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authorSebastian Siewior <bigeasy@linutronix.de>2008-05-09 16:18:33 +0200
committerGreg Ungerer <gerg@uclinux.org>2008-07-23 15:11:27 +1000
commit5732b38ddb770b98110ea218232fc072e5626b87 (patch)
tree626eb241ce1b9ff55941e7671660e5219a206420 /arch/m68knommu
parentab88e474c8ffa300660f03a8e6b08ea660956bef (diff)
m68knommu: Add Coldfire DMA Timer support
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>
Diffstat (limited to 'arch/m68knommu')
-rw-r--r--arch/m68knommu/platform/coldfire/Makefile2
-rw-r--r--arch/m68knommu/platform/coldfire/dma_timer.c68
2 files changed, 69 insertions, 1 deletions
diff --git a/arch/m68knommu/platform/coldfire/Makefile b/arch/m68knommu/platform/coldfire/Makefile
index 40cf20be1b90..4f416a91a829 100644
--- a/arch/m68knommu/platform/coldfire/Makefile
+++ b/arch/m68knommu/platform/coldfire/Makefile
@@ -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
diff --git a/arch/m68knommu/platform/coldfire/dma_timer.c b/arch/m68knommu/platform/coldfire/dma_timer.c
new file mode 100644
index 000000000000..b623c993219e
--- /dev/null
+++ b/arch/m68knommu/platform/coldfire/dma_timer.c
@@ -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);