File: /usr/src/linux/arch/m68k/atari/ataints.c

1     /*
2      * arch/m68k/atari/ataints.c -- Atari Linux interrupt handling code
3      *
4      * 5/2/94 Roman Hodek:
5      *  Added support for TT interrupts; setup for TT SCU (may someone has
6      *  twiddled there and we won't get the right interrupts :-()
7      *
8      *  Major change: The device-independent code in m68k/ints.c didn't know
9      *  about non-autovec ints yet. It hardcoded the number of possible ints to
10      *  7 (IRQ1...IRQ7). But the Atari has lots of non-autovec ints! I made the
11      *  number of possible ints a constant defined in interrupt.h, which is
12      *  47 for the Atari. So we can call request_irq() for all Atari interrupts
13      *  just the normal way. Additionally, all vectors >= 48 are initialized to
14      *  call trap() instead of inthandler(). This must be changed here, too.
15      *
16      * 1995-07-16 Lars Brinkhoff <f93labr@dd.chalmers.se>:
17      *  Corrected a bug in atari_add_isr() which rejected all SCC
18      *  interrupt sources if there were no TT MFP!
19      *
20      * 12/13/95: New interface functions atari_level_triggered_int() and
21      *  atari_register_vme_int() as support for level triggered VME interrupts.
22      *
23      * 02/12/96: (Roman)
24      *  Total rewrite of Atari interrupt handling, for new scheme see comments
25      *  below.
26      *
27      * 1996-09-03 lars brinkhoff <f93labr@dd.chalmers.se>:
28      *  Added new function atari_unregister_vme_int(), and
29      *  modified atari_register_vme_int() as well as IS_VALID_INTNO()
30      *  to work with it.
31      *
32      * This file is subject to the terms and conditions of the GNU General Public
33      * License.  See the file COPYING in the main directory of this archive
34      * for more details.
35      *
36      */
37     
38     #include <linux/types.h>
39     #include <linux/kernel.h>
40     #include <linux/ptrace.h>
41     #include <linux/kernel_stat.h>
42     #include <linux/init.h>
43     
44     #include <asm/system.h>
45     #include <asm/traps.h>
46     
47     #include <asm/atarihw.h>
48     #include <asm/atariints.h>
49     #include <asm/atari_stdma.h>
50     #include <asm/irq.h>
51     #include <asm/entry.h>
52     
53     
54     /*
55      * Atari interrupt handling scheme:
56      * --------------------------------
57      * 
58      * All interrupt source have an internal number (defined in
59      * <asm/atariints.h>): Autovector interrupts are 1..7, then follow ST-MFP,
60      * TT-MFP, SCC, and finally VME interrupts. Vector numbers for the latter can
61      * be allocated by atari_register_vme_int().
62      *
63      * Each interrupt can be of three types:
64      * 
65      *  - SLOW: The handler runs with all interrupts enabled, except the one it
66      *    was called by (to avoid reentering). This should be the usual method.
67      *    But it is currently possible only for MFP ints, since only the MFP
68      *    offers an easy way to mask interrupts.
69      *
70      *  - FAST: The handler runs with all interrupts disabled. This should be used
71      *    only for really fast handlers, that just do actions immediately
72      *    necessary, and let the rest do a bottom half or task queue.
73      *
74      *  - PRIORITIZED: The handler can be interrupted by higher-level ints
75      *    (greater IPL, no MFP priorities!). This is the method of choice for ints
76      *    which should be slow, but are not from a MFP.
77      *
78      * The feature of more than one handler for one int source is still there, but
79      * only applicable if all handers are of the same type. To not slow down
80      * processing of ints with only one handler by the chaining feature, the list
81      * calling function atari_call_irq_list() is only plugged in at the time the
82      * second handler is registered.
