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m68knommu: Add Coldfire DMA Timer support

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This one could be used as a hrtimer.

Signed-off-by: Benedikt Spranger <b.spranger@linutronix.de>
Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
This commit is contained in:
Sebastian Siewior 2008-05-09 16:18:33 +02:00 committed by Greg Ungerer
parent ab88e474c8
commit 5732b38ddb
2 changed files with 69 additions and 1 deletions
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2
arch/m68knommu/platform/coldfire/Makefile
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@ -18,7 +18,7 @@ obj-$(CONFIG_COLDFIRE) += dma.o entry.o vectors.o
obj-$(CONFIG_M5206) += timers.o
obj-$(CONFIG_M5206e) += timers.o
obj-$(CONFIG_M520x) += pit.o
obj-$(CONFIG_M523x) += pit.o
obj-$(CONFIG_M523x) += pit.o dma_timer.o
obj-$(CONFIG_M5249) += timers.o
obj-$(CONFIG_M527x) += pit.o
obj-$(CONFIG_M5272) += timers.o

68
arch/m68knommu/platform/coldfire/dma_timer.c Normal file
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@ -0,0 +1,68 @@
/*
* dma_timer.c -- Freescale ColdFire DMA Timer.
*
* Copyright (C) 2007, Benedikt Spranger <b.spranger@linutronix.de>
* Copyright (C) 2008. Sebastian Siewior, Linutronix
*
*/
#include <linux/clocksource.h>
#include <linux/io.h>
#include <asm/machdep.h>
#include <asm/coldfire.h>
#include <asm/mcfpit.h>
#include <asm/mcfsim.h>
#define DMA_TIMER_0 (0x00)
#define DMA_TIMER_1 (0x40)
#define DMA_TIMER_2 (0x80)
#define DMA_TIMER_3 (0xc0)
#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)
#define DMA_FREQ ((MCF_CLK / 2) / 16)
/* 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)
static cycle_t cf_dt_get_cycles(void)
{
return __raw_readl(DTCN0);
}
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,
};
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);
}
arch_initcall(init_cf_dt_clocksource);