1 /*
2  * Copyright (c) 2006 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
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
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  */
35 
36 #include <sys/types.h>
37 #include <sys/systm.h>
38 #include <sys/kernel.h>
39 #include <sys/systimer.h>
40 #include <sys/sysctl.h>
41 #include <sys/signal.h>
42 #include <sys/interrupt.h>
43 #include <sys/bus.h>
44 #include <sys/time.h>
45 #include <machine/cpu.h>
46 #include <machine/clock.h>
47 #include <machine/globaldata.h>
48 #include <machine/md_var.h>
49 #include <machine/cothread.h>
50 
51 #include <sys/thread2.h>
52 
53 #include <unistd.h>
54 #include <signal.h>
55 #include <time.h>
56 #include <stdio.h>
57 
58 int disable_rtc_set;
59 SYSCTL_INT(_machdep, CPU_DISRTCSET, disable_rtc_set,
60 	   CTLFLAG_RW, &disable_rtc_set, 0, "");
61 SYSCTL_INT(_hw, OID_AUTO, tsc_present, CTLFLAG_RD,
62             &tsc_present, 0, "TSC Available");
63 SYSCTL_INT(_hw, OID_AUTO, tsc_invariant, CTLFLAG_RD,
64             &tsc_invariant, 0, "Invariant TSC");
65 SYSCTL_INT(_hw, OID_AUTO, tsc_mpsync, CTLFLAG_RD,
66             &tsc_mpsync, 0, "TSC is synchronized across CPUs");
67 SYSCTL_QUAD(_hw, OID_AUTO, tsc_frequency, CTLFLAG_RD,
68 	    &tsc_frequency, 0, "TSC Frequency");
69 
70 int adjkerntz;
71 int wall_cmos_clock = 0;
72 SYSCTL_INT(_machdep, CPU_WALLCLOCK, wall_cmos_clock,
73     CTLFLAG_RD, &wall_cmos_clock, 0, "");
74 
75 static cothread_t vktimer_cotd;
76 static int vktimer_running;
77 static sysclock_t vktimer_target;
78 static struct timespec vktimer_ts;
79 static sysclock_t vktimer_reload[MAXCPU];
80 
81 extern int use_precise_timer;
82 
83 /*
84  * SYSTIMER IMPLEMENTATION
85  */
86 static sysclock_t vkernel_timer_get_timecount(void);
87 static void vkernel_timer_construct(struct cputimer *timer, sysclock_t oclock);
88 static void vktimer_thread(cothread_t cotd);
89 
90 static struct cputimer vkernel_cputimer = {
91 	.next		= SLIST_ENTRY_INITIALIZER,
92 	.name		= "VKERNEL",
93 	.pri		= CPUTIMER_PRI_VKERNEL,
94 	.type		= CPUTIMER_VKERNEL,
95 	.count		= vkernel_timer_get_timecount,
96 	.fromhz		= cputimer_default_fromhz,
97 	.fromus		= cputimer_default_fromus,
98 	.construct	= vkernel_timer_construct,
99 	.destruct	= cputimer_default_destruct,
100 	.freq		= 1000000
101 };
102 
103 static void	vktimer_intr_reload(struct cputimer_intr *, sysclock_t);
104 static void	vktimer_intr_initclock(struct cputimer_intr *, boolean_t);
105 
106 static struct cputimer_intr vkernel_cputimer_intr = {
107 	.freq = 1000000,
108 	.reload = vktimer_intr_reload,
109 	.enable = cputimer_intr_default_enable,
110 	.config = cputimer_intr_default_config,
111 	.restart = cputimer_intr_default_restart,
112 	.pmfixup = cputimer_intr_default_pmfixup,
113 	.initclock = vktimer_intr_initclock,
114 	.pcpuhand = NULL,
115 	.next = SLIST_ENTRY_INITIALIZER,
116 	.name = "vkernel",
117 	.type = CPUTIMER_INTR_VKERNEL,
118 	.prio = CPUTIMER_INTR_PRIO_VKERNEL,
119 	.caps = CPUTIMER_INTR_CAP_NONE,
120 	.priv = NULL
121 };
122 
123 /*
124  * Initialize the systimer subsystem, called from MI code in early boot.
