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 * $FreeBSD$
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.h>
41 #include <machine/resource.h>
42 #include <sys/rman.h>
43
44 #include "acpi.h"
45
46 #include <dev/acpica/acpivar.h>
47 #include <pci/pcivar.h>
48
49 /*
50 * A timecounter based on the free-running ACPI timer.
51 *
52 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
53 */
54
55 /*
56 * Hooks for the ACPI CA debugging infrastructure
57 */
58 #define _COMPONENT ACPI_SYSTEM
59 ACPI_MODULE_NAME("TIMER")
60
61 static device_t acpi_timer_dev;
62 struct resource *acpi_timer_reg;
63
64 static u_int acpi_timer_frequency = 14318182/4;
65
66 static void acpi_timer_identify(driver_t *driver, device_t parent);
67 static int acpi_timer_probe(device_t dev);
68 static int acpi_timer_attach(device_t dev);
69 static unsigned acpi_timer_get_timecount(struct timecounter *tc);
70 static unsigned acpi_timer_get_timecount_safe(struct timecounter *tc);
71 static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
72 static void acpi_timer_test(void);
73
74 static u_int32_t read_counter(void);
75 static int test_counter(void);
76
77 /*
78 * Driver hung off ACPI.
79 */
80 static device_method_t acpi_timer_methods[] = {
81 DEVMETHOD(device_identify, acpi_timer_identify),
82 DEVMETHOD(device_probe, acpi_timer_probe),
83 DEVMETHOD(device_attach, acpi_timer_attach),
84
85 {0, 0}
86 };
87
88 static driver_t acpi_timer_driver = {
89 "acpi_timer",
90 acpi_timer_methods,
91 0,
92 };
93
94 static devclass_t acpi_timer_devclass;
95 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
96
97 /*
98 * Timecounter.
99 */
100 static struct timecounter acpi_timer_timecounter = {
101 acpi_timer_get_timecount_safe,
102 0,
103 0xffffff,
104 0,
105 "ACPI"
106 };
107
108
109 static u_int32_t
110 read_counter()
111 {
112 bus_space_handle_t bsh;
113 bus_space_tag_t bst;
114 u_int32_t tv;
115
116 bsh = rman_get_bushandle(acpi_timer_reg);
117 bst = rman_get_bustag(acpi_timer_reg);
118 tv = bus_space_read_4(bst, bsh, 0);
119 bus_space_barrier(bst, bsh, 0, 4, BUS_SPACE_BARRIER_READ);
120 return (tv);
121 }
122
123 #define N 2000
124 static int
125 test_counter()
126 {
127 int min, max, n, delta;
128 unsigned last, this;
129
130 min = 10000000;
131 max = 0;
132 last = read_counter();
133 for (n = 0; n < N; n++) {
134 this = read_counter();
135 delta = (this - last) & 0xffffff;
136 if (delta > max)
137 max = delta;
138 else if (delta < min)
139 min = delta;
140 last = this;
141 }
142 if (max - min > 2)
143 n = 0;
144 else if (min < 0 || max == 0)
145 n = 0;
146 else
147 n = 1;
148 if (bootverbose)
149 printf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
150 n ? "GOOD" : "BAD ",
151 min, max, max - min);
152 return (n);
153 }
154
155 /*
156 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
157 * we will be using.
158 */
159 static void
160 acpi_timer_identify(driver_t *driver, device_t parent)
161 {
162 device_t dev;
163 char desc[40];
164 u_long rlen, rstart;
165 int i, j, rid, rtype;
166
167 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
168
169 if (acpi_disabled("timer"))
170 return_VOID;
171
172 if (AcpiGbl_FADT == NULL)
173 return_VOID;
174
175 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) {
176 device_printf(parent, "could not add acpi_timer0\n");
177 return_VOID;
178 }
179 acpi_timer_dev = dev;
180
181 rid = 0;
182 rlen = AcpiGbl_FADT->PmTmLen;
183 rtype = (AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId)
184 ? SYS_RES_IOPORT : SYS_RES_MEMORY;
185 rstart = AcpiGbl_FADT->XPmTmrBlk.Address;
186 bus_set_resource(dev, rtype, rid, rstart, rlen);
187 acpi_timer_reg = bus_alloc_resource(dev, rtype, &rid, 0, ~0, 1, RF_ACTIVE);
188 if (acpi_timer_reg == NULL) {
189 device_printf(dev, "couldn't allocate I/O resource (%s 0x%lx)\n",
190 (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart);
191 return_VOID;
192 }
193 if (testenv("debug.acpi.timer_test"))
194 acpi_timer_test();
195
196 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
197 j = 0;
198 for(i = 0; i < 10; i++)
199 j += test_counter();
200 if (j == 10) {
201 acpi_timer_timecounter.tc_name = "ACPI-fast";
202 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
203 } else {
204 acpi_timer_timecounter.tc_name = "ACPI-safe";
205 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
206 }
207 tc_init(&acpi_timer_timecounter);
208
209 sprintf(desc, "%d-bit timer at 3.579545MHz", (AcpiGbl_FADT->TmrValExt)
210 ? 32 : 24);
211 device_set_desc_copy(dev, desc);
212
213 return_VOID;
214 }
215
216 static int
217 acpi_timer_probe(device_t dev)
218 {
219 if (dev == acpi_timer_dev)
220 return(0);
221 return(ENXIO);
222 }
223
224 static int
225 acpi_timer_attach(device_t dev)
226 {
227 return(0);
228 }
229
230 /*
231 * Fetch current time value from reliable hardware.
