inmates/lib/x86/timing.c

   1 /*
   2  * Jailhouse, a Linux-based partitioning hypervisor
   3  *
   4  * Copyright (c) Siemens AG, 2013, 2014
   5  *
   6  * Authors:
   7  *  Jan Kiszka <jan.kiszka@siemens.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  */
  12
  13 #include <inmate.h>
  14
  15 #define PM_TIMER_HZ             3579545
  16 #define PM_TIMER_OVERFLOW      ((0x1000000 * NS_PER_SEC) / PM_TIMER_HZ)
  17
  18 #define X2APIC_LVTT             0x832
  19 #define X2APIC_TMICT            0x838
  20 #define X2APIC_TMCCT            0x839
  21 #define X2APIC_TDCR             0x83e
  22
  23 static unsigned long divided_apic_freq;
  24
  25 unsigned long pm_timer_read(void)
  26 {
  27         static unsigned long last, overflows;
  28         unsigned long tmr;
  29
  30         tmr = ((inl(comm_region->pm_timer_address) & 0x00ffffff) * NS_PER_SEC)
  31                 / PM_TIMER_HZ;
  32         if (tmr < last)
  33                 overflows += PM_TIMER_OVERFLOW;
  34         last = tmr;
  35         return tmr + overflows;
  36 }
  37
  38 void delay_us(unsigned long microsecs)
  39 {
  40         unsigned long timeout = pm_timer_read() + microsecs * NS_PER_USEC;
  41
  42         while ((long)(timeout - pm_timer_read()) > 0)
  43                 cpu_relax();
  44 }
  45
  46 unsigned long apic_timer_init(unsigned int vector)
  47 {
  48         unsigned long start, end;
  49         unsigned long tmr;
  50
  51         write_msr(X2APIC_TDCR, 3);
  52
  53         start = pm_timer_read();
  54         write_msr(X2APIC_TMICT, 0xffffffff);
  55
  56         while (pm_timer_read() - start < 100 * NS_PER_MSEC)
  57                 cpu_relax();
  58
  59         end = pm_timer_read();
  60         tmr = read_msr(X2APIC_TMCCT);
  61
  62         divided_apic_freq = (0xffffffffULL - tmr) * NS_PER_SEC / (end - start);
  63
  64         write_msr(X2APIC_TMICT, 0);
  65         write_msr(X2APIC_LVTT, vector);
  66
  67         return (divided_apic_freq * 16 + 500) / 1000;
  68 }
  69
  70 void apic_timer_set(unsigned long timeout_ns)
  71 {
  72         unsigned long long ticks =
  73                 (unsigned long long)timeout_ns * divided_apic_freq;
  74         write_msr(X2APIC_TMICT, ticks / NS_PER_SEC);
  75 }