q40ints.c

  1/*
  2 * arch/m68k/q40/q40ints.c
  3 *
  4 * Copyright (C) 1999,2001 Richard Zidlicky
  5 *
  6 * This file is subject to the terms and conditions of the GNU General Public
  7 * License.  See the file COPYING in the main directory of this archive
  8 * for more details.
  9 *
 10 * .. used to be loosely based on bvme6000ints.c
 11 *
 12 */
 13
 14#include <linux/types.h>
 15#include <linux/kernel.h>
 16#include <linux/errno.h>
 17#include <linux/interrupt.h>
 18#include <linux/irq.h>
 19
 20#include <asm/machdep.h>
 21#include <asm/ptrace.h>
 22#include <asm/traps.h>
 23
 24#include <asm/q40_master.h>
 25#include <asm/q40ints.h>
 26
 27#include "q40.h"
 28
 29/*
 30 * Q40 IRQs are defined as follows:
 31 *            3,4,5,6,7,10,11,14,15 : ISA dev IRQs
 32 *            16-31: reserved
 33 *            32   : keyboard int
 34 *            33   : frame int (50/200 Hz periodic timer)
 35 *            34   : sample int (10/20 KHz periodic timer)
 36 *
 37 */
 38
 39static void q40_irq_handler(unsigned int, struct pt_regs *fp);
 40static void q40_irq_enable(struct irq_data *data);
 41static void q40_irq_disable(struct irq_data *data);
 42
 43unsigned short q40_ablecount[35];
 44unsigned short q40_state[35];
 45
 46static unsigned int q40_irq_startup(struct irq_data *data)
 47{
 48	unsigned int irq = data->irq;
 49
 50	/* test for ISA ints not implemented by HW */
 51	switch (irq) {
 52	case 1: case 2: case 8: case 9:
 53	case 11: case 12: case 13:
 54		pr_warn("%s: ISA IRQ %d not implemented by HW\n", __func__,
 55			irq);
 56		/* FIXME return -ENXIO; */
 57	}
 58	return 0;
 59}
 60
 61static void q40_irq_shutdown(struct irq_data *data)
 62{
 63}
 64
 65static struct irq_chip q40_irq_chip = {
 66	.name		= "q40",
 67	.irq_startup	= q40_irq_startup,
 68	.irq_shutdown	= q40_irq_shutdown,
 69	.irq_enable	= q40_irq_enable,
 70	.irq_disable	= q40_irq_disable,
 71};
 72
 73/*
 74 * void q40_init_IRQ (void)
 75 *
 76 * Parameters:	None
 77 *
 78 * Returns:	Nothing
 79 *
 80 * This function is called during kernel startup to initialize
 81 * the q40 IRQ handling routines.
 82 */
 83
 84static int disabled;
 85
 86void __init q40_init_IRQ(void)
 87{
 88	m68k_setup_irq_controller(&q40_irq_chip, handle_simple_irq, 1,
 89				  Q40_IRQ_MAX);
 90
 91	/* setup handler for ISA ints */
 92	m68k_setup_auto_interrupt(q40_irq_handler);
 93
 94	m68k_irq_startup_irq(IRQ_AUTO_2);
 95	m68k_irq_startup_irq(IRQ_AUTO_4);
 96
 97	/* now enable some ints.. */
 98	master_outb(1, EXT_ENABLE_REG);  /* ISA IRQ 5-15 */
 99
100	/* make sure keyboard IRQ is disabled */
101	master_outb(0, KEY_IRQ_ENABLE_REG);
102}
103
104
105/*
106 * this stuff doesn't really belong here..
