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 "accommon.h"
  44 #include "acpivar.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 /* Hooks for the ACPI CA debugging infrastructure */
  53 #define _COMPONENT      ACPI_TIMER
  54 ACPI_MODULE_NAME("TIMER")
  55
  56 static device_t                 acpi_timer_dev;
  57 static struct resource          *acpi_timer_reg;
  58 static bus_space_handle_t       acpi_timer_bsh;
  59 static bus_space_tag_t          acpi_timer_bst;
  60 static sysclock_t               acpi_counter_mask;
  61 static sysclock_t               acpi_last_counter;
  62
  63 #define ACPI_TIMER_FREQ         (14318182 / 4)
  64
  65 static sysclock_t acpi_timer_get_timecount(void);
  66 static sysclock_t acpi_timer_get_timecount24(void);
  67 static sysclock_t acpi_timer_get_timecount_safe(void);
  68 static void acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock);
  69
  70 static struct cputimer acpi_cputimer = {
  71         SLIST_ENTRY_INITIALIZER,
  72         "ACPI",
  73         CPUTIMER_PRI_ACPI,
  74         CPUTIMER_ACPI,
  75         acpi_timer_get_timecount_safe,
  76         cputimer_default_fromhz,
  77         cputimer_default_fromus,
  78         acpi_timer_construct,
  79         cputimer_default_destruct,
  80         ACPI_TIMER_FREQ,
  81         0, 0, 0
  82 };
  83
  84 static int      acpi_timer_identify(driver_t *driver, device_t parent);
  85 static int      acpi_timer_probe(device_t dev);
  86 static int      acpi_timer_attach(device_t dev);
  87 static int      acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
  88
  89 static u_int    acpi_timer_read(void);
  90 static int      acpi_timer_test(void);
  91
  92 static device_method_t acpi_timer_methods[] = {
  93     DEVMETHOD(device_identify,  acpi_timer_identify),
  94     DEVMETHOD(device_probe,     acpi_timer_probe),
  95     DEVMETHOD(device_attach,    acpi_timer_attach),
  96
  97     {0, 0}
  98 };
  99
 100 static driver_t acpi_timer_driver = {
 101     "acpi_timer",
 102     acpi_timer_methods,
 103     0,
 104 };
 105
 106 static devclass_t acpi_timer_devclass;
 107 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
 108 MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1);
 109
 110 static u_int
 111 acpi_timer_read(void)
 112 {
 113     return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0));
 114 }
 115
 116 /*
 117  * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
 118  * we will be using.
 119  */
 120 static int
 121 acpi_timer_identify(driver_t *driver, device_t parent)
 122 {
 123     device_t dev;
 124     u_long rlen, rstart;
 125     int rid, rtype;
 126
 127     /*
 128      * Just try once, do nothing if the 'acpi' bus is rescanned.
 129      */
 130     if (device_get_state(parent) == DS_ATTACHED)
 131         return (0);
 132
 133     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
 134
 135     if (acpi_disabled("timer") || acpi_timer_dev)
 136         return (ENXIO);
 137
 138     if ((dev = BUS_ADD_CHILD(parent, parent, 0, "acpi_timer", 0)) == NULL) {
 139         device_printf(parent, "could not add acpi_timer0\n");
 140         return (ENXIO);
 141     }
 142     acpi_timer_dev = dev;
 143
 144     rid = 0;
 145     rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
 146         SYS_RES_IOPORT : SYS_RES_MEMORY;
 147     rlen = AcpiGbl_FADT.PmTimerLength;
 148     rstart = AcpiGbl_FADT.XPmTimerBlock.Address;
 149     if (bus_set_resource(dev, rtype, rid, rstart, rlen)) {
 150         device_printf(dev, "couldn't set resource (%s 0x%lx+0x%lx)\n",
 151             (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen);
 152         return (ENXIO);
 153     }
 154     return (0);
 155 }
 156
 157 static int
 158 acpi_timer_probe(device_t dev)
 159 {
 160     char desc[40];
 161     int i, j, rid, rtype;
 162
 163     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
 164
 165     if (dev != acpi_timer_dev)
 166         return (ENXIO);
 167
 168     rid = 0;
 169     rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
 170         SYS_RES_IOPORT : SYS_RES_MEMORY;
 171     acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
 172     if (acpi_timer_reg == NULL) {
 173         device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n",
 174             (rtype == SYS_RES_IOPORT) ? "port" : "mem",
 175             (u_long)AcpiGbl_FADT.XPmTimerBlock.Address);
 176         return (ENXIO);
 177     }
 178     acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
 179     acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
 180     if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) != 0)
 181         acpi_counter_mask = 0xffffffff;
 182     else
 183         acpi_counter_mask = 0x00ffffff;
 184
 185     /*
 186      * If all tests of the counter succeed, use the ACPI-fast method.  If
 187      * at least one failed, default to using the safe routine, which reads
 188      * the timer multiple times to get a consistent value before returning.
