Implement new USB Serial JTAG reset strategy (#779)

* Add watchdog reset experiment

* changelog

* Add bitflags dependency and cleanup

* fix register values, ... again

* Add P4

* reviews

* move connection_is_usb_otg to Connection struct and rename it to is_using_usb_otg

* fix ci

* Use latest version of `bitflags`

* Move and improve the `RtcWdtReset` trait

* Introduce `UsbOtg` trait for targets

* Fix some warnings

* Cleanup

---------

Co-authored-by: Jesse Braham <[email protected]>

Author: JurajSadel

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add list-ports command to list available serial ports. (#761)
 - [cargo-espflash]: Add `write-bin` subcommand (#789)
 - Add `--monitor` option to `write-bin`. (#783)
+- Add `watchdog-reset` strategy to `--after` subcommand (#779)
 
 ### Changed
 

Cargo.lock

@@ -264,6 +264,7 @@ pub fn erase_parts(args: ErasePartsArgs, config: &Config) -> Result<()> {
         .or(config.partition_table.as_deref());
 
     let mut flasher = connect(&args.connect_args, config, false, false)?;
+    let chip = flasher.chip();
     let partition_table = match partition_table {
         Some(path) => Some(parse_partition_table(path)?),
         None => None,
@@ -274,7 +275,7 @@ pub fn erase_parts(args: ErasePartsArgs, config: &Config) -> Result<()> {
     erase_partitions(&mut flasher, partition_table, Some(args.erase_parts), None)?;
     flasher
         .connection()
-        .reset_after(!args.connect_args.no_stub)?;
+        .reset_after(!args.connect_args.no_stub, chip)?;
 
     Ok(())
 }

cargo-espflash/src/main.rs

@@ -27,6 +27,7 @@ required-features = ["cli", "serialport"]
 [dependencies]
 addr2line       = { version = "0.24.2", optional = true }
 base64          = "0.22.1"
+bitflags        = "2.9.0"
 bytemuck        = { version = "1.21.0", features = ["derive"] }
 clap            = { version = "4.5.24", features = ["derive", "env", "wrap_help"], optional = true }
 clap_complete   = { version = "4.5.41", optional = true }

espflash/Cargo.toml

@@ -183,6 +183,7 @@ pub fn erase_parts(args: ErasePartsArgs, config: &Config) -> Result<()> {
     }
 
     let mut flasher = connect(&args.connect_args, config, false, false)?;
+    let chip = flasher.chip();
     let partition_table = match args.partition_table {
         Some(path) => Some(parse_partition_table(&path)?),
         None => None,
@@ -193,7 +194,7 @@ pub fn erase_parts(args: ErasePartsArgs, config: &Config) -> Result<()> {
     erase_partitions(&mut flasher, partition_table, Some(args.erase_parts), None)?;
     flasher
         .connection()
-        .reset_after(!args.connect_args.no_stub)?;
+        .reset_after(!args.connect_args.no_stub, chip)?;
 
     info!("Specified partitions successfully erased!");
 

espflash/src/bin/espflash.rs

@@ -723,10 +723,12 @@ pub fn erase_flash(args: EraseFlashArgs, config: &Config) -> Result<()> {
     let mut flasher = connect(&args.connect_args, config, true, true)?;
     info!("Erasing Flash...");
 
+    let chip = flasher.chip();
+
     flasher.erase_flash()?;
     flasher
         .connection()
-        .reset_after(!args.connect_args.no_stub)?;
+        .reset_after(!args.connect_args.no_stub, chip)?;
 
     info!("Flash has been erased!");
 
@@ -747,6 +749,7 @@ pub fn erase_region(args: EraseRegionArgs, config: &Config) -> Result<()> {
     }
 
     let mut flasher = connect(&args.connect_args, config, true, true)?;
+    let chip = flasher.chip();
 
     info!(
         "Erasing region at 0x{:08x} ({} bytes)",
@@ -756,7 +759,7 @@ pub fn erase_region(args: EraseRegionArgs, config: &Config) -> Result<()> {
     flasher.erase_region(args.address, args.size)?;
     flasher
         .connection()
-        .reset_after(!args.connect_args.no_stub)?;
+        .reset_after(!args.connect_args.no_stub, chip)?;
 
     Ok(())
 }

espflash/src/cli/mod.rs

@@ -33,7 +33,10 @@ use self::{
         UsbJtagSerialReset,
     },
 };
-use crate::error::{ConnectionError, Error, ResultExt, RomError, RomErrorKind};
+use crate::{
+    error::{ConnectionError, Error, ResultExt, RomError, RomErrorKind},
+    targets::Chip,
+};
 
 pub(crate) mod command;
 pub(crate) mod reset;
@@ -274,7 +277,7 @@ impl Connection {
     }
 
