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OVMS3-idf/components/soc/esp32/rtc_clk.c
Ivan Grokhotkov 07543dfec4 soc/rtc: wait for SLOW_CLK cycle when switching CPU clock 
Previous implementation waited for 20us after setting
RTC_CNTL_SOC_CLK_SEL_XTL register, using ets_delay_us, assuming that
the CPU was running at XTAL frequency. In reality, clock switch happened
on the next RTC_SLOW_CLK cycle, and CPU could be running at the previous
frequency (for example, 240 MHz) until then.
ets_delay_us would wait for 20 us * 40 cycles per us = 800 CPU cycles
(assuming 40 MHz XTAL; even less with a 26 MHz XTAL).
But if CPU was running at 240 MHz, 800 cycles would pass in just 3.3us,
while SLOW_CLK cycle could happen as much as 1/150kHz = 6.7us after
RTC_CNTL_SOC_CLK_SEL_XTL was set. So the software would not actually wait
long enough for the clock switch to happen, and would disable the PLL
while CPU was still clocked from PLL, leading to a halt.

This implementation uses rtc_clk_wait_for_slow_cycle() function to wait
until the clock switch, removing the need to wait for a fixed number of
CPU cycles.
2017-11-09 15:51:14 +08:00

575 lines
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// 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 <stdbool.h>
#include <stdint.h>
#include <stddef.h>
#include <assert.h>
#include "rom/ets_sys.h"
#include "rom/rtc.h"
#include "rom/uart.h"
#include "soc/rtc.h"
#include "soc/rtc_cntl_reg.h"
#include "soc/rtc_io_reg.h"
#include "soc/sens_reg.h"
#include "soc/dport_reg.h"
#include "soc/efuse_reg.h"
#include "soc/apb_ctrl_reg.h"
#include "i2c_rtc_clk.h"
#include "soc_log.h"
#include "sdkconfig.h"
#define MHZ (1000000)
/* Frequency of the 8M oscillator is 8.5MHz +/- 5%, at the default DCAP setting */
#define RTC_FAST_CLK_FREQ_8M 8500000
#define RTC_SLOW_CLK_FREQ_150K 150000
#define RTC_SLOW_CLK_FREQ_8MD256 (RTC_FAST_CLK_FREQ_8M / 256)
#define RTC_SLOW_CLK_FREQ_32K 32768
static const char* TAG = "rtc_clk";
/* Various constants related to the analog internals of the chip.
* Defined here because they don't have any use outside of this file.
*/
#define BBPLL_ENDIV5_VAL_320M 0x43
#define BBPLL_BBADC_DSMP_VAL_320M 0x84
#define BBPLL_ENDIV5_VAL_480M 0xc3
#define BBPLL_BBADC_DSMP_VAL_480M 0x74
#define APLL_SDM_STOP_VAL_1 0x09
#define APLL_SDM_STOP_VAL_2_REV0 0x69
#define APLL_SDM_STOP_VAL_2_REV1 0x49
#define APLL_CAL_DELAY_1 0x0f
#define APLL_CAL_DELAY_2 0x3f
#define APLL_CAL_DELAY_3 0x1f
#define XTAL_32K_DAC_VAL 1
#define XTAL_32K_DRES_VAL 3
#define XTAL_32K_DBIAS_VAL 0
#define XTAL_32K_BOOTSTRAP_DAC_VAL 3
#define XTAL_32K_BOOTSTRAP_DRES_VAL 3
#define XTAL_32K_BOOTSTRAP_DBIAS_VAL 0
#define XTAL_32K_BOOTSTRAP_TIME_US 7
/* Delays for various clock sources to be enabled/switched.
* All values are in microseconds.
* TODO: some of these are excessive, and should be reduced.
*/
#define DELAY_PLL_DBIAS_RAISE 3
#define DELAY_PLL_ENABLE_WITH_150K 80
#define DELAY_PLL_ENABLE_WITH_32K 160
#define DELAY_FAST_CLK_SWITCH 3
#define DELAY_SLOW_CLK_SWITCH 300
#define DELAY_8M_ENABLE 50
/* Number of 8M/256 clock cycles to use for XTAL frequency estimation.
