Add PlatformIO support (#250)

* Add package.json

To make package easily integratable with PlatformIO

* Correct name back to original one

* Format package.json

* Add first shot at builder script

* Add USB stack flags, fix compile flags

* Formatting

* Add more link & USB flags

* Build Boot2 bootloader

* Formatting

* Generate linkerscript, linker fixes

* Fix linkflags, make firmware runnable

* Update USB flags and RAM size

* Correct USB flags, add dynamic sketch partitioning

* Restructure filesystem size and flash size logic into platform code

* Move C++ only flags to CXXFLAGS

* Add PlatformIO documentation

* Link to new platform.io document in the docs TOC

* Fix typos in platformio docs

* Fix one additional typo in platformio.rst

* Update docs

* Remove wrongly commited build folder

docs/index.rst

@@ -20,6 +20,8 @@ For the latest version, always check https://github.com/earlephilhower/arduino-p
    Installation <install>
    IDE Menus <ide>
 
+   Platform.IO Integration <platformio>
+
    Pin (Re)Assignment <pins>
 
    Analog I/O <analog>

docs/platformio.rst

+Using this core with PlatformIO
+===============================
+
+What is PlatformIO? 
+-------------------
+
+`PlatformIO <https://platformio.org/>`__  is a free, open-source build-tool written in Python, which also integrates into VSCode code as an extension.
+
+PlatformIO significantly simplifies writing embedded software by offering a unified build system, yet being able to create project files for many different IDEs, including VSCode, Eclipse, CLion, etc. 
+Through this, PlatformIO can offer extensive features such as IntelliSense (autocomplete), debugging, unit testing etc., which not available in the standard Arduino IDE.
+
+The Arduino IDE experience:
+
+.. image:: images/the_arduinoide_experience.png
+
+The PlatformIO experience:
+
+.. image:: images/the_platformio_experience.png
+
+Refer to the general documentation at https://docs.platformio.org/.
+
+Especially useful is the `Getting started with VSCode + PlatformIO <https://docs.platformio.org/en/latest/integration/ide/vscode.html#installation), [CLI reference](https://docs.platformio.org/en/latest/core/index.html) and [platformio.ini options](https://docs.platformio.org/en/latest/projectconf/index.html)>`__ page.
+
+Hereafter it is assumed that you have a basic understanding of PlatformIO in regards to project creation, project file structure and building and uploading PlatformIO projects, through reading the above pages.
+
+Current state of development
+----------------------------
+
+At the time of writing, PlatformIO integration for this core is a work-in-progress and not yet merged into mainline PlatformIO. This is subject to change soon.
+
+If you want to use the PlatformIO integration right now, make sure you first create a standard Raspberry Pi Pico + Arduino project within PlatformIO. 
+This will give you a project with the ``platformio.ini`` 
+
+.. code:: ini
+
+    [env:pico]
+    platform = raspberrypi
+    board = pico
+    framework = arduino
+
+Here, you need to change the `platform` to take advantage of the features described hereunder. 
+You *also* need to inject two PlatformIO packages, one for the compiler toolchain and one for the Arduino core package.
+
+.. code:: ini
+
+    [env:pico]
