The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/dev/acpica/acpi_timer.c

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    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 
   28 #include <sys/cdefs.h>
   29 __FBSDID("$FreeBSD$");
   30 
   31 #include "opt_acpi.h"
   32 #include <sys/param.h>
   33 #include <sys/bus.h>
   34 #include <sys/eventhandler.h>
   35 #include <sys/kernel.h>
   36 #include <sys/module.h>
   37 #include <sys/sysctl.h>
   38 #include <sys/timetc.h>
   39 
   40 #include <machine/bus.h>
   41 #include <machine/resource.h>
   42 #include <sys/rman.h>
   43 
   44 #include <contrib/dev/acpica/include/acpi.h>
   45 #include <contrib/dev/acpica/include/accommon.h>
   46 
   47 #include <dev/acpica/acpivar.h>
   48 #include <dev/pci/pcivar.h>
   49 
   50 /*
   51  * A timecounter based on the free-running ACPI timer.
   52  *
   53  * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
   54  */
   55 
   56 /* Hooks for the ACPI CA debugging infrastructure */
   57 #define _COMPONENT      ACPI_TIMER
   58 ACPI_MODULE_NAME("TIMER")
   59 
   60 static device_t                 acpi_timer_dev;
   61 static struct resource          *acpi_timer_reg;
   62 static bus_space_handle_t       acpi_timer_bsh;
   63 static bus_space_tag_t          acpi_timer_bst;
   64 static eventhandler_tag         acpi_timer_eh;
   65 
   66 static u_int    acpi_timer_frequency = 14318182 / 4;
   67 
   68 /* Knob to disable acpi_timer device */
   69 bool acpi_timer_disabled = false;
   70 
   71 static void     acpi_timer_identify(driver_t *driver, device_t parent);
   72 static int      acpi_timer_probe(device_t dev);
   73 static int      acpi_timer_attach(device_t dev);
   74 static void     acpi_timer_resume_handler(struct timecounter *);
   75 static void     acpi_timer_suspend_handler(struct timecounter *);
   76 static u_int    acpi_timer_get_timecount(struct timecounter *tc);
   77 static u_int    acpi_timer_get_timecount_safe(struct timecounter *tc);
   78 static int      acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
   79 static void     acpi_timer_boot_test(void);
   80 
   81 static int      acpi_timer_test(void);
   82 
   83 static device_method_t acpi_timer_methods[] = {
   84     DEVMETHOD(device_identify,  acpi_timer_identify),
   85     DEVMETHOD(device_probe,     acpi_timer_probe),
   86     DEVMETHOD(device_attach,    acpi_timer_attach),
   87 
   88     DEVMETHOD_END
   89 };
   90 
   91 static driver_t acpi_timer_driver = {
   92     "acpi_timer",
   93     acpi_timer_methods,
   94     0,
   95 };
   96 
   97 static devclass_t acpi_timer_devclass;
   98 DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
   99 MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1);
  100 
  101 static struct timecounter acpi_timer_timecounter = {
  102         acpi_timer_get_timecount_safe,  /* get_timecount function */
  103         0,                              /* no poll_pps */
  104         0,                              /* no default counter_mask */
  105         0,                              /* no default frequency */
  106         "ACPI",                         /* name */
  107         -1                              /* quality (chosen later) */
  108 };
  109 
  110 static __inline uint32_t
  111 acpi_timer_read(void)
  112 {
  113 
  114     return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0));
  115 }
  116 
  117 /*
  118  * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
  119  * we will be using.
