diff options
author | Hans J. Koch <hjk@linutronix.de> | 2010-09-17 18:17:42 +0200 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2010-09-17 21:55:08 +0200 |
commit | 3de7b517dfacf1deb0690dbac28f917643e49975 (patch) | |
tree | 77548d323cef82e380f354f98132dc779aee0919 /arch/arm/mach-tcc8k/time.c | |
parent | e9268ef2252c2dfc7e2d0c435826768bb0e549ea (diff) |
ARM: Add TCC8xxx system timer
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>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/arm/mach-tcc8k/time.c')
-rw-r--r-- | arch/arm/mach-tcc8k/time.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/arch/arm/mach-tcc8k/time.c b/arch/arm/mach-tcc8k/time.c new file mode 100644 index 00000000000..78d06008841 --- /dev/null +++ b/arch/arm/mach-tcc8k/time.c @@ -0,0 +1,149 @@ +/* + * TCC8000 system timer setup + * + * (C) 2009 Hans J. Koch <hjk@linutronix.de> + * + * 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> + +#include "common.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); +} |