xref: /illumos-gate/usr/src/uts/i86pc/io/vmm/io/vatpit.c (revision 6960cd89)
1 /*-
2  * Copyright (c) 2018 Joyent, Inc.
3  * Copyright (c) 2014 Tycho Nightingale <tycho.nightingale@pluribusnetworks.com>
4  * Copyright (c) 2011 NetApp, Inc.
5  * All rights reserved.
6  * Copyright (c) 2018 Joyent, Inc.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 #include <sys/param.h>
34 #include <sys/types.h>
35 #include <sys/queue.h>
36 #include <sys/kernel.h>
37 #include <sys/lock.h>
38 #include <sys/malloc.h>
39 #include <sys/mutex.h>
40 #include <sys/systm.h>
41 
42 #include <machine/vmm.h>
43 
44 #include "vmm_ktr.h"
45 #include "vatpic.h"
46 #include "vioapic.h"
47 #include "vatpit.h"
48 
49 static MALLOC_DEFINE(M_VATPIT, "atpit", "bhyve virtual atpit (8254)");
50 
51 #define	VATPIT_LOCK(vatpit)		mtx_lock_spin(&((vatpit)->mtx))
52 #define	VATPIT_UNLOCK(vatpit)		mtx_unlock_spin(&((vatpit)->mtx))
53 #define	VATPIT_LOCKED(vatpit)		mtx_owned(&((vatpit)->mtx))
54 
55 #define	TIMER_SEL_MASK		0xc0
56 #define	TIMER_RW_MASK		0x30
57 #define	TIMER_MODE_MASK		0x0f
58 #define	TIMER_SEL_READBACK	0xc0
59 
60 #define	TIMER_STS_OUT		0x80
61 #define	TIMER_STS_NULLCNT	0x40
62 
63 #define	TIMER_RB_LCTR		0x20
64 #define	TIMER_RB_LSTATUS	0x10
65 #define	TIMER_RB_CTR_2		0x08
66 #define	TIMER_RB_CTR_1		0x04
67 #define	TIMER_RB_CTR_0		0x02
68 
69 #define	TMR2_OUT_STS		0x20
70 
71 #define	PIT_8254_FREQ		1193182
72 #define	TIMER_DIV(freq, hz)	(((freq) + (hz) / 2) / (hz))
73 
74 struct vatpit_callout_arg {
75 	struct vatpit	*vatpit;
76 	int		channel_num;
77 };
78 
79 struct channel {
80 	int		mode;
81 	uint16_t	initial;	/* initial counter value */
82 	struct bintime	now_bt;		/* uptime when counter was loaded */
83 	uint8_t		cr[2];
84 	uint8_t		ol[2];
85 	bool		slatched;	/* status latched */
86 	uint8_t		status;
87 	int		crbyte;
88 	int		olbyte;
89 	int		frbyte;
90 	struct callout	callout;
91 	struct bintime	callout_bt;	/* target time */
92 	struct vatpit_callout_arg callout_arg;
93 };
94 
95 struct vatpit {
96 	struct vm	*vm;
97 	struct mtx	mtx;
98 
99 	struct bintime	freq_bt;
100 
101 	struct channel	channel[3];
102 };
103 
104 static void pit_timer_start_cntr0(struct vatpit *vatpit);
105 
106 static uint64_t
vatpit_delta_ticks(struct vatpit * vatpit,struct channel * c)107 vatpit_delta_ticks(struct vatpit *vatpit, struct channel *c)
108 {
109 	struct bintime delta;
110 	uint64_t result;
111 
112 	binuptime(&delta);
113 	bintime_sub(&delta, &c->now_bt);
114 
115 	result = delta.sec * PIT_8254_FREQ;
116 	result += delta.frac / vatpit->freq_bt.frac;
117 
118 	return (result);
119 }
120 
121 static int
vatpit_get_out(struct vatpit * vatpit,int channel)122 vatpit_get_out(struct vatpit *vatpit, int channel)
123 {
124 	struct channel *c;
125 	uint64_t delta_ticks;
126 	int out;
127 
128 	c = &vatpit->channel[channel];
129 
130 	switch (c->mode) {
131 	case TIMER_INTTC:
132 		delta_ticks = vatpit_delta_ticks(vatpit, c);
133 		out = (delta_ticks >= c->initial);
134 		break;
135 	default:
136 		out = 0;
137 		break;
138 	}
139 
140 	return (out);
141 }
142 
143 static void