     // Reset the device taking into account the reset after argument
-    pub fn reset_after(&mut self, is_stub: bool) -> Result<(), Error> {
+    pub fn reset_after(&mut self, is_stub: bool, chip: Chip) -> Result<(), Error> {
         let pid = self.usb_pid();
 
         match self.after_operation {
@@ -289,12 +292,62 @@ impl Connection {
                 info!("Staying in flasher stub");
                 Ok(())
             }
+            ResetAfterOperation::WatchdogReset => {
+                info!("Resetting device with watchdog");
+
+                match chip {
+                    Chip::Esp32c3 => {
+                        if self.is_using_usb_serial_jtag() {
+                            chip.into_rtc_wdt_reset()?.rtc_wdt_reset(self)?;
+                        }
+                    }
+                    Chip::Esp32p4 => {
+                        // Check if the connection is USB OTG
+                        if chip.into_usb_otg()?.is_using_usb_otg(self)? {
+                            chip.into_rtc_wdt_reset()?.rtc_wdt_reset(self)?;
+                        }
+                    }
+                    Chip::Esp32s2 => {
+                        // Check if the connection is USB OTG
+                        if chip.into_usb_otg()?.is_using_usb_otg(self)? {
+                            let target = chip.into_rtc_wdt_reset()?;
+
+                            // Check the strapping register to see if we can perform RTC WDT
+                            // reset
+                            if target.can_rtc_wdt_reset(self)? {
+                                target.rtc_wdt_reset(self)?;
+                            }
+                        }
+                    }
+                    Chip::Esp32s3 => {
+                        if self.is_using_usb_serial_jtag()
+                            || chip.into_usb_otg()?.is_using_usb_otg(self)?
+                        {
+                            let target = chip.into_rtc_wdt_reset()?;
+
+                            // Check the strapping register to see if we can perform RTC WDT
+                            // reset
+                            if target.can_rtc_wdt_reset(self)? {
+                                target.rtc_wdt_reset(self)?;
+                            }
+                        }
+                    }
+                    _ => {
+                        return Err(Error::UnsupportedFeature {
+                            chip,
+                            feature: "watchdog reset".into(),
+                        })
+                    }
+                }
+
+                Ok(())
+            }
         }
     }
 
     // Reset the device to flash mode
     pub fn reset_to_flash(&mut self, extra_delay: bool) -> Result<(), Error> {
-        if self.port_info.pid == USB_SERIAL_JTAG_PID {
+        if self.is_using_usb_serial_jtag() {
             UsbJtagSerialReset.reset(&mut self.serial)
         } else {
             #[cfg(unix)]

espflash/src/connection/mod.rs

@@ -362,4 +362,6 @@ pub enum ResetAfterOperation {
     NoReset,
     /// Leaves the chip in the stub bootloader, no reset is performed.
     NoResetNoStub,
+    /// Hard-resets the chip by triggering an internal watchdog reset.
+    WatchdogReset,
 }

espflash/src/connection/reset.rs

@@ -17,6 +17,7 @@ use serde::{Deserialize, Serialize};
 #[cfg(feature = "serialport")]
 use serialport::UsbPortInfo;
 use strum::{Display, EnumIter, IntoEnumIterator, VariantNames};
+#[cfg(feature = "serialport")]
 use xmas_elf::ElfFile;
 
 #[cfg(feature = "serialport")]
@@ -31,7 +32,7 @@ use crate::{
         Connection,
         Port,
     },
-    error::{ConnectionError, ResultExt},
+    error::{ConnectionError, ElfError, ResultExt as _},
     flasher::stubs::{
         FlashStub,
         CHIP_DETECT_MAGIC_REG_ADDR,
@@ -41,8 +42,8 @@ use crate::{
     image_format::{ram_segments, rom_segments, Segment},
 };
 use crate::{
-    error::{ElfError, Error},
     targets::{Chip, XtalFrequency},
+    Error,
 };
 
 #[cfg(feature = "serialport")]

espflash/src/flasher/mod.rs

@@ -114,3 +114,22 @@ impl Target for Esp32c3 {
         ]
     }
 }
+
+#[cfg(feature = "serialport")]
+impl super::RtcWdtReset for Esp32c3 {
+    fn wdt_wprotect(&self) -> u32 {
+        0x6000_80A8
+    }
+
+    fn wdt_config0(&self) -> u32 {
+        0x6000_8090
+    }
+
+    fn wdt_config1(&self) -> u32 {
+        0x6000_8094
+    }
+
+    fn can_rtc_wdt_reset(&self, _connection: &mut Connection) -> Result<bool, Error> {
+        Ok(true)
+    }
+}