summaryrefslogtreecommitdiff
path: root/arch/m68k/atari/ataints.c
blob: bb54741dd6cd5d4358136f8c3fa42a2d77d371e0 (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
/*
 * arch/m68k/atari/ataints.c -- Atari Linux interrupt handling code
 *
 * 5/2/94 Roman Hodek:
 *  Added support for TT interrupts; setup for TT SCU (may someone has
 *  twiddled there and we won't get the right interrupts :-()
 *
 *  Major change: The device-independent code in m68k/ints.c didn't know
 *  about non-autovec ints yet. It hardcoded the number of possible ints to
 *  7 (IRQ1...IRQ7). But the Atari has lots of non-autovec ints! I made the
 *  number of possible ints a constant defined in interrupt.h, which is
 *  47 for the Atari. So we can call request_irq() for all Atari interrupts
 *  just the normal way. Additionally, all vectors >= 48 are initialized to
 *  call trap() instead of inthandler(). This must be changed here, too.
 *
 * 1995-07-16 Lars Brinkhoff <f93labr@dd.chalmers.se>:
 *  Corrected a bug in atari_add_isr() which rejected all SCC
 *  interrupt sources if there were no TT MFP!
 *
 * 12/13/95: New interface functions atari_level_triggered_int() and
 *  atari_register_vme_int() as support for level triggered VME interrupts.
 *
 * 02/12/96: (Roman)
 *  Total rewrite of Atari interrupt handling, for new scheme see comments
 *  below.
 *
 * 1996-09-03 lars brinkhoff <f93labr@dd.chalmers.se>:
 *  Added new function atari_unregister_vme_int(), and
 *  modified atari_register_vme_int() as well as IS_VALID_INTNO()
 *  to work with it.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 *
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/init.h>
#include <linux/seq_file.h>

#include <asm/system.h>
#include <asm/traps.h>

#include <asm/atarihw.h>
#include <asm/atariints.h>
#include <asm/atari_stdma.h>
#include <asm/irq.h>
#include <asm/entry.h>


/*
 * Atari interrupt handling scheme:
 * --------------------------------
 *
 * All interrupt source have an internal number (defined in
 * <asm/atariints.h>): Autovector interrupts are 1..7, then follow ST-MFP,
 * TT-MFP, SCC, and finally VME interrupts. Vector numbers for the latter can
 * be allocated by atari_register_vme_int().
 *
 * Each interrupt can be of three types:
 *
 *  - SLOW: The handler runs with all interrupts enabled, except the one it
 *    was called by (to avoid reentering). This should be the usual method.
 *    But it is currently possible only for MFP ints, since only the MFP
 *    offers an easy way to mask interrupts.
 *
 *  - FAST: The handler runs with all interrupts disabled. This should be used
 *    only for really fast handlers, that just do actions immediately
 *    necessary, and let the rest do a bottom half or task queue.
 *
 *  - PRIORITIZED: The handler can be interrupted by higher-level ints
 *    (greater IPL, no MFP priorities!). This is the method of choice for ints
 *    which should be slow, but are not from a MFP.
 *
 * The feature of more than one handler for one int source is still there, but
 * only applicable if all handers are of the same type. To not slow down
 * processing of ints with only one handler by the chaining feature, the list
 * calling function atari_call_irq_list() is only plugged in at the time the
 * second handler is registered.
 *
 * Implementation notes: For fast-as-possible int handling, there are separate
 * entry points for each type (slow/fast/prio). The assembler handler calls
 * the irq directly in the usual case, no C wrapper is involved. In case of
 * multiple handlers, atari_call_irq_list() is registered as handler and calls
 * in turn the real irq's. To ease access from assembler level to the irq
 * function pointer and accompanying data, these two are stored in a separate
 * array, irq_handler[]. The rest of data (type, name) are put into a second
 * array, irq_param, that is accessed from C only. For each slow interrupt (32
 * in all) there are separate handler functions, which makes it possible to
 * hard-code the MFP register address and value, are necessary to mask the
 * int. If there'd be only one generic function, lots of calculations would be
 * needed to determine MFP register and int mask from the vector number :-(
 *
 * Furthermore, slow ints may not lower the IPL below its previous value
 * (before the int happened). This is needed so that an int of class PRIO, on
 * that this int may be stacked, cannot be reentered. This feature is
 * implemented as follows: If the stack frame format is 1 (throwaway), the int
 * is not stacked, and the IPL is anded with 0xfbff, resulting in a new level
 * 2, which still blocks the HSYNC, but no interrupts of interest. If the
 * frame format is 0, the int is nested, and the old IPL value can be found in
 * the sr copy in the frame.
 */