* 10 cycles will take approximately 300 microseconds.
*/
#define XTAL_FREQ_EST_CYCLES 10
static void rtc_clk_32k_enable_internal(int dac, int dres, int dbias)
{
SET_PERI_REG_MASK(RTC_IO_XTAL_32K_PAD_REG, RTC_IO_X32N_MUX_SEL | RTC_IO_X32P_MUX_SEL);
CLEAR_PERI_REG_MASK(RTC_IO_XTAL_32K_PAD_REG,
RTC_IO_X32P_RDE | RTC_IO_X32P_RUE | RTC_IO_X32N_RUE |
RTC_IO_X32N_RDE | RTC_IO_X32N_MUX_SEL | RTC_IO_X32P_MUX_SEL);
REG_SET_FIELD(RTC_IO_XTAL_32K_PAD_REG, RTC_IO_DAC_XTAL_32K, dac);
REG_SET_FIELD(RTC_IO_XTAL_32K_PAD_REG, RTC_IO_DRES_XTAL_32K, dres);
REG_SET_FIELD(RTC_IO_XTAL_32K_PAD_REG, RTC_IO_DBIAS_XTAL_32K, dbias);
SET_PERI_REG_MASK(RTC_IO_XTAL_32K_PAD_REG, RTC_IO_XPD_XTAL_32K);
}
void rtc_clk_32k_enable(bool enable)
{
if (enable) {
rtc_clk_32k_enable_internal(XTAL_32K_DAC_VAL, XTAL_32K_DRES_VAL, XTAL_32K_DBIAS_VAL);
} else {
CLEAR_PERI_REG_MASK(RTC_IO_XTAL_32K_PAD_REG, RTC_IO_XPD_XTAL_32K);
}
}
void rtc_clk_32k_bootstrap()
{
CLEAR_PERI_REG_MASK(RTC_IO_XTAL_32K_PAD_REG, RTC_IO_XPD_XTAL_32K);
SET_PERI_REG_MASK(RTC_IO_XTAL_32K_PAD_REG, RTC_IO_X32P_RUE | RTC_IO_X32N_RDE);
ets_delay_us(XTAL_32K_BOOTSTRAP_TIME_US);
rtc_clk_32k_enable_internal(XTAL_32K_BOOTSTRAP_DAC_VAL,
XTAL_32K_BOOTSTRAP_DRES_VAL, XTAL_32K_BOOTSTRAP_DBIAS_VAL);
}
bool rtc_clk_32k_enabled()
{
return GET_PERI_REG_MASK(RTC_IO_XTAL_32K_PAD_REG, RTC_IO_XPD_XTAL_32K) != 0;
}
void rtc_clk_8m_enable(bool clk_8m_en, bool d256_en)
{
if (clk_8m_en) {
CLEAR_PERI_REG_MASK(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_ENB_CK8M);
/* no need to wait once enabled by software */
REG_SET_FIELD(RTC_CNTL_TIMER1_REG, RTC_CNTL_CK8M_WAIT, 1);
if (d256_en) {
CLEAR_PERI_REG_MASK(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_ENB_CK8M_DIV);
} else {
SET_PERI_REG_MASK(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_ENB_CK8M_DIV);
}
ets_delay_us(DELAY_8M_ENABLE);
} else {
SET_PERI_REG_MASK(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_ENB_CK8M);
REG_SET_FIELD(RTC_CNTL_TIMER1_REG, RTC_CNTL_CK8M_WAIT, RTC_CNTL_CK8M_WAIT_DEFAULT);
}
}
bool rtc_clk_8m_enabled()
{
return GET_PERI_REG_MASK(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_ENB_CK8M) == 0;
}
bool rtc_clk_8md256_enabled()
{
return GET_PERI_REG_MASK(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_ENB_CK8M_DIV) == 0;
}
void rtc_clk_apll_enable(bool enable, uint32_t sdm0, uint32_t sdm1, uint32_t sdm2, uint32_t o_div)
{
