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