04e554807c
Change-Id: Ibead64ce2e901dede2ddd1b86088b88f2350ce92 Signed-off-by: Duy Truong <dtruong@codeaurora.org>
91 lines
1.9 KiB
C
91 lines
1.9 KiB
C
/*
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* Originally from linux/arch/arm/lib/delay.S
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*
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* Copyright (C) 1995, 1996 Russell King
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* Copyright (c) 2010, The Linux Foundation. All rights reserved.
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* Copyright (C) 1993 Linus Torvalds
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* Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
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* Copyright (C) 2005-2006 Atmel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/timex.h>
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/*
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* Oh, if only we had a cycle counter...
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*/
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void delay_loop(unsigned long loops)
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{
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asm volatile(
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"1: subs %0, %0, #1 \n"
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" bhi 1b \n"
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: /* No output */
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: "r" (loops)
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);
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}
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#ifdef ARCH_HAS_READ_CURRENT_TIMER
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/*
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* Assuming read_current_timer() is monotonically increasing
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* across calls.
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*/
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void read_current_timer_delay_loop(unsigned long loops)
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{
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unsigned long bclock, now;
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read_current_timer(&bclock);
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do {
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read_current_timer(&now);
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} while ((now - bclock) < loops);
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}
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#endif
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static void (*delay_fn)(unsigned long) = delay_loop;
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void set_delay_fn(void (*fn)(unsigned long))
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{
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delay_fn = fn;
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}
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/*
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* loops = usecs * HZ * loops_per_jiffy / 1000000
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*/
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void __delay(unsigned long loops)
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{
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delay_fn(loops);
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}
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EXPORT_SYMBOL(__delay);
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/*
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* 0 <= xloops <= 0x7fffff06
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* loops_per_jiffy <= 0x01ffffff (max. 3355 bogomips)
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*/
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void __const_udelay(unsigned long xloops)
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{
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unsigned long lpj;
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unsigned long loops;
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xloops >>= 14; /* max = 0x01ffffff */
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lpj = loops_per_jiffy >> 10; /* max = 0x0001ffff */
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loops = lpj * xloops; /* max = 0x00007fff */
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loops >>= 6; /* max = 2^32-1 */
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if (loops)
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__delay(loops);
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}
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EXPORT_SYMBOL(__const_udelay);
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/*
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* usecs <= 2000
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* HZ <= 1000
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*/
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void __udelay(unsigned long usecs)
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{
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__const_udelay(usecs * ((2199023UL*HZ)>>11));
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}
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EXPORT_SYMBOL(__udelay);
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