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 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include "opt_acpi.h" 32 #include <sys/param.h> 33 #include <sys/bus.h> 34 #include <sys/kernel.h> 35 #include <sys/module.h> 36 #include <sys/sysctl.h> 37 #include <sys/timetc.h> 38 39 #include <machine/bus.h> 40 #include <machine/resource.h> 41 #include <sys/rman.h> 42 43 #include <contrib/dev/acpica/acpi.h> 44 #include <dev/acpica/acpivar.h> 45 #include <dev/pci/pcivar.h> 46 47 /* 48 * A timecounter based on the free-running ACPI timer. 49 * 50 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>. 51 */ 52 53 /* Hooks for the ACPI CA debugging infrastructure */ 54 #define _COMPONENT ACPI_TIMER 55 ACPI_MODULE_NAME("TIMER") 56 57 static device_t acpi_timer_dev; 58 static struct resource *acpi_timer_reg; 59 static bus_space_handle_t acpi_timer_bsh; 60 static bus_space_tag_t acpi_timer_bst; 61 62 static u_int acpi_timer_frequency = 14318182 / 4; 63 64 static void acpi_timer_identify(driver_t *driver, device_t parent); 65 static int acpi_timer_probe(device_t dev); 66 static int acpi_timer_attach(device_t dev); 67 static u_int acpi_timer_get_timecount(struct timecounter *tc); 68 static u_int acpi_timer_get_timecount_safe(struct timecounter *tc); 69 static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS); 70 static void acpi_timer_boot_test(void); 71 72 static u_int acpi_timer_read(void); 73 static int acpi_timer_test(void); 74 75 static device_method_t acpi_timer_methods[] = { 76 DEVMETHOD(device_identify, acpi_timer_identify), 77 DEVMETHOD(device_probe, acpi_timer_probe), 78 DEVMETHOD(device_attach, acpi_timer_attach), 79 80 {0, 0} 81 }; 82 83 static driver_t acpi_timer_driver = { 84 "acpi_timer", 85 acpi_timer_methods, 86 0, 87 }; 88 89 static devclass_t acpi_timer_devclass; 90 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0); 91 MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1); 92 93 static struct timecounter acpi_timer_timecounter = { 94 acpi_timer_get_timecount_safe, /* get_timecount function */ 95 0, /* no poll_pps */ 96 0, /* no default counter_mask */ 97 0, /* no default frequency */ 98 "ACPI", /* name */ 99 -1 /* quality (chosen later) */ 100 }; 101 102 static u_int 103 acpi_timer_read() 104 { 105 return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0)); 106 } 107 108 /* 109 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources 110 * we will be using. 111 */ 112 static void 113 acpi_timer_identify(driver_t *driver, device_t parent) 114 { 115 device_t dev; 116 u_long rlen, rstart; 117 int rid, rtype; 118 119 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 120 121 if (acpi_disabled("timer") || (acpi_quirks & ACPI_Q_TIMER) || 122 acpi_timer_dev) 123 return_VOID; 124 125 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) { 126 device_printf(parent, "could not add acpi_timer0\n"); 127 return_VOID; 128 } 129 acpi_timer_dev = dev; 130 131 rid = 0; 132 rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ? 133 SYS_RES_IOPORT : SYS_RES_MEMORY; 134 rlen = AcpiGbl_FADT.PmTimerLength; 135 rstart = AcpiGbl_FADT.XPmTimerBlock.Address; 136 if (bus_set_resource(dev, rtype, rid, rstart, rlen)) 137 device_printf(dev, "couldn't set resource (%s 0x%lx+0x%lx)\n", 138 (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen); 139 return_VOID; 140 } 141 142 static int 143 acpi_timer_probe(device_t dev) 144 { 145 char desc[40]; 146 int i, j, rid, rtype; 147 148 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 149 150 if (dev != acpi_timer_dev) 151 return (ENXIO); 152 153 rid = 0; 154 rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ? 155 SYS_RES_IOPORT : SYS_RES_MEMORY; 156 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE); 157 if (acpi_timer_reg == NULL) { 158 device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n", 159 (rtype == SYS_RES_IOPORT) ? "port" : "mem", 160 (u_long)AcpiGbl_FADT.XPmTimerBlock.Address); 161 return (ENXIO); 162 } 163 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg); 164 acpi_timer_bst = rman_get_bustag(acpi_timer_reg); 165 if (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) 166 acpi_timer_timecounter.tc_counter_mask = 0xffffffff; 167 else 168 acpi_timer_timecounter.tc_counter_mask = 0x00ffffff; 169 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 170 if (testenv("debug.acpi.timer_test")) 171 acpi_timer_boot_test(); 172 173 /* 174 * If all tests of the counter succeed, use the ACPI-fast method. If 175 * at least one failed, default to using the safe routine, which reads 176 * the timer multiple times to get a consistent value before returning. 177 */ 178 j = 0; 179 if (bootverbose) 180 printf("ACPI timer:"); 181 for (i = 0; i < 10; i++) 182 j += acpi_timer_test(); 183 if (bootverbose) 184 printf(" -> %d\n", j); 185 if (j == 10) { 186 acpi_timer_timecounter.tc_name = "ACPI-fast"; 187 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount; 188 acpi_timer_timecounter.tc_quality = 1000; 189 } else { 190 acpi_timer_timecounter.tc_name = "ACPI-safe"; 191 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe; 192 acpi_timer_timecounter.tc_quality = 850; 193 } 194 tc_init(&acpi_timer_timecounter); 195 196 sprintf(desc, "%d-bit timer at 3.579545MHz", 197 (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) ? 