75b37696fb
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@20585 a1c6a512-1295-4272-9138-f99709370657
106 lines
2.7 KiB
C
106 lines
2.7 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2008 by Rob Purchase
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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
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "config.h"
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#include "cpu.h"
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#include "system.h"
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#include "timer.h"
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#include "logf.h"
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static const int prescale_shifts[] = {1, 2, 3, 4, 5, 10, 12};
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bool __timer_set(long cycles, bool start)
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{
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bool found = false;
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int prescale_option = 0;
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int actual_cycles = 0;
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/* Use the first prescale that fits Timer4's 20-bit counter */
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while (!found && prescale_option < 7)
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{
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actual_cycles = cycles >> prescale_shifts[prescale_option];
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if (actual_cycles < 0x100000)
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found = true;
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else
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prescale_option++;
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}
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if (!found)
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return false;
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/* Stop the timer and set new prescale & ref count */
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TCFG(4) &= ~TCFG_EN;
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TCFG(4) = prescale_option << TCFG_SEL;
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TREF(4) = actual_cycles;
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if (start && pfn_unregister != NULL)
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{
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pfn_unregister();
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pfn_unregister = NULL;
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}
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return true;
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}
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bool __timer_register(void)
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{
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int oldstatus = disable_interrupt_save(IRQ_STATUS);
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TCFG(4) |= TCFG_CLEAR | TCFG_IEN | TCFG_EN;
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restore_interrupt(oldstatus);
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return true;
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}
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void __timer_unregister(void)
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{
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int oldstatus = disable_interrupt_save(IRQ_STATUS);
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TCFG(4) &= ~TCFG_EN;
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restore_interrupt(oldstatus);
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}
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/* Timer interrupt processing - all timers (inc. tick) have a single IRQ */
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void TIMER0(void)
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{
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if (TIREQ & TIREQ_TF0) /* Timer0 reached ref value */
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{
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/* Run through the list of tick tasks */
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call_tick_tasks();
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/* reset Timer 0 IRQ & ref flags */
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TIREQ = TIREQ_TI0 | TIREQ_TF0;
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}
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if (TIREQ & TIREQ_TF4) /* Timer4 reached ref value */
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{
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/* dispatch user timer */
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if (pfn_timer != NULL)
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pfn_timer();
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TIREQ = TIREQ_TI4 | TIREQ_TF4;
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}
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}
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