Add auto-detection feature to esp-println (#1658)

* Add auto-detection feature to esp-println

* CHANGELOG.md

* Minor README change

* Build `esp-println` in CI

.github/workflows/ci.yml

@@ -152,6 +152,53 @@ jobs:
       - name: Build esp-riscv-rt (riscv32imac, all features)
         run: cd esp-riscv-rt/ && cargo build --target=riscv32imac-unknown-none-elf --features=ci
 
+  esp-println:
+    name: esp-println (${{ matrix.device.soc }})
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        device: [
+            # RISC-V devices:
+            { soc: "esp32c2", target: "riscv32imc-unknown-none-elf" },
+            { soc: "esp32c3", target: "riscv32imc-unknown-none-elf" },
+            { soc: "esp32c6", target: "riscv32imac-unknown-none-elf" },
+            { soc: "esp32h2", target: "riscv32imac-unknown-none-elf" },
+            # Xtensa devices:
+            { soc: "esp32", target: "xtensa-esp32-none-elf" },
+            { soc: "esp32s2", target: "xtensa-esp32s2-none-elf" },
+            { soc: "esp32s3", target: "xtensa-esp32s3-none-elf" },
+          ]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      # Install the Rust toolchain for RISC-V devices:
+      - if: ${{ !contains(fromJson('["esp32", "esp32s2", "esp32s3"]'), matrix.device.soc) }}
+        uses: dtolnay/rust-toolchain@v1
+        with:
+          target: riscv32imc-unknown-none-elf,riscv32imac-unknown-none-elf
+          toolchain: stable
+          components: rust-src
+      # Install the Rust toolchain for Xtensa devices:
+      - if: contains(fromJson('["esp32", "esp32s2", "esp32s3"]'), matrix.device.soc)
+        uses: esp-rs/xtensa-toolchain@v1.5
+        with:
+          buildtargets: ${{ matrix.device.soc }}
+          default: true
+          ldproxy: false
+
+      - uses: Swatinem/rust-cache@v2
+
+      # Make sure we're able to build with the default features and most common features enabled
+      - name: Build (no features)
+        run: |
+          cargo xtask build-package \
+            --features=${{ matrix.device.soc }},log \
+            --target=${{ matrix.device.target }} \
+            esp-println
+        
   extras:
     runs-on: ubuntu-latest
 

esp-println/.cargo/config.toml

@@ -0,0 +1,2 @@
+[unstable]
+build-std = ["alloc", "core"]

esp-println/CHANGELOG.md

@@ -0,0 +1,43 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Added
+
+- Add `auto` feature to auto-detect Serial-JTAG/UART communication (#1658)
+
+### Fixed
+
+### Changed
+
+- `auto` is the default communication method (#1658)
+
+### Removed
+
+## [0.9.1] - 2024-03-11
+
+### Changed
+
+- Un-pinned the defmt package's version number
+
+## [0.9.0] - 2024-02-07
+
+### Added
+
+- Add support for ESP32-P4
+
+### Removed
+
+- Remove ESP 8266 support
+
+## [0.8.0] - 2023-12-21
+
+### Removed
+
+- Remove RTT and defmt-raw support
+

esp-println/Cargo.toml

@@ -22,7 +22,7 @@ portable-atomic  = { version = "1.6.0",  optional = true, default-features = fal
 esp-build = { version = "0.1.0", path = "../esp-build" }
 
 [features]
-default = ["dep:critical-section", "colors", "uart"]
+default = ["dep:critical-section", "colors", "auto"]
 log     = ["dep:log"]
 
 # You must enable exactly 1 of the below features to support the correct chip:
@@ -36,10 +36,13 @@ esp32s2 = []
 esp32s3 = []
 
 # You must enable exactly 1 of the below features to enable to intended
-# communication method (note that "uart" is enabled by default):
+# communication method (note that "auto" is enabled by default):
 jtag-serial = ["dep:portable-atomic"] # C3, C6, H2, P4, and S3 only!
-no-op       = []
 uart        = []
+auto        = ["dep:portable-atomic"]
+
+# Don't print anything
+no-op       = []
 
