sys/dev/ic/acpipmtimer.c

   1 /* $NetBSD: acpipmtimer.c,v 1.7 2009/05/12 14:25:17 cegger Exp $ */
   2
   3 #include <sys/cdefs.h>
   4 __KERNEL_RCSID(0, "$NetBSD: acpipmtimer.c,v 1.7 2009/05/12 14:25:17 cegger Exp $");
   5
   6 #include <sys/types.h>
   7
   8 #include <sys/systm.h>
   9 #include <sys/device.h>
  10 #include <sys/malloc.h>
  11 #include <sys/bus.h>
  12 #include <sys/time.h>
  13 #include <sys/timetc.h>
  14
  15 #include <dev/ic/acpipmtimer.h>
  16
  17 #define ACPI_PM_TIMER_FREQUENCY 3579545
  18
  19 struct hwtc {
  20         struct timecounter tc;
  21         bus_space_tag_t t;
  22         bus_space_handle_t h;
  23         bus_size_t off;
  24 };
  25
  26 static u_int acpihwtimer_read_safe(struct timecounter *);
  27 static u_int acpihwtimer_read_fast(struct timecounter *);
  28
  29 acpipmtimer_t
  30 acpipmtimer_attach(device_t dev,
  31                    bus_space_tag_t t, bus_space_handle_t h, bus_size_t off,
  32                    int flags)
  33 {
  34         struct hwtc *tc;
  35
  36         tc = malloc(sizeof(struct hwtc), M_DEVBUF, M_WAITOK|M_ZERO);
  37         if (tc == NULL)
  38                 return NULL;
  39
  40         tc->tc.tc_name = device_xname(dev);
  41         tc->tc.tc_frequency = ACPI_PM_TIMER_FREQUENCY;
  42         if (flags & ACPIPMT_32BIT)
  43                 tc->tc.tc_counter_mask = 0xffffffff;
  44         else
  45                 tc->tc.tc_counter_mask = 0x00ffffff;
  46         if (flags & ACPIPMT_BADLATCH) {
  47                 tc->tc.tc_get_timecount = acpihwtimer_read_safe;
  48                 tc->tc.tc_quality = 900;
  49         } else {
  50                 tc->tc.tc_get_timecount = acpihwtimer_read_fast;
  51                 tc->tc.tc_quality = 1000;
  52         }
  53
  54         tc->t = t;
  55         tc->h = h;
  56         tc->off = off;
  57
  58         tc->tc.tc_priv = tc;
  59         tc_init(&tc->tc);
  60         aprint_normal("%s: %d-bit timer\n", tc->tc.tc_name,
  61                       (flags & ACPIPMT_32BIT ? 32 : 24));
  62         return tc;
  63 }
  64
  65 int
  66 acpipmtimer_detach(acpipmtimer_t timer, int flags)
  67 {
  68         struct hwtc *tc = timer;
  69
  70         return tc_detach(&tc->tc);
  71 }
  72
  73 #define r(h) bus_space_read_4(h->t, h->h, h->off)
  74
  75 static u_int
  76 acpihwtimer_read_safe(struct timecounter *tc)
  77 {
  78         struct hwtc *h = tc->tc_priv;
  79         uint32_t t1, t2, t3;
  80
  81         t2 = r(h);
  82         t3 = r(h);
  83         do {
  84                 t1 = t2;
  85                 t2 = t3;
  86                 t3 = r(h);
  87         } while ((t1 > t2) || (t2 > t3));
  88         return (t2);
  89 }
  90
  91 static u_int
  92 acpihwtimer_read_fast(struct timecounter *tc)
  93 {
  94         struct hwtc *h = tc->tc_priv;
  95
  96         return r(h);
  97 }