stm32: Add bindings for BTstack implementation.

Work done in collaboration with Jim Mussared aka @jimmo.

ports/stm32/Makefile

@@ -462,11 +462,22 @@ ifeq ($(MICROPY_PY_BLUETOOTH),1)
 
 SRC_C += modbluetooth_hci.c
 
+ifeq ($(MICROPY_BLUETOOTH_NIMBLE),1)
+ifeq ($(MICROPY_BLUETOOTH_BTSTACK),1)
+$(error Cannot enable both NimBLE and BTstack at the same time)
+endif
+endif
+
 ifeq ($(MICROPY_BLUETOOTH_NIMBLE),1)
 include $(TOP)/extmod/nimble/nimble.mk
 SRC_C += nimble.c
 endif
 
+ifeq ($(MICROPY_BLUETOOTH_BTSTACK),1)
+include $(TOP)/extmod/btstack/btstack.mk
+SRC_C += btstack.c
+endif
+
 ifeq ($(MICROPY_PY_NETWORK_CYW43),1)
 DRIVERS_SRC_C += drivers/cyw43/cywbt.c
 endif

ports/stm32/btstack.c

@@ -0,0 +1,222 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/runtime.h"
+#include "py/mperrno.h"
+#include "py/mphal.h"
+
+#if MICROPY_PY_BLUETOOTH && MICROPY_BLUETOOTH_BTSTACK
+
+#include "lib/btstack/src/btstack.h"
+#include "lib/btstack/platform/embedded/btstack_run_loop_embedded.h"
+#include "lib/btstack/platform/embedded/hal_cpu.h"
+#include "lib/btstack/platform/embedded/hal_time_ms.h"
+
+#include "extmod/modbluetooth_hci.h"
+#include "extmod/btstack/modbluetooth_btstack.h"
+
+// We pass the bytes directly to the UART during a send, but then notify btstack in the next poll.
+STATIC bool send_done;
+STATIC void (*send_handler)(void);
+
+// btstack issues a read of len bytes, and gives us a buffer to asynchronously fill up.
+STATIC uint8_t *recv_buf;
+STATIC size_t recv_len;
+STATIC size_t recv_idx;
+STATIC void (*recv_handler)(void);
+
+// The IRQ functionality in btstack_run_loop_embedded.c is not used, so the
+// following three functions are empty.
+
+void hal_cpu_disable_irqs(void) {
+}
+
+void hal_cpu_enable_irqs(void) {
+}
+
+void hal_cpu_enable_irqs_and_sleep(void) {
+}
+
+uint32_t hal_time_ms(void) {
+    return mp_hal_ticks_ms();
+}
+
+STATIC int btstack_uart_init(const btstack_uart_config_t *uart_config) {
+    send_done = false;
+    recv_len = 0;
+    recv_idx = 0;
+    recv_handler = NULL;
+    send_handler = NULL;
+
+    // Set up the UART periperhal.
+    mp_bluetooth_hci_uart_init(MICROPY_HW_BLE_UART_ID);
+
+    return 0;
+}
+
+STATIC int btstack_uart_open(void) {
+    // Attach IRQ and power up the HCI controller.
+    mp_bluetooth_hci_uart_activate();
+    return 0;
+}
+
+STATIC int btstack_uart_close(void) {
+    return 0;
+}
+
+STATIC void btstack_uart_set_block_received(void (*block_handler)(void)) {
+    recv_handler = block_handler;
+}
+
+STATIC void btstack_uart_set_block_sent(void (*block_handler)(void)) {
+    send_handler = block_handler;
+}
+
+STATIC int btstack_uart_set_baudrate(uint32_t baudrate) {
+    mp_bluetooth_hci_uart_set_baudrate(baudrate);
+    return 0;
+}
+
+STATIC int btstack_uart_set_parity(int parity) {
+    return 0;
+}
+
+STATIC int btstack_uart_set_flowcontrol(int flowcontrol) {
+    return 0;
+}
+
+STATIC void btstack_uart_receive_block(uint8_t *buf, uint16_t len) {
+    recv_buf = buf;
+    recv_len = len;
+}
+
+STATIC void btstack_uart_send_block(const uint8_t *buf, uint16_t len) {
+    mp_bluetooth_hci_uart_write(buf, len);
+    send_done = true;
