static int
clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev)
{
u32 alm;
int status = 0;
BUG_ON(delta < 2);
/* The alarm IRQ uses absolute time (now+delta), not the relative
* time (delta) in our calling convention. Like all clockevents
* using such "match" hardware, we have a race to defend against.
*
* Our defense here is to have set up the clockevent device so the
* delta is at least two. That way we never end up writing RTAR
* with the value then held in CRTR ... which would mean the match
* wouldn't trigger until 32 seconds later, after CRTR wraps.
*/
alm = read_CRTR();
/* Cancel any pending alarm; flush any pending IRQ */
at91_st_write(AT91_ST_RTAR, alm);
at91_st_read(AT91_ST_SR);
/* Schedule alarm by writing RTAR. */
alm += delta;
at91_st_write(AT91_ST_RTAR, alm);
return status;
}
static void
clkevt32k_mode(enum clock_event_mode mode, struct clock_event_device *dev)
{
at91_st_write(AT91_ST_IDR, AT91_ST_PITS | AT91_ST_ALMS);
at91_st_read(AT91_ST_SR);
last_crtr = read_CRTR();
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
irqmask = AT91_ST_PITS;
at91_st_write(AT91_ST_PIMR, RM9200_TIMER_LATCH);
break;
case CLOCK_EVT_MODE_ONESHOT:
irqmask = AT91_ST_ALMS;
at91_st_write(AT91_ST_RTAR, last_crtr);
break;
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_RESUME:
irqmask = 0;
break;
}
at91_st_write(AT91_ST_IER, irqmask);
}
static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id)
{
u32 sr = at91_st_read(AT91_ST_SR) & irqmask;
WARN_ON_ONCE(!irqs_disabled());
if (sr & AT91_ST_ALMS) {
clkevt.event_handler(&clkevt);
return IRQ_HANDLED;
}
if (sr & AT91_ST_PITS) {
u32 crtr = read_CRTR();
while (((crtr - last_crtr) & AT91_ST_CRTV) >= RM9200_TIMER_LATCH) {
last_crtr += RM9200_TIMER_LATCH;
clkevt.event_handler(&clkevt);
}
return IRQ_HANDLED;
}
return IRQ_NONE;
}
/*
* IRQ handler for the timer.
*/
static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id)
{
u32 sr = at91_st_read(AT91_ST_SR) & irqmask;
/*
* irqs should be disabled here, but as the irq is shared they are only
* guaranteed to be off if the timer irq is registered first.
*/
WARN_ON_ONCE(!irqs_disabled());
/* simulate "oneshot" timer with alarm */
if (sr & AT91_ST_ALMS) {
clkevt.event_handler(&clkevt);
return IRQ_HANDLED;
}
/* periodic mode should handle delayed ticks */
if (sr & AT91_ST_PITS) {
u32 crtr = read_CRTR();
while (((crtr - last_crtr) & AT91_ST_CRTV) >= RM9200_TIMER_LATCH) {
last_crtr += RM9200_TIMER_LATCH;
clkevt.event_handler(&clkevt);
}
return IRQ_HANDLED;
}
/* this irq is shared ... */
return IRQ_NONE;
}
static void
clkevt32k_mode(enum clock_event_mode mode, struct clock_event_device *dev)
{
/* Disable and flush pending timer interrupts */
at91_st_write(AT91_ST_IDR, AT91_ST_PITS | AT91_ST_ALMS);
at91_st_read(AT91_ST_SR);
last_crtr = read_CRTR();
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
/* PIT for periodic irqs; fixed rate of 1/HZ */
irqmask = AT91_ST_PITS;
at91_st_write(AT91_ST_PIMR, RM9200_TIMER_LATCH);
break;
case CLOCK_EVT_MODE_ONESHOT:
/* ALM for oneshot irqs, set by next_event()
* before 32 seconds have passed
*/
irqmask = AT91_ST_ALMS;
at91_st_write(AT91_ST_RTAR, last_crtr);
break;
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_RESUME:
irqmask = 0;
break;
}
at91_st_write(AT91_ST_IER, irqmask);
}
static void
clkevt32k_mode(enum clock_event_mode mode, struct clock_event_device *dev)
{
unsigned int val;
/* Disable and flush pending timer interrupts */
regmap_write(regmap_st, AT91_ST_IDR, AT91_ST_PITS | AT91_ST_ALMS);
regmap_read(regmap_st, AT91_ST_SR, &val);
last_crtr = read_CRTR();
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
/* PIT for periodic irqs; fixed rate of 1/HZ */
irqmask = AT91_ST_PITS;
regmap_write(regmap_st, AT91_ST_PIMR, RM9200_TIMER_LATCH);
break;
case CLOCK_EVT_MODE_ONESHOT:
/* ALM for oneshot irqs, set by next_event()
* before 32 seconds have passed
*/
irqmask = AT91_ST_ALMS;
regmap_write(regmap_st, AT91_ST_RTAR, last_crtr);
break;
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
remove_irq(NR_IRQS_LEGACY + AT91_ID_SYS, &at91rm9200_timer_irq);
case CLOCK_EVT_MODE_RESUME:
irqmask = 0;
break;
}
regmap_write(regmap_st, AT91_ST_IER, irqmask);
}
/*
* Returns number of microseconds since last timer interrupt. Note that interrupts
* will have been disabled by do_gettimeofday()
* 'LATCH' is hwclock ticks (see CLOCK_TICK_RATE in timex.h) per jiffy.
* 'tick' is usecs per jiffy (linux/timex.h).
*/
static unsigned long at91rm9200_gettimeoffset(void)
{
unsigned long elapsed;
elapsed = (read_CRTR() - last_crtr) & AT91_ST_ALMV;
return (unsigned long)(elapsed * (tick_nsec / 1000)) / LATCH;
}
static void clkdev32k_disable_and_flush_irq(void)
{
unsigned int val;
/* Disable and flush pending timer interrupts */
regmap_write(regmap_st, AT91_ST_IDR, AT91_ST_PITS | AT91_ST_ALMS);
regmap_read(regmap_st, AT91_ST_SR, &val);
last_crtr = read_CRTR();
}
/*
* IRQ handler for the timer.
*/
static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
if (at91_sys_read(AT91_ST_SR) & AT91_ST_PITS) { /* This is a shared interrupt */
write_seqlock(&xtime_lock);
while (((read_CRTR() - last_crtr) & AT91_ST_ALMV) >= LATCH) {
timer_tick(regs);
last_crtr = (last_crtr + LATCH) & AT91_ST_ALMV;
}
write_sequnlock(&xtime_lock);
return IRQ_HANDLED;
}
else
return IRQ_NONE; /* not handled */
}
static int
clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev)
{
u32 alm;
int status = 0;
BUG_ON(delta < 2);
alm = read_CRTR();
at91_st_write(AT91_ST_RTAR, alm);
at91_st_read(AT91_ST_SR);
alm += delta;
at91_st_write(AT91_ST_RTAR, alm);
return status;
}
static cycle_t read_clk32k(struct clocksource *cs)
{
return read_CRTR();
}