125  */
126 static void
127 cpu_initclocks(void *arg __unused)
128 {
129 	kprintf("initclocks\n");
130 	cputimer_intr_register(&vkernel_cputimer_intr);
131 	cputimer_intr_select(&vkernel_cputimer_intr, 0);
132 
133 	cputimer_register(&vkernel_cputimer);
134 	cputimer_select(&vkernel_cputimer, 0);
135 }
136 SYSINIT(clocksvk, SI_BOOT2_CLOCKREG, SI_ORDER_FIRST, cpu_initclocks, NULL);
137 
138 /*
139  * Constructor to initialize timer->base and get an initial count.
140  */
141 static void
142 vkernel_timer_construct(struct cputimer *timer, sysclock_t oclock)
143 {
144 	timer->base = 0;
145 	timer->base = oclock - vkernel_timer_get_timecount();
146 }
147 
148 /*
149  * Get the current counter, with 2's complement rollover.
150  *
151  * NOTE! MPSAFE, possibly no critical section
152  */
153 static sysclock_t
154 vkernel_timer_get_timecount(void)
155 {
156 	struct timespec ts;
157 	sysclock_t count;
158 
159 	if (use_precise_timer)
160 		clock_gettime(CLOCK_MONOTONIC_PRECISE, &ts);
161 	else
162 		clock_gettime(CLOCK_MONOTONIC_FAST, &ts);
163 	count = ts.tv_nsec / 1000;
164 	count += (uint64_t)ts.tv_sec * 1000000;
165 
166 	return count;
167 }
168 
169 /*
170  * Initialize the interrupt for our core systimer.
171  */
172 static void
173 vktimer_intr_initclock(struct cputimer_intr *cti __unused,
174 		       boolean_t selected __unused)
175 {
176 	vktimer_target = sys_cputimer->count();
177 
178 	vktimer_ts.tv_nsec = 1000000000 / 20;
179 	vktimer_cotd = cothread_create(vktimer_thread, NULL, NULL, "vktimer");
180 	while (vktimer_running == 0)
181 		usleep(1000000 / 10);
182 #if 0
183 	KKASSERT(kqueue_timer_info == NULL);
184 	kqueue_timer_info = kqueue_add_timer(vktimer_intr, NULL);
185 #endif
186 }
187 
188 /*
189  *
190  */
191 static void
192 vktimer_sigint(int signo)
193 {
194 	/* do nothing, just interrupt */
195 }
196 
197 static sysclock_t
198 vktimer_gettick_us(void)
199 {
200 	struct clockinfo info;
201 	int mib[] = { CTL_KERN, KERN_CLOCKRATE };
202 	size_t len = sizeof(info);
203 
204 	if (sysctl(mib, NELEM(mib), &info, &len, NULL, 0) != 0 ||
205 	    len != sizeof(info)) {
206 		/* Assume 10 milliseconds (== 100hz) */
207 		return 1000000 / 100;
208 	} else if (info.tick < 999999) {
209 		return info.tick;
210 	} else {
211 		/* Assume 10 milliseconds (== 100hz) */
212 		return 1000000 / 100;
213 	}
214 }
215 
216 static void
217 vktimer_thread(cothread_t cotd)
218 {
219 	struct sigaction sa;
220 	globaldata_t gscan;
221 	sysclock_t ticklength_us;
222 
223 	bzero(&sa, sizeof(sa));
224 	sa.sa_handler = vktimer_sigint;
225 	sa.sa_flags |= SA_NODEFER;
226 	sigemptyset(&sa.sa_mask);
227 	sigaction(SIGINT, &sa, NULL);
228 
229 	ticklength_us = vktimer_gettick_us();
230 	vktimer_running = 1;
231 	while (vktimer_cotd == NULL)
232 		usleep(1000000 / 10);
233 
234 	for (;;) {
235 		sysclock_t curtime;
236 		sysclock_t reload;
237 		ssysclock_t delta;
238 		sysclock_t freq;
239 		int n;
240 
241 		/*
242 		 * Sleep
243 		 */
244 		cothread_sleep(cotd, &vktimer_ts);
245 
246 rescan:
247 		freq = sys_cputimer->freq;
248 		curtime = sys_cputimer->count();