107 */
108
109int ql_ticks;              /* 200Hz ticks since last jiffy */
110static int sound_ticks;
111
112#define SVOL 45
113
114void q40_mksound(unsigned int hz, unsigned int ticks)
115{
116	/* for now ignore hz, except that hz==0 switches off sound */
117	/* simply alternate the ampl (128-SVOL)-(128+SVOL)-..-.. at 200Hz */
118	if (hz == 0) {
119		if (sound_ticks)
120			sound_ticks = 1;
121
122		*DAC_LEFT = 128;
123		*DAC_RIGHT = 128;
124
125		return;
126	}
127	/* sound itself is done in q40_timer_int */
128	if (sound_ticks == 0)
129		sound_ticks = 1000; /* pretty long beep */
130	sound_ticks = ticks << 1;
131}
132
133static irqreturn_t q40_timer_int(int irq, void *dev_id)
134{
135	ql_ticks = ql_ticks ? 0 : 1;
136	if (sound_ticks) {
137		unsigned char sval=(sound_ticks & 1) ? 128-SVOL : 128+SVOL;
138		sound_ticks--;
139		*DAC_LEFT=sval;
140		*DAC_RIGHT=sval;
141	}
142
143	if (!ql_ticks) {
144		unsigned long flags;
145
146		local_irq_save(flags);
147		legacy_timer_tick(1);
148		timer_heartbeat();
149		local_irq_restore(flags);
150	}
151	return IRQ_HANDLED;
152}
153
154void q40_sched_init (void)
155{
156	int timer_irq;
157
158	timer_irq = Q40_IRQ_FRAME;
159
160	if (request_irq(timer_irq, q40_timer_int, 0, "timer", NULL))
161		panic("Couldn't register timer int");
162
163	master_outb(-1, FRAME_CLEAR_REG);
164	master_outb( 1, FRAME_RATE_REG);
165}
166
167
168/*
169 * tables to translate bits into IRQ numbers
170 * it is a good idea to order the entries by priority
171 *
172*/
173
174struct IRQ_TABLE{ unsigned mask; int irq ;};
175#if 0
176static struct IRQ_TABLE iirqs[]={
177  {Q40_IRQ_FRAME_MASK,Q40_IRQ_FRAME},
178  {Q40_IRQ_KEYB_MASK,Q40_IRQ_KEYBOARD},
179  {0,0}};
180#endif
181static struct IRQ_TABLE eirqs[] = {
182  { .mask = Q40_IRQ3_MASK,	.irq = 3 },	/* ser 1 */
183  { .mask = Q40_IRQ4_MASK,	.irq = 4 },	/* ser 2 */
184  { .mask = Q40_IRQ14_MASK,	.irq = 14 },	/* IDE 1 */
185  { .mask = Q40_IRQ15_MASK,	.irq = 15 },	/* IDE 2 */
186  { .mask = Q40_IRQ6_MASK,	.irq = 6 },	/* floppy, handled elsewhere */
187  { .mask = Q40_IRQ7_MASK,	.irq = 7 },	/* par */
188  { .mask = Q40_IRQ5_MASK,	.irq = 5 },
189  { .mask = Q40_IRQ10_MASK,	.irq = 10 },
190  {0,0}
191};
192
193/* complain only this many times about spurious ints : */
194static int ccleirq=60;    /* ISA dev IRQs*/
195/*static int cclirq=60;*/     /* internal */
196
197/* FIXME: add shared ints,mask,unmask,probing.... */
198
199#define IRQ_INPROGRESS 1
200/*static unsigned short saved_mask;*/
201//static int do_tint=0;
202
203#define DEBUG_Q40INT
204/*#define IP_USE_DISABLE *//* would be nice, but crashes ???? */
205
206static int mext_disabled;	/* ext irq disabled by master chip? */
207static int aliased_irq;		/* how many times inside handler ?*/
208
209
210/* got interrupt, dispatch to ISA or keyboard/timer IRQs */
211static void q40_irq_handler(unsigned int irq, struct pt_regs *fp)
212{
213	unsigned mir, mer;
214	int i;
215
216//repeat:
217	mir = master_inb(IIRQ_REG);
218#ifdef CONFIG_BLK_DEV_FD
219	if ((mir & Q40_IRQ_EXT_MASK) &&
220	    (master_inb(EIRQ_REG) & Q40_IRQ6_MASK)) {
221		floppy_hardint();
222		return;
223	}
224#endif
225	switch (irq) {
226	case 4:
227	case 6:
228		do_IRQ(Q40_IRQ_SAMPLE, fp);