 # Enables a `defmt` backend usable with espflash. We force rzcobs encoding to simplify implementation
 defmt-espflash = ["dep:defmt", "defmt?/encoding-rzcobs"]

esp-println/README.md

@@ -39,22 +39,23 @@ You can now `println!("Hello world")` as usual.
   `esp32c3`, `esp32c6`, `esp32h2`, `esp32s2`, and `esp32s3`.
   - One of these features must be enabled.
   - Only one of these features can be enabled at a time.
-- There is one feature for each supported communication method: `uart`, `jtag-serial` and `no-op`.
+- There is one feature for each supported communication method: `uart`, `jtag-serial` and `auto`.
   - Only one of these features can be enabled at a time.
+- `no-op`: Don't print anything.
 - `log`: Enables logging using [`log` crate].
-- `colors` enable colored logging.
+- `colors`: Enable colored logging.
   - Only effective when using the `log` feature.
-- `critical-section` enables critical sections.
+- `critical-section`: Enables critical sections.
 - `defmt-espflash`: This is intended to be used with [`espflash`], see `-L/--log-format` argument
   of `flash` or `monitor` subcommands of `espflash` and `cargo-espflash`. Uses [rzCOBS] encoding
   and adds framing.
 
 ## Default Features
 
-By default, we use the `uart`, `critial-section` and `colors` features.
-Which means that it will print to the UART, use critical sections and output
+By default, we use the `auto`, `critial-section` and `colors` features.
+Which means that it will auto-detect if it needs to print to the UART or JTAG-Serial, use critical sections and output
 messages will be colored.
-If we want to use a communication method that is not `uart`, the default
+If we want to use a communication method that is not `auto`, the default
 one, we need to [disable the default features].
 
 ## Logging

esp-println/build.rs

@@ -7,7 +7,7 @@ fn main() {
     );
 
     // Ensure that only a single communication method is specified
-    assert_unique_used_features!("jtag-serial", "uart");
+    assert_unique_used_features!("jtag-serial", "uart", "auto");
 
     // Ensure that, if the `jtag-serial` communication method feature is enabled,
     // either the `esp32c3`, `esp32c6`, `esp32h2`, or `esp32s3` chip feature is

esp-println/src/lib.rs

@@ -68,26 +68,94 @@ macro_rules! dbg {
     };
 }
 
+#[cfg(any(feature = "jtag-serial", feature = "auto"))]
+pub struct PrinterSerialJtag;
+
+#[cfg(any(feature = "uart", feature = "auto"))]
+pub struct PrinterUart;
+
+#[cfg(feature = "jtag-serial")]
+pub type PrinterImpl = PrinterSerialJtag;
+
+#[cfg(feature = "uart")]
+pub type PrinterImpl = PrinterUart;
+
 pub struct Printer;
 
 impl core::fmt::Write for Printer {
     fn write_str(&mut self, s: &str) -> core::fmt::Result {
-        Printer.write_bytes(s.as_bytes());
+        Printer::write_bytes(s.as_bytes());
         Ok(())
     }
 }
 
 impl Printer {
-    pub fn write_bytes(&mut self, bytes: &[u8]) {
+    #[cfg(not(feature = "auto"))]
+    pub fn write_bytes(bytes: &[u8]) {
         with(|| {
-            self.write_bytes_assume_cs(bytes);
-            self.flush();
+            PrinterImpl::write_bytes_assume_cs(bytes);
+            PrinterImpl::flush();
+        })
+    }
+
+    #[cfg(feature = "auto")]
+    pub fn write_bytes(bytes: &[u8]) {
+        #[cfg(any(
+            feature = "esp32c3",
+            feature = "esp32c6",
+            feature = "esp32h2",
+            feature = "esp32s3"
+        ))]
+        {
+            // Decide if serial-jtag is used by checking SOF interrupt flag.
+            // SOF packet is sent by the HOST every 1ms on a full speed bus.
+            // Between two consecutive ticks, there will be at least 1ms (selectable tick
+            // rate range is 1 - 1000Hz).
+            // We don't reset the flag - if it was ever connected we assume serial-jtag is
+            // used
+
+            #[cfg(feature = "esp32c3")]
+            const USB_DEVICE_INT_RAW: *const u32 = 0x60043008 as *const u32;
+            #[cfg(feature = "esp32c6")]
+            const USB_DEVICE_INT_RAW: *const u32 = 0x6000f008 as *const u32;
+            #[cfg(feature = "esp32h2")]
+            const USB_DEVICE_INT_RAW: *const u32 = 0x6000f008 as *const u32;
+            #[cfg(feature = "esp32s3")]
+            const USB_DEVICE_INT_RAW: *const u32 = 0x60038000 as *const u32;
+
+            const SOF_INT_MASK: u32 = 0b10;
+
+            let is_serial_jtag =
+                unsafe { (USB_DEVICE_INT_RAW.read_volatile() & SOF_INT_MASK) != 0 };
+
+            if is_serial_jtag {
+                with(|| {
+                    PrinterSerialJtag::write_bytes_assume_cs(bytes);
+                    PrinterSerialJtag::flush();
+                })
+            } else {
+                with(|| {
+                    PrinterUart::write_bytes_assume_cs(bytes);
+                    PrinterUart::flush();
+                })
+            }
+        }
+
+        #[cfg(not(any(
+            feature = "esp32c3",
+            feature = "esp32c6",
+            feature = "esp32h2",
+            feature = "esp32s3"
+        )))]
+        with(|| {
+            PrinterUart::write_bytes_assume_cs(bytes);
+            PrinterUart::flush();
         })
     }
 }
 
