56 lines
1.5 KiB
C
56 lines
1.5 KiB
C
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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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#include <config.h>
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#include <common.h>
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#include <init.h>
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#include <clock.h>
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#include <io.h>
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#include <mach/s3c-iomap.h>
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#include <mach/s3c-generic.h>
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static uint64_t s3c24xx_clocksource_read(void)
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{
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/* note: its a down counter */
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return 0xFFFF - readw(TCNTO4);
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}
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static struct clocksource cs = {
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.read = s3c24xx_clocksource_read,
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.mask = CLOCKSOURCE_MASK(16),
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.shift = 10,
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};
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static int clocksource_init(void)
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{
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uint32_t p_clk = s3c_get_pclk();
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writel(0x00000000, TCON); /* stop all timers */
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writel(0x00ffffff, TCFG0); /* PCLK / (255 + 1) for timer 4 */
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writel(0x00030000, TCFG1); /* /16 */
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writew(0xffff, TCNTB4); /* reload value is TOP */
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writel(0x00600000, TCON); /* force a first reload */
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writel(0x00400000, TCON);
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writel(0x00500000, TCON); /* enable timer 4 with auto reload */
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cs.mult = clocksource_hz2mult(p_clk / ((255 + 1) * 16), cs.shift);
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init_clock(&cs);
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return 0;
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}
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core_initcall(clocksource_init);
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