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https://github.com/AsahiLinux/u-boot
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38b343dd05
Add timer driver. Signed-off-by: Michal Simek <monstr@monstr.eu> CC: Joe Hershberger <joe.hershberger@gmail.com> CC: Marek Vasut <marex@denx.de> Acked-by: Marek Vasut <marex@denx.de>
150 lines
3.9 KiB
C
150 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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* 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 <div64.h>
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#include <asm/io.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 *) CONFIG_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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#define TIMER_TICK_HZ (CONFIG_CPU_FREQ_HZ / 2 / TIMER_PRESCALE)
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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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/* Load the timer counter register */
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writel(0xFFFFFFFF, &timer_base->counter);
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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->lastinc = readl(&timer_base->counter) /
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(TIMER_TICK_HZ / CONFIG_SYS_HZ);
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gd->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) / (TIMER_TICK_HZ / CONFIG_SYS_HZ);
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if (gd->lastinc >= now) {
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/* Normal mode */
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gd->tbl += gd->lastinc - now;
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} else {
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/* We have an overflow ... */
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gd->tbl += gd->lastinc + TIMER_LOAD_VAL - now;
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}
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gd->lastinc = now;
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return gd->tbl;
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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 / (1000000 / CONFIG_SYS_HZ);
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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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}
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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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