 #[cfg(all(
-    feature = "jtag-serial",
+    any(feature = "jtag-serial", feature = "auto"),
     any(
         feature = "esp32c3",
         feature = "esp32c6",
@@ -154,8 +222,8 @@ mod serial_jtag_printer {
         true
     }
 
-    impl super::Printer {
-        pub fn write_bytes_assume_cs(&mut self, bytes: &[u8]) {
+    impl super::PrinterSerialJtag {
+        pub fn write_bytes_assume_cs(bytes: &[u8]) {
             if fifo_full() {
                 // The FIFO is full. Let's see if we can progress.
 
@@ -188,17 +256,17 @@ mod serial_jtag_printer {
             }
         }
 
-        pub fn flush(&mut self) {
+        pub fn flush() {
             fifo_flush();
         }
     }
 }
 
-#[cfg(all(feature = "uart", feature = "esp32"))]
+#[cfg(all(any(feature = "uart", feature = "auto"), feature = "esp32"))]
 mod uart_printer {
     const UART_TX_ONE_CHAR: usize = 0x4000_9200;
-    impl super::Printer {
-        pub fn write_bytes_assume_cs(&mut self, bytes: &[u8]) {
+    impl super::PrinterUart {
+        pub fn write_bytes_assume_cs(bytes: &[u8]) {
             for &b in bytes {
                 unsafe {
                     let uart_tx_one_char: unsafe extern "C" fn(u8) -> i32 =
@@ -208,14 +276,14 @@ mod uart_printer {
             }
         }
 
-        pub fn flush(&mut self) {}
+        pub fn flush() {}
     }
 }
 
-#[cfg(all(feature = "uart", feature = "esp32s2"))]
+#[cfg(all(any(feature = "uart", feature = "auto"), feature = "esp32s2"))]
 mod uart_printer {
-    impl super::Printer {
-        pub fn write_bytes_assume_cs(&mut self, bytes: &[u8]) {
+    impl super::PrinterUart {
+        pub fn write_bytes_assume_cs(bytes: &[u8]) {
             // On ESP32-S2 the UART_TX_ONE_CHAR ROM-function seems to have some issues.
             for chunk in bytes.chunks(64) {
                 for &b in chunk {
@@ -234,11 +302,14 @@ mod uart_printer {
             }
         }
 
-        pub fn flush(&mut self) {}
+        pub fn flush() {}
     }
 }
 
-#[cfg(all(feature = "uart", not(any(feature = "esp32", feature = "esp32s2"))))]
+#[cfg(all(
+    any(feature = "uart", feature = "auto"),
+    not(any(feature = "esp32", feature = "esp32s2"))
+))]
 mod uart_printer {
     trait Functions {
         const TX_ONE_CHAR: usize;
@@ -350,8 +421,8 @@ mod uart_printer {
         }
     }
 
-    impl super::Printer {
-        pub fn write_bytes_assume_cs(&mut self, bytes: &[u8]) {
+    impl super::PrinterUart {
+        pub fn write_bytes_assume_cs(bytes: &[u8]) {
             for chunk in bytes.chunks(Device::CHUNK_SIZE) {
                 for &b in chunk {
                     Device::tx_byte(b);
@@ -361,7 +432,7 @@ mod uart_printer {
             }
         }
 
-        pub fn flush(&mut self) {}
+        pub fn flush() {}
     }
 }