acpi_timer.c revision 105281
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 105281 2002-10-16 17:27:40Z jhb $ 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_pio.h> 41#include <machine/bus.h> 42#include <machine/resource.h> 43#include <sys/rman.h> 44 45#include "acpi.h" 46 47#include <dev/acpica/acpivar.h> 48#include <pci/pcivar.h> 49 50/* 51 * A timecounter based on the free-running ACPI timer. 52 * 53 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>. 54 */ 55 56/* 57 * Hooks for the ACPI CA debugging infrastructure 58 */ 59#define _COMPONENT ACPI_SYSTEM 60ACPI_MODULE_NAME("TIMER") 61 62static device_t acpi_timer_dev; 63struct resource *acpi_timer_reg; 64#define TIMER_READ bus_space_read_4(rman_get_bustag(acpi_timer_reg), \ 65 rman_get_bushandle(acpi_timer_reg), \ 66 0) 67 68static u_int acpi_timer_frequency = 14318182/4; 69 70static void acpi_timer_identify(driver_t *driver, device_t parent); 71static int acpi_timer_probe(device_t dev); 72static int acpi_timer_attach(device_t dev); 73static unsigned acpi_timer_get_timecount(struct timecounter *tc); 74static unsigned acpi_timer_get_timecount_safe(struct timecounter *tc); 75static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS); 76static void acpi_timer_test(void); 77 78/* 79 * Driver hung off ACPI. 80 */ 81static device_method_t acpi_timer_methods[] = { 82 DEVMETHOD(device_identify, acpi_timer_identify), 83 DEVMETHOD(device_probe, acpi_timer_probe), 84 DEVMETHOD(device_attach, acpi_timer_attach), 85 86 {0, 0} 87}; 88 89static driver_t acpi_timer_driver = { 90 "acpi_timer", 91 acpi_timer_methods, 92 0, 93}; 94 95static devclass_t acpi_timer_devclass; 96DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0); 97 98/* 99 * Timecounter. 100 */ 101static struct timecounter acpi_timer_timecounter = { 102 acpi_timer_get_timecount_safe, 103 0, 104 0xffffff, 105 0, 106 "ACPI" 107}; 108 109static int test_counter(void); 110 111#define N 2000 112static int 113test_counter() 114{ 115 int min, max, n, delta; 116 unsigned last, this; 117 118 min = 10000000; 119 max = 0; 120 last = TIMER_READ; 121 for (n = 0; n < N; n++) { 122 this = TIMER_READ; 123 delta = (this - last) & 0xffffff; 124 if (delta > max) 125 max = delta; 126 else if (delta < min) 127 min = delta; 128 last = this; 129 } 130 if (max - min > 2) 131 n = 0; 132 else if (min < 0) 133 n = 0; 134 else 135 n = 1; 136 if (bootverbose) 137 printf("ACPI timer looks %s min = %d, max = %d, width = %d\n", 138 n ? "GOOD" : "BAD ", 139 min, max, max - min + 1); 140 return (n); 141} 142 143/* 144 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources 145 * we will be using. 146 */ 147static void 148acpi_timer_identify(driver_t *driver, device_t parent) 149{ 150 device_t dev; 151 char desc[40]; 152 int rid, i, j; 153 154 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 155 156 if (acpi_disabled("timer")) 157 return_VOID; 158 159 if (AcpiGbl_FADT == NULL) 160 return_VOID; 161 162 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) { 163 device_printf(parent, "could not add acpi_timer0\n"); 164 return_VOID; 165 } 166 acpi_timer_dev = dev; 167 rid = 0; 168 bus_set_resource(dev, SYS_RES_IOPORT, rid, AcpiGbl_FADT->V1_PmTmrBlk, sizeof(u_int32_t)); 169 if ((acpi_timer_reg = bus_alloc_resource(dev, SYS_RES_IOPORT, &rid, 0, ~0, 1, RF_ACTIVE)) == NULL) { 170 device_printf(dev, "couldn't allocate I/O resource (port 0x%x)\n", AcpiGbl_FADT->V1_PmTmrBlk); 171 return_VOID; 172 } 173 if (testenv("debug.acpi.timer_test")) 174 acpi_timer_test(); 175 176 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 177 j = 0; 178 for(i = 0; i < 10; i++) 179 j += test_counter(); 180 if (j == 10) { 181 acpi_timer_timecounter.tc_name = "ACPI-fast"; 182 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount; 183 } else { 184 acpi_timer_timecounter.tc_name = "ACPI-safe"; 185 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe; 186 } 187 tc_init(&acpi_timer_timecounter); 188 189 sprintf(desc, "%d-bit timer at 3.579545MHz", AcpiGbl_FADT->TmrValExt ? 32 : 24); 190 device_set_desc_copy(dev, desc); 191 192 return_VOID; 193} 194 195static int 196acpi_timer_probe(device_t dev) 197{ 198 if (dev == acpi_timer_dev) 199 return(0); 200 return(ENXIO); 201} 202 203static int 204acpi_timer_attach(device_t dev) 205{ 206 return(0); 207} 208 209/* 210 * Fetch current time value from reliable hardware. 211 */ 212static unsigned 213acpi_timer_get_timecount(struct timecounter *tc) 214{ 215 return(TIMER_READ); 216} 217 218/* 219 * Fetch current time value from hardware that may not correctly 220 * latch the counter. 