232 */
233 static unsigned
234 acpi_timer_get_timecount(struct timecounter *tc)
235 {
236 return (read_counter());
237 }
238
239 /*
240 * Fetch current time value from hardware that may not correctly
241 * latch the counter.
242 */
243 static unsigned
244 acpi_timer_get_timecount_safe(struct timecounter *tc)
245 {
246 unsigned u1, u2, u3;
247
248 u2 = read_counter();
249 u3 = read_counter();
250 do {
251 u1 = u2;
252 u2 = u3;
253 u3 = read_counter();
254 } while (u1 > u2 || u2 > u3 || (u3 - u1) > 15);
255 return (u2);
256 }
257
258 /*
259 * Timecounter freqency adjustment interface.
260 */
261 static int
262 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
263 {
264 int error;
265 u_int freq;
266
267 if (acpi_timer_timecounter.tc_frequency == 0)
268 return (EOPNOTSUPP);
269 freq = acpi_timer_frequency;
270 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
271 if (error == 0 && req->newptr != NULL) {
272 acpi_timer_frequency = freq;
273 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
274 }
275 return (error);
276 }
277
278 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
279 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
280
281 /*
282 * Test harness for verifying ACPI timer behaviour.
283 * Boot with debug.acpi.timer_test set to invoke this.
284 */
285 static void
286 acpi_timer_test(void)
287 {
288 u_int32_t u1, u2, u3;
289
290 u1 = read_counter();
291 u2 = read_counter();
292 u3 = read_counter();
293
294 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
295 for (;;) {
296 /*
297 * The failure case is where u3 > u1, but u2 does not fall between the two,
298 * ie. it contains garbage.
299 */
300 if (u3 > u1) {
301 if ((u2 < u1) || (u2 > u3))
302 device_printf(acpi_timer_dev, "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
303 u1, u2, u3);
304 }
305 u1 = u2;
306 u2 = u3;
307 u3 = read_counter();
308 }
309 }
310
311 /*
312 * Chipset workaround driver hung off PCI.
313 *
314 * Some ACPI timers are known or believed to suffer from implementation
315 * problems which can lead to erroneous values being read from the timer.
316 *
317 * Since we can't trust unknown chipsets, we default to a timer-read
318 * routine which compensates for the most common problem (as detailed
319 * in the excerpt from the Intel PIIX4 datasheet below).
320 *
321 * When we detect a known-functional chipset, we disable the workaround
322 * to improve speed.
323 *
324 * ] 20. ACPI Timer Errata
325 * ]
326 * ] Problem: The power management timer may return improper result when
327 * ] read. Although the timer value settles properly after incrementing,
328 * ] while incrementing there is a 3nS window every 69.8nS where the
329 * ] timer value is indeterminate (a 4.2% chance that the data will be
330 * ] incorrect when read). As a result, the ACPI free running count up
331 * ] timer specification is violated due to erroneous reads. Implication:
332 * ] System hangs due to the "inaccuracy" of the timer when used by
333 * ] software for time critical events and delays.
334 * ]
335 * ] Workaround: Read the register twice and compare.
336 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
337 * ] in the PIIX4M.
338 *
339 * The counter is in other words not latched to the PCI bus clock when
340 * read. Notice the workaround isn't: We need to read until we have
341 * three monotonic samples and then use the middle one, otherwise we are
342 * not protected against the fact that the bits can be wrong in two
343 * directions. If we only cared about monosity two reads would be enough.
344 */
345
346 #if 0
347 static int acpi_timer_pci_probe(device_t dev);
348
349 static device_method_t acpi_timer_pci_methods[] = {
350 DEVMETHOD(device_probe, acpi_timer_pci_probe),
351 {0, 0}
352 };
353
354 static driver_t acpi_timer_pci_driver = {
355 "acpi_timer_pci",
356 acpi_timer_pci_methods,
357 0,
358 };
359
360 devclass_t acpi_timer_pci_devclass;
361 DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver, acpi_timer_pci_devclass, 0, 0);
362
363 /*
364 * Look at PCI devices going past; if we detect one we know contains
365 * a functional ACPI timer device, enable the faster timecounter read
366 * routine.
367 */
368 static int
369 acpi_timer_pci_probe(device_t dev)
370 {
371 int vendor, device, revid;
372
373 vendor = pci_get_vendor(dev);
374 device = pci_get_device(dev);
375 revid = pci_get_revid(dev);
376
377 if (((vendor == 0x8086) && (device == 0x7113) && (revid >= 0x03)) || /* PIIX4M */
378 ((vendor == 0x8086) && (device == 0x719b)) || /* i440MX */
379 0) {
380
381 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
382 acpi_timer_timecounter.tc_name = "ACPI-fast";
383 if (bootverbose)
384 device_printf(acpi_timer_dev, "functional ACPI timer detected, enabling fast timecount interface\n");
385 }
386
387 return(ENXIO); /* we never match anything */
388 }
389 #endif
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