REG_SET_FIELD(RTC_CNTL_ANA_CONF_REG, RTC_CNTL_PLLA_FORCE_PD, enable ? 0 : 1);
REG_SET_FIELD(RTC_CNTL_ANA_CONF_REG, RTC_CNTL_PLLA_FORCE_PU, enable ? 1 : 0);
REG_SET_FIELD(RTC_CNTL_OPTIONS0_REG, RTC_CNTL_BIAS_I2C_FORCE_PD, enable ? 0 : 1);
if (!enable &&
REG_GET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_SOC_CLK_SEL) != RTC_CNTL_SOC_CLK_SEL_PLL) {
SET_PERI_REG_MASK(RTC_CNTL_OPTIONS0_REG, RTC_CNTL_BIAS_I2C_FORCE_PD);
}
if (enable) {
uint8_t sdm_stop_val_2 = APLL_SDM_STOP_VAL_2_REV1;
uint32_t is_rev0 = (GET_PERI_REG_BITS2(EFUSE_BLK0_RDATA3_REG, 1, 15) == 0);
if (is_rev0) {
sdm0 = 0;
sdm1 = 0;
sdm_stop_val_2 = APLL_SDM_STOP_VAL_2_REV0;
}
I2C_WRITEREG_MASK_RTC(I2C_APLL, I2C_APLL_DSDM2, sdm2);
I2C_WRITEREG_MASK_RTC(I2C_APLL, I2C_APLL_DSDM0, sdm0);
I2C_WRITEREG_MASK_RTC(I2C_APLL, I2C_APLL_DSDM1, sdm1);
I2C_WRITEREG_RTC(I2C_APLL, I2C_APLL_SDM_STOP, APLL_SDM_STOP_VAL_1);
I2C_WRITEREG_RTC(I2C_APLL, I2C_APLL_SDM_STOP, sdm_stop_val_2);
I2C_WRITEREG_MASK_RTC(I2C_APLL, I2C_APLL_OR_OUTPUT_DIV, o_div);
/* calibration */
I2C_WRITEREG_RTC(I2C_APLL, I2C_APLL_IR_CAL_DELAY, APLL_CAL_DELAY_1);
I2C_WRITEREG_RTC(I2C_APLL, I2C_APLL_IR_CAL_DELAY, APLL_CAL_DELAY_2);
I2C_WRITEREG_RTC(I2C_APLL, I2C_APLL_IR_CAL_DELAY, APLL_CAL_DELAY_3);
/* wait for calibration end */
while (!(I2C_READREG_MASK_RTC(I2C_APLL, I2C_APLL_OR_CAL_END))) {
/* use ets_delay_us so the RTC bus doesn't get flooded */
ets_delay_us(1);
}
}
}
void rtc_clk_slow_freq_set(rtc_slow_freq_t slow_freq)
{
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_ANA_CLK_RTC_SEL, slow_freq);
ets_delay_us(DELAY_SLOW_CLK_SWITCH);
}
rtc_slow_freq_t rtc_clk_slow_freq_get()
{
return REG_GET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_ANA_CLK_RTC_SEL);
}
uint32_t rtc_clk_slow_freq_get_hz()
{
switch(rtc_clk_slow_freq_get()) {
case RTC_SLOW_FREQ_RTC: return RTC_SLOW_CLK_FREQ_150K;
case RTC_SLOW_FREQ_32K_XTAL: return RTC_SLOW_CLK_FREQ_32K;
case RTC_SLOW_FREQ_8MD256: return RTC_SLOW_CLK_FREQ_8MD256;
}
return 0;
}
void rtc_clk_fast_freq_set(rtc_fast_freq_t fast_freq)
{
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_FAST_CLK_RTC_SEL, fast_freq);
ets_delay_us(DELAY_FAST_CLK_SWITCH);
}
rtc_fast_freq_t rtc_clk_fast_freq_get()
{
return REG_GET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_FAST_CLK_RTC_SEL);
}
void rtc_clk_bbpll_set(rtc_xtal_freq_t xtal_freq, rtc_cpu_freq_t cpu_freq)
{
uint8_t div_ref;
uint8_t div7_0;
uint8_t div10_8;
uint8_t lref;