#define	NUM_INT_SOURCES	(8 + NUM_ATARI_SOURCES)

typedef void (*asm_irq_handler)(void);

struct irqhandler {
	irqreturn_t (*handler)(int, void *, struct pt_regs *);
	void	*dev_id;
};

struct irqparam {
	unsigned long	flags;
	const char	*devname;
};

/*
 * Array with irq's and their parameter data. This array is accessed from low
 * level assembler code, so an element size of 8 allows usage of index scaling
 * addressing mode.
 */
static struct irqhandler irq_handler[NUM_INT_SOURCES];

/*
 * This array hold the rest of parameters of int handlers: type
 * (slow,fast,prio) and the name of the handler. These values are only
 * accessed from C
 */
static struct irqparam irq_param[NUM_INT_SOURCES];

/*
 * Bitmap for free interrupt vector numbers
 * (new vectors starting from 0x70 can be allocated by
 * atari_register_vme_int())
 */
static int free_vme_vec_bitmap;

/* check for valid int number (complex, sigh...) */
#define	IS_VALID_INTNO(n)											\
	((n) > 0 &&														\
	 /* autovec and ST-MFP ok anyway */								\
	 (((n) < TTMFP_SOURCE_BASE) ||									\
	  /* TT-MFP ok if present */									\
	  ((n) >= TTMFP_SOURCE_BASE && (n) < SCC_SOURCE_BASE &&			\
	   ATARIHW_PRESENT(TT_MFP)) ||									\
	  /* SCC ok if present and number even */						\
	  ((n) >= SCC_SOURCE_BASE && (n) < VME_SOURCE_BASE &&			\
	   !((n) & 1) && ATARIHW_PRESENT(SCC)) ||						\
	  /* greater numbers ok if they are registered VME vectors */		\
	  ((n) >= VME_SOURCE_BASE && (n) < VME_SOURCE_BASE + VME_MAX_SOURCES && \
		  free_vme_vec_bitmap & (1 << ((n) - VME_SOURCE_BASE)))))


/*
 * Here start the assembler entry points for interrupts
 */

#define IRQ_NAME(nr) atari_slow_irq_##nr##_handler(void)

#define	BUILD_SLOW_IRQ(n)						   \
asmlinkage void IRQ_NAME(n);						   \
/* Dummy function to allow asm with operands.  */			   \
void atari_slow_irq_##n##_dummy (void) {				   \
__asm__ (__ALIGN_STR "\n"						   \
"atari_slow_irq_" #n "_handler:\t"					   \
"	addl	%6,%5\n"	/* preempt_count() += HARDIRQ_OFFSET */	   \
	SAVE_ALL_INT "\n"						   \
	GET_CURRENT(%%d0) "\n"						   \
"	andb	#~(1<<(%c3&7)),%a4:w\n"	/* mask this interrupt */	   \
	/* get old IPL from stack frame */				   \
"	bfextu	%%sp@(%c2){#5,#3},%%d0\n"				   \
"	movew	%%sr,%%d1\n"						   \
"	bfins	%%d0,%%d1{#21,#3}\n"					   \
"	movew	%%d1,%%sr\n"		/* set IPL = previous value */	   \
"	addql	#1,%a0\n"						   \
"	lea	%a1,%%a0\n"						   \
"	pea	%%sp@\n"		/* push addr of frame */	   \
"	movel	%%a0@(4),%%sp@-\n"	/* push handler data */		   \
"	pea	(%c3+8)\n"		/* push int number */		   \
"	movel	%%a0@,%%a0\n"						   \
"	jbsr	%%a0@\n"		/* call the handler */		   \
"	addql	#8,%%sp\n"						   \
"	addql	#4,%%sp\n"						   \
"	orw	#0x0600,%%sr\n"						   \
"	andw	#0xfeff,%%sr\n"		/* set IPL = 6 again */		   \
"	orb	#(1<<(%c3&7)),%a4:w\n"	/* now unmask the int again */	   \
"	jbra	ret_from_interrupt\n"					   \
	 : : "i" (&kstat_cpu(0).irqs[n+8]), "i" (&irq_handler[n+8]),	   \
	     "n" (PT_OFF_SR), "n" (n),					   \
	     "i" (n & 8 ? (n & 16 ? &tt_mfp.int_mk_a : &mfp.int_mk_a)	   \
		        : (n & 16 ? &tt_mfp.int_mk_b : &mfp.int_mk_b)),	   \
	     "m" (preempt_count()), "di" (HARDIRQ_OFFSET)		   \
);									   \
	for (;;);			/* fake noreturn */		   \
}

