Add a board definition for the RP Debug Probe (#2940)

* Add a board definition for the RP Debug Probe

This minimal configuration will (hopefully) allow the Raspberry Pi Debug
Probe firmware to be configured and built using the SDK's board
identification and configuration framework.

* Add defines for each Debug Probe LED.

These board-specific defines will make it easier for clients (e.g. the
debug probe firmware) to properly configure all of the board's LEDs.

Author: carlwhamilton

src/boards/include/boards/debug_probe.h

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+// -----------------------------------------------------
+// NOTE: THIS HEADER IS ALSO INCLUDED BY ASSEMBLER SO
+//       SHOULD ONLY CONSIST OF PREPROCESSOR DIRECTIVES
+// -----------------------------------------------------
+
+// This header may be included by other board headers as "boards/debug_probe.h"
+
+#ifndef _BOARDS_DEBUG_PROBE_H
+#define _BOARDS_DEBUG_PROBE_H
+
+pico_board_cmake_set(PICO_PLATFORM, rp2040)
+
+// For board detection
+#define RASPBERRYPI_DEBUG_PROBE
+
+// --- BOARD SPECIFIC ---
+#define DEBUG_PROBE_USB_CONNECTED_LED_PIN 2
+#define DEBUG_PROBE_DAP_CONNECTED_LED_PIN 15
+#define DEBUG_PROBE_DAP_RUNNING_LED_PIN 16
+#define DEBUG_PROBE_UART_RX_LED_PIN 7
+#define DEBUG_PROBE_UART_TX_LED_PIN 8
+
+// --- UART ---
+#ifndef PICO_DEFAULT_UART
+#define PICO_DEFAULT_UART 1
+#endif
+#ifndef PICO_DEFAULT_UART_TX_PIN
+#define PICO_DEFAULT_UART_TX_PIN 4
+#endif
+#ifndef PICO_DEFAULT_UART_RX_PIN
+#define PICO_DEFAULT_UART_RX_PIN 5
+#endif
+
+// --- LED ---
+#ifndef PICO_DEFAULT_LED_PIN
+#define PICO_DEFAULT_LED_PIN DEBUG_PROBE_USB_CONNECTED_LED_PIN
+#endif
+
+// --- FLASH ---
+#define PICO_BOOT_STAGE2_CHOOSE_W25Q080 1
+
+#ifndef PICO_FLASH_SPI_CLKDIV
+#define PICO_FLASH_SPI_CLKDIV 2
+#endif
+
+pico_board_cmake_set_default(PICO_FLASH_SIZE_BYTES, (2 * 1024 * 1024))
+#ifndef PICO_FLASH_SIZE_BYTES
+#define PICO_FLASH_SIZE_BYTES (2 * 1024 * 1024)
+#endif
+
+#ifndef PICO_RP2040_B0_SUPPORTED
+#define PICO_RP2040_B0_SUPPORTED 1
+#endif
+
+#endif