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 * $FreeBSD: src/sys/dev/acpica/acpi_timer.c,v 1.35 2004/07/22 05:42:14 njl Exp $
28 */
29 #include "opt_acpi.h"
30 #include <sys/param.h>
31 #include <sys/bus.h>
32 #include <sys/kernel.h>
33 #include <sys/module.h>
34 #include <sys/sysctl.h>
35 #include <sys/systimer.h>
36 #include <sys/rman.h>
37
38 #include <machine/lock.h>
39 #include <bus/pci/pcivar.h>
40
41 #include "acpi.h"
42 #include "accommon.h"
43 #include "acpivar.h"
44
45 /*
46 * A timecounter based on the free-running ACPI timer.
47 *
48 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
49 */
50
51 /* Hooks for the ACPI CA debugging infrastructure */
52 #define _COMPONENT ACPI_TIMER
53 ACPI_MODULE_NAME("TIMER")
54
55 static device_t acpi_timer_dev;
56 static struct resource *acpi_timer_reg;
57 static bus_space_handle_t acpi_timer_bsh;
58 static bus_space_tag_t acpi_timer_bst;
59 static sysclock_t acpi_counter_mask;
60 static sysclock_t acpi_last_counter;
61
62 #define ACPI_TIMER_FREQ (14318182 / 4)
63
64 static sysclock_t acpi_timer_get_timecount(void);
65 static sysclock_t acpi_timer_get_timecount24(void);
66 static sysclock_t acpi_timer_get_timecount_safe(void);
67 static void acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock);
68
69 static struct cputimer acpi_cputimer = {
70 SLIST_ENTRY_INITIALIZER,
71 "ACPI",
72 CPUTIMER_PRI_ACPI,
73 CPUTIMER_ACPI,
74 acpi_timer_get_timecount_safe,
75 cputimer_default_fromhz,
76 cputimer_default_fromus,
77 acpi_timer_construct,
78 cputimer_default_destruct,
79 ACPI_TIMER_FREQ,
80 0, 0, 0
81 };
82
83 static int acpi_timer_identify(driver_t *driver, device_t parent);
84 static int acpi_timer_probe(device_t dev);
85 static int acpi_timer_attach(device_t dev);
86 static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
87
88 static int acpi_timer_test(void);
89
90 static device_method_t acpi_timer_methods[] = {
91 DEVMETHOD(device_identify, acpi_timer_identify),
92 DEVMETHOD(device_probe, acpi_timer_probe),
93 DEVMETHOD(device_attach, acpi_timer_attach),
94
95 DEVMETHOD_END
96 };
97
98 static driver_t acpi_timer_driver = {
99 "acpi_timer",
100 acpi_timer_methods,
101 0,
102 };
103
104 static devclass_t acpi_timer_devclass;
105 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, NULL, NULL);
106 MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1);
107
108 static u_int
109 acpi_timer_read(void)
110 {
111 return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0));
112 }
113
114 /*
115 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
116 * we will be using.
117 */
118 static int
119 acpi_timer_identify(driver_t *driver, device_t parent)
120 {
121 device_t dev;
122 u_long rlen, rstart;
123 int rid, rtype;
124
125 /*
126 * Just try once, do nothing if the 'acpi' bus is rescanned.
