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  
q40_irq_startup(struct irq_data * data)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  
q40_irq_shutdown(struct irq_data * data)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  
q40_init_IRQ(void)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 jiffy */
110  static int sound_ticks;
111  
112  #define SVOL 45
113  
q40_mksound(unsigned int hz,unsigned int ticks)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  
q40_timer_int(int irq,void * dev_id)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  
q40_sched_init(void)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 */
q40_irq_handler(unsigned int irq,struct pt_regs * fp)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  
q40_irq_enable(struct irq_data * data)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  
q40_irq_disable(struct irq_data * data)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