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