sys/dev/acpica5/acpi_timer.c

   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: src/sys/dev/acpica/acpi_timer.c,v 1.35 2004/07/22 05:42:14 njl Exp $
  28  * $DragonFly: src/sys/dev/acpica5/acpi_timer.c,v 1.13 2007/10/09 09:46:56 y0netan1 Exp $
  29  */
  30 #include "opt_acpi.h"
  31 #include <sys/param.h>
  32 #include <sys/bus.h>
  33 #include <sys/kernel.h>
  34 #include <sys/module.h>
  35 #include <sys/sysctl.h>
  36 #include <sys/systimer.h>
  37 #include <sys/rman.h>
  38
  39 #include <machine/lock.h>
  40 #include <bus/pci/pcivar.h>
  41
  42 #include "acpi.h"
  43 #include "acpivar.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 static sysclock_t               acpi_counter_mask;
  60 static sysclock_t               acpi_last_counter;
  61
  62 #define ACPI_TIMER_FREQ         (14318182 / 4)
  63
  64 static sysclock_t acpi_timer_get_timecount(void);
  65 static sysclock_t acpi_timer_get_timecount24(void);
  66 static sysclock_t acpi_timer_get_timecount_safe(void);
  67 static void acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock);
  68
  69 static struct cputimer acpi_cputimer = {
  70         SLIST_ENTRY_INITIALIZER,
  71         "ACPI",
  72         CPUTIMER_PRI_ACPI,
  73         CPUTIMER_ACPI,
  74         acpi_timer_get_timecount_safe,
  75         cputimer_default_fromhz,
  76         cputimer_default_fromus,
  77         acpi_timer_construct,
  78         cputimer_default_destruct,
  79         ACPI_TIMER_FREQ,
  80         0, 0, 0
  81 };
  82
  83 static int      acpi_timer_identify(driver_t *driver, device_t parent);
  84 static int      acpi_timer_probe(device_t dev);
  85 static int      acpi_timer_attach(device_t dev);
  86 static int      acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
  87
  88 static u_int    acpi_timer_read(void);
  89 static int      acpi_timer_test(void);
  90
  91 static device_method_t acpi_timer_methods[] = {
  92     DEVMETHOD(device_identify,  acpi_timer_identify),
  93     DEVMETHOD(device_probe,     acpi_timer_probe),
  94     DEVMETHOD(device_attach,    acpi_timer_attach),
  95
  96     {0, 0}
  97 };
  98
  99 static driver_t acpi_timer_driver = {
 100     "acpi_timer",
 101     acpi_timer_methods,
 102     0,
 103 };
 104
 105 static devclass_t acpi_timer_devclass;
 106 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
 107 MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1);
 108
 109 static u_int
 110 acpi_timer_read(void)
 111 {
 112     return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0));
 113 }
 114
 115 /*
 116  * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
 117  * we will be using.
 118  */
 119 static int
 120 acpi_timer_identify(driver_t *driver, device_t parent)
 121 {
 122     device_t dev;
 123     u_long rlen, rstart;
 124     int rid, rtype;
 125
 126     /*
 127      * Just try once, do nothing if the 'acpi' bus is rescanned.
