esp-open-rtos/core/include/esp/timer_private.h
2015-08-19 11:34:18 -07:00

260 lines
7.6 KiB
C++

/* Private header parts of the timer API implementation
*
* Part of esp-open-rtos
* Copyright (C) 2015 Superhouse Automation Pty Ltd
* BSD Licensed as described in the file LICENSE
*/
#ifndef _ESP_TIMER_PRIVATE_H
#define _ESP_TIMER_PRIVATE_H
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include "esp/dport_regs.h"
/* Timer divisor index to max frequency */
#define _FREQ_DIV1 (80*1000*1000)
#define _FREQ_DIV16 (5*1000*1000)
#define _FREQ_DIV256 312500
const static uint32_t IROM _TIMER_FREQS[] = { _FREQ_DIV1, _FREQ_DIV16, _FREQ_DIV256 };
/* Timer divisor index to divisor value */
const static uint32_t IROM _TIMER_DIV_VAL[] = { 1, 16, 256 };
INLINED uint32_t timer_get_count(const timer_frc_t frc)
{
return TIMER(frc).COUNT;
}
INLINED uint32_t timer_get_load(const timer_frc_t frc)
{
return TIMER(frc).LOAD;
}
INLINED void timer_set_load(const timer_frc_t frc, const uint32_t load)
{
TIMER(frc).LOAD = load;
}
INLINED uint32_t timer_max_load(const timer_frc_t frc)
{
return (frc == FRC1) ? TIMER_FRC1_MAX_LOAD : UINT32_MAX;
}
INLINED void timer_set_divider(const timer_frc_t frc, const timer_clkdiv_t div)
{
if(div < TIMER_CLKDIV_1 || div > TIMER_CLKDIV_256)
return;
TIMER(frc).CTRL = SET_FIELD(TIMER(frc).CTRL, TIMER_CTRL_CLKDIV, div);
}
INLINED void timer_set_interrupts(const timer_frc_t frc, bool enable)
{
const uint32_t dp_bit = (frc == FRC1) ? DPORT_INT_ENABLE_FRC1 : DPORT_INT_ENABLE_FRC2;
const uint32_t int_mask = BIT((frc == FRC1) ? INUM_TIMER_FRC1 : INUM_TIMER_FRC2);
if(enable) {
DPORT.INT_ENABLE |= dp_bit;
_xt_isr_unmask(int_mask);
} else {
DPORT.INT_ENABLE &= ~dp_bit;
_xt_isr_mask(int_mask);
}
}
INLINED void timer_set_run(const timer_frc_t frc, const bool run)
{
if (run)
TIMER(frc).CTRL |= TIMER_CTRL_RUN;
else
TIMER(frc).CTRL &= ~TIMER_CTRL_RUN;
}
INLINED bool timer_get_run(const timer_frc_t frc)
{
return TIMER(frc).CTRL & TIMER_CTRL_RUN;
}
INLINED void timer_set_reload(const timer_frc_t frc, const bool reload)
{
if (reload)
TIMER(frc).CTRL |= TIMER_CTRL_RELOAD;
else
TIMER(frc).CTRL &= ~TIMER_CTRL_RELOAD;
}
INLINED bool timer_get_reload(const timer_frc_t frc)
{
return TIMER(frc).CTRL & TIMER_CTRL_RELOAD;
}
INLINED timer_clkdiv_t timer_freq_to_div(uint32_t freq)
{
/*
try to maintain resolution without risking overflows.
