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: src/sys/dev/acpica/acpi_timer.c,v 1.35 2004/07/22 05:42:14 njl Exp $ 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/systimer.h> 36 #include <sys/rman.h> 37 38 #include <machine/lock.h> 39 #include <bus/pci/pcivar.h> 40 41 #include "acpi.h" 42 #include "accommon.h" 43 #include "acpivar.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 static sysclock_t acpi_counter_mask; 60 static sysclock_t acpi_last_counter; 61 62 #define ACPI_TIMER_FREQ (14318182 / 4) 63 64 static sysclock_t acpi_timer_get_timecount(void); 65 static sysclock_t acpi_timer_get_timecount24(void); 66 static sysclock_t acpi_timer_get_timecount_safe(void); 67 static void acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock); 68 69 static struct cputimer acpi_cputimer = { 70 SLIST_ENTRY_INITIALIZER, 71 "ACPI", 72 CPUTIMER_PRI_ACPI, 73 CPUTIMER_ACPI, 74 acpi_timer_get_timecount_safe, 75 cputimer_default_fromhz, 76 cputimer_default_fromus, 77 acpi_timer_construct, 78 cputimer_default_destruct, 79 ACPI_TIMER_FREQ, 80 0, 0, 0 81 }; 82 83 static int acpi_timer_identify(driver_t *driver, device_t parent); 84 static int acpi_timer_probe(device_t dev); 85 static int acpi_timer_attach(device_t dev); 86 static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS); 87 88 static int acpi_timer_test(void); 89 90 static device_method_t acpi_timer_methods[] = { 91 DEVMETHOD(device_identify, acpi_timer_identify), 92 DEVMETHOD(device_probe, acpi_timer_probe), 93 DEVMETHOD(device_attach, acpi_timer_attach), 94 95 DEVMETHOD_END 96 }; 97 98 static driver_t acpi_timer_driver = { 99 "acpi_timer", 100 acpi_timer_methods, 101 0, 102 }; 103 104 static devclass_t acpi_timer_devclass; 105 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, NULL, NULL); 106 MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1); 107 108 static u_int 109 acpi_timer_read(void) 110 { 111 return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0)); 112 } 113 114 /* 115 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources 116 * we will be using. 117 */ 118 static int 119 acpi_timer_identify(driver_t *driver, device_t parent) 120 { 121 device_t dev; 122 u_long rlen, rstart; 123 int rid, rtype; 124 125 /* 126 * Just try once, do nothing if the 'acpi' bus is rescanned. 127 */ 128 if (device_get_state(parent) == DS_ATTACHED) 129 return (0); 130 131 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 132 133 if (acpi_disabled("timer") || (acpi_quirks & ACPI_Q_TIMER) || 134 acpi_timer_dev) 135 return (ENXIO); 136 137 if ((dev = BUS_ADD_CHILD(parent, parent, 0, "acpi_timer", 0)) == NULL) { 138 device_printf(parent, "could not add acpi_timer0\n"); 139 return (ENXIO); 140 } 141 acpi_timer_dev = dev; 142 143 switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) { 144 case ACPI_ADR_SPACE_SYSTEM_MEMORY: 145 rtype = SYS_RES_MEMORY; 146 break; 147 case ACPI_ADR_SPACE_SYSTEM_IO: 148 rtype = SYS_RES_IOPORT; 149 break; 150 default: 151 return (ENXIO); 152 } 153 rid = 0; 154 rlen = AcpiGbl_FADT.PmTimerLength; 155 rstart = AcpiGbl_FADT.XPmTimerBlock.Address; 156 if (bus_set_resource(dev, rtype, rid, rstart, rlen, -1)) { 157 device_printf(dev, "couldn't set resource (%s 0x%lx+0x%lx)\n", 158 (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen); 159 return (ENXIO); 160 } 161 return (0); 162 } 163 164 static int 165 acpi_timer_probe(device_t dev) 166 { 167 char desc[40]; 168 int i, j, rid, rtype; 169 170 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 171 172 if (dev != acpi_timer_dev) 173 return (ENXIO); 174 175 switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) { 176 case ACPI_ADR_SPACE_SYSTEM_MEMORY: 177 rtype = SYS_RES_MEMORY; 178 