uint8_t dcur;
uint8_t bw;
if (cpu_freq != RTC_CPU_FREQ_240M) {
/* Configure 320M PLL */
switch (xtal_freq) {
case RTC_XTAL_FREQ_40M:
div_ref = 0;
div7_0 = 32;
div10_8 = 0;
lref = 0;
dcur = 6;
bw = 3;
break;
case RTC_XTAL_FREQ_26M:
div_ref = 12;
div7_0 = 224;
div10_8 = 4;
lref = 1;
dcur = 0;
bw = 1;
break;
case RTC_XTAL_FREQ_24M:
div_ref = 11;
div7_0 = 224;
div10_8 = 4;
lref = 1;
dcur = 0;
bw = 1;
break;
default:
div_ref = 12;
div7_0 = 224;
div10_8 = 4;
lref = 0;
dcur = 0;
bw = 0;
break;
}
I2C_WRITEREG_RTC(I2C_BBPLL, I2C_BBPLL_ENDIV5, BBPLL_ENDIV5_VAL_320M);
I2C_WRITEREG_RTC(I2C_BBPLL, I2C_BBPLL_BBADC_DSMP, BBPLL_BBADC_DSMP_VAL_320M);
} else {
/* Raise the voltage */
REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, RTC_CNTL_DBIAS_1V25);
ets_delay_us(DELAY_PLL_DBIAS_RAISE);
/* Configure 480M PLL */
switch (xtal_freq) {
case RTC_XTAL_FREQ_40M:
div_ref = 0;
div7_0 = 28;
div10_8 = 0;
lref = 0;
dcur = 6;
bw = 3;
break;
case RTC_XTAL_FREQ_26M:
div_ref = 12;
div7_0 = 144;
div10_8 = 4;
lref = 1;
dcur = 0;
bw = 1;
break;
case RTC_XTAL_FREQ_24M:
div_ref = 11;
div7_0 = 144;
div10_8 = 4;
lref = 1;
dcur = 0;
bw = 1;
break;
default:
div_ref = 12;
div7_0 = 224;
div10_8 = 4;
lref = 0;
dcur = 0;
bw = 0;
break;
}
I2C_WRITEREG_RTC(I2C_BBPLL, I2C_BBPLL_ENDIV5, BBPLL_ENDIV5_VAL_480M);
I2C_WRITEREG_RTC(I2C_BBPLL, I2C_BBPLL_BBADC_DSMP, BBPLL_BBADC_DSMP_VAL_480M);
}
uint8_t i2c_bbpll_lref = (lref << 7) | (div10_8 << 4) | (div_ref);
uint8_t i2c_bbpll_div_7_0 = div7_0;
uint8_t i2c_bbpll_dcur = (bw << 6) | dcur;
I2C_WRITEREG_RTC(I2C_BBPLL, I2C_BBPLL_OC_LREF, i2c_bbpll_lref);
I2C_WRITEREG_RTC(I2C_BBPLL, I2C_BBPLL_OC_DIV_7_0, i2c_bbpll_div_7_0);
I2C_WRITEREG_RTC(I2C_BBPLL, I2C_BBPLL_OC_DCUR, i2c_bbpll_dcur);
uint32_t delay_pll_en = (rtc_clk_slow_freq_get() == RTC_SLOW_FREQ_RTC) ?
DELAY_PLL_ENABLE_WITH_150K : DELAY_PLL_ENABLE_WITH_32K;
ets_delay_us(delay_pll_en);
}
void rtc_clk_cpu_freq_set(rtc_cpu_freq_t cpu_freq)
{
rtc_xtal_freq_t xtal_freq = rtc_clk_xtal_freq_get();
/* Switch CPU to XTAL frequency first */
REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, RTC_CNTL_DBIAS_1V10);
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_SOC_CLK_SEL, RTC_CNTL_SOC_CLK_SEL_XTL);
REG_SET_FIELD(APB_CTRL_SYSCLK_CONF_REG, APB_CTRL_PRE_DIV_CNT, 0);
ets_update_cpu_frequency(xtal_freq);
/* Frequency switch is synchronized to SLOW_CLK cycle. Wait until the switch
* is complete before disabling the PLL.
