1);

	/* check for stack overflow: is there less than 2KB free? */
	if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
		printk("do_IRQ: stack overflow: %ld\n",
			sp - sizeof(struct thread_info));
		dump_stack();
	}
#endif
}

void do_IRQ(struct pt_regs *regs)
{
	struct pt_regs *old_regs = set_irq_regs(regs);
	unsigned int irq;

	trace_irq_entry(regs);

	irq_enter();

	check_stack_overflow();

	irq = ppc_md.get_irq();

	if (irq != NO_IRQ && irq != NO_IRQ_IGNORE)
		handle_one_irq(irq);
	else if (irq != NO_IRQ_IGNORE)
		__get_cpu_var(irq_stat).spurious_irqs++;

	irq_exit();
	set_irq_regs(old_regs);

#ifdef CONFIG_PPC_ISERIES
	if (firmware_has_feature(FW_FEATURE_ISERIES) &&
			get_lppaca()->int_dword.fields.decr_int) {
		get_lppaca()->int_dword.fields.decr_int = 0;
		/* Signal a fake decrementer interrupt */
		timer_interrupt(regs);
	}
#endif

	trace_irq_exit(regs);
}

void __init init_IRQ(void)
{
	if (ppc_md.init_IRQ)
		ppc_md.init_IRQ();

	exc_lvl_ctx_init();

	irq_ctx_init();
}

#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
struct thread_info   *critirq_ctx[NR_CPUS] __read_mostly;
struct thread_info    *dbgirq_ctx[NR_CPUS] __read_mostly;
struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly;

void exc_lvl_ctx_init(void)
{
	struct thread_info *tp;
	int i;

	for_each_possible_cpu(i) {
		memset((void *)critirq_ctx[i], 0, THREAD_SIZE);
		tp = critirq_ctx[i];
		tp->cpu = i;
		tp->preempt_count = 0;

#ifdef CONFIG_BOOKE
		memset((void *)dbgirq_ctx[i], 0, THREAD_SIZE);
		tp = dbgirq_ctx[i];
		tp->cpu = i;
		tp->preempt_count = 0;

		memset((void *)mcheckirq_ctx[i], 0, THREAD_SIZE);
		tp = mcheckirq_ctx[i];
		tp->cpu = i;
		tp->preempt_count = HARDIRQ_OFFSET;
#endif
	}
}
#endif

struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;
struct thread_info *hardirq_ctx[NR_CPUS] __read_mostly;

void irq_ctx_init(void)
{
	struct thread_info *tp;
	int i;

	for_each_possible_cpu(i) {
		memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
		tp = softirq_ctx[i];
		tp->cpu = i;
		tp->preempt_count = 0;

		memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
		tp = hardirq_ctx[i];
		tp->cpu = i;
		tp->preempt_count = HARDIRQ_OFFSET;
	}
}

static inline void do_softirq_onstack(void)
{
	struct thread_info *curtp, *irqtp;
	unsigned long saved_sp_limit = current->thread.ksp_limit;

	curtp = current_thread_info();
	irqtp = softirq_ctx[smp_processor_id()];
	irqtp->task = curtp->task;
	current->thread.ksp_limit = (unsigned long)irqtp +
				    _ALIGN_UP(sizeof(struct thread_info), 16);
	call_do_softirq(irqtp);
	current->thread.ksp_limit = saved_sp_limit;
	irqtp->task = NULL;
}

void do_softirq(void)
{
	unsigned long flags;

	if (in_interrupt())
		return;

	local_irq_save(flags);

	if (local_softirq_pending())
		do_softirq_onstack();

	local_irq_restore(flags);
}


/*
 * IRQ controller and virtual interrupts
 */

static LIST_HEAD(irq_hosts);
static DEFINE_RAW_SPINLOCK(irq_big_lock);
static unsigned int revmap_trees_allocated;
static DEFINE_MUTEX(revmap_trees_mutex);
struct irq_map_entry irq_map[NR_IRQS];
static unsigned int irq_virq_count = NR_IRQS;
static struct irq_host *irq_default_host;

