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soc/rtc: add fast paths for switching between PLL and XTAL

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This commit is contained in:
Ivan Grokhotkov 2017-08-21 22:34:42 +08:00
parent 37e9bc715c
commit a242ae6d0b
2 changed files with 92 additions and 2 deletions
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19
components/soc/esp32/include/soc/rtc.h
View File

@ -276,6 +276,25 @@ rtc_fast_freq_t rtc_clk_fast_freq_get();
*/
void rtc_clk_cpu_freq_set(rtc_cpu_freq_t cpu_freq);
/**
* @brief Switch CPU frequency
*
* This is a faster version of rtc_clk_cpu_freq_set, which can handle some of
* the frequency switch paths (XTAL -> PLL, PLL -> XTAL).
* When switching from PLL to XTAL, PLL is not disabled (unlike rtc_clk_cpu_freq_set).
* When switching back from XTAL to PLL, only the same PLL can be used.
* Therefore it is not possible to switch 240 -> XTAL -> (80 or 160) using this
* function.
*
* For unsupported cases, this function falls back to rtc_clk_cpu_freq_set.
*
* Unlike rtc_clk_cpu_freq_set, this function relies on static data, so it is
* less safe to use it e.g. from a panic handler (when memory might be corrupted).
*
* @param cpu_freq new CPU frequency
*/
void rtc_clk_cpu_freq_set_fast(rtc_cpu_freq_t cpu_freq);
/**
* @brief Get the currently selected CPU frequency
*

75
components/soc/esp32/rtc_clk.c
View File

@ -72,9 +72,9 @@ static const char* TAG = "rtc_clk";
* All values are in microseconds.
* TODO: some of these are excessive, and should be reduced.
*/
#define DELAY_CPU_FREQ_SWITCH_TO_XTAL_WITH_150K 80
#define DELAY_CPU_FREQ_SWITCH_TO_XTAL_WITH_150K 20
#define DELAY_CPU_FREQ_SWITCH_TO_XTAL_WITH_32K 160
#define DELAY_CPU_FREQ_SWITCH_TO_PLL 10
#define DELAY_CPU_FREQ_SWITCH_TO_PLL 20
#define DELAY_PLL_DBIAS_RAISE 3
#define DELAY_PLL_ENABLE_WITH_150K 80
#define DELAY_PLL_ENABLE_WITH_32K 160
@ -87,6 +87,8 @@ static const char* TAG = "rtc_clk";
*/
#define XTAL_FREQ_EST_CYCLES 10
static rtc_cpu_freq_t s_cur_freq = RTC_CPU_FREQ_XTAL;
static int s_pll_freq = 0;
static void rtc_clk_32k_enable_internal(int dac, int dres, int dbias)
{
@ -323,6 +325,70 @@ void rtc_clk_bbpll_set(rtc_xtal_freq_t xtal_freq, rtc_cpu_freq_t cpu_freq)
ets_delay_us(delay_pll_en);
}
/**
* Switch to XTAL frequency. Does not disable the PLL.
*/
static void rtc_clk_cpu_freq_to_xtal()
{
rtc_xtal_freq_t xtal_freq = rtc_clk_xtal_freq_get();
ets_update_cpu_frequency(xtal_freq);
REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, RTC_CNTL_DBIAS_1V10);
REG_SET_FIELD(APB_CTRL_SYSCLK_CONF_REG, APB_CTRL_PRE_DIV_CNT, 0);
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_SOC_CLK_SEL, RTC_CNTL_SOC_CLK_SEL_XTL);
DPORT_REG_WRITE(DPORT_CPU_PER_CONF_REG, 0); // clear DPORT_CPUPERIOD_SEL
rtc_clk_apb_freq_update(xtal_freq * MHZ);
s_cur_freq = RTC_CPU_FREQ_XTAL;
}
/**
* Switch to one of PLL-based frequencies. Current frequency can be XTAL or PLL.
* PLL must already be enabled.
* If switching between frequencies derived from different PLLs (320M and 480M),
* fall back to rtc_clk_cpu_freq_set.
* @param cpu_freq new CPU frequency
*/
static void rtc_clk_cpu_freq_to_pll(rtc_cpu_freq_t cpu_freq)
{
int freq = 0;
if ((cpu_freq == RTC_CPU_FREQ_240M && s_pll_freq == 320) ||
(cpu_freq != RTC_CPU_FREQ_240M && s_pll_freq == 240)) {
/* need to switch PLLs, fall back to full implementation */
rtc_clk_cpu_freq_set(cpu_freq);
return;
}
if (cpu_freq == RTC_CPU_FREQ_80M) {
DPORT_REG_WRITE(DPORT_CPU_PER_CONF_REG, 0);
freq = 80;
} else if (cpu_freq == RTC_CPU_FREQ_160M) {
DPORT_REG_WRITE(DPORT_CPU_PER_CONF_REG, 1);
freq = 160;
} else if (cpu_freq == RTC_CPU_FREQ_240M) {
REG_SET_FIELD(RTC_CNTL_REG, RTC_CNTL_DIG_DBIAS_WAK, RTC_CNTL_DBIAS_1V25);
DPORT_REG_WRITE(DPORT_CPU_PER_CONF_REG, 2);
freq = 240;
}
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_SOC_CLK_SEL, RTC_CNTL_SOC_CLK_SEL_PLL);
rtc_clk_apb_freq_update(80 * MHZ);
ets_update_cpu_frequency(freq);
s_cur_freq = cpu_freq;
}
void rtc_clk_cpu_freq_set_fast(rtc_cpu_freq_t cpu_freq)
{
if (cpu_freq == s_cur_freq) {
return;
} else if (cpu_freq == RTC_CPU_FREQ_2M || s_cur_freq == RTC_CPU_FREQ_2M) {
/* fall back to full implementation if switch to/from 2M is needed */
rtc_clk_cpu_freq_set(cpu_freq);
} else if (cpu_freq == RTC_CPU_FREQ_XTAL) {
rtc_clk_cpu_freq_to_xtal();
} else if (cpu_freq > RTC_CPU_FREQ_XTAL) {
rtc_clk_cpu_freq_to_pll(cpu_freq);
}
}
void rtc_clk_cpu_freq_set(rtc_cpu_freq_t cpu_freq)
{
rtc_xtal_freq_t xtal_freq = rtc_clk_xtal_freq_get();
@ -338,6 +404,7 @@ void rtc_clk_cpu_freq_set(rtc_cpu_freq_t cpu_freq)
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);
s_pll_freq = 0;
rtc_clk_apb_freq_update(xtal_freq * MHZ);
/* is APLL under force power down? */
@ -365,17 +432,21 @@ void rtc_clk_cpu_freq_set(rtc_cpu_freq_t 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);
s_pll_freq = 320;
} 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);
s_pll_freq = 320;
} 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);
s_pll_freq = 480;
}
REG_SET_FIELD(RTC_CNTL_CLK_CONF_REG, RTC_CNTL_SOC_CLK_SEL, RTC_CNTL_SOC_CLK_SEL_PLL);
ets_delay_us(DELAY_CPU_FREQ_SWITCH_TO_PLL);
rtc_clk_apb_freq_update(80 * MHZ);
}
s_cur_freq = cpu_freq;
}
rtc_cpu_freq_t rtc_clk_cpu_freq_get()