acpi_timer.c revision 132527
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: head/sys/dev/acpica/acpi_timer.c 132527 2004-07-22 05:32:56Z njl $ 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/timetc.h> 36 37#include <machine/bus.h> 38#include <machine/resource.h> 39#include <sys/rman.h> 40 41#include "acpi.h" 42#include <dev/acpica/acpivar.h> 43#include <dev/pci/pcivar.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 53ACPI_MODULE_NAME("TIMER") 54 55static device_t acpi_timer_dev; 56static struct resource *acpi_timer_reg; 57static bus_space_handle_t acpi_timer_bsh; 58static bus_space_tag_t acpi_timer_bst; 59 60static u_int acpi_timer_frequency = 14318182 / 4; 61 62static void acpi_timer_identify(driver_t *driver, device_t parent); 63static int acpi_timer_probe(device_t dev); 64static int acpi_timer_attach(device_t dev); 65static u_int acpi_timer_get_timecount(struct timecounter *tc); 66static u_int acpi_timer_get_timecount_safe(struct timecounter *tc); 67static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS); 68static void acpi_timer_boot_test(void); 69 70static u_int acpi_timer_read(void); 71static int acpi_timer_test(void); 72 73static device_method_t acpi_timer_methods[] = { 74 DEVMETHOD(device_identify, acpi_timer_identify), 75 DEVMETHOD(device_probe, acpi_timer_probe), 76 DEVMETHOD(device_attach, acpi_timer_attach), 77 78 {0, 0} 79}; 80 81static driver_t acpi_timer_driver = { 82 "acpi_timer", 83 acpi_timer_methods, 84 0, 85}; 86 87static devclass_t acpi_timer_devclass; 88DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0); 89MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1); 90 91static struct timecounter acpi_timer_timecounter = { 92 acpi_timer_get_timecount_safe, /* get_timecount function */ 93 0, /* no poll_pps */ 94 0, /* no default counter_mask */ 95 0, /* no default frequency */ 96 "ACPI", /* name */ 97 1000 /* quality */ 98}; 99 100static u_int 101acpi_timer_read() 102{ 103 return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0)); 104} 105 106/* 107 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources 108 * we will be using. 109 */ 110static void 111acpi_timer_identify(driver_t *driver, device_t parent) 112{ 113 device_t dev; 114 u_long rlen, rstart; 115 int rid, rtype; 116 117 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 118 119 if (acpi_disabled("timer") || AcpiGbl_FADT == NULL || acpi_timer_dev) 120 return_VOID; 121 122 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) { 123 device_printf(parent, "could not add acpi_timer0\n"); 124 return_VOID; 125 } 126 acpi_timer_dev = dev; 127 128 rid = 0; 129 rtype = AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId ? 130 SYS_RES_IOPORT : SYS_RES_MEMORY; 131 rlen = AcpiGbl_FADT->PmTmLen; 132 rstart = AcpiGbl_FADT->XPmTmrBlk.Address; 133 if (bus_set_resource(dev, rtype, rid, rstart, rlen)) 134 device_printf(dev, "couldn't set resource (%s 0x%lx+0x%lx)\n", 135 (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen); 136 return_VOID; 137} 138 139static int 140acpi_timer_probe(device_t dev) 141{ 142 char desc[40]; 143 int i, j, rid, rtype; 144 145 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 146 147 if (dev != acpi_timer_dev) 148 return (ENXIO); 149 150 rid = 0; 151 rtype = AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId ? 152 SYS_RES_IOPORT : SYS_RES_MEMORY; 153 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE); 154 if (acpi_timer_reg == NULL) { 155 device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n", 156 (rtype == SYS_RES_IOPORT) ? "port" : "mem", 157 (u_long)AcpiGbl_FADT->XPmTmrBlk.Address); 158 return (ENXIO); 159 } 160 if (AcpiGbl_FADT->TmrValExt != 0) 161 acpi_timer_timecounter.tc_counter_mask = 0xffffffff; 162 else 163 acpi_timer_timecounter.tc_counter_mask = 0x00ffffff; 164 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 165 if (testenv("debug.acpi.timer_test")) 166 acpi_timer_boot_test(); 167 168 /* 169 * If all tests of the counter succeed, use the ACPI-fast method. If 170 * at least one failed, default to using the safe routine, which reads 171 * the timer multiple times to get a consistent value before returning. 172 */ 173 j = 0; 174 for (i = 0; i < 10; i++) 175 j += acpi_timer_test(); 176 if (j == 10) { 177 acpi_timer_timecounter.tc_name = "ACPI-fast"; 178 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount; 179 } else { 180 acpi_timer_timecounter.tc_name = "ACPI-safe"; 181 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe; 182 } 183 tc_init(&acpi_timer_timecounter); 184 185 sprintf(desc, "%d-bit timer at 3.579545MHz", 186 AcpiGbl_FADT->TmrValExt ? 