irq_hw_number_t virq_to_hw(unsigned int virq)
{
	return irq_map[virq].hwirq;
}
EXPORT_SYMBOL_GPL(virq_to_hw);

static int default_irq_host_match(struct irq_host *h, struct device_node *np)
{
	return h->of_node != NULL && h->of_node == np;
}

struct irq_host *irq_alloc_host(struct device_node *of_node,
				unsigned int revmap_type,
				unsigned int revmap_arg,
				struct irq_host_ops *ops,
				irq_hw_number_t inval_irq)
{
	struct irq_host *host;
	unsigned int size = sizeof(struct irq_host);
	unsigned int i;
	unsigned int *rmap;
	unsigned long flags;

	/* Allocate structure and revmap table if using linear mapping */
	if (revmap_type == IRQ_HOST_MAP_LINEAR)
		size += revmap_arg * sizeof(unsigned int);
	host = zalloc_maybe_bootmem(size, GFP_KERNEL);
	if (host == NULL)
		return NULL;

	/* Fill structure */
	host->revmap_type = revmap_type;
	host->inval_irq = inval_irq;
	host->ops = ops;
	host->of_node = of_node_get(of_node);

	if (host->ops->match == NULL)
		host->ops->match = default_irq_host_match;

	raw_spin_lock_irqsave(&irq_big_lock, flags);

	/* If it's a legacy controller, check for duplicates and
	 * mark it as allocated (we use irq 0 host pointer for that
	 */
	if (revmap_type == IRQ_HOST_MAP_LEGACY) {
		if (irq_map[0].host != NULL) {
			raw_spin_unlock_irqrestore(&irq_big_lock, flags);
			/* If we are early boot, we can't free the structure,
			 * too bad...
			 * this will be fixed once slab is made available early
			 * instead of the current cruft
			 */
			if (mem_init_done)
				kfree(host);
			return NULL;
		}
		irq_map[0].host = host;
	}

	list_add(&host->link, &irq_hosts);
	raw_spin_unlock_irqrestore(&irq_big_lock, flags);

	/* Additional setups per revmap type */
	switch(revmap_type) {
	case IRQ_HOST_MAP_LEGACY:
		/* 0 is always the invalid number for legacy */
		host->inval_irq = 0;
		/* setup us as the host for all legacy interrupts */
		for (i = 1; i < NUM_ISA_INTERRUPTS; i++) {
			irq_map[i].hwirq = i;
			smp_wmb();
			irq_map[i].host = host;
			smp_wmb();

			/* Clear norequest flags */
			irq_to_desc(i)->status &= ~IRQ_NOREQUEST;

			/* Legacy flags are left to default at this point,
			 * one can then use irq_create_mapping() to
			 * explicitly change them
			 */
			ops->map(host, i, i);
		}
		break;
	case IRQ_HOST_MAP_LINEAR:
		rmap = (unsigned int *)(host + 1);
		for (i = 0; i < revmap_arg; i++)
			rmap[i] = NO_IRQ;
		host->revmap_data.linear.size = revmap_arg;
		smp_wmb();
		host->revmap_data.linear.revmap = rmap;
		break;
	default:
		break;
	}

	pr_debug("irq: Allocated host of type %d @0x%p\n", revmap_type, host);

	return host;
}

struct irq_host *irq_find_host(struct device_node *node)
{
	struct irq_host *h, *found = NULL;
	unsigned long flags;

	/* We might want to match the legacy controller last since
	 * it might potentially be set to match all interrupts in
	 * the absence of a device node. This isn't a problem so far
	 * yet though...
	 */
	raw_spin_lock_irqsave(&irq_big_lock, flags);
	list_for_each_entry(h, &irq_hosts, link)
		if (h->ops->match(h, node)) {
			found = h;
			break;
		}
	raw_spin_unlock_irqrestore(&irq_big_lock, flags);
	return found;
}
EXPORT_SYMBOL_GPL(irq_find_host);

void irq_set_default_host(struct irq_host *host)
{
	pr_debug("irq: Default host set to @0x%p\n", host);

	irq_default_host = host;
}

void irq_set_virq_count(unsigned int count)
{
	pr_debug("irq: Trying to set virq count to %d\n", count);