  120  */
  121 static void
  122 acpi_timer_identify(driver_t *driver, device_t parent)
  123 {
  124     device_t dev;
  125     rman_res_t rlen, rstart;
  126     int rid, rtype;
  127 
  128     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
  129 
  130     if (acpi_disabled("timer") || (acpi_quirks & ACPI_Q_TIMER) ||
  131         acpi_timer_dev || acpi_timer_disabled ||
  132         AcpiGbl_FADT.PmTimerLength == 0)
  133         return_VOID;
  134 
  135     if ((dev = BUS_ADD_CHILD(parent, 2, "acpi_timer", 0)) == NULL) {
  136         device_printf(parent, "could not add acpi_timer0\n");
  137         return_VOID;
  138     }
  139     acpi_timer_dev = dev;
  140 
  141     switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
  142     case ACPI_ADR_SPACE_SYSTEM_MEMORY:
  143         rtype = SYS_RES_MEMORY;
  144         break;
  145     case ACPI_ADR_SPACE_SYSTEM_IO:
  146         rtype = SYS_RES_IOPORT;
  147         break;
  148     default:
  149         return_VOID;
  150     }
  151     rid = 0;
  152     rlen = AcpiGbl_FADT.PmTimerLength;
  153     rstart = AcpiGbl_FADT.XPmTimerBlock.Address;
  154     if (bus_set_resource(dev, rtype, rid, rstart, rlen))
  155         device_printf(dev, "couldn't set resource (%s 0x%jx+0x%jx)\n",
  156             (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen);
  157     return_VOID;
  158 }
  159 
  160 static int
  161 acpi_timer_probe(device_t dev)
  162 {
  163     char desc[40];
  164     int i, j, rid, rtype;
  165 
  166     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
  167 
  168     if (dev != acpi_timer_dev)
  169         return (ENXIO);
  170 
  171     switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
  172     case ACPI_ADR_SPACE_SYSTEM_MEMORY:
  173         rtype = SYS_RES_MEMORY;
  174         break;
  175     case ACPI_ADR_SPACE_SYSTEM_IO:
  176         rtype = SYS_RES_IOPORT;
  177         break;
  178     default:
  179         return (ENXIO);
  180     }
  181     rid = 0;
  182     acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
  183     if (acpi_timer_reg == NULL) {
  184         device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n",
  185             (rtype == SYS_RES_IOPORT) ? "port" : "mem",
  186             (u_long)AcpiGbl_FADT.XPmTimerBlock.Address);
  187         return (ENXIO);
  188     }
  189     acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
  190     acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
  191     if (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER)
  192         acpi_timer_timecounter.tc_counter_mask = 0xffffffff;
  193     else
  194         acpi_timer_timecounter.tc_counter_mask = 0x00ffffff;
  195     acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
  196     acpi_timer_timecounter.tc_flags = TC_FLAGS_SUSPEND_SAFE;
  197     if (testenv("debug.acpi.timer_test"))
  198         acpi_timer_boot_test();
  199 
  200     /*
  201      * If all tests of the counter succeed, use the ACPI-fast method.  If
  202      * at least one failed, default to using the safe routine, which reads
  203      * the timer multiple times to get a consistent value before returning.
  204      */
  205     j = 0;
  206     if (bootverbose)
  207         printf("ACPI timer:");
  208     for (i = 0; i < 10; i++)
  209         j += acpi_timer_test();
  210     if (bootverbose)
  211         printf(" -> %d\n", j);
  212     if (j == 10) {
  213         acpi_timer_timecounter.tc_name = "ACPI-fast";
  214         acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
  215         acpi_timer_timecounter.tc_quality = 900;
  216     } else {
  217         acpi_timer_timecounter.tc_name = "ACPI-safe";
  218         acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
  219         acpi_timer_timecounter.tc_quality = 850;
  220     }
  221     tc_init(&acpi_timer_timecounter);
  222 
  223     sprintf(desc, "%d-bit timer at %u.%06uMHz",
  224         (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) != 0 ? 32 : 24,
  225         acpi_timer_frequency / 1000000, acpi_timer_frequency % 1000000);
  226     device_set_desc_copy(dev, desc);
  227 
  228     /* Release the resource, we'll allocate it again during attach. */
