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 *
| 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 *
|
56ACPI_MODULE_NAME("TIMER")
57
58static device_t acpi_timer_dev;
59struct resource *acpi_timer_reg;
60
61static u_int acpi_timer_frequency = 14318182 / 4;
62
63static void acpi_timer_identify(driver_t *driver, device_t parent);
64static int acpi_timer_probe(device_t dev);
65static int acpi_timer_attach(device_t dev);
66static unsigned acpi_timer_get_timecount(struct timecounter *tc);
67static unsigned acpi_timer_get_timecount_safe(struct timecounter *tc);
68static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
69static void acpi_timer_test(void);
70
71static uint32_t read_counter(void);
72static int test_counter(void);
73
74static device_method_t acpi_timer_methods[] = {
75 DEVMETHOD(device_identify, acpi_timer_identify),
76 DEVMETHOD(device_probe, acpi_timer_probe),
77 DEVMETHOD(device_attach, acpi_timer_attach),
78
79 {0, 0}
80};
81
82static driver_t acpi_timer_driver = {
83 "acpi_timer",
84 acpi_timer_methods,
85 0,
86};
87
88static devclass_t acpi_timer_devclass;
89DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
90
91static struct timecounter acpi_timer_timecounter = {
92 acpi_timer_get_timecount_safe,
93 0,
94 0xffffff,
95 0,
96 "ACPI",
97 1000
98};
99
100static uint32_t
101read_counter()
102{
103 bus_space_handle_t bsh;
104 bus_space_tag_t bst;
105 u_int32_t tv;
106
107 bsh = rman_get_bushandle(acpi_timer_reg);
108 bst = rman_get_bustag(acpi_timer_reg);
109 tv = bus_space_read_4(bst, bsh, 0);
110 bus_space_barrier(bst, bsh, 0, 4, BUS_SPACE_BARRIER_READ);
111
112 return (tv);
113}
114
115#define N 2000
116static int
117test_counter()
118{
119 u_int last, this;
120 int min, max, n, delta;
121
122 min = 10000000;
123 max = 0;
124 last = read_counter();
125 for (n = 0; n < N; n++) {
126 this = read_counter();
127 delta = (this - last) & 0xffffff;
128 if (delta > max)
129 max = delta;
130 else if (delta < min)
131 min = delta;
132 last = this;
133 }
134 if (max - min > 2)
135 n = 0;
136 else if (min < 0 || max == 0)
137 n = 0;
138 else
139 n = 1;
140 if (bootverbose) {
141 printf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
142 n ? "GOOD" : "BAD ",
143 min, max, max - min);
144 }
145
146 return (n);
147}
148#undef N
149
150/*
151 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
152 * we will be using.
153 */
154static void
155acpi_timer_identify(driver_t *driver, device_t parent)
156{
157 device_t dev;
158 char desc[40];
159 u_long rlen, rstart;
160 int i, j, rid, rtype;
161
162 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
163
164 if (acpi_disabled("timer") || AcpiGbl_FADT == NULL)
165 return_VOID;
166
167 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) {
168 device_printf(parent, "could not add acpi_timer0\n");
169 return_VOID;
170 }
171 acpi_timer_dev = dev;
172
173 rid = 0;
174 rlen = AcpiGbl_FADT->PmTmLen;
175 rtype = (AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId)
176 ? SYS_RES_IOPORT : SYS_RES_MEMORY;
177 rstart = AcpiGbl_FADT->XPmTmrBlk.Address;
178 bus_set_resource(dev, rtype, rid, rstart, rlen);
179 acpi_timer_reg = bus_alloc_resource(dev, rtype, &rid, 0, ~0, 1, RF_ACTIVE);
180 if (acpi_timer_reg == NULL) {
181 device_printf(dev, "couldn't allocate I/O resource (%s 0x%lx)\n",
182 rtype == SYS_RES_IOPORT ? "port" : "mem", rstart);
183 return_VOID;
184 }
185 if (testenv("debug.acpi.timer_test"))
186 acpi_timer_test();
187
188 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
189 j = 0;
190 for(i = 0; i < 10; i++)
191 j += test_counter();
192 if (j == 10) {
193 acpi_timer_timecounter.tc_name = "ACPI-fast";
194 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
195 } else {
196 acpi_timer_timecounter.tc_name = "ACPI-safe";
197 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
198 }
199 tc_init(&acpi_timer_timecounter);
200
201 sprintf(desc, "%d-bit timer at 3.579545MHz",
202 AcpiGbl_FADT->TmrValExt ? 32 : 24);
203 device_set_desc_copy(dev, desc);
204
205 return_VOID;
206}
207
208static int
209acpi_timer_probe(device_t dev)
210{
211 if (dev == acpi_timer_dev)
212 return (0);
213
214 return (ENXIO);
215}
216
217static int
218acpi_timer_attach(device_t dev)
219{
220 return (0);
221}
222
223/*
224 * Fetch current time value from reliable hardware.
