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 * $FreeBSD$ 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 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 60 static u_int acpi_timer_frequency = 14318182 / 4; 61 62 static void acpi_timer_identify(driver_t *driver, device_t parent); 63 static int acpi_timer_probe(device_t dev); 64 static int acpi_timer_attach(device_t dev); 65 static u_int acpi_timer_get_timecount(struct timecounter *tc); 66 static u_int acpi_timer_get_timecount_safe(struct timecounter *tc); 67 static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS); 68 static void acpi_timer_boot_test(void); 69 70 static u_int acpi_timer_read(void); 71 static int acpi_timer_test(void); 72 73 static 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 81 static driver_t acpi_timer_driver = { 82 "acpi_timer", 83 acpi_timer_methods, 84 0, 85 }; 86 87 static devclass_t acpi_timer_devclass; 88 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0); 89 MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1); 90 91 static 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 }; 99 100 static u_int 101 acpi_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 */ 110 static void 111 acpi_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") || (acpi_quirks & ACPI_Q_TIMER) || 120 AcpiGbl_FADT == NULL || acpi_timer_dev) 121 return_VOID; 122 123 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) { 124 device_printf(parent, "could not add acpi_timer0\n"); 125 return_VOID; 126 } 127 acpi_timer_dev = dev; 128 129 rid = 0; 130 rtype = AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId ? 131 SYS_RES_IOPORT : SYS_RES_MEMORY; 132 rlen = AcpiGbl_FADT->PmTmLen; 133 rstart = AcpiGbl_FADT->XPmTmrBlk.Address; 134 if (bus_set_resource(dev, rtype, rid, rstart, rlen)) 135 device_printf(dev, "couldn't set resource (%s 0x%lx+0x%lx)\n", 136 (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen); 137 return_VOID; 138 } 139 140 static int 141 acpi_timer_probe(device_t dev) 142 { 143 char desc[40]; 144 int i, j, rid, rtype; 145 146 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 147 148 if (dev != acpi_timer_dev) 149 return (ENXIO); 150 151 rid = 0; 152 rtype = AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId ? 153 SYS_RES_IOPORT : SYS_RES_MEMORY; 154 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE); 155 if (acpi_timer_reg == NULL) { 156 device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n", 157 (rtype == SYS_RES_IOPORT) ? "port" : "mem", 158 (u_long)AcpiGbl_FADT->XPmTmrBlk.Address); 159 return (ENXIO); 160 } 161 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg); 162 acpi_timer_bst = rman_get_bustag(acpi_timer_reg); 163 if (AcpiGbl_FADT->TmrValExt != 0) 164 acpi_timer_timecounter.tc_counter_mask = 0xffffffff; 165 else 166 acpi_timer_timecounter.tc_counter_mask = 0x00ffffff; 167 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 168 if (testenv("debug.acpi.timer_test")) 169 acpi_timer_boot_test(); 170 171 /* 172 * If all tests of the counter succeed, use the ACPI-fast method. If 173 * at least one failed, default to using the safe routine, which reads 174 * the timer multiple times to get a consistent value before returning. 175 */ 176 j = 0; 177 for (i = 0; i < 10; i++) 178 j += acpi_timer_test(); 179 if (j == 10) { 180 acpi_timer_timecounter.tc_name = "ACPI-fast"; 181 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount; 182 } else { 183 acpi_timer_timecounter.tc_name = "ACPI-safe"; 184 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe; 185 } 186 tc_init(&acpi_timer_timecounter); 187 188 sprintf(desc, "%d-bit timer at 3.579545MHz", 189 AcpiGbl_FADT->TmrValExt ? 32 : 24); 190 device_set_desc_copy(dev, desc); 191 192 /* Release the resource, we'll allocate it again during attach. */ 193 bus_release_resource(dev, rtype, rid, acpi_timer_reg); 194 return (0); 195 } 196 197 static int 198 acpi_timer_attach(device_t dev) 199 { 200 int rid, rtype; 201 202 ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__); 203 204 rid = 0; 205 rtype = AcpiGbl_FADT->XPmTmrBlk.AddressSpaceId ? 206 SYS_RES_IOPORT : SYS_RES_MEMORY; 207 acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE); 208 if (acpi_timer_reg == NULL) 209 return (ENXIO); 210 acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg); 211 acpi_timer_bst = rman_get_bustag(acpi_timer_reg); 212 return (0); 213 } 214 215 /* 216 * Fetch current time value from reliable hardware. 