rp2040: add version check for RP2040-E5

src/machine/machine_rp2040.go

@@ -4,6 +4,7 @@ package machine
 
 import (
 	"device/rp"
+	"unsafe"
 )
 
 const deviceName = rp.Device
@@ -96,3 +97,20 @@ func CurrentCore() int {
 
 // NumCores returns number of cores available on the device.
 func NumCores() int { return 2 }
+
+// ChipVersion returns the version of the chip. 1 is returned for B0 and B1
+// chip.
+func ChipVersion() uint8 {
+	const (
+		SYSINFO_BASE                  = 0x40000000
+		SYSINFO_CHIP_ID_OFFSET        = 0x00000000
+		SYSINFO_CHIP_ID_REVISION_BITS = 0xf0000000
+		SYSINFO_CHIP_ID_REVISION_LSB  = 28
+	)
+
+	// First register of sysinfo is chip id
+	chipID := *(*uint32)(unsafe.Pointer(uintptr(SYSINFO_BASE + SYSINFO_CHIP_ID_OFFSET)))
+	// Version 1 == B0/B1
+	version := (chipID & SYSINFO_CHIP_ID_REVISION_BITS) >> SYSINFO_CHIP_ID_REVISION_LSB
+	return uint8(version)
+}