225 */
226static unsigned
227acpi_timer_get_timecount(struct timecounter *tc)
228{
229 return (read_counter());
230}
231
232/*
233 * Fetch current time value from hardware that may not correctly
234 * latch the counter.
235 */
236static unsigned
237acpi_timer_get_timecount_safe(struct timecounter *tc)
238{
239 unsigned u1, u2, u3;
240
241 u2 = read_counter();
242 u3 = read_counter();
243 do {
244 u1 = u2;
245 u2 = u3;
246 u3 = read_counter();
247 } while (u1 > u2 || u2 > u3 || u3 - u1 > 15);
248
249 return (u2);
250}
251
252/*
253 * Timecounter freqency adjustment interface.
254 */
255static int
256acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
257{
258 int error;
259 u_int freq;
260
261 if (acpi_timer_timecounter.tc_frequency == 0)
262 return (EOPNOTSUPP);
263 freq = acpi_timer_frequency;
264 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
265 if (error == 0 && req->newptr != NULL) {
266 acpi_timer_frequency = freq;
267 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
268 }
269
270 return (error);
271}
272
273SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
274 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
275
276/*
277 * Test harness for verifying ACPI timer behaviour.
278 * Boot with debug.acpi.timer_test set to invoke this.
279 */
280static void
281acpi_timer_test(void)
282{
283 u_int32_t u1, u2, u3;
284
285 u1 = read_counter();
286 u2 = read_counter();
287 u3 = read_counter();
288
289 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
290 for (;;) {
291 /*
292 * The failure case is where u3 > u1, but u2 does not fall between
293 * the two, ie. it contains garbage.
294 */
295 if (u3 > u1) {
296 if (u2 < u1 || u2 > u3)
297 device_printf(acpi_timer_dev,
298 "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
299 u1, u2, u3);
300 }
301 u1 = u2;
302 u2 = u3;
303 u3 = read_counter();
304 }
305}
306
307/*
308 * Chipset workaround driver hung off PCI.
309 *
310 * Some ACPI timers are known or believed to suffer from implementation
311 * problems which can lead to erroneous values being read from the timer.
312 *
313 * Since we can't trust unknown chipsets, we default to a timer-read
314 * routine which compensates for the most common problem (as detailed
315 * in the excerpt from the Intel PIIX4 datasheet below).
316 *
317 * When we detect a known-functional chipset, we disable the workaround
318 * to improve speed.
319 *
320 * ] 20. ACPI Timer Errata
321 * ]
322 * ] Problem: The power management timer may return improper result when
323 * ] read. Although the timer value settles properly after incrementing,
324 * ] while incrementing there is a 3nS window every 69.8nS where the
325 * ] timer value is indeterminate (a 4.2% chance that the data will be
326 * ] incorrect when read). As a result, the ACPI free running count up
327 * ] timer specification is violated due to erroneous reads. Implication:
328 * ] System hangs due to the "inaccuracy" of the timer when used by
329 * ] software for time critical events and delays.