vatpit_callout_handler(void * a)144 vatpit_callout_handler(void *a)
145 {
146 	struct vatpit_callout_arg *arg = a;
147 	struct vatpit *vatpit;
148 	struct callout *callout;
149 	struct channel *c;
150 
151 	vatpit = arg->vatpit;
152 	c = &vatpit->channel[arg->channel_num];
153 	callout = &c->callout;
154 
155 	VM_CTR1(vatpit->vm, "atpit t%d fired", arg->channel_num);
156 
157 	VATPIT_LOCK(vatpit);
158 
159 	if (callout_pending(callout))		/* callout was reset */
160 		goto done;
161 
162 	if (!callout_active(callout))		/* callout was stopped */
163 		goto done;
164 
165 	callout_deactivate(callout);
166 
167 	if (c->mode == TIMER_RATEGEN || c->mode == TIMER_SQWAVE) {
168 		pit_timer_start_cntr0(vatpit);
169 	}
170 
171 	vatpic_pulse_irq(vatpit->vm, 0);
172 	vioapic_pulse_irq(vatpit->vm, 2);
173 
174 done:
175 	VATPIT_UNLOCK(vatpit);
176 }
177 
178 static void
pit_timer_start_cntr0(struct vatpit * vatpit)179 pit_timer_start_cntr0(struct vatpit *vatpit)
180 {
181 	struct channel *c;
182 	struct bintime now, delta;
183 	sbintime_t precision;
184 
185 	c = &vatpit->channel[0];
186 	if (c->initial != 0) {
187 		delta.sec = 0;
188 		delta.frac = vatpit->freq_bt.frac * c->initial;
189 		bintime_add(&c->callout_bt, &delta);
190 		precision = bttosbt(delta) >> tc_precexp;
191 
192 		/*
193 		 * Reset 'callout_bt' if the time that the callout
194 		 * was supposed to fire is more than 'c->initial'
195 		 * ticks in the past.
196 		 */
197 		binuptime(&now);
198 		if (BINTIME_CMP(&c->callout_bt, <, &now)) {
199 			c->callout_bt = now;
200 			bintime_add(&c->callout_bt, &delta);
201 		}
202 
203 		callout_reset_sbt(&c->callout, bttosbt(c->callout_bt),
204 		    precision, vatpit_callout_handler, &c->callout_arg,
205 		    C_ABSOLUTE);
206 	}
207 }
208 
209 static uint16_t
pit_update_counter(struct vatpit * vatpit,struct channel * c,bool latch)210 pit_update_counter(struct vatpit *vatpit, struct channel *c, bool latch)
211 {
212 	uint16_t lval;
213 	uint64_t delta_ticks;
214 
215 	/* cannot latch a new value until the old one has been consumed */
216 	if (latch && c->olbyte != 0)
217 		return (0);
218 
219 	if (c->initial == 0) {
220 		/*
221 		 * This is possibly an o/s bug - reading the value of
222 		 * the timer without having set up the initial value.
223 		 *
224 		 * The original user-space version of this code set
225 		 * the timer to 100hz in this condition; do the same
226 		 * here.
227 		 */
228 		c->initial = TIMER_DIV(PIT_8254_FREQ, 100);
229 		binuptime(&c->now_bt);
230 		c->status &= ~TIMER_STS_NULLCNT;
231 	}
232 
233 	delta_ticks = vatpit_delta_ticks(vatpit, c);
234 	lval = c->initial - delta_ticks % c->initial;
235 
236 	if (latch) {
237 		c->olbyte = 2;
238 		c->ol[1] = lval;		/* LSB */
239 		c->ol[0] = lval >> 8;		/* MSB */
240 	}
241 
242 	return (lval);
243 }
244 
245 static int
pit_readback1(struct vatpit * vatpit,int channel,uint8_t cmd)246 pit_readback1(struct vatpit *vatpit, int channel, uint8_t cmd)
247 {
248 	struct channel *c;
249 
250 	c = &vatpit->channel[channel];
251 
252 	/*
253 	 * Latch the count/status of the timer if not already latched.
