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yaml --- r: 105602 b: refs/heads/master c: 5732b38 h: refs/heads/master v: v3
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Sebastian Siewior
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Greg Ungerer
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Jul 23, 2008
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refs/heads/master: ab88e474c8ffa300660f03a8e6b08ea660956bef | ||
refs/heads/master: 5732b38ddb770b98110ea218232fc072e5626b87 |
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/* | ||
* dma_timer.c -- Freescale ColdFire DMA Timer. | ||
* | ||
* Copyright (C) 2007, Benedikt Spranger <b.spranger@linutronix.de> | ||
* Copyright (C) 2008. Sebastian Siewior, Linutronix | ||
* | ||
*/ | ||
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#include <linux/clocksource.h> | ||
#include <linux/io.h> | ||
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#include <asm/machdep.h> | ||
#include <asm/coldfire.h> | ||
#include <asm/mcfpit.h> | ||
#include <asm/mcfsim.h> | ||
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#define DMA_TIMER_0 (0x00) | ||
#define DMA_TIMER_1 (0x40) | ||
#define DMA_TIMER_2 (0x80) | ||
#define DMA_TIMER_3 (0xc0) | ||
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#define DTMR0 (MCF_IPSBAR + DMA_TIMER_0 + 0x400) | ||
#define DTXMR0 (MCF_IPSBAR + DMA_TIMER_0 + 0x402) | ||
#define DTER0 (MCF_IPSBAR + DMA_TIMER_0 + 0x403) | ||
#define DTRR0 (MCF_IPSBAR + DMA_TIMER_0 + 0x404) | ||
#define DTCR0 (MCF_IPSBAR + DMA_TIMER_0 + 0x408) | ||
#define DTCN0 (MCF_IPSBAR + DMA_TIMER_0 + 0x40c) | ||
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#define DMA_FREQ ((MCF_CLK / 2) / 16) | ||
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/* DTMR */ | ||
#define DMA_DTMR_RESTART (1 << 3) | ||
#define DMA_DTMR_CLK_DIV_1 (1 << 1) | ||
#define DMA_DTMR_CLK_DIV_16 (2 << 1) | ||
#define DMA_DTMR_ENABLE (1 << 0) | ||
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static cycle_t cf_dt_get_cycles(void) | ||
{ | ||
return __raw_readl(DTCN0); | ||
} | ||
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static struct clocksource clocksource_cf_dt = { | ||
.name = "coldfire_dma_timer", | ||
.rating = 200, | ||
.read = cf_dt_get_cycles, | ||
.mask = CLOCKSOURCE_MASK(32), | ||
.shift = 20, | ||
.flags = CLOCK_SOURCE_IS_CONTINUOUS, | ||
}; | ||
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static int __init init_cf_dt_clocksource(void) | ||
{ | ||
/* | ||
* We setup DMA timer 0 in free run mode. This incrementing counter is | ||
* used as a highly precious clock source. With MCF_CLOCK = 150 MHz we | ||
* get a ~213 ns resolution and the 32bit register will overflow almost | ||
* every 15 minutes. | ||
*/ | ||
__raw_writeb(0x00, DTXMR0); | ||
__raw_writeb(0x00, DTER0); | ||
__raw_writel(0x00000000, DTRR0); | ||
__raw_writew(DMA_DTMR_CLK_DIV_16 | DMA_DTMR_ENABLE, DTMR0); | ||
clocksource_cf_dt.mult = clocksource_hz2mult(DMA_FREQ, | ||
clocksource_cf_dt.shift); | ||
return clocksource_register(&clocksource_cf_dt); | ||
} | ||
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arch_initcall(init_cf_dt_clocksource); |