Add RP2350 support (#4459)

machine/rp2350: add support

* add linker scripts for rp2350
* add bootloader
* begin melding rp2040 and rp2350 APIs
* add UART
* add rp2350 boot patching
* Fix RP2350 memory layout (#4626)
* Remove rp2040-style second stage bootloader.
* Add 'minimum viable' IMAGE_DEF embedded block
* Create a pico2 specific target
* Implement rp2350 init, clock, and uart support
* Merge rp2 reset code back together
* Separate chip-specific clock definitions
* Clear pad isolation bit on rp2350
* Init UART in rp2350 runtime
* Correct usb/serial initialization order
* Implement jump-to-bootloader
* test: add pico2 to smoketests

---------

Signed-off-by: deadprogram <ron@hybridgroup.com>
Co-authored-by: Matthew Mets <matt.mets@cibomahto.com>
Co-authored-by: Matt Mets <matt@blinkinlabs.com>
Co-authored-by: deadprogram <ron@hybridgroup.com>

src/machine/machine_rp2_sync.go

@@ -0,0 +1,39 @@
+//go:build rp2040 || rp2350
+
+package machine
+
+// machine_rp2040_sync.go contains interrupt and
+// lock primitives similar to those found in Pico SDK's
+// irq.c
+
+// Clears interrupt flag on a pin
+func (p Pin) acknowledgeInterrupt(change PinChange) {
+	ioBank0.intR[p>>3].Set(p.ioIntBit(change))
+}
+
+// Basic interrupt setting via ioBANK0 for GPIO interrupts.
+func (p Pin) setInterrupt(change PinChange, enabled bool) {
+	// Separate mask/force/status per-core, so check which core called, and
+	// set the relevant IRQ controls.
+	switch CurrentCore() {
+	case 0:
+		p.ctrlSetInterrupt(change, enabled, &ioBank0.proc0IRQctrl)
+	case 1:
+		p.ctrlSetInterrupt(change, enabled, &ioBank0.proc1IRQctrl)
+	}
+}
+
+// ctrlSetInterrupt acknowledges any pending interrupt and enables or disables
+// the interrupt for a given IRQ control bank (IOBANK, DormantIRQ, QSPI).
+//
+// pico-sdk calls this the _gpio_set_irq_enabled, not to be confused with
+// gpio_set_irq_enabled (no leading underscore).
+func (p Pin) ctrlSetInterrupt(change PinChange, enabled bool, base *irqCtrl) {
+	p.acknowledgeInterrupt(change)
+	enReg := &base.intE[p>>3]
+	if enabled {
+		enReg.SetBits(p.ioIntBit(change))
+	} else {
+		enReg.ClearBits(p.ioIntBit(change))
+	}
+}