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/ptrace.h>
21#include <asm/traps.h>
22
23#include <asm/q40_master.h>
24#include <asm/q40ints.h>
25
26/*
27 * Q40 IRQs are defined as follows:
28 *            3,4,5,6,7,10,11,14,15 : ISA dev IRQs
29 *            16-31: reserved
30 *            32   : keyboard int
31 *            33   : frame int (50/200 Hz periodic timer)
32 *            34   : sample int (10/20 KHz periodic timer)
33 *
34*/
35
36static void q40_irq_handler(unsigned int, struct pt_regs *fp);
37static void q40_irq_enable(struct irq_data *data);
38static void q40_irq_disable(struct irq_data *data);
39
40unsigned short q40_ablecount[35];
41unsigned short q40_state[35];
42
43static unsigned int q40_irq_startup(struct irq_data *data)
44{
45	unsigned int irq = data->irq;
46
47	/* test for ISA ints not implemented by HW */
48	switch (irq) {
49	case 1: case 2: case 8: case 9:
50	case 11: case 12: case 13:
51		printk("%s: ISA IRQ %d not implemented by HW\n", __func__, irq);
52		/* FIXME return -ENXIO; */
53	}
54	return 0;
55}
56
57static void q40_irq_shutdown(struct irq_data *data)
58{
59}
60
61static struct irq_chip q40_irq_chip = {
62	.name		= "q40",
63	.irq_startup	= q40_irq_startup,
64	.irq_shutdown	= q40_irq_shutdown,
65	.irq_enable	= q40_irq_enable,
66	.irq_disable	= q40_irq_disable,
67};
68
69/*
70 * void q40_init_IRQ (void)
71 *
72 * Parameters:	None
73 *
74 * Returns:	Nothing
75 *
76 * This function is called during kernel startup to initialize
77 * the q40 IRQ handling routines.
78 */
79
80static int disabled;
81
82void __init q40_init_IRQ(void)
83{
84	m68k_setup_irq_controller(&q40_irq_chip, handle_simple_irq, 1,
85				  Q40_IRQ_MAX);
86
87	/* setup handler for ISA ints */
88	m68k_setup_auto_interrupt(q40_irq_handler);
89
90	m68k_irq_startup_irq(IRQ_AUTO_2);
91	m68k_irq_startup_irq(IRQ_AUTO_4);
92
93	/* now enable some ints.. */
94	master_outb(1, EXT_ENABLE_REG);  /* ISA IRQ 5-15 */
95
96	/* make sure keyboard IRQ is disabled */
97	master_outb(0, KEY_IRQ_ENABLE_REG);
98}
99
100
101/*
102 * this stuff doesn't really belong here..
103 */
104
105int ql_ticks;              /* 200Hz ticks since last jiffie */
106static int sound_ticks;
107
108#define SVOL 45
109
110void q40_mksound(unsigned int hz, unsigned int ticks)
111{
112	/* for now ignore hz, except that hz==0 switches off sound */
113	/* simply alternate the ampl (128-SVOL)-(128+SVOL)-..-.. at 200Hz */
114	if (hz == 0) {
115		if (sound_ticks)
116			sound_ticks = 1;
117
118		*DAC_LEFT = 128;
119		*DAC_RIGHT = 128;
120
121		return;
122	}
123	/* sound itself is done in q40_timer_int */
124	if (sound_ticks == 0)
125		sound_ticks = 1000; /* pretty long beep */
126	sound_ticks = ticks << 1;
127}
128
129static irq_handler_t q40_timer_routine;
130
131static irqreturn_t q40_timer_int (int irq, void * dev)
132{
133	ql_ticks = ql_ticks ? 0 : 1;
134	if (sound_ticks) {
135		unsigned char sval=(sound_ticks & 1) ? 128-SVOL : 128+SVOL;
136		sound_ticks--;
137		*DAC_LEFT=sval;
138		*DAC_RIGHT=sval;
139	}
140
141	if (!ql_ticks)
142		q40_timer_routine(irq, dev);
143	return IRQ_HANDLED;
144}
145
146void q40_sched_init (irq_handler_t timer_routine)
147{
148	int timer_irq;
149
150	q40_timer_routine = timer_routine;
151	timer_irq = Q40_IRQ_FRAME;
152
153	if (request_irq(timer_irq, q40_timer_int, 0,
154				"timer", q40_timer_int))
155		panic("Couldn't register timer int");
156
157	master_outb(-1, FRAME_CLEAR_REG);
158	master_outb( 1, FRAME_RATE_REG);
159}
160
161
162/*
163 * tables to translate bits into IRQ numbers
164 * it is a good idea to order the entries by priority
165 *
166*/
167
168struct IRQ_TABLE{ unsigned mask; int irq ;};
169#if 0
170static struct IRQ_TABLE iirqs[]={
171  {Q40_IRQ_FRAME_MASK,Q40_IRQ_FRAME},
172  {Q40_IRQ_KEYB_MASK,Q40_IRQ_KEYBOARD},
173  {0,0}};
174#endif
175static struct IRQ_TABLE eirqs[] = {
176  { .mask = Q40_IRQ3_MASK,	.irq = 3 },	/* ser 1 */
177  { .mask = Q40_IRQ4_MASK,	.irq = 4 },	/* ser 2 */
178  { .mask = Q40_IRQ14_MASK,	.irq = 14 },	/* IDE 1 */
179  { .mask = Q40_IRQ15_MASK,	.irq = 15 },	/* IDE 2 */
180  { .mask = Q40_IRQ6_MASK,	.irq = 6 },	/* floppy, handled elsewhere */
181  { .mask = Q40_IRQ7_MASK,	.irq = 7 },	/* par */
182  { .mask = Q40_IRQ5_MASK,	.irq = 5 },
183  { .mask = Q40_IRQ10_MASK,	.irq = 10 },
