Use arm toolchain and gdb multiarch from repo for rp2040

Added `libc_replacements` which stubs-out various unused newlib functions.
Without this, linker generates warnings like `_close is not implemented and will always fail`.
These functions aren't actually used anyway and are discarded during garbage collection.

Windows install unchanged; best solution is not to use Windows.

Sming/Arch/Rp2040/Components/libc/src/libc_replacements.c

@@ -0,0 +1,126 @@
+/*
+ libc_replacements.c - replaces libc functions with functions
+ from Espressif SDK
+
+ Copyright (c) 2015 Ivan Grokhotkov. All rights reserved.
+ This file is part of the esp8266 core for Arduino environment.
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+ Modified 03 April 2015 by Markus Sattler
+
+ */
+
+#include <stdio.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <sys/reent.h>
+#include <esp_attr.h>
+#include <m_printf.h>
+
+int _open_r(struct _reent* unused, const char* ptr, int mode)
+{
+	(void)unused;
+	(void)ptr;
+	(void)mode;
+	return 0;
+}
+
+int _close_r(struct _reent* unused, int file)
+{
+	(void)unused;
+	(void)file;
+	return 0;
+}
+
+int _fstat_r(struct _reent* unused, int file, struct stat* st)
+{
+	(void)unused;
+	(void)file;
+	st->st_mode = S_IFCHR;
+	return 0;
+}
+
+int _lseek_r(struct _reent* unused, int file, int ptr, int dir)
+{
+	(void)unused;
+	(void)file;
+	(void)ptr;
+	(void)dir;
+	return 0;
+}
+
+int _read_r(struct _reent* unused, int file, char* ptr, int len)
+{
+	(void)unused;
+	(void)file;
+	(void)ptr;
+	(void)len;
+	return 0;
+}
+
+int _write_r(struct _reent* r, int file, char* ptr, int len)
+{
+	(void)r;
+	if(file == STDOUT_FILENO) {
+		return m_nputs(ptr, len);
+	}
+	return 0;
+}
+
+int _putc_r(struct _reent* r, int c, FILE* file) __attribute__((weak));
+
+int _putc_r(struct _reent* r, int c, FILE* file)
+{
+	(void)r;
+	if(file->_file == STDOUT_FILENO) {
+		m_putc(c);
+		return c;
+	}
+	return EOF;
+}
+
+int puts(const char* str)
+{
+	m_puts(str);
+	m_putc('\n');
+	return 1;
+}
+
+#undef putchar
+int putchar(int c)
+{
+	m_putc(c);
+	return c;
+}
+
+void _exit(int status)
+{
+	(void)status;
+	abort();
+}
+
+int atexit(void (*func)())
+{
+	(void)func;
+	return 0;
+}
+
+void abort() __attribute((weak));
+void abort()
+{
+	for(;;) {
+	}
+}

Sming/Arch/Rp2040/Tools/install.sh

@@ -2,18 +2,19 @@
 #
 # Rp2040 install.sh
 
-$PKG_INSTALL ninja-build
+case $DIST in
+    debian)
+        $PKG_INSTALL \
+            ninja-build \
+            libstdc++-arm-none-eabi-newlib \
+            gdb-multiarch
+        ;;
 
-if [ -d "$PICO_TOOLCHAIN_PATH/arm-none-eabi" ]; then
-    printf "\n\n** Skipping Rp2040 tools installation: '$PICO_TOOLCHAIN_PATH' exists\n\n"
-else
-    TOOLCHAIN_VERSION="10.3-2021.10"
-    TOOLCHAIN_BASE_URL="https://developer.arm.com/-/media/Files/downloads/gnu-rm"
-    TOOLCHAIN_NAME="gcc-arm-none-eabi-$TOOLCHAIN_VERSION"
-    TOOLCHAIN_FILE="$TOOLCHAIN_NAME-$(uname -m)-linux.tar.bz2"
-    TOOLCHAIN_URL="$TOOLCHAIN_BASE_URL/$TOOLCHAIN_VERSION/$TOOLCHAIN_FILE"
-    $WGET "$TOOLCHAIN_URL" -O "$DOWNLOADS/$TOOLCHAIN_FILE"
-    mkdir -p "$PICO_TOOLCHAIN_PATH"
-    tar -jxf "$DOWNLOADS/$TOOLCHAIN_FILE" -C "$PICO_TOOLCHAIN_PATH" --totals --transform='s|^/*||'
-    mv "$PICO_TOOLCHAIN_PATH/$TOOLCHAIN_NAME/"* "$PICO_TOOLCHAIN_PATH"
-fi
+    fedora)
+        $PKG_INSTALL \
+            ninja-build \
+            arm-none-eabi-gcc-cs-c++ \
+            arm-none-eabi-newlib
+        ;;
+
+esac