+    platform = https://github.com/maxgerhardt/platform-raspberrypi.git
+    board = pico
+    framework = arduino
+    ; note that download link for toolchain is specific for OS. see https://github.com/earlephilhower/pico-quick-toolchain/releases.
+    platform_packages = 
+        maxgerhardt/framework-arduinopico@https://github.com/earlephilhower/arduino-pico.git
+        maxgerhardt/toolchain-pico@https://github.com/earlephilhower/pico-quick-toolchain/releases/download/1.3.1-a/x86_64-w64-mingw32.arm-none-eabi-7855b0c.210706.zip
+    
+When the support for this core has been merged into mainline PlatformIO, this notice will be removed and a standard `platformio.ini` as shown above will work as a base.
+
+Selecting the new core
+----------------------
+
+Prerequisite for using this core is to tell PlatformIO to switch to it.
+There will be board definition files where the Earle-Philhower core will
+be the default since it's a board that only exists in this core (and not
+the other https://github.com/arduino/ArduinoCore-mbed). To switch boards
+for which this is not the default core (e.g. the standard
+``board = pico``), the directive
+
+.. code:: ini
+
+    board_build.core = earlephilhower
+
+must be added to the ``platformio.ini``. This controls the `core
+switching
+logic <https://github.com/maxgerhardt/platform-raspberrypi/blob/77e0d3a29d1dbf00fd3ec3271104e3bf4820869c/builder/frameworks/arduino/arduino.py#L27-L32>`__.
+
+Flash size
+----------
+
+Controlled via specifying the size allocated for the filesystem.
+Available sketch size is calculated accordingly by using (as in
+``makeboards.py``) that number and the (constant) EEPROM size (4096
+bytes) and the total flash size as known to PlatformIO via the board
+definition file. The expression on the right can involve "b","k","m"
+(bytes/kilobytes/megabytes) and floating point numbers. This makes it
+actually more flexible than in the Arduino IDE where there is a finite
+list of choices. Calculations happen in `the
+platform <https://github.com/maxgerhardt/platform-raspberrypi/blob/77e0d3a29d1dbf00fd3ec3271104e3bf4820869c/builder/main.py#L118-L184>`__.
+
+.. code:: ini
+
+    ; in reference to a board = pico config (2MB flash)
+    ; Flash Size: 2MB (Sketch: 1MB, FS:1MB)
+    board_build.filesystem_size = 1m
+    ; Flash Size: 2MB (No FS)
+    board_build.filesystem_size = 0m
+    ; Flash Size: 2MB (Sketch: 0.5MB, FS:1.5MB)
+    board_build.filesystem_size = 1.5m
+
+CPU Speed
+---------
+
+As for all other PlatformIO platforms, the ``f_cpu`` macro value (which
+is passed to the core) can be changed as
+`documented <https://docs.platformio.org/en/latest/boards/raspberrypi/pico.html#configuration>`__
+
+.. code:: ini
+
+    ; 133MHz
+    board_build.f_cpu = 133000000L
+
+Debug Port
+----------
+
+Via
+`build_flags <https://docs.platformio.org/en/latest/projectconf/section_env_build.html#build-flags>`__
+as done for many other cores
+(`example <https://docs.platformio.org/en/latest/platforms/ststm32.html#configuration>`__).
+
+.. code:: ini
+
+    ; Debug Port: Serial
+    build_flags = -DDEBUG_RP2040_PORT=Serial
+    ; Debug Port: Serial 1
+    build_flags = -DDEBUG_RP2040_PORT=Serial1
+    ; Debug Port: Serial 2
+    build_flags = -DDEBUG_RP2040_PORT=Serial2
+
+Debug Level
+-----------
+
+Done again by directly adding the needed `build
