waf: auto-enable CAN for ChibiOS builds

use presence of CAN pins in hwdef.dat to automatically enable if
available

Tools/ardupilotwaf/boards.py

@@ -64,7 +64,6 @@ class Board:
             cfg.srcnode.find_dir('libraries/AP_Common/missing').abspath()
         ])
 
-
     def configure_env(self, cfg, env):
         # Use a dictionary instead of the convetional list for definitions to
         # make easy to override them. Convert back to list before consumption.
@@ -267,14 +266,6 @@ class chibios(Board):
             HAVE_STD_NULLPTR_T = 0,
         )
 
-        if self.with_uavcan:
-            env.AP_LIBRARIES += [
-                'modules/uavcan/libuavcan_drivers/stm32/driver/src/*.cpp'
-                ]
-            env.INCLUDES += [
-                cfg.srcnode.find_dir('modules/uavcan/libuavcan_drivers/stm32/driver/include').abspath()
-            ]
-
         env.AP_LIBRARIES += [
             'AP_HAL_ChibiOS',
         ]
@@ -363,11 +354,6 @@ class chibios(Board):
         ]
 
         env.LIB += ['gcc', 'm']
-        if self.with_uavcan:
-            env.CFLAGS += ['-DUAVCAN_STM32_CHIBIOS=1',
-                           '-DUAVCAN_STM32_NUM_IFACES=2']
-            env.CXXFLAGS += ['-DUAVCAN_STM32_CHIBIOS=1',
-                             '-DUAVCAN_STM32_NUM_IFACES=2']
 
         env.GIT_SUBMODULES += [
             'ChibiOS',
@@ -393,7 +379,6 @@ class fmuv3(chibios):
     name = 'fmuv3'
     def __init__(self):
         super(fmuv3, self).__init__()
-        self.with_uavcan = True
 
     def configure_env(self, cfg, env):
         super(fmuv3, self).configure_env(cfg, env)
@@ -410,7 +395,6 @@ class skyviper_v2450(fmuv3):
     name = 'skyviper-v2450'
     def __init__(self):
         super(skyviper_v2450, self).__init__()
-        self.with_uavcan = False
         
     def configure_env(self, cfg, env):
         super(skyviper_v2450, self).configure_env(cfg, env)

Tools/ardupilotwaf/chibios.py

@@ -106,6 +106,37 @@ def chibios_firmware(self):
                                 src=self.objcopy_target)
         _upload_task.set_run_after(generate_fw_task)
 
+def setup_can_build(cfg):
+    '''enable CAN build. By doing this here we can auto-enable CAN in
+    the build based on the presence of CAN pins in hwdef.dat'''
+    env = cfg.env
+    env.AP_LIBRARIES += [
+        'AP_UAVCAN',
+        'modules/uavcan/libuavcan/src/**/*.cpp',
+        'modules/uavcan/libuavcan_drivers/stm32/driver/src/*.cpp'
+        ]
+
+    env.CFLAGS += ['-DUAVCAN_STM32_CHIBIOS=1',
+                   '-DUAVCAN_STM32_NUM_IFACES=2']
+
+    env.CXXFLAGS += [
+        '-Wno-error=cast-align',
+        '-DUAVCAN_STM32_CHIBIOS=1',
+        '-DUAVCAN_STM32_NUM_IFACES=2'
+        ]
+
+    env.DEFINES += [
+        'UAVCAN_CPP_VERSION=UAVCAN_CPP03',
+        'UAVCAN_NO_ASSERTIONS=1',
+        'UAVCAN_NULLPTR=nullptr'
+        ]
+
+    env.INCLUDES += [
+        cfg.srcnode.find_dir('modules/uavcan/libuavcan/include').abspath(),
+        cfg.srcnode.find_dir('modules/uavcan/libuavcan_drivers/stm32/driver/include').abspath()
+        ]
+    cfg.get_board().with_uavcan = True
+
 def load_env_vars(env):
     '''optionally load extra environment variables from env.py in the build directory'''
     print("Checking for env.py")
@@ -191,9 +222,14 @@ def configure(cfg):
         print("Failed to generate hwdef.h")
 
     load_env_vars(cfg.env)
+    if env.HAL_WITH_UAVCAN:
+        setup_can_build(cfg)
 
 def build(bld):
     load_env_vars(bld.env)
+
+    if bld.env.HAL_WITH_UAVCAN:
+        bld.get_board().with_uavcan = True
     
     bld(
         # build hwdef.h and apj.prototype from hwdef.dat. This is needed after a waf clean