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#include "opt_acpi.h"
30#include <sys/param.h>
31#include <sys/bus.h>
32#include <sys/eventhandler.h>
33#include <sys/kernel.h>
34#include <sys/module.h>
35#include <sys/sysctl.h>
36#include <sys/timetc.h>
37
38#include <machine/bus.h>
39#include <machine/resource.h>
40#include <sys/rman.h>
41
42#include <contrib/dev/acpica/include/acpi.h>
43#include <contrib/dev/acpica/include/accommon.h>
44
45#include <dev/acpica/acpivar.h>
46#include <dev/pci/pcivar.h>
47
48/*
49 * A timecounter based on the free-running ACPI timer.
50 *
51 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
52 */
53
54/* Hooks for the ACPI CA debugging infrastructure */
55#define _COMPONENT	ACPI_TIMER
56ACPI_MODULE_NAME("TIMER")
57
58static device_t			acpi_timer_dev;
59static struct resource		*acpi_timer_reg;
60static bus_space_handle_t	acpi_timer_bsh;
61static bus_space_tag_t		acpi_timer_bst;
62static eventhandler_tag		acpi_timer_eh;
63
64static u_int	acpi_timer_frequency = 14318182 / 4;
65
66/* Knob to disable acpi_timer device */
67bool acpi_timer_disabled = false;
68
69static void	acpi_timer_identify(driver_t *driver, device_t parent);
70static int	acpi_timer_probe(device_t dev);
71static int	acpi_timer_attach(device_t dev);
72static void	acpi_timer_resume_handler(struct timecounter *);
73static void	acpi_timer_suspend_handler(struct timecounter *);
74static u_int	acpi_timer_get_timecount(struct timecounter *tc);
75static u_int	acpi_timer_get_timecount_safe(struct timecounter *tc);
76static int	acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
77static void	acpi_timer_boot_test(void);
78
79static int	acpi_timer_test(void);
80static int	acpi_timer_test_enabled = 0;
81TUNABLE_INT("hw.acpi.timer_test_enabled", &acpi_timer_test_enabled);
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
97DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, 0, 0);
98MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1);
99
100static struct timecounter acpi_timer_timecounter = {
101	acpi_timer_get_timecount_safe,	/* get_timecount function */
102	0,				/* no poll_pps */
103	0,				/* no default counter_mask */
104	0,				/* no default frequency */
105	"ACPI",				/* name */
106	-1				/* quality (chosen later) */
107};
108
109static __inline uint32_t
110acpi_timer_read(void)
111{
112
113    return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0));
114}
115
116/*
117 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
118 * we will be using.
119 */
120static void
121acpi_timer_identify(driver_t *driver, device_t parent)
122{
123    device_t dev;
124    rman_res_t rlen, rstart;
125    int rid, rtype;
126
127    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
128
129    if (acpi_disabled("timer") || (acpi_quirks & ACPI_Q_TIMER) ||
130	acpi_timer_dev || acpi_timer_disabled ||
131	AcpiGbl_FADT.PmTimerLength == 0)
132	return_VOID;
133
134    if ((dev = BUS_ADD_CHILD(parent, 2, "acpi_timer", 0)) == NULL) {
135	device_printf(parent, "could not add acpi_timer0\n");
136	return_VOID;
137    }
138    acpi_timer_dev = dev;
139
140    switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
141    case ACPI_ADR_SPACE_SYSTEM_MEMORY:
142	rtype = SYS_RES_MEMORY;
143	break;
144    case ACPI_ADR_SPACE_SYSTEM_IO:
145	rtype = SYS_RES_IOPORT;
146	break;
147    default:
148	return_VOID;
149    }
150    rid = 0;
151    rlen = AcpiGbl_FADT.PmTimerLength;
152    rstart = AcpiGbl_FADT.XPmTimerBlock.Address;
153    if (bus_set_resource(dev, rtype, rid, rstart, rlen))
154	device_printf(dev, "couldn't set resource (%s 0x%jx+0x%jx)\n",
155	    (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen);
156    return_VOID;
157}
158
159static int
160acpi_timer_probe(device_t dev)
161{
162    int i, j, rid, rtype;
163
164    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
165
166    if (dev != acpi_timer_dev)
167	return (ENXIO);
168
169    switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
170    case ACPI_ADR_SPACE_SYSTEM_MEMORY:
171	rtype = SYS_RES_MEMORY;
172	break;
173    case ACPI_ADR_SPACE_SYSTEM_IO:
174	rtype = SYS_RES_IOPORT;
175	break;
176    default:
177	return (ENXIO);
178    }
179    rid = 0;
180    acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
181    if (acpi_timer_reg == NULL) {
182	device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n",
183	    (rtype == SYS_RES_IOPORT) ? "port" : "mem",
184	    (u_long)AcpiGbl_FADT.XPmTimerBlock.Address);
185	return (ENXIO);
186    }
187    acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
188    acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
189    if (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER)
190	acpi_timer_timecounter.tc_counter_mask = 0xffffffff;
191    else
192	acpi_timer_timecounter.tc_counter_mask = 0x00ffffff;
193    acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
194    acpi_timer_timecounter.tc_flags = TC_FLAGS_SUSPEND_SAFE;
195    if (testenv("debug.acpi.timer_test"))
196	acpi_timer_boot_test();
197
198    /*
199     * If all tests of the counter succeed, use the ACPI-fast method.  If
200     * at least one failed, default to using the safe routine, which reads
201     * the timer multiple times to get a consistent value before returning.