83      *
84      * Implementation notes: For fast-as-possible int handling, there are separate
85      * entry points for each type (slow/fast/prio). The assembler handler calls
86      * the irq directly in the usual case, no C wrapper is involved. In case of
87      * multiple handlers, atari_call_irq_list() is registered as handler and calls
88      * in turn the real irq's. To ease access from assembler level to the irq
89      * function pointer and accompanying data, these two are stored in a separate
90      * array, irq_handler[]. The rest of data (type, name) are put into a second
91      * array, irq_param, that is accessed from C only. For each slow interrupt (32
92      * in all) there are separate handler functions, which makes it possible to
93      * hard-code the MFP register address and value, are necessary to mask the
94      * int. If there'd be only one generic function, lots of calculations would be
95      * needed to determine MFP register and int mask from the vector number :-(
96      *
97      * Furthermore, slow ints may not lower the IPL below its previous value
98      * (before the int happened). This is needed so that an int of class PRIO, on
99      * that this int may be stacked, cannot be reentered. This feature is
100      * implemented as follows: If the stack frame format is 1 (throwaway), the int
101      * is not stacked, and the IPL is anded with 0xfbff, resulting in a new level
102      * 2, which still blocks the HSYNC, but no interrupts of interest. If the
103      * frame format is 0, the int is nested, and the old IPL value can be found in
104      * the sr copy in the frame.
105      */
106     
107     
108     #define	NUM_INT_SOURCES	(8 + NUM_ATARI_SOURCES)
109     
110     typedef void (*asm_irq_handler)(void);
111     
112     struct irqhandler {
113     	void	(*handler)(int, void *, struct pt_regs *);
114     	void	*dev_id;
115     };
116     
117     struct irqparam {
118     	unsigned long	flags;
119     	const char	*devname;
120     };
121     
122     /*
123      * Array with irq's and their parameter data. This array is accessed from low
124      * level assembler code, so an element size of 8 allows usage of index scaling
125      * addressing mode.
126      */
127     static struct irqhandler irq_handler[NUM_INT_SOURCES];
128     
129     /*
130      * This array hold the rest of parameters of int handlers: type
131      * (slow,fast,prio) and the name of the handler. These values are only
132      * accessed from C
133      */
134     static struct irqparam irq_param[NUM_INT_SOURCES];
135     
136     /*
137      * Bitmap for free interrupt vector numbers
138      * (new vectors starting from 0x70 can be allocated by
139      * atari_register_vme_int())
140      */
141     static int free_vme_vec_bitmap = 0;
142     
143     /* check for valid int number (complex, sigh...) */
144     #define	IS_VALID_INTNO(n)											\
145     	((n) > 0 &&														\
146     	 /* autovec and ST-MFP ok anyway */								\
147     	 (((n) < TTMFP_SOURCE_BASE) ||									\
148     	  /* TT-MFP ok if present */									\
149     	  ((n) >= TTMFP_SOURCE_BASE && (n) < SCC_SOURCE_BASE &&			\
150     	   ATARIHW_PRESENT(TT_MFP)) ||									\
151     	  /* SCC ok if present and number even */						\
