OVMS3-idf/components/soc/esp32/rtc_time.c
wangmengyang 22e21b38f7 component/bt: implement bluetooth modem sleep mode, one mode for BLE only and another for dual mode bluetooth
1. provide options for bluetooth low power mode
2. provide two options for bluetooth low power clock: main XTAL and external 32kHz XTAL
3. provide function and callbacks to control bluetooth low power mode, including enable/disable sleep, software wakeup request, low power clock settings, check power state, etc
4. modify vhci API vhci_host_send_packet to use blocking mode
5. note that DFS and bluetooth modem sleep can not be used together currently.
2018-05-19 15:37:26 +08:00

156 lines
6.3 KiB
C

// Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <stdint.h>
#include "rom/ets_sys.h"
#include "soc/rtc.h"
#include "soc/rtc_cntl_reg.h"
#include "soc/timer_group_reg.h"
#define MHZ (1000000)
/* Calibration of RTC_SLOW_CLK is performed using a special feature of TIMG0.
* This feature counts the number of XTAL clock cycles within a given number of
* RTC_SLOW_CLK cycles.
*
* Slow clock calibration feature has two modes of operation: one-off and cycling.
* In cycling mode (which is enabled by default on SoC reset), counting of XTAL
* cycles within RTC_SLOW_CLK cycle is done continuously. Cycling mode is enabled
* using TIMG_RTC_CALI_START_CYCLING bit. In one-off mode counting is performed
* once, and TIMG_RTC_CALI_RDY bit is set when counting is done. One-off mode is
* enabled using TIMG_RTC_CALI_START bit.
*/
/**
* @brief Clock calibration function used by rtc_clk_cal and rtc_clk_cal_ratio
* @param cal_clk which clock to calibrate
* @param slowclk_cycles number of slow clock cycles to count
* @return number of XTAL clock cycles within the given number of slow clock cycles
*/
static uint32_t rtc_clk_cal_internal(rtc_cal_sel_t cal_clk, uint32_t slowclk_cycles)
{
/* Enable requested clock (150k clock is always on) */
int dig_32k_xtal_state = REG_GET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_XTAL32K_EN);
if (cal_clk == RTC_CAL_32K_XTAL && !dig_32k_xtal_state) {
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_XTAL32K_EN, 1);
}
if (cal_clk == RTC_CAL_8MD256) {
SET_PERI_REG_MASK(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_CLK8M_D256_EN);
}
/* Prepare calibration */
REG_SET_FIELD(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_CLK_SEL, cal_clk);
CLEAR_PERI_REG_MASK(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_START_CYCLING);
REG_SET_FIELD(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_MAX, slowclk_cycles);
/* Figure out how long to wait for calibration to finish */
uint32_t expected_freq;
rtc_slow_freq_t slow_freq = REG_GET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_ANA_CLK_RTC_SEL);
if (cal_clk == RTC_CAL_32K_XTAL ||
(cal_clk == RTC_CAL_RTC_MUX && slow_freq == RTC_SLOW_FREQ_32K_XTAL)) {
expected_freq = 32768; /* standard 32k XTAL */
} else if (cal_clk == RTC_CAL_8MD256 ||
(cal_clk == RTC_CAL_RTC_MUX && slow_freq == RTC_SLOW_FREQ_8MD256)) {
expected_freq = RTC_FAST_CLK_FREQ_APPROX / 256;
} else {
expected_freq = 150000; /* 150k internal oscillator */
}
uint32_t us_time_estimate = (uint32_t) (((uint64_t) slowclk_cycles) * MHZ / expected_freq);
/* Start calibration */
CLEAR_PERI_REG_MASK(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_START);
SET_PERI_REG_MASK(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_START);
/* Wait the expected time calibration should take.
* TODO: if running under RTOS, and us_time_estimate > RTOS tick, use the
* RTOS delay function.
*/
ets_delay_us(us_time_estimate);
/* Wait for calibration to finish up to another us_time_estimate */
int timeout_us = us_time_estimate;
while (!GET_PERI_REG_MASK(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_RDY) &&
timeout_us > 0) {
timeout_us--;
ets_delay_us(1);
}
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_XTAL32K_EN, dig_32k_xtal_state);
if (cal_clk == RTC_CAL_8MD256) {
CLEAR_PERI_REG_MASK(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_DIG_CLK8M_D256_EN);
}
if (timeout_us == 0) {
/* timed out waiting for calibration */
return 0;
}
return REG_GET_FIELD(TIMG_RTCCALICFG1_REG(0), TIMG_RTC_CALI_VALUE);
}
uint32_t rtc_clk_cal_ratio(rtc_cal_sel_t cal_clk, uint32_t slowclk_cycles)
{
uint64_t xtal_cycles = rtc_clk_cal_internal(cal_clk, slowclk_cycles);
uint64_t ratio_64 = ((xtal_cycles << RTC_CLK_CAL_FRACT)) / slowclk_cycles;
uint32_t ratio = (uint32_t)(ratio_64 & UINT32_MAX);
return ratio;
}
uint32_t rtc_clk_cal(rtc_cal_sel_t cal_clk, uint32_t slowclk_cycles)
{
rtc_xtal_freq_t xtal_freq = rtc_clk_xtal_freq_get();
uint64_t xtal_cycles = rtc_clk_cal_internal(cal_clk, slowclk_cycles);
uint64_t divider = ((uint64_t)xtal_freq) * slowclk_cycles;
uint64_t period_64 = ((xtal_cycles << RTC_CLK_CAL_FRACT) + divider / 2 - 1) / divider;
uint32_t period = (uint32_t)(period_64 & UINT32_MAX);
return period;
}
uint64_t rtc_time_us_to_slowclk(uint64_t time_in_us, uint32_t period)
{
/* Overflow will happen in this function if time_in_us >= 2^45, which is about 400 days.
* TODO: fix overflow.
*/
return (time_in_us << RTC_CLK_CAL_FRACT) / period;
}
uint64_t rtc_time_slowclk_to_us(uint64_t rtc_cycles, uint32_t period)
{
return (rtc_cycles * period) >> RTC_CLK_CAL_FRACT;
}
uint64_t rtc_time_get()
{
SET_PERI_REG_MASK(RTC_CNTL_TIME_UPDATE_REG, RTC_CNTL_TIME_UPDATE);
while (GET_PERI_REG_MASK(RTC_CNTL_TIME_UPDATE_REG, RTC_CNTL_TIME_VALID) == 0) {
ets_delay_us(1); // might take 1 RTC slowclk period, don't flood RTC bus
}
SET_PERI_REG_MASK(RTC_CNTL_INT_CLR_REG, RTC_CNTL_TIME_VALID_INT_CLR);
uint64_t t = READ_PERI_REG(RTC_CNTL_TIME0_REG);
t |= ((uint64_t) READ_PERI_REG(RTC_CNTL_TIME1_REG)) << 32;
return t;
}
void rtc_clk_wait_for_slow_cycle()
{
REG_CLR_BIT(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_START_CYCLING | TIMG_RTC_CALI_START);
REG_CLR_BIT(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_RDY);
REG_SET_FIELD(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_CLK_SEL, RTC_CAL_RTC_MUX);
/* Request to run calibration for 0 slow clock cycles.
* RDY bit will be set on the nearest slow clock cycle.
*/
REG_SET_FIELD(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_MAX, 0);
REG_SET_BIT(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_START);
ets_delay_us(1); /* RDY needs some time to go low */
while (!GET_PERI_REG_MASK(TIMG_RTCCALICFG_REG(0), TIMG_RTC_CALI_RDY)) {
ets_delay_us(1);
}
}