acpi_timer.c (d8a9fe36a1186708ba2285418113fe89a109b5dd) acpi_timer.c (feade9194437a8bddac719ffa4e086a9308e266a)
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:

--- 53 unchanged lines hidden (view full) ---

62 0)
63
64static u_int acpi_timer_frequency = 14318182/4;
65
66static void acpi_timer_identify(driver_t *driver, device_t parent);
67static int acpi_timer_probe(device_t dev);
68static int acpi_timer_attach(device_t dev);
69static unsigned acpi_timer_get_timecount(struct timecounter *tc);
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:

--- 53 unchanged lines hidden (view full) ---

62 0)
63
64static u_int acpi_timer_frequency = 14318182/4;
65
66static void acpi_timer_identify(driver_t *driver, device_t parent);
67static int acpi_timer_probe(device_t dev);
68static int acpi_timer_attach(device_t dev);
69static unsigned acpi_timer_get_timecount(struct timecounter *tc);
70static unsigned acpi_timer_get_timecount_safe(struct timecounter *tc);
70static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
71static void acpi_timer_test(void);
72
73/*
74 * Driver hung off ACPI.
75 */
76static device_method_t acpi_timer_methods[] = {
77 DEVMETHOD(device_identify, acpi_timer_identify),

--- 11 unchanged lines hidden (view full) ---

89
90devclass_t acpi_timer_devclass;
91DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
92
93/*
94 * Timecounter.
95 */
96static struct timecounter acpi_timer_timecounter = {
71static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
72static void acpi_timer_test(void);
73
74/*
75 * Driver hung off ACPI.
76 */
77static device_method_t acpi_timer_methods[] = {
78 DEVMETHOD(device_identify, acpi_timer_identify),

--- 11 unchanged lines hidden (view full) ---

90
91devclass_t acpi_timer_devclass;
92DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
93
94/*
95 * Timecounter.
96 */
97static struct timecounter acpi_timer_timecounter = {
97 acpi_timer_get_timecount,
98 acpi_timer_get_timecount_safe,
98 0,
99 0xffffff,
100 0,
101 "ACPI"
102};
103
104SYSCTL_OPAQUE(_debug, OID_AUTO, acpi_timecounter, CTLFLAG_RD,
105 &acpi_timer_timecounter, sizeof(acpi_timer_timecounter), "S,timecounter", "");

--- 33 unchanged lines hidden (view full) ---

139
140 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
141 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
142 tc_init(&acpi_timer_timecounter);
143
144 sprintf(desc, "%d-bit timer at 3.579545MHz", AcpiGbl_FADT->TmrValExt ? 32 : 24);
145 device_set_desc_copy(dev, desc);
146
99 0,
100 0xffffff,
101 0,
102 "ACPI"
103};
104
105SYSCTL_OPAQUE(_debug, OID_AUTO, acpi_timecounter, CTLFLAG_RD,
106 &acpi_timer_timecounter, sizeof(acpi_timer_timecounter), "S,timecounter", "");

--- 33 unchanged lines hidden (view full) ---

140
141 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
142 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
143 tc_init(&acpi_timer_timecounter);
144
145 sprintf(desc, "%d-bit timer at 3.579545MHz", AcpiGbl_FADT->TmrValExt ? 32 : 24);
146 device_set_desc_copy(dev, desc);
147
148#if 0
149 {
150 u_int64_t first;
151
152 first = rdtsc();
153 acpi_timer_get_timecount(NULL);
154 printf("acpi_timer_get_timecount %lld cycles\n", rdtsc() - first);
155
156 first = rdtsc();
157 acpi_timer_get_timecount_safe(NULL);
158 printf("acpi_timer_get_timecount_safe %lld cycles\n", rdtsc() - first);
159 }
160#endif
161
147 return_VOID;
148}
149
150static int
151acpi_timer_probe(device_t dev)
152{
153 if (dev == acpi_timer_dev)
154 return(0);
155 return(ENXIO);
156}
157
158static int
159acpi_timer_attach(device_t dev)
160{
161 return(0);
162}
163
164/*
162 return_VOID;
163}
164
165static int
166acpi_timer_probe(device_t dev)
167{
168 if (dev == acpi_timer_dev)
169 return(0);
170 return(ENXIO);
171}
172
173static int
174acpi_timer_attach(device_t dev)
175{
176 return(0);
177}
178
179/*
165 * Fetch current time value from hardware.
180 * Fetch current time value from reliable hardware.
166 */
167static unsigned
168acpi_timer_get_timecount(struct timecounter *tc)
169{
170 return(TIMER_READ);
171}
172
173/*
181 */
182static unsigned
183acpi_timer_get_timecount(struct timecounter *tc)
184{
185 return(TIMER_READ);
186}
187
188/*
189 * Fetch current time value from hardware that may not correctly
190 * latch the counter.
191 */
192static unsigned
193acpi_timer_get_timecount_safe(struct timecounter *tc)
194{
195 unsigned u1, u2, u3;
196
197 u2 = TIMER_READ;
198 u3 = TIMER_READ;
199 do {
200 u1 = u2;
201 u2 = u3;
202 u3 = TIMER_READ;
203 } while (u1 > u2 || u2 > u3);
204 return (u2);
205}
206
207/*
174 * Timecounter freqency adjustment interface.
175 */
176static int
177acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
178{
179 int error;
180 u_int freq;
181

