bootloader: switch to baremetal

The pico-sdk kept causing issues with the psram-bootloader project.
Drop the pico-sdk and move to a custom baremetal bootloader.

Signed-off-by: Jesse Taube <Mr.Bossman075@gmail.com>

Author: Mr-Bossman

.gitignore

@@ -1,2 +1,4 @@
-psram-bootloader/build
-psram-bootloader/demo/build
+package/pico2-bootloader/bootloader/build
+package/pico2-bootloader/bootloader/*.uf2
+package/pico2-bootloader/bootloader/*.bin
+package/pico2-bootloader/bootloader/demo/build

Config.in

@@ -1 +1 @@
-
+source "$BR2_EXTERNAL_RPI_PICO2_PATH/package/pico2-bootloader/Config.in"

Dockerfile

@@ -1,21 +1,15 @@
 FROM ubuntu:24.04
-RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates patch git make binutils gcc g++ file wget cpio unzip rsync bc bzip2 g++ cmake python3 && \
+RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates patch git make binutils gcc file wget cpio unzip rsync bc bzip2 g++ && \
 	rm -rf /var/lib/apt/lists/* && \
 	apt-get clean
 
-RUN wget https://github.com/raspberrypi/pico-sdk-tools/releases/download/v2.0.0-5/riscv-toolchain-14-x86_64-lin.tar.gz && \
-	mkdir -p ~/toolchain && \
-	tar -vxzf riscv-toolchain-14-x86_64-lin.tar.gz -C ~/toolchain && \
-	rm riscv-toolchain-14-x86_64-lin.tar.gz
-
 RUN git clone --recurse-submodules https://github.com/Mr-Bossman/pi-pico2-linux
 
 WORKDIR pi-pico2-linux
 RUN make -C buildroot BR2_EXTERNAL=$PWD/ raspberrypi-pico2_defconfig && \
-	make -C buildroot && \
-	PICO_TOOLCHAIN_PATH=~/toolchain/ PICO_SDK_FETCH_FROM_GIT=1 make -C psram-bootloader
+	make -C buildroot
 
-CMD make -C psram-bootloader flash-kernel
+CMD picotool load -fu buildroot/output/images/flash-image.uf2
 
 # docker build -t pi-pico2-linux .
 # docker run -v $(pwd):/root/ -it --entrypoint /bin/bash pi-pico2-linux

README.md

@@ -15,27 +15,13 @@ make -C buildroot BR2_EXTERNAL=$PWD/ raspberrypi-pico2_defconfig
 