	BUG_ON(count < NUM_ISA_INTERRUPTS);
	if (count < NR_IRQS)
		irq_virq_count = count;
}

static int irq_setup_virq(struct irq_host *host, unsigned int virq,
			    irq_hw_number_t hwirq)
{
	struct irq_desc *desc;

	desc = irq_to_desc_alloc_node(virq, 0);
	if (!desc) {
		pr_debug("irq: -> allocating desc failed\n");
		goto error;
	}

	/* Clear IRQ_NOREQUEST flag */
	desc->status &= ~IRQ_NOREQUEST;

	/* map it */
	smp_wmb();
	irq_map[virq].hwirq = hwirq;
	smp_mb();

	if (host->ops->map(host, virq, hwirq)) {
		pr_debug("irq: -> mapping failed, freeing\n");
		goto error;
	}

	return 0;

error:
	irq_free_virt(virq, 1);
	return -1;
}

unsigned int irq_create_direct_mapping(struct irq_host *host)
{
	unsigned int virq;

	if (host == NULL)
		host = irq_default_host;

	BUG_ON(host == NULL);
	WARN_ON(host->revmap_type != IRQ_HOST_MAP_NOMAP);

	virq = irq_alloc_virt(host, 1, 0);
	if (virq == NO_IRQ) {
		pr_debug("irq: create_direct virq allocation failed\n");
		return NO_IRQ;
	}

	pr_debug("irq: create_direct obtained virq %d\n", virq);

	if (irq_setup_virq(host, virq, virq))
		return NO_IRQ;

	return virq;
}

unsigned int irq_create_mapping(struct irq_host *host,
				irq_hw_number_t hwirq)
{
	unsigned int virq, hint;

	pr_debug("irq: irq_create_mapping(0x%p, 0x%lx)\n", host, hwirq);

	/* Look for default host if nececssary */
	if (host == NULL)
		host = irq_default_host;
	if (host == NULL) {
		printk(KERN_WARNING "irq_create_mapping called for"
		       " NULL host, hwirq=%lx\n", hwirq);
		WARN_ON(1);
		return NO_IRQ;
	}
	pr_debug("irq: -> using host @%p\n", host);

	/* Check if mapping already exist, if it does, call
	 * host->ops->map() to update the flags
	 */
	virq = irq_find_mapping(host, hwirq);
	if (virq != NO_IRQ) {
		if (host->ops->remap)
			host->ops->remap(host, virq, hwirq);
		pr_debug("irq: -> existing mapping on virq %d\n", virq);
		return virq;
	}

	/* Get a virtual interrupt number */
	if (host->revmap_type == IRQ_HOST_MAP_LEGACY) {
		/* Handle legacy */
		virq = (unsigned int)hwirq;
		if (virq == 0 || virq >= NUM_ISA_INTERRUPTS)
			return NO_IRQ;
		return virq;
	} else {
		/* Allocate a virtual interrupt number */
		hint = hwirq % irq_virq_count;
		virq = irq_alloc_virt(host, 1, hint);
		if (virq == NO_IRQ) {
			pr_debug("irq: -> virq allocation failed\n");
			return NO_IRQ;
		}
	}

	if (irq_setup_virq(host, virq, hwirq))
		return NO_IRQ;

	printk(KERN_DEBUG "irq: irq %lu on host %s mapped to virtual irq %u\n",
		hwirq, host->of_node ? host->of_node->full_name : "null", virq);

	return virq;
}
EXPORT_SYMBOL_GPL(irq_create_mapping);

unsigned int irq_create_of_mapping(struct device_node *controller,
				   const u32 *intspec, unsigned int intsize)
{
	struct irq_host *host;
	irq_hw_number_t hwirq;
	unsigned int type = IRQ_TYPE_NONE;
	unsigned int virq;

	if (controller == NULL)
		host = irq_default_host;
	else
		host = irq_find_host(controller);
	if (host == NULL) {
		printk(KERN_WARNING "irq: no irq host found for %s !\n",
		       controller->full_name);
		return NO_IRQ;
	}

