inmates/lib/x86/timing.c

   1 /*
   2  * Jailhouse, a Linux-based partitioning hypervisor
   3  *
   4  * Copyright (c) Siemens AG, 2013, 2014
   5  * Copyright (c) Valentine Sinitsyn, 2014
   6  *
   7  * Authors:
   8  *  Jan Kiszka <jan.kiszka@siemens.com>
   9  *  Valentine Sinitsyn <valentine.sinitsyn@gmail.com>
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2.  See
  12  * the COPYING file in the top-level directory.
  13  */
  14
  15 #include <inmate.h>
  16
  17 #define PM_TIMER_HZ             3579545
  18
  19 #define X2APIC_LVTT             0x832
  20 #define X2APIC_TMICT            0x838
  21 #define X2APIC_TMCCT            0x839
  22 #define X2APIC_TDCR             0x83e
  23
  24 static unsigned long divided_apic_freq;
  25 static unsigned long pm_timer_overflow;
  26
  27 void pm_timer_init(void)
  28 {
  29         /* Initialize pm_timer overflow value, as per ACPI 5.0, Sect. 5.2.9. */
  30         if (comm_region->pm_timer_val_ext)
  31                 pm_timer_overflow =
  32                         ((0x100000000 * 1000000000ULL) / PM_TIMER_HZ);
  33         else
  34                 pm_timer_overflow =
  35                         ((0x1000000 * 1000000000ULL) / PM_TIMER_HZ);
  36 }
  37
  38 unsigned long pm_timer_read(void)
  39 {
  40         static unsigned long last, overflows;
  41         unsigned long tmr;
  42
  43         tmr = (inl(comm_region->pm_timer_address) * NS_PER_SEC) / PM_TIMER_HZ;
  44         if (tmr < last)
  45                 overflows += pm_timer_overflow;
  46         last = tmr;
  47         return tmr + overflows;
  48 }
  49
  50 void delay_us(unsigned long microsecs)
  51 {
  52         unsigned long timeout = pm_timer_read() + microsecs * NS_PER_USEC;
  53
  54         while ((long)(timeout - pm_timer_read()) > 0)
  55                 cpu_relax();
  56 }
  57
  58 unsigned long apic_timer_init(unsigned int vector)
  59 {
  60         unsigned long start, end;
  61         unsigned long tmr;
  62
  63         write_msr(X2APIC_TDCR, 3);
  64
  65         start = pm_timer_read();
  66         write_msr(X2APIC_TMICT, 0xffffffff);
  67
  68         while (pm_timer_read() - start < 100 * NS_PER_MSEC)
  69                 cpu_relax();
  70
  71         end = pm_timer_read();
  72         tmr = read_msr(X2APIC_TMCCT);
  73
  74         divided_apic_freq = (0xffffffffULL - tmr) * NS_PER_SEC / (end - start);
  75
  76         write_msr(X2APIC_TMICT, 0);
  77         write_msr(X2APIC_LVTT, vector);
  78
  79         return (divided_apic_freq * 16 + 500) / 1000;
  80 }
  81
  82 void apic_timer_set(unsigned long timeout_ns)
  83 {
  84         unsigned long long ticks =
  85                 (unsigned long long)timeout_ns * divided_apic_freq;
  86         write_msr(X2APIC_TMICT, ticks / NS_PER_SEC);
  87 }