delay.c

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00001 /*
00002  * Copyright (C) 2001-2004 Jakub Jermar
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  *
00009  * - Redistributions of source code must retain the above copyright
00010  *   notice, this list of conditions and the following disclaimer.
00011  * - Redistributions in binary form must reproduce the above copyright
00012  *   notice, this list of conditions and the following disclaimer in the
00013  *   documentation and/or other materials provided with the distribution.
00014  * - The name of the author may not be used to endorse or promote products
00015  *   derived from this software without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
00018  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
00019  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
00020  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
00021  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
00022  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
00023  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
00024  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
00025  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
00026  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00027  */
00028 
00038 #include <time/delay.h>
00039 #include <arch/types.h>
00040 #include <cpu.h>
00041 #include <arch/asm.h>
00042 #include <arch.h>
00043 
00052 void delay(__u32 usec)
00053 {
00054         ipl_t ipl;
00055         
00056         /* 
00057          * The delay loop is calibrated for each and every
00058          * CPU in the system. Therefore it is necessary to
00059          * call interrupts_disable() before calling the
00060          * asm_delay_loop().
00061          */
00062         ipl = interrupts_disable();
00063         asm_delay_loop(usec * CPU->delay_loop_const);
00064         interrupts_restore(ipl);
00065 }
00066 

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