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Merge pull request #8933 from gebart/pr/kinetis-pit-refactor

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kinetis: Refactor PIT timer driver implementation
This commit is contained in:
Loïc Dauphin 2018-05-29 11:09:55 +02:00 committed by GitHub
commit b7a8ba73a9
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1 changed files with 63 additions and 99 deletions
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162
cpu/kinetis/periph/timer.c
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@ -151,34 +151,6 @@ static inline void pit_start(uint8_t dev);
static inline void pit_stop(uint8_t dev); static inline void pit_stop(uint8_t dev);
static inline void pit_irq_handler(tim_t dev); static inline void pit_irq_handler(tim_t dev);
static inline void _pit_set_cb_config(uint8_t dev, timer_cb_t cb, void *arg)
{
/* set callback function */
pit[dev].isr_ctx.cb = cb;
pit[dev].isr_ctx.arg = arg;
}
/** use channel n-1 as prescaler */
static inline void _pit_set_prescaler(uint8_t ch, uint32_t freq)
{
/* Disable channel completely */
PIT->CHANNEL[ch].TCTRL = 0x0;
PIT->CHANNEL[ch].LDVAL = (PIT_BASECLOCK / freq) - 1;
/* Start the prescaler counter immediately */
PIT->CHANNEL[ch].TCTRL = (PIT_TCTRL_TEN_MASK);
}
static inline void _pit_set_counter(uint8_t dev)
{
const uint8_t ch = pit_config[dev].count_ch;
/* Disable channel completely */
PIT->CHANNEL[ch].TCTRL = 0x0;
PIT->CHANNEL[ch].LDVAL = pit[dev].ldval;
PIT->CHANNEL[ch].TFLG = PIT_TFLG_TIF_MASK;
/* Restore previous timer state */
PIT->CHANNEL[ch].TCTRL = pit[dev].tctrl;
}
static inline int pit_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg) static inline int pit_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg)
{ {
/* Turn on module clock gate */ /* Turn on module clock gate */
@ -188,32 +160,38 @@ static inline int pit_init(uint8_t dev, uint32_t freq, timer_cb_t cb, void *arg)
/* Disable IRQs to avoid race with ISR */ /* Disable IRQs to avoid race with ISR */
unsigned int mask = irq_disable(); unsigned int mask = irq_disable();
uint8_t count_ch = pit_config[dev].count_ch;
/* Clear configuration */ /* Clear configuration */
PIT->CHANNEL[pit_config[dev].count_ch].TCTRL = 0; PIT->CHANNEL[count_ch].TCTRL = 0;
/* Freeze timers during debug break, resume normal operations (clear MDIS) */ /* Freeze timers during debug break, resume normal operations (clear MDIS) */
PIT->MCR = PIT_MCR_FRZ_MASK; PIT->MCR = PIT_MCR_FRZ_MASK;
_pit_set_cb_config(dev, cb, arg); /* set callback function */
pit[dev].isr_ctx.cb = cb;
pit[dev].isr_ctx.arg = arg;
/* Clear IRQ flag */ /* Clear IRQ flag */
PIT->CHANNEL[pit_config[dev].count_ch].TFLG = PIT_TFLG_TIF_MASK; PIT->CHANNEL[count_ch].TFLG = PIT_TFLG_TIF_MASK;
#if KINETIS_PIT_COMBINED_IRQ #if KINETIS_PIT_COMBINED_IRQ
/* One IRQ for all channels */ /* One IRQ for all channels */
/* NVIC_ClearPendingIRQ(PIT_IRQn); */ /* does it make sense to clear this IRQ flag? */ /* NVIC_ClearPendingIRQ(PIT_IRQn); */ /* does it make sense to clear this IRQ flag? */
NVIC_EnableIRQ(PIT_IRQn); NVIC_EnableIRQ(PIT_IRQn);
#else #else
/* Refactor the below lines if there are any CPUs where the PIT IRQs are not sequential */ /* Refactor the below lines if there are any CPUs where the PIT IRQs are not sequential */
NVIC_ClearPendingIRQ(PIT0_IRQn + pit_config[dev].count_ch); NVIC_ClearPendingIRQ(PIT0_IRQn + count_ch);
NVIC_EnableIRQ(PIT0_IRQn + pit_config[dev].count_ch); NVIC_EnableIRQ(PIT0_IRQn + count_ch);
#endif #endif
/* Reset up-counter */ /* Reset up-counter */
pit[dev].count = PIT_MAX_VALUE; pit[dev].count = PIT_MAX_VALUE;
