drivers: can: add support for configuring CAN emulation in QEMU

Add support for configuring CAN emulation support in QEMU. For now, the
only supported CAN controller is the single-channel Kvaser PCIcan PCI card.

Signed-off-by: Henrik Brix Andersen <henrik@brixandersen.dk>

cmake/emu/qemu.cmake

@@ -269,6 +269,22 @@ elseif(QEMU_NET_STACK)
   endif()
 endif(QEMU_PIPE_STACK)
 
+if(CONFIG_CAN)
+  # Add CAN bus 0
+  list(APPEND QEMU_FLAGS -object can-bus,id=canbus0)
+
+  if(NOT "${CONFIG_CAN_QEMU_IFACE_NAME}" STREQUAL "")
+    # Connect CAN bus 0 to host SocketCAN interface
+    list(APPEND QEMU_FLAGS
+      -object can-host-socketcan,id=canhost0,if=${CONFIG_CAN_QEMU_IFACE_NAME},canbus=canbus0)
+  endif()
+
+  if(CONFIG_CAN_KVASER_PCI)
+    # Emulate a single-channel Kvaser PCIcan card connected to CAN bus 0
+    list(APPEND QEMU_FLAGS -device kvaser_pci,canbus=canbus0)
+  endif()
+endif()
+
 if(CONFIG_X86_64 AND NOT CONFIG_QEMU_UEFI_BOOT)
   # QEMU doesn't like 64-bit ELF files. Since we don't use any >4GB
   # addresses, converting it to 32-bit is safe enough for emulation.

drivers/can/Kconfig

@@ -89,6 +89,15 @@ config CAN_AUTO_BUS_OFF_RECOVERY
 	  recessive bits). When this option is enabled, the recovery API is not
 	  available.
 
+config CAN_QEMU_IFACE_NAME
+	string "SocketCAN interface name for QEMU"
+	default ""
+	depends on QEMU_TARGET
+	help
+	  The SocketCAN interface name for QEMU. This value, if set, is given as "if" parameter to
+	  the "-object can-host-socketcan" qemu command line option. The CAN interface must be
+	  configured before starting QEMU.
+
 source "drivers/can/Kconfig.sam"
 source "drivers/can/Kconfig.stm32"
 source "drivers/can/Kconfig.stm32fd"