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: releng/5.3/sys/dev/acpica/acpi_timer.c 136340 2004-10-10 03:15:45Z njl $
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/timetc.h>
36
37 #include <machine/bus.h>
38 #include <machine/resource.h>
39 #include <sys/rman.h>
40
41 #include "acpi.h"
42 #include <dev/acpica/acpivar.h>
43 #include <dev/pci/pcivar.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
60 static u_int acpi_timer_frequency = 14318182 / 4;
61
62 static void acpi_timer_identify(driver_t *driver, device_t parent);
63 static int acpi_timer_probe(device_t dev);
64 static int acpi_timer_attach(device_t dev);
65 static u_int acpi_timer_get_timecount(struct timecounter *tc);
66 static u_int acpi_timer_get_timecount_safe(struct timecounter *tc);
67 static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
68 static void acpi_timer_boot_test(void);
69
70 static u_int acpi_timer_read(void);
71 static int acpi_timer_test(void);
72
73 static device_method_t acpi_timer_methods[] = {
74 DEVMETHOD(device_identify, acpi_timer_identify),
75 DEVMETHOD(device_probe, acpi_timer_probe),
76 DEVMETHOD(device_attach, acpi_timer_attach),
77
78 {0, 0}
79 };
80
81 static driver_t acpi_timer_driver = {
82 "acpi_timer",
83 acpi_timer_methods,
84 0,
85 };
86
87 static devclass_t acpi_timer_devclass;
88 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
89 MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1);
90
91 static struct timecounter acpi_timer_timecounter = {
92 acpi_timer_get_timecount_safe, /* get_timecount function */
93 0, /* no poll_pps */
94 0, /* no default counter_mask */
95 0, /* no default frequency */
96 "ACPI", /* name */
97 1000 /* quality */
98 };
99
100 static u_int
101 acpi_timer_read()
102 {
103 return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0));
104 }
105
106 /*
107 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
108 * we will be using.
109 */
110 static void
111 acpi_timer_identify(driver_t *driver, device_t parent)
112 {
113 device_t dev;
114 u_long rlen, rstart;
115 int rid, rtype;
116
117 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
118
119 if (acpi_disabled("timer") || (acpi_quirks & ACPI_Q_TIMER) ||
120 AcpiGbl_FADT == NULL || acpi_timer_dev)
121 return_VOID;
122
123 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) {
124 device_printf(parent, "could not add acpi_timer0\n");
125 return_VOID;
126 }
127 acpi_timer_dev = dev;
128
129 rid = 0;
130 rtype = AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId ?
131 SYS_RES_IOPORT : SYS_RES_MEMORY;
132 rlen = AcpiGbl_FADT->PmTmLen;
133 rstart = AcpiGbl_FADT->XPmTmrBlk.Address;
134 if (bus_set_resource(dev, rtype, rid, rstart, rlen))
135 device_printf(dev, "couldn't set resource (%s 0x%lx+0x%lx)\n",
136 (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen);
137 return_VOID;
138 }
139
140 static int
141 acpi_timer_probe(device_t dev)
142 {
143 char desc[40];
144 int i, j, rid, rtype;
145
146 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
147
148 if (dev != acpi_timer_dev)
149 return (ENXIO);
150
151 rid = 0;
152 rtype = AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId ?
153 SYS_RES_IOPORT : SYS_RES_MEMORY;
154 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
155 if (acpi_timer_reg == NULL) {
156 device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n",
157 (rtype == SYS_RES_IOPORT) ? "port" : "mem",
158 (u_long)AcpiGbl_FADT->XPmTmrBlk.Address);
159 return (ENXIO);
160 }
161 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
162 acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
163 if (AcpiGbl_FADT->TmrValExt != 0)
164 acpi_timer_timecounter.tc_counter_mask = 0xffffffff;
165 else
166 acpi_timer_timecounter.tc_counter_mask = 0x00ffffff;
167 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
168 if (testenv("debug.acpi.timer_test"))
169 acpi_timer_boot_test();
170
171 /*
172 * If all tests of the counter succeed, use the ACPI-fast method. If
173 * at least one failed, default to using the safe routine, which reads
174 * the timer multiple times to get a consistent value before returning.
175 */
176 j = 0;
177 for (i = 0; i < 10; i++)
178 j += acpi_timer_test();
179 if (j == 10) {
180 acpi_timer_timecounter.tc_name = "ACPI-fast";
181 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
182 } else {
183 acpi_timer_timecounter.tc_name = "ACPI-safe";
184 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
185 }
186 tc_init(&acpi_timer_timecounter);
187
188 sprintf(desc, "%d-bit timer at 3.579545MHz",
189 AcpiGbl_FADT->TmrValExt ? 32 : 24);
190 device_set_desc_copy(dev, desc);
191
192 /* Release the resource, we'll allocate it again during attach. */
193 bus_release_resource(dev, rtype, rid, acpi_timer_reg);
194 return (0);
195 }
196
197 static int
198 acpi_timer_attach(device_t dev)
199 {
200 int rid, rtype;
201
202 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
203
204 rid = 0;
205 rtype = AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId ?
