Add RISC-V support, GCC 14 move (#2491)

* Adds RISC-V compilation option to the IDE and Platform.IO.
* Build RP2350-RISCV libpico, libbearssl
* Fix RP2350 BearSSL library (was copied from RP2040, now built for M33)
* New GCC 14.2 toolchain is required (12.4 RISC-V support is borked)
* Newlib locking fixed prototypes
* Manually force all runtime init code into RP2350 binaries
* Add RISC-V to CI
* Remove RP2350 BOOT2.S files, binaries (not used)
* Clean up minor GCC 14.x warnings
* Add RP2350-RISCV OTA build, link
* Add RISC-V FreeRTOS files (configuration still not running, but builds)
* Add basic documentation

Author: earlephilhower

.github/workflows/pull-request.yml

@@ -17,7 +17,7 @@ jobs:
       with:
         submodules: false
     - name: Run codespell
-      uses: codespell-project/actions-codespell@master
+      uses: codespell-project/actions-codespell@v2
       with:
         skip: ./ArduinoCore-API,./libraries/ESP8266SdFat,./libraries/Adafruit_TinyUSB_Arduino,./libraries/LittleFS/lib,./tools/pyserial,./pico-sdk,./.github,./docs/i2s.rst,./cores/rp2040/api,./libraries/FreeRTOS,./tools/libbearssl/bearssl,./include,./libraries/WiFi/examples/BearSSL_Server,./ota/uzlib,./libraries/http-parser/lib,./libraries/WebServer/examples/HelloServerBearSSL/HelloServerBearSSL.ino,./libraries/HTTPUpdateServer/examples/SecureBearSSLUpdater/SecureBearSSLUpdater.ino,./.git,./libraries/FatFS/lib/fatfs,./libraries/FatFS/src/diskio.h,./libraries/FatFS/src/ff.cpp,./libraries/FatFS/src/ffconf.h,./libraries/FatFS/src/ffsystem.cpp,./libraries/FatFS/src/ff.h,./libraries/lwIP_WINC1500/src/driver,./libraries/lwIP_WINC1500/src/common,./libraries/lwIP_WINC1500/src/bus_wrapper,./libraries/lwIP_WINC1500/src/spi_flash
         ignore_words_list: ser,dout,shiftIn,acount
@@ -101,6 +101,37 @@ jobs:
         cd ..
         bash ./tests/build-rp2350.sh
 
+# Build all rp2350-riscv examples on linux (core and Arduino IDE)
+  build-rp2350-riscv-linux:
+    name: Build RP2350-RISCV ${{ matrix.chunk }}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        chunk: [0, 1, 2, 3, 4, 5]
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        submodules: true
+    - uses: actions/setup-python@v5
+      with:
+        python-version: '3.x'
+    - name: Cache Linux toolchain
+      id: cache-linux
+      uses: actions/cache@v4
+      with:
+        path: ./tools/dist
+        key: ${{ runner.os }}-${{ hashFiles('package/package_pico_index.template.json', 'tests/common.sh') }}
+    - name: Build Sketches
+      env:
+        BUILD_PARITY: custom
+        mod: 6
+        rem: ${{ matrix.chunk }}
+      run: |
+        cd pico-sdk
+        git submodule update --init
+        cd ..
+        bash ./tests/build-rp2350-riscv.sh
+
 # Build TinyUSB examples, requires custom build command line
   build-tinyusb:
     name: Build TinyUSB Examples

README.md

@@ -4,7 +4,7 @@
 
 Raspberry Pi Pico Arduino core, for all RP2040 and RP2350 boards
 
-This is a port of Arduino to the RP2040 (Raspberry Pi Pico processor) and RP2350 (Raspberry Pi Pico 2 processor). It uses the bare Raspberry Pi Pico SDK and a custom GCC 12.3/Newlib 4.0 toolchain.
+This is a port of Arduino to the RP2040 (Raspberry Pi Pico processor) and RP2350 (Raspberry Pi Pico 2 processor). It uses the bare Raspberry Pi Pico SDK and a custom GCC 14.2/Newlib 4.3 toolchain and supports ARM and RISC-V cores.
 
 # Documentation
 See https://arduino-pico.readthedocs.io/en/latest/ along with the examples for more detailed usage information.
@@ -126,6 +126,7 @@ Read the [Contributing Guide](https://github.com/earlephilhower/arduino-pico/blo
 * Peripherals:  SPI master/slave, Wire(I2C) master/slave, dual UART, emulated EEPROM, I2S audio input/output, Servo
 * printf (i.e. debug) output over USB serial
 * Transparent use of PSRAM globals and heap (RP2350 only)
+* ARM or RISC-V (Hazard3) support for The RP2350
 
 The RP2040 PIO state machines (SMs) are used to generate jitter-free:
 * Servos

boards.txt

@@ -0,0 +1,4 @@
+.section .boot2, "ax"
+
+.global __boot2_entry_point
+__boot2_entry_point:

boot2/rp2350-riscv/none.S

@@ -0,0 +1,4 @@
+.section .boot2, "ax"
+
+.global __boot2_entry_point
+__boot2_entry_point:

boot2/rp2350/boot2_generic_03h_2_padded_checksum.S

@@ -37,7 +37,7 @@
 #ifdef abs
 #undef abs
 #endif // abs
-#ifdef __cplusplus
+#if defined(__cplusplus) && !defined(__riscv)
 using std::abs;
 using std::round;
 #else