zephyr-cp: enable BLE on the Raspberry Pi Pico 2 W

The CYW43439's Bluetooth controller shares the WiFi gSPI bus rather than
sitting on a UART, so it needs the new shared-bus HCI driver (see the
companion zephyr branch). With a bt_hci device in the devicetree, the
port's existing Kconfig turns CONFIG_BT on by itself and common-hal
_bleio needs no board-specific work.

Wire it up for the Pico 2 W:

- board overlay: add the infineon,cyw43-bt-hci node as a child of the
  stock infineon,airoc-wifi node, and point zephyr,bt-hci at it. The
  hyphenated chosen name matters — the port's Kconfig derives CONFIG_BT
  via dt_chosen_enabled(zephyr,bt-hci).
- board conf: deeper system workqueue stack and HW stack protection, as
  the WHD WiFi, cybt and coexistence call chains are deeper than the
  port defaults.
- compat2driver: map infineon_cyw43_bt_hci to bluetooth/hci, which is
  what makes zephyr2cp.py set _bleio. Added by hand rather than
  regenerating the file, which would churn 500+ unrelated lines against
  the current Zephyr revision.

Builds at 67.1% flash and 43.4% RAM, up from 59.7%/38.0% without BLE.
Not hardware-tested.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: tyeth

ports/zephyr-cp/boards/raspberrypi/rpi_pico2_w_zephyr/autogen_board_info.toml

@@ -3,7 +3,7 @@ name = "Raspberry Pi Foundation Raspberry Pi Pico 2"
 
 [modules]
 __future__ = true
-_bleio = false
+_bleio = true # Zephyr board has _bleio
 _eve = false
 _pew = false
 _pixelmap = false

ports/zephyr-cp/boards/rpi_pico2_rp2350a_m33_w.conf

@@ -18,3 +18,12 @@ CONFIG_MBEDTLS_SSL_PROTO_TLS1_2=y
 CONFIG_MBEDTLS_CIPHERSUITE_TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256=y
 CONFIG_MBEDTLS_ENTROPY_C=y
 CONFIG_MBEDTLS_CTR_DRBG_C=y
+
+# Bluetooth over the shared gSPI bus (CONFIG_BT itself comes from the
+# zephyr,bt-hci chosen node in the overlay).
+#
+# The WHD WiFi, cybt BT and coexistence call chains are deeper than the
+# defaults in ../prj.conf; the Cortex-M33 MPU catches an overflow cleanly
+# instead of silently corrupting neighbouring stacks.
+CONFIG_HW_STACK_PROTECTION=y
+CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=4096

ports/zephyr-cp/boards/rpi_pico2_rp2350a_m33_w.overlay

@@ -30,4 +30,25 @@
 	};
 };
 
+/*
+ * Bluetooth. The CYW43439's HCI is not on a UART here — it shares the WiFi
+ * gSPI bus — so hang the shared-bus HCI transport off the board's stock
+ * infineon,airoc-wifi node and point the host at it. CONFIG_BT then turns
+ * itself on via the zephyr,bt-hci chosen (see ../../Kconfig).
+ */
+&pio0_spi0 {
+	airoc-wifi@0 {
+		cyw43_bt_hci: cyw43_bt_hci {
+			compatible = "infineon,cyw43-bt-hci";
+			status = "okay";
+		};
+	};
+};
+
+/ {
+	chosen {
+		zephyr,bt-hci = &cyw43_bt_hci;
+	};
+};
+
 #include "../app.overlay"

ports/zephyr-cp/cptools/compat2driver.py

@@ -166,6 +166,7 @@
     "infineon_bless_hci": "bluetooth/hci",
     "infineon_bt_hci_uart": "bluetooth/hci",
     "infineon_cyw208xx_hci": "bluetooth/hci",
+    "infineon_cyw43_bt_hci": "bluetooth/hci",
     "nxp_bt_hci_uart": "bluetooth/hci",
     "nxp_hci_ble": "bluetooth/hci",
     "renesas_bt_hci_da1453x": "bluetooth/hci",