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/5.0/sys/dev/acpica/acpi_timer.c 105281 2002-10-16 17:27:40Z jhb $
28 */
29 #include "opt_acpi.h"
30 #include <sys/param.h>
31 #include <sys/bus.h>
32 #include <sys/kernel.h>
33 #include <sys/sysctl.h>
34 #if __FreeBSD_version >= 500000
35 #include <sys/timetc.h>
36 #else
37 #include <sys/time.h>
38 #endif
39
40 #include <machine/bus_pio.h>
41 #include <machine/bus.h>
42 #include <machine/resource.h>
43 #include <sys/rman.h>
44
45 #include "acpi.h"
46
47 #include <dev/acpica/acpivar.h>
48 #include <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 /*
57 * Hooks for the ACPI CA debugging infrastructure
58 */
59 #define _COMPONENT ACPI_SYSTEM
60 ACPI_MODULE_NAME("TIMER")
61
62 static device_t acpi_timer_dev;
63 struct resource *acpi_timer_reg;
64 #define TIMER_READ bus_space_read_4(rman_get_bustag(acpi_timer_reg), \
65 rman_get_bushandle(acpi_timer_reg), \
66 0)
67
68 static u_int acpi_timer_frequency = 14318182/4;
69
70 static void acpi_timer_identify(driver_t *driver, device_t parent);
71 static int acpi_timer_probe(device_t dev);
72 static int acpi_timer_attach(device_t dev);
73 static unsigned acpi_timer_get_timecount(struct timecounter *tc);
74 static unsigned acpi_timer_get_timecount_safe(struct timecounter *tc);
75 static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
76 static void acpi_timer_test(void);
77
78 /*
79 * Driver hung off ACPI.
80 */
81 static device_method_t acpi_timer_methods[] = {
82 DEVMETHOD(device_identify, acpi_timer_identify),
83 DEVMETHOD(device_probe, acpi_timer_probe),
84 DEVMETHOD(device_attach, acpi_timer_attach),
85
86 {0, 0}
87 };
88
89 static driver_t acpi_timer_driver = {
90 "acpi_timer",
91 acpi_timer_methods,
92 0,
93 };
94
95 static devclass_t acpi_timer_devclass;
96 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
97
98 /*
99 * Timecounter.
100 */
101 static struct timecounter acpi_timer_timecounter = {
102 acpi_timer_get_timecount_safe,
103 0,
104 0xffffff,
105 0,
106 "ACPI"
107 };
108
109 static int test_counter(void);
110
111 #define N 2000
112 static int
113 test_counter()
114 {
115 int min, max, n, delta;
116 unsigned last, this;
117
118 min = 10000000;
119 max = 0;
120 last = TIMER_READ;
121 for (n = 0; n < N; n++) {
122 this = TIMER_READ;
123 delta = (this - last) & 0xffffff;
124 if (delta > max)
125 max = delta;
126 else if (delta < min)
127 min = delta;
128 last = this;
129 }
130 if (max - min > 2)
131 n = 0;
132 else if (min < 0)
133 n = 0;
134 else
135 n = 1;
136 if (bootverbose)
137 printf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
138 n ? "GOOD" : "BAD ",
139 min, max, max - min + 1);
140 return (n);
141 }
142
143 /*
144 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
145 * we will be using.
146 */
147 static void
148 acpi_timer_identify(driver_t *driver, device_t parent)
149 {
150 device_t dev;
151 char desc[40];
152 int rid, i, j;
153
154 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
155
156 if (acpi_disabled("timer"))
157 return_VOID;
158
159 if (AcpiGbl_FADT == NULL)
160 return_VOID;
161
162 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) {
163 device_printf(parent, "could not add acpi_timer0\n");
164 return_VOID;
165 }
166 acpi_timer_dev = dev;
167 rid = 0;
168 bus_set_resource(dev, SYS_RES_IOPORT, rid, AcpiGbl_FADT->V1_PmTmrBlk, sizeof(u_int32_t));
169 if ((acpi_timer_reg = bus_alloc_resource(dev, SYS_RES_IOPORT, &rid, 0, ~0, 1, RF_ACTIVE)) == NULL) {
170 device_printf(dev, "couldn't allocate I/O resource (port 0x%x)\n", AcpiGbl_FADT->V1_PmTmrBlk);
171 return_VOID;
172 }
173 if (testenv("debug.acpi.timer_test"))
174 acpi_timer_test();
175
176 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
177 j = 0;
178 for(i = 0; i < 10; i++)
179 j += test_counter();
180 if (j == 10) {
181 acpi_timer_timecounter.tc_name = "ACPI-fast";
182 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
183 } else {
184 acpi_timer_timecounter.tc_name = "ACPI-safe";
185 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
186 }
187 tc_init(&acpi_timer_timecounter);
188
189 sprintf(desc, "%d-bit timer at 3.579545MHz", AcpiGbl_FADT->TmrValExt ? 32 : 24);
190 device_set_desc_copy(dev, desc);
191
192 return_VOID;
193 }
194
195 static int
196 acpi_timer_probe(device_t dev)
197 {
198 if (dev == acpi_timer_dev)
199 return(0);
200 return(ENXIO);
201 }
202
203 static int
204 acpi_timer_attach(device_t dev)
205 {
206 return(0);
207 }
208
209 /*
210 * Fetch current time value from reliable hardware.