+}
+
+STATIC int btstack_uart_get_supported_sleep_modes(void) {
+    return 0;
+}
+
+STATIC void btstack_uart_set_sleep(btstack_uart_sleep_mode_t sleep_mode) {
+    // printf("btstack_uart_set_sleep %u\n", sleep_mode);
+}
+
+STATIC void btstack_uart_set_wakeup_handler(void (*wakeup_handler)(void)) {
+    // printf("btstack_uart_set_wakeup_handler\n");
+}
+
+STATIC const btstack_uart_block_t btstack_uart_block = {
+    &btstack_uart_init,
+    &btstack_uart_open,
+    &btstack_uart_close,
+    &btstack_uart_set_block_received,
+    &btstack_uart_set_block_sent,
+    &btstack_uart_set_baudrate,
+    &btstack_uart_set_parity,
+    &btstack_uart_set_flowcontrol,
+    &btstack_uart_receive_block,
+    &btstack_uart_send_block,
+    &btstack_uart_get_supported_sleep_modes,
+    &btstack_uart_set_sleep,
+    &btstack_uart_set_wakeup_handler,
+};
+
+STATIC const hci_transport_config_uart_t hci_transport_config_uart = {
+    HCI_TRANSPORT_CONFIG_UART,
+    MICROPY_HW_BLE_UART_BAUDRATE,
+    3000000,
+    0,
+    NULL,
+};
+
+STATIC void btstack_uart_process(void) {
+    if (send_done) {
+        // If we'd done a TX in the last interval, notify btstack that it's complete.
+        send_done = false;
+        if (send_handler) {
+            send_handler();
+        }
+    }
+
+    // Append any new bytes to the recv buffer, notifying bstack if we've got
+    // the number of bytes it was looking for.
+    while (uart_rx_any(&mp_bluetooth_hci_uart_obj) && recv_idx < recv_len) {
+        recv_buf[recv_idx++] = uart_rx_char(&mp_bluetooth_hci_uart_obj);
+        if (recv_idx == recv_len) {
+            recv_idx = 0;
+            recv_len = 0;
+            if (recv_handler) {
+                recv_handler();
+            }
+        }
+    }
+}
+
+void mp_bluetooth_hci_poll(void) {
+    if (mp_bluetooth_btstack_state == MP_BLUETOOTH_BTSTACK_STATE_OFF) {
+        return;
+    }
+
+    // Process uart data.
+    bool host_wake = mp_bluetooth_hci_controller_woken();
+    btstack_uart_process();
+    if (host_wake) {
+        mp_bluetooth_hci_controller_sleep_maybe();
+    }
+
+    // Call the BTstack run loop.
+    btstack_run_loop_embedded_execute_once();
+}
+
+void mp_bluetooth_btstack_port_init(void) {
+    static bool run_loop_init = false;
+    if (!run_loop_init) {
+        run_loop_init = true;
+        btstack_run_loop_init(btstack_run_loop_embedded_get_instance());
+    } else {
+        btstack_run_loop_embedded_get_instance()->init();
+    }
+
+    // hci_dump_open(NULL, HCI_DUMP_STDOUT);
+    const hci_transport_t *transport = hci_transport_h4_instance(&btstack_uart_block);
+    hci_init(transport, &hci_transport_config_uart);
+
+    // TODO: Probably not necessary for BCM (we have our own firmware loader),
+    // but might be worth investigating for other controllers in the future.
+    // hci_set_chipset(btstack_chipset_bcm_instance());
+}
+
+void mp_bluetooth_btstack_port_deinit(void) {
+    hci_power_control(HCI_POWER_OFF);
+}
+
+void mp_bluetooth_btstack_port_start(void) {
+    hci_power_control(HCI_POWER_ON);
+}
+
+#endif // MICROPY_PY_BLUETOOTH && MICROPY_BLUETOOTH_BTSTACK