206 SYS_RES_IOPORT : SYS_RES_MEMORY;
207 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
208 if (acpi_timer_reg == NULL)
209 return (ENXIO);
210 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
211 acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
212 return (0);
213 }
214
215 /*
216 * Fetch current time value from reliable hardware.
217 */
218 static u_int
219 acpi_timer_get_timecount(struct timecounter *tc)
220 {
221 return (acpi_timer_read());
222 }
223
224 /*
225 * Fetch current time value from hardware that may not correctly
226 * latch the counter. We need to read until we have three monotonic
227 * samples and then use the middle one, otherwise we are not protected
228 * against the fact that the bits can be wrong in two directions. If
229 * we only cared about monosity, two reads would be enough.
230 */
231 static u_int
232 acpi_timer_get_timecount_safe(struct timecounter *tc)
233 {
234 u_int u1, u2, u3;
235
236 u2 = acpi_timer_read();
237 u3 = acpi_timer_read();
238 do {
239 u1 = u2;
240 u2 = u3;
241 u3 = acpi_timer_read();
242 } while (u1 > u2 || u2 > u3);
243
244 return (u2);
245 }
246
247 /*
248 * Timecounter freqency adjustment interface.
249 */
250 static int
251 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
252 {
253 int error;
254 u_int freq;
255
256 if (acpi_timer_timecounter.tc_frequency == 0)
257 return (EOPNOTSUPP);
258 freq = acpi_timer_frequency;
259 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
260 if (error == 0 && req->newptr != NULL) {
261 acpi_timer_frequency = freq;
262 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
263 }
264
265 return (error);
266 }
267
268 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
269 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
270
271 /*
272 * Some ACPI timers are known or believed to suffer from implementation
273 * problems which can lead to erroneous values being read. This function
274 * tests for consistent results from the timer and returns 1 if it believes
275 * the timer is consistent, otherwise it returns 0.
276 *
277 * It appears the cause is that the counter is not latched to the PCI bus
278 * clock when read:
279 *
280 * ] 20. ACPI Timer Errata
281 * ]
282 * ] Problem: The power management timer may return improper result when
283 * ] read. Although the timer value settles properly after incrementing,
284 * ] while incrementing there is a 3nS window every 69.8nS where the
285 * ] timer value is indeterminate (a 4.2% chance that the data will be
286 * ] incorrect when read). As a result, the ACPI free running count up
287 * ] timer specification is violated due to erroneous reads. Implication:
288 * ] System hangs due to the "inaccuracy" of the timer when used by
289 * ] software for time critical events and delays.
290 * ]
291 * ] Workaround: Read the register twice and compare.
292 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
293 * ] in the PIIX4M.
294 */
295 #define N 2000
296 static int
297 acpi_timer_test()
298 {
299 uint32_t last, this;
300 int min, max, n, delta;
301 register_t s;
302
303 min = 10000000;
304 max = 0;
305
306 /* Test the timer with interrupts disabled to get accurate results. */
307 s = intr_disable();
308 last = acpi_timer_read();
309 for (n = 0; n < N; n++) {
310 this = acpi_timer_read();
311 delta = acpi_TimerDelta(this, last);
312 if (delta > max)
313 max = delta;
314 else if (delta < min)
315 min = delta;
316 last = this;
317 }
318 intr_restore(s);
319
320 if (max - min > 2)
321 n = 0;
322 else if (min < 0 || max == 0)
323 n = 0;
324 else
325 n = 1;
326 if (bootverbose) {
327 printf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
328 n ? "GOOD" : "BAD ",
329 min, max, max - min);
330 }
331
332 return (n);
333 }
334 #undef N
335
336 /*
337 * Test harness for verifying ACPI timer behaviour.
338 * Boot with debug.acpi.timer_test set to invoke this.
339 */
340 static void
341 acpi_timer_boot_test(void)
342 {
343 uint32_t u1, u2, u3;
344
345 u1 = acpi_timer_read();
346 u2 = acpi_timer_read();
347 u3 = acpi_timer_read();
348
349 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
350 for (;;) {
351 /*
352 * The failure case is where u3 > u1, but u2 does not fall between
353 * the two, ie. it contains garbage.
354 */
355 if (u3 > u1) {
356 if (u2 < u1 || u2 > u3)
357 device_printf(acpi_timer_dev,
358 "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
359 u1, u2, u3);
360 }
361 u1 = u2;
362 u2 = u3;
363 u3 = acpi_timer_read();
364 }
365 }
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