152     	  ((n) >= SCC_SOURCE_BASE && (n) < VME_SOURCE_BASE &&			\
153     	   !((n) & 1) && ATARIHW_PRESENT(SCC)) ||						\
154     	  /* greater numbers ok if they are registered VME vectors */		\
155     	  ((n) >= VME_SOURCE_BASE && (n) < VME_SOURCE_BASE + VME_MAX_SOURCES && \
156     		  free_vme_vec_bitmap & (1 << ((n) - VME_SOURCE_BASE)))))
157     
158     
159     /*
160      * Here start the assembler entry points for interrupts
161      */
162     
163     #define IRQ_NAME(nr) atari_slow_irq_##nr##_handler(void)
164     
165     #define	BUILD_SLOW_IRQ(n)						   \
166     asmlinkage void IRQ_NAME(n);						   \
167     /* Dummy function to allow asm with operands.  */			   \
168     void atari_slow_irq_##n##_dummy (void) {				   \
169     __asm__ (__ALIGN_STR "\n"						   \
170     SYMBOL_NAME_STR(atari_slow_irq_) #n "_handler:\t"			   \
171     "	addql	#1,"SYMBOL_NAME_STR(irq_stat)"+8\n" /* local_irq_count */  \
172     	SAVE_ALL_INT "\n"						   \
173     	GET_CURRENT(%%d0) "\n"						   \
174     "	andb	#~(1<<(%c3&7)),%a4:w\n"	/* mask this interrupt */	   \
175     	/* get old IPL from stack frame */				   \
176     "	bfextu	%%sp@(%c2){#5,#3},%%d0\n"				   \
177     "	movew	%%sr,%%d1\n"						   \
178     "	bfins	%%d0,%%d1{#21,#3}\n"					   \
179     "	movew	%%d1,%%sr\n"		/* set IPL = previous value */	   \
180     "	addql	#1,%a0\n"						   \
181     "	lea	%a1,%%a0\n"						   \
182     "	pea 	%%sp@\n"		/* push addr of frame */	   \
183     "	movel	%%a0@(4),%%sp@-\n"	/* push handler data */		   \
184     "	pea 	(%c3+8)\n"		/* push int number */		   \
185     "	movel	%%a0@,%%a0\n"						   \
186     "	jbsr	%%a0@\n"		/* call the handler */		   \
187     "	addql	#8,%%sp\n"						   \
188     "	addql	#4,%%sp\n"						   \
189     "	orw	#0x0600,%%sr\n"						   \
190     "	andw	#0xfeff,%%sr\n"		/* set IPL = 6 again */		   \
191     "	orb 	#(1<<(%c3&7)),%a4:w\n"	/* now unmask the int again */	   \
192     "	jbra	"SYMBOL_NAME_STR(ret_from_interrupt)"\n"		   \
193     	 : : "i" (&kstat.irqs[0][n+8]), "i" (&irq_handler[n+8]),	   \
194     	     "n" (PT_OFF_SR), "n" (n),					   \
195     	     "i" (n & 8 ? (n & 16 ? &tt_mfp.int_mk_a : &mfp.int_mk_a)	   \
196     		        : (n & 16 ? &tt_mfp.int_mk_b : &mfp.int_mk_b))	   \
197     );									   \
198     }
199     
200     BUILD_SLOW_IRQ(0);
201     BUILD_SLOW_IRQ(1);
202     BUILD_SLOW_IRQ(2);
203     BUILD_SLOW_IRQ(3);
204     BUILD_SLOW_IRQ(4);
205     BUILD_SLOW_IRQ(5);
206     BUILD_SLOW_IRQ(6);
207     BUILD_SLOW_IRQ(7);
208     BUILD_SLOW_IRQ(8);
209     BUILD_SLOW_IRQ(9);
210     BUILD_SLOW_IRQ(10);
211     BUILD_SLOW_IRQ(11);
212     BUILD_SLOW_IRQ(12);
213     BUILD_SLOW_IRQ(13);
214     BUILD_SLOW_IRQ(14);
215     BUILD_SLOW_IRQ(15);
216     BUILD_SLOW_IRQ(16);
217     BUILD_SLOW_IRQ(17);
218     BUILD_SLOW_IRQ(18);
219     BUILD_SLOW_IRQ(19);
220     BUILD_SLOW_IRQ(20);
221     BUILD_SLOW_IRQ(21);
222     BUILD_SLOW_IRQ(22);
223     BUILD_SLOW_IRQ(23);
224     BUILD_SLOW_IRQ(24);
225     BUILD_SLOW_IRQ(25);
226     BUILD_SLOW_IRQ(26);
227     BUILD_SLOW_IRQ(27);
228     BUILD_SLOW_IRQ(28);
229     BUILD_SLOW_IRQ(29);
230     BUILD_SLOW_IRQ(30);
231     BUILD_SLOW_IRQ(31);
232     
233     asm_irq_handler slow_handlers[32] = {
234     	atari_slow_irq_0_handler,