	/* If host has no translation, then we assume interrupt line */
	if (host->ops->xlate == NULL)
		hwirq = intspec[0];
	else {
		if (host->ops->xlate(host, controller, intspec, intsize,
				     &hwirq, &type))
			return NO_IRQ;
	}

	/* Create mapping */
	virq = irq_create_mapping(host, hwirq);
	if (virq == NO_IRQ)
		return virq;

	/* Set type if specified and different than the current one */
	if (type != IRQ_TYPE_NONE &&
	    type != (irq_to_desc(virq)->status & IRQF_TRIGGER_MASK))
		set_irq_type(virq, type);
	return virq;
}
EXPORT_SYMBOL_GPL(irq_create_of_mapping);

unsigned int irq_of_parse_and_map(struct device_node *dev, int index)
{
	struct of_irq oirq;

	if (of_irq_map_one(dev, index, &oirq))
		return NO_IRQ;

	return irq_create_of_mapping(oirq.controller, oirq.specifier,
				     oirq.size);
}
EXPORT_SYMBOL_GPL(irq_of_parse_and_map);

void irq_dispose_mapping(unsigned int virq)
{
	struct irq_host *host;
	irq_hw_number_t hwirq;

	if (virq == NO_IRQ)
		return;

	host = irq_map[virq].host;
	WARN_ON (host == NULL);
	if (host == NULL)
		return;

	/* Never unmap legacy interrupts */
	if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
		return;

	/* remove chip and handler */
	set_irq_chip_and_handler(virq, NULL, NULL);

	/* Make sure it's completed */
	synchronize_irq(virq);

	/* Tell the PIC about it */
	if (host->ops->unmap)
		host->ops->unmap(host, virq);
	smp_mb();

	/* Clear reverse map */
	hwirq = irq_map[virq].hwirq;
	switch(host->revmap_type) {
	case IRQ_HOST_MAP_LINEAR:
		if (hwirq < host->revmap_data.linear.size)
			host->revmap_data.linear.revmap[hwirq] = NO_IRQ;
		break;
	case IRQ_HOST_MAP_TREE:
		/*
		 * Check if radix tree allocated yet, if not then nothing to
		 * remove.
		 */
		smp_rmb();
		if (revmap_trees_allocated < 1)
			break;
		mutex_lock(&revmap_trees_mutex);
		radix_tree_delete(&host->revmap_data.tree, hwirq);
		mutex_unlock(&revmap_trees_mutex);
		break;
	}

	/* Destroy map */
	smp_mb();
	irq_map[virq].hwirq = host->inval_irq;

	/* Set some flags */
	irq_to_desc(virq)->status |= IRQ_NOREQUEST;

	/* Free it */
	irq_free_virt(virq, 1);
}
EXPORT_SYMBOL_GPL(irq_dispose_mapping);

unsigned int irq_find_mapping(struct irq_host *host,
			      irq_hw_number_t hwirq)
{
	unsigned int i;
	unsigned int hint = hwirq % irq_virq_count;

	/* Look for default host if nececssary */
	if (host == NULL)
		host = irq_default_host;
	if (host == NULL)
		return NO_IRQ;

	/* legacy -> bail early */
	if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
		return hwirq;

	/* Slow path does a linear search of the map */
	if (hint < NUM_ISA_INTERRUPTS)
		hint = NUM_ISA_INTERRUPTS;
	i = hint;
	do  {
		if (irq_map[i].host == host &&
		    irq_map[i].hwirq == hwirq)
			return i;
		i++;
		if (i >= irq_virq_count)
			i = NUM_ISA_INTERRUPTS;
	} while(i != hint);
	return NO_IRQ;
}
EXPORT_SYMBOL_GPL(irq_find_mapping);


unsigned int irq_radix_revmap_lookup(struct irq_host *host,
				     irq_hw_number_t hwirq)
{
	struct irq_map_entry *ptr;
	unsigned int virq;

	WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE);