202     */
203    j = 0;
204    if (bootverbose)
205	printf("ACPI timer:");
206    for (i = 0; i < 10; i++)
207	j += acpi_timer_test();
208    if (bootverbose)
209	printf(" -> %d\n", j);
210    if (j == 10) {
211	acpi_timer_timecounter.tc_name = "ACPI-fast";
212	acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
213	acpi_timer_timecounter.tc_quality = 900;
214    } else {
215	acpi_timer_timecounter.tc_name = "ACPI-safe";
216	acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
217	acpi_timer_timecounter.tc_quality = 850;
218    }
219    tc_init(&acpi_timer_timecounter);
220
221    device_set_descf(dev, "%d-bit timer at %u.%06uMHz",
222	(AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) != 0 ? 32 : 24,
223	acpi_timer_frequency / 1000000, acpi_timer_frequency % 1000000);
224
225    /* Release the resource, we'll allocate it again during attach. */
226    bus_release_resource(dev, rtype, rid, acpi_timer_reg);
227    return (0);
228}
229
230static int
231acpi_timer_attach(device_t dev)
232{
233    int rid, rtype;
234
235    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
236
237    switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
238    case ACPI_ADR_SPACE_SYSTEM_MEMORY:
239	rtype = SYS_RES_MEMORY;
240	break;
241    case ACPI_ADR_SPACE_SYSTEM_IO:
242	rtype = SYS_RES_IOPORT;
243	break;
244    default:
245	return (ENXIO);
246    }
247    rid = 0;
248    acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
249    if (acpi_timer_reg == NULL)
250	return (ENXIO);
251    acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
252    acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
253
254    /* Register suspend event handler. */
255    if (EVENTHANDLER_REGISTER(power_suspend, acpi_timer_suspend_handler,
256	&acpi_timer_timecounter, EVENTHANDLER_PRI_LAST) == NULL)
257	device_printf(dev, "failed to register suspend event handler\n");
258
259    return (0);
260}
261
262static void
263acpi_timer_resume_handler(struct timecounter *newtc)
264{
265	struct timecounter *tc;
266
267	tc = timecounter;
268	if (tc != newtc) {
269		if (bootverbose)
270			device_printf(acpi_timer_dev,
271			    "restoring timecounter, %s -> %s\n",
272			    tc->tc_name, newtc->tc_name);
273		(void)newtc->tc_get_timecount(newtc);
274		timecounter = newtc;
275	}
276}
277
278static void
279acpi_timer_suspend_handler(struct timecounter *newtc)
280{
281	struct timecounter *tc;
282
283	/* Deregister existing resume event handler. */
284	if (acpi_timer_eh != NULL) {
285		EVENTHANDLER_DEREGISTER(power_resume, acpi_timer_eh);
286		acpi_timer_eh = NULL;
287	}
288
289	if ((timecounter->tc_flags & TC_FLAGS_SUSPEND_SAFE) != 0) {
290		/*
291		 * If we are using a suspend safe timecounter, don't
292		 * save/restore it across suspend/resume.
293		 */
294		return;
295	}
296
297	KASSERT(newtc == &acpi_timer_timecounter,
298	    ("acpi_timer_suspend_handler: wrong timecounter"));
299
300	tc = timecounter;
301	if (tc != newtc) {
302		if (bootverbose)
303			device_printf(acpi_timer_dev,
304			    "switching timecounter, %s -> %s\n",
305			    tc->tc_name, newtc->tc_name);
306		(void)acpi_timer_read();
307		(void)acpi_timer_read();
308		timecounter = newtc;
309		acpi_timer_eh = EVENTHANDLER_REGISTER(power_resume,
310		    acpi_timer_resume_handler, tc, EVENTHANDLER_PRI_LAST);
311	}
312}
313
314/*
315 * Fetch current time value from reliable hardware.