229		return;
230	}
231	if (mir & Q40_IRQ_FRAME_MASK) {
232		do_IRQ(Q40_IRQ_FRAME, fp);
233		master_outb(-1, FRAME_CLEAR_REG);
234	}
235	if ((mir & Q40_IRQ_SER_MASK) || (mir & Q40_IRQ_EXT_MASK)) {
236		mer = master_inb(EIRQ_REG);
237		for (i = 0; eirqs[i].mask; i++) {
238			if (mer & eirqs[i].mask) {
239				irq = eirqs[i].irq;
240/*
241 * There is a little mess wrt which IRQ really caused this irq request. The
242 * main problem is that IIRQ_REG and EIRQ_REG reflect the state when they
243 * are read - which is long after the request came in. In theory IRQs should
244 * not just go away but they occasionally do
245 */
246				if (irq > 4 && irq <= 15 && mext_disabled) {
247					/*aliased_irq++;*/
248					goto iirq;
249				}
250				if (q40_state[irq] & IRQ_INPROGRESS) {
251					/* some handlers do local_irq_enable() for irq latency reasons, */
252					/* however reentering an active irq handler is not permitted */
253#ifdef IP_USE_DISABLE
254					/* in theory this is the better way to do it because it still */
255					/* lets through eg the serial irqs, unfortunately it crashes */
256					disable_irq(irq);
257					disabled = 1;
258#else
259					/*pr_warn("IRQ_INPROGRESS detected for irq %d, disabling - %s disabled\n",
260						irq, disabled ? "already" : "not yet"); */
261					fp->sr = (((fp->sr) & (~0x700))+0x200);
262					disabled = 1;
263#endif
264					goto iirq;
265				}
266				q40_state[irq] |= IRQ_INPROGRESS;
267				do_IRQ(irq, fp);
268				q40_state[irq] &= ~IRQ_INPROGRESS;
269
270				/* naively enable everything, if that fails than    */
271				/* this function will be reentered immediately thus */
272				/* getting another chance to disable the IRQ        */
273
274				if (disabled) {
275#ifdef IP_USE_DISABLE
276					if (irq > 4) {
277						disabled = 0;
278						enable_irq(irq);
279					}
280#else
281					disabled = 0;
282					/*pr_info("reenabling irq %d\n", irq); */
283#endif
284				}
285// used to do 'goto repeat;' here, this delayed bh processing too long
286				return;
287			}
288		}
289		if (mer && ccleirq > 0 && !aliased_irq) {
290			pr_warn("ISA interrupt from unknown source? EIRQ_REG = %x\n",
291				mer);
292			ccleirq--;
293		}
294	}
295 iirq:
296	mir = master_inb(IIRQ_REG);
297	/* should test whether keyboard irq is really enabled, doing it in defhand */
298	if (mir & Q40_IRQ_KEYB_MASK)
299		do_IRQ(Q40_IRQ_KEYBOARD, fp);
300
301	return;
302}
303
304void q40_irq_enable(struct irq_data *data)
305{
306	unsigned int irq = data->irq;
307
308	if (irq >= 5 && irq <= 15) {
309		mext_disabled--;
310		if (mext_disabled > 0)
311			pr_warn("q40_irq_enable : nested disable/enable\n");
312		if (mext_disabled == 0)
313			master_outb(1, EXT_ENABLE_REG);
314	}
315}
316
317
318void q40_irq_disable(struct irq_data *data)
319{
320	unsigned int irq = data->irq;
321
322	/* disable ISA iqs : only do something if the driver has been
323	 * verified to be Q40 "compatible" - right now IDE, NE2K
324	 * Any driver should not attempt to sleep across disable_irq !!
325	 */
326
327	if (irq >= 5 && irq <= 15) {
328		master_outb(0, EXT_ENABLE_REG);
329		mext_disabled++;
330		if (mext_disabled > 1)
331			pr_info("disable_irq nesting count %d\n",
332				mext_disabled);
333	}
334}