--- 40 unchanged lines hidden (view full) ---

222 u2 = u3;
223 u3 = TIMER_READ;
224 }
225}
226
227/*
228 * Chipset workaround driver hung off PCI.
229 *
208 * Timecounter freqency adjustment interface.
209 */
210static int
211acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
212{
213 int error;
214 u_int freq;
215

--- 40 unchanged lines hidden (view full) ---

256 u2 = u3;
257 u3 = TIMER_READ;
258 }
259}
260
261/*
262 * Chipset workaround driver hung off PCI.
263 *
264 * Some ACPI timers are known or believed to suffer from implementation
265 * problems which can lead to erroneous values being read from the timer.
266 *
267 * Since we can't trust unknown chipsets, we default to a timer-read
268 * routine which compensates for the most common problem (as detailed
269 * in the excerpt from the Intel PIIX4 datasheet below).
270 *
271 * When we detect a known-functional chipset, we disable the workaround
272 * to improve speed.
273 *
230 * ] 20. ACPI Timer Errata
231 * ]
232 * ] Problem: The power management timer may return improper result when
233 * ] read. Although the timer value settles properly after incrementing,
234 * ] while incrementing there is a 3nS window every 69.8nS where the
235 * ] timer value is indeterminate (a 4.2% chance that the data will be
236 * ] incorrect when read). As a result, the ACPI free running count up
237 * ] timer specification is violated due to erroneous reads. Implication:

--- 7 unchanged lines hidden (view full) ---

245 * The counter is in other words not latched to the PCI bus clock when
246 * read. Notice the workaround isn't: We need to read until we have
247 * three monotonic samples and then use the middle one, otherwise we are
248 * not protected against the fact that the bits can be wrong in two
249 * directions. If we only cared about monosity two reads would be enough.
250 */
251
252static int acpi_timer_pci_probe(device_t dev);
274 * ] 20. ACPI Timer Errata
275 * ]
276 * ] Problem: The power management timer may return improper result when
277 * ] read. Although the timer value settles properly after incrementing,
278 * ] while incrementing there is a 3nS window every 69.8nS where the
279 * ] timer value is indeterminate (a 4.2% chance that the data will be
280 * ] incorrect when read). As a result, the ACPI free running count up
281 * ] timer specification is violated due to erroneous reads. Implication:

--- 7 unchanged lines hidden (view full) ---

289 * The counter is in other words not latched to the PCI bus clock when
290 * read. Notice the workaround isn't: We need to read until we have
291 * three monotonic samples and then use the middle one, otherwise we are
292 * not protected against the fact that the bits can be wrong in two
293 * directions. If we only cared about monosity two reads would be enough.
294 */
295
296static int acpi_timer_pci_probe(device_t dev);
253static unsigned acpi_timer_get_timecount_piix(struct timecounter *tc);
254
255static device_method_t acpi_timer_pci_methods[] = {
256 DEVMETHOD(device_probe, acpi_timer_pci_probe),
257 {0, 0}
258};
259
260static driver_t acpi_timer_pci_driver = {
261 "acpi_timer_pci",
262 acpi_timer_pci_methods,
263 0,
264};
265
266devclass_t acpi_timer_pci_devclass;
267DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver, acpi_timer_pci_devclass, 0, 0);
268
269/*
297
298static device_method_t acpi_timer_pci_methods[] = {
299 DEVMETHOD(device_probe, acpi_timer_pci_probe),
300 {0, 0}
301};
302
303static driver_t acpi_timer_pci_driver = {
304 "acpi_timer_pci",
305 acpi_timer_pci_methods,
306 0,
307};
308
309devclass_t acpi_timer_pci_devclass;
310DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver, acpi_timer_pci_devclass, 0, 0);
311
312/*
270 * Look at PCI devices as they go past, and if we detect a PIIX4 older than
271 * the PIIX4M, use an alternate get_timecount routine.
272 *
273 * XXX do we know that other timecounters work? Perhaps we should test them?
313 * Look at PCI devices going past; if we detect one we know contains
314 * a functional ACPI timer device, enable the faster timecounter read
315 * routine.
274 */
275static int
276acpi_timer_pci_probe(device_t dev)
277{
278 if ((pci_get_vendor(dev) == 0x8086) &&
279 (pci_get_device(dev) == 0x7113) &&
316 */
317static int
318acpi_timer_pci_probe(device_t dev)
319{
320 if ((pci_get_vendor(dev) == 0x8086) &&
321 (pci_get_device(dev) == 0x7113) &&
280 (pci_get_revid(dev) < 0x03)) {
281 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_piix;
282 acpi_timer_timecounter.tc_name = "ACPI-PIIX";
283 device_printf(acpi_timer_dev, "enabling PIIX4 timer workaround\n");
322 (pci_get_revid(dev) >= 0x03)) {
323 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
324 acpi_timer_timecounter.tc_name = "ACPI-PIIX4M";
325 if (bootverbose)
326 device_printf(acpi_timer_dev, "PIIX4M or later detected, enabling ACPI timer optimisation\n");
284 }
285
286 return(ENXIO); /* we never match anything */
287}
327 }
328
329 return(ENXIO); /* we never match anything */
330}
288
289/*
290 * Read the buggy PIIX4 ACPI timer and compensate for its behaviour.
291 */
292static unsigned
293acpi_timer_get_timecount_piix(struct timecounter *tc)
294{
295 unsigned u1, u2, u3;
296
297 u2 = TIMER_READ;
298 u3 = TIMER_READ;
299 do {
300 u1 = u2;
301 u2 = u3;
302 u3 = TIMER_READ;
303 } while (u1 > u2 || u2 > u3);
304 return (u2);
305}
306