316 */
317static u_int
318acpi_timer_get_timecount(struct timecounter *tc)
319{
320    return (acpi_timer_read());
321}
322
323/*
324 * Fetch current time value from hardware that may not correctly
325 * latch the counter.  We need to read until we have three monotonic
326 * samples and then use the middle one, otherwise we are not protected
327 * against the fact that the bits can be wrong in two directions.  If
328 * we only cared about monosity, two reads would be enough.
329 */
330static u_int
331acpi_timer_get_timecount_safe(struct timecounter *tc)
332{
333    u_int u1, u2, u3;
334
335    u2 = acpi_timer_read();
336    u3 = acpi_timer_read();
337    do {
338	u1 = u2;
339	u2 = u3;
340	u3 = acpi_timer_read();
341    } while (u1 > u2 || u2 > u3);
342
343    return (u2);
344}
345
346/*
347 * Timecounter freqency adjustment interface.
348 */
349static int
350acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
351{
352    int error;
353    u_int freq;
354
355    if (acpi_timer_timecounter.tc_frequency == 0)
356	return (EOPNOTSUPP);
357    freq = acpi_timer_frequency;
358    error = sysctl_handle_int(oidp, &freq, 0, req);
359    if (error == 0 && req->newptr != NULL) {
360	acpi_timer_frequency = freq;
361	acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
362    }
363
364    return (error);
365}
366
367SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq,
368    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0,
369    acpi_timer_sysctl_freq, "I",
370    "ACPI timer frequency");
371
372/*
373 * Some ACPI timers are known or believed to suffer from implementation
374 * problems which can lead to erroneous values being read.  This function
375 * tests for consistent results from the timer and returns 1 if it believes
376 * the timer is consistent, otherwise it returns 0.
377 *
378 * It appears the cause is that the counter is not latched to the PCI bus
379 * clock when read:
380 *
381 * ] 20. ACPI Timer Errata
382 * ]
383 * ]   Problem: The power management timer may return improper result when
384 * ]   read. Although the timer value settles properly after incrementing,
385 * ]   while incrementing there is a 3nS window every 69.8nS where the
386 * ]   timer value is indeterminate (a 4.2% chance that the data will be
387 * ]   incorrect when read). As a result, the ACPI free running count up
388 * ]   timer specification is violated due to erroneous reads.  Implication:
389 * ]   System hangs due to the "inaccuracy" of the timer when used by
390 * ]   software for time critical events and delays.
391 * ]
392 * ] Workaround: Read the register twice and compare.
393 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
394 * ] in the PIIX4M.
395 */
396#define N 2000
397static int
398acpi_timer_test(void)
399{
400    uint32_t last, this;
401    int delta, max, max2, min, n;
402    register_t s;
403
404    /* Skip the test based on the hw.acpi.timer_test_enabled tunable. */
405    if (!acpi_timer_test_enabled)
406	return (1);
407
408    TSENTER();
409
410    min = INT32_MAX;
411    max = max2 = 0;
412
413    /* Test the timer with interrupts disabled to get accurate results. */
414    s = intr_disable();
415    last = acpi_timer_read();
416    for (n = 0; n < N; n++) {
417	this = acpi_timer_read();
418	delta = acpi_TimerDelta(this, last);
419	if (delta > max) {
420	    max2 = max;
421	    max = delta;
422	} else if (delta > max2)
423	    max2 = delta;
424	if (delta < min)
425	    min = delta;
426	last = this;
427    }
428    intr_restore(s);
429
430    delta = max2 - min;
431    if ((max - min > 8 || delta > 3) && vm_guest == VM_GUEST_NO)
432	n = 0;
433    else if (min < 0 || max == 0 || max2 == 0)
434	n = 0;
435    else
436	n = 1;
437    if (bootverbose)
438	printf(" %d/%d", n, delta);
439
440    TSEXIT();
441
442    return (n);
443}
444#undef N
445
446/*
447 * Test harness for verifying ACPI timer behaviour.
448 * Boot with debug.acpi.timer_test set to invoke this.
449 */
450static void
451acpi_timer_boot_test(void)
452{
453    uint32_t u1, u2, u3;
454
455    u1 = acpi_timer_read();
456    u2 = acpi_timer_read();
457    u3 = acpi_timer_read();
458
459    device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
460    for (;;) {
461	/*
462	 * The failure case is where u3 > u1, but u2 does not fall between
463	 * the two, ie. it contains garbage.
464	 */
465	if (u3 > u1) {
466	    if (u2 < u1 || u2 > u3)
467		device_printf(acpi_timer_dev,
468			      "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
469			      u1, u2, u3);
470	}
471	u1 = u2;
472	u2 = u3;
473	u3 = acpi_timer_read();
474    }
475}
476