235     	atari_slow_irq_1_handler,
236     	atari_slow_irq_2_handler,
237     	atari_slow_irq_3_handler,
238     	atari_slow_irq_4_handler,
239     	atari_slow_irq_5_handler,
240     	atari_slow_irq_6_handler,
241     	atari_slow_irq_7_handler,
242     	atari_slow_irq_8_handler,
243     	atari_slow_irq_9_handler,
244     	atari_slow_irq_10_handler,
245     	atari_slow_irq_11_handler,
246     	atari_slow_irq_12_handler,
247     	atari_slow_irq_13_handler,
248     	atari_slow_irq_14_handler,
249     	atari_slow_irq_15_handler,
250     	atari_slow_irq_16_handler,
251     	atari_slow_irq_17_handler,
252     	atari_slow_irq_18_handler,
253     	atari_slow_irq_19_handler,
254     	atari_slow_irq_20_handler,
255     	atari_slow_irq_21_handler,
256     	atari_slow_irq_22_handler,
257     	atari_slow_irq_23_handler,
258     	atari_slow_irq_24_handler,
259     	atari_slow_irq_25_handler,
260     	atari_slow_irq_26_handler,
261     	atari_slow_irq_27_handler,
262     	atari_slow_irq_28_handler,
263     	atari_slow_irq_29_handler,
264     	atari_slow_irq_30_handler,
265     	atari_slow_irq_31_handler
266     };
267     
268     asmlinkage void atari_fast_irq_handler( void );
269     asmlinkage void atari_prio_irq_handler( void );
270     
271     /* Dummy function to allow asm with operands.  */
272     void atari_fast_prio_irq_dummy (void) {
273     __asm__ (__ALIGN_STR "\n"
274     SYMBOL_NAME_STR(atari_fast_irq_handler) ":
275     	orw 	#0x700,%%sr		/* disable all interrupts */
276     "SYMBOL_NAME_STR(atari_prio_irq_handler) ":\t
277     	addql	#1,"SYMBOL_NAME_STR(irq_stat)"+8\n" /* local_irq_count */
278     	SAVE_ALL_INT "\n"
279     	GET_CURRENT(%%d0) "
280     	/* get vector number from stack frame and convert to source */
281     	bfextu	%%sp@(%c1){#4,#10},%%d0
282     	subw	#(0x40-8),%%d0
283     	jpl 	1f
284     	addw	#(0x40-8-0x18),%%d0
285     1:	lea	%a0,%%a0
286     	addql	#1,%%a0@(%%d0:l:4)
287     	lea	"SYMBOL_NAME_STR(irq_handler)",%%a0
288     	lea	%%a0@(%%d0:l:8),%%a0
289     	pea 	%%sp@			/* push frame address */
290     	movel	%%a0@(4),%%sp@-		/* push handler data */
291     	movel	%%d0,%%sp@-		/* push int number */
292     	movel	%%a0@,%%a0
293     	jsr	%%a0@			/* and call the handler */
294     	addql	#8,%%sp
295     	addql	#4,%%sp
296     	jbra	"SYMBOL_NAME_STR(ret_from_interrupt)
297     	 : : "i" (&kstat.irqs[0]), "n" (PT_OFF_FORMATVEC)
298     );
299     }
300     
301     /* GK:
302      * HBL IRQ handler for Falcon. Nobody needs it :-)
303      * ++andreas: raise ipl to disable further HBLANK interrupts.
304      */
305     asmlinkage void falcon_hblhandler(void);
306     asm(".text\n"
307     __ALIGN_STR "\n"
308     SYMBOL_NAME_STR(falcon_hblhandler) ":
309     	orw	#0x200,%sp@	/* set saved ipl to 2 */
310     	rte");
311     
312     /* Defined in entry.S; only increments 'num_spurious' */
313     asmlinkage void bad_interrupt(void);
314     
315     extern void atari_microwire_cmd( int cmd );
316     
317     extern int atari_SCC_reset_done;
318     
319     /*
320      * void atari_init_IRQ (void)
321      *
322      * Parameters:	None
323      *
324      * Returns:	Nothing
325      *
326      * This function should be called during kernel startup to initialize
327      * the atari IRQ handling routines.
