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Annotation of qemu/roms/SLOF/clients/net-snk/kernel/timer.c, revision 1.1

1.1     ! root        1: /******************************************************************************
        !             2:  * Copyright (c) 2004, 2008 IBM Corporation
        !             3:  * All rights reserved.
        !             4:  * This program and the accompanying materials
        !             5:  * are made available under the terms of the BSD License
        !             6:  * which accompanies this distribution, and is available at
        !             7:  * http://www.opensource.org/licenses/bsd-license.php
        !             8:  *
        !             9:  * Contributors:
        !            10:  *     IBM Corporation - initial implementation
        !            11:  *****************************************************************************/
        !            12: #include <types.h>
        !            13: 
        !            14: //*******************************************************************
        !            15: // variable "tb_freq" contains the frequency in Hz
        !            16: // and is read from the device tree (setup by LLFW) in "init.c"
        !            17: uint64_t tb_freq;
        !            18: 
        !            19: //-------------------------------------------------------------------
        !            20: // Read the current timebase
        !            21: uint64_t get_time(void)
        !            22: {
        !            23:     uint64_t act;
        !            24: 
        !            25:     __asm__ __volatile__( 
        !            26:         "0:     mftbu   %0 ;\
        !            27:                 mftbl   %%r0 ; \
        !            28:                 mftbu   %%r4 ; \
        !            29:                 cmpw    %0,%%r4 ; \
        !            30:                 bne     0b; \
        !            31:                 sldi    %0,%0,32; \
        !            32:                 or      %0,%0,%%r0"
        !            33:         : "=r"(act)
        !            34:         : /* no inputs */
        !            35:         : "r0", "r4");
        !            36:     return act;
        !            37: }
        !            38: 
        !            39: //-------------------------------------------------------------------
        !            40: // wait for ticks/scale timebase ticks
        !            41: void wait_ticks(uint64_t ticks)
        !            42: {
        !            43:         uint64_t timeout = get_time() + ticks;
        !            44:         while (get_time() < timeout) {
        !            45:                 unsigned int i;
        !            46:                 for (i = 1000; i > 0; i--)
        !            47:                         __asm__ __volatile__ ("" : : : "memory");
        !            48:         }
        !            49: }
        !            50: 
        !            51: //-------------------------------------------------------------------
        !            52: // wait for (at least) usecs microseconds
        !            53: void udelay(unsigned int usecs)
        !            54: {
        !            55:         // first multiply the usec with timebase and then devide
        !            56:         // because 1.000.000 is relatively huge compared to usecs
        !            57:         wait_ticks((usecs*tb_freq)/1000000);
        !            58: }
        !            59: 
        !            60: //-------------------------------------------------------------------
        !            61: // wait for (at least) msecs milliseconds
        !            62: void mdelay(unsigned int msecs)
        !            63: {
        !            64:         // first multiply the msec and timebase and then devide
        !            65:         // because 1.000 is relatively huge compared to msecs
        !            66:         wait_ticks((msecs*tb_freq)/1000);
        !            67: }

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