can: Add Linux compatible frame and filter structs

Add new "struct can_frame" which is compatible with Linux so that it
is easier to port socket-can applications from Linux.
Rename existing can_filter to can_msg_filter so that the name will
not conflict with Linux compatible can_filter struct.

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>

Author: jukkar

drivers/can/stm32_can.c

@@ -578,36 +578,36 @@ static inline void can_stm32_set_mode_scale(enum can_filter_type filter_type,
 	*scale_reg |= scale_reg_bit;
 }
 
-static inline u32_t can_generate_std_mask(const struct can_filter *filter)
+static inline u32_t can_generate_std_mask(const struct can_msg_filter *filter)
 {
 	return  (filter->std_id_mask << CAN_FIRX_STD_ID_POS) |
 		(filter->rtr_mask    << CAN_FIRX_STD_RTR_POS) |
 		(1U                  << CAN_FIRX_STD_IDE_POS);
 }
 
-static inline u32_t can_generate_ext_mask(const struct can_filter *filter)
+static inline u32_t can_generate_ext_mask(const struct can_msg_filter *filter)
 {
 	return  (filter->ext_id_mask << CAN_FIRX_EXT_EXT_ID_POS) |
 		(filter->rtr_mask    << CAN_FIRX_EXT_RTR_POS) |
 		(1U                  << CAN_FIRX_EXT_IDE_POS);
 }
 
-static inline u32_t can_generate_std_id(const struct can_filter *filter)
+static inline u32_t can_generate_std_id(const struct can_msg_filter *filter)
 {
 
 	return  (filter->std_id << CAN_FIRX_STD_ID_POS) |
 		(filter->rtr    << CAN_FIRX_STD_RTR_POS);
 
 }
 
-static inline u32_t can_generate_ext_id(const struct can_filter *filter)
+static inline u32_t can_generate_ext_id(const struct can_msg_filter *filter)
 {
 	return  (filter->ext_id << CAN_FIRX_EXT_EXT_ID_POS) |
 		(filter->rtr    << CAN_FIRX_EXT_RTR_POS) |
 		(1U             << CAN_FIRX_EXT_IDE_POS);
 }
 
-static inline int can_stm32_set_filter(const struct can_filter *filter,
+static inline int can_stm32_set_filter(const struct can_msg_filter *filter,
 				       struct can_stm32_data *device_data,
 				       CAN_TypeDef *can,
 				       int *filter_index)
@@ -739,7 +739,7 @@ static inline int can_stm32_set_filter(const struct can_filter *filter,
 
 
 static inline int can_stm32_attach(struct device *dev, void *response_ptr,
-				   const struct can_filter *filter,
+				   const struct can_msg_filter *filter,
 				   int *filter_index)
 {
 	const struct can_stm32_config *cfg = DEV_CFG(dev);
@@ -758,7 +758,7 @@ static inline int can_stm32_attach(struct device *dev, void *response_ptr,
 }
 
 int can_stm32_attach_msgq(struct device *dev, struct k_msgq *msgq,
-			  const struct can_filter *filter)
+			  const struct can_msg_filter *filter)
 {
 	int filter_nr;
 	int filter_index;
@@ -772,7 +772,7 @@ int can_stm32_attach_msgq(struct device *dev, struct k_msgq *msgq,
 }
 
 int can_stm32_attach_isr(struct device *dev, can_rx_callback_t isr,
-			 const struct can_filter *filter)
+			 const struct can_msg_filter *filter)
 {
 	struct can_stm32_data *data = DEV_DATA(dev);
 	int filter_nr;

include/can.h

@@ -33,6 +33,7 @@ extern "C" {
 #define CAN_STD_ID_MASK CAN_MAX_STD_ID
 #define CAN_EXT_ID_MASK (0x1FFFFFFF)
 #define CAN_MAX_DLC    (8)
+#define CAN_MAX_DLEN    8
 
 /* CAN_TX_* are the error flags from tx_callback and send.*/
 /** send successfully */
@@ -96,8 +97,49 @@ enum can_mode {
 	CAN_SILENT_LOOPBACK_MODE
 };
 