Sming/Arch/Rp2040/build.mk

@@ -22,15 +22,16 @@ DEBUG_VARS += PICO_TOOLCHAIN_PATH
 ifdef PICO_TOOLCHAIN_PATH
 export PICO_TOOLCHAIN_PATH := $(call FixPath,$(PICO_TOOLCHAIN_PATH))
 TOOLSPEC := $(PICO_TOOLCHAIN_PATH)/bin/$(CONFIG_TOOLPREFIX)-
+GDB_TOOLSPEC := $(TOOLSPEC)
 ifeq (,$(wildcard $(PICO_TOOLCHAIN_PATH)/$(CONFIG_TOOLPREFIX)))
 $(error PICO_TOOLCHAIN_PATH not set correctly: $(PICO_TOOLCHAIN_PATH))
 endif
 else
-PICO_TOOLCHAIN_PATH := $(shell which $(CONFIG_TOOLPREFIX)-gcc)
-ifeq (,$(PICO_TOOLCHAIN_PATH))
+ifeq (,$(shell which $(CONFIG_TOOLPREFIX)-gcc))
 $(error Toolchain not found, maybe set PICO_TOOLCHAIN_PATH)
 endif
-TOOLSPEC := $(dir $(PICO_TOOLCHAIN_PATH))$(CONFIG_TOOLPREFIX)-
+TOOLSPEC := $(CONFIG_TOOLPREFIX)-
+GDB_TOOLSPEC :=
 endif
 
 # select which tools to use as assembler, compiler, librarian and linker
@@ -42,7 +43,7 @@ LD				:= $(TOOLSPEC)gcc
 NM				:= $(TOOLSPEC)nm
 OBJCOPY		 	:= $(TOOLSPEC)objcopy
 OBJDUMP		 	:= $(TOOLSPEC)objdump
-GDB				:= $(TOOLSPEC)gdb
+GDB				:= $(GDB_TOOLSPEC)gdb
 
 CPPFLAGS += \
 	-nostdlib

Tools/export.sh

@@ -36,6 +36,3 @@ export ESP_HOME=${ESP_HOME:=/opt/esp-quick-toolchain}
 # Esp32
 export IDF_PATH=${IDF_PATH:=/opt/esp-idf}
 export IDF_TOOLS_PATH=${IDF_TOOLS_PATH:=/opt/esp32}
-
-# Rp2040
-export PICO_TOOLCHAIN_PATH=${PICO_TOOLCHAIN_PATH:=/opt/rp2040}

docs/source/upgrading/5.1-5.2.rst

@@ -43,7 +43,17 @@ esp8266: https://github.com/earlephilhower/newlib-xtensa/blob/xtensa-4_0_0-lock-
 esp32: https://github.com/espressif/newlib-esp32/blob/esp-4.3.0/newlib/libc/
 
 
-**Esp32 IDF**
+**Toolchain versions updated**
 
-The installation scripts now install IDF version 5.2 by default.
-See :ref:`idf_versions` for further details.
+Esp8266
+    The installer has been updated to use the latest toolchain (Feb 23), gcc 10.3.
+
+Esp32 IDF
+    The installation scripts now install IDF version 5.2 by default.
+    See :ref:`idf_versions` for further details.
+
+RP2040
+    The installation scripts install the ARM toolchain available in your Linux distribution.
+
+    Previously it installed a version from ARMs developer website to /opt/rp2040 and set ``PICO_TOOLCHAIN_PATH`` accordingly.
+    With the new version there is no longer any need to set this environment variable.