330 * ]
331 * ] Workaround: Read the register twice and compare.
332 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
333 * ] in the PIIX4M.
334 *
335 * The counter is in other words not latched to the PCI bus clock when
336 * read. Notice the workaround isn't: We need to read until we have
337 * three monotonic samples and then use the middle one, otherwise we are
338 * not protected against the fact that the bits can be wrong in two
339 * directions. If we only cared about monosity two reads would be enough.
340 */
341
342#if 0
343static int acpi_timer_pci_probe(device_t dev);
344
345static device_method_t acpi_timer_pci_methods[] = {
346 DEVMETHOD(device_probe, acpi_timer_pci_probe),
347 {0, 0}
348};
349
350static driver_t acpi_timer_pci_driver = {
351 "acpi_timer_pci",
352 acpi_timer_pci_methods,
353 0,
354};
355
356devclass_t acpi_timer_pci_devclass;
357DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver,
358 acpi_timer_pci_devclass, 0, 0);
359
360/*
361 * Look at PCI devices going past; if we detect one we know contains
362 * a functional ACPI timer device, enable the faster timecounter read
363 * routine.
364 */
365static int
366acpi_timer_pci_probe(device_t dev)
367{
368 int vendor, device, revid;
369
370 vendor = pci_get_vendor(dev);
371 device = pci_get_device(dev);
372 revid = pci_get_revid(dev);
373
374 /* Detect the PIIX4M and i440MX, respectively */
375 if ((vendor == 0x8086 && device == 0x7113 && revid >= 0x03) ||
376 (vendor == 0x8086 && device == 0x719b)) {
377
378 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
379 acpi_timer_timecounter.tc_name = "ACPI-fast";
380 if (bootverbose) {
381 device_printf(acpi_timer_dev,"functional ACPI timer detected, "
382 "enabling fast timecount interface\n");
383 }
384 }
385
386 /* We never match anything */
387 return (ENXIO);
388}
389#endif
| 56ACPI_MODULE_NAME("TIMER")
57
58static device_t acpi_timer_dev;
59struct resource *acpi_timer_reg;
60
61static u_int acpi_timer_frequency = 14318182 / 4;
62
63static void acpi_timer_identify(driver_t *driver, device_t parent);
64static int acpi_timer_probe(device_t dev);
65static int acpi_timer_attach(device_t dev);
66static unsigned acpi_timer_get_timecount(struct timecounter *tc);
67static unsigned acpi_timer_get_timecount_safe(struct timecounter *tc);
68static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
69static void acpi_timer_test(void);
70
71static uint32_t read_counter(void);
72static int test_counter(void);
73
74static device_method_t acpi_timer_methods[] = {
75 DEVMETHOD(device_identify, acpi_timer_identify),
76 DEVMETHOD(device_probe, acpi_timer_probe),
77 DEVMETHOD(device_attach, acpi_timer_attach),
78
79 {0, 0}
80};
81
82static driver_t acpi_timer_driver = {
83 "acpi_timer",
84 acpi_timer_methods,
85 0,
86};
87
88static devclass_t acpi_timer_devclass;
89DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
90
91static struct timecounter acpi_timer_timecounter = {
92 acpi_timer_get_timecount_safe,
93 0,
94 0xffffff,
95 0,
96 "ACPI",
97 1000
98};
99
100static uint32_t
101read_counter()
102{
103 bus_space_handle_t bsh;
104 bus_space_tag_t bst;
105 u_int32_t tv;
106
107 bsh = rman_get_bushandle(acpi_timer_reg);
108 bst = rman_get_bustag(acpi_timer_reg);
109 tv = bus_space_read_4(bst, bsh, 0);
110 bus_space_barrier(bst, bsh, 0, 4, BUS_SPACE_BARRIER_READ);
111
112 return (tv);
113}
114
115#define N 2000
116static int
117test_counter()
118{
119 u_int last, this;
120 int min, max, n, delta;
121
122 min = 10000000;
123 max = 0;
124 last = read_counter();
125 for (n = 0; n < N; n++) {
126 this = read_counter();
127 delta = (this - last) & 0xffffff;
128 if (delta > max)
129 max = delta;
130 else if (delta < min)
131 min = delta;
132 last = this;
133 }
134 if (max - min > 2)
135 n = 0;
136 else if (min < 0 || max == 0)
137 n = 0;
138 else
139 n = 1;
140 if (bootverbose) {
141 printf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
142 n ? "GOOD" : "BAD ",
143 min, max, max - min);
144 }
145
146 return (n);
147}
148#undef N
149
150/*
151 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
152 * we will be using.
