acpi_timer.c revision 114277
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 114277 2003-04-30 05:27:01Z marcel $ 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 59ACPI_MODULE_NAME("TIMER") 60 61static device_t acpi_timer_dev; 62struct resource *acpi_timer_reg; 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); 71static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS); 72static void acpi_timer_test(void); 73 74static u_int32_t read_counter(void); 75static int test_counter(void); 76 77/* 78 * Driver hung off ACPI. 79 */ 80static 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 88static driver_t acpi_timer_driver = { 89 "acpi_timer", 90 acpi_timer_methods, 91 0, 92}; 93 94static devclass_t acpi_timer_devclass; 95DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0); 96 97/* 98 * Timecounter. 99 */ 100static struct timecounter acpi_timer_timecounter = { 101 acpi_timer_get_timecount_safe, 102 0, 103 0xffffff, 104 0, 105 "ACPI" 106}; 107 108 109static u_int32_t 110read_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 124static int 125test_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 */ 159static void 160acpi_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 216static int 217acpi_timer_probe(device_t dev) 218{ 219 if (dev == acpi_timer_dev) 220 return(0); 221 return(ENXIO); 222} 223 224static int 225acpi_timer_attach(device_t dev) 226{ 227 return(0); 228} 229 230/* 231 * Fetch current time value from reliable hardware. 232 */ 233static unsigned 234acpi_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 */ 243static unsigned 244acpi_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 */ 261static int 262acpi_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 278SYSCTL_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 */ 285static void 286acpi_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 347static int acpi_timer_pci_probe(device_t dev); 348 349static device_method_t acpi_timer_pci_methods[] = { 350 DEVMETHOD(device_probe, acpi_timer_pci_probe), 351 {0, 0} 352}; 353 354static driver_t acpi_timer_pci_driver = { 355 "acpi_timer_pci", 356 acpi_timer_pci_methods, 357 0, 358}; 359 360devclass_t acpi_timer_pci_devclass; 361DRIVER_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 */ 368static int 369acpi_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 390