217 */ 218 static u_int 219 acpi_timer_get_timecount(struct timecounter *tc) 220 { 221 return (acpi_timer_read()); 222 } 223 224 /* 225 * Fetch current time value from hardware that may not correctly 226 * latch the counter. We need to read until we have three monotonic 227 * samples and then use the middle one, otherwise we are not protected 228 * against the fact that the bits can be wrong in two directions. If 229 * we only cared about monosity, two reads would be enough. 230 */ 231 static u_int 232 acpi_timer_get_timecount_safe(struct timecounter *tc) 233 { 234 u_int u1, u2, u3; 235 236 u2 = acpi_timer_read(); 237 u3 = acpi_timer_read(); 238 do { 239 u1 = u2; 240 u2 = u3; 241 u3 = acpi_timer_read(); 242 } while (u1 > u2 || u2 > u3); 243 244 return (u2); 245 } 246 247 /* 248 * Timecounter freqency adjustment interface. 249 */ 250 static int 251 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS) 252 { 253 int error; 254 u_int freq; 255 256 if (acpi_timer_timecounter.tc_frequency == 0) 257 return (EOPNOTSUPP); 258 freq = acpi_timer_frequency; 259 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req); 260 if (error == 0 && req->newptr != NULL) { 261 acpi_timer_frequency = freq; 262 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 263 } 264 265 return (error); 266 } 267 268 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW, 269 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", ""); 270 271 /* 272 * Some ACPI timers are known or believed to suffer from implementation 273 * problems which can lead to erroneous values being read. This function 274 * tests for consistent results from the timer and returns 1 if it believes 275 * the timer is consistent, otherwise it returns 0. 276 * 277 * It appears the cause is that the counter is not latched to the PCI bus 278 * clock when read: 279 * 280 * ] 20. ACPI Timer Errata 281 * ] 282 * ] Problem: The power management timer may return improper result when 283 * ] read. Although the timer value settles properly after incrementing, 284 * ] while incrementing there is a 3nS window every 69.8nS where the 285 * ] timer value is indeterminate (a 4.2% chance that the data will be 286 * ] incorrect when read). As a result, the ACPI free running count up 287 * ] timer specification is violated due to erroneous reads. Implication: 288 * ] System hangs due to the "inaccuracy" of the timer when used by 289 * ] software for time critical events and delays. 290 * ] 291 * ] Workaround: Read the register twice and compare. 292 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed 293 * ] in the PIIX4M. 294 */ 295 #define N 2000 296 static int 297 acpi_timer_test() 298 { 299 uint32_t last, this; 300 int min, max, n, delta; 301 register_t s; 302 303 min = 10000000; 304 max = 0; 305 306 /* Test the timer with interrupts disabled to get accurate results. */ 307 s = intr_disable(); 308 last = acpi_timer_read(); 309 for (n = 0; n < N; n++) { 310 this = acpi_timer_read(); 311 delta = acpi_TimerDelta(this, last); 312 if (delta > max) 313 max = delta; 314 else if (delta < min) 315 min = delta; 316 last = this; 317 } 318 intr_restore(s); 319 320 if (max - min > 2) 321 n = 0; 322 else if (min < 0 || max == 0) 323 n = 0; 324 else 325 n = 1; 326 if (bootverbose) { 327 printf("ACPI timer looks %s min = %d, max = %d, width = %d\n", 328 n ? "GOOD" : "BAD ", 329 min, max, max - min); 330 } 331 332 return (n); 333 } 334 #undef N 335 336 /* 337 * Test harness for verifying ACPI timer behaviour. 338 * Boot with debug.acpi.timer_test set to invoke this. 339 */ 340 static void 341 acpi_timer_boot_test(void) 342 { 343 uint32_t u1, u2, u3; 344 345 u1 = acpi_timer_read(); 346 u2 = acpi_timer_read(); 347 u3 = acpi_timer_read(); 348 349 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n"); 350 for (;;) { 351 /* 352 * The failure case is where u3 > u1, but u2 does not fall between 353 * the two, ie. it contains garbage. 354 */ 355 if (u3 > u1) { 356 if (u2 < u1 || u2 > u3) 357 device_printf(acpi_timer_dev, 358 "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n", 359 u1, u2, u3); 360 } 361 u1 = u2; 362 u2 = u3; 363 u3 = acpi_timer_read(); 364 } 365 } 366