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