Disable RTC WDT on connect for USB-SERIAL-JTAG

When the chip is reset via the USB-SERIAL-JTAG not everything is fully
reset, the RTC domain stays active. Therefore, if the RTC watchdog is
enabled before being put into download mode it will trigger when
flashing, hence resetting the board and interrupting flashing.

Author: MabezDev

espflash/src/connection.rs

@@ -16,7 +16,7 @@ use crate::{
 };
 
 const DEFAULT_CONNECT_ATTEMPTS: usize = 7;
-const USB_SERIAL_JTAG_PID: u16 = 0x1001;
+pub const USB_SERIAL_JTAG_PID: u16 = 0x1001;
 
 #[derive(Debug, Copy, Clone, BinRead)]
 pub struct CommandResponse {

espflash/src/flash_target/esp32.rs

@@ -1,5 +1,5 @@
 use crate::command::{Command, CommandType};
-use crate::connection::Connection;
+use crate::connection::{Connection, USB_SERIAL_JTAG_PID};
 use crate::elf::{FirmwareImage, RomSegment};
 use crate::error::Error;
 use crate::flash_target::FlashTarget;
@@ -31,6 +31,49 @@ impl FlashTarget for Esp32Target {
                 spi_params: self.spi_attach_params,
             })
         })?;
+
+        // TODO remove this when we use the stub, the stub should be taking care of this.
+        // TODO do we also need to disable rtc super wdt?
+        if connection.get_usb_pid()? == USB_SERIAL_JTAG_PID {
+            match self.chip {
+                Chip::Esp32c3 => {
+                    connection.command(Command::WriteReg {
+                        address: 0x600080a8,
+                        value: 0x50D83AA1u32,
+                        mask: None,
+                    })?; // WP disable
+                    connection.command(Command::WriteReg {
+                        address: 0x60008090,
+                        value: 0x0,
+                        mask: None,
+                    })?; // turn off RTC WDG
+                    connection.command(Command::WriteReg {
+                        address: 0x600080a8,
+                        value: 0x0,
+                        mask: None,
+                    })?; // WP enable
+                }
+                Chip::Esp32s3 => {
+                    connection.command(Command::WriteReg {
+                        address: 0x00B0,
+                        value: 0x50D83AA1u32,
+                        mask: None,
+                    })?; // WP disable
+                    connection.command(Command::WriteReg {
+                        address: 0x0098,
+                        value: 0x0,
+                        mask: None,
+                    })?; // turn off RTC WDG
+                    connection.command(Command::WriteReg {
+                        address: 0x00B0,
+                        value: 0x0,
+                        mask: None,
+                    })?; // WP enable
+                }
+                _ => {}
+            }
+        }
+
         Ok(())
     }