127 */
128 if (device_get_state(parent) == DS_ATTACHED)
129 return (0);
130
131 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
132
133 if (acpi_disabled("timer") || acpi_timer_dev)
134 return (ENXIO);
135
136 if ((dev = BUS_ADD_CHILD(parent, parent, 0, "acpi_timer", 0)) == NULL) {
137 device_printf(parent, "could not add acpi_timer0\n");
138 return (ENXIO);
139 }
140 acpi_timer_dev = dev;
141
142 switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
143 case ACPI_ADR_SPACE_SYSTEM_MEMORY:
144 rtype = SYS_RES_MEMORY;
145 break;
146 case ACPI_ADR_SPACE_SYSTEM_IO:
147 rtype = SYS_RES_IOPORT;
148 break;
149 default:
150 return (ENXIO);
151 }
152 rid = 0;
153 rlen = AcpiGbl_FADT.PmTimerLength;
154 rstart = AcpiGbl_FADT.XPmTimerBlock.Address;
155 if (bus_set_resource(dev, rtype, rid, rstart, rlen, -1)) {
156 device_printf(dev, "couldn't set resource (%s 0x%lx+0x%lx)\n",
157 (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen);
158 return (ENXIO);
159 }
160 return (0);
161 }
162
163 static int
164 acpi_timer_probe(device_t dev)
165 {
166 char desc[40];
167 int i, j, rid, rtype;
168
169 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
170
171 if (dev != acpi_timer_dev)
172 return (ENXIO);
173
174 switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
175 case ACPI_ADR_SPACE_SYSTEM_MEMORY:
176 rtype = SYS_RES_MEMORY;
177 break;
178 case ACPI_ADR_SPACE_SYSTEM_IO:
179 rtype = SYS_RES_IOPORT;
180 break;
181 default:
182 return (ENXIO);
183 }
184 rid = 0;
185 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
186 if (acpi_timer_reg == NULL) {
187 device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n",
188 (rtype == SYS_RES_IOPORT) ? "port" : "mem",
189 (u_long)AcpiGbl_FADT.XPmTimerBlock.Address);
190 return (ENXIO);
191 }
192 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
193 acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
194 if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) != 0)
195 acpi_counter_mask = 0xffffffff;
196 else
197 acpi_counter_mask = 0x00ffffff;
198
199 /*
200 * If all tests of the counter succeed, use the ACPI-fast method. If
201 * at least one failed, default to using the safe routine, which reads
202 * the timer multiple times to get a consistent value before returning.
203 */
204 j = 0;
205 for (i = 0; i < 10; i++)
206 j += acpi_timer_test();
207 if (j == 10) {
208 if (acpi_counter_mask == 0xffffffff) {
209 acpi_cputimer.name = "ACPI-fast";
210 acpi_cputimer.count = acpi_timer_get_timecount;
211 } else {
212 acpi_cputimer.name = "ACPI-fast24";
213 acpi_cputimer.count = acpi_timer_get_timecount24;
214 }
215 } else {
216 if (acpi_counter_mask == 0xffffffff)
217 acpi_cputimer.name = "ACPI-safe";
218 else
219 acpi_cputimer.name = "ACPI-safe24";
220 acpi_cputimer.count = acpi_timer_get_timecount_safe;
221 }
222
223 ksprintf(desc, "%d-bit timer at 3.579545MHz",
224 (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) ? 32 : 24);
225 device_set_desc_copy(dev, desc);
226
227 cputimer_register(&acpi_cputimer);
228 cputimer_select(&acpi_cputimer, 0);
229 /* Release the resource, we'll allocate it again during attach. */
230 bus_release_resource(dev, rtype, rid, acpi_timer_reg);
231 return (0);
232 }
233
234 static int
235 acpi_timer_attach(device_t dev)
236 {
237 int rid, rtype;
238
239 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
240
241 switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
242 case ACPI_ADR_SPACE_SYSTEM_MEMORY:
243 rtype = SYS_RES_MEMORY;
244 break;
245 case ACPI_ADR_SPACE_SYSTEM_IO:
246 rtype = SYS_RES_IOPORT;
247 break;
248 default:
249 return (ENXIO);
250 }
251 rid = 0;
252 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
253 if (acpi_timer_reg == NULL)
254 return (ENXIO);
255 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
256 acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
257 return (0);
258 }
259
260 /*
261 * Construct the timer. Adjust the base so the system clock does not
262 * jump weirdly.
263 */
264 static void
265 acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock)
266 {
267 timer->base = 0;
268 timer->base = oldclock - acpi_timer_get_timecount_safe();
269 }
270
271 /*
272 * Fetch current time value from reliable hardware.
273 *
274 * The cputimer interface requires a 32 bit return value. If the ACPI timer
275 * is only 24 bits then we have to keep track of the upper 8 bits on our
276 * own.
277 *
278 * XXX we could probably get away with using a per-cpu field for this and
279 * just use interrupt disablement instead of clock_lock.
