1/*-
2 * Copyright (c) 2000, 2001 Michael Smith
3 * Copyright (c) 2000 BSDi
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 THE AUTHOR AND CONTRIBUTORS ``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 THE AUTHOR 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 "opt_acpi.h"
32#include <sys/param.h>
33#include <sys/bus.h>
34#include <sys/eventhandler.h>
35#include <sys/kernel.h>
36#include <sys/module.h>
37#include <sys/sysctl.h>
38#include <sys/timetc.h>
39
40#include <machine/bus.h>
41#include <machine/resource.h>
42#include <sys/rman.h>
43
44#include <contrib/dev/acpica/include/acpi.h>
45#include <contrib/dev/acpica/include/accommon.h>
46
47#include <dev/acpica/acpivar.h>
48#include <dev/pci/pcivar.h>
49
50/*
51 * A timecounter based on the free-running ACPI timer.
52 *
53 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
54 */
55
56/* Hooks for the ACPI CA debugging infrastructure */
57#define _COMPONENT	ACPI_TIMER
58ACPI_MODULE_NAME("TIMER")
59
60static device_t			acpi_timer_dev;
61static struct resource		*acpi_timer_reg;
62static bus_space_handle_t	acpi_timer_bsh;
63static bus_space_tag_t		acpi_timer_bst;
64static eventhandler_tag		acpi_timer_eh;
65
66static u_int	acpi_timer_frequency = 14318182 / 4;
67
68/* Knob to disable acpi_timer device */
69bool acpi_timer_disabled = false;
70
71static void	acpi_timer_identify(driver_t *driver, device_t parent);
72static int	acpi_timer_probe(device_t dev);
73static int	acpi_timer_attach(device_t dev);
74static void	acpi_timer_resume_handler(struct timecounter *);
75static void	acpi_timer_suspend_handler(struct timecounter *);
76static u_int	acpi_timer_get_timecount(struct timecounter *tc);
77static u_int	acpi_timer_get_timecount_safe(struct timecounter *tc);
78static int	acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
79static void	acpi_timer_boot_test(void);
80
81static int	acpi_timer_test(void);
82
83static device_method_t acpi_timer_methods[] = {
84    DEVMETHOD(device_identify,	acpi_timer_identify),
85    DEVMETHOD(device_probe,	acpi_timer_probe),
86    DEVMETHOD(device_attach,	acpi_timer_attach),
87
88    DEVMETHOD_END
89};
90
91static driver_t acpi_timer_driver = {
92    "acpi_timer",
93    acpi_timer_methods,
94    0,
95};
96
97static devclass_t acpi_timer_devclass;
98DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
99MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1);
100
101static struct timecounter acpi_timer_timecounter = {
102	acpi_timer_get_timecount_safe,	/* get_timecount function */
103	0,				/* no poll_pps */
104	0,				/* no default counter_mask */
105	0,				/* no default frequency */
106	"ACPI",				/* name */
107	-1				/* quality (chosen later) */
108};
109
110static __inline uint32_t
111acpi_timer_read(void)
112{
113
114    return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0));
115}
116
117/*
118 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
119 * we will be using.
120 */
121static void
122acpi_timer_identify(driver_t *driver, device_t parent)
123{
124    device_t dev;
125    rman_res_t rlen, rstart;
126    int rid, rtype;
127
128    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
129
130    if (acpi_disabled("timer") || (acpi_quirks & ACPI_Q_TIMER) ||
131	acpi_timer_dev || acpi_timer_disabled ||
132	AcpiGbl_FADT.PmTimerLength == 0)
133	return_VOID;
134
135    if ((dev = BUS_ADD_CHILD(parent, 2, "acpi_timer", 0)) == NULL) {
136	device_printf(parent, "could not add acpi_timer0\n");
137	return_VOID;
138    }
139    acpi_timer_dev = dev;
140
141    switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
142    case ACPI_ADR_SPACE_SYSTEM_MEMORY:
143	rtype = SYS_RES_MEMORY;
144	break;
145    case ACPI_ADR_SPACE_SYSTEM_IO:
146	rtype = SYS_RES_IOPORT;
147	break;
148    default:
149	return_VOID;
150    }
151    rid = 0;
152    rlen = AcpiGbl_FADT.PmTimerLength;
153    rstart = AcpiGbl_FADT.XPmTimerBlock.Address;
154    if (bus_set_resource(dev, rtype, rid, rstart, rlen))
155	device_printf(dev, "couldn't set resource (%s 0x%jx+0x%jx)\n",
156	    (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen);
157    return_VOID;
158}
159
160static int
161acpi_timer_probe(device_t dev)
162{
163    char desc[40];
164    int i, j, rid, rtype;
165
166    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
167
168    if (dev != acpi_timer_dev)
169	return (ENXIO);
170
171    switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
172    case ACPI_ADR_SPACE_SYSTEM_MEMORY:
173	rtype = SYS_RES_MEMORY;
174	break;
175    case ACPI_ADR_SPACE_SYSTEM_IO:
176	rtype = SYS_RES_IOPORT;
177	break;
178    default:
179	return (ENXIO);
180    }
181    rid = 0;
182    acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
183    if (acpi_timer_reg == NULL) {
184	device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n",
185	    (rtype == SYS_RES_IOPORT) ? "port" : "mem",
186	    (u_long)AcpiGbl_FADT.XPmTimerBlock.Address);
187	return (ENXIO);
188    }
189    acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
190    acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
191    if (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER)
192	acpi_timer_timecounter.tc_counter_mask = 0xffffffff;
193    else
194	acpi_timer_timecounter.tc_counter_mask = 0x00ffffff;
195    acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
196    acpi_timer_timecounter.tc_flags = TC_FLAGS_SUSPEND_SAFE;
197    if (testenv("debug.acpi.timer_test"))
198	acpi_timer_boot_test();
199
200    /*
201     * If all tests of the counter succeed, use the ACPI-fast method.  If
202     * at least one failed, default to using the safe routine, which reads
203     * the timer multiple times to get a consistent value before returning.