 make -C buildroot
 
-make -C psram-bootloader flash-kernel
+picotool load -fu buildroot/output/images/flash-image.uf2
 ```
 
 ## Designed to work with [SparkFun Pro Micro - RP2350](https://www.sparkfun.com/products/24870)
 
 ![Image of boot](images/booting.png)
 
-#### NOTES on SDK
-This project uses the sdk and tools installed to `~/.pico-sdk/`.
-To use the tools and sdk installed to another location see [this issue](https://github.com/raspberrypi/pico-sdk/pull/1820#issuecomment-2291611448)
-or the following.
-
-```bash
-export PICO_SDK_PATH=~/example_sdk/sdk/2.0.0/
-export PICO_TOOLCHAIN_PATH=~/example_sdk/toolchain/13_2_Rel1
-export pioasm_DIR=~/example_sdk/tools/2.0.0/pioasm
-export picotool_DIR=~/example_sdk/picotool/2.0.0/picotool
-
-make flash-kernel
-```
-
 #### NOTES on Atomics
 On page 307 of the RP2350 Datasheet MCAUSE register CODE 7 says:
 > Store/AMO access fault. A store/AMO failed a PMP check, or
@@ -50,8 +36,5 @@ Most implementations assume `lr` and `sr` will eventually succeed.
 
 This only works on the RP2350 RISC-V cores.
 
-If you want to run this on other boards, please change the `PICO_BOARD` variable in `CMakeLists.txt`.
-`set(PICO_BOARD sparkfun_promicro_rp2350 CACHE STRING "Board type")`
-
-You will also need to set the psram CS pin with the `SFE_RP2350_XIP_CSI_PIN` macro in `bootloader.c`.
+If you want to run this on other boards, please change the psram CS pin with the `RP2350_XIP_CSI_PIN` macro in `package/pico2-bootloader/bootloader/src/main.c`.
 As of now the only psram chip tested is the `APS6404L` and any others may not work.

board/raspberrypi/raspberrypi-pico2/genimage.cfg

@@ -3,10 +3,15 @@ image flash-image.bin {
 		partition-table-type = "none"
 	}
 
+	partition bootloader {
+		in-partition-table = "no"
+		image = "bootloader.bin"
+		offset = 0
+	}
+
 	partition raspberrypi-pico2.dtb {
 		in-partition-table = "no"
 		image = "raspberrypi-pico2.dtb"
-		offset = 0
 	}
 
 	partition Image {

board/raspberrypi/raspberrypi-pico2/post-build.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+shift
+support/scripts/genimage.sh "$@"
+
+if picotool version > /dev/null; then
+	picotool uf2 convert "${BINARIES_DIR}/flash-image.bin" \
+		"${BINARIES_DIR}/flash-image.uf2" --family rp2350-riscv
+else
+	echo "picotool not found, skipping uf2 conversion"
+	echo "Please run \`picotool uf2 convert ${BINARIES_DIR}/flash-image.bin \
+		${BINARIES_DIR}/flash-image.uf2 --family rp2350-riscv\` insead."
+fi
+tput smso 2>/dev/null
+echo "Run \`picotool load -fu ${BINARIES_DIR}/flash-image.uf2\` to flash to pi pico2."
+tput rmso 2>/dev/null

board/raspberrypi/raspberrypi-pico2/post-image.sh

@@ -15,10 +15,12 @@ BR2_OPTIMIZE_S=y
 BR2_TARGET_ROOTFS_INITRAMFS=y
 BR2_ROOTFS_OVERLAY="$(BR2_EXTERNAL)/board/raspberrypi/raspberrypi-pico2/rootfs_overlay"
 
+# Bootloader
+BR2_PACKAGE_PICO2_BOOTLOADER=y
+
 # Image
-BR2_ROOTFS_POST_IMAGE_SCRIPT="support/scripts/genimage.sh"
-BR2_ROOTFS_POST_BUILD_SCRIPT="$(BR2_EXTERNAL)/board/raspberrypi/raspberrypi-pico2/post-build.sh"
-BR2_ROOTFS_POST_SCRIPT_ARGS="-c $(BR2_EXTERNAL)/board/raspberrypi/raspberrypi-pico2/genimage.cfg"
+BR2_ROOTFS_POST_IMAGE_SCRIPT="$(BR2_EXTERNAL)/board/raspberrypi/raspberrypi-pico2/post-image.sh"
+BR2_ROOTFS_POST_IMAGE_SCRIPT_ARGS="-c $(BR2_EXTERNAL)/board/raspberrypi/raspberrypi-pico2/genimage.cfg"
 
 # Linux headers same as kernel
 BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_6_15=y

configs/raspberrypi-pico2_defconfig

@@ -0,0 +1,5 @@
+config BR2_PACKAGE_PICO2_BOOTLOADER
+	bool "raspberry pi pico 2 bootloader"
+	help
+		Custom bootloader for raspberry pi pico 2
+		to load linux.

package/pico2-bootloader/Config.in

@@ -42,22 +42,25 @@ pico_sdk_init()
 
 # Add executable. Default name is the project name, version 0.1
 
+add_compile_definitions(PICO_SDK)
+
+include_directories(psram-bootloader
+	src
+)
+
 add_executable(psram-bootloader
-    src/bootloader.c
-    )
+	src/main.c
+	src/image.c
+	src/qmi.c
+)
 
 # pull in common dependencies
 target_link_libraries(psram-bootloader pico_stdlib)
 
 pico_enable_stdio_usb(psram-bootloader 1)
 pico_enable_stdio_uart(psram-bootloader 1)
 
-# add partition table
-pico_embed_pt_in_binary(psram-bootloader ${CMAKE_CURRENT_LIST_DIR}/partition_table.json)
-
-# create absolute uf2, and package in flash
-pico_set_uf2_family(psram-bootloader "absolute")
-pico_package_uf2_output(psram-bootloader 0x10000000)
+pico_set_binary_type(psram-bootloader copy_to_ram)
 
 # create map/bin/hex file etc.
 pico_add_extra_outputs(psram-bootloader)