BUILD_SLOW_IRQ(0);
BUILD_SLOW_IRQ(1);
BUILD_SLOW_IRQ(2);
BUILD_SLOW_IRQ(3);
BUILD_SLOW_IRQ(4);
BUILD_SLOW_IRQ(5);
BUILD_SLOW_IRQ(6);
BUILD_SLOW_IRQ(7);
BUILD_SLOW_IRQ(8);
BUILD_SLOW_IRQ(9);
BUILD_SLOW_IRQ(10);
BUILD_SLOW_IRQ(11);
BUILD_SLOW_IRQ(12);
BUILD_SLOW_IRQ(13);
BUILD_SLOW_IRQ(14);
BUILD_SLOW_IRQ(15);
BUILD_SLOW_IRQ(16);
BUILD_SLOW_IRQ(17);
BUILD_SLOW_IRQ(18);
BUILD_SLOW_IRQ(19);
BUILD_SLOW_IRQ(20);
BUILD_SLOW_IRQ(21);
BUILD_SLOW_IRQ(22);
BUILD_SLOW_IRQ(23);
BUILD_SLOW_IRQ(24);
BUILD_SLOW_IRQ(25);
BUILD_SLOW_IRQ(26);
BUILD_SLOW_IRQ(27);
BUILD_SLOW_IRQ(28);
BUILD_SLOW_IRQ(29);
BUILD_SLOW_IRQ(30);
BUILD_SLOW_IRQ(31);

asm_irq_handler slow_handlers[32] = {
	[0]	= atari_slow_irq_0_handler,
	[1]	= atari_slow_irq_1_handler,
	[2]	= atari_slow_irq_2_handler,
	[3]	= atari_slow_irq_3_handler,
	[4]	= atari_slow_irq_4_handler,
	[5]	= atari_slow_irq_5_handler,
	[6]	= atari_slow_irq_6_handler,
	[7]	= atari_slow_irq_7_handler,
	[8]	= atari_slow_irq_8_handler,
	[9]	= atari_slow_irq_9_handler,
	[10]	= atari_slow_irq_10_handler,
	[11]	= atari_slow_irq_11_handler,
	[12]	= atari_slow_irq_12_handler,
	[13]	= atari_slow_irq_13_handler,
	[14]	= atari_slow_irq_14_handler,
	[15]	= atari_slow_irq_15_handler,
	[16]	= atari_slow_irq_16_handler,
	[17]	= atari_slow_irq_17_handler,
	[18]	= atari_slow_irq_18_handler,
	[19]	= atari_slow_irq_19_handler,
	[20]	= atari_slow_irq_20_handler,
	[21]	= atari_slow_irq_21_handler,
	[22]	= atari_slow_irq_22_handler,
	[23]	= atari_slow_irq_23_handler,
	[24]	= atari_slow_irq_24_handler,
	[25]	= atari_slow_irq_25_handler,
	[26]	= atari_slow_irq_26_handler,
	[27]	= atari_slow_irq_27_handler,
	[28]	= atari_slow_irq_28_handler,
	[29]	= atari_slow_irq_29_handler,
	[30]	= atari_slow_irq_30_handler,
	[31]	= atari_slow_irq_31_handler
};

asmlinkage void atari_fast_irq_handler( void );
asmlinkage void atari_prio_irq_handler( void );