 128      */
 129     if (device_get_state(parent) == DS_ATTACHED)
 130         return (0);
 131
 132     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
 133
 134     if (acpi_disabled("timer") || acpi_timer_dev)
 135         return (ENXIO);
 136
 137     if ((dev = BUS_ADD_CHILD(parent, parent, 0, "acpi_timer", 0)) == NULL) {
 138         device_printf(parent, "could not add acpi_timer0\n");
 139         return (ENXIO);
 140     }
 141     acpi_timer_dev = dev;
 142
 143     rid = 0;
 144     rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
 145         SYS_RES_IOPORT : SYS_RES_MEMORY;
 146     rlen = AcpiGbl_FADT.PmTimerLength;
 147     rstart = AcpiGbl_FADT.XPmTimerBlock.Address;
 148     if (bus_set_resource(dev, rtype, rid, rstart, rlen)) {
 149         device_printf(dev, "couldn't set resource (%s 0x%lx+0x%lx)\n",
 150             (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen);
 151         return (ENXIO);
 152     }
 153     return (0);
 154 }
 155
 156 static int
 157 acpi_timer_probe(device_t dev)
 158 {
 159     char desc[40];
 160     int i, j, rid, rtype;
 161
 162     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
 163
 164     if (dev != acpi_timer_dev)
 165         return (ENXIO);
 166
 167     rid = 0;
 168     rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
 169         SYS_RES_IOPORT : SYS_RES_MEMORY;
 170     acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
 171     if (acpi_timer_reg == NULL) {
 172         device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n",
 173             (rtype == SYS_RES_IOPORT) ? "port" : "mem",
 174             (u_long)AcpiGbl_FADT.XPmTimerBlock.Address);
 175         return (ENXIO);
 176     }
 177     acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
 178     acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
 179     if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) != 0)
 180         acpi_counter_mask = 0xffffffff;
 181     else
 182         acpi_counter_mask = 0x00ffffff;
 183
 184     /*
 185      * If all tests of the counter succeed, use the ACPI-fast method.  If
 186      * at least one failed, default to using the safe routine, which reads
 187      * the timer multiple times to get a consistent value before returning.
 188      */
 189     j = 0;
 190     for (i = 0; i < 10; i++)
 191         j += acpi_timer_test();
 192     if (j == 10) {
 193         if (acpi_counter_mask == 0xffffffff) {
 194             acpi_cputimer.name = "ACPI-fast";
 195             acpi_cputimer.count = acpi_timer_get_timecount;
 196         } else {
 197             acpi_cputimer.name = "ACPI-fast24";
 198             acpi_cputimer.count = acpi_timer_get_timecount24;
 199         }
 200     } else {
 201         if (acpi_counter_mask == 0xffffffff)
 202                 acpi_cputimer.name = "ACPI-safe";
 203         else
 204                 acpi_cputimer.name = "ACPI-safe24";
 205         acpi_cputimer.count = acpi_timer_get_timecount_safe;
 206     }
 207
 208     ksprintf(desc, "%d-bit timer at 3.579545MHz",
 209             (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) ? 32 : 24);
 210     device_set_desc_copy(dev, desc);
 211
 212     cputimer_register(&acpi_cputimer);
 213     cputimer_select(&acpi_cputimer, 0);
 214     /* Release the resource, we'll allocate it again during attach. */
 215     bus_release_resource(dev, rtype, rid, acpi_timer_reg);
 216     return (0);
 217 }
 218
 219 static int
 220 acpi_timer_attach(device_t dev)
 221 {
 222     int rid, rtype;
 223
 224     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
 225
 226     rid = 0;
 227     rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
 228         SYS_RES_IOPORT : SYS_RES_MEMORY;
 229     acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
 230     if (acpi_timer_reg == NULL)
 231         return (ENXIO);
 232     acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
 233     acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
 234     return (0);
 235 }
 236
 237 /*
 238  * Construct the timer.  Adjust the base so the system clock does not
 239  * jump weirdly.
 240  */
 241 static void
 242 acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock)
 243 {
 244     timer->base = 0;
 245     timer->base = oldclock - acpi_timer_get_timecount_safe();
 246 }
 247
 248 /*
 249  * Fetch current time value from reliable hardware.
 250  *
 251  * The cputimer interface requires a 32 bit return value.  If the ACPI timer
 252  * is only 24 bits then we have to keep track of the upper 8 bits on our
 253  * own.
 254  *
 255  * XXX we could probably get away with using a per-cpu field for this and
 256  * just use interrupt disablement instead of clock_lock.
 257  */
 258 static sysclock_t
 259 acpi_timer_get_timecount24(void)
 260 {
 261     sysclock_t counter;
 262
 263     clock_lock();
 264     counter = acpi_timer_read();
 265     if (counter < acpi_last_counter)
 266         acpi_cputimer.base += 0x01000000;
 267     acpi_last_counter = counter;
 268     counter += acpi_cputimer.base;
 269     clock_unlock();
 270     return (counter);
 271 }
 272
 273 static sysclock_t
 274 acpi_timer_get_timecount(void)
 275 {
 276     return (acpi_timer_read() + acpi_cputimer.base);
 277 }
 278
 279 /*
 280  * Fetch current time value from hardware that may not correctly
 281  * latch the counter.  We need to read until we have three monotonic
 282  * samples and then use the middle one, otherwise we are not protected
 283  * against the fact that the bits can be wrong in two directions.  If
 284  * we only cared about monosity, two reads would be enough.