328      */
329     
330     void __init atari_init_IRQ(void)
331     {
332     	int i;
333     
334     	/* initialize the vector table */
335     	for (i = 0; i < NUM_INT_SOURCES; ++i) {
336     		vectors[IRQ_SOURCE_TO_VECTOR(i)] = bad_interrupt;
337     	}
338     
339     	/* Initialize the MFP(s) */
340     
341     #ifdef ATARI_USE_SOFTWARE_EOI
342     	mfp.vec_adr  = 0x48;	/* Software EOI-Mode */
343     #else
344     	mfp.vec_adr  = 0x40;	/* Automatic EOI-Mode */
345     #endif
346     	mfp.int_en_a = 0x00;	/* turn off MFP-Ints */
347     	mfp.int_en_b = 0x00;
348     	mfp.int_mk_a = 0xff;	/* no Masking */
349     	mfp.int_mk_b = 0xff;
350     
351     	if (ATARIHW_PRESENT(TT_MFP)) {
352     #ifdef ATARI_USE_SOFTWARE_EOI
353     		tt_mfp.vec_adr  = 0x58;		/* Software EOI-Mode */
354     #else
355     		tt_mfp.vec_adr  = 0x50;		/* Automatic EOI-Mode */
356     #endif
357     		tt_mfp.int_en_a = 0x00;		/* turn off MFP-Ints */
358     		tt_mfp.int_en_b = 0x00;
359     		tt_mfp.int_mk_a = 0xff;		/* no Masking */
360     		tt_mfp.int_mk_b = 0xff;
361     	}
362     
363     	if (ATARIHW_PRESENT(SCC) && !atari_SCC_reset_done) {
364     		scc.cha_a_ctrl = 9;
365     		MFPDELAY();
366     		scc.cha_a_ctrl = (char) 0xc0; /* hardware reset */
367     	}
368     
369     	if (ATARIHW_PRESENT(SCU)) {
370     		/* init the SCU if present */
371     		tt_scu.sys_mask = 0x10;		/* enable VBL (for the cursor) and
372     									 * disable HSYNC interrupts (who
373     									 * needs them?)  MFP and SCC are
374     									 * enabled in VME mask
375     									 */
376     		tt_scu.vme_mask = 0x60;		/* enable MFP and SCC ints */
377     	}
378     	else {
379     		/* If no SCU and no Hades, the HSYNC interrupt needs to be
380     		 * disabled this way. (Else _inthandler in kernel/sys_call.S
381     		 * gets overruns)
382     		 */
383     
384     		if (!MACH_IS_HADES)
385     			vectors[VEC_INT2] = falcon_hblhandler;
386     	}
387     
388     	if (ATARIHW_PRESENT(PCM_8BIT) && ATARIHW_PRESENT(MICROWIRE)) {
389     		/* Initialize the LM1992 Sound Controller to enable
390     		   the PSG sound.  This is misplaced here, it should
391     		   be in an atasound_init(), that doesn't exist yet. */
392     		atari_microwire_cmd(MW_LM1992_PSG_HIGH);
393     	}
394     	
395     	stdma_init();
396     
397     	/* Initialize the PSG: all sounds off, both ports output */
398     	sound_ym.rd_data_reg_sel = 7;
399     	sound_ym.wd_data = 0xff;
400     }
401     
402     
403     static void atari_call_irq_list( int irq, void *dev_id, struct pt_regs *fp )
404     {
405     	irq_node_t *node;
406     
407     	for (node = (irq_node_t *)dev_id; node; node = node->next)
408     		node->handler(irq, node->dev_id, fp);
409     }
410     
411     
412     /*
413      * atari_request_irq : add an interrupt service routine for a particular
414      *                     machine specific interrupt source.
415      *                     If the addition was successful, it returns 0.
416      */
417     
418     int atari_request_irq(unsigned int irq, void (*handler)(int, void *, struct pt_regs *),
419                           unsigned long flags, const char *devname, void *dev_id)
420     {
421     	int vector;
422     	unsigned long oflags = flags;
423     
424     	/*
425     	 * The following is a hack to make some PCI card drivers work,
426     	 * which set the SA_SHIRQ flag.