  229     bus_release_resource(dev, rtype, rid, acpi_timer_reg);
  230     return (0);
  231 }
  232 
  233 static int
  234 acpi_timer_attach(device_t dev)
  235 {
  236     int rid, rtype;
  237 
  238     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
  239 
  240     switch (AcpiGbl_FADT.XPmTimerBlock.SpaceId) {
  241     case ACPI_ADR_SPACE_SYSTEM_MEMORY:
  242         rtype = SYS_RES_MEMORY;
  243         break;
  244     case ACPI_ADR_SPACE_SYSTEM_IO:
  245         rtype = SYS_RES_IOPORT;
  246         break;
  247     default:
  248         return (ENXIO);
  249     }
  250     rid = 0;
  251     acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
  252     if (acpi_timer_reg == NULL)
  253         return (ENXIO);
  254     acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
  255     acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
  256 
  257     /* Register suspend event handler. */
  258     if (EVENTHANDLER_REGISTER(power_suspend, acpi_timer_suspend_handler,
  259         &acpi_timer_timecounter, EVENTHANDLER_PRI_LAST) == NULL)
  260         device_printf(dev, "failed to register suspend event handler\n");
  261 
  262     return (0);
  263 }
  264 
  265 static void
  266 acpi_timer_resume_handler(struct timecounter *newtc)
  267 {
  268         struct timecounter *tc;
  269 
  270         tc = timecounter;
  271         if (tc != newtc) {
  272                 if (bootverbose)
  273                         device_printf(acpi_timer_dev,
  274                             "restoring timecounter, %s -> %s\n",
  275                             tc->tc_name, newtc->tc_name);
  276                 (void)newtc->tc_get_timecount(newtc);
  277                 (void)newtc->tc_get_timecount(newtc);
  278                 timecounter = newtc;
  279         }
  280 }
  281 
  282 static void
  283 acpi_timer_suspend_handler(struct timecounter *newtc)
  284 {
  285         struct timecounter *tc;
  286 
  287         /* Deregister existing resume event handler. */
  288         if (acpi_timer_eh != NULL) {
  289                 EVENTHANDLER_DEREGISTER(power_resume, acpi_timer_eh);
  290                 acpi_timer_eh = NULL;
  291         }
  292 
  293         if ((timecounter->tc_flags & TC_FLAGS_SUSPEND_SAFE) != 0) {
  294                 /*
  295                  * If we are using a suspend safe timecounter, don't
  296                  * save/restore it across suspend/resume.
  297                  */
  298                 return;
  299         }
  300 
  301         KASSERT(newtc == &acpi_timer_timecounter,
  302             ("acpi_timer_suspend_handler: wrong timecounter"));
  303 
  304         tc = timecounter;
  305         if (tc != newtc) {
  306                 if (bootverbose)
  307                         device_printf(acpi_timer_dev,
  308                             "switching timecounter, %s -> %s\n",
  309                             tc->tc_name, newtc->tc_name);
  310                 (void)acpi_timer_read();
  311                 (void)acpi_timer_read();
  312                 timecounter = newtc;
  313                 acpi_timer_eh = EVENTHANDLER_REGISTER(power_resume,
  314                     acpi_timer_resume_handler, tc, EVENTHANDLER_PRI_LAST);
  315         }
  316 }
  317 
  318 /*
  319  * Fetch current time value from reliable hardware.
  320  */
  321 static u_int
  322 acpi_timer_get_timecount(struct timecounter *tc)
  323 {
  324     return (acpi_timer_read());
  325 }
  326 
  327 /*
  328  * Fetch current time value from hardware that may not correctly
  329  * latch the counter.  We need to read until we have three monotonic
  330  * samples and then use the middle one, otherwise we are not protected
  331  * against the fact that the bits can be wrong in two directions.  If
  332  * we only cared about monosity, two reads would be enough.
  333  */
  334 static u_int
  335 acpi_timer_get_timecount_safe(struct timecounter *tc)
  336 {
  337     u_int u1, u2, u3;
  338 
  339     u2 = acpi_timer_read();
  340     u3 = acpi_timer_read();
  341     do {
  342         u1 = u2;
  343         u2 = u3;
  344         u3 = acpi_timer_read();
  345     } while (u1 > u2 || u2 > u3);
  346 
  347     return (u2);
  348 }
  349 
  350 /*
  351  * Timecounter freqency adjustment interface.
