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 static unsigned long pm_timer_last[SMP_MAX_CPUS];
  25 static unsigned long pm_timer_overflows[SMP_MAX_CPUS];
  26
  27 unsigned long pm_timer_read(void)
  28 {
  29         unsigned int cpu = cpu_id();
  30         unsigned long tmr;
  31
  32         tmr = ((inl(comm_region->pm_timer_address) & 0x00ffffff) * NS_PER_SEC)
  33                 / PM_TIMER_HZ;
  34         if (tmr < pm_timer_last[cpu])
  35                 pm_timer_overflows[cpu] += PM_TIMER_OVERFLOW;
  36         pm_timer_last[cpu] = tmr;
  37         return tmr + pm_timer_overflows[cpu];
  38 }
  39
  40 void delay_us(unsigned long microsecs)
  41 {
  42         unsigned long timeout = pm_timer_read() + microsecs * NS_PER_USEC;
  43
  44         while ((long)(timeout - pm_timer_read()) > 0)
  45                 cpu_relax();
  46 }
  47
  48 unsigned long apic_timer_init(unsigned int vector)
  49 {
  50         unsigned long start, end;
  51         unsigned long tmr;
  52
  53         write_msr(X2APIC_TDCR, 3);
  54
  55         start = pm_timer_read();
  56         write_msr(X2APIC_TMICT, 0xffffffff);
  57
  58         while (pm_timer_read() - start < 100 * NS_PER_MSEC)
  59                 cpu_relax();
  60
  61         end = pm_timer_read();
  62         tmr = read_msr(X2APIC_TMCCT);
  63
  64         divided_apic_freq = (0xffffffffULL - tmr) * NS_PER_SEC / (end - start);
  65
  66         write_msr(X2APIC_TMICT, 0);
  67         write_msr(X2APIC_LVTT, vector);
  68
  69         return (divided_apic_freq * 16 + 500) / 1000;
  70 }
  71
  72 void apic_timer_set(unsigned long timeout_ns)
  73 {
  74         unsigned long long ticks =
  75                 (unsigned long long)timeout_ns * divided_apic_freq;
  76         write_msr(X2APIC_TMICT, ticks / NS_PER_SEC);
  77 }