427     	 */
428     
429     	flags &= ~SA_SHIRQ;
430     
431     	if (flags == SA_INTERRUPT) {
432     		printk ("%s: SA_INTERRUPT changed to IRQ_TYPE_SLOW for %s\n",
433     			__FUNCTION__, devname);
434     		flags = IRQ_TYPE_SLOW;
435     	}
436     	if (flags < IRQ_TYPE_SLOW || flags > IRQ_TYPE_PRIO) {
437     		printk ("%s: Bad irq type 0x%lx <0x%lx> requested from %s\n",
438     		        __FUNCTION__, flags, oflags, devname);
439     		return -EINVAL;
440     	}
441     	if (!IS_VALID_INTNO(irq)) {
442     		printk ("%s: Unknown irq %d requested from %s\n",
443     		        __FUNCTION__, irq, devname);
444     		return -ENXIO;
445     	}
446     	vector = IRQ_SOURCE_TO_VECTOR(irq);
447     
448     	/*
449     	 * Check type/source combination: slow ints are (currently)
450     	 * only possible for MFP-interrupts.
451     	 */
452     	if (flags == IRQ_TYPE_SLOW &&
453     		(irq < STMFP_SOURCE_BASE || irq >= SCC_SOURCE_BASE)) {
454     		printk ("%s: Slow irq requested for non-MFP source %d from %s\n",
455     		        __FUNCTION__, irq, devname);
456     		return -EINVAL;
457     	}
458     		
459     	if (vectors[vector] == bad_interrupt) {
460     		/* int has no handler yet */
461     		irq_handler[irq].handler = handler;
462     		irq_handler[irq].dev_id  = dev_id;
463     		irq_param[irq].flags   = flags;
464     		irq_param[irq].devname = devname;
465     		vectors[vector] =
466     			(flags == IRQ_TYPE_SLOW) ? slow_handlers[irq-STMFP_SOURCE_BASE] :
467     			(flags == IRQ_TYPE_FAST) ? atari_fast_irq_handler :
468     			                          atari_prio_irq_handler;
469     		/* If MFP int, also enable and umask it */
470     		atari_turnon_irq(irq);
471     		atari_enable_irq(irq);
472     
473     		return 0;
474     	}
475     	else if (irq_param[irq].flags == flags) {
476     		/* old handler is of same type -> handlers can be chained */
477     		irq_node_t *node;
478     		unsigned long flags;
479     
480     		save_flags(flags);
481     		cli();
482     
483     		if (irq_handler[irq].handler != atari_call_irq_list) {
484     			/* Only one handler yet, make a node for this first one */
485     			if (!(node = new_irq_node()))
486     				return -ENOMEM;
487     			node->handler = irq_handler[irq].handler;
488     			node->dev_id  = irq_handler[irq].dev_id;
489     			node->devname = irq_param[irq].devname;
490     			node->next = NULL;
491     
492     			irq_handler[irq].handler = atari_call_irq_list;
493     			irq_handler[irq].dev_id  = node;
494     			irq_param[irq].devname   = "chained";
495     		}
496     
497     		if (!(node = new_irq_node()))
498     			return -ENOMEM;
499     		node->handler = handler;
500     		node->dev_id  = dev_id;
501     		node->devname = devname;
502     		/* new handlers are put in front of the queue */
503     		node->next = irq_handler[irq].dev_id;
504     		irq_handler[irq].dev_id = node;
505     
506     		restore_flags(flags);
507     		return 0;
508     	} else {
509     		printk ("%s: Irq %d allocated by other type int (call from %s)\n",
510     		        __FUNCTION__, irq, devname);
511     		return -EBUSY;
512     	}
513     }
514     
515     void atari_free_irq(unsigned int irq, void *dev_id)
516     {
517     	unsigned long flags;
518     	int vector;
519     	irq_node_t **list, *node;
520     
521     	if (!IS_VALID_INTNO(irq)) {
522     		printk("%s: Unknown irq %d\n", __FUNCTION__, irq);
523     		return;
524     	}
525     
526     	vector = IRQ_SOURCE_TO_VECTOR(irq);
527     	if (vectors[vector] == bad_interrupt)
528     		goto not_found;
529     
530     	save_flags(flags);
531     	cli();
