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Annotation of qemu/roms/ipxe/src/interface/linux/linux_timer.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (C) 2010 Piotr Jaroszyński <[email protected]>
        !             3:  *
        !             4:  * This program is free software; you can redistribute it and/or
        !             5:  * modify it under the terms of the GNU General Public License as
        !             6:  * published by the Free Software Foundation; either version 2 of the
        !             7:  * License, or any later version.
        !             8:  *
        !             9:  * This program is distributed in the hope that it will be useful, but
        !            10:  * WITHOUT ANY WARRANTY; without even the implied warranty of
        !            11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
        !            12:  * General Public License for more details.
        !            13:  *
        !            14:  * You should have received a copy of the GNU General Public License
        !            15:  * along with this program; if not, write to the Free Software
        !            16:  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
        !            17:  */
        !            18: 
        !            19: FILE_LICENCE(GPL2_OR_LATER);
        !            20: 
        !            21: #include <ipxe/timer.h>
        !            22: 
        !            23: #include <linux_api.h>
        !            24: 
        !            25: /** @file
        !            26:  *
        !            27:  * iPXE timer API for linux
        !            28:  *
        !            29:  */
        !            30: 
        !            31: /**
        !            32:  * Delay for a fixed number of microseconds
        !            33:  *
        !            34:  * @v usecs            Number of microseconds for which to delay
        !            35:  */
        !            36: static void linux_udelay(unsigned long usecs)
        !            37: {
        !            38:        linux_usleep(usecs);
        !            39: }
        !            40: 
        !            41: /**
        !            42:  * Get number of ticks per second
        !            43:  *
        !            44:  * @ret ticks_per_sec  Number of ticks per second
        !            45:  */
        !            46: static unsigned long linux_ticks_per_sec(void)
        !            47: {
        !            48:        return 1000;
        !            49: }
        !            50: 
        !            51: /**
        !            52:  * Get current system time in ticks
        !            53:  *
        !            54:  * linux doesn't provide an easy access to jiffies so implement it by measuring
        !            55:  * the time since the first call to this function.
        !            56:  *
        !            57:  * @ret ticks          Current time, in ticks
        !            58:  */
        !            59: static unsigned long linux_currticks(void)
        !            60: {
        !            61:        static struct timeval start;
        !            62:        static int initialized = 0;
        !            63: 
        !            64:        if (! initialized) {
        !            65:                linux_gettimeofday(&start, NULL);
        !            66:                initialized = 1;
        !            67:        }
        !            68: 
        !            69:        struct timeval now;
        !            70:        linux_gettimeofday(&now, NULL);
        !            71: 
        !            72:        unsigned long ticks = (now.tv_sec - start.tv_sec) * linux_ticks_per_sec();
        !            73:        ticks += (now.tv_usec - start.tv_usec) / (long)(1000000 / linux_ticks_per_sec());
        !            74: 
        !            75:        return ticks;
        !            76: }
        !            77: 
        !            78: PROVIDE_TIMER(linux, udelay, linux_udelay);
        !            79: PROVIDE_TIMER(linux, currticks, linux_currticks);
        !            80: PROVIDE_TIMER(linux, ticks_per_sec, linux_ticks_per_sec);

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