32 : 24); 187 device_set_desc_copy(dev, desc); 188 189 /* Release the resource, we'll allocate it again during attach. */ 190 bus_release_resource(dev, rtype, rid, acpi_timer_reg); 191 return (0); 192} 193 194static int 195acpi_timer_attach(device_t dev) 196{ 197 int rid, rtype; 198 199 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 200 201 rid = 0; 202 rtype = AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId ? 203 SYS_RES_IOPORT : SYS_RES_MEMORY; 204 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE); 205 if (acpi_timer_reg == NULL) 206 return (ENXIO); 207 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg); 208 acpi_timer_bst = rman_get_bustag(acpi_timer_reg); 209 return (0); 210} 211 212/* 213 * Fetch current time value from reliable hardware. 214 */ 215static u_int 216acpi_timer_get_timecount(struct timecounter *tc) 217{ 218 return (acpi_timer_read()); 219} 220 221/* 222 * Fetch current time value from hardware that may not correctly 223 * latch the counter. We need to read until we have three monotonic 224 * samples and then use the middle one, otherwise we are not protected 225 * against the fact that the bits can be wrong in two directions. If 226 * we only cared about monosity, two reads would be enough. 227 */ 228static u_int 229acpi_timer_get_timecount_safe(struct timecounter *tc) 230{ 231 u_int u1, u2, u3; 232 233 u2 = acpi_timer_read(); 234 u3 = acpi_timer_read(); 235 do { 236 u1 = u2; 237 u2 = u3; 238 u3 = acpi_timer_read(); 239 } while (u1 > u2 || u2 > u3); 240 241 return (u2); 242} 243 244/* 245 * Timecounter freqency adjustment interface. 246 */ 247static int 248acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS) 249{ 250 int error; 251 u_int freq; 252 253 if (acpi_timer_timecounter.tc_frequency == 0) 254 return (EOPNOTSUPP); 255 freq = acpi_timer_frequency; 256 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req); 257 if (error == 0 && req->newptr != NULL) { 258 acpi_timer_frequency = freq; 259 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 260 } 261 262 return (error); 263} 264 265SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW, 266 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", ""); 267 268/* 269 * Some ACPI timers are known or believed to suffer from implementation 270 * problems which can lead to erroneous values being read. This function 271 * tests for consistent results from the timer and returns 1 if it believes 272 * the timer is consistent, otherwise it returns 0. 273 * 274 * It appears the cause is that the counter is not latched to the PCI bus 275 * clock when read: 276 * 277 * ] 20. ACPI Timer Errata 278 * ] 279 * ] Problem: The power management timer may return improper result when 280 * ] read. Although the timer value settles properly after incrementing, 281 * ] while incrementing there is a 3nS window every 69.8nS where the 282 * ] timer value is indeterminate (a 4.2% chance that the data will be 283 * ] incorrect when read). As a result, the ACPI free running count up 284 * ] timer specification is violated due to erroneous reads. Implication: 285 * ] System hangs due to the "inaccuracy" of the timer when used by 286 * ] software for time critical events and delays. 287 * ] 288 * ] Workaround: Read the register twice and compare. 289 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed 290 * ] in the PIIX4M. 291 */ 292#define N 2000 293static int 294acpi_timer_test() 295{ 296 uint32_t last, this; 297 int min, max, n, delta; 298 register_t s; 299 300 min = 10000000; 301 max = 0; 302 303 /* Test the timer with interrupts disabled to get accurate results. */ 304 s = intr_disable(); 305 last = acpi_timer_read(); 306 for (n = 0; n < N; n++) { 307 this = acpi_timer_read(); 308 delta = acpi_TimerDelta(this, last); 309 if (delta > max) 310 max = delta; 311 else if (delta < min) 312 min = delta; 313 last = this; 314 } 315 intr_restore(s); 316 317 if (max - min > 2) 318 n = 0; 319 else if (min < 0 || max == 0) 320 n = 0; 321 else 322 n = 1; 323 if (bootverbose) { 324 printf("ACPI timer looks %s min = %d, max = %d, width = %d\n", 325 n ? "GOOD" : "BAD ", 326 min, max, max - min); 327 } 328 329 return (n); 330} 331#undef N 332 333/* 334 * Test harness for verifying ACPI timer behaviour. 335 * Boot with debug.acpi.timer_test set to invoke this. 336 */ 337static void 338acpi_timer_boot_test(void) 339{ 340 uint32_t u1, u2, u3; 341 342 u1 = acpi_timer_read(); 343 u2 = acpi_timer_read(); 344 u3 = acpi_timer_read(); 345 346 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n"); 347 for (;;) { 348 /* 349 * The failure case is where u3 > u1, but u2 does not fall between 350 * the two, ie. it contains garbage. 351 */ 352 if (u3 > u1) { 353 if (u2 < u1 || u2 > u3) 354 device_printf(acpi_timer_dev, 355 "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n", 356 u1, u2, u3); 357 } 358 u1 = u2; 359 u2 = u3; 360 u3 = acpi_timer_read(); 361 } 362} 363