254 	 * N.B. that the count/status latch-select bits are active-low.
255 	 */
256 	if (!(cmd & TIMER_RB_LCTR) && !c->olbyte) {
257 		(void) pit_update_counter(vatpit, c, true);
258 	}
259 
260 	if (!(cmd & TIMER_RB_LSTATUS) && !c->slatched) {
261 		c->slatched = true;
262 		/*
263 		 * For mode 0, see if the elapsed time is greater
264 		 * than the initial value - this results in the
265 		 * output pin being set to 1 in the status byte.
266 		 */
267 		if (c->mode == TIMER_INTTC && vatpit_get_out(vatpit, channel))
268 			c->status |= TIMER_STS_OUT;
269 		else
270 			c->status &= ~TIMER_STS_OUT;
271 	}
272 
273 	return (0);
274 }
275 
276 static int
pit_readback(struct vatpit * vatpit,uint8_t cmd)277 pit_readback(struct vatpit *vatpit, uint8_t cmd)
278 {
279 	int error;
280 
281 	/*
282 	 * The readback command can apply to all timers.
283 	 */
284 	error = 0;
285 	if (cmd & TIMER_RB_CTR_0)
286 		error = pit_readback1(vatpit, 0, cmd);
287 	if (!error && cmd & TIMER_RB_CTR_1)
288 		error = pit_readback1(vatpit, 1, cmd);
289 	if (!error && cmd & TIMER_RB_CTR_2)
290 		error = pit_readback1(vatpit, 2, cmd);
291 
292 	return (error);
293 }
294 
295 static int
vatpit_update_mode(struct vatpit * vatpit,uint8_t val)296 vatpit_update_mode(struct vatpit *vatpit, uint8_t val)
297 {
298 	struct channel *c;
299 	int sel, rw, mode;
300 
301 	sel = val & TIMER_SEL_MASK;
302 	rw = val & TIMER_RW_MASK;
303 	mode = val & TIMER_MODE_MASK;
304 
305 	if (sel == TIMER_SEL_READBACK)
306 		return (pit_readback(vatpit, val));
307 
308 	if (rw != TIMER_LATCH && rw != TIMER_16BIT)
309 		return (-1);
310 
311 	if (rw != TIMER_LATCH) {
312 		/*
313 		 * Counter mode is not affected when issuing a
314 		 * latch command.
315 		 */
316 		if (mode != TIMER_INTTC &&
317 		    mode != TIMER_RATEGEN &&
318 		    mode != TIMER_SQWAVE &&
319 		    mode != TIMER_SWSTROBE)
320 			return (-1);
321 	}
322 
323 	c = &vatpit->channel[sel >> 6];
324 	if (rw == TIMER_LATCH)
325 		pit_update_counter(vatpit, c, true);
326 	else {
327 		c->mode = mode;
328 		c->olbyte = 0;	/* reset latch after reprogramming */
329 		c->status |= TIMER_STS_NULLCNT;
330 	}
331 
332 	return (0);
333 }
334 
335 int
vatpit_handler(void * arg,bool in,uint16_t port,uint8_t bytes,uint32_t * eax)336 vatpit_handler(void *arg, bool in, uint16_t port, uint8_t bytes, uint32_t *eax)
337 {
338 	struct vatpit *vatpit = arg;
339 	struct channel *c;
340 	uint8_t val;
341 	int error;
342 
343 	if (bytes != 1)
344 		return (-1);
345 
346 	val = *eax;
347 
348 	if (port == TIMER_MODE) {
349 		if (in) {
350 			VM_CTR0(vatpit->vm, "vatpit attempt to read mode");
351 			return (-1);
352 		}
353 
354 		VATPIT_LOCK(vatpit);
355 		error = vatpit_update_mode(vatpit, val);
356 		VATPIT_UNLOCK(vatpit);
357 
358 		return (error);
359 	}
360 
361 	/* counter ports */
362 	KASSERT(port >= TIMER_CNTR0 && port <= TIMER_CNTR2,
363 	    ("invalid port 0x%x", port));
364 	c = &vatpit->channel[port - TIMER_CNTR0];
365 
366 	VATPIT_LOCK(vatpit);
367 	if (in && c->slatched) {
368 		/*
369 		 * Return the status byte if latched
370 		 */
371 		*eax = c->status;
372 		c->slatched = false;
373 		c->status = 0;
374 	} else if (in) {
375 		/*
376 		 * The spec says that once the output latch is completely
377 		 * read it should revert to "following" the counter. Use
378 		 * the free running counter for this case (i.e. Linux
379 		 * TSC calibration). Assuming the access mode is 16-bit,
380 		 * toggle the MSB/LSB bit on each read.
