xref: /openbmc/linux/arch/m68k/q40/q40ints.c (revision 40202cca)
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 /*
28  * Q40 IRQs are defined as follows:
29  *            3,4,5,6,7,10,11,14,15 : ISA dev IRQs
30  *            16-31: reserved
31  *            32   : keyboard int
32  *            33   : frame int (50/200 Hz periodic timer)
33  *            34   : sample int (10/20 KHz periodic timer)
34  *
35  */
36 
37 static void q40_irq_handler(unsigned int, struct pt_regs *fp);
38 static void q40_irq_enable(struct irq_data *data);
39 static void q40_irq_disable(struct irq_data *data);
40 
41 unsigned short q40_ablecount[35];
42 unsigned short q40_state[35];
43 
q40_irq_startup(struct irq_data * data)44 static unsigned int q40_irq_startup(struct irq_data *data)
45 {
46 	unsigned int irq = data->irq;
47 
48 	/* test for ISA ints not implemented by HW */
49 	switch (irq) {
50 	case 1: case 2: case 8: case 9:
51 	case 11: case 12: case 13:
52 		pr_warn("%s: ISA IRQ %d not implemented by HW\n", __func__,
53 			irq);
54 		/* FIXME return -ENXIO; */
55 	}
56 	return 0;
57 }
58 
q40_irq_shutdown(struct irq_data * data)59 static void q40_irq_shutdown(struct irq_data *data)
60 {
61 }
62 
63 static struct irq_chip q40_irq_chip = {
64 	.name		= "q40",
65 	.irq_startup	= q40_irq_startup,
66 	.irq_shutdown	= q40_irq_shutdown,
67 	.irq_enable	= q40_irq_enable,
68 	.irq_disable	= q40_irq_disable,
69 };
70 
71 /*
72  * void q40_init_IRQ (void)
73  *
74  * Parameters:	None
75  *
76  * Returns:	Nothing
77  *
78  * This function is called during kernel startup to initialize
79  * the q40 IRQ handling routines.
80  */
81 
82 static int disabled;
83 
q40_init_IRQ(void)84 void __init q40_init_IRQ(void)
85 {
86 	m68k_setup_irq_controller(&q40_irq_chip, handle_simple_irq, 1,
87 				  Q40_IRQ_MAX);
88 
89 	/* setup handler for ISA ints */
90 	m68k_setup_auto_interrupt(q40_irq_handler);
91 
92 	m68k_irq_startup_irq(IRQ_AUTO_2);
93 	m68k_irq_startup_irq(IRQ_AUTO_4);
94 
95 	/* now enable some ints.. */
96 	master_outb(1, EXT_ENABLE_REG);  /* ISA IRQ 5-15 */
97 
98 	/* make sure keyboard IRQ is disabled */
99 	master_outb(0, KEY_IRQ_ENABLE_REG);
100 }
101 
102 
103 /*
104  * this stuff doesn't really belong here..