204     */
205    j = 0;
206    if (bootverbose)
207	printf("ACPI timer:");
208    for (i = 0; i < 10; i++)
209	j += acpi_timer_test();
210    if (bootverbose)
211	printf(" -> %d\n", j);
212    if (j == 10) {
213	acpi_timer_timecounter.tc_name = "ACPI-fast";
214	acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
215	acpi_timer_timecounter.tc_quality = 900;
216    } else {
217	acpi_timer_timecounter.tc_name = "ACPI-safe";
218	acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
219	acpi_timer_timecounter.tc_quality = 850;
220    }
221    tc_init(&acpi_timer_timecounter);
222
223    sprintf(desc, "%d-bit timer at %u.%06uMHz",
224	(AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) != 0 ? 32 : 24,
225	acpi_timer_frequency / 1000000, acpi_timer_frequency % 1000000);
226    device_set_desc_copy(dev, desc);
227
228    /* Release the resource, we'll allocate it again during attach. */
229    bus_release_resource(dev, rtype, rid, acpi_timer_reg);
230    return (0);
231}
232
233static int
234acpi_timer_attach(device_t dev)
235{
236    int rid, rtype;
237
238    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
239
240    switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
241    case ACPI_ADR_SPACE_SYSTEM_MEMORY:
242	rtype = SYS_RES_MEMORY;
243	break;
244    case ACPI_ADR_SPACE_SYSTEM_IO:
245	rtype = SYS_RES_IOPORT;
246	break;
247    default:
248	return (ENXIO);
249    }
250    rid = 0;
251    acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
252    if (acpi_timer_reg == NULL)
253	return (ENXIO);
254    acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
255    acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
256
257    /* Register suspend event handler. */
258    if (EVENTHANDLER_REGISTER(power_suspend, acpi_timer_suspend_handler,
259	&acpi_timer_timecounter, EVENTHANDLER_PRI_LAST) == NULL)
260	device_printf(dev, "failed to register suspend event handler\n");
261
262    return (0);
263}
264
265static void
266acpi_timer_resume_handler(struct timecounter *newtc)
267{
268	struct timecounter *tc;
269
270	tc = timecounter;
271	if (tc != newtc) {
272		if (bootverbose)
273			device_printf(acpi_timer_dev,
274			    "restoring timecounter, %s -> %s\n",
275			    tc->tc_name, newtc->tc_name);
276		(void)newtc->tc_get_timecount(newtc);
277		(void)newtc->tc_get_timecount(newtc);
278		timecounter = newtc;
279	}
280}
281
282static void
283acpi_timer_suspend_handler(struct timecounter *newtc)
284{
285	struct timecounter *tc;
286
287	/* Deregister existing resume event handler. */
288	if (acpi_timer_eh != NULL) {
289		EVENTHANDLER_DEREGISTER(power_resume, acpi_timer_eh);
290		acpi_timer_eh = NULL;
291	}
292
293	if ((timecounter->tc_flags & TC_FLAGS_SUSPEND_SAFE) != 0) {
294		/*
295		 * If we are using a suspend safe timecounter, don't
296		 * save/restore it across suspend/resume.
297		 */
298		return;
299	}
300
301	KASSERT(newtc == &acpi_timer_timecounter,
302	    ("acpi_timer_suspend_handler: wrong timecounter"));
303
304	tc = timecounter;
305	if (tc != newtc) {
306		if (bootverbose)
307			device_printf(acpi_timer_dev,
308			    "switching timecounter, %s -> %s\n",
309			    tc->tc_name, newtc->tc_name);
310		(void)acpi_timer_read();
311		(void)acpi_timer_read();
312		timecounter = newtc;
313		acpi_timer_eh = EVENTHANDLER_REGISTER(power_resume,
314		    acpi_timer_resume_handler, tc, EVENTHANDLER_PRI_LAST);
315	}
316}
317
318/*
319 * Fetch current time value from reliable hardware.
