Add support for 160MHz rated CPUs

Some ESP32 chips are rated only to 160MHz. This change adds support for them and does not allow frequency to be switched to 240MHz

Author: me-no-dev

cores/esp32/esp32-hal-cpu.c

@@ -23,6 +23,7 @@
 #include "soc/rtc_cntl_reg.h"
 #include "rom/rtc.h"
 #include "soc/apb_ctrl_reg.h"
+#include "soc/efuse_reg.h"
 #include "esp32-hal.h"
 #include "esp32-hal-cpu.h"
 
@@ -150,6 +151,15 @@ bool setCpuFrequencyMhz(uint32_t cpu_freq_mhz){
         }
         return false;
     }
+    //check if cpu supports the frequency
+    if(cpu_freq_mhz == 240){
+        //Check if ESP32 is rated for a CPU frequency of 160MHz only
+        if (REG_GET_BIT(EFUSE_BLK0_RDATA3_REG, EFUSE_RD_CHIP_CPU_FREQ_RATED) &&
+            REG_GET_BIT(EFUSE_BLK0_RDATA3_REG, EFUSE_RD_CHIP_CPU_FREQ_LOW)) {
+            log_e("Can not switch to 240 MHz! Chip CPU frequency rated for 160MHz.");
+            cpu_freq_mhz = 160;
+        }
+    }
     //Get current CPU clock configuration
     rtc_clk_cpu_freq_get_config(&cconf);
     //return if frequency has not changed