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/*
* Copyright (C) 2010 Piotr Jaroszyński <p.jaroszynski@gmail.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*/
FILE_LICENCE(GPL2_OR_LATER);
#include <stddef.h>
#include <ipxe/timer.h>
#include <linux_api.h>
/** @file
*
* iPXE timer API for linux
*
*/
/**
* Delay for a fixed number of microseconds
*
* @v usecs Number of microseconds for which to delay
*/
static void linux_udelay(unsigned long usecs)
{
linux_usleep(usecs);
}
/**
* Get number of ticks per second
*
* @ret ticks_per_sec Number of ticks per second
*/
static unsigned long linux_ticks_per_sec(void)
{
return 1000;
}
/**
* Get current system time in ticks
*
* linux doesn't provide an easy access to jiffies so implement it by measuring
* the time since the first call to this function.
*
* Since this function is used to seed the (non-cryptographic) random
* number generator, we round the start time down to the nearest whole
* second. This minimises the chances of generating identical RNG
* sequences (and hence identical TCP port numbers, etc) on
* consecutive invocations of iPXE.
*
* @ret ticks Current time, in ticks
*/
static unsigned long linux_currticks(void)
{
static struct timeval start;
static int initialized = 0;
if (! initialized) {
linux_gettimeofday(&start, NULL);
initialized = 1;
}
struct timeval now;
linux_gettimeofday(&now, NULL);
unsigned long ticks = (now.tv_sec - start.tv_sec) * linux_ticks_per_sec();
ticks += now.tv_usec / (long)(1000000 / linux_ticks_per_sec());
return ticks;
}
PROVIDE_TIMER(linux, udelay, linux_udelay);
PROVIDE_TIMER(linux, currticks, linux_currticks);
PROVIDE_TIMER(linux, ticks_per_sec, linux_ticks_per_sec);
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