  352  */ 
  353 static int
  354 acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
  355 {
  356     int error;
  357     u_int freq;
  358  
  359     if (acpi_timer_timecounter.tc_frequency == 0)
  360         return (EOPNOTSUPP);
  361     freq = acpi_timer_frequency;
  362     error = sysctl_handle_int(oidp, &freq, 0, req);
  363     if (error == 0 && req->newptr != NULL) {
  364         acpi_timer_frequency = freq;
  365         acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
  366     }
  367 
  368     return (error);
  369 }
  370  
  371 SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
  372     0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "ACPI timer frequency");
  373 
  374 /*
  375  * Some ACPI timers are known or believed to suffer from implementation
  376  * problems which can lead to erroneous values being read.  This function
  377  * tests for consistent results from the timer and returns 1 if it believes
  378  * the timer is consistent, otherwise it returns 0.
  379  *
  380  * It appears the cause is that the counter is not latched to the PCI bus
  381  * clock when read:
  382  *
  383  * ] 20. ACPI Timer Errata
  384  * ]
  385  * ]   Problem: The power management timer may return improper result when
  386  * ]   read. Although the timer value settles properly after incrementing,
  387  * ]   while incrementing there is a 3nS window every 69.8nS where the
  388  * ]   timer value is indeterminate (a 4.2% chance that the data will be
  389  * ]   incorrect when read). As a result, the ACPI free running count up
  390  * ]   timer specification is violated due to erroneous reads.  Implication:
  391  * ]   System hangs due to the "inaccuracy" of the timer when used by
  392  * ]   software for time critical events and delays.
  393  * ]
  394  * ] Workaround: Read the register twice and compare.
  395  * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
  396  * ] in the PIIX4M.
  397  */
  398 #define N 2000
  399 static int
  400 acpi_timer_test()
  401 {
  402     uint32_t last, this;
  403     int delta, max, max2, min, n;
  404     register_t s;
  405 
  406     min = INT32_MAX;
  407     max = max2 = 0;
  408 
  409     /* Test the timer with interrupts disabled to get accurate results. */
  410     s = intr_disable();
  411     last = acpi_timer_read();
  412     for (n = 0; n < N; n++) {
  413         this = acpi_timer_read();
  414         delta = acpi_TimerDelta(this, last);
  415         if (delta > max) {
  416             max2 = max;
  417             max = delta;
  418         } else if (delta > max2)
  419             max2 = delta;
  420         if (delta < min)
  421             min = delta;
  422         last = this;
  423     }
  424     intr_restore(s);
  425 
  426     delta = max2 - min;
  427     if ((max - min > 8 || delta > 3) && vm_guest == VM_GUEST_NO)
  428         n = 0;
  429     else if (min < 0 || max == 0 || max2 == 0)
  430         n = 0;
  431     else
  432         n = 1;
  433     if (bootverbose)
  434         printf(" %d/%d", n, delta);
  435 
  436     return (n);
  437 }
  438 #undef N
  439 
  440 /*
  441  * Test harness for verifying ACPI timer behaviour.
  442  * Boot with debug.acpi.timer_test set to invoke this.
  443  */
  444 static void
  445 acpi_timer_boot_test(void)
  446 {
  447     uint32_t u1, u2, u3;
  448 
  449     u1 = acpi_timer_read();
  450     u2 = acpi_timer_read();
  451     u3 = acpi_timer_read();
  452 
  453     device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
  454     for (;;) {
  455         /*
  456          * The failure case is where u3 > u1, but u2 does not fall between
  457          * the two, ie. it contains garbage.
  458          */
  459         if (u3 > u1) {
  460             if (u2 < u1 || u2 > u3)
  461                 device_printf(acpi_timer_dev,
  462                               "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
  463                               u1, u2, u3);
  464         }
  465         u1 = u2;
  466         u2 = u3;
  467         u3 = acpi_timer_read();
  468     }
  469 }

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