211 */
212 static unsigned
213 acpi_timer_get_timecount(struct timecounter *tc)
214 {
215 return(TIMER_READ);
216 }
217
218 /*
219 * Fetch current time value from hardware that may not correctly
220 * latch the counter.
221 */
222 static unsigned
223 acpi_timer_get_timecount_safe(struct timecounter *tc)
224 {
225 unsigned u1, u2, u3;
226
227 u2 = TIMER_READ;
228 u3 = TIMER_READ;
229 do {
230 u1 = u2;
231 u2 = u3;
232 u3 = TIMER_READ;
233 } while (u1 > u2 || u2 > u3 || (u3 - u1) > 15);
234 return (u2);
235 }
236
237 /*
238 * Timecounter freqency adjustment interface.
239 */
240 static int
241 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
242 {
243 int error;
244 u_int freq;
245
246 if (acpi_timer_timecounter.tc_frequency == 0)
247 return (EOPNOTSUPP);
248 freq = acpi_timer_frequency;
249 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
250 if (error == 0 && req->newptr != NULL) {
251 acpi_timer_frequency = freq;
252 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
253 }
254 return (error);
255 }
256
257 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
258 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
259
260 /*
261 * Test harness for verifying ACPI timer behaviour.
262 * Boot with debug.acpi.timer_test set to invoke this.
263 */
264 static void
265 acpi_timer_test(void)
266 {
267 u_int32_t u1, u2, u3;
268
269 u1 = TIMER_READ;
270 u2 = TIMER_READ;
271 u3 = TIMER_READ;
272
273 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
274 for (;;) {
275 /*
276 * The failure case is where u3 > u1, but u2 does not fall between the two,
277 * ie. it contains garbage.
278 */
279 if (u3 > u1) {
280 if ((u2 < u1) || (u2 > u3))
281 device_printf(acpi_timer_dev, "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
282 u1, u2, u3);
283 }
284 u1 = u2;
285 u2 = u3;
286 u3 = TIMER_READ;
287 }
288 }
289
290 /*
291 * Chipset workaround driver hung off PCI.
292 *
293 * Some ACPI timers are known or believed to suffer from implementation
294 * problems which can lead to erroneous values being read from the timer.
295 *
296 * Since we can't trust unknown chipsets, we default to a timer-read
297 * routine which compensates for the most common problem (as detailed
298 * in the excerpt from the Intel PIIX4 datasheet below).
299 *
300 * When we detect a known-functional chipset, we disable the workaround
301 * to improve speed.
302 *
303 * ] 20. ACPI Timer Errata
304 * ]
305 * ] Problem: The power management timer may return improper result when
306 * ] read. Although the timer value settles properly after incrementing,
307 * ] while incrementing there is a 3nS window every 69.8nS where the
308 * ] timer value is indeterminate (a 4.2% chance that the data will be
309 * ] incorrect when read). As a result, the ACPI free running count up
310 * ] timer specification is violated due to erroneous reads. Implication:
311 * ] System hangs due to the "inaccuracy" of the timer when used by
312 * ] software for time critical events and delays.
313 * ]
314 * ] Workaround: Read the register twice and compare.
315 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
316 * ] in the PIIX4M.
317 *
318 * The counter is in other words not latched to the PCI bus clock when
319 * read. Notice the workaround isn't: We need to read until we have
320 * three monotonic samples and then use the middle one, otherwise we are
321 * not protected against the fact that the bits can be wrong in two
322 * directions. If we only cared about monosity two reads would be enough.
323 */
324
325 #if 0
326 static int acpi_timer_pci_probe(device_t dev);
327
328 static device_method_t acpi_timer_pci_methods[] = {
329 DEVMETHOD(device_probe, acpi_timer_pci_probe),
330 {0, 0}
331 };
332
333 static driver_t acpi_timer_pci_driver = {
334 "acpi_timer_pci",
335 acpi_timer_pci_methods,
336 0,
337 };
338
339 devclass_t acpi_timer_pci_devclass;
340 DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver, acpi_timer_pci_devclass, 0, 0);
341
342 /*
343 * Look at PCI devices going past; if we detect one we know contains
344 * a functional ACPI timer device, enable the faster timecounter read
345 * routine.
346 */
347 static int
348 acpi_timer_pci_probe(device_t dev)
349 {
350 int vendor, device, revid;
351
352 vendor = pci_get_vendor(dev);
353 device = pci_get_device(dev);
354 revid = pci_get_revid(dev);
355
356 if (((vendor == 0x8086) && (device == 0x7113) && (revid >= 0x03)) || /* PIIX4M */
357 ((vendor == 0x8086) && (device == 0x719b)) || /* i440MX */
358 0) {
359
360 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
361 acpi_timer_timecounter.tc_name = "ACPI-fast";
362 if (bootverbose)
363 device_printf(acpi_timer_dev, "functional ACPI timer detected, enabling fast timecount interface\n");
364 }
365
366 return(ENXIO); /* we never match anything */
367 }
368 #endif
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