 189      */
 190     j = 0;
 191     for (i = 0; i < 10; i++)
 192         j += acpi_timer_test();
 193     if (j == 10) {
 194         if (acpi_counter_mask == 0xffffffff) {
 195             acpi_cputimer.name = "ACPI-fast";
 196             acpi_cputimer.count = acpi_timer_get_timecount;
 197         } else {
 198             acpi_cputimer.name = "ACPI-fast24";
 199             acpi_cputimer.count = acpi_timer_get_timecount24;
 200         }
 201     } else {
 202         if (acpi_counter_mask == 0xffffffff)
 203                 acpi_cputimer.name = "ACPI-safe";
 204         else
 205                 acpi_cputimer.name = "ACPI-safe24";
 206         acpi_cputimer.count = acpi_timer_get_timecount_safe;
 207     }
 208
 209     ksprintf(desc, "%d-bit timer at 3.579545MHz",
 210             (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) ? 32 : 24);
 211     device_set_desc_copy(dev, desc);
 212
 213     cputimer_register(&acpi_cputimer);
 214     cputimer_select(&acpi_cputimer, 0);
 215     /* Release the resource, we'll allocate it again during attach. */
 216     bus_release_resource(dev, rtype, rid, acpi_timer_reg);
 217     return (0);
 218 }
 219
 220 static int
 221 acpi_timer_attach(device_t dev)
 222 {
 223     int rid, rtype;
 224
 225     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
 226
 227     rid = 0;
 228     rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
 229         SYS_RES_IOPORT : SYS_RES_MEMORY;
 230     acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
 231     if (acpi_timer_reg == NULL)
 232         return (ENXIO);
 233     acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
 234     acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
 235     return (0);
 236 }
 237
 238 /*
 239  * Construct the timer.  Adjust the base so the system clock does not
 240  * jump weirdly.
 241  */
 242 static void
 243 acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock)
 244 {
 245     timer->base = 0;
 246     timer->base = oldclock - acpi_timer_get_timecount_safe();
 247 }
 248
 249 /*
 250  * Fetch current time value from reliable hardware.
 251  *
 252  * The cputimer interface requires a 32 bit return value.  If the ACPI timer
 253  * is only 24 bits then we have to keep track of the upper 8 bits on our
 254  * own.
 255  *
 256  * XXX we could probably get away with using a per-cpu field for this and
 257  * just use interrupt disablement instead of clock_lock.
 258  */
 259 static sysclock_t
 260 acpi_timer_get_timecount24(void)
 261 {
 262     sysclock_t counter;
 263
 264     clock_lock();
 265     counter = acpi_timer_read();
 266     if (counter < acpi_last_counter)
 267         acpi_cputimer.base += 0x01000000;
 268     acpi_last_counter = counter;
 269     counter += acpi_cputimer.base;
 270     clock_unlock();
 271     return (counter);
 272 }
 273
 274 static sysclock_t
 275 acpi_timer_get_timecount(void)
 276 {
 277     return (acpi_timer_read() + acpi_cputimer.base);
 278 }
 279
 280 /*
 281  * Fetch current time value from hardware that may not correctly
 282  * latch the counter.  We need to read until we have three monotonic
 283  * samples and then use the middle one, otherwise we are not protected
 284  * against the fact that the bits can be wrong in two directions.  If
 285  * we only cared about monosity, two reads would be enough.