/* Dummy function to allow asm with operands.  */
void atari_fast_prio_irq_dummy (void) {
__asm__ (__ALIGN_STR "\n"
"atari_fast_irq_handler:\n\t"
	"orw	#0x700,%%sr\n"		/* disable all interrupts */
"atari_prio_irq_handler:\n\t"
	"addl	%3,%2\n\t"		/* preempt_count() += HARDIRQ_OFFSET */
	SAVE_ALL_INT "\n\t"
	GET_CURRENT(%%d0) "\n\t"
	/* get vector number from stack frame and convert to source */
	"bfextu	%%sp@(%c1){#4,#10},%%d0\n\t"
	"subw	#(0x40-8),%%d0\n\t"
	"jpl	1f\n\t"
	"addw	#(0x40-8-0x18),%%d0\n"
    "1:\tlea	%a0,%%a0\n\t"
	"addql	#1,%%a0@(%%d0:l:4)\n\t"
	"lea	irq_handler,%%a0\n\t"
	"lea	%%a0@(%%d0:l:8),%%a0\n\t"
	"pea	%%sp@\n\t"		/* push frame address */
	"movel	%%a0@(4),%%sp@-\n\t"	/* push handler data */
	"movel	%%d0,%%sp@-\n\t"	/* push int number */
	"movel	%%a0@,%%a0\n\t"
	"jsr	%%a0@\n\t"		/* and call the handler */
	"addql	#8,%%sp\n\t"
	"addql	#4,%%sp\n\t"
	"jbra	ret_from_interrupt"
	 : : "i" (&kstat_cpu(0).irqs), "n" (PT_OFF_FORMATVEC),
	     "m" (preempt_count()), "di" (HARDIRQ_OFFSET)
);
	for (;;);
}

/* GK:
 * HBL IRQ handler for Falcon. Nobody needs it :-)
 * ++andreas: raise ipl to disable further HBLANK interrupts.
 */
asmlinkage void falcon_hblhandler(void);
asm(".text\n"
__ALIGN_STR "\n\t"
"falcon_hblhandler:\n\t"
	"orw	#0x200,%sp@\n\t"	/* set saved ipl to 2 */
	"rte");

/* Defined in entry.S; only increments 'num_spurious' */
asmlinkage void bad_inthandler(void);

extern void atari_microwire_cmd( int cmd );

extern int atari_SCC_reset_done;

/*
 * void atari_init_IRQ (void)
 *
 * Parameters:	None
 *
 * Returns:	Nothing
 *
 * This function should be called during kernel startup to initialize
 * the atari IRQ handling routines.
 */

void __init atari_init_IRQ(void)
{
	int i;

	/* initialize the vector table */
	for (i = 0; i < NUM_INT_SOURCES; ++i) {
		vectors[IRQ_SOURCE_TO_VECTOR(i)] = bad_inthandler;
	}

	/* Initialize the MFP(s) */

#ifdef ATARI_USE_SOFTWARE_EOI
	mfp.vec_adr  = 0x48;	/* Software EOI-Mode */
#else
	mfp.vec_adr  = 0x40;	/* Automatic EOI-Mode */
#endif
	mfp.int_en_a = 0x00;	/* turn off MFP-Ints */
	mfp.int_en_b = 0x00;
	mfp.int_mk_a = 0xff;	/* no Masking */
	mfp.int_mk_b = 0xff;

	if (ATARIHW_PRESENT(TT_MFP)) {
#ifdef ATARI_USE_SOFTWARE_EOI
		tt_mfp.vec_adr  = 0x58;		/* Software EOI-Mode */
#else
		tt_mfp.vec_adr  = 0x50;		/* Automatic EOI-Mode */
#endif
		tt_mfp.int_en_a = 0x00;		/* turn off MFP-Ints */
		tt_mfp.int_en_b = 0x00;
		tt_mfp.int_mk_a = 0xff;		/* no Masking */
		tt_mfp.int_mk_b = 0xff;
	}

	if (ATARIHW_PRESENT(SCC) && !atari_SCC_reset_done) {
		scc.cha_a_ctrl = 9;
		MFPDELAY();
		scc.cha_a_ctrl = (char) 0xc0; /* hardware reset */
	}

	if (ATARIHW_PRESENT(SCU)) {
		/* init the SCU if present */
		tt_scu.sys_mask = 0x10;		/* enable VBL (for the cursor) and
									 * disable HSYNC interrupts (who
									 * needs them?)  MFP and SCC are
									 * enabled in VME mask
									 */
		tt_scu.vme_mask = 0x60;		/* enable MFP and SCC ints */
	}
	else {
		/* If no SCU and no Hades, the HSYNC interrupt needs to be
		 * disabled this way. (Else _inthandler in kernel/sys_call.S
		 * gets overruns)
		 */

		if (!MACH_IS_HADES)
			vectors[VEC_INT2] = falcon_hblhandler;
	}

	if (ATARIHW_PRESENT(PCM_8BIT) && ATARIHW_PRESENT(MICROWIRE)) {
		/* Initialize the LM1992 Sound Controller to enable
		   the PSG sound.  This is misplaced here, it should
		   be in an atasound_init(), that doesn't exist yet. */
		atari_microwire_cmd(MW_LM1992_PSG_HIGH);
	}

	stdma_init();

