alex/esp-idf
1
0
Fork 0
mirror of https://github.com/espressif/esp-idf.git synced 2025-08-08 04:02:27 +00:00
Code Issues Packages Projects Releases Wiki Activity

esp_timer: add support for frequency scaling

Browse Source
This commit is contained in:
Ivan Grokhotkov
2017-10-09 15:24:51 +08:00
parent 3f818f4862
commit eb0c34e5c9
3 changed files with 80 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

58
components/esp32/esp_timer_esp32.c
View File

@@ -19,6 +19,7 @@
#include "esp_attr.h"
#include "esp_intr_alloc.h"
#include "esp_log.h"
#include "esp_clk.h"
#include "esp_timer_impl.h"
#include "soc/frc_timer_reg.h"
#include "soc/rtc.h"
@@ -112,6 +113,14 @@ static uint32_t s_timer_us_per_overflow;
// will not increment s_time_base_us if this flag is set.
static bool s_mask_overflow;
#ifdef CONFIG_PM_DFS_USE_RTC_TIMER_REF
// If DFS is enabled, upon the first frequency change this value is set to the
// difference between esp_timer value and RTC timer value. On every subsequent
// frequency change, s_time_base_us is adjusted to maintain the same difference
// between esp_timer and RTC timer. (All mentioned values are in microseconds.)
static uint64_t s_rtc_time_diff = 0;
#endif
// Spinlock used to protect access to static variables above and to the hardware
// registers.
portMUX_TYPE s_time_update_lock = portMUX_INITIALIZER_UNLOCKED;
@@ -208,6 +217,55 @@ static void IRAM_ATTR timer_alarm_isr(void *arg)
(*s_alarm_handler)(arg);
}
void IRAM_ATTR esp_timer_impl_update_apb_freq(uint32_t apb_ticks_per_us)
{
portENTER_CRITICAL(&s_time_update_lock);
/* Bail out if the timer is not initialized yet */
if (s_timer_interrupt_handle == NULL) {
portEXIT_CRITICAL(&s_time_update_lock);
return;
}
uint32_t new_ticks_per_us = apb_ticks_per_us / TIMER_DIV;
uint32_t alarm = REG_READ(FRC_TIMER_ALARM_REG(1));
uint32_t count = REG_READ(FRC_TIMER_COUNT_REG(1));
uint64_t ticks_to_alarm = alarm - count;
uint64_t new_ticks = (ticks_to_alarm * new_ticks_per_us) / s_timer_ticks_per_us;
uint32_t new_alarm_val;
if (alarm > count && new_ticks <= FRC_TIMER_LOAD_VALUE(1)) {
new_alarm_val = new_ticks;
} else {
new_alarm_val = ALARM_OVERFLOW_VAL;
if (alarm != ALARM_OVERFLOW_VAL) {
s_mask_overflow = true;
}
}
REG_WRITE(FRC_TIMER_ALARM_REG(1), new_alarm_val);
REG_WRITE(FRC_TIMER_LOAD_REG(1), 0);
s_time_base_us += count / s_timer_ticks_per_us;
#ifdef CONFIG_PM_DFS_USE_RTC_TIMER_REF
// Due to the extra time required to read RTC time, don't attempt this
// adjustment when switching to a higher frequency (which usually
// happens in an interrupt).
if (new_ticks_per_us < s_timer_ticks_per_us) {
uint64_t rtc_time = esp_clk_rtc_time();
uint64_t new_rtc_time_diff = s_time_base_us - rtc_time;
if (s_rtc_time_diff != 0) {
uint64_t correction = new_rtc_time_diff - s_rtc_time_diff;
s_time_base_us -= correction;
} else {
s_rtc_time_diff = new_rtc_time_diff;
}
}
#endif // CONFIG_PM_DFS_USE_RTC_TIMER_REF
s_timer_ticks_per_us = new_ticks_per_us;
s_timer_us_per_overflow = FRC_TIMER_LOAD_VALUE(1) / new_ticks_per_us;
portEXIT_CRITICAL(&s_time_update_lock);
}
esp_err_t esp_timer_impl_init(intr_handler_t alarm_handler)
{