break; 179 case ACPI_ADR_SPACE_SYSTEM_IO: 180 rtype = SYS_RES_IOPORT; 181 break; 182 default: 183 return (ENXIO); 184 } 185 rid = 0; 186 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE); 187 if (acpi_timer_reg == NULL) { 188 device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n", 189 (rtype == SYS_RES_IOPORT) ? "port" : "mem", 190 (u_long)AcpiGbl_FADT.XPmTimerBlock.Address); 191 return (ENXIO); 192 } 193 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg); 194 acpi_timer_bst = rman_get_bustag(acpi_timer_reg); 195 if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) != 0) 196 acpi_counter_mask = 0xffffffff; 197 else 198 acpi_counter_mask = 0x00ffffff; 199 200 /* 201 * If all tests of the counter succeed, use the ACPI-fast method. If 202 * at least one failed, default to using the safe routine, which reads 203 * the timer multiple times to get a consistent value before returning. 204 */ 205 j = 0; 206 for (i = 0; i < 10; i++) 207 j += acpi_timer_test(); 208 if (j == 10) { 209 if (acpi_counter_mask == 0xffffffff) { 210 acpi_cputimer.name = "ACPI-fast"; 211 acpi_cputimer.count = acpi_timer_get_timecount; 212 } else { 213 acpi_cputimer.name = "ACPI-fast24"; 214 acpi_cputimer.count = acpi_timer_get_timecount24; 215 } 216 } else { 217 if (acpi_counter_mask == 0xffffffff) 218 acpi_cputimer.name = "ACPI-safe"; 219 else 220 acpi_cputimer.name = "ACPI-safe24"; 221 acpi_cputimer.count = acpi_timer_get_timecount_safe; 222 } 223 224 ksprintf(desc, "%d-bit timer at 3.579545MHz", 225 (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) ? 32 : 24); 226 device_set_desc_copy(dev, desc); 227 228 cputimer_register(&acpi_cputimer); 229 cputimer_select(&acpi_cputimer, 0); 230 /* Release the resource, we'll allocate it again during attach. */ 231 bus_release_resource(dev, rtype, rid, acpi_timer_reg); 232 return (0); 233 } 234 235 static int 236 acpi_timer_attach(device_t dev) 237 { 238 int rid, rtype; 239 240 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 241 242 switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) { 243 case ACPI_ADR_SPACE_SYSTEM_MEMORY: 244 rtype = SYS_RES_MEMORY; 245 break; 246 case ACPI_ADR_SPACE_SYSTEM_IO: 247 rtype = SYS_RES_IOPORT; 248 break; 249 default: 250 return (ENXIO); 251 } 252 rid = 0; 253 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE); 254 if (acpi_timer_reg == NULL) 255 return (ENXIO); 256 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg); 257 acpi_timer_bst = rman_get_bustag(acpi_timer_reg); 258 return (0); 259 } 260 261 /* 262 * Construct the timer. Adjust the base so the system clock does not 263 * jump weirdly. 264 */ 265 static void 266 acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock) 267 { 268 timer->base = 0; 269 timer->base = oldclock - acpi_timer_get_timecount_safe(); 270 } 271 272 /* 273 * Fetch current time value from reliable hardware. 274 * 275 * The cputimer interface requires a 32 bit return value. If the ACPI timer 276 * is only 24 bits then we have to keep track of the upper 8 bits on our 277 * own. 278 * 279 * XXX we could probably get away with using a per-cpu field for this and 280 * just use interrupt disablement instead of clock_lock. 281 */ 282 static sysclock_t 283 acpi_timer_get_timecount24(void) 284 { 285 sysclock_t counter; 286 287 clock_lock(); 288 counter = acpi_timer_read(); 289 if (counter < acpi_last_counter) 290 acpi_cputimer.base += 0x01000000; 291 acpi_last_counter = counter; 292 counter += acpi_cputimer.base; 293 clock_unlock(); 294 return (counter); 295 } 296 297 static sysclock_t 298 acpi_timer_get_timecount(void) 299 { 300 return (acpi_timer_read() + acpi_cputimer.base); 301 } 302 303 /* 304 * Fetch current time value from hardware that may not correctly 305 * latch the counter. We need to read until we have three monotonic 306 * samples and then use the middle one, otherwise we are not protected 307 * against the fact that the bits can be wrong in two directions. If 308 * we only cared about monosity, two reads would be enough. 