	/* Initialize the PSG: all sounds off, both ports output */
	sound_ym.rd_data_reg_sel = 7;
	sound_ym.wd_data = 0xff;
}


static irqreturn_t atari_call_irq_list( int irq, void *dev_id, struct pt_regs *fp )
{
	irq_node_t *node;

	for (node = (irq_node_t *)dev_id; node; node = node->next)
		node->handler(irq, node->dev_id, fp);
	return IRQ_HANDLED;
}


/*
 * atari_request_irq : add an interrupt service routine for a particular
 *                     machine specific interrupt source.
 *                     If the addition was successful, it returns 0.
 */

int atari_request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
                      unsigned long flags, const char *devname, void *dev_id)
{
	int vector;
	unsigned long oflags = flags;

	/*
	 * The following is a hack to make some PCI card drivers work,
	 * which set the SA_SHIRQ flag.
	 */

	flags &= ~SA_SHIRQ;

	if (flags == SA_INTERRUPT) {
		printk ("%s: SA_INTERRUPT changed to IRQ_TYPE_SLOW for %s\n",
			__FUNCTION__, devname);
		flags = IRQ_TYPE_SLOW;
	}
	if (flags < IRQ_TYPE_SLOW || flags > IRQ_TYPE_PRIO) {
		printk ("%s: Bad irq type 0x%lx <0x%lx> requested from %s\n",
		        __FUNCTION__, flags, oflags, devname);
		return -EINVAL;
	}
	if (!IS_VALID_INTNO(irq)) {
		printk ("%s: Unknown irq %d requested from %s\n",
		        __FUNCTION__, irq, devname);
		return -ENXIO;
	}
	vector = IRQ_SOURCE_TO_VECTOR(irq);

	/*
	 * Check type/source combination: slow ints are (currently)
	 * only possible for MFP-interrupts.
	 */
	if (flags == IRQ_TYPE_SLOW &&
		(irq < STMFP_SOURCE_BASE || irq >= SCC_SOURCE_BASE)) {
		printk ("%s: Slow irq requested for non-MFP source %d from %s\n",
		        __FUNCTION__, irq, devname);
		return -EINVAL;
	}

	if (vectors[vector] == bad_inthandler) {
		/* int has no handler yet */
		irq_handler[irq].handler = handler;
		irq_handler[irq].dev_id  = dev_id;
		irq_param[irq].flags   = flags;
		irq_param[irq].devname = devname;
		vectors[vector] =
			(flags == IRQ_TYPE_SLOW) ? slow_handlers[irq-STMFP_SOURCE_BASE] :
			(flags == IRQ_TYPE_FAST) ? atari_fast_irq_handler :
			                          atari_prio_irq_handler;
		/* If MFP int, also enable and umask it */
		atari_turnon_irq(irq);
		atari_enable_irq(irq);

		return 0;
	}
	else if (irq_param[irq].flags == flags) {
		/* old handler is of same type -> handlers can be chained */
		irq_node_t *node;
		unsigned long flags;

		local_irq_save(flags);

		if (irq_handler[irq].handler != atari_call_irq_list) {
			/* Only one handler yet, make a node for this first one */
			if (!(node = new_irq_node()))
				return -ENOMEM;
			node->handler = irq_handler[irq].handler;
			node->dev_id  = irq_handler[irq].dev_id;
			node->devname = irq_param[irq].devname;
			node->next = NULL;

			irq_handler[irq].handler = atari_call_irq_list;
			irq_handler[irq].dev_id  = node;
			irq_param[irq].devname   = "chained";
		}

		if (!(node = new_irq_node()))
			return -ENOMEM;
		node->handler = handler;
		node->dev_id  = dev_id;
		node->devname = devname;
		/* new handlers are put in front of the queue */
		node->next = irq_handler[irq].dev_id;
		irq_handler[irq].dev_id = node;