 286  */
 287 static sysclock_t
 288 acpi_timer_get_timecount_safe(void)
 289 {
 290     u_int u1, u2, u3;
 291
 292     if (acpi_counter_mask != 0xffffffff)
 293         clock_lock();
 294
 295     u2 = acpi_timer_read();
 296     u3 = acpi_timer_read();
 297     do {
 298         u1 = u2;
 299         u2 = u3;
 300         u3 = acpi_timer_read();
 301     } while (u1 > u2 || u2 > u3);
 302
 303     if (acpi_counter_mask != 0xffffffff) {
 304         if (u2 < acpi_last_counter)
 305             acpi_cputimer.base += 0x01000000;
 306         acpi_last_counter = u2;
 307         clock_unlock();
 308     }
 309     return (u2 + acpi_cputimer.base);
 310 }
 311
 312 /*
 313  * Timecounter freqency adjustment interface.
 314  */
 315 static int
 316 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
 317 {
 318     int error;
 319     u_int freq;
 320
 321     if (acpi_cputimer.freq == 0)
 322         return (EOPNOTSUPP);
 323     freq = acpi_cputimer.freq;
 324     error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
 325     if (error == 0 && req->newptr != NULL)
 326         cputimer_set_frequency(&acpi_cputimer, freq);
 327
 328     return (error);
 329 }
 330
 331 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
 332             0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
 333
 334 /*
 335  * Some ACPI timers are known or believed to suffer from implementation
 336  * problems which can lead to erroneous values being read.  This function
 337  * tests for consistent results from the timer and returns 1 if it believes
 338  * the timer is consistent, otherwise it returns 0.
 339  *
 340  * It appears the cause is that the counter is not latched to the PCI bus
 341  * clock when read:
 342  *
 343  * ] 20. ACPI Timer Errata
 344  * ]
 345  * ]   Problem: The power management timer may return improper result when
 346  * ]   read. Although the timer value settles properly after incrementing,
 347  * ]   while incrementing there is a 3nS window every 69.8nS where the
 348  * ]   timer value is indeterminate (a 4.2% chance that the data will be
 349  * ]   incorrect when read). As a result, the ACPI free running count up
 350  * ]   timer specification is violated due to erroneous reads.  Implication:
 351  * ]   System hangs due to the "inaccuracy" of the timer when used by
 352  * ]   software for time critical events and delays.
 353  * ]
 354  * ] Workaround: Read the register twice and compare.
 355  * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
 356  * ] in the PIIX4M.
 357  */
 358
 359 static int
 360 acpi_timer_test(void)
 361 {
 362     uint32_t    last, this;
 363     int         min, max, n, delta;
 364     register_t  s;
 365
 366     min = 10000000;
 367     max = 0;
 368
 369     /* Test the timer with interrupts disabled to get accurate results. */
 370 #if defined(__i386__)
 371     s = read_eflags();
 372 #elif defined(__x86_64__)
 373     s = read_rflags();
 374 #else
 375 #error "no read_eflags"
 376 #endif
 377     cpu_disable_intr();
 378     last = acpi_timer_read();
 379     for (n = 0; n < 2000; n++) {
 380         this = acpi_timer_read();
 381         delta = acpi_TimerDelta(this, last);
 382         if (delta > max)
 383             max = delta;
 384         else if (delta < min)
 385             min = delta;
 386         last = this;
 387     }
 388 #if defined(__i386__)
 389     write_eflags(s);
 390 #elif defined(__x86_64__)
 391     write_rflags(s);
 392 #else
 393 #error "no read_eflags"
 394 #endif
 395
 396     if (max - min > 2)
 397         n = 0;
 398     else if (min < 0 || max == 0)
 399         n = 0;
 400     else
 401         n = 1;
 402     if (bootverbose) {
 403         kprintf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
 404                 n ? "GOOD" : "BAD ",
 405                 min, max, max - min);
 406     }
 407
 408     return (n);
 409 }
 410