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/* -*- Mode:C; c-basic-offset:4; tab-width:4 -*-
****************************************************************************
* (C) 2003 - Rolf Neugebauer - Intel Research Cambridge
****************************************************************************
*
* File: time.c
* Author: Rolf Neugebauer (neugebar@dcs.gla.ac.uk)
* Changes:
*
* Date: Jul 2003
*
* Environment: Xen Minimal OS
* Description: Simple time and timer functions
*
****************************************************************************
* $Id: c-insert.c,v 1.7 2002/11/08 16:04:34 rn Exp $
****************************************************************************
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <os.h>
#include <types.h>
#include <hypervisor.h>
#include <events.h>
#include <time.h>
#include <lib.h>
/************************************************************************
* Time functions
*************************************************************************/
static unsigned int rdtsc_bitshift;
static u32 st_scale_f; /* convert ticks -> usecs */
static u32 st_scale_i; /* convert ticks -> usecs */
/* These are peridically updated in shared_info, and then copied here. */
static u32 shadow_tsc_stamp;
static s64 shadow_system_time;
static u32 shadow_time_version;
static struct timeval shadow_tv;
#ifndef rmb
#define rmb() __asm__ __volatile__ ("lock; addl $0,0(%%esp)": : :"memory")
#endif
#define HANDLE_USEC_OVERFLOW(_tv) \
do { \
while ( (_tv).tv_usec >= 1000000 ) \
{ \
(_tv).tv_usec -= 1000000; \
(_tv).tv_sec++; \
} \
} while ( 0 )
static void get_time_values_from_xen(void)
{
do {
shadow_time_version = HYPERVISOR_shared_info->time_version2;
rmb();
shadow_tv.tv_sec = HYPERVISOR_shared_info->wc_sec;
shadow_tv.tv_usec = HYPERVISOR_shared_info->wc_usec;
shadow_tsc_stamp = HYPERVISOR_shared_info->tsc_timestamp;
shadow_system_time = HYPERVISOR_shared_info->system_time;
rmb();
}
while ( shadow_time_version != HYPERVISOR_shared_info->time_version1 );
}
#define TIME_VALUES_UP_TO_DATE \
(shadow_time_version == HYPERVISOR_shared_info->time_version2)
static inline unsigned long get_time_delta_usecs(void)
{
s32 delta_tsc;
u32 low;
u64 delta, tsc;
rdtscll(tsc);
low = (u32)(tsc >> rdtsc_bitshift);
delta_tsc = (s32)(low - shadow_tsc_stamp);
if ( unlikely(delta_tsc < 0) ) delta_tsc = 0;
delta = ((u64)delta_tsc * st_scale_f);
delta >>= 32;
delta += ((u64)delta_tsc * st_scale_i);
return (unsigned long)delta;
}
void gettimeofday(struct timeval *tv)
{
struct timeval _tv;
do {
get_time_values_from_xen();
_tv.tv_usec = get_time_delta_usecs();
_tv.tv_sec = shadow_tv.tv_sec;
_tv.tv_usec += shadow_tv.tv_usec;
}
while ( unlikely(!TIME_VALUES_UP_TO_DATE) );
HANDLE_USEC_OVERFLOW(_tv);
*tv = _tv;
}
static void timer_handler(int ev, struct pt_regs *regs)
{
static int i;
struct timeval tv;
i++;
if (i >= 1000) {
gettimeofday(&tv);
printf("T(s=%ld us=%ld)\n", tv.tv_sec, tv.tv_usec);
i = 0;
}
}
void init_time(void)
{
u64 __cpu_khz, cpu_freq, scale;
unsigned long cpu_khz;
__cpu_khz = HYPERVISOR_shared_info->cpu_freq;
cpu_khz = (u32) (__cpu_khz/1000);
rdtsc_bitshift = HYPERVISOR_shared_info->rdtsc_bitshift;
cpu_freq = HYPERVISOR_shared_info->cpu_freq;
scale = 1000000LL << (32 + rdtsc_bitshift);
scale /= cpu_freq;
st_scale_f = scale & 0xffffffff;
st_scale_i = scale >> 32;
printk("Xen reported: %lu.%03lu MHz processor.\n",
cpu_khz / 1000, cpu_khz % 1000);
add_ev_action(EV_TIMER, &timer_handler);
enable_ev_action(EV_TIMER);
enable_hypervisor_event(EV_TIMER);
}
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