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_pio.h> 37 #include <machine/bus.h> 38 #include <machine/resource.h> 39 #include <sys/rman.h> 40 41 #include "acpi.h" 42 43 #include <acpica/acpivar.h> 44 #include <pci/pcivar.h> 45 46 /* 47 * A timecounter based on the free-running ACPI timer. 48 * 49 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>. 50 */ 51 52 /* 53 * Hooks for the ACPI CA debugging infrastructure 54 */ 55 #define _COMPONENT ACPI_SYSTEM 56 ACPI_MODULE_NAME("TIMER") 57 58 static device_t acpi_timer_dev; 59 struct resource *acpi_timer_reg; 60 #define TIMER_READ bus_space_read_4(rman_get_bustag(acpi_timer_reg), \ 61 rman_get_bushandle(acpi_timer_reg), \ 62 0) 63 64 static u_int acpi_timer_frequency = 14318182/4; 65 66 static void acpi_timer_identify(driver_t *driver, device_t parent); 67 static int acpi_timer_probe(device_t dev); 68 static int acpi_timer_attach(device_t dev); 69 static unsigned acpi_timer_get_timecount(struct timecounter *tc); 70 static unsigned acpi_timer_get_timecount_safe(struct timecounter *tc); 71 static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS); 72 static void acpi_timer_test(void); 73 74 /* 75 * Driver hung off ACPI. 76 */ 77 static device_method_t acpi_timer_methods[] = { 78 DEVMETHOD(device_identify, acpi_timer_identify), 79 DEVMETHOD(device_probe, acpi_timer_probe), 80 DEVMETHOD(device_attach, acpi_timer_attach), 81 82 {0, 0} 83 }; 84 85 static driver_t acpi_timer_driver = { 86 "acpi_timer", 87 acpi_timer_methods, 88 0, 89 }; 90 91 static devclass_t acpi_timer_devclass; 92 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0); 93 94 /* 95 * Timecounter. 96 */ 97 static struct timecounter acpi_timer_timecounter = { 98 acpi_timer_get_timecount_safe, 99 0, 100 0xffffff, 101 0, 102 "ACPI" 103 }; 104 105 SYSCTL_OPAQUE(_debug, OID_AUTO, acpi_timecounter, CTLFLAG_RD, 106 &acpi_timer_timecounter, sizeof(acpi_timer_timecounter), "S,timecounter", ""); 107 static int test_counter(void); 108 109 #define N 2000 110 static int 111 test_counter() 112 { 113 int min, max, n, delta; 114 unsigned last, this; 115 116 min = 10000000; 117 max = 0; 118 last = TIMER_READ; 119 for (n = 0; n < N; n++) { 120 this = TIMER_READ; 121 delta = (this - last) & 0xffffff; 122 if (delta > max) 123 max = delta; 124 else if (delta < min) 125 min = delta; 126 last = this; 127 } 128 if (max - min > 2) 129 n = 0; 130 else if (min < 0) 131 n = 0; 132 else 133 n = 1; 134 printf("ACPI timer looks %s min = %d, max = %d, width = %d\n", 135 n ? "GOOD" : "BAD ", 136 min, max, max - min + 1); 137 return (n); 138 } 139 140 /* 141 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources 142 * we will be using. 143 */ 144 static void 145 acpi_timer_identify(driver_t *driver, device_t parent) 146 { 147 device_t dev; 148 char desc[40]; 149 int rid, i, j; 150 151 ACPI_FUNCTION_TRACE(__func__); 152 153 if (acpi_disabled("timer")) 154 return_VOID; 155 156 if (AcpiGbl_FADT == NULL) 157 return_VOID; 158 159 if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) { 160 device_printf(parent, "could not add acpi_timer0\n"); 161 return_VOID; 162 } 163 acpi_timer_dev = dev; 164 rid = 0; 165 bus_set_resource(dev, SYS_RES_IOPORT, rid, AcpiGbl_FADT->V1_PmTmrBlk, sizeof(u_int32_t)); 166 if ((acpi_timer_reg = bus_alloc_resource(dev, SYS_RES_IOPORT, &rid, 0, ~0, 1, RF_ACTIVE)) == NULL) { 167 device_printf(dev, "couldn't allocate I/O resource (port 0x%x)\n", AcpiGbl_FADT->V1_PmTmrBlk); 168 return_VOID; 169 } 170 if (getenv("debug.acpi.timer_test") != NULL) 171 acpi_timer_test(); 172 173 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 174 j = 0; 175 for(i = 0; i < 10; i++) 176 j += test_counter(); 177 if (j == 10) { 178 acpi_timer_timecounter.tc_name = "ACPI-fast"; 179 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount; 180 } else { 181 acpi_timer_timecounter.tc_name = "ACPI-safe"; 182 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe; 183 } 184 tc_init(&acpi_timer_timecounter); 185 186 sprintf(desc, "%d-bit timer at 3.579545MHz", AcpiGbl_FADT->TmrValExt ? 32 : 24); 187 device_set_desc_copy(dev, desc); 188 189 return_VOID; 190 } 191 192 static int 193 acpi_timer_probe(device_t dev) 194 { 195 if (dev == acpi_timer_dev) 196 return(0); 197 return(ENXIO); 198 } 199 200 static int 201 acpi_timer_attach(device_t dev) 202 { 203 return(0); 204 } 205 206 /* 207 * Fetch current time value from reliable hardware. 208 */ 209 static unsigned 210 acpi_timer_get_timecount(struct timecounter *tc) 211 { 212 return(TIMER_READ); 213 } 214 215 /* 216 * Fetch current time value from hardware that may not correctly 217 * latch the counter. 