stm32: Refactor Bluetooth HCI RX to be independent of transport layer.

Now all HCI specific code (eg UART vs WB55 internal messaging) is confined
to modbluetooth_hci.c.

extmod/modbluetooth_hci.h

@@ -50,6 +50,7 @@ extern pyb_uart_obj_t mp_bluetooth_hci_uart_obj;
 int mp_bluetooth_hci_uart_init(uint32_t port);
 int mp_bluetooth_hci_uart_activate(void);
 int mp_bluetooth_hci_uart_set_baudrate(uint32_t baudrate);
+int mp_bluetooth_hci_uart_readchar(void);
 int mp_bluetooth_hci_uart_write(const uint8_t *buf, size_t len);
 
 #endif // MICROPY_INCLUDED_EXTMOD_MODBLUETOOTH_HCI_H

extmod/nimble/nimble/npl_os.c

@@ -235,7 +235,11 @@ ble_npl_error_t ble_npl_sem_pend(struct ble_npl_sem *sem, ble_npl_time_t timeout
     if (sem->count == 0) {
         uint32_t t0 = mp_hal_ticks_ms();
         while (sem->count == 0 && mp_hal_ticks_ms() - t0 < timeout) {
+            // This function may be called at thread-level, so execute
+            // mp_bluetooth_nimble_hci_uart_process at raised priority.
+            MICROPY_PY_BLUETOOTH_ENTER
             mp_bluetooth_nimble_hci_uart_process();
+            MICROPY_PY_BLUETOOTH_EXIT
             if (sem->count != 0) {
                 break;
             }

ports/stm32/btstack.c

@@ -165,8 +165,9 @@ STATIC void btstack_uart_process(void) {
 
     // 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);
+    int chr;
+    while (recv_idx < recv_len && (chr = mp_bluetooth_hci_uart_readchar()) >= 0) {
+        recv_buf[recv_idx++] = chr;
         if (recv_idx == recv_len) {
             recv_idx = 0;
             recv_len = 0;

ports/stm32/modbluetooth_hci.c

@@ -54,8 +54,13 @@ void mp_bluetooth_hci_poll_wrapper(uint32_t ticks_ms) {
 /******************************************************************************/
 // HCI over IPCC
 
+#include <string.h>
 #include "rfcore.h"
 
+STATIC uint16_t hci_uart_rx_buf_cur;
+STATIC uint16_t hci_uart_rx_buf_len;
+STATIC uint8_t hci_uart_rx_buf_data[256];
+
 int mp_bluetooth_hci_controller_deactivate(void) {
     return 0;
 }
@@ -79,6 +84,8 @@ int mp_bluetooth_hci_uart_init(uint32_t port) {
 
 int mp_bluetooth_hci_uart_activate(void) {
     rfcore_ble_init();
+    hci_uart_rx_buf_cur = 0;
+    hci_uart_rx_buf_len = 0;
     return 0;
 }
 
@@ -94,6 +101,31 @@ int mp_bluetooth_hci_uart_write(const uint8_t *buf, size_t len) {
     return 0;
 }
 
+// Callback to copy data into local hci_uart_rx_buf_data buffer for subsequent use.
+STATIC int mp_bluetooth_hci_uart_msg_cb(void *env, const uint8_t *buf, size_t len) {
+    (void)env;
+    if (hci_uart_rx_buf_len + len > MP_ARRAY_SIZE(hci_uart_rx_buf_data)) {
+        len = MP_ARRAY_SIZE(hci_uart_rx_buf_data) - hci_uart_rx_buf_len;
+    }
+    memcpy(hci_uart_rx_buf_data + hci_uart_rx_buf_len, buf, len);
+    hci_uart_rx_buf_len += len;
+    return 0;
+}
+
+int mp_bluetooth_hci_uart_readchar(void) {
+    if (hci_uart_rx_buf_cur >= hci_uart_rx_buf_len) {
+        hci_uart_rx_buf_cur = 0;
+        hci_uart_rx_buf_len = 0;
+        rfcore_ble_check_msg(mp_bluetooth_hci_uart_msg_cb, NULL);
+    }
+
+    if (hci_uart_rx_buf_cur < hci_uart_rx_buf_len) {
+        return hci_uart_rx_buf_data[hci_uart_rx_buf_cur++];
+    } else {
+        return -1;
+    }
+}
+
 #else
 
 /******************************************************************************/
@@ -153,6 +185,16 @@ int mp_bluetooth_hci_uart_write(const uint8_t *buf, size_t len) {
     return 0;
 }
 
+// This function expects the controller to be in the wake state via a previous call
+// to mp_bluetooth_hci_controller_woken.
+int mp_bluetooth_hci_uart_readchar(void) {
+    if (uart_rx_any(&mp_bluetooth_hci_uart_obj)) {
+        return uart_rx_char(&mp_bluetooth_hci_uart_obj);
+    } else {
+        return -1;
+    }
+}
+
 #endif // defined(STM32WB)
 
