[PATCH 04/07] Add TCC8xxx system timer

Hans J. Koch
2010-03-22T19:26:23Z

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" <hjk@linutronix.de>
---
arch/arm/Kconfig | 1 +
arch/arm/mach-tcc8k/Makefile | 2 +-
arch/arm/mach-tcc8k/time.c | 150 ++++++++++++++++++++++++++++++++
arch/arm/plat-tcc/include/mach/timex.h | 5 +
4 files changed, 157 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 8b9429c..7c6e731 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -728,6 +728,7 @@ 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..db0a6da
--- /dev/null
+++ b/arch/arm/mach-tcc8k/time.c
@@ -0,0 +1,150 @@
+/*
+ * TCC8000 system timer setup
+ *
+ * (C) 2009 Hans J. Koch <hjk@linutronix.de>
+ *
+ * Licensed under the terms of the GPL version 2.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/irq.h>
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+
+#include <asm/io.h>
+#include <asm/mach/time.h>
+
+#include <mach/tcc8k-regs.h>
+#include <mach/irqs.h>
+
+static void __iomem *timer_base;
+static struct clock_event_device clockevent_tcc;
+static enum clock_event_mode clockevent_mode = CLOCK_EVT_MODE_UNUSED;
+
+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;
+
+ clockevent_mode = mode;
+
+ 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 = &clockevent_tcc;
+
+ /* Acknowledge TC32 interrupt by reading TC32IRQ */
+ __raw_readl(timer_base + TC32IRQ_OFFS);
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction tcc8k_timer_irq = {
+ .name = "TC32_timer",
+ .flags = IRQF_DISABLED | IRQF_TIMER,
+ .handler = tcc8k_timer_interrupt,
+};
+
+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 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