320 */
321static u_int
322acpi_timer_get_timecount(struct timecounter *tc)
323{
324    return (acpi_timer_read());
325}
326
327/*
328 * Fetch current time value from hardware that may not correctly
329 * latch the counter.  We need to read until we have three monotonic
330 * samples and then use the middle one, otherwise we are not protected
331 * against the fact that the bits can be wrong in two directions.  If
332 * we only cared about monosity, two reads would be enough.
333 */
334static u_int
335acpi_timer_get_timecount_safe(struct timecounter *tc)
336{
337    u_int u1, u2, u3;
338
339    u2 = acpi_timer_read();
340    u3 = acpi_timer_read();
341    do {
342	u1 = u2;
343	u2 = u3;
344	u3 = acpi_timer_read();
345    } while (u1 > u2 || u2 > u3);
346
347    return (u2);
348}
349
350/*
351 * Timecounter freqency adjustment interface.
352 */
353static int
354acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
355{
356    int error;
357    u_int freq;
358
359    if (acpi_timer_timecounter.tc_frequency == 0)
360	return (EOPNOTSUPP);
361    freq = acpi_timer_frequency;
362    error = sysctl_handle_int(oidp, &freq, 0, req);
363    if (error == 0 && req->newptr != NULL) {
364	acpi_timer_frequency = freq;
365	acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
366    }
367
368    return (error);
369}
370
371SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
372    0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "ACPI timer frequency");
373
374/*
375 * Some ACPI timers are known or believed to suffer from implementation
376 * problems which can lead to erroneous values being read.  This function
377 * tests for consistent results from the timer and returns 1 if it believes
378 * the timer is consistent, otherwise it returns 0.
379 *
380 * It appears the cause is that the counter is not latched to the PCI bus
381 * clock when read:
382 *
383 * ] 20. ACPI Timer Errata
384 * ]
385 * ]   Problem: The power management timer may return improper result when
386 * ]   read. Although the timer value settles properly after incrementing,
387 * ]   while incrementing there is a 3nS window every 69.8nS where the
388 * ]   timer value is indeterminate (a 4.2% chance that the data will be
389 * ]   incorrect when read). As a result, the ACPI free running count up
390 * ]   timer specification is violated due to erroneous reads.  Implication:
391 * ]   System hangs due to the "inaccuracy" of the timer when used by
392 * ]   software for time critical events and delays.
393 * ]
394 * ] Workaround: Read the register twice and compare.
395 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
396 * ] in the PIIX4M.
397 */
398#define N 2000
399static int
400acpi_timer_test()
401{
402    uint32_t last, this;
403    int delta, max, max2, min, n;
404    register_t s;
405
406    min = INT32_MAX;
407    max = max2 = 0;
408
409    /* Test the timer with interrupts disabled to get accurate results. */
410    s = intr_disable();
411    last = acpi_timer_read();
412    for (n = 0; n < N; n++) {
413	this = acpi_timer_read();
414	delta = acpi_TimerDelta(this, last);
415	if (delta > max) {
416	    max2 = max;
417	    max = delta;
418	} else if (delta > max2)
419	    max2 = delta;
420	if (delta < min)
421	    min = delta;
422	last = this;
423    }
424    intr_restore(s);
425
426    delta = max2 - min;
427    if ((max - min > 8 || delta > 3) && vm_guest == VM_GUEST_NO)
428	n = 0;
429    else if (min < 0 || max == 0 || max2 == 0)
430	n = 0;
431    else
432	n = 1;
433    if (bootverbose)
434	printf(" %d/%d", n, delta);
435
436    return (n);
437}
438#undef N
439
440/*
441 * Test harness for verifying ACPI timer behaviour.
442 * Boot with debug.acpi.timer_test set to invoke this.
443 */
444static void
445acpi_timer_boot_test(void)
446{
447    uint32_t u1, u2, u3;
448
449    u1 = acpi_timer_read();
450    u2 = acpi_timer_read();
451    u3 = acpi_timer_read();
452
453    device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
454    for (;;) {
455	/*
456	 * The failure case is where u3 > u1, but u2 does not fall between
457	 * the two, ie. it contains garbage.
458	 */
459	if (u3 > u1) {
460	    if (u2 < u1 || u2 > u3)
461		device_printf(acpi_timer_dev,
462			      "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
463			      u1, u2, u3);
464	}
465	u1 = u2;
466	u2 = u3;
467	u3 = acpi_timer_read();
468    }
469}
470