381 		 */
382 		if (c->olbyte == 0) {
383 			uint16_t tmp;
384 
385 			tmp = pit_update_counter(vatpit, c, false);
386 			if (c->frbyte)
387 				tmp >>= 8;
388 			tmp &= 0xff;
389 			*eax = tmp;
390 			c->frbyte ^= 1;
391 		} else {
392 			*eax = c->ol[--c->olbyte];
393 		}
394 	} else {
395 		c->cr[c->crbyte++] = *eax;
396 		if (c->crbyte == 2) {
397 			c->status &= ~TIMER_STS_NULLCNT;
398 			c->frbyte = 0;
399 			c->crbyte = 0;
400 			c->initial = c->cr[0] | (uint16_t)c->cr[1] << 8;
401 			binuptime(&c->now_bt);
402 			/* Start an interval timer for channel 0 */
403 			if (port == TIMER_CNTR0) {
404 				c->callout_bt = c->now_bt;
405 				pit_timer_start_cntr0(vatpit);
406 			}
407 			if (c->initial == 0)
408 				c->initial = 0xffff;
409 		}
410 	}
411 	VATPIT_UNLOCK(vatpit);
412 
413 	return (0);
414 }
415 
416 int
vatpit_nmisc_handler(void * arg,bool in,uint16_t port,uint8_t bytes,uint32_t * eax)417 vatpit_nmisc_handler(void *arg, bool in, uint16_t port, uint8_t bytes,
418     uint32_t *eax)
419 {
420 	struct vatpit *vatpit = arg;
421 
422 	if (in) {
423 			VATPIT_LOCK(vatpit);
424 			if (vatpit_get_out(vatpit, 2))
425 				*eax = TMR2_OUT_STS;
426 			else
427 				*eax = 0;
428 
429 			VATPIT_UNLOCK(vatpit);
430 	}
431 
432 	return (0);
433 }
434 
435 struct vatpit *
vatpit_init(struct vm * vm)436 vatpit_init(struct vm *vm)
437 {
438 	struct vatpit *vatpit;
439 	struct vatpit_callout_arg *arg;
440 	int i;
441 
442 	vatpit = malloc(sizeof (struct vatpit), M_VATPIT, M_WAITOK | M_ZERO);
443 	vatpit->vm = vm;
444 
445 	mtx_init(&vatpit->mtx, "vatpit lock", NULL, MTX_SPIN);
446 
447 	FREQ2BT(PIT_8254_FREQ, &vatpit->freq_bt);
448 
449 	for (i = 0; i < 3; i++) {
450 		callout_init(&vatpit->channel[i].callout, 1);
451 		arg = &vatpit->channel[i].callout_arg;
452 		arg->vatpit = vatpit;
453 		arg->channel_num = i;
454 	}
455 
456 	return (vatpit);
457 }
458 
459 void
vatpit_cleanup(struct vatpit * vatpit)460 vatpit_cleanup(struct vatpit *vatpit)
461 {
462 	int i;
463 
464 	for (i = 0; i < 3; i++)
465 		callout_drain(&vatpit->channel[i].callout);
466 
467 	free(vatpit, M_VATPIT);
468 }
469 
470 #ifndef __FreeBSD__
471 void
vatpit_localize_resources(struct vatpit * vatpit)472 vatpit_localize_resources(struct vatpit *vatpit)
473 {
474 	for (uint_t i = 0; i < 3; i++) {
475 		/* Only localize channels which might be running */
476 		if (vatpit->channel[i].mode != 0) {
477 			vmm_glue_callout_localize(&vatpit->channel[i].callout);
478 		}
479 	}
480 }
481 #endif /* __FreeBSD */
482