32 : 24); 198 device_set_desc_copy(dev, desc); 199 200 /* Release the resource, we'll allocate it again during attach. */ 201 bus_release_resource(dev, rtype, rid, acpi_timer_reg); 202 return (0); 203 } 204 205 static int 206 acpi_timer_attach(device_t dev) 207 { 208 int rid, rtype; 209 210 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 211 212 rid = 0; 213 rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ? 214 SYS_RES_IOPORT : SYS_RES_MEMORY; 215 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE); 216 if (acpi_timer_reg == NULL) 217 return (ENXIO); 218 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg); 219 acpi_timer_bst = rman_get_bustag(acpi_timer_reg); 220 return (0); 221 } 222 223 /* 224 * Fetch current time value from reliable hardware. 225 */ 226 static u_int 227 acpi_timer_get_timecount(struct timecounter *tc) 228 { 229 return (acpi_timer_read()); 230 } 231 232 /* 233 * Fetch current time value from hardware that may not correctly 234 * latch the counter. We need to read until we have three monotonic 235 * samples and then use the middle one, otherwise we are not protected 236 * against the fact that the bits can be wrong in two directions. If 237 * we only cared about monosity, two reads would be enough. 238 */ 239 static u_int 240 acpi_timer_get_timecount_safe(struct timecounter *tc) 241 { 242 u_int u1, u2, u3; 243 244 u2 = acpi_timer_read(); 245 u3 = acpi_timer_read(); 246 do { 247 u1 = u2; 248 u2 = u3; 249 u3 = acpi_timer_read(); 250 } while (u1 > u2 || u2 > u3); 251 252 return (u2); 253 } 254 255 /* 256 * Timecounter freqency adjustment interface. 257 */ 258 static int 259 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS) 260 { 261 int error; 262 u_int freq; 263 264 if (acpi_timer_timecounter.tc_frequency == 0) 265 return (EOPNOTSUPP); 266 freq = acpi_timer_frequency; 267 error = sysctl_handle_int(oidp, &freq, 0, req); 268 if (error == 0 && req->newptr != NULL) { 269 acpi_timer_frequency = freq; 270 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 271 } 272 273 return (error); 274 } 275 276 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW, 277 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", ""); 278 279 /* 280 * Some ACPI timers are known or believed to suffer from implementation 281 * problems which can lead to erroneous values being read. This function 282 * tests for consistent results from the timer and returns 1 if it believes 283 * the timer is consistent, otherwise it returns 0. 284 * 285 * It appears the cause is that the counter is not latched to the PCI bus 286 * clock when read: 287 * 288 * ] 20. ACPI Timer Errata 289 * ] 290 * ] Problem: The power management timer may return improper result when 291 * ] read. Although the timer value settles properly after incrementing, 292 * ] while incrementing there is a 3nS window every 69.8nS where the 293 * ] timer value is indeterminate (a 4.2% chance that the data will be 294 * ] incorrect when read). As a result, the ACPI free running count up 295 * ] timer specification is violated due to erroneous reads. Implication: 296 * ] System hangs due to the "inaccuracy" of the timer when used by 297 * ] software for time critical events and delays. 298 * ] 299 * ] Workaround: Read the register twice and compare. 300 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed 301 * ] in the PIIX4M. 302 */ 303 #define N 2000 304 static int 305 acpi_timer_test() 306 { 307 uint32_t last, this; 308 int min, max, n, delta; 309 register_t s; 310 311 min = 10000000; 312 max = 0; 313 314 /* Test the timer with interrupts disabled to get accurate results. */ 315 s = intr_disable(); 316 last = acpi_timer_read(); 317 for (n = 0; n < N; n++) { 318 this = acpi_timer_read(); 319 delta = acpi_TimerDelta(this, last); 320 if (delta > max) 321 max = delta; 322 else if (delta < min) 323 min = delta; 324 last = this; 325 } 326 intr_restore(s); 327 328 if (max - min > 2) 329 n = 0; 330 else if (min < 0 || max == 0) 331 n = 0; 332 else 333 n = 1; 334 if (bootverbose) 335 printf(" %d/%d", n, max-min); 336 337 return (n); 338 } 339 #undef N 340 341 /* 342 * Test harness for verifying ACPI timer behaviour. 343 * Boot with debug.acpi.timer_test set to invoke this. 344 */ 345 static void 346 acpi_timer_boot_test(void) 347 { 348 uint32_t u1, u2, u3; 349 350 u1 = acpi_timer_read(); 351 u2 = acpi_timer_read(); 352 u3 = acpi_timer_read(); 353 354 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n"); 355 for (;;) { 356 /* 357 * The failure case is where u3 > u1, but u2 does not fall between 358 * the two, ie. it contains garbage. 359 */ 360 if (u3 > u1) { 361 if (u2 < u1 || u2 > u3) 362 device_printf(acpi_timer_dev, 363 "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n", 364 u1, u2, u3); 365 } 366 u1 = u2; 367 u2 = u3; 368 u3 = acpi_timer_read(); 369 } 370 } 371