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