these values are a bit arbitrary at the moment! */
if(freq > 100*1000)
return TIMER_CLKDIV_1;
else if(freq > 100)
return TIMER_CLKDIV_16;
else
return TIMER_CLKDIV_256;
}
/* timer_timer_to_count implementation - inline if all args are constant, call normally otherwise */
INLINED uint32_t _timer_freq_to_count_impl(const timer_frc_t frc, const uint32_t freq, const timer_clkdiv_t div)
{
if(div < TIMER_CLKDIV_1 || div > TIMER_CLKDIV_256)
return 0; /* invalid divider */
if(freq > _TIMER_FREQS[div])
return 0; /* out of range for given divisor */
uint64_t counts = _TIMER_FREQS[div]/freq;
return counts;
}
uint32_t _timer_freq_to_count_runtime(const timer_frc_t frc, const uint32_t freq, const timer_clkdiv_t div);
INLINED uint32_t timer_freq_to_count(const timer_frc_t frc, const uint32_t freq, const timer_clkdiv_t div)
{
if(__builtin_constant_p(frc) && __builtin_constant_p(freq) && __builtin_constant_p(div))
return _timer_freq_to_count_impl(frc, freq, div);
else
return _timer_freq_to_count_runtime(frc, freq, div);
}
INLINED timer_clkdiv_t timer_time_to_div(uint32_t us)
{
/*
try to maintain resolution without risking overflows. Similar to
timer_freq_to_div, these values are a bit arbitrary at the
moment! */
if(us < 1000)
return TIMER_CLKDIV_1;
else if(us < 10*1000)
return TIMER_CLKDIV_16;
else
return TIMER_CLKDIV_256;
}
/* timer_timer_to_count implementation - inline if all args are constant, call normally otherwise */
INLINED uint32_t _timer_time_to_count_impl(const timer_frc_t frc, uint32_t us, const timer_clkdiv_t div)
{
if(div < TIMER_CLKDIV_1 || div > TIMER_CLKDIV_256)
return 0; /* invalid divider */
const uint32_t TIMER_MAX = timer_max_load(frc);
if(div != TIMER_CLKDIV_256) /* timer tick in MHz */
{
/* timer is either 80MHz or 5MHz, so either 80 or 5 MHz counts per us */
const uint32_t counts_per_us = ((div == TIMER_CLKDIV_1) ? _FREQ_DIV1 : _FREQ_DIV16)/1000/1000;
if(us > TIMER_MAX/counts_per_us)
return 0; /* Multiplying us by mhz_per_count will overflow TIMER_MAX */
return us*counts_per_us;
}
else /* /256 divider, 312.5kHz freq so need to scale up */
{
/* derived from naive floating point equation that we can't use:
counts = (us/1000/1000)*_FREQ_DIV256;
counts = (us/2000)*(_FREQ_DIV256/500);
counts = us*(_FREQ_DIV256/500)/2000;
*/
const uint32_t scalar = _FREQ_DIV256/500;
if(us > 1+UINT32_MAX/scalar)
return 0; /* Multiplying us by _FREQ_DIV256/500 will overflow uint32_t */
uint32_t counts = (us*scalar)/2000;
if(counts > TIMER_MAX)
return 0; /* counts value too high for timer type */
return counts;
}
}
uint32_t _timer_time_to_count_runtime(const timer_frc_t frc, uint32_t us, const timer_clkdiv_t div);
INLINED uint32_t timer_time_to_count(const timer_frc_t frc, uint32_t us, const timer_clkdiv_t div)
{
if(__builtin_constant_p(frc) && __builtin_constant_p(us) && __builtin_constant_p(div))
return _timer_time_to_count_impl(frc, us, div);
else
return _timer_time_to_count_runtime(frc, us, div);
}
/* timer_set_frequency implementation - inline if all args are constant, call normally otherwise */
INLINED bool _timer_set_frequency_impl(const timer_frc_t frc, uint32_t freq)
{
uint32_t counts = 0;
timer_clkdiv_t div = timer_freq_to_div(freq);
counts = timer_freq_to_count(frc, freq, div);
if(counts == 0)
{
printf("ABORT: No counter for timer %u frequency %lu\r\n", frc, freq);
abort();
}
timer_set_divider(frc, div);
if(frc == FRC1)
{
timer_set_load(frc, counts);
timer_set_reload(frc, true);
}
else /* FRC2 */
{
/* assume that if this overflows it'll wrap, so we'll get desired behaviour */
TIMER(1).ALARM = counts + TIMER(1).COUNT;
}
return true;
}
bool _timer_set_frequency_runtime(const timer_frc_t frc, uint32_t freq);
INLINED bool timer_set_frequency(const timer_frc_t frc, uint32_t freq)
{
if(__builtin_constant_p(frc) && __builtin_constant_p(freq))
return _timer_set_frequency_impl(frc, freq);
else
return _timer_set_frequency_runtime(frc, freq);
}
/* timer_set_timeout implementation - inline if all args are constant, call normally otherwise */
INLINED bool _timer_set_timeout_impl(const timer_frc_t frc, uint32_t us)
{
uint32_t counts = 0;
timer_clkdiv_t div = timer_time_to_div(us);
counts = timer_time_to_count(frc, us, div);
if(counts == 0)
return false; /* can't set frequency */
timer_set_divider(frc, div);
if(frc == FRC1)
{
timer_set_load(frc, counts);
}
else /* FRC2 */
{
TIMER(1).ALARM = counts + TIMER(1).COUNT;
}
return true;
}
bool _timer_set_timeout_runtime(const timer_frc_t frc, uint32_t us);
INLINED bool timer_set_timeout(const timer_frc_t frc, uint32_t us)
{
if(__builtin_constant_p(frc) && __builtin_constant_p(us))
return _timer_set_timeout_impl(frc, us);
else
return _timer_set_timeout_runtime(frc, us);
}
#endif