+flags <https://github.com/earlephilhower/arduino-pico/blob/05356da2c5552413a442f742e209c6fa92823666/boards.txt#L104-L114>`__.
+When wanting to define multiple build flags, they must be accumulated in
+either a sing line or a newline-separated expression.
+
+.. code:: ini
+
+    ; Debug level: Core
+    build_flags = -DDEBUG_RP2040_CORE
+    ; Debug level: SPI
+    build_flags = -DDEBUG_RP2040_SPI
+    ; Debug level: Wire
+    build_flags = -DDEBUG_RP2040_WIRE
+    ; Debug level: All
+    build_flags = -DDEBUG_RP2040_WIRE -DDEBUG_RP2040_SPI -DDEBUG_RP2040_CORE
+    ; Debug level: NDEBUG
+    build_flags = -DNDEBUG
+
+    ; example: Debug port on serial 2 and all debug output
+    build_flags = -DDEBUG_RP2040_WIRE -DDEBUG_RP2040_SPI -DDEBUG_RP2040_CORE -DDEBUG_RP2040_PORT=Serial2
+    ; equivalent to above
+    build_flags = 
+       -DDEBUG_RP2040_WIRE
+       -DDEBUG_RP2040_SPI
+       -DDEBUG_RP2040_CORE
+       -DDEBUG_RP2040_PORT=Serial2
+
+USB Stack
+---------
+
+Not specifying any special build flags regarding this gives one the
+default Pico SDK USB stack. To change it, add
+
+.. code:: ini
+
+    ; Adafruit TinyUSB
+    build_flags = -DUSE_TINYUSB
+    ; No USB stack
+    build_flags = -DPIO_FRAMEWORK_ARDUINO_NO_USB
+
+Note that the special "No USB" setting is also supported, through the
+shortcut-define ``PIO_FRAMEWORK_ARDUINO_NO_USB``.
+
+
+Selecting a different core version
+----------------------------------
+
+If you wish to use a different version of the core, e.g., the latest git
+``master`` version, you can use a
+`platform_packages <https://docs.platformio.org/en/latest/projectconf/section_env_platform.html#platform-packages>`__
+directive to do so. Simply specify that the framework package
+(``framework-arduinopico``) comes from a different source.
+
+.. code:: ini
+
+    platform_packages =
+       framework-arduinopico@https://github.com/earlephilhower/arduino-pico.git#master
+
+Whereas the ``#master`` can also be replaced by a ``#branchname`` or a
+``#commithash``. If left out, it will pull the default branch, which is ``master``.
+
+The ``file://`` pseudo-protocol can also be used instead of ``https://`` to point to a
+local copy of the core (with e.g. some modifications) on disk.
+
+Note that this can only be done for versions that have the PlatformIO
+builder script it in, so versions before 1.9.2 are not supported.
+
+Examples 
+--------
+
+The following example ``platformio.ini`` can be used for a Raspberry Pi Pico
+and 0.5MByte filesystem. 
+
+.. code:: ini
+
+    [env:pico]
+    platform = https://github.com/maxgerhardt/platform-raspberrypi.git
+    board = pico
+    framework = arduino
+    build_board.core = earlephilhower
+    board_build.filesystem_size = 0.5m
+    ; note that download link for toolchain is specific for OS. see https://github.com/earlephilhower/pico-quick-toolchain/releases.
+    platform_packages = 
+        maxgerhardt/framework-arduinopico@https://github.com/earlephilhower/arduino-pico.git
+        maxgerhardt/toolchain-pico@https://github.com/earlephilhower/pico-quick-toolchain/releases/download/1.3.1-a/x86_64-w64-mingw32.arm-none-eabi-7855b0c.210706.zip
+
+
+The initial project structure should be generated just creating a new
+project for the Pico and the Arduino framework, after which the
+auto-generated ``platformio.ini`` can be adapted per above.