*/
rtc_clk_wait_for_slow_cycle();
DPORT_REG_SET_FIELD(DPORT_CPU_PER_CONF_REG, DPORT_CPUPERIOD_SEL, 0);
SET_PERI_REG_MASK(RTC_CNTL_OPTIONS0_REG,
RTC_CNTL_BB_I2C_FORCE_PD | RTC_CNTL_BBPLL_FORCE_PD |
RTC_CNTL_BBPLL_I2C_FORCE_PD);
rtc_clk_apb_freq_update(xtal_freq * MHZ);
/* is APLL under force power down? */
uint32_t apll_fpd = REG_GET_FIELD(RTC_CNTL_ANA_CONF_REG, RTC_CNTL_PLLA_FORCE_PD);
if (apll_fpd) {
/* then also power down the internal I2C bus */
SET_PERI_REG_MASK(RTC_CNTL_OPTIONS0_REG, RTC_CNTL_BIAS_I2C_FORCE_PD);
}
/* now switch to the desired frequency */
if (cpu_freq == RTC_CPU_FREQ_XTAL) {
/* already at XTAL, nothing to do */
} else if (cpu_freq == RTC_CPU_FREQ_2M) {
/* set up divider to produce 2MHz from XTAL */
REG_SET_FIELD(APB_CTRL_SYSCLK_CONF_REG, APB_CTRL_PRE_DIV_CNT, (xtal_freq / 2) - 1);
ets_update_cpu_frequency(2);
rtc_clk_apb_freq_update(2 * MHZ);
/* lower the voltage */
REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, RTC_CNTL_DBIAS_1V00);
} else {
/* use PLL as clock source */
CLEAR_PERI_REG_MASK(RTC_CNTL_OPTIONS0_REG,
RTC_CNTL_BIAS_I2C_FORCE_PD | RTC_CNTL_BB_I2C_FORCE_PD |
RTC_CNTL_BBPLL_FORCE_PD | RTC_CNTL_BBPLL_I2C_FORCE_PD);
rtc_clk_bbpll_set(xtal_freq, cpu_freq);
if (cpu_freq == RTC_CPU_FREQ_80M) {
DPORT_REG_SET_FIELD(DPORT_CPU_PER_CONF_REG, DPORT_CPUPERIOD_SEL, 0);
ets_update_cpu_frequency(80);
} else if (cpu_freq == RTC_CPU_FREQ_160M) {
DPORT_REG_SET_FIELD(DPORT_CPU_PER_CONF_REG, DPORT_CPUPERIOD_SEL, 1);
ets_update_cpu_frequency(160);
} else if (cpu_freq == RTC_CPU_FREQ_240M) {
DPORT_REG_SET_FIELD(DPORT_CPU_PER_CONF_REG, DPORT_CPUPERIOD_SEL, 2);
ets_update_cpu_frequency(240);
}
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_SOC_CLK_SEL, RTC_CNTL_SOC_CLK_SEL_PLL);
rtc_clk_wait_for_slow_cycle();
rtc_clk_apb_freq_update(80 * MHZ);
}
}
rtc_cpu_freq_t rtc_clk_cpu_freq_get()
{
uint32_t soc_clk_sel = REG_GET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_SOC_CLK_SEL);
switch (soc_clk_sel) {
case RTC_CNTL_SOC_CLK_SEL_XTL: {
uint32_t pre_div = REG_GET_FIELD(APB_CTRL_SYSCLK_CONF_REG, APB_CTRL_PRE_DIV_CNT);
if (pre_div == 0) {
return RTC_CPU_FREQ_XTAL;
} else if (pre_div == rtc_clk_xtal_freq_get() / 2 - 1) {
return RTC_CPU_FREQ_2M;
} else {
assert(false && "unsupported frequency");
}
break;
}
case RTC_CNTL_SOC_CLK_SEL_PLL: {
