WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/time/delay.c


/*
 * Copyright (C) 2001-2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
/** @addtogroup time
 * @{
 */
 
/**
 * @file
 * @brief   Active delay function.
 */
 
#include <time/delay.h>
#include <arch/types.h>
#include <cpu.h>
#include <arch/asm.h>
#include <arch.h>
 
/** Active delay
 *
 * Delay the execution for the given number
 * of microseconds (or slightly more). The delay
 * is implemented as CPU calibrated active loop.
 *
 * @param usec Number of microseconds to sleep.
 */
void delay(uint32_t usec)
{
    ipl_t ipl;
   
    /*
     * The delay loop is calibrated for each and every
     * CPU in the system. Therefore it is necessary to
     * call interrupts_disable() before calling the
     * asm_delay_loop().
     */
    ipl = interrupts_disable();
    asm_delay_loop(usec * CPU->delay_loop_const);
    interrupts_restore(ipl);
}
 
/** @}
 */
 

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/time/delay.c – Rev 1757 → 1780

Rev 1757		Rev 1780
1	/*	1	/*
2	* Copyright (C) 2001-2004 Jakub Jermar	2	* Copyright (C) 2001-2004 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/** @addtogroup time	29	/** @addtogroup time
30	* @{	30	* @{
31	*/	31	*/
32		32
33	/**	33	/**
34	* @file	34	* @file
35	* @brief Active delay function.	35	* @brief Active delay function.
36	*/	36	*/
37		37
38	#include <time/delay.h>	38	#include <time/delay.h>
39	#include <arch/types.h>	39	#include <arch/types.h>
40	#include <cpu.h>	40	#include <cpu.h>
41	#include <arch/asm.h>	41	#include <arch/asm.h>
42	#include <arch.h>	42	#include <arch.h>
43		43
44	/** Active delay	44	/** Active delay
45	*	45	*
46	* Delay the execution for the given number	46	* Delay the execution for the given number
47	* of microseconds (or slightly more). The delay	47	* of microseconds (or slightly more). The delay
48	* is implemented as CPU calibrated active loop.	48	* is implemented as CPU calibrated active loop.
49	*	49	*
50	* @param usec Number of microseconds to sleep.	50	* @param usec Number of microseconds to sleep.
51	*/	51	*/
52	void delay(__u32 usec)	52	void delay(uint32_t usec)
53	{	53	{
54	ipl_t ipl;	54	ipl_t ipl;
55		55
56	/*	56	/*
57	* The delay loop is calibrated for each and every	57	* The delay loop is calibrated for each and every
58	* CPU in the system. Therefore it is necessary to	58	* CPU in the system. Therefore it is necessary to
59	* call interrupts_disable() before calling the	59	* call interrupts_disable() before calling the
60	* asm_delay_loop().	60	* asm_delay_loop().
61	*/	61	*/
62	ipl = interrupts_disable();	62	ipl = interrupts_disable();
63	asm_delay_loop(usec * CPU->delay_loop_const);	63	asm_delay_loop(usec * CPU->delay_loop_const);
64	interrupts_restore(ipl);	64	interrupts_restore(ipl);
65	}	65	}
66		66
67	/** @}	67	/** @}
68	*/	68	*/
69		69