pit[dev].ldval = PIT_MAX_VALUE; PIT->CHANNEL[count_ch].LDVAL = PIT_MAX_VALUE;
pit[dev].tctrl = PIT_TCTRL_CHN_MASK | PIT_TCTRL_TEN_MASK; /* Disable prescaler channel */
_pit_set_prescaler(pit_config[dev].prescaler_ch, freq); PIT->CHANNEL[pit_config[dev].prescaler_ch].TCTRL = 0x0;
_pit_set_counter(dev); /* Load prescaler value */
PIT->CHANNEL[pit_config[dev].prescaler_ch].LDVAL = (PIT_BASECLOCK / freq) - 1;
/* Start the prescaler counter */
PIT->CHANNEL[pit_config[dev].prescaler_ch].TCTRL = (PIT_TCTRL_TEN_MASK);
PIT->CHANNEL[count_ch].TCTRL = PIT_TCTRL_CHN_MASK | PIT_TCTRL_TEN_MASK;
irq_restore(mask); irq_restore(mask);
return 0; return 0;
@ -224,17 +202,18 @@ static inline int pit_set(uint8_t dev, uint32_t timeout)
const uint8_t ch = pit_config[dev].count_ch; const uint8_t ch = pit_config[dev].count_ch;
/* Disable IRQs to minimize the number of lost ticks */ /* Disable IRQs to minimize the number of lost ticks */
unsigned int mask = irq_disable(); unsigned int mask = irq_disable();
pit[dev].ldval = timeout; /* Subtract if there was anything left on the counter */
pit[dev].tctrl = PIT_TCTRL_TIE_MASK | PIT_TCTRL_CHN_MASK | PIT_TCTRL_TEN_MASK; pit[dev].count -= PIT->CHANNEL[ch].CVAL;
/* Set new timeout */
PIT->CHANNEL[ch].TCTRL = 0;
PIT->CHANNEL[ch].LDVAL = timeout;
PIT->CHANNEL[ch].TFLG = PIT_TFLG_TIF_MASK;
PIT->CHANNEL[ch].TCTRL = PIT_TCTRL_TIE_MASK | PIT_TCTRL_CHN_MASK | PIT_TCTRL_TEN_MASK;
/* Add the new timeout offset to the up-counter */ /* Add the new timeout offset to the up-counter */
pit[dev].count += timeout; pit[dev].count += timeout;
if ((PIT->CHANNEL[ch].TCTRL & PIT_TCTRL_TEN_MASK) != 0) { /* Set the timer to reload the maximum value to be able to count the number
/* Timer is currently running */ * of overflow ticks inside the ISR */
uint32_t cval = PIT->CHANNEL[ch].CVAL; PIT->CHANNEL[ch].LDVAL = PIT_MAX_VALUE;
/* Subtract if there was anything left on the counter */
pit[dev].count -= cval;
_pit_set_counter(dev);
}
irq_restore(mask); irq_restore(mask);
return 0; return 0;
} }
@ -244,16 +223,18 @@ static inline int pit_set_absolute(uint8_t dev, uint32_t target)
uint8_t ch = pit_config[dev].count_ch; uint8_t ch = pit_config[dev].count_ch;
/* Disable IRQs to minimize the number of lost ticks */ /* Disable IRQs to minimize the number of lost ticks */
unsigned int mask = irq_disable(); unsigned int mask = irq_disable();
uint32_t now = pit_read(dev); uint32_t now = pit[dev].count - PIT->CHANNEL[ch].CVAL;
uint32_t offset = target - now; uint32_t offset = target - now;
pit[dev].ldval = offset; /* Set new timeout */
pit[dev].tctrl = PIT_TCTRL_TIE_MASK | PIT_TCTRL_CHN_MASK | PIT_TCTRL_TEN_MASK; PIT->CHANNEL[ch].TCTRL = 0;
PIT->CHANNEL[ch].LDVAL = offset;
PIT->CHANNEL[ch].TFLG = PIT_TFLG_TIF_MASK;
PIT->CHANNEL[ch].TCTRL = PIT_TCTRL_TIE_MASK | PIT_TCTRL_CHN_MASK | PIT_TCTRL_TEN_MASK;
/* Set the new target time in the up-counter */ /* Set the new target time in the up-counter */
pit[dev].count = target; pit[dev].count = target;
if ((PIT->CHANNEL[ch].TCTRL & PIT_TCTRL_TEN_MASK) != 0) { /* Set the timer to reload the maximum value to be able to count the number
_pit_set_counter(dev); * of overflow ticks inside the ISR */
} PIT->CHANNEL[ch].LDVAL = PIT_MAX_VALUE;
irq_restore(mask); irq_restore(mask);
return 0; return 0;
} }
@ -263,78 +244,61 @@ static inline int pit_clear(uint8_t dev)
uint8_t ch = pit_config[dev].count_ch; uint8_t ch = pit_config[dev].count_ch;
/* Disable IRQs to minimize the number of lost ticks */ /* Disable IRQs to minimize the number of lost ticks */
unsigned int mask = irq_disable(); unsigned int mask = irq_disable();