280 */
281 static sysclock_t
282 acpi_timer_get_timecount24(void)
283 {
284 sysclock_t counter;
285
286 clock_lock();
287 counter = acpi_timer_read();
288 if (counter < acpi_last_counter)
289 acpi_cputimer.base += 0x01000000;
290 acpi_last_counter = counter;
291 counter += acpi_cputimer.base;
292 clock_unlock();
293 return (counter);
294 }
295
296 static sysclock_t
297 acpi_timer_get_timecount(void)
298 {
299 return (acpi_timer_read() + acpi_cputimer.base);
300 }
301
302 /*
303 * Fetch current time value from hardware that may not correctly
304 * latch the counter. We need to read until we have three monotonic
305 * samples and then use the middle one, otherwise we are not protected
306 * against the fact that the bits can be wrong in two directions. If
307 * we only cared about monosity, two reads would be enough.
308 */
309 static sysclock_t
310 acpi_timer_get_timecount_safe(void)
311 {
312 u_int u1, u2, u3;
313
314 if (acpi_counter_mask != 0xffffffff)
315 clock_lock();
316
317 u2 = acpi_timer_read();
318 u3 = acpi_timer_read();
319 do {
320 u1 = u2;
321 u2 = u3;
322 u3 = acpi_timer_read();
323 } while (u1 > u2 || u2 > u3);
324
325 if (acpi_counter_mask != 0xffffffff) {
326 if (u2 < acpi_last_counter)
327 acpi_cputimer.base += 0x01000000;
328 acpi_last_counter = u2;
329 clock_unlock();
330 }
331 return (u2 + acpi_cputimer.base);
332 }
333
334 /*
335 * Timecounter freqency adjustment interface.
336 */
337 static int
338 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
339 {
340 int error;
341 u_int freq;
342
343 if (acpi_cputimer.freq == 0)
344 return (EOPNOTSUPP);
345 freq = acpi_cputimer.freq;
346 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
347 if (error == 0 && req->newptr != NULL)
348 cputimer_set_frequency(&acpi_cputimer, freq);
349
350 return (error);
351 }
352
353 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
354 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "ACPI timer frequency");
355
356 /*
357 * Some ACPI timers are known or believed to suffer from implementation
358 * problems which can lead to erroneous values being read. This function
359 * tests for consistent results from the timer and returns 1 if it believes
360 * the timer is consistent, otherwise it returns 0.
361 *
362 * It appears the cause is that the counter is not latched to the PCI bus
363 * clock when read:
364 *
365 * ] 20. ACPI Timer Errata
366 * ]
367 * ] Problem: The power management timer may return improper result when
368 * ] read. Although the timer value settles properly after incrementing,
369 * ] while incrementing there is a 3nS window every 69.8nS where the
370 * ] timer value is indeterminate (a 4.2% chance that the data will be
371 * ] incorrect when read). As a result, the ACPI free running count up
372 * ] timer specification is violated due to erroneous reads. Implication:
373 * ] System hangs due to the "inaccuracy" of the timer when used by
374 * ] software for time critical events and delays.
375 * ]
376 * ] Workaround: Read the register twice and compare.
377 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
378 * ] in the PIIX4M.
379 */
380
381 static int
382 acpi_timer_test(void)
383 {
384 uint32_t last, this;
385 int min, max, n, delta;
386 register_t s;
387
388 min = 10000000;
389 max = 0;
390
391 /* Test the timer with interrupts disabled to get accurate results. */
392 #if defined(__i386__)
393 s = read_eflags();
394 #elif defined(__x86_64__)
395 s = read_rflags();
396 #else
397 #error "no read_eflags"
398 #endif
399 cpu_disable_intr();
400 last = acpi_timer_read();
401 for (n = 0; n < 2000; n++) {
402 this = acpi_timer_read();
403 delta = acpi_TimerDelta(this, last);
404 if (delta > max)
405 max = delta;
406 else if (delta < min)
407 min = delta;
408 last = this;
409 }
410 #if defined(__i386__)
411 write_eflags(s);
412 #elif defined(__x86_64__)
413 write_rflags(s);
414 #else
415 #error "no read_eflags"
416 #endif
417
418 if (max - min > 2)
419 n = 0;
420 else if (min < 0 || max == 0)
421 n = 0;
422 else
423 n = 1;
424 if (bootverbose) {
425 kprintf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
426 n ? "GOOD" : "BAD ",
427 min, max, max - min);
428 }
429
430 return (n);
431 }
432
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