309 */ 310 static sysclock_t 311 acpi_timer_get_timecount_safe(void) 312 { 313 u_int u1, u2, u3; 314 315 if (acpi_counter_mask != 0xffffffff) 316 clock_lock(); 317 318 u2 = acpi_timer_read(); 319 u3 = acpi_timer_read(); 320 do { 321 u1 = u2; 322 u2 = u3; 323 u3 = acpi_timer_read(); 324 } while (u1 > u2 || u2 > u3); 325 326 if (acpi_counter_mask != 0xffffffff) { 327 if (u2 < acpi_last_counter) 328 acpi_cputimer.base += 0x01000000; 329 acpi_last_counter = u2; 330 clock_unlock(); 331 } 332 return (u2 + acpi_cputimer.base); 333 } 334 335 /* 336 * Timecounter freqency adjustment interface. 337 */ 338 static int 339 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS) 340 { 341 int error; 342 u_int freq; 343 344 if (acpi_cputimer.freq == 0) 345 return (EOPNOTSUPP); 346 freq = acpi_cputimer.freq; 347 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req); 348 if (error == 0 && req->newptr != NULL) 349 cputimer_set_frequency(&acpi_cputimer, freq); 350 351 return (error); 352 } 353 354 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW, 355 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "ACPI timer frequency"); 356 357 /* 358 * Some ACPI timers are known or believed to suffer from implementation 359 * problems which can lead to erroneous values being read. This function 360 * tests for consistent results from the timer and returns 1 if it believes 361 * the timer is consistent, otherwise it returns 0. 362 * 363 * It appears the cause is that the counter is not latched to the PCI bus 364 * clock when read: 365 * 366 * ] 20. ACPI Timer Errata 367 * ] 368 * ] Problem: The power management timer may return improper result when 369 * ] read. Although the timer value settles properly after incrementing, 370 * ] while incrementing there is a 3nS window every 69.8nS where the 371 * ] timer value is indeterminate (a 4.2% chance that the data will be 372 * ] incorrect when read). As a result, the ACPI free running count up 373 * ] timer specification is violated due to erroneous reads. Implication: 374 * ] System hangs due to the "inaccuracy" of the timer when used by 375 * ] software for time critical events and delays. 376 * ] 377 * ] Workaround: Read the register twice and compare. 378 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed 379 * ] in the PIIX4M. 380 */ 381 382 static int 383 acpi_timer_test(void) 384 { 385 uint32_t last, this; 386 int min, max, n, delta; 387 register_t s; 388 389 min = 10000000; 390 max = 0; 391 392 /* Test the timer with interrupts disabled to get accurate results. */ 393 #if defined(__i386__) 394 s = read_eflags(); 395 #elif defined(__x86_64__) 396 s = read_rflags(); 397 #else 398 #error "no read_eflags" 399 #endif 400 cpu_disable_intr(); 401 last = acpi_timer_read(); 402 for (n = 0; n < 2000; n++) { 403 this = acpi_timer_read(); 404 delta = acpi_TimerDelta(this, last); 405 if (delta > max) 406 max = delta; 407 else if (delta < min) 408 min = delta; 409 last = this; 410 } 411 #if defined(__i386__) 412 write_eflags(s); 413 #elif defined(__x86_64__) 414 write_rflags(s); 415 #else 416 #error "no read_eflags" 417 #endif 418 419 if (max - min > 2) 420 n = 0; 421 else if (min < 0 || max == 0) 422 n = 0; 423 else 424 n = 1; 425 if (bootverbose) { 426 kprintf("ACPI timer looks %s min = %d, max = %d, width = %d\n", 427 n ? "GOOD" : "BAD ", 428 min, max, max - min); 429 } 430 431 return (n); 432 } 433 434