[uClinux-dev] [RFC] Add Coldfire DMA Timer support v3 (contains brown paper bag fix)

Sebastian Siewior bigeasy at linutronix.de
Tue Apr 8 14:55:00 EDT 2008


The subject says it all.

Signed-off-by: Benedikt Spranger <b.spranger at linutronix.de>
Signed-off-by: Sebastian Siewior <bigeasy at linutronix.de>
--- 
Mixed up the frequency. This patch has been tested :)

--- a/arch/m68knommu/platform/coldfire/Makefile
+++ b/arch/m68knommu/platform/coldfire/Makefile
@@ -20,7 +20,7 @@ obj-$(CONFIG_COLDFIRE)	+= dma.o entry.o 
 obj-$(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
--- /dev/null
+++ b/arch/m68knommu/platform/coldfire/dma_timer.c
@@ -0,0 +1,59 @@
+/*
+ * dma_timer.c -- Freescale ColdFire DMA Timer.
+ *
+ * Copyright (C) 2007, Benedikt Spranger <b.spranger at linutronix.de>
+ */
+
+#include <linux/clocksource.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <linux/timer.h>
+
+#include <asm/machdep.h>
+#include <asm/coldfire.h>
+#include <asm/mcfpit.h>
+#include <asm/mcfsim.h>
+
+#define DTMR0	MCF_IPSBAR + 0x400
+#define DTXMR0	MCF_IPSBAR + 0x402
+#define DTER0	MCF_IPSBAR + 0x403
+#define DTRR0	MCF_IPSBAR + 0x404
+#define DTCR0	MCF_IPSBAR + 0x408
+#define DTCN0	MCF_IPSBAR + 0x40c
+
+#define DMA_FREQ    ((MCF_CLK / 2) / 16)
+
+/*
+ *	By default use DMA Timer 0 as the system time source.
+ */
+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)
+{
+	__raw_writew(0x000d, DTMR0);
+	__raw_writeb(0x00, DTXMR0);
+	__raw_writeb(0x00, DTER0);
+	__raw_writel(0xffffffff, DTRR0);
+
+	clocksource_cf_dt.mult = clocksource_hz2mult(DMA_FREQ,
+						     clocksource_cf_dt.shift);
+	return clocksource_register(&clocksource_cf_dt);
+}
+
+arch_initcall(init_cf_dt_clocksource);



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