153 */
154static void
155acpi_timer_identify(driver_t *driver, device_t parent)
156{
157 device_t dev;
158 char desc[40];
159 u_long rlen, rstart;
160 int i, j, rid, rtype;
161
162 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
163
164 if (acpi_disabled("timer") || AcpiGbl_FADT == NULL)
165 return_VOID;
166
167 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) {
168 device_printf(parent, "could not add acpi_timer0\n");
169 return_VOID;
170 }
171 acpi_timer_dev = dev;
172
173 rid = 0;
174 rlen = AcpiGbl_FADT->PmTmLen;
175 rtype = (AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId)
176 ? SYS_RES_IOPORT : SYS_RES_MEMORY;
177 rstart = AcpiGbl_FADT->XPmTmrBlk.Address;
178 bus_set_resource(dev, rtype, rid, rstart, rlen);
179 acpi_timer_reg = bus_alloc_resource(dev, rtype, &rid, 0, ~0, 1, RF_ACTIVE);
180 if (acpi_timer_reg == NULL) {
181 device_printf(dev, "couldn't allocate I/O resource (%s 0x%lx)\n",
182 rtype == SYS_RES_IOPORT ? "port" : "mem", rstart);
183 return_VOID;
184 }
185 if (testenv("debug.acpi.timer_test"))
186 acpi_timer_test();
187
188 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
189 j = 0;
190 for(i = 0; i < 10; i++)
191 j += test_counter();
192 if (j == 10) {
193 acpi_timer_timecounter.tc_name = "ACPI-fast";
194 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
195 } else {
196 acpi_timer_timecounter.tc_name = "ACPI-safe";
197 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
198 }
199 tc_init(&acpi_timer_timecounter);
200
201 sprintf(desc, "%d-bit timer at 3.579545MHz",
202 AcpiGbl_FADT->TmrValExt ? 32 : 24);
203 device_set_desc_copy(dev, desc);
204
205 return_VOID;
206}
207
208static int
209acpi_timer_probe(device_t dev)
210{
211 if (dev == acpi_timer_dev)
212 return (0);
213
214 return (ENXIO);
215}
216
217static int
218acpi_timer_attach(device_t dev)
219{
220 return (0);
221}
222
223/*
224 * Fetch current time value from reliable hardware.
225 */
226static unsigned
227acpi_timer_get_timecount(struct timecounter *tc)
228{
229 return (read_counter());
230}
231
232/*
233 * Fetch current time value from hardware that may not correctly
234 * latch the counter.
235 */
236static unsigned
237acpi_timer_get_timecount_safe(struct timecounter *tc)
238{
239 unsigned u1, u2, u3;
240
241 u2 = read_counter();
242 u3 = read_counter();
243 do {
244 u1 = u2;
245 u2 = u3;
246 u3 = read_counter();
247 } while (u1 > u2 || u2 > u3 || u3 - u1 > 15);
248
249 return (u2);
250}
251
252/*
253 * Timecounter freqency adjustment interface.
254 */
255static int
256acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
257{
258 int error;
259 u_int freq;
260
261 if (acpi_timer_timecounter.tc_frequency == 0)
262 return (EOPNOTSUPP);
263 freq = acpi_timer_frequency;
264 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
265 if (error == 0 && req->newptr != NULL) {
266 acpi_timer_frequency = freq;
267 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
268 }
269
270 return (error);
271}
272
273SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
274 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
275
276/*
277 * Test harness for verifying ACPI timer behaviour.