	/*
	 * Check if the radix tree exists and has bee initialized.
	 * If not, we fallback to slow mode
	 */
	if (revmap_trees_allocated < 2)
		return irq_find_mapping(host, hwirq);

	/* Now try to resolve */
	/*
	 * No rcu_read_lock(ing) needed, the ptr returned can't go under us
	 * as it's referencing an entry in the static irq_map table.
	 */
	ptr = radix_tree_lookup(&host->revmap_data.tree, hwirq);

	/*
	 * If found in radix tree, then fine.
	 * Else fallback to linear lookup - this should not happen in practice
	 * as it means that we failed to insert the node in the radix tree.
	 */
	if (ptr)
		virq = ptr - irq_map;
	else
		virq = irq_find_mapping(host, hwirq);

	return virq;
}

void irq_radix_revmap_insert(struct irq_host *host, unsigned int virq,
			     irq_hw_number_t hwirq)
{

	WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE);

	/*
	 * Check if the radix tree exists yet.
	 * If not, then the irq will be inserted into the tree when it gets
	 * initialized.
	 */
	smp_rmb();
	if (revmap_trees_allocated < 1)
		return;

	if (virq != NO_IRQ) {
		mutex_lock(&revmap_trees_mutex);
		radix_tree_insert(&host->revmap_data.tree, hwirq,
				  &irq_map[virq]);
		mutex_unlock(&revmap_trees_mutex);
	}
}

unsigned int irq_linear_revmap(struct irq_host *host,
			       irq_hw_number_t hwirq)
{
	unsigned int *revmap;

	WARN_ON(host->revmap_type != IRQ_HOST_MAP_LINEAR);

	/* Check revmap bounds */
	if (unlikely(hwirq >= host->revmap_data.linear.size))
		return irq_find_mapping(host, hwirq);

	/* Check if revmap was allocated */
	revmap = host->revmap_data.linear.revmap;
	if (unlikely(revmap == NULL))
		return irq_find_mapping(host, hwirq);

	/* Fill up revmap with slow path if no mapping found */
	if (unlikely(revmap[hwirq] == NO_IRQ))
		revmap[hwirq] = irq_find_mapping(host, hwirq);

	return revmap[hwirq];
}

unsigned int irq_alloc_virt(struct irq_host *host,
			    unsigned int count,
			    unsigned int hint)
{
	unsigned long flags;
	unsigned int i, j, found = NO_IRQ;

	if (count == 0 || count > (irq_virq_count - NUM_ISA_INTERRUPTS))
		return NO_IRQ;

	raw_spin_lock_irqsave(&irq_big_lock, flags);

	/* Use hint for 1 interrupt if any */
	if (count == 1 && hint >= NUM_ISA_INTERRUPTS &&
	    hint < irq_virq_count && irq_map[hint].host == NULL) {
		found = hint;
		goto hint_found;
	}

	/* Look for count consecutive numbers in the allocatable
	 * (non-legacy) space
	 */
	for (i = NUM_ISA_INTERRUPTS, j = 0; i < irq_virq_count; i++) {
		if (irq_map[i].host != NULL)
			j = 0;
		else
			j++;

		if (j == count) {
			found = i - count + 1;
			break;
		}
	}
	if (found == NO_IRQ) {
		raw_spin_unlock_irqrestore(&irq_big_lock, flags);
		return NO_IRQ;
	}
 hint_found:
	for (i = found; i < (found + count); i++) {
		irq_map[i].hwirq = host->inval_irq;
		smp_wmb();
		irq_map[i].host = host;
	}
	raw_spin_unlock_irqrestore(&irq_big_lock, flags);
	return found;
}

void irq_free_virt(unsigned int virq, unsigned int count)
{
	unsigned long flags;
	unsigned int i;

