In-app flash write, UF2 parser, remove picotool dependency, reboot command

lib/uf2/uf2.go

@@ -0,0 +1,71 @@
+package uf2
+
+import (
+	"encoding/binary"
+	"fmt"
+	"os"
+	"sort"
+)
+
+const (
+	blockSize = 512
+	magic0    = 0x0A324655
+	magic1    = 0x9E5D5157
+	magicEnd  = 0x0AB16F30
+
+	flagNotMainFlash       = 0x00000001
+	flagFamilyIDPresent    = 0x00002000
+	absoluteFamilyID       = 0xe48bff57
+)
+
+type Block struct {
+	Addr uint32
+	Data []byte
+}
+
+func Parse(path string) ([]Block, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	if len(data)%blockSize != 0 {
+		return nil, fmt.Errorf("file size %d not multiple of %d", len(data), blockSize)
+	}
+
+	var blocks []Block
+	for i := 0; i < len(data); i += blockSize {
+		b := data[i : i+blockSize]
+		m0 := binary.LittleEndian.Uint32(b[0:4])
+		m1 := binary.LittleEndian.Uint32(b[4:8])
+		me := binary.LittleEndian.Uint32(b[508:512])
+		if m0 != magic0 || m1 != magic1 || me != magicEnd {
+			return nil, fmt.Errorf("block %d: bad magic", i/blockSize)
+		}
+		flags := binary.LittleEndian.Uint32(b[8:12])
+		if flags&flagNotMainFlash != 0 {
+			continue
+		}
+		if flags&flagFamilyIDPresent != 0 {
+			familyID := binary.LittleEndian.Uint32(b[28:32])
+			if familyID == absoluteFamilyID {
+				continue
+			}
+		}
+		addr := binary.LittleEndian.Uint32(b[12:16])
+		size := binary.LittleEndian.Uint32(b[16:20])
+		if size > 256 {
+			return nil, fmt.Errorf("block %d: data size %d > 256", i/blockSize, size)
+		}
+		blocks = append(blocks, Block{
+			Addr: addr,
+			Data: make([]byte, size),
+		})
+		copy(blocks[len(blocks)-1].Data, b[32:32+size])
+	}
+
+	sort.Slice(blocks, func(i, j int) bool {
+		return blocks[i].Addr < blocks[j].Addr
+	})
+
+	return blocks, nil
+}