Merge branch 'bugfix/range_CONFIG_ESP32_RTC_CLK_CAL_CYCLES' into 'master'

soc/clk: Fix range CONFIG_ESP32_RTC_CLK_CAL_CYCLES

See merge request idf/esp-idf!2719

components/esp32/Kconfig

@@ -694,7 +694,8 @@ config ESP32_RTC_CLK_CAL_CYCLES
     int "Number of cycles for RTC_SLOW_CLK calibration"
     default 3000 if ESP32_RTC_CLOCK_SOURCE_EXTERNAL_CRYSTAL
     default 1024 if ESP32_RTC_CLOCK_SOURCE_INTERNAL_RC
-    range 0 125000
+    range 0 27000 if ESP32_RTC_CLOCK_SOURCE_EXTERNAL_CRYSTAL
+    range 0 32766 if ESP32_RTC_CLOCK_SOURCE_INTERNAL_RC
     help
         When the startup code initializes RTC_SLOW_CLK, it can perform
         calibration by comparing the RTC_SLOW_CLK frequency with main XTAL

components/esp32/clk.c

@@ -128,7 +128,9 @@ static void select_rtc_slow_clk(rtc_slow_freq_t slow_clk)
 {
     uint32_t cal_val = 0;
     uint32_t wait = 0;
-    const uint32_t warning_timeout = 3 /* sec */ * 32768 /* Hz */ / (2 * SLOW_CLK_CAL_CYCLES);
+    uint32_t freq_hz = ((slow_clk == RTC_SLOW_FREQ_32K_XTAL) ? 32768 : 150000);
+    uint32_t warning_timeout = 3 /* sec */ * freq_hz /* Hz */ / (SLOW_CLK_CAL_CYCLES + 1);
+    warning_timeout = ((warning_timeout == 0) ? 3 /* sec */ : warning_timeout);
     bool changing_clock_to_150k = false;
     do {
         if (slow_clk == RTC_SLOW_FREQ_32K_XTAL) {
@@ -141,11 +143,14 @@ static void select_rtc_slow_clk(rtc_slow_freq_t slow_clk)
              */
             ESP_EARLY_LOGD(TAG, "waiting for 32k oscillator to start up");
             rtc_clk_32k_enable(true);
-            cal_val = rtc_clk_cal(RTC_CAL_32K_XTAL, SLOW_CLK_CAL_CYCLES);
-            if(cal_val == 0 || cal_val < 15000000L){
-                ESP_EARLY_LOGE(TAG, "RTC: Not found External 32 kHz XTAL. Switching to Internal 150 kHz RC chain");
-                slow_clk = RTC_SLOW_FREQ_RTC;
-                changing_clock_to_150k = true;
+            // When SLOW_CLK_CAL_CYCLES is set to 0, clock calibration will not be performed at startup.
+            if (SLOW_CLK_CAL_CYCLES > 0) {
+                cal_val = rtc_clk_cal(RTC_CAL_32K_XTAL, SLOW_CLK_CAL_CYCLES);
+                if (cal_val == 0 || cal_val < 15000000L) {
+                    ESP_EARLY_LOGE(TAG, "RTC: Not found External 32 kHz XTAL. Switching to Internal 150 kHz RC chain");
+                    slow_clk = RTC_SLOW_FREQ_RTC;
+                    changing_clock_to_150k = true;
+                }
             }
         }
         rtc_clk_slow_freq_set(slow_clk);

components/soc/esp32/rtc_time.c

@@ -17,6 +17,7 @@
 #include "soc/rtc.h"
 #include "soc/rtc_cntl_reg.h"
 #include "soc/timer_group_reg.h"
+#include "assert.h"
 
 #define MHZ (1000000)
 
@@ -35,11 +36,12 @@
 /**
  * @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
+ * @param slowclk_cycles number of slow clock cycles to count. Max value is 32766.
  * @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)
 {
+    assert(slowclk_cycles < 32767);
     /* 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) {
@@ -56,16 +58,21 @@ static uint32_t rtc_clk_cal_internal(rtc_cal_sel_t cal_clk, uint32_t slowclk_cyc
     /* 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);
+    uint32_t us_timer_max = 0xFFFFFFFF;
     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 */
+        us_timer_max = (uint32_t) (TIMG_RTC_CALI_VALUE / rtc_clk_xtal_freq_get());
     } 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 */
+        us_timer_max = (uint32_t) (TIMG_RTC_CALI_VALUE / rtc_clk_xtal_freq_get());
     }
     uint32_t us_time_estimate = (uint32_t) (((uint64_t) slowclk_cycles) * MHZ / expected_freq);
+    // The required amount of slowclk_cycles can produce in a counter TIMG a overflow error. Decrease the slowclk_cycles for fix it.
+    assert(us_time_estimate < us_timer_max);
     /* 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);