184  {0,0}
185};
186
187/* complain only this many times about spurious ints : */
188static int ccleirq=60;    /* ISA dev IRQs*/
189/*static int cclirq=60;*/     /* internal */
190
191/* FIXME: add shared ints,mask,unmask,probing.... */
192
193#define IRQ_INPROGRESS 1
194/*static unsigned short saved_mask;*/
195//static int do_tint=0;
196
197#define DEBUG_Q40INT
198/*#define IP_USE_DISABLE *//* would be nice, but crashes ???? */
199
200static int mext_disabled=0;  /* ext irq disabled by master chip? */
201static int aliased_irq=0;  /* how many times inside handler ?*/
202
203
204/* got interrupt, dispatch to ISA or keyboard/timer IRQs */
205static void q40_irq_handler(unsigned int irq, struct pt_regs *fp)
206{
207	unsigned mir, mer;
208	int i;
209
210//repeat:
211	mir = master_inb(IIRQ_REG);
212#ifdef CONFIG_BLK_DEV_FD
213	if ((mir & Q40_IRQ_EXT_MASK) &&
214	    (master_inb(EIRQ_REG) & Q40_IRQ6_MASK)) {
215		floppy_hardint();
216		return;
217	}
218#endif
219	switch (irq) {
220	case 4:
221	case 6:
222		do_IRQ(Q40_IRQ_SAMPLE, fp);
223		return;
224	}
225	if (mir & Q40_IRQ_FRAME_MASK) {
226		do_IRQ(Q40_IRQ_FRAME, fp);
227		master_outb(-1, FRAME_CLEAR_REG);
228	}
229	if ((mir & Q40_IRQ_SER_MASK) || (mir & Q40_IRQ_EXT_MASK)) {
230		mer = master_inb(EIRQ_REG);
231		for (i = 0; eirqs[i].mask; i++) {
232			if (mer & eirqs[i].mask) {
233				irq = eirqs[i].irq;
234/*
235 * There is a little mess wrt which IRQ really caused this irq request. The
236 * main problem is that IIRQ_REG and EIRQ_REG reflect the state when they
237 * are read - which is long after the request came in. In theory IRQs should
238 * not just go away but they occasionally do
239 */
240				if (irq > 4 && irq <= 15 && mext_disabled) {
241					/*aliased_irq++;*/
242					goto iirq;
243				}
244				if (q40_state[irq] & IRQ_INPROGRESS) {
245					/* some handlers do local_irq_enable() for irq latency reasons, */
246					/* however reentering an active irq handler is not permitted */
247#ifdef IP_USE_DISABLE
248					/* in theory this is the better way to do it because it still */
249					/* lets through eg the serial irqs, unfortunately it crashes */
250					disable_irq(irq);
251					disabled = 1;
252#else
253					/*printk("IRQ_INPROGRESS detected for irq %d, disabling - %s disabled\n",
254						irq, disabled ? "already" : "not yet"); */
255					fp->sr = (((fp->sr) & (~0x700))+0x200);
256					disabled = 1;
257#endif
258					goto iirq;
259				}
260				q40_state[irq] |= IRQ_INPROGRESS;
261				do_IRQ(irq, fp);
262				q40_state[irq] &= ~IRQ_INPROGRESS;
263
264				/* naively enable everything, if that fails than    */
265				/* this function will be reentered immediately thus */
266				/* getting another chance to disable the IRQ        */
267
268				if (disabled) {
269#ifdef IP_USE_DISABLE
270					if (irq > 4) {
271						disabled = 0;
272						enable_irq(irq);
273					}
274#else
275					disabled = 0;
276					/*printk("reenabling irq %d\n", irq); */
277#endif
278				}
279// used to do 'goto repeat;' here, this delayed bh processing too long
280				return;
281			}
282		}
283		if (mer && ccleirq > 0 && !aliased_irq) {
284			printk("ISA interrupt from unknown source? EIRQ_REG = %x\n",mer);
285			ccleirq--;
286		}
287	}
288 iirq:
289	mir = master_inb(IIRQ_REG);
290	/* should test whether keyboard irq is really enabled, doing it in defhand */
291	if (mir & Q40_IRQ_KEYB_MASK)
292		do_IRQ(Q40_IRQ_KEYBOARD, fp);
293
294	return;
295}
296
297void q40_irq_enable(struct irq_data *data)
298{
299	unsigned int irq = data->irq;
300
301	if (irq >= 5 && irq <= 15) {
302		mext_disabled--;
303		if (mext_disabled > 0)
304			printk("q40_irq_enable : nested disable/enable\n");
305		if (mext_disabled == 0)
306			master_outb(1, EXT_ENABLE_REG);
307	}
308}
309
310
311void q40_irq_disable(struct irq_data *data)
312{
313	unsigned int irq = data->irq;
314
315	/* disable ISA iqs : only do something if the driver has been
316	 * verified to be Q40 "compatible" - right now IDE, NE2K
317	 * Any driver should not attempt to sleep across disable_irq !!
318	 */
319
320	if (irq >= 5 && irq <= 15) {
321		master_outb(0, EXT_ENABLE_REG);
322		mext_disabled++;
323		if (mext_disabled > 1)
324			printk("disable_irq nesting count %d\n",mext_disabled);
325	}
326}
327