		local_irq_restore(flags);
		return 0;
	} else {
		printk ("%s: Irq %d allocated by other type int (call from %s)\n",
		        __FUNCTION__, irq, devname);
		return -EBUSY;
	}
}

void atari_free_irq(unsigned int irq, void *dev_id)
{
	unsigned long flags;
	int vector;
	irq_node_t **list, *node;

	if (!IS_VALID_INTNO(irq)) {
		printk("%s: Unknown irq %d\n", __FUNCTION__, irq);
		return;
	}

	vector = IRQ_SOURCE_TO_VECTOR(irq);
	if (vectors[vector] == bad_inthandler)
		goto not_found;

	local_irq_save(flags);

	if (irq_handler[irq].handler != atari_call_irq_list) {
		/* It's the only handler for the interrupt */
		if (irq_handler[irq].dev_id != dev_id) {
			local_irq_restore(flags);
			goto not_found;
		}
		irq_handler[irq].handler = NULL;
		irq_handler[irq].dev_id  = NULL;
		irq_param[irq].devname   = NULL;
		vectors[vector] = bad_inthandler;
		/* If MFP int, also disable it */
		atari_disable_irq(irq);
		atari_turnoff_irq(irq);

		local_irq_restore(flags);
		return;
	}

	/* The interrupt is chained, find the irq on the list */
	for(list = (irq_node_t **)&irq_handler[irq].dev_id; *list; list = &(*list)->next) {
		if ((*list)->dev_id == dev_id) break;
	}
	if (!*list) {
		local_irq_restore(flags);
		goto not_found;
	}

	(*list)->handler = NULL; /* Mark it as free for reallocation */
	*list = (*list)->next;

	/* If there's now only one handler, unchain the interrupt, i.e. plug in
	 * the handler directly again and omit atari_call_irq_list */
	node = (irq_node_t *)irq_handler[irq].dev_id;
	if (node && !node->next) {
		irq_handler[irq].handler = node->handler;
		irq_handler[irq].dev_id  = node->dev_id;
		irq_param[irq].devname   = node->devname;
		node->handler = NULL; /* Mark it as free for reallocation */
	}

	local_irq_restore(flags);
	return;

not_found:
	printk("%s: tried to remove invalid irq\n", __FUNCTION__);
	return;
}


/*
 * atari_register_vme_int() returns the number of a free interrupt vector for
 * hardware with a programmable int vector (probably a VME board).
 */

unsigned long atari_register_vme_int(void)
{
	int i;

	for(i = 0; i < 32; i++)
		if((free_vme_vec_bitmap & (1 << i)) == 0)
			break;

	if(i == 16)
		return 0;

	free_vme_vec_bitmap |= 1 << i;
	return (VME_SOURCE_BASE + i);
}


void atari_unregister_vme_int(unsigned long irq)
{
	if(irq >= VME_SOURCE_BASE && irq < VME_SOURCE_BASE + VME_MAX_SOURCES) {
		irq -= VME_SOURCE_BASE;
		free_vme_vec_bitmap &= ~(1 << irq);
	}
}


int show_atari_interrupts(struct seq_file *p, void *v)
{
	int i;

	for (i = 0; i < NUM_INT_SOURCES; ++i) {
		if (vectors[IRQ_SOURCE_TO_VECTOR(i)] == bad_inthandler)
			continue;
		if (i < STMFP_SOURCE_BASE)
			seq_printf(p, "auto %2d: %10u ",
				       i, kstat_cpu(0).irqs[i]);
		else
			seq_printf(p, "vec $%02x: %10u ",
				       IRQ_SOURCE_TO_VECTOR(i),
				       kstat_cpu(0).irqs[i]);

		if (irq_handler[i].handler != atari_call_irq_list) {
			seq_printf(p, "%s\n", irq_param[i].devname);
		}
		else {
			irq_node_t *n;
			for( n = (irq_node_t *)irq_handler[i].dev_id; n; n = n->next ) {
				seq_printf(p, "%s\n", n->devname);
				if (n->next)
					seq_puts(p, "                    " );
			}
		}
	}
	if (num_spurious)
		seq_printf(p, "spurio.: %10u\n", num_spurious);

	return 0;
}