278 * Boot with debug.acpi.timer_test set to invoke this.
279 */
280static void
281acpi_timer_test(void)
282{
283 u_int32_t u1, u2, u3;
284
285 u1 = read_counter();
286 u2 = read_counter();
287 u3 = read_counter();
288
289 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
290 for (;;) {
291 /*
292 * The failure case is where u3 > u1, but u2 does not fall between
293 * the two, ie. it contains garbage.
294 */
295 if (u3 > u1) {
296 if (u2 < u1 || u2 > u3)
297 device_printf(acpi_timer_dev,
298 "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
299 u1, u2, u3);
300 }
301 u1 = u2;
302 u2 = u3;
303 u3 = read_counter();
304 }
305}
306
307/*
308 * Chipset workaround driver hung off PCI.
309 *
310 * Some ACPI timers are known or believed to suffer from implementation
311 * problems which can lead to erroneous values being read from the timer.
312 *
313 * Since we can't trust unknown chipsets, we default to a timer-read
314 * routine which compensates for the most common problem (as detailed
315 * in the excerpt from the Intel PIIX4 datasheet below).
316 *
317 * When we detect a known-functional chipset, we disable the workaround
318 * to improve speed.
319 *
320 * ] 20. ACPI Timer Errata
321 * ]
322 * ] Problem: The power management timer may return improper result when
323 * ] read. Although the timer value settles properly after incrementing,
324 * ] while incrementing there is a 3nS window every 69.8nS where the
325 * ] timer value is indeterminate (a 4.2% chance that the data will be
326 * ] incorrect when read). As a result, the ACPI free running count up
327 * ] timer specification is violated due to erroneous reads. Implication:
328 * ] System hangs due to the "inaccuracy" of the timer when used by
329 * ] software for time critical events and delays.
330 * ]
331 * ] Workaround: Read the register twice and compare.
332 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
333 * ] in the PIIX4M.
334 *
335 * The counter is in other words not latched to the PCI bus clock when
336 * read. Notice the workaround isn't: We need to read until we have
337 * three monotonic samples and then use the middle one, otherwise we are
338 * not protected against the fact that the bits can be wrong in two
339 * directions. If we only cared about monosity two reads would be enough.
340 */
341
342#if 0
343static int acpi_timer_pci_probe(device_t dev);
344
345static device_method_t acpi_timer_pci_methods[] = {
346 DEVMETHOD(device_probe, acpi_timer_pci_probe),
347 {0, 0}
348};
349
350static driver_t acpi_timer_pci_driver = {
351 "acpi_timer_pci",
352 acpi_timer_pci_methods,
353 0,
354};
355
356devclass_t acpi_timer_pci_devclass;
357DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver,
358 acpi_timer_pci_devclass, 0, 0);
359
360/*
361 * Look at PCI devices going past; if we detect one we know contains
362 * a functional ACPI timer device, enable the faster timecounter read
363 * routine.
364 */
365static int
366acpi_timer_pci_probe(device_t dev)
367{
368 int vendor, device, revid;
369
370 vendor = pci_get_vendor(dev);
371 device = pci_get_device(dev);
372 revid = pci_get_revid(dev);
373
374 /* Detect the PIIX4M and i440MX, respectively */
375 if ((vendor == 0x8086 && device == 0x7113 && revid >= 0x03) ||
376 (vendor == 0x8086 && device == 0x719b)) {
377
378 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
379 acpi_timer_timecounter.tc_name = "ACPI-fast";
380 if (bootverbose) {
381 device_printf(acpi_timer_dev,"functional ACPI timer detected, "
382 "enabling fast timecount interface\n");
383 }
384 }
385
386 /* We never match anything */
387 return (ENXIO);
388}
389#endif
|