Subject: [PATCH 4/7 v6] Add TCC8xxx system timer

From: [email-masked] (Hans J. Koch)
Date: Wed, 26 May 2010 19:50:35 +0200

Add the system timer using clockevents with the internal TC32 timer.
This also adds a clocksource using the same timer.

Signed-off-by: "Hans J. Koch" <[email-masked]>
---
 arch/arm/Kconfig                       |    1 +
 arch/arm/mach-tcc8k/Makefile           |    2 +-
 arch/arm/mach-tcc8k/time.c             |  147 ++++++++++++++++++++++++++++++++
 arch/arm/plat-tcc/include/mach/timex.h |    5 +
 4 files changed, 154 insertions(+), 1 deletions(-)
 create mode 100644 arch/arm/mach-tcc8k/time.c
 create mode 100644 arch/arm/plat-tcc/include/mach/timex.h

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index dd7001d..aa78cee 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -729,6 +729,7 @@ config ARCH_TCC_926
 	select CPU_ARM926T
 	select HAVE_CLK
 	select COMMON_CLKDEV
+	select GENERIC_TIME
 	select GENERIC_CLOCKEVENTS
 	help
 	  Support for Telechips TCC ARM926-based systems.
diff --git a/arch/arm/mach-tcc8k/Makefile b/arch/arm/mach-tcc8k/Makefile
index 24356e9..5673868 100644
--- a/arch/arm/mach-tcc8k/Makefile
+++ b/arch/arm/mach-tcc8k/Makefile
@@ -3,5 +3,5 @@
 #
 
 # Common support
-obj-y += clock.o irq.o
+obj-y += clock.o irq.o time.o
 
diff --git a/arch/arm/mach-tcc8k/time.c b/arch/arm/mach-tcc8k/time.c
new file mode 100644
index 0000000..2dd876b
--- /dev/null
+++ b/arch/arm/mach-tcc8k/time.c
@@ -0,0 +1,147 @@
+/*
+ * TCC8000 system timer setup
+ *
+ * (C) 2009 Hans J. Koch <[email-masked]>
+ *
+ * Licensed under the terms of the GPL version 2.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+
+#include <asm/mach/time.h>
+
+#include <mach/tcc8k-regs.h>
+#include <mach/irqs.h>
+
+static void __iomem *timer_base;
+
+static cycle_t tcc_get_cycles(struct clocksource *cs)
+{
+	return __raw_readl(timer_base + TC32MCNT_OFFS);
+}
+
+static struct clocksource clocksource_tcc = {
+	.name		= "tcc_tc32",
+	.rating		= 200,
+	.read		= tcc_get_cycles,
+	.mask		= CLOCKSOURCE_MASK(32),
+	.shift		= 28,
+	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static int tcc_set_next_event(unsigned long evt,
+			      struct clock_event_device *unused)
+{
+	unsigned long reg = __raw_readl(timer_base + TC32MCNT_OFFS);
+
+	__raw_writel(reg + evt, timer_base + TC32CMP0_OFFS);
+	return 0;
+}
+
+static void tcc_set_mode(enum clock_event_mode mode,
+				struct clock_event_device *evt)
+{
+	unsigned long tc32irq;
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_ONESHOT:
+		tc32irq = __raw_readl(timer_base + TC32IRQ_OFFS);
+		tc32irq |= TC32IRQ_IRQEN0;
+		__raw_writel(tc32irq, timer_base + TC32IRQ_OFFS);
+		break;
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	case CLOCK_EVT_MODE_UNUSED:
+		tc32irq = __raw_readl(timer_base + TC32IRQ_OFFS);
+		tc32irq &= ~TC32IRQ_IRQEN0;
+		__raw_writel(tc32irq, timer_base + TC32IRQ_OFFS);
+		break;
+	case CLOCK_EVT_MODE_PERIODIC:
+	case CLOCK_EVT_MODE_RESUME:
+		break;
+	}
+}
+
+static irqreturn_t tcc8k_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = dev_id;
+
+	/* Acknowledge TC32 interrupt by reading TC32IRQ */
+	__raw_readl(timer_base + TC32IRQ_OFFS);
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+static struct clock_event_device clockevent_tcc = {
+	.name		= "tcc_timer1",
+	.features	= CLOCK_EVT_FEAT_ONESHOT,
+	.shift		= 32,
+	.set_mode	= tcc_set_mode,
+	.set_next_event	= tcc_set_next_event,
+	.rating		= 200,
+};
+
+static struct irqaction tcc8k_timer_irq = {
+	.name		= "TC32_timer",
+	.flags		= IRQF_DISABLED | IRQF_TIMER,
+	.handler	= tcc8k_timer_interrupt,
+	.dev_id		= &clockevent_tcc,
+};
+
+static int __init tcc_clockevent_init(struct clk *clock)
+{
+	unsigned int c = clk_get_rate(clock);
+
+	clocksource_tcc.mult = clocksource_hz2mult(c,
+					clocksource_tcc.shift);
+	clocksource_register(&clocksource_tcc);
+
+	clockevent_tcc.mult = div_sc(c, NSEC_PER_SEC,
+					clockevent_tcc.shift);
+	clockevent_tcc.max_delta_ns =
+			clockevent_delta2ns(0xfffffffe, &clockevent_tcc);
+	clockevent_tcc.min_delta_ns =
+			clockevent_delta2ns(0xff, &clockevent_tcc);
+
+	clockevent_tcc.cpumask = cpumask_of(0);
+
+	clockevents_register_device(&clockevent_tcc);
+
+	return 0;
+}
+
+void __init tcc8k_timer_init(struct clk *clock, void __iomem *base, int irq)
+{
+	u32 reg;
+
+	timer_base = base;
+	tcc8k_timer_irq.irq = irq;
+
+	/* Enable clocks */
+	clk_enable(clock);
+
+	/* Initialize 32-bit timer */
+	reg = __raw_readl(timer_base + TC32EN_OFFS);
+	reg &= ~TC32EN_ENABLE; /* Disable timer */
+	__raw_writel(reg, timer_base + TC32EN_OFFS);
+	/* Free running timer, counting from 0 to 0xffffffff */
+	__raw_writel(0, timer_base + TC32EN_OFFS);
+	__raw_writel(0, timer_base + TC32LDV_OFFS);
+	reg = __raw_readl(timer_base + TC32IRQ_OFFS);
+	reg |= TC32IRQ_IRQEN0; /* irq at match with CMP0 */
+	__raw_writel(reg, timer_base + TC32IRQ_OFFS);
+
+	__raw_writel(TC32EN_ENABLE, timer_base + TC32EN_OFFS);
+
+	tcc_clockevent_init(clock);
+	setup_irq(irq, &tcc8k_timer_irq);
+}
diff --git a/arch/arm/plat-tcc/include/mach/timex.h b/arch/arm/plat-tcc/include/mach/timex.h
new file mode 100644
index 0000000..057acbe
--- /dev/null
+++ b/arch/arm/plat-tcc/include/mach/timex.h
@@ -0,0 +1,5 @@
+/*
+ * A definition needed by arch core code.
+ *
+ */
+#define CLOCK_TICK_RATE		(HZ * 100000UL)
-- 
1.6.3.3