Clean up directory organization, libpico build (#129)

Also add a README.md to the tools directory.

Author: earlephilhower

lib/libpico.a

@@ -1,5 +1,5 @@
 -iwithprefixbefore/cores/rp2040/api/deprecated-avr-comp/
--iwithprefixbefore/pico_base/
+-iwithprefixbefore/lib/pico_base/
 -iwithprefixbefore/pico-examples/build/generated/pico_base
 -iwithprefixbefore/pico-extras/src/common/pico_audio/include
 -iwithprefixbefore/pico-extras/src/common/pico_util_buffer/include

pico_base/pico/config_autogen.h renamed to lib/pico_base/pico/config_autogen.h

@@ -0,0 +1,35 @@
+# Tools directory for the RP2040 Arduino-Pico
+
+# get.py
+Downloads and installs the toolchain into a GIT clone of the repo.  Run
+once after the `git clone` and any time the toolchain JSON file updates.
+The `dist` directory caches downloaded toolchain files.
+
+# discovery.py
+Run in the background by the IDE to scan for UF2 drives to show in the
+menus.  Normally not run manually by the user.
+
+# uf2conv.py
+Manages the upload of the UF2 formatted file to the board.  Called as part
+of the IDE upload process.  Will optionally send the serial reset signal
+to get the board into update mode (1200bps connection).
+
+# simplesub.py
+Very dumb `sed`-like tool used by the platform scripts to generate the
+linker `.ld` file (replacing the EEPROM location, FS sizes, etc.).
+Because we run on Windows, Mac, and Linux, need to provide this and not
+rely on existance of `sed` command.
+
+# pyserial
+`git clone` of the PySerial Python3 library to be used by the IDE.
+
+# makeboards.py
+Generates `boards.txt` programmatically.  Never edit the `boards.txt` file
+manually, use `python3 tools/makeboards.py > boards.py`.  Change the script
+as necessary to add any add'l fields or menus required.  Used because the
+`boards.txt` file is very repetitive and it's safer to generate with code
+than by hand.
+
+# libpico/make-libpico.sh
+Builds the libpico.a file as well as the bootloader stage2 binaries.
+Run whenever the pico-sdk is updated.

pico_base/pico/version.h renamed to lib/pico_base/pico/version.h

@@ -72,7 +72,7 @@ target_link_libraries(pico
 )
 
 add_custom_command(TARGET pico PRE_BUILD
-	COMMAND ../../system/arm-none-eabi/bin/arm-none-eabi-gcc -g -c ../../assembly/crt0.S  -I ../../pico-sdk/src/rp2040/hardware_regs/include -I ../../pico-sdk/src/common/pico_binary_info/include/
+	COMMAND arm-none-eabi-gcc -g -c ../../../assembly/crt0.S -I "${PICO_SDK_PATH}/src/rp2040/hardware_regs/include" -I "${PICO_SDK_PATH}/src/common/pico_binary_info/include/"
 )
 
 add_custom_command(TARGET pico POST_BUILD

lib/platform_inc.txt

@@ -0,0 +1,45 @@
+#!/bin/bash
+
+set -e # Exit on error
+
+export PICO_SDK_PATH="$(cd ../../pico-sdk/; pwd)"
+export PATH="$(cd ../../system/arm-none-eabi/bin; pwd):$PATH"
+
+rm -rf build
+mkdir build
+cd build
+cmake ..
+make -j
+mv libpico.a ../../../lib/.
+mv generated/pico_base/pico/version.h ../../../lib/pico_base/pico/.
+
+rm -rf boot
+mkdir boot
+cd boot
+mkdir -p pico 
+touch pico/config.h
+for type in boot2_generic_03h boot2_is25lp080 boot2_w25q080 boot2_w25x10cl; do
+    for div in 2 4; do
+        arm-none-eabi-gcc -march=armv6-m -mcpu=cortex-m0plus -mthumb -O3 \
+                         -DNDEBUG -DPICO_FLASH_SPI_CLKDIV=$div \
+                         -c "$PICO_SDK_PATH/src/rp2_common/boot_stage2/$type.S" \
+                         -I "$PICO_SDK_PATH/src/rp2040/hardware_regs/include/" \
+                         -I "$PICO_SDK_PATH/src/rp2_common/pico_platform/include/" \
+                         -I "$PICO_SDK_PATH/src/rp2_common/boot_stage2/asminclude/" \
+                         -I .
+
+        arm-none-eabi-gcc -march=armv6-m -mcpu=cortex-m0plus -mthumb -O3 \
+                          -DNDEBUG -Wl,--build-id=none --specs=nosys.specs -nostartfiles \
+                          -Wl,--script="$PICO_SDK_PATH/src/rp2_common/boot_stage2/boot_stage2.ld" \
+                          -Wl,-Map=$type.$div.elf.map $type.o -o $type.$div.elf 
+
+        arm-none-eabi-objdump -h $type.$div.elf >  $type.$div.dis
+        arm-none-eabi-objdump -d $type.$div.elf >> $type.$div.dis
+
+        arm-none-eabi-objcopy -Obinary $type.$div.elf $type.$div.bin
+
+        python3 "$PICO_SDK_PATH/src/rp2_common/boot_stage2/pad_checksum" \
+                   -s 0xffffffff $type.$div.bin ${type}_${div}_padded_checksum.S
+    done
+done
+mv *.S ../../../../assembly/.