	WARN_ON (virq < NUM_ISA_INTERRUPTS);
	WARN_ON (count == 0 || (virq + count) > irq_virq_count);

	raw_spin_lock_irqsave(&irq_big_lock, flags);
	for (i = virq; i < (virq + count); i++) {
		struct irq_host *host;

		if (i < NUM_ISA_INTERRUPTS ||
		    (virq + count) > irq_virq_count)
			continue;

		host = irq_map[i].host;
		irq_map[i].hwirq = host->inval_irq;
		smp_wmb();
		irq_map[i].host = NULL;
	}
	raw_spin_unlock_irqrestore(&irq_big_lock, flags);
}

int arch_early_irq_init(void)
{
	struct irq_desc *desc;
	int i;

	for (i = 0; i < NR_IRQS; i++) {
		desc = irq_to_desc(i);
		if (desc)
			desc->status |= IRQ_NOREQUEST;
	}

	return 0;
}

int arch_init_chip_data(struct irq_desc *desc, int node)
{
	desc->status |= IRQ_NOREQUEST;
	return 0;
}

/* We need to create the radix trees late */
static int irq_late_init(void)
{
	struct irq_host *h;
	unsigned int i;

	/*
	 * No mutual exclusion with respect to accessors of the tree is needed
	 * here as the synchronization is done via the state variable
	 * revmap_trees_allocated.
	 */
	list_for_each_entry(h, &irq_hosts, link) {
		if (h->revmap_type == IRQ_HOST_MAP_TREE)
			INIT_RADIX_TREE(&h->revmap_data.tree, GFP_KERNEL);
	}

	/*
	 * Make sure the radix trees inits are visible before setting
	 * the flag
	 */
	smp_wmb();
	revmap_trees_allocated = 1;

	/*
	 * Insert the reverse mapping for those interrupts already present
	 * in irq_map[].
	 */
	mutex_lock(&revmap_trees_mutex);
	for (i = 0; i < irq_virq_count; i++) {
		if (irq_map[i].host &&
		    (irq_map[i].host->revmap_type == IRQ_HOST_MAP_TREE))
			radix_tree_insert(&irq_map[i].host->revmap_data.tree,
					  irq_map[i].hwirq, &irq_map[i]);
	}
	mutex_unlock(&revmap_trees_mutex);

	/*
	 * Make sure the radix trees insertions are visible before setting
	 * the flag
	 */
	smp_wmb();
	revmap_trees_allocated = 2;

	return 0;
}
arch_initcall(irq_late_init);

#ifdef CONFIG_VIRQ_DEBUG
static int virq_debug_show(struct seq_file *m, void *private)
{
	unsigned long flags;
	struct irq_desc *desc;
	const char *p;
	char none[] = "none";
	int i;

	seq_printf(m, "%-5s  %-7s  %-15s  %s\n", "virq", "hwirq",
		      "chip name", "host name");

	for (i = 1; i < nr_irqs; i++) {
		desc = irq_to_desc(i);
		if (!desc)
			continue;

		raw_spin_lock_irqsave(&desc->lock, flags);

		if (desc->action && desc->action->handler) {
			seq_printf(m, "%5d  ", i);
			seq_printf(m, "0x%05lx  ", virq_to_hw(i));

			if (desc->chip && desc->chip->name)
				p = desc->chip->name;
			else
				p = none;
			seq_printf(m, "%-15s  ", p);

			if (irq_map[i].host && irq_map[i].host->of_node)
				p = irq_map[i].host->of_node->full_name;
			else
				p = none;
			seq_printf(m, "%s\n", p);
		}

		raw_spin_unlock_irqrestore(&desc->lock, flags);
	}

	return 0;
}

static int virq_debug_open(struct inode *inode, struct file *file)
{
	return single_open(file, virq_debug_show, inode->i_private);
}

static const struct file_operations virq_debug_fops = {
	.open = virq_debug_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static int __init irq_debugfs_init(void)
{
	if (debugfs_create_file("virq_mapping", S_IRUGO, powerpc_debugfs_root,
				 NULL, &virq_debug_fops) == NULL)
		return -ENOMEM;

	return 0;
}
__initcall(irq_debugfs_init);
#endif /* CONFIG_VIRQ_DEBUG */

#ifdef CONFIG_PPC64
static int __init setup_noirqdistrib(char *str)
{
	distribute_irqs = 0;
	return 1;
}

__setup("noirqdistrib", setup_noirqdistrib);
#endif /* CONFIG_PPC64 */