169 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			169 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
/*
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 * Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
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 * Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved.
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 *
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 * (C) Copyright 2008
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 * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
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 *
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 * (C) Copyright 2004
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 * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
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 *
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 * (C) Copyright 2002-2004
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 * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
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 *
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 * (C) Copyright 2003
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 * Texas Instruments <www.ti.com>
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 *
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 * (C) Copyright 2002
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 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
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 * Marius Groeger <mgroeger@sysgo.de>
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 *
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 * (C) Copyright 2002
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 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
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 * Alex Zuepke <azu@sysgo.de>
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 *
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 * SPDX-License-Identifier:	GPL-2.0+
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 */
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#include <common.h>
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#include <div64.h>
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#include <asm/io.h>
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#include <asm/arch/hardware.h>
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#include <asm/arch/clk.h>
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DECLARE_GLOBAL_DATA_PTR;
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struct scu_timer {
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	u32 load; /* Timer Load Register */
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	u32 counter; /* Timer Counter Register */
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	u32 control; /* Timer Control Register */
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};
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static struct scu_timer *timer_base =
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			      (struct scu_timer *)ZYNQ_SCUTIMER_BASEADDR;
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#define SCUTIMER_CONTROL_PRESCALER_MASK	0x0000FF00 /* Prescaler */
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#define SCUTIMER_CONTROL_PRESCALER_SHIFT	8
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#define SCUTIMER_CONTROL_AUTO_RELOAD_MASK	0x00000002 /* Auto-reload */
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#define SCUTIMER_CONTROL_ENABLE_MASK		0x00000001 /* Timer enable */
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#define TIMER_LOAD_VAL 0xFFFFFFFF
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#define TIMER_PRESCALE 255
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int timer_init(void)
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{
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	const u32 emask = SCUTIMER_CONTROL_AUTO_RELOAD_MASK |
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			(TIMER_PRESCALE << SCUTIMER_CONTROL_PRESCALER_SHIFT) |
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			SCUTIMER_CONTROL_ENABLE_MASK;
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	gd->arch.timer_rate_hz = (gd->cpu_clk / 2) / (TIMER_PRESCALE + 1);
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	/* Load the timer counter register */
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	writel(0xFFFFFFFF, &timer_base->load);
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	/*
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	 * Start the A9Timer device
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	 * Enable Auto reload mode, Clear prescaler control bits
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	 * Set prescaler value, Enable the decrementer
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	 */
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	clrsetbits_le32(&timer_base->control, SCUTIMER_CONTROL_PRESCALER_MASK,
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								emask);
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	/* Reset time */
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	gd->arch.lastinc = readl(&timer_base->counter) /
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				(gd->arch.timer_rate_hz / CONFIG_SYS_HZ);
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	gd->arch.tbl = 0;
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	return 0;
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}
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/*
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 * This function is derived from PowerPC code (read timebase as long long).
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 * On ARM it just returns the timer value.
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 */
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ulong get_timer_masked(void)
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{
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	ulong now;
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	now = readl(&timer_base->counter) /
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			(gd->arch.timer_rate_hz / CONFIG_SYS_HZ);
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	if (gd->arch.lastinc >= now) {
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		/* Normal mode */
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		gd->arch.tbl += gd->arch.lastinc - now;
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	} else {
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		/* We have an overflow ... */
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		gd->arch.tbl += gd->arch.lastinc + (TIMER_LOAD_VAL /
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				(gd->arch.timer_rate_hz / CONFIG_SYS_HZ)) -
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				now + 1;
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	}
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	gd->arch.lastinc = now;
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	return gd->arch.tbl;
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}
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void __udelay(unsigned long usec)
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{
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	u32 countticks;
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	u32 timeend;
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	u32 timediff;
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	u32 timenow;
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	if (usec == 0)
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		return;
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	countticks = lldiv(((unsigned long long)gd->arch.timer_rate_hz * usec),
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			   1000000);
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	/* decrementing timer */
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	timeend = readl(&timer_base->counter) - countticks;
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#if TIMER_LOAD_VAL != 0xFFFFFFFF
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	/* do not manage multiple overflow */
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	if (countticks >= TIMER_LOAD_VAL)
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		countticks = TIMER_LOAD_VAL - 1;
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#endif
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	do {
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		timenow = readl(&timer_base->counter);
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		if (timenow >= timeend) {
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			/* normal case */
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			timediff = timenow - timeend;
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		} else {
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			if ((TIMER_LOAD_VAL - timeend + timenow) <=
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								countticks) {
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				/* overflow */
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				timediff = TIMER_LOAD_VAL - timeend + timenow;
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			} else {
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				/* missed the exact match */
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				break;
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			}
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		}
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	} while (timediff > 0);
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}
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/* Timer without interrupts */
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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 (read timebase as long long).
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 * On ARM it just returns the timer value.
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 */
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unsigned long long get_ticks(void)
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{
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	return get_timer(0);
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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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	return CONFIG_SYS_HZ;
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}
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