249 		reload = freq - 1;
250 
251 		/*
252 		 * Reset the target
253 		 */
254 		for (n = 0; n < ncpus; ++n) {
255 			gscan = globaldata_find(n);
256 			delta = vktimer_reload[n] - curtime;
257 			if (delta <= 0 && TAILQ_FIRST(&gscan->gd_systimerq))
258 				pthread_kill(ap_tids[n], SIGURG);
259 			if (delta > 0 && reload > delta)
260 				reload = delta;
261 		}
262 		reload += curtime;
263 		vktimer_target = reload;
264 
265 		/*
266 		 * Check for races
267 		 */
268 		reload -= curtime;
269 		for (n = 0; n < ncpus; ++n) {
270 			gscan = globaldata_find(n);
271 			delta = vktimer_reload[n] - curtime;
272 			if (delta > 0 && reload > delta)
273 				goto rescan;
274 		}
275 		if (sys_cputimer == &vkernel_cputimer &&
276                     !use_precise_timer && reload < ticklength_us / 10) {
277 			/*
278 			 * Avoid pointless short sleeps, when we only measure
279 			 * the current time at tick precision.
280 			 */
281 			reload = ticklength_us / 10;
282 		}
283 		vktimer_ts.tv_nsec = muldivu64(reload, 1000000000, freq);
284 	}
285 }
286 
287 /*
288  * Reload the interrupt for our core systimer.  Because the caller's
289  * reload calculation can be negatively indexed, we need a minimal
290  * check to ensure that a reasonable reload value is selected.
291  */
292 static void
293 vktimer_intr_reload(struct cputimer_intr *cti __unused, sysclock_t reload)
294 {
295 	if ((ssysclock_t)reload < 0)		/* neg value */
296 		reload = 1;
297 	if (reload >= sys_cputimer->freq)	/* max one second */
298 		reload = sys_cputimer->freq;
299 	reload += sys_cputimer->count();
300 	vktimer_reload[mycpu->gd_cpuid] = reload;
301 	if (vktimer_cotd && (ssysclock_t)(reload - vktimer_target) < 0) {
302 		while ((sysclock_t)(reload - vktimer_target) < 0)
303 			reload = atomic_swap_long(&vktimer_target, reload);
304 		cothread_wakeup(vktimer_cotd, &vktimer_ts);
305 	}
306 }
307 
308 /*
309  * pcpu clock interrupt (hard interrupt)
310  */
311 void
312 vktimer_intr(struct intrframe *frame)
313 {
314 	struct globaldata *gd = mycpu;
315 	sysclock_t sysclock_count;
316 
317 	sysclock_count = sys_cputimer->count();
318 	++gd->gd_cnt.v_timer;
319 	systimer_intr(&sysclock_count, 0, frame);
320 }
321 
322 /*
323  * Initialize the time of day register, based on the time base which is, e.g.
324  * from a filesystem.
325  */
326 void
327 inittodr(time_t base)
328 {
329 	struct timespec ts;
330 	struct timeval tv;
331 
332 	gettimeofday(&tv, NULL);
333 	ts.tv_sec = tv.tv_sec;
334 	ts.tv_nsec = tv.tv_usec * 1000;
335 	set_timeofday(&ts);
336 }
337 
338 /*
339  * Write system time back to the RTC
340  */
341 void
342 resettodr(void)
343 {
344 }
345 
346 /*
347  * We need to enter a critical section to prevent signals from recursing
348  * into pthreads.
349  */
350 void
351 DELAY(int usec)
352 {
353 	crit_enter();
354 	usleep(usec);
355 	crit_exit();
356 }
357 
358 void
359 DRIVERSLEEP(int usec)
360 {
361         if (mycpu->gd_intr_nesting_level)
362 		DELAY(usec);
363 	else if (1000000 / usec >= hz)
364 		tsleep(DRIVERSLEEP, 0, "DELAY", 1000000 / usec / hz + 1);
365 	else
366 		DELAY(usec);
367 }
368