105  */
106 
107 int ql_ticks;              /* 200Hz ticks since last jiffie */
108 static int sound_ticks;
109 
110 #define SVOL 45
111 
q40_mksound(unsigned int hz,unsigned int ticks)112 void q40_mksound(unsigned int hz, unsigned int ticks)
113 {
114 	/* for now ignore hz, except that hz==0 switches off sound */
115 	/* simply alternate the ampl (128-SVOL)-(128+SVOL)-..-.. at 200Hz */
116 	if (hz == 0) {
117 		if (sound_ticks)
118 			sound_ticks = 1;
119 
120 		*DAC_LEFT = 128;
121 		*DAC_RIGHT = 128;
122 
123 		return;
124 	}
125 	/* sound itself is done in q40_timer_int */
126 	if (sound_ticks == 0)
127 		sound_ticks = 1000; /* pretty long beep */
128 	sound_ticks = ticks << 1;
129 }
130 
q40_timer_int(int irq,void * dev_id)131 static irqreturn_t q40_timer_int(int irq, void *dev_id)
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 		unsigned long flags;
143 
144 		local_irq_save(flags);
145 		legacy_timer_tick(1);
146 		timer_heartbeat();
147 		local_irq_restore(flags);
148 	}
149 	return IRQ_HANDLED;
150 }
151 
q40_sched_init(void)152 void q40_sched_init (void)
153 {
154 	int timer_irq;
155 
156 	timer_irq = Q40_IRQ_FRAME;
157 
158 	if (request_irq(timer_irq, q40_timer_int, 0, "timer", NULL))
159 		panic("Couldn't register timer int");
160 
161 	master_outb(-1, FRAME_CLEAR_REG);
162 	master_outb( 1, FRAME_RATE_REG);
163 }
164 
165 
166 /*
167  * tables to translate bits into IRQ numbers
168  * it is a good idea to order the entries by priority
169  *
170 */
171 
172 struct IRQ_TABLE{ unsigned mask; int irq ;};
173 #if 0
174 static struct IRQ_TABLE iirqs[]={
175   {Q40_IRQ_FRAME_MASK,Q40_IRQ_FRAME},
176   {Q40_IRQ_KEYB_MASK,Q40_IRQ_KEYBOARD},
177   {0,0}};
178 #endif
179 static struct IRQ_TABLE eirqs[] = {
180   { .mask = Q40_IRQ3_MASK,	.irq = 3 },	/* ser 1 */
181   { .mask = Q40_IRQ4_MASK,	.irq = 4 },	/* ser 2 */
182   { .mask = Q40_IRQ14_MASK,	.irq = 14 },	/* IDE 1 */
183   { .mask = Q40_IRQ15_MASK,	.irq = 15 },	/* IDE 2 */
184   { .mask = Q40_IRQ6_MASK,	.irq = 6 },	/* floppy, handled elsewhere */
185   { .mask = Q40_IRQ7_MASK,	.irq = 7 },	/* par */
186   { .mask = Q40_IRQ5_MASK,	.irq = 5 },
187   { .mask = Q40_IRQ10_MASK,	.irq = 10 },
188   {0,0}
189 };
190 
191 /* complain only this many times about spurious ints : */
192 static int ccleirq=60;    /* ISA dev IRQs*/
193 /*static int cclirq=60;*/     /* internal */
194 
195 /* FIXME: add shared ints,mask,unmask,probing.... */
196 
197 #define IRQ_INPROGRESS 1
198 /*static unsigned short saved_mask;*/
199 //static int do_tint=0;
200 
201 #define DEBUG_Q40INT
202 /*#define IP_USE_DISABLE *//* would be nice, but crashes ???? */
203 
204 static int mext_disabled;	/* ext irq disabled by master chip? */
205 static int aliased_irq;		/* how many times inside handler ?*/
206 
207 
208 /* got interrupt, dispatch to ISA or keyboard/timer IRQs */
q40_irq_handler(unsigned int irq,struct pt_regs * fp)209 static void q40_irq_handler(unsigned int irq, struct pt_regs *fp)
210 {
211 	unsigned mir, mer;
212 	int i;
213 
214 //repeat:
215 	mir = master_inb(IIRQ_REG);
216 #ifdef CONFIG_BLK_DEV_FD
217 	if ((mir & Q40_IRQ_EXT_MASK) &&
218 	    (master_inb(EIRQ_REG) & Q40_IRQ6_MASK)) {
219 		floppy_hardint();
220 		return;
221 	}
222 #endif
223 	switch (irq) {
224 	case 4:
225 	case 6:
226 		do_IRQ(Q40_IRQ_SAMPLE, fp);
227 		return;
228 	}
229 	if (mir & Q40_IRQ_FRAME_MASK) {