 #endif // MICROPY_PY_BLUETOOTH

ports/stm32/nimble.c

@@ -67,28 +67,13 @@ void mp_bluetooth_nimble_port_start(void) {
     ble_hs_start();
 }
 
-#if defined(STM32WB)
-
-#include "rfcore.h"
-
-void mp_bluetooth_nimble_hci_uart_rx(hal_uart_rx_cb_t rx_cb, void *rx_arg) {
-    // Protect in case it's called from ble_npl_sem_pend at thread-level
-    MICROPY_PY_LWIP_ENTER
-    rfcore_ble_check_msg(rx_cb, rx_arg);
-    MICROPY_PY_LWIP_EXIT
-}
-
-#else
-
-#include "uart.h"
-
 void mp_bluetooth_nimble_hci_uart_rx(hal_uart_rx_cb_t rx_cb, void *rx_arg) {
     bool host_wake = mp_bluetooth_hci_controller_woken();
 
-    while (uart_rx_any(&mp_bluetooth_hci_uart_obj)) {
-        uint8_t data = uart_rx_char(&mp_bluetooth_hci_uart_obj);
+    int chr;
+    while ((chr = mp_bluetooth_hci_uart_readchar()) >= 0) {
         //printf("UART RX: %02x\n", data);
-        rx_cb(rx_arg, data);
+        rx_cb(rx_arg, chr);
     }
 
     if (host_wake) {
@@ -96,8 +81,6 @@ void mp_bluetooth_nimble_hci_uart_rx(hal_uart_rx_cb_t rx_cb, void *rx_arg) {
     }
 }
 
-#endif // defined(STM32WB)
-
 void mp_bluetooth_nimble_hci_uart_tx_strn(const char *str, uint len) {
     mp_bluetooth_hci_uart_write((const uint8_t *)str, len);
 }

ports/stm32/rfcore.c

@@ -56,7 +56,7 @@ typedef struct _tl_list_node_t {
 } tl_list_node_t;
 
 typedef struct _parse_hci_info_t {
-    int (*cb_fun)(void *, uint8_t);
+    int (*cb_fun)(void *, const uint8_t *, size_t);
     void *cb_env;
     bool was_hci_reset_evt;
 } parse_hci_info_t;
@@ -190,9 +190,7 @@ STATIC void tl_parse_hci_msg(const uint8_t *buf, parse_hci_info_t *parse) {
             // Standard BT HCI ACL packet
             kind = "HCI_ACL";
             if (parse != NULL) {
-                for (size_t i = 0; i < len; ++i) {
-                    parse->cb_fun(parse->cb_env, buf[i]);
-                }
+                parse->cb_fun(parse->cb_env, buf, len);
             }
             break;
         }
@@ -205,12 +203,11 @@ STATIC void tl_parse_hci_msg(const uint8_t *buf, parse_hci_info_t *parse) {
                     len -= 1;
                     fix = true;
                 }
-                for (size_t i = 0; i < len; ++i) {
-                    parse->cb_fun(parse->cb_env, buf[i]);
-                }
+                parse->cb_fun(parse->cb_env, buf, len);
                 if (fix) {
                     len += 1;
-                    parse->cb_fun(parse->cb_env, 0x00); // success
+                    uint8_t data = 0x00; // success
+                    parse->cb_fun(parse->cb_env, &data, 1);
                 }
                 // Check for successful HCI_Reset event
                 parse->was_hci_reset_evt = buf[1] == 0x0e && buf[2] == 0x04 && buf[3] == 0x01
@@ -403,7 +400,7 @@ void rfcore_ble_hci_cmd(size_t len, const uint8_t *src) {
     IPCC->C1SCR = ch << 16;
 }
 
-void rfcore_ble_check_msg(int (*cb)(void *, uint8_t), void *env) {
+void rfcore_ble_check_msg(int (*cb)(void *, const uint8_t *, size_t), void *env) {
     parse_hci_info_t parse = { cb, env, false };
     tl_check_msg(&ipcc_mem_ble_evt_queue, IPCC_CH_BLE, &parse);
 

ports/stm32/rfcore.h

@@ -32,6 +32,6 @@ void rfcore_init(void);
 
 void rfcore_ble_init(void);
 void rfcore_ble_hci_cmd(size_t len, const uint8_t *src);
-void rfcore_ble_check_msg(int (*cb)(void *, uint8_t), void *env);
+void rfcore_ble_check_msg(int (*cb)(void *, const uint8_t *, size_t), void *env);
 
 #endif // MICROPY_INCLUDED_STM32_RFCORE_H