 285  */
 286 static sysclock_t
 287 acpi_timer_get_timecount_safe(void)
 288 {
 289     u_int u1, u2, u3;
 290
 291     if (acpi_counter_mask != 0xffffffff)
 292         clock_lock();
 293
 294     u2 = acpi_timer_read();
 295     u3 = acpi_timer_read();
 296     do {
 297         u1 = u2;
 298         u2 = u3;
 299         u3 = acpi_timer_read();
 300     } while (u1 > u2 || u2 > u3);
 301
 302     if (acpi_counter_mask != 0xffffffff) {
 303         if (u2 < acpi_last_counter)
 304             acpi_cputimer.base += 0x01000000;
 305         acpi_last_counter = u2;
 306         clock_unlock();
 307     }
 308     return (u2 + acpi_cputimer.base);
 309 }
 310
 311 /*
 312  * Timecounter freqency adjustment interface.
 313  */
 314 static int
 315 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
 316 {
 317     int error;
 318     u_int freq;
 319
 320     if (acpi_cputimer.freq == 0)
 321         return (EOPNOTSUPP);
 322     freq = acpi_cputimer.freq;
 323     error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
 324     if (error == 0 && req->newptr != NULL)
 325         cputimer_set_frequency(&acpi_cputimer, freq);
 326
 327     return (error);
 328 }
 329
 330 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
 331             0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
 332
 333 /*
 334  * Some ACPI timers are known or believed to suffer from implementation
 335  * problems which can lead to erroneous values being read.  This function
 336  * tests for consistent results from the timer and returns 1 if it believes
 337  * the timer is consistent, otherwise it returns 0.
 338  *
 339  * It appears the cause is that the counter is not latched to the PCI bus
 340  * clock when read:
 341  *
 342  * ] 20. ACPI Timer Errata
 343  * ]
 344  * ]   Problem: The power management timer may return improper result when
 345  * ]   read. Although the timer value settles properly after incrementing,
 346  * ]   while incrementing there is a 3nS window every 69.8nS where the
 347  * ]   timer value is indeterminate (a 4.2% chance that the data will be
 348  * ]   incorrect when read). As a result, the ACPI free running count up
 349  * ]   timer specification is violated due to erroneous reads.  Implication:
 350  * ]   System hangs due to the "inaccuracy" of the timer when used by
 351  * ]   software for time critical events and delays.
 352  * ]
 353  * ] Workaround: Read the register twice and compare.
 354  * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
 355  * ] in the PIIX4M.
 356  */
 357
 358 static int
 359 acpi_timer_test(void)
 360 {
 361     uint32_t    last, this;
 362     int         min, max, n, delta;
 363     register_t  s;
 364
 365     min = 10000000;
 366     max = 0;
 367
 368     /* Test the timer with interrupts disabled to get accurate results. */
 369 #if defined(__i386__)
 370     s = read_eflags();
 371 #elif defined(__amd64__)
 372     s = read_rflags();
 373 #else
 374 #error "no read_eflags"
 375 #endif
 376     cpu_disable_intr();
 377     last = acpi_timer_read();
 378     for (n = 0; n < 2000; n++) {
 379         this = acpi_timer_read();
 380         delta = acpi_TimerDelta(this, last);
 381         if (delta > max)
 382             max = delta;
 383         else if (delta < min)
 384             min = delta;
 385         last = this;
 386     }
 387 #if defined(__i386__)
 388     write_eflags(s);
 389 #elif defined(__amd64__)
 390     write_rflags(s);
 391 #else
 392 #error "no read_eflags"
 393 #endif
 394
 395     if (max - min > 2)
 396         n = 0;
 397     else if (min < 0 || max == 0)
 398         n = 0;
 399     else
 400         n = 1;
 401     if (bootverbose) {
 402         kprintf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
 403                 n ? "GOOD" : "BAD ",
 404                 min, max, max - min);
 405     }
 406
 407     return (n);
 408 }
 409