230 		do_IRQ(Q40_IRQ_FRAME, fp);
231 		master_outb(-1, FRAME_CLEAR_REG);
232 	}
233 	if ((mir & Q40_IRQ_SER_MASK) || (mir & Q40_IRQ_EXT_MASK)) {
234 		mer = master_inb(EIRQ_REG);
235 		for (i = 0; eirqs[i].mask; i++) {
236 			if (mer & eirqs[i].mask) {
237 				irq = eirqs[i].irq;
238 /*
239  * There is a little mess wrt which IRQ really caused this irq request. The
240  * main problem is that IIRQ_REG and EIRQ_REG reflect the state when they
241  * are read - which is long after the request came in. In theory IRQs should
242  * not just go away but they occasionally do
243  */
244 				if (irq > 4 && irq <= 15 && mext_disabled) {
245 					/*aliased_irq++;*/
246 					goto iirq;
247 				}
248 				if (q40_state[irq] & IRQ_INPROGRESS) {
249 					/* some handlers do local_irq_enable() for irq latency reasons, */
250 					/* however reentering an active irq handler is not permitted */
251 #ifdef IP_USE_DISABLE
252 					/* in theory this is the better way to do it because it still */
253 					/* lets through eg the serial irqs, unfortunately it crashes */
254 					disable_irq(irq);
255 					disabled = 1;
256 #else
257 					/*pr_warn("IRQ_INPROGRESS detected for irq %d, disabling - %s disabled\n",
258 						irq, disabled ? "already" : "not yet"); */
259 					fp->sr = (((fp->sr) & (~0x700))+0x200);
260 					disabled = 1;
261 #endif
262 					goto iirq;
263 				}
264 				q40_state[irq] |= IRQ_INPROGRESS;
265 				do_IRQ(irq, fp);
266 				q40_state[irq] &= ~IRQ_INPROGRESS;
267 
268 				/* naively enable everything, if that fails than    */
269 				/* this function will be reentered immediately thus */
270 				/* getting another chance to disable the IRQ        */
271 
272 				if (disabled) {
273 #ifdef IP_USE_DISABLE
274 					if (irq > 4) {
275 						disabled = 0;
276 						enable_irq(irq);
277 					}
278 #else
279 					disabled = 0;
280 					/*pr_info("reenabling irq %d\n", irq); */
281 #endif
282 				}
283 // used to do 'goto repeat;' here, this delayed bh processing too long
284 				return;
285 			}
286 		}
287 		if (mer && ccleirq > 0 && !aliased_irq) {
288 			pr_warn("ISA interrupt from unknown source? EIRQ_REG = %x\n",
289 				mer);
290 			ccleirq--;
291 		}
292 	}
293  iirq:
294 	mir = master_inb(IIRQ_REG);
295 	/* should test whether keyboard irq is really enabled, doing it in defhand */
296 	if (mir & Q40_IRQ_KEYB_MASK)
297 		do_IRQ(Q40_IRQ_KEYBOARD, fp);
298 
299 	return;
300 }
301 
q40_irq_enable(struct irq_data * data)302 void q40_irq_enable(struct irq_data *data)
303 {
304 	unsigned int irq = data->irq;
305 
306 	if (irq >= 5 && irq <= 15) {
307 		mext_disabled--;
308 		if (mext_disabled > 0)
309 			pr_warn("q40_irq_enable : nested disable/enable\n");
310 		if (mext_disabled == 0)
311 			master_outb(1, EXT_ENABLE_REG);
312 	}
313 }
314 
315 
q40_irq_disable(struct irq_data * data)316 void q40_irq_disable(struct irq_data *data)
317 {
318 	unsigned int irq = data->irq;
319 
320 	/* disable ISA iqs : only do something if the driver has been
321 	 * verified to be Q40 "compatible" - right now IDE, NE2K
322 	 * Any driver should not attempt to sleep across disable_irq !!
323 	 */
324 
325 	if (irq >= 5 && irq <= 15) {
326 		master_outb(0, EXT_ENABLE_REG);
327 		mext_disabled++;
328 		if (mext_disabled > 1)
329 			pr_info("disable_irq nesting count %d\n",
330 				mext_disabled);
331 	}
332 }
333