xref: /linux/arch/m68k/q40/q40ints.c (revision e7d759f31ca295d589f7420719c311870bb3166f)
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 
39 static void q40_irq_handler(unsigned int, struct pt_regs *fp);
40 static void q40_irq_enable(struct irq_data *data);
41 static void q40_irq_disable(struct irq_data *data);
42 
43 unsigned short q40_ablecount[35];
44 unsigned short q40_state[35];
45 
46 static 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 
61 static void q40_irq_shutdown(struct irq_data *data)
62 {
63 }
64 
65 static 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 
84 static int disabled;
85 
86 void __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 
109 int ql_ticks;              /* 200Hz ticks since last jiffie */
110 static int sound_ticks;
111 
112 #define SVOL 45
113 
114 void 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 
133 static 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 
154 void 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 
174 struct IRQ_TABLE{ unsigned mask; int irq ;};
175 #if 0
176 static 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
181 static 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 : */
194 static 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 
206 static int mext_disabled;	/* ext irq disabled by master chip? */
207 static int aliased_irq;		/* how many times inside handler ?*/
208 
209 
210 /* got interrupt, dispatch to ISA or keyboard/timer IRQs */
211 static 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 
304 void 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 
318 void 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 }
335