uint32_t cpuperiod_sel = DPORT_REG_GET_FIELD(DPORT_CPU_PER_CONF_REG, DPORT_CPUPERIOD_SEL);
if (cpuperiod_sel == 0) {
return RTC_CPU_FREQ_80M;
} else if (cpuperiod_sel == 1) {
return RTC_CPU_FREQ_160M;
} else if (cpuperiod_sel == 2) {
return RTC_CPU_FREQ_240M;
} else {
assert(false && "unsupported frequency");
}
break;
}
case RTC_CNTL_SOC_CLK_SEL_APLL:
case RTC_CNTL_SOC_CLK_SEL_8M:
default:
assert(false && "unsupported frequency");
}
return RTC_CNTL_SOC_CLK_SEL_XTL;
}
uint32_t rtc_clk_cpu_freq_value(rtc_cpu_freq_t cpu_freq)
{
switch (cpu_freq) {
case RTC_CPU_FREQ_XTAL:
return ((uint32_t) rtc_clk_xtal_freq_get()) * MHZ;
case RTC_CPU_FREQ_2M:
return 2 * MHZ;
case RTC_CPU_FREQ_80M:
return 80 * MHZ;
case RTC_CPU_FREQ_160M:
return 160 * MHZ;
case RTC_CPU_FREQ_240M:
return 240 * MHZ;
default:
assert(false && "invalid rtc_cpu_freq_t value");
return 0;
}
}
/* Values of RTC_XTAL_FREQ_REG and RTC_APB_FREQ_REG are stored as two copies in
* lower and upper 16-bit halves. These are the routines to work with such a
* representation.
*/
static bool clk_val_is_valid(uint32_t val) {
return (val & 0xffff) == ((val >> 16) & 0xffff) &&
val != 0 &&
val != UINT32_MAX;
}
static uint32_t reg_val_to_clk_val(uint32_t val) {
return val & UINT16_MAX;
}
static uint32_t clk_val_to_reg_val(uint32_t val) {
return (val & UINT16_MAX) | ((val & UINT16_MAX) << 16);
}
rtc_xtal_freq_t rtc_clk_xtal_freq_get()
{
/* We may have already written XTAL value into RTC_XTAL_FREQ_REG */
uint32_t xtal_freq_reg = READ_PERI_REG(RTC_XTAL_FREQ_REG);
if (!clk_val_is_valid(xtal_freq_reg)) {
SOC_LOGW(TAG, "invalid RTC_XTAL_FREQ_REG value: 0x%08x", xtal_freq_reg);
return RTC_XTAL_FREQ_AUTO;
}
return reg_val_to_clk_val(xtal_freq_reg);
}
void rtc_clk_xtal_freq_update(rtc_xtal_freq_t xtal_freq)
{
WRITE_PERI_REG(RTC_XTAL_FREQ_REG, clk_val_to_reg_val(xtal_freq));
}
static rtc_xtal_freq_t rtc_clk_xtal_freq_estimate()
{
uint64_t cal_val = rtc_clk_cal_ratio(RTC_CAL_8MD256, XTAL_FREQ_EST_CYCLES);
/* cal_val contains period of 8M/256 clock in XTAL clock cycles
* (shifted by RTC_CLK_CAL_FRACT bits).
* Xtal frequency will be (cal_val * 8M / 256) / 2^19
*/
uint32_t freq_mhz = (cal_val * (RTC_FAST_CLK_FREQ_APPROX / MHZ) / 256 ) >> RTC_CLK_CAL_FRACT;
/* Guess the XTAL type. For now, only 40 and 26MHz are supported.
