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;
}
/*
* Set up timer hardware into expected mode and state.
*/
static void __init imx_timer_hardware_init(void)
{
/*
* Initialise to a known state (all timers off, and timing reset)
*/
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;
}
/*
* IRQ handler for the timer
*/
static irqreturn_t
imx_timer_interrupt(int irq, void *dev_id)
{
uint32_t tstat;
/* 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));
}
return IRQ_HANDLED;
}
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;
}
}
/*
* Set up timer interrupt, and return the current time in seconds.
*/
static void __init imx_timer_init(void)
{
/*
* Initialise to a known state (all timers off, and timing reset)
*/
IMX_TCTL(TIMER_BASE) = 0;
IMX_TPRER(TIMER_BASE) = 0;
IMX_TCMP(TIMER_BASE) = LATCH - 1;
IMX_TCTL(TIMER_BASE) = TCTL_CLK_32 | TCTL_IRQEN | TCTL_TEN;
/*
* Make irqs happen for the system timer
*/
setup_irq(TIM1_INT, &imx_timer_irq);
}