*
* Copyright (C) 2000-2001 Deep Blue Solutions
* Copyright (C) 2002 Shane Nay (shane@minirl.com)
+ * Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
#include <linux/irq.h>
#include <linux/time.h>
#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/clk.h>
#include <asm/hardware.h>
#include <asm/io.h>
/* Use timer 1 as system timer */
#define TIMER_BASE IMX_TIM1_BASE
-static unsigned long evt_diff;
+static struct clock_event_device clockevent_imx;
+static enum clock_event_mode clockevent_mode = CLOCK_EVT_MODE_UNUSED;
/*
* IRQ handler for the timer
static irqreturn_t
imx_timer_interrupt(int irq, void *dev_id)
{
+ struct clock_event_device *evt = &clockevent_imx;
uint32_t tstat;
+ irqreturn_t ret = IRQ_NONE;
/* clear the interrupt */
tstat = IMX_TSTAT(TIMER_BASE);
IMX_TSTAT(TIMER_BASE) = 0;
if (tstat & TSTAT_COMP) {
- do {
-
- write_seqlock(&xtime_lock);
- timer_tick();
- write_sequnlock(&xtime_lock);
- IMX_TCMP(TIMER_BASE) += evt_diff;
-
- } while (unlikely((int32_t)(IMX_TCMP(TIMER_BASE)
- - IMX_TCN(TIMER_BASE)) < 0));
+ evt->event_handler(evt);
+ ret = IRQ_HANDLED;
}
- return IRQ_HANDLED;
+ return ret;
}
static struct irqaction imx_timer_irq = {
*/
IMX_TCTL(TIMER_BASE) = 0;
IMX_TPRER(TIMER_BASE) = 0;
- IMX_TCMP(TIMER_BASE) = LATCH - 1;
- IMX_TCTL(TIMER_BASE) = TCTL_FRR | TCTL_CLK_PCLK1 | TCTL_IRQEN | TCTL_TEN;
- evt_diff = LATCH;
+ IMX_TCTL(TIMER_BASE) = TCTL_FRR | TCTL_CLK_PCLK1 | TCTL_TEN;
}
cycle_t imx_get_cycles(void)
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
-static int __init imx_clocksource_init(void)
+static int __init imx_clocksource_init(unsigned long rate)
{
clocksource_imx.mult =
- clocksource_hz2mult(imx_get_perclk1(), clocksource_imx.shift);
+ clocksource_hz2mult(rate, clocksource_imx.shift);
clocksource_register(&clocksource_imx);
return 0;
}
+static int imx_set_next_event(unsigned long evt,
+ struct clock_event_device *unused)
+{
+ unsigned long tcmp;
+
+ tcmp = IMX_TCN(TIMER_BASE) + evt;
+ IMX_TCMP(TIMER_BASE) = tcmp;
+
+ return (int32_t)(tcmp - IMX_TCN(TIMER_BASE)) < 0 ? -ETIME : 0;
+}
+
+#ifdef DEBUG
+static const char *clock_event_mode_label[]={
+ [CLOCK_EVT_MODE_PERIODIC] = "CLOCK_EVT_MODE_PERIODIC",
+ [CLOCK_EVT_MODE_ONESHOT] = "CLOCK_EVT_MODE_ONESHOT",
+ [CLOCK_EVT_MODE_SHUTDOWN] = "CLOCK_EVT_MODE_SHUTDOWN",
+ [CLOCK_EVT_MODE_UNUSED] = "CLOCK_EVT_MODE_UNUSED"
+};
+#endif /*DEBUG*/
+
+static void imx_set_mode(enum clock_event_mode mode, struct clock_event_device *evt)
+{
+ unsigned long flags;
+
+ /*
+ * The timer interrupt generation is disabled at least
+ * for enough time to call imx_set_next_event()
+ */
+ local_irq_save(flags);
+ /* Disable interrupt in GPT module */
+ IMX_TCTL(TIMER_BASE) &= ~TCTL_IRQEN;
+ if (mode != clockevent_mode) {
+ /* Set event time into far-far future */
+ IMX_TCMP(TIMER_BASE) = IMX_TCN(TIMER_BASE) - 3;
+ /* Clear pending interrupt */
+ IMX_TSTAT(TIMER_BASE) &= ~TSTAT_COMP;
+ }
+
+#ifdef DEBUG
+ printk(KERN_INFO "imx_set_mode: changing mode from %s to %s\n",
+ clock_event_mode_label[clockevent_mode], clock_event_mode_label[mode]);
+#endif /*DEBUG*/
+
+ /* Remember timer mode */
+ clockevent_mode = mode;
+ local_irq_restore(flags);
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ printk(KERN_ERR "imx_set_mode: Periodic mode is not supported for i.MX\n");
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ /*
+ * Do not put overhead of interrupt enable/disable into
+ * imx_set_next_event(), the core has about 4 minutes
+ * to call imx_set_next_event() or shutdown clock after
+ * mode switching
+ */
+ local_irq_save(flags);
+ IMX_TCTL(TIMER_BASE) |= TCTL_IRQEN;
+ local_irq_restore(flags);
+ break;
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_RESUME:
+ /* Left event sources disabled, no more interrupts appears */
+ break;
+ }
+}
+
+static struct clock_event_device clockevent_imx = {
+ .name = "imx_timer1",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .shift = 32,
+ .set_mode = imx_set_mode,
+ .set_next_event = imx_set_next_event,
+ .rating = 200,
+};
+
+static int __init imx_clockevent_init(unsigned long rate)
+{
+ clockevent_imx.mult = div_sc(rate, NSEC_PER_SEC,
+ clockevent_imx.shift);
+ clockevent_imx.max_delta_ns =
+ clockevent_delta2ns(0xfffffffe, &clockevent_imx);
+ clockevent_imx.min_delta_ns =
+ clockevent_delta2ns(0xf, &clockevent_imx);
+
+ clockevent_imx.cpumask = cpumask_of_cpu(0);
+
+ clockevents_register_device(&clockevent_imx);
+
+ return 0;
+}
+
+extern int imx_clocks_init(void);
+
static void __init imx_timer_init(void)
{
+ struct clk *clk;
+ unsigned long rate;
+
+ imx_clocks_init();
+
+ clk = clk_get(NULL, "perclk1");
+ clk_enable(clk);
+ rate = clk_get_rate(clk);
+
imx_timer_hardware_init();
- imx_clocksource_init();
+ imx_clocksource_init(rate);
+
+ imx_clockevent_init(rate);
/*
* Make irqs happen for the system timer
git.openpandora.org / pandora-kernel.git / blobdiff