machine/rp2350: add flash support for rp2350 (#4803)

* machine/rp2350: add flash support for rp2350
* combine duplicate files
* clean things up and group by source file
* add stubbed out xip cache clean func if needed in the future
* update flash_enable_xip_via_boot2
* remove unused macros and fix inconsistent formatting
* make flash size configurable like rp2040
* add missing flash size configs
* retain big Go CGo compatibility per #4103
* clarify CS0_SIZE source and remove single-use typedef

src/machine/machine_rp2_flash.go

@@ -0,0 +1,111 @@
+//go:build rp2040 || rp2350
+
+package machine
+
+import (
+	"unsafe"
+)
+
+// EnterBootloader should perform a system reset in preparation
+// to switch to the bootloader to flash new firmware.
+func EnterBootloader() {
+	enterBootloader()
+}
+
+// 13 = 1 + FLASH_RUID_DUMMY_BYTES(4) + FLASH_RUID_DATA_BYTES(8)
+var deviceIDBuf [13]byte
+
+// DeviceID returns an identifier that is unique within
+// a particular chipset.
+//
+// The identity is one burnt into the MCU itself, or the
+// flash chip at time of manufacture.
+//
+// It's possible that two different vendors may allocate
+// the same DeviceID, so callers should take this into
+// account if needing to generate a globally unique id.
+//
+// The length of the hardware ID is vendor-specific, but
+// 8 bytes (64 bits) is common.
+func DeviceID() []byte {
+	deviceIDBuf[0] = 0x4b // FLASH_RUID_CMD
+
+	err := doFlashCommand(deviceIDBuf[:], deviceIDBuf[:])
+	if err != nil {
+		panic(err)
+	}
+
+	return deviceIDBuf[5:13]
+}
+
+// compile-time check for ensuring we fulfill BlockDevice interface
+var _ BlockDevice = flashBlockDevice{}
+
+var Flash flashBlockDevice
+
+type flashBlockDevice struct {
+}
+
+// ReadAt reads the given number of bytes from the block device.
+func (f flashBlockDevice) ReadAt(p []byte, off int64) (n int, err error) {
+	if readAddress(off) > FlashDataEnd() {
+		return 0, errFlashCannotReadPastEOF
+	}
+
+	data := unsafe.Slice((*byte)(unsafe.Pointer(readAddress(off))), len(p))
+	copy(p, data)
+
+	return len(p), nil
+}
+
+// WriteAt writes the given number of bytes to the block device.
+// Only word (32 bits) length data can be programmed.
+// If the length of p is not long enough it will be padded with 0xFF bytes.
+// This method assumes that the destination is already erased.
+func (f flashBlockDevice) WriteAt(p []byte, off int64) (n int, err error) {
+	return f.writeAt(p, off)
+}
+
+// Size returns the number of bytes in this block device.
+func (f flashBlockDevice) Size() int64 {
+	return int64(FlashDataEnd() - FlashDataStart())
+}
+
+const writeBlockSize = 1 << 8
+
+// WriteBlockSize returns the block size in which data can be written to
+// memory. It can be used by a client to optimize writes, non-aligned writes
+// should always work correctly.
+func (f flashBlockDevice) WriteBlockSize() int64 {
+	return writeBlockSize
+}
+
+const eraseBlockSizeValue = 1 << 12
+
+func eraseBlockSize() int64 {
+	return eraseBlockSizeValue
+}
+
+// EraseBlockSize returns the smallest erasable area on this particular chip
+// in bytes. This is used for the block size in EraseBlocks.
+func (f flashBlockDevice) EraseBlockSize() int64 {
+	return eraseBlockSize()
+}
+
+// EraseBlocks erases the given number of blocks. An implementation may
+// transparently coalesce ranges of blocks into larger bundles if the chip
+// supports this. The start and len parameters are in block numbers, use
+// EraseBlockSize to map addresses to blocks.
+func (f flashBlockDevice) EraseBlocks(start, length int64) error {
+	return f.eraseBlocks(start, length)
+}
+
+// return the correct address to be used for write
+func writeAddress(off int64) uintptr {
+	return readAddress(off) - uintptr(memoryStart)
+}
+
+// return the correct address to be used for reads
+func readAddress(off int64) uintptr {
+	return FlashDataStart() + uintptr(off)
+}