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newlib: implement gettimeofday using of esp_timer

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This commit is contained in:
Ivan Grokhotkov 2017-08-07 23:28:36 +08:00
parent 857a29872d
commit 42e9d49bb1
1 changed files with 6 additions and 47 deletions
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53
components/newlib/time.c
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@ -26,6 +26,7 @@
#include "esp_attr.h" #include "esp_attr.h"
#include "esp_intr_alloc.h" #include "esp_intr_alloc.h"
#include "esp_clk.h" #include "esp_clk.h"
#include "../esp32/esp_timer.h"
#include "soc/soc.h" #include "soc/soc.h"
#include "soc/rtc.h" #include "soc/rtc.h"
#include "soc/rtc_cntl_reg.h" #include "soc/rtc_cntl_reg.h"
@ -79,30 +80,9 @@ static uint64_t s_boot_time;
static _lock_t s_boot_time_lock; static _lock_t s_boot_time_lock;
#endif #endif
#ifdef WITH_FRC1 #ifdef WITH_RTC
#define FRC1_PRESCALER 16 uint64_t s_microseconds_offset;
#define FRC1_PRESCALER_CTL 2 #endif
#define FRC1_TICK_FREQ (APB_CLK_FREQ / FRC1_PRESCALER)
#define FRC1_TICKS_PER_US (FRC1_TICK_FREQ / 1000000)
#define FRC1_ISR_PERIOD_US (FRC_TIMER_LOAD_VALUE(0) / FRC1_TICKS_PER_US)
// Counter frequency will be APB_CLK_FREQ / 16 = 5 MHz
// 1 tick = 0.2 us
// Timer has 23 bit counter, so interrupt will fire each 1677721.6 microseconds.
// This is not a whole number, so timer will drift by 0.3 ppm due to rounding error.
static volatile uint64_t s_microseconds = 0;
static void IRAM_ATTR frc_timer_isr()
{
// Write to FRC_TIMER_INT_REG may not take effect in some cases (root cause TBD)
// This extra write works around this issue.
// FRC_TIMER_LOAD_REG(0) is used here, but any other DPORT register address can also be used.
WRITE_PERI_REG(FRC_TIMER_LOAD_REG(0), FRC_TIMER_LOAD_VALUE(0));
WRITE_PERI_REG(FRC_TIMER_INT_REG(0), FRC_TIMER_INT_CLR);
s_microseconds += FRC1_ISR_PERIOD_US;
}
#endif // WITH_FRC1
#if defined(WITH_RTC) || defined(WITH_FRC1) #if defined(WITH_RTC) || defined(WITH_FRC1)
static void set_boot_time(uint64_t time_us) static void set_boot_time(uint64_t time_us)
@ -162,20 +142,8 @@ void esp_setup_time_syscalls()
#if defined( WITH_FRC1 ) #if defined( WITH_FRC1 )
#if defined( WITH_RTC ) #if defined( WITH_RTC )
// initialize time from RTC clock // initialize time from RTC clock
s_microseconds = get_rtc_time_us(); s_microseconds_offset = get_rtc_time_us() - esp_timer_get_time();
#endif //WITH_RTC #endif //WITH_RTC
// set up timer
WRITE_PERI_REG(FRC_TIMER_CTRL_REG(0), \
FRC_TIMER_AUTOLOAD | \
(FRC1_PRESCALER_CTL << FRC_TIMER_PRESCALER_S) | \
FRC_TIMER_EDGE_INT);
WRITE_PERI_REG(FRC_TIMER_LOAD_REG(0), FRC_TIMER_LOAD_VALUE(0));
SET_PERI_REG_MASK(FRC_TIMER_CTRL_REG(0),
FRC_TIMER_ENABLE | \
FRC_TIMER_INT_ENABLE);
esp_intr_alloc(ETS_TIMER1_INTR_SOURCE, 0, &frc_timer_isr, NULL, NULL);
#endif // WITH_FRC1 #endif // WITH_FRC1
} }
@ -196,16 +164,7 @@ static uint64_t get_time_since_boot()
{ {
uint64_t microseconds = 0; uint64_t microseconds = 0;
#ifdef WITH_FRC1 #ifdef WITH_FRC1
uint32_t timer_ticks_before = READ_PERI_REG(FRC_TIMER_COUNT_REG(0)); microseconds = s_microseconds_offset + esp_timer_get_time();
microseconds = s_microseconds;
uint32_t timer_ticks_after = READ_PERI_REG(FRC_TIMER_COUNT_REG(0));
if (timer_ticks_after > timer_ticks_before) {
// overflow happened at some point between getting
// timer_ticks_before and timer_ticks_after
// microseconds value is ambiguous, get a new one
microseconds = s_microseconds;
}
microseconds += (FRC_TIMER_LOAD_VALUE(0) - timer_ticks_after) / FRC1_TICKS_PER_US;
#elif defined(WITH_RTC) #elif defined(WITH_RTC)
microseconds = get_rtc_time_us(); microseconds = get_rtc_time_us();
#endif #endif