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/board_pico2.go

@@ -0,0 +1,88 @@
+//go:build pico2
+
+package machine
+
+// GPIO pins
+const (
+	GP0  Pin = GPIO0
+	GP1  Pin = GPIO1
+	GP2  Pin = GPIO2
+	GP3  Pin = GPIO3
+	GP4  Pin = GPIO4
+	GP5  Pin = GPIO5
+	GP6  Pin = GPIO6
+	GP7  Pin = GPIO7
+	GP8  Pin = GPIO8
+	GP9  Pin = GPIO9
+	GP10 Pin = GPIO10
+	GP11 Pin = GPIO11
+	GP12 Pin = GPIO12
+	GP13 Pin = GPIO13
+	GP14 Pin = GPIO14
+	GP15 Pin = GPIO15
+	GP16 Pin = GPIO16
+	GP17 Pin = GPIO17
+	GP18 Pin = GPIO18
+	GP19 Pin = GPIO19
+	GP20 Pin = GPIO20
+	GP21 Pin = GPIO21
+	GP22 Pin = GPIO22
+	GP26 Pin = GPIO26
+	GP27 Pin = GPIO27
+	GP28 Pin = GPIO28
+
+	// Onboard LED
+	LED Pin = GPIO25
+
+	// Onboard crystal oscillator frequency, in MHz.
+	xoscFreq = 12 // MHz
+)
+
+// I2C Default pins on Raspberry Pico.
+const (
+	I2C0_SDA_PIN = GP4
+	I2C0_SCL_PIN = GP5
+
+	I2C1_SDA_PIN = GP2
+	I2C1_SCL_PIN = GP3
+)
+
+// SPI default pins
+const (
+	// Default Serial Clock Bus 0 for SPI communications
+	SPI0_SCK_PIN = GPIO18
+	// Default Serial Out Bus 0 for SPI communications
+	SPI0_SDO_PIN = GPIO19 // Tx
+	// Default Serial In Bus 0 for SPI communications
+	SPI0_SDI_PIN = GPIO16 // Rx
+
+	// Default Serial Clock Bus 1 for SPI communications
+	SPI1_SCK_PIN = GPIO10
+	// Default Serial Out Bus 1 for SPI communications
+	SPI1_SDO_PIN = GPIO11 // Tx
+	// Default Serial In Bus 1 for SPI communications
+	SPI1_SDI_PIN = GPIO12 // Rx
+)
+
+// UART pins
+const (
+	UART0_TX_PIN = GPIO0
+	UART0_RX_PIN = GPIO1
+	UART1_TX_PIN = GPIO8
+	UART1_RX_PIN = GPIO9
+	UART_TX_PIN  = UART0_TX_PIN
+	UART_RX_PIN  = UART0_RX_PIN
+)
+
+var DefaultUART = UART0
+
+// USB identifiers
+const (
+	usb_STRING_PRODUCT      = "Pico2"
+	usb_STRING_MANUFACTURER = "Raspberry Pi"
+)
+
+var (
+	usb_VID uint16 = 0x2E8A
+	usb_PID uint16 = 0x000A
+)