221 */ 222static unsigned 223acpi_timer_get_timecount_safe(struct timecounter *tc) 224{ 225 unsigned u1, u2, u3; 226 227 u2 = TIMER_READ; 228 u3 = TIMER_READ; 229 do { 230 u1 = u2; 231 u2 = u3; 232 u3 = TIMER_READ; 233 } while (u1 > u2 || u2 > u3 || (u3 - u1) > 15); 234 return (u2); 235} 236 237/* 238 * Timecounter freqency adjustment interface. 239 */ 240static int 241acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS) 242{ 243 int error; 244 u_int freq; 245 246 if (acpi_timer_timecounter.tc_frequency == 0) 247 return (EOPNOTSUPP); 248 freq = acpi_timer_frequency; 249 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req); 250 if (error == 0 && req->newptr != NULL) { 251 acpi_timer_frequency = freq; 252 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 253 } 254 return (error); 255} 256 257SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW, 258 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", ""); 259 260/* 261 * Test harness for verifying ACPI timer behaviour. 262 * Boot with debug.acpi.timer_test set to invoke this. 263 */ 264static void 265acpi_timer_test(void) 266{ 267 u_int32_t u1, u2, u3; 268 269 u1 = TIMER_READ; 270 u2 = TIMER_READ; 271 u3 = TIMER_READ; 272 273 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n"); 274 for (;;) { 275 /* 276 * The failure case is where u3 > u1, but u2 does not fall between the two, 277 * ie. it contains garbage. 278 */ 279 if (u3 > u1) { 280 if ((u2 < u1) || (u2 > u3)) 281 device_printf(acpi_timer_dev, "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n", 282 u1, u2, u3); 283 } 284 u1 = u2; 285 u2 = u3; 286 u3 = TIMER_READ; 287 } 288} 289 290/* 291 * Chipset workaround driver hung off PCI. 292 * 293 * Some ACPI timers are known or believed to suffer from implementation 294 * problems which can lead to erroneous values being read from the timer. 295 * 296 * Since we can't trust unknown chipsets, we default to a timer-read 297 * routine which compensates for the most common problem (as detailed 298 * in the excerpt from the Intel PIIX4 datasheet below). 299 * 300 * When we detect a known-functional chipset, we disable the workaround 301 * to improve speed. 302 * 303 * ] 20. ACPI Timer Errata 304 * ] 305 * ] Problem: The power management timer may return improper result when 306 * ] read. Although the timer value settles properly after incrementing, 307 * ] while incrementing there is a 3nS window every 69.8nS where the 308 * ] timer value is indeterminate (a 4.2% chance that the data will be 309 * ] incorrect when read). As a result, the ACPI free running count up 310 * ] timer specification is violated due to erroneous reads. Implication: 311 * ] System hangs due to the "inaccuracy" of the timer when used by 312 * ] software for time critical events and delays. 313 * ] 314 * ] Workaround: Read the register twice and compare. 315 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed 316 * ] in the PIIX4M. 317 * 318 * The counter is in other words not latched to the PCI bus clock when 319 * read. Notice the workaround isn't: We need to read until we have 320 * three monotonic samples and then use the middle one, otherwise we are 321 * not protected against the fact that the bits can be wrong in two 322 * directions. If we only cared about monosity two reads would be enough. 323 */ 324 325#if 0 326static int acpi_timer_pci_probe(device_t dev); 327 328static device_method_t acpi_timer_pci_methods[] = { 329 DEVMETHOD(device_probe, acpi_timer_pci_probe), 330 {0, 0} 331}; 332 333static driver_t acpi_timer_pci_driver = { 334 "acpi_timer_pci", 335 acpi_timer_pci_methods, 336 0, 337}; 338 339devclass_t acpi_timer_pci_devclass; 340DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver, acpi_timer_pci_devclass, 0, 0); 341 342/* 343 * Look at PCI devices going past; if we detect one we know contains 344 * a functional ACPI timer device, enable the faster timecounter read 345 * routine. 346 */ 347static int 348acpi_timer_pci_probe(device_t dev) 349{ 350 int vendor, device, revid; 351 352 vendor = pci_get_vendor(dev); 353 device = pci_get_device(dev); 354 revid = pci_get_revid(dev); 355 356 if (((vendor == 0x8086) && (device == 0x7113) && (revid >= 0x03)) || /* PIIX4M */ 357 ((vendor == 0x8086) && (device == 0x719b)) || /* i440MX */ 358 0) { 359 360 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount; 361 acpi_timer_timecounter.tc_name = "ACPI-fast"; 362 if (bootverbose) 363 device_printf(acpi_timer_dev, "functional ACPI timer detected, enabling fast timecount interface\n"); 364 } 365 366 return(ENXIO); /* we never match anything */ 367} 368#endif 369