xref: /titanic_53/usr/src/boot/sys/boot/arm/at91/libat91/delay.c (revision 4a5d661a82b942b6538acd26209d959ce98b593a)
1 /*-
2  * Copyright (c) 2006 M. Warner Losh.  All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23  *
24  * This software is derived from software provide by Kwikbyte who specifically
25  * disclaimed copyright on the code.
26  *
27  * $FreeBSD$
28  */
29 
30 #include "at91rm9200.h"
31 #include "spi_flash.h"
32 #include "lib.h"
33 
34 void
Delay(int us)35 Delay(int us)
36 {
37 	unsigned later, now;
38 
39 	now = AT91C_BASE_ST->ST_CRTR;
40 	later = (now + us / 25 + 1) & AT91C_ST_CRTV;
41 	while (later != AT91C_BASE_ST->ST_CRTR)
42 		continue;
43 }
44