package.json

 {
   "name": "framework-arduinopico",
+  "version": "1.10903.0",
   "description": "Arduino Wiring-based Framework (RPi Pico RP2040)",
-    "url": "https://github.com/earlephilhower/arduino-pico",
-    "version": "0.9.2"
+  "keywords": [
+    "framework",
+    "arduino",
+    "Cortex-M",
+    "Raspberry Pi",
+    "RP2040"
+  ],
+  "homepage": "https://arduino-pico.readthedocs.io/en/latest/",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/earlephilhower/arduino-pico"
+  }
 }

tools/platformio-build.py

+# Copyright 2021-present Maximilian Gerhardt <maximilian.gerhardt@rub.de>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os, re, sys
+from SCons.Script import DefaultEnvironment, Builder, AlwaysBuild
+
+env = DefaultEnvironment()
+platform = env.PioPlatform()
+board = env.BoardConfig()
+upload_protocol = env.subst("$UPLOAD_PROTOCOL") or "picotool"
+ram_size = board.get("upload.maximum_ram_size")
+
+FRAMEWORK_DIR = platform.get_package_dir("framework-arduinopico")
+assert os.path.isdir(FRAMEWORK_DIR)
+
+# update progsize expression to also check for bootloader.
+env.Replace(
+    SIZEPROGREGEXP=r"^(?:\.boot2|\.text|\.data|\.rodata|\.text.align|\.ARM.exidx)\s+(\d+).*"
+)
+
+env.Append(
+    ASFLAGS=env.get("CCFLAGS", [])[:],
+
+    CCFLAGS=[
+        "-Werror=return-type",
+        "-march=armv6-m",
+        "-mcpu=cortex-m0plus",
+        "-mthumb",
+        "-ffunction-sections",
+        "-fdata-sections",
+        "-iprefix" + os.path.join(FRAMEWORK_DIR),
+        "@%s" % os.path.join(FRAMEWORK_DIR, "lib", "platform_inc.txt")
+    ],
+
+    CFLAGS=[
+        "-std=gnu17"
+    ],
+
+    CXXFLAGS=[
+        "-std=gnu++17",
+        "-fno-exceptions",
+        "-fno-rtti",
+    ],
+
+    CPPDEFINES=[
+        ("ARDUINO", 10810),
+        "ARDUINO_ARCH_RP2040",
+        ("F_CPU", "$BOARD_F_CPU"),
+        ("BOARD_NAME", '\\"%s\\"' % env.subst("$BOARD")),
+    ],
+
+    CPPPATH=[
+        os.path.join(FRAMEWORK_DIR, "cores", "rp2040"),
+        os.path.join(FRAMEWORK_DIR, "cores", "rp2040", "api", "deprecated"),
+        os.path.join(FRAMEWORK_DIR, "cores", "rp2040",
+                     "api", "deprecated-avr-comp")
+    ],
+
+    LINKFLAGS=[
+        "-march=armv6-m",
+        "-mcpu=cortex-m0plus",
+        "-mthumb",
+        "@%s" % os.path.join(FRAMEWORK_DIR, "lib", "platform_wrap.txt"),
+        "-u_printf_float",
+        "-u_scanf_float",
+        # no cross-reference table, heavily spams the output
+        # "-Wl,--cref",
+        "-Wl,--check-sections",
+        "-Wl,--gc-sections",
+        "-Wl,--unresolved-symbols=report-all",
+        "-Wl,--warn-common"
+    ],
+
+    LIBSOURCE_DIRS=[os.path.join(FRAMEWORK_DIR, "libraries")],
+
+    LIBPATH=[
+        os.path.join(FRAMEWORK_DIR, "lib")
+    ],
+
+    # link lib/libpico.a
+    LIBS=["pico", "m", "c", "stdc++", "c"]
+)
+
+
+def configure_usb_flags(cpp_defines):
+    global ram_size
+    if "USE_TINYUSB" in cpp_defines:
+        env.Append(CPPPATH=[os.path.join(
+            FRAMEWORK_DIR, "libraries", "Adafruit_TinyUSB_Arduino", "src", "arduino")])
+    elif "PIO_FRAMEWORK_ARDUINO_NO_USB" in cpp_defines:
+        env.Append(
+            CPPPATH=[os.path.join(FRAMEWORK_DIR, "tools", "libpico")],
+            CPPDEFINES=[
+                "NO_USB",
+                "DISABLE_USB_SERIAL" 
+            ]
+        )
+        # do not further add more USB flags or update sizes. no USB used.
+        return
+    else:
+        # standard Pico SDK USB stack used.
+        env.Append(CPPPATH=[os.path.join(FRAMEWORK_DIR, "tools", "libpico")])
+    # in any case, add standard flags
+    # preferably use USB information from arduino.earlephilhower section,
+    # but fallback to sensible values derived from other parts otherwise.
+    usb_pid = board.get("build.arduino.earlephilhower.usb_pid",
+                        board.get("build.hwids", [[0, 0]])[0][1])
+    usb_vid = board.get("build.arduino.earlephilhower.usb_vid",
+                        board.get("build.hwids", [[0, 0]])[0][0])
