100 lines
2.6 KiB
C
100 lines
2.6 KiB
C
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/*
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* (C) Copyright 2000, 2001
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* Wolfgang Denk, DENX Software Engineering, wd@denx.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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/* ------------------------------------------------------------------------- */
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/*
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* This function is intended for SHORT delays only.
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* It will overflow at around 10 seconds @ 400MHz,
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* or 20 seconds @ 200MHz.
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*/
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unsigned long usec2ticks(unsigned long usec)
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{
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ulong ticks;
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if (usec < 1000) {
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ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
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} else {
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ticks = ((usec / 10) * (get_tbclk() / 100000));
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}
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return (ticks);
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}
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/* ------------------------------------------------------------------------- */
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/*
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* We implement the delay by converting the delay (the number of
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* microseconds to wait) into a number of time base ticks; then we
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* watch the time base until it has incremented by that amount.
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*/
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void udelay(unsigned long usec)
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{
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ulong ticks = usec2ticks (usec);
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wait_ticks (ticks);
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}
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/* ------------------------------------------------------------------------- */
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unsigned long ticks2usec(unsigned long ticks)
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{
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ulong tbclk = get_tbclk();
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/* usec = ticks * 1000000 / tbclk
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* Multiplication would overflow at ~4.2e3 ticks,
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* so we break it up into
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* usec = ( ( ticks * 1000) / tbclk ) * 1000;
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*/
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ticks *= 1000L;
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ticks /= tbclk;
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ticks *= 1000L;
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return ((ulong)ticks);
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}
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/* ------------------------------------------------------------------------- */
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int init_timebase (void)
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{
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#if defined(CONFIG_5xx) || defined(CONFIG_8xx)
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volatile immap_t *immap = (immap_t *) CFG_IMMR;
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/* unlock */
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immap->im_sitk.sitk_tbk = KAPWR_KEY;
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#endif
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/* reset */
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asm ("li 3,0 ; mttbu 3 ; mttbl 3 ;");
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#if defined(CONFIG_5xx) || defined(CONFIG_8xx)
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/* enable */
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immap->im_sit.sit_tbscr |= TBSCR_TBE;
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#endif
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return (0);
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}
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/* ------------------------------------------------------------------------- */
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