218 */ 219 static unsigned 220 acpi_timer_get_timecount_safe(struct timecounter *tc) 221 { 222 unsigned u1, u2, u3; 223 224 u2 = TIMER_READ; 225 u3 = TIMER_READ; 226 do { 227 u1 = u2; 228 u2 = u3; 229 u3 = TIMER_READ; 230 } while (u1 > u2 || u2 > u3 || (u3 - u1) > 15); 231 return (u2); 232 } 233 234 /* 235 * Timecounter freqency adjustment interface. 236 */ 237 static int 238 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS) 239 { 240 int error; 241 u_int freq; 242 243 if (acpi_timer_timecounter.tc_frequency == 0) 244 return (EOPNOTSUPP); 245 freq = acpi_timer_frequency; 246 error = sysctl_handle_int(oidp, &freq, sizeof(freq), req); 247 if (error == 0 && req->newptr != NULL) { 248 acpi_timer_frequency = freq; 249 acpi_timer_timecounter.tc_frequency = acpi_timer_frequency; 250 tc_update(&acpi_timer_timecounter); 251 } 252 return (error); 253 } 254 255 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW, 256 0, sizeof(u_int), acpi_timer_sysctl_freq, "I", ""); 257 258 /* 259 * Test harness for verifying ACPI timer behaviour. 260 * Boot with debug.acpi.timer_test set to invoke this. 261 */ 262 static void 263 acpi_timer_test(void) 264 { 265 u_int32_t u1, u2, u3; 266 267 u1 = TIMER_READ; 268 u2 = TIMER_READ; 269 u3 = TIMER_READ; 270 271 device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n"); 272 for (;;) { 273 /* 274 * The failure case is where u3 > u1, but u2 does not fall between the two, 275 * ie. it contains garbage. 276 */ 277 if (u3 > u1) { 278 if ((u2 < u1) || (u2 > u3)) 279 device_printf(acpi_timer_dev, "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n", 280 u1, u2, u3); 281 } 282 u1 = u2; 283 u2 = u3; 284 u3 = TIMER_READ; 285 } 286 } 287 288 /* 289 * Chipset workaround driver hung off PCI. 290 * 291 * Some ACPI timers are known or believed to suffer from implementation 292 * problems which can lead to erroneous values being read from the timer. 293 * 294 * Since we can't trust unknown chipsets, we default to a timer-read 295 * routine which compensates for the most common problem (as detailed 296 * in the excerpt from the Intel PIIX4 datasheet below). 297 * 298 * When we detect a known-functional chipset, we disable the workaround 299 * to improve speed. 300 * 301 * ] 20. ACPI Timer Errata 302 * ] 303 * ] Problem: The power management timer may return improper result when 304 * ] read. Although the timer value settles properly after incrementing, 305 * ] while incrementing there is a 3nS window every 69.8nS where the 306 * ] timer value is indeterminate (a 4.2% chance that the data will be 307 * ] incorrect when read). As a result, the ACPI free running count up 308 * ] timer specification is violated due to erroneous reads. Implication: 309 * ] System hangs due to the "inaccuracy" of the timer when used by 310 * ] software for time critical events and delays. 311 * ] 312 * ] Workaround: Read the register twice and compare. 313 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed 314 * ] in the PIIX4M. 315 * 316 * The counter is in other words not latched to the PCI bus clock when 317 * read. Notice the workaround isn't: We need to read until we have 318 * three monotonic samples and then use the middle one, otherwise we are 319 * not protected against the fact that the bits can be wrong in two 320 * directions. If we only cared about monosity two reads would be enough. 321 */ 322 323 #if 0 324 static int acpi_timer_pci_probe(device_t dev); 325 326 static device_method_t acpi_timer_pci_methods[] = { 327 DEVMETHOD(device_probe, acpi_timer_pci_probe), 328 {0, 0} 329 }; 330 331 static driver_t acpi_timer_pci_driver = { 332 "acpi_timer_pci", 333 acpi_timer_pci_methods, 334 0, 335 }; 336 337 devclass_t acpi_timer_pci_devclass; 338 DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver, acpi_timer_pci_devclass, 0, 0); 339 340 /* 341 * Look at PCI devices going past; if we detect one we know contains 342 * a functional ACPI timer device, enable the faster timecounter read 343 * routine. 344 */ 345 static int 346 acpi_timer_pci_probe(device_t dev) 347 { 348 int vendor, device, revid; 349 350 vendor = pci_get_vendor(dev); 351 device = pci_get_device(dev); 352 revid = pci_get_revid(dev); 353 354 if (((vendor == 0x8086) && (device == 0x7113) && (revid >= 0x03)) || /* PIIX4M */ 355 ((vendor == 0x8086) && (device == 0x719b)) || /* i440MX */ 356 0) { 357 358 acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount; 359 acpi_timer_timecounter.tc_name = "ACPI-fast"; 360 if (bootverbose) 361 device_printf(acpi_timer_dev, "functional ACPI timer detected, enabling fast timecount interface\n"); 362 } 363 364 return(ENXIO); /* we never match anything */ 365 } 366 #endif 367