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			141 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			141 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * (C) Copyright 2007-2008
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 * Stelian Pop <stelian.pop@leadtechdesign.com>
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 * Lead Tech Design <www.leadtechdesign.com>
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 *
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 * See file CREDITS for list of people who contributed to this
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 * project.
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 *
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 * This program is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU General Public License as
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 * published by the Free Software Foundation; either version 2 of
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 * the License, or (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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 * MA 02111-1307 USA
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 */
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#include <common.h>
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#include <asm/arch/hardware.h>
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#include <asm/arch/at91_pit.h>
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#include <asm/arch/at91_pmc.h>
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#include <asm/arch/clk.h>
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#include <asm/arch/io.h>
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#include <div64.h>
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/*
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 * We're using the AT91CAP9/SAM9 PITC in 32 bit mode, by
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 * setting the 20 bit counter period to its maximum (0xfffff).
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 */
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#define TIMER_LOAD_VAL	0xfffff
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#define READ_RESET_TIMER at91_sys_read(AT91_PIT_PIVR)
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#define READ_TIMER at91_sys_read(AT91_PIT_PIIR)
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static ulong timestamp;
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static ulong lastinc;
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static ulong timer_freq;
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static inline unsigned long long tick_to_time(unsigned long long tick)
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{
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	tick *= CONFIG_SYS_HZ;
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	do_div(tick, timer_freq);
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	return tick;
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}
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static inline unsigned long long usec_to_tick(unsigned long long usec)
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{
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	usec *= timer_freq;
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	do_div(usec, 1000000);
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	return usec;
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}
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/* nothing really to do with interrupts, just starts up a counter. */
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int timer_init(void)
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{
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	/*
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	 * Enable PITC Clock
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	 * The clock is already enabled for system controller in boot
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	 */
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	at91_sys_write(AT91_PMC_PCER, 1 << AT91_ID_SYS);
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	/* Enable PITC */
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	at91_sys_write(AT91_PIT_MR, TIMER_LOAD_VAL | AT91_PIT_PITEN);
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	reset_timer_masked();
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	timer_freq = get_mck_clk_rate() >> 4;
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	return 0;
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}
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/*
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 * timer without interrupts
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 */
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unsigned long long get_ticks(void)
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{
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	ulong now = READ_TIMER;
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	if (now >= lastinc)	/* normal mode (non roll) */
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		/* move stamp forward with absolut diff ticks */
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		timestamp += (now - lastinc);
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	else			/* we have rollover of incrementer */
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		timestamp += (0xFFFFFFFF - lastinc) + now;
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	lastinc = now;
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	return timestamp;
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}
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void reset_timer_masked(void)
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{
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	/* reset time */
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	lastinc = READ_TIMER; /* capture current incrementer value time */
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	timestamp = 0; /* start "advancing" time stamp from 0 */
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}
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ulong get_timer_masked(void)
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{
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	return tick_to_time(get_ticks());
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}
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void udelay(unsigned long usec)
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{
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	unsigned long long tmp;
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	ulong tmo;
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	tmo = usec_to_tick(usec);
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	tmp = get_ticks() + tmo;	/* get current timestamp */
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	while (get_ticks() < tmp)	/* loop till event */
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		 /*NOP*/;
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}
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void reset_timer(void)
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{
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	reset_timer_masked();
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}
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ulong get_timer(ulong base)
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{
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	return get_timer_masked () - base;
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}
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/*
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 * This function is derived from PowerPC code (timebase clock frequency).
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 * On ARM it returns the number of timer ticks per second.
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 */
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ulong get_tbclk(void)
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{
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	ulong tbclk;
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	tbclk = CONFIG_SYS_HZ;
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	return tbclk;
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}
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