/* Subtract if there was anything left on the counter */
pit[dev].ldval = PIT_MAX_VALUE; pit[dev].count -= PIT->CHANNEL[ch].CVAL;
pit[dev].tctrl = PIT_TCTRL_CHN_MASK | PIT_TCTRL_TEN_MASK; /* No need to add PIT_MAX_VALUE + 1 to the counter because of modulo 2**32 */
/* pit[dev].count += PIT_MAX_VALUE + 1; */ /* == 0 (mod 2**32) */ /* Set a long timeout */
PIT->CHANNEL[ch].TCTRL = 0;
if ((PIT->CHANNEL[ch].TCTRL & PIT_TCTRL_TEN_MASK) != 0) { PIT->CHANNEL[ch].LDVAL = PIT_MAX_VALUE;
/* Timer is currently running */ PIT->CHANNEL[ch].TFLG = PIT_TFLG_TIF_MASK;
uint32_t cval = PIT->CHANNEL[ch].CVAL; PIT->CHANNEL[ch].TCTRL = PIT_TCTRL_CHN_MASK | PIT_TCTRL_TEN_MASK;
/* Subtract if there was anything left on the counter */
pit[dev].count -= cval;
/* Set a long timeout */
_pit_set_counter(ch);
}
irq_restore(mask); irq_restore(mask);
return 0; return 0;
} }
/* CVAL is unreliable if the timer is not enabled (TCTRL_TEN bit clear),
* by stopping the prescaler instead of the counter channel we avoid this issue,
* and additionally do not need to worry about saving the control registers or
* recomputing the target time when starting the timer */
static inline uint32_t pit_read(uint8_t dev) static inline uint32_t pit_read(uint8_t dev)
{ {
uint8_t ch = pit_config[dev].count_ch; uint8_t ch = pit_config[dev].count_ch;
if ((PIT->CHANNEL[ch].TCTRL & PIT_TCTRL_TEN_MASK) != 0) { return pit[dev].count - PIT->CHANNEL[ch].CVAL;
/* Timer running */
return pit[dev].count - PIT->CHANNEL[ch].CVAL;
}
else {
/* Timer stopped */
return pit[dev].count;
}
} }
static inline void pit_start(uint8_t dev) static inline void pit_start(uint8_t dev)
{ {
uint8_t ch = pit_config[dev].count_ch; uint8_t ch = pit_config[dev].prescaler_ch;
if ((PIT->CHANNEL[ch].TCTRL & PIT_TCTRL_TEN_MASK) != 0) { PIT->CHANNEL[ch].TCTRL = PIT_TCTRL_TEN_MASK;
/* Already running */
return;
}
PIT->CHANNEL[ch].LDVAL = pit[dev].ldval;
pit[dev].count += pit[dev].ldval;
PIT->CHANNEL[ch].TCTRL = pit[dev].tctrl;
} }
static inline void pit_stop(uint8_t dev) static inline void pit_stop(uint8_t dev)
{ {
uint8_t ch = pit_config[dev].count_ch; uint8_t ch = pit_config[dev].prescaler_ch;
if ((PIT->CHANNEL[ch].TCTRL & PIT_TCTRL_TEN_MASK) == 0) {
/* Already stopped */
return;
}
uint32_t cval = PIT->CHANNEL[ch].CVAL;
pit[dev].tctrl = PIT->CHANNEL[ch].TCTRL;
PIT->CHANNEL[ch].TCTRL = 0; PIT->CHANNEL[ch].TCTRL = 0;
pit[dev].count -= cval;
pit[dev].ldval = cval;
} }
static inline void pit_irq_handler(tim_t dev) static inline void pit_irq_handler(tim_t dev)
{ {
uint8_t ch = pit_config[_pit_index(dev)].count_ch; uint8_t ch = pit_config[_pit_index(dev)].count_ch;
pit_t *pit_ctx = &pit[_pit_index(dev)]; pit_t *pit_ctx = &pit[_pit_index(dev)];
pit_ctx->ldval = PIT_MAX_VALUE; if (!PIT->CHANNEL[ch].TFLG) {
pit_ctx->count += PIT_MAX_VALUE; DEBUG("PIT%u!TFLG\n", (unsigned)dev);
pit_ctx->tctrl = PIT_TCTRL_CHN_MASK | PIT_TCTRL_TEN_MASK; return;
_pit_set_counter(_pit_index(dev)); }
/* Add the overflow amount to the counter before resetting */
/* (this may be > 0 if the IRQ handler was delayed e.g. by irq_disable etc.) */
pit_ctx->count += PIT->CHANNEL[ch].LDVAL - PIT->CHANNEL[ch].CVAL;
/* inline pit_clear */
PIT->CHANNEL[ch].TCTRL = 0;
PIT->CHANNEL[ch].LDVAL = PIT_MAX_VALUE;
PIT->CHANNEL[ch].TFLG = PIT_TFLG_TIF_MASK;
PIT->CHANNEL[ch].TCTRL = PIT_TCTRL_CHN_MASK | PIT_TCTRL_TEN_MASK;
if (pit_ctx->isr_ctx.cb != NULL) { if (pit_ctx->isr_ctx.cb != NULL) {
pit_ctx->isr_ctx.cb(pit_ctx->isr_ctx.arg, 0); pit_ctx->isr_ctx.cb(pit_ctx->isr_ctx.arg, 0);
} }
PIT->CHANNEL[ch].TFLG = PIT_TFLG_TIF_MASK;
cortexm_isr_end(); cortexm_isr_end();
} }