+    usb_manufacturer = board.get(
+        "build.arduino.earlephilhower.usb_manufacturer", board.get("vendor", "Raspberry Pi"))
+    usb_product = board.get(
+        "build.arduino.earlephilhower.usb_product", board.get("name", "Pico"))
+
+    # Copy logic from makeboards.py. 
+    # Depending on whether a certain upload / debug method is used, change
+    # the PID/VID.
+    # https://github.com/earlephilhower/arduino-pico/blob/master/tools/makeboards.py
+    vidtouse = usb_vid
+    pidtouse = usb_pid
+    if upload_protocol == "picoprobe": 
+        pidtouse = '0x0004'
+    elif upload_protocol == "picodebug":
+        vidtouse = '0x1209'
+        pidtouse = '0x2488'
+        ram_size = 240 * 1024
+
+    env.Append(CPPDEFINES=[
+        ("CFG_TUSB_MCU", "OPT_MCU_RP2040"),
+        ("USB_VID", usb_vid),
+        ("USB_PID", usb_pid),
+        ("USB_MANUFACTURER", '\\"%s\\"' % usb_manufacturer),
+        ("USB_PRODUCT", '\\"%s\\"' % usb_product),
+        ("SERIALUSB_PID", usb_pid)
+    ])
+
+    # use vidtouse and pidtouse 
+    # for USB PID/VID autodetection
+    hw_ids = board.get("build.hwids", [["0x2E8A", "0x00C0"]])
+    hw_ids[0][0] = vidtouse
+    hw_ids[0][1] = pidtouse
+    board.update("build.hwids", hw_ids)
+    board.update("upload.maximum_ram_size", ram_size)
+
+#
+# Process configuration flags
+#
+cpp_defines = env.Flatten(env.get("CPPDEFINES", []))
+
+configure_usb_flags(cpp_defines)
+
+# info about the filesystem is already parsed by the platform's main.py 
+# script. We can just use the info here
+ 
+linkerscript_cmd = env.Command(
+    os.path.join("$BUILD_DIR", "memmap_default.ld"),  # $TARGET
+    os.path.join(FRAMEWORK_DIR, "lib", "memmap_default.ld"),  # $SOURCE
+    env.VerboseAction(" ".join([
+        '"$PYTHONEXE" "%s"' % os.path.join(
+            FRAMEWORK_DIR, "tools", "simplesub.py"),
+        "--input", "$SOURCE",
+        "--out", "$TARGET",
+        "--sub", "__FLASH_LENGTH__", "$PICO_FLASH_LENGTH",
+        "--sub", "__EEPROM_START__", "$PICO_EEPROM_START",
+        "--sub", "__FS_START__", "$FS_START",
+        "--sub", "__FS_END__", "$FS_END",
+        "--sub", "__RAM_LENGTH__", "%dk" % (ram_size // 1024),
+    ]), "Generating linkerscript $BUILD_DIR/memmap_default.ld")
+)
+
+# if no custom linker script is provided, we use the command that we prepared to generate one.
+if not board.get("build.ldscript", ""):
+    # execute fetch filesystem info stored in env to alawys have that info ready
+    env["fetch_fs_size"](env)
+    env.Depends("$BUILD_DIR/${PROGNAME}.elf", linkerscript_cmd)
+    env.Replace(LDSCRIPT_PATH=os.path.join("$BUILD_DIR", "memmap_default.ld"))
+
+libs = []
+
+variant = board.get("build.arduino.earlephilhower.variant", board.get("build.variant", None))
+
+if variant is not None:
+    env.Append(CPPPATH=[
+        os.path.join(FRAMEWORK_DIR, "variants", variant)
+    ])
+
+    libs.append(
+        env.BuildLibrary(
+            os.path.join("$BUILD_DIR", "FrameworkArduinoVariant"),
+            os.path.join(FRAMEWORK_DIR, "variants", variant)))
+
+libs.append(
+    env.BuildLibrary(
+        os.path.join("$BUILD_DIR", "FrameworkArduino"),
+        os.path.join(FRAMEWORK_DIR, "cores", "rp2040")))
+
+bootloader_src_file = board.get(
+    "build.arduino.earlephilhower.boot2_source", "boot2_generic_03h_2_padded_checksum.S")
+
+# Add bootloader file (boot2.o)
+# Only build the needed .S file, exclude all others via src_filter.
+env.BuildSources(
+    os.path.join("$BUILD_DIR", "FrameworkArduinoBootloader"),
+    os.path.join(FRAMEWORK_DIR, "boot2"),
+    "-<*> +<%s>" % bootloader_src_file,
+)
+# Add include flags for all .S assembly file builds
+env.Append(
+    ASFLAGS=[
+        "-I", os.path.join(FRAMEWORK_DIR, "pico-sdk", "src",
+                           "rp2040", "hardware_regs", "include"),
+        "-I", os.path.join(FRAMEWORK_DIR, "pico-sdk", "src",
+                           "common", "pico_binary_info", "include")
+    ]
+)
+
+env.Prepend(LIBS=libs)