extmod/modbluetooth_nimble: Move nimble specific code, factor nimble.mk.

Move extmod/modbluetooth_nimble.* to extmod/nimble.  And move common
Makefile lines to extmod/nimble/nimble.mk (which was previously only used
by stm32).  This allows (upcoming) btstack to follow a similar structure.

Work done in collaboration with Jim Mussared aka @jimmo.

extmod/nimble/modbluetooth_nimble.c

@@ -31,8 +31,8 @@
 
 #if MICROPY_PY_BLUETOOTH && MICROPY_BLUETOOTH_NIMBLE
 
-#include "modbluetooth_nimble.h"
-#include "modbluetooth.h"
+#include "extmod/nimble/modbluetooth_nimble.h"
+#include "extmod/modbluetooth.h"
 
 #include "host/ble_hs.h"
 #include "host/util/util.h"

extmod/nimble/modbluetooth_nimble.h

@@ -24,8 +24,8 @@
  * THE SOFTWARE.
  */
 
-#ifndef MICROPY_INCLUDED_EXTMOD_MODBLUETOOTH_NIMBLE_H
-#define MICROPY_INCLUDED_EXTMOD_MODBLUETOOTH_NIMBLE_H
+#ifndef MICROPY_INCLUDED_EXTMOD_NIMBLE_MODBLUETOOTH_NIMBLE_H
+#define MICROPY_INCLUDED_EXTMOD_NIMBLE_MODBLUETOOTH_NIMBLE_H
 
 #define MP_BLUETOOTH_NIMBLE_MAX_SERVICES (8)
 
@@ -51,4 +51,4 @@ void mp_bluetooth_nimble_port_postinit(void);
 void mp_bluetooth_nimble_port_deinit(void);
 void mp_bluetooth_nimble_port_start(void);
 
-#endif // MICROPY_INCLUDED_EXTMOD_MODBLUETOOTH_NIMBLE_H
+#endif // MICROPY_INCLUDED_EXTMOD_NIMBLE_MODBLUETOOTH_NIMBLE_H

extmod/nimble/nimble.mk

@@ -1,10 +1,21 @@
-# Makefile directives for Apache mynewt nimble BLE component
+# Makefile directives for Apache Mynewt NimBLE component
 
 ifeq ($(MICROPY_BLUETOOTH_NIMBLE),1)
 
-NIMBLE_LIB_DIR = lib/mynewt-nimble
+EXTMOD_SRC_C += extmod/nimble/modbluetooth_nimble.c
+
+CFLAGS_MOD += -DMICROPY_BLUETOOTH_NIMBLE=1
+
 NIMBLE_EXTMOD_DIR = extmod/nimble
 
+# Use NimBLE from the submodule in lib/mynewt-nimble by default,
+# allowing a port to use their own system version (e.g. ESP32).
+MICROPY_BLUETOOTH_NIMBLE_BINDINGS_ONLY ?= 0
+
+ifeq ($(MICROPY_BLUETOOTH_NIMBLE_BINDINGS_ONLY),0)
+
+NIMBLE_LIB_DIR = lib/mynewt-nimble
+
 SRC_LIB += $(addprefix $(NIMBLE_LIB_DIR)/, \
 	$(addprefix ext/tinycrypt/src/, \
 		aes_encrypt.c \
@@ -76,8 +87,6 @@ EXTMOD_SRC_C += $(addprefix $(NIMBLE_EXTMOD_DIR)/, \
 	nimble/hci_uart.c \
 	)
 
-CFLAGS_MOD += -DMICROPY_BLUETOOTH_NIMBLE=1
-
 INC += -I$(TOP)/$(NIMBLE_EXTMOD_DIR)
 INC += -I$(TOP)/$(NIMBLE_LIB_DIR)
 INC += -I$(TOP)/$(NIMBLE_LIB_DIR)/ext/tinycrypt/include
@@ -93,3 +102,5 @@ INC += -I$(TOP)/$(NIMBLE_LIB_DIR)/porting/nimble/include
 $(BUILD)/$(NIMBLE_LIB_DIR)/%.o: CFLAGS += -Wno-maybe-uninitialized -Wno-pointer-arith -Wno-unused-but-set-variable -Wno-format
 
 endif
+
+endif

ports/esp32/Makefile

@@ -118,7 +118,12 @@ endif
 MICROPY_PY_BLUETOOTH ?= 1
 ifeq ($(MICROPY_PY_BLUETOOTH),1)
 SDKCONFIG += boards/sdkconfig.ble
-MICROPY_BLUETOOTH_NIMBLE = 1
+
+# Use NimBLE on ESP32.
+MICROPY_BLUETOOTH_NIMBLE ?= 1
+# Use Nimble bindings, but ESP32 IDF provides the Nimble library.
+MICROPY_BLUETOOTH_NIMBLE_BINDINGS_ONLY = 1
+include $(TOP)/extmod/nimble/nimble.mk
 endif
 
 # include sdkconfig to get needed configuration values
@@ -244,10 +249,6 @@ INC_NEWLIB += -I$(ESPCOMP)/newlib/include
 ifeq ($(MICROPY_PY_BLUETOOTH),1)
 CFLAGS_MOD += -DMICROPY_PY_BLUETOOTH=1
 CFLAGS_MOD += -DMICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE=1
-
-ifeq ($(MICROPY_BLUETOOTH_NIMBLE),1)
-CFLAGS_MOD += -DMICROPY_BLUETOOTH_NIMBLE=1
-endif
 endif
 
 # these flags are common to C and C++ compilation
@@ -354,9 +355,8 @@ SRC_C = \
 	$(wildcard $(BOARD_DIR)/*.c) \
 	$(SRC_MOD)
 
-EXTMOD_SRC_C = $(addprefix extmod/,\
+EXTMOD_SRC_C += $(addprefix extmod/,\
 	modonewire.c \
-	modbluetooth_nimble.c \
 	)
 
 LIB_SRC_C = $(addprefix lib/,\

ports/stm32/Makefile

@@ -458,14 +458,18 @@ CFLAGS_MOD += -DMBEDTLS_CONFIG_FILE='"mbedtls/mbedtls_config.h"'
 SRC_MOD += mbedtls/mbedtls_port.c
 endif
 
+ifeq ($(MICROPY_PY_BLUETOOTH),1)
+
 ifeq ($(MICROPY_BLUETOOTH_NIMBLE),1)
 include $(TOP)/extmod/nimble/nimble.mk
 SRC_C += nimble.c
 SRC_C += nimble_hci_uart.c
-EXTMOD_SRC_C += extmod/modbluetooth_nimble.c
+endif
+
 ifeq ($(MICROPY_PY_NETWORK_CYW43),1)
 DRIVERS_SRC_C += drivers/cyw43/cywbt.c
 endif
+
 endif
 
 OBJ =

ports/stm32/nimble.c

@@ -36,7 +36,7 @@
 #include "transport/uart/ble_hci_uart.h"
 #include "host/ble_hs.h"
 
-#include "extmod/modbluetooth_nimble.h"
+#include "extmod/nimble/modbluetooth_nimble.h"
 
 extern void nimble_uart_process(void);
 extern void os_eventq_run_all(void);