532     
533     	if (irq_handler[irq].handler != atari_call_irq_list) {
534     		/* It's the only handler for the interrupt */
535     		if (irq_handler[irq].dev_id != dev_id) {
536     			restore_flags(flags);
537     			goto not_found;
538     		}
539     		irq_handler[irq].handler = NULL;
540     		irq_handler[irq].dev_id  = NULL;
541     		irq_param[irq].devname   = NULL;
542     		vectors[vector] = bad_interrupt;
543     		/* If MFP int, also disable it */
544     		atari_disable_irq(irq);
545     		atari_turnoff_irq(irq);
546     
547     		restore_flags(flags);
548     		return;
549     	}
550     
551     	/* The interrupt is chained, find the irq on the list */
552     	for(list = (irq_node_t **)&irq_handler[irq].dev_id; *list; list = &(*list)->next) {
553     		if ((*list)->dev_id == dev_id) break;
554     	}
555     	if (!*list) {
556     		restore_flags(flags);
557     		goto not_found;
558     	}
559     
560     	(*list)->handler = NULL; /* Mark it as free for reallocation */
561     	*list = (*list)->next;
562     
563     	/* If there's now only one handler, unchain the interrupt, i.e. plug in
564     	 * the handler directly again and omit atari_call_irq_list */
565     	node = (irq_node_t *)irq_handler[irq].dev_id;
566     	if (node && !node->next) {
567     		irq_handler[irq].handler = node->handler;
568     		irq_handler[irq].dev_id  = node->dev_id;
569     		irq_param[irq].devname   = node->devname;
570     		node->handler = NULL; /* Mark it as free for reallocation */
571     	}
572     
573     	restore_flags(flags);
574     	return;
575     
576     not_found:
577     	printk("%s: tried to remove invalid irq\n", __FUNCTION__);
578     	return;
579     }
580     
581     
582     /*
583      * atari_register_vme_int() returns the number of a free interrupt vector for
584      * hardware with a programmable int vector (probably a VME board).
585      */
586     
587     unsigned long atari_register_vme_int(void)
588     {
589     	int i;
590     
591     	for(i = 0; i < 32; i++)
592     		if((free_vme_vec_bitmap & (1 << i)) == 0)
593     			break;
594     	
595     	if(i == 16)
596     		return 0;
597     
598     	free_vme_vec_bitmap |= 1 << i;
599     	return (VME_SOURCE_BASE + i);
600     }
601     
602     
603     void atari_unregister_vme_int(unsigned long irq)
604     {
605     	if(irq >= VME_SOURCE_BASE && irq < VME_SOURCE_BASE + VME_MAX_SOURCES) {
606     		irq -= VME_SOURCE_BASE;
607     		free_vme_vec_bitmap &= ~(1 << irq);
608     	}
609     }
610     
611     
612     int atari_get_irq_list(char *buf)
613     {
614     	int i, len = 0;
615     
616     	for (i = 0; i < NUM_INT_SOURCES; ++i) {
617     		if (vectors[IRQ_SOURCE_TO_VECTOR(i)] == bad_interrupt)
618     			continue;
619     		if (i < STMFP_SOURCE_BASE)
620     			len += sprintf(buf+len, "auto %2d: %10u ",
621     				       i, kstat.irqs[0][i]);
622     		else
623     			len += sprintf(buf+len, "vec $%02x: %10u ",
624     				       IRQ_SOURCE_TO_VECTOR(i),
625     				       kstat.irqs[0][i]);
626     
627     		if (irq_handler[i].handler != atari_call_irq_list) {
628     			len += sprintf(buf+len, "%s\n", irq_param[i].devname);
629     		}
630     		else {
631     			irq_node_t *p;
632     			for( p = (irq_node_t *)irq_handler[i].dev_id; p; p = p->next ) {
633     				len += sprintf(buf+len, "%s\n", p->devname);
634     				if (p->next)
635     					len += sprintf( buf+len, "                    " );
636     			}
637     		}
638     	}
639     	if (num_spurious)
640     		len += sprintf(buf+len, "spurio.: %10u\n", num_spurious);
641     	
642     	return len;
643     }
644     
645     
646