can: add CAN FD configuration

Add CAN FD specifities to CAN system library in RIOT:
* 64 bytes payload
* Bit rate switching
* Error State Indicator

Signed-off-by: Gilles DOFFE <gilles.doffe@rtone.fr>

drivers/include/can/candev.h

@@ -80,6 +80,9 @@ struct candev {
     void *isr_arg;                         /**< argument to pass on isr event */
     struct can_bittiming bittiming;        /**< device bittimings */
     enum can_state state;                  /**< device state */
+#ifdef MODULE_FDCAN
+    struct can_bittiming fd_data_bittiming;/**< device bittimings for FD CAN only */
+#endif
 };
 
 /**

sys/include/can/can.h

@@ -40,9 +40,13 @@ extern "C" {
 #else
 
 /**
- * @brief Max data length for a CAN frame
+ * @brief Max data length for classic and FD CAN frames (compliant with
+ * libsocketcan macros)
+ * @{
  */
-#define CAN_MAX_DLEN (8)
+#define CAN_MAX_DLEN (8)    /**< Classic CAN maximum data length */
+#define CANFD_MAX_DLEN (64) /**< CAN FD maximum data length */
+/** @} */
 
 /**
  * @name CAN_ID flags and masks
@@ -59,6 +63,15 @@ extern "C" {
 #define CAN_ERR_MASK (0x1FFFFFFFU) /**< omit EFF, RTR, ERR flags */
 /** @} */
 
+/**
+ * @name CAN FD flags extracted from libsocketcan
+ * @{
+ */
+#define CANFD_BRS 0x01 /**< bit rate switch (second bitrate for payload data) */
+#define CANFD_ESI 0x02 /**< error state indicator of the transmitting node */
+#define CANFD_FDF 0x04 /**< mark CAN FD for dual use of struct canfd_frame */
+/** @} */
+
 /**
  * @brief CAN operational and error states
  */
@@ -87,7 +100,10 @@ typedef uint32_t canid_t;
  */
 struct can_frame {
     canid_t can_id;     /**< 32 bit CAN_ID + EFF/RTR/ERR flags */
-    uint8_t can_dlc; /**< frame payload length in byte (0 .. CAN_MAX_DLEN) */
+    union {
+        uint8_t len;    /**< frame payload length in byte (0 .. CAN_MAX_DLEN) */
+        uint8_t can_dlc;/**< deprecated - see SocketCAN documentation */
+    };
     uint8_t __pad;      /**< padding */
     uint8_t __res0;     /**< reserved / padding */
     uint8_t __res1;     /**< reserved / padding */
@@ -95,6 +111,18 @@ struct can_frame {
     uint8_t data[CAN_MAX_DLEN] __attribute__((aligned(8)));
 };
 
+#ifdef MODULE_FDCAN
+struct canfd_frame {
+    canid_t can_id;  /**< 32 bit CAN_ID + EFF/RTR/ERR flags */
+    uint8_t len; /**< frame payload length in byte (0 .. CAN_MAX_DLEN) */
+    uint8_t flags;   /**< additional flags for CAN FD */
+    uint8_t __res0;  /**< reserved / padding */
+    uint8_t __res1;  /**< reserved / padding */
+    /** Frame data */
+    uint8_t data[CANFD_MAX_DLEN] __attribute__((aligned(8)));
+};
+#endif
+
 /**
  * @brief Controller Area Network filter
  */
@@ -142,7 +170,15 @@ struct can_bittiming_const {
 
 #endif /* defined(__linux__) */
 
+/**
+ * @brief CAN frame
+ */
+#ifdef MODULE_FDCAN
+typedef struct canfd_frame can_frame_t;
+#else
 typedef struct can_frame can_frame_t;
+#endif
+
 #ifdef __cplusplus
 }
 #endif

sys/include/can/common.h

@@ -39,6 +39,15 @@ extern "C" {
 #include "mbox.h"
 #endif
 
+/**
+ * @brief Default CAN maximum data length
+ */
+#ifdef MODULE_FDCAN
+#define DEFAULT_CAN_MAX_DLEN CANFD_MAX_DLEN
+#else
+#define DEFAULT_CAN_MAX_DLEN CAN_MAX_DLEN
+#endif
+
 /**
  * @brief CAN options
  */
@@ -51,6 +60,10 @@ typedef enum {
     CANOPT_CLOCK,           /**< controller main clock */
     CANOPT_BITTIMING_CONST, /**< controller bittiming parameters */
     CANOPT_STATE,           /**< set controller state @ref canopt_state_t */
+#ifdef MODULE_FDCAN
+    CANOPT_FD_BITTIMING,    /**< bit timing parameter for FDCAN data payload */
+    CANOPT_FD_BITTIMING_CONST, /**< controller bit timing parameter for FDCAN data payload */
+#endif
 } canopt_t;
 
 /**