*/
switch (freq_mhz) {
case 21 ... 31:
return RTC_XTAL_FREQ_26M;
case 32 ... 33:
SOC_LOGW(TAG, "Potentially bogus XTAL frequency: %d MHz, guessing 26 MHz", freq_mhz);
return RTC_XTAL_FREQ_26M;
case 34 ... 35:
SOC_LOGW(TAG, "Potentially bogus XTAL frequency: %d MHz, guessing 40 MHz", freq_mhz);
return RTC_XTAL_FREQ_40M;
case 36 ... 45:
return RTC_XTAL_FREQ_40M;
default:
SOC_LOGW(TAG, "Bogus XTAL frequency: %d MHz", freq_mhz);
return RTC_XTAL_FREQ_AUTO;
}
}
void rtc_clk_apb_freq_update(uint32_t apb_freq)
{
WRITE_PERI_REG(RTC_APB_FREQ_REG, clk_val_to_reg_val(apb_freq >> 12));
}
uint32_t rtc_clk_apb_freq_get()
{
return reg_val_to_clk_val(READ_PERI_REG(RTC_APB_FREQ_REG)) << 12;
}
void rtc_clk_init(rtc_clk_config_t cfg)
{
/* If we get a TG WDT system reset while running at 240MHz,
* DPORT_CPUPERIOD_SEL register will be reset to 0 resulting in 120MHz
* APB and CPU frequencies after reset. This will cause issues with XTAL
* frequency estimation, so we switch to XTAL frequency first.
*
* Ideally we would only do this if RTC_CNTL_SOC_CLK_SEL == PLL and
* PLL is configured for 480M, but it takes less time to switch to 40M and
* run the following code than querying the PLL does.
*/
if (REG_GET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_SOC_CLK_SEL) == RTC_CNTL_SOC_CLK_SEL_PLL) {
rtc_clk_cpu_freq_set(RTC_CPU_FREQ_XTAL);
}
/* Set tuning parameters for 8M and 150k clocks.
* Note: this doesn't attempt to set the clocks to precise frequencies.
* Instead, we calibrate these clocks against XTAL frequency later, when necessary.
* - SCK_DCAP value controls tuning of 150k clock.
* The higher the value of DCAP is, the lower is the frequency.
* - CK8M_DFREQ value controls tuning of 8M clock.
* CLK_8M_DFREQ constant gives the best temperature characteristics.
*/
REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_SCK_DCAP, cfg.slow_clk_dcap);
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_CK8M_DFREQ, cfg.clk_8m_dfreq);
/* Configure 8M clock division */
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_CK8M_DIV_SEL, cfg.clk_8m_div);
/* Enable the internal bus used to configure PLLs */
SET_PERI_REG_BITS(ANA_CONFIG_REG, ANA_CONFIG_M, ANA_CONFIG_M, ANA_CONFIG_S);
CLEAR_PERI_REG_MASK(ANA_CONFIG_REG, I2C_APLL_M | I2C_BBPLL_M);
/* Estimate XTAL frequency if requested */
rtc_xtal_freq_t xtal_freq = cfg.xtal_freq;
if (xtal_freq == RTC_XTAL_FREQ_AUTO) {
if (clk_val_is_valid(READ_PERI_REG(RTC_XTAL_FREQ_REG))) {
/* XTAL frequency has already been set, use existing value */
xtal_freq = rtc_clk_xtal_freq_get();
} else {
/* Not set yet, estimate XTAL frequency based on RTC_FAST_CLK */
xtal_freq = rtc_clk_xtal_freq_estimate();
if (xtal_freq == RTC_XTAL_FREQ_AUTO) {
SOC_LOGW(TAG, "Can't estimate XTAL frequency, assuming 26MHz");
xtal_freq = RTC_XTAL_FREQ_26M;
}
}
}
rtc_clk_xtal_freq_update(xtal_freq);
rtc_clk_apb_freq_update(xtal_freq * MHZ);
/* Set CPU frequency */
rtc_clk_cpu_freq_set(cfg.cpu_freq);
/* Slow & fast clocks setup */
if (cfg.slow_freq == RTC_SLOW_FREQ_32K_XTAL) {
rtc_clk_32k_enable(true);
}
if (cfg.fast_freq == RTC_FAST_FREQ_8M) {
bool need_8md256 = cfg.slow_freq == RTC_SLOW_FREQ_8MD256;
rtc_clk_8m_enable(true, need_8md256);
}
rtc_clk_fast_freq_set(cfg.fast_freq);
rtc_clk_slow_freq_set(cfg.slow_freq);
}
/* Name used in libphy.a:phy_chip_v7.o
* TODO: update the library to use rtc_clk_xtal_freq_get
*/
rtc_xtal_freq_t rtc_get_xtal() __attribute__((alias("rtc_clk_xtal_freq_get")));
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