+/*
+ * Controller Area Network Identifier structure for Linux compatibility.
+ *
+ * The fields in this type are:
+ *
+ * bit 0-28	: CAN identifier (11/29 bit)
+ * bit 29	: error message frame flag (0 = data frame, 1 = error message)
+ * bit 30	: remote transmission request flag (1 = rtr frame)
+ * bit 31	: frame format flag (0 = standard 11 bit, 1 = extended 29 bit)
+ */
+typedef u32_t canid_t;
+
+/**
+ * @brief CAN frame structure that is compatible with Linux. This is mainly
+ * used by Socket CAN code.
+ *
+ * @details Used to pass CAN messages from userspace to the socket CAN and vice
+ * versa.
+ */
+struct can_frame {
+	/** 32 bit CAN_ID + EFF/RTR/ERR flags */
+	canid_t can_id;
+
+	/** The length of the message */
+	u8_t can_dlc;
+
+	/** The message data */
+	u8_t data[CAN_MAX_DLEN];
+};
+
 /**
- * @brief can message structure
+ * @brief CAN filter that is compatible with Linux. This is mainly used by
+ * Socket CAN code.
+ *
+ * @details A filter matches, when "received_can_id & mask == can_id & mask"
+ */
+struct can_filter {
+	canid_t can_id;
+	canid_t can_mask;
+};
+
+/**
+ * @brief CAN message structure
  *
  * Used to pass can messages from userspace to the driver and
  * from driver to userspace
@@ -127,15 +169,15 @@ struct can_msg {
 } __packed;
 
 /**
- * @brief can filter structure
+ * @brief CAN filter structure
  *
  * Used to pass can identifier filter information to the driver.
  * rtr_mask and *_id_mask are used to mask bits of the rtr and id fields.
  * If the mask bit is 0, the value of the corresponding bit in the id or rtr
  * field don't care for the filter matching.
  *
  */
-struct can_filter {
+struct can_msg_filter {
 	/** Indicates the identifier type (standard or extended)
 	 * use can_ide enum for assignment
 	 */
@@ -218,13 +260,14 @@ typedef int (*can_send_t)(struct device *dev, struct can_msg *msg,
  * *
  * @param dev    Pointer to the device structure for the driver instance.
  * @param msgq   Pointer to the already initialized message queue.
- * @param filter Pointer to a can_filter structure defining the id filtering.
+ * @param filter Pointer to a can_msg_filter structure defining the id
+ *               filtering.
  *
  * @retval filter id on success.
  * @retval CAN_NO_FREE_FILTER if there is no filter left.
  */
 typedef int (*can_attach_msgq_t)(struct device *dev, struct k_msgq *msg_q,
-				 const struct can_filter *filter);
+				 const struct can_msg_filter *filter);
 
 /**
  * @brief Attach an isr callback function to a single or group of identifiers.
@@ -238,13 +281,14 @@ typedef int (*can_attach_msgq_t)(struct device *dev, struct k_msgq *msg_q,
  * *
  * @param dev    Pointer to the device structure for the driver instance.
  * @param isr    Callback function pointer.
- * @param filter Pointer to a can_filter structure defining the id filtering.
+ * @param filter Pointer to a can_msg_filter structure defining the id
+ *               filtering.
  *
  * @retval filter id on success.
  * @retval CAN_NO_FREE_FILTER if there is no filter left.
  */
 typedef int (*can_attach_isr_t)(struct device *dev, can_rx_callback_t isr,
-				const struct can_filter *filter);
+				const struct can_msg_filter *filter);
 
 /**
  * @brief Detach an isr or message queue from the identifier filtering.
@@ -325,11 +369,11 @@ static inline int can_write(struct device *dev, u8_t *data, u8_t length,
 
 
 __syscall int can_attach_msgq(struct device *dev, struct k_msgq *msg_q,
-			      const struct can_filter *filter);
+			      const struct can_msg_filter *filter);
 
 static inline int _impl_can_attach_msgq(struct device *dev,
 					struct k_msgq *msg_q,
-					const struct can_filter *filter)
+					const struct can_msg_filter *filter)
 {
 	const struct can_driver_api *api = dev->driver_api;
 
@@ -338,10 +382,10 @@ static inline int _impl_can_attach_msgq(struct device *dev,
 
 
 __syscall int can_attach_isr(struct device *dev, can_rx_callback_t isr,
-			     const struct can_filter *filter);
+			     const struct can_msg_filter *filter);
 static inline int _impl_can_attach_isr(struct device *dev,
 				       can_rx_callback_t isr,
-				       const struct can_filter *filter)
+				       const struct can_msg_filter *filter)
 {
 	const struct can_driver_api *api = dev->driver_api;
 
@@ -370,6 +414,71 @@ static inline int _impl_can_configure(struct device *dev, enum can_mode mode,
 	return api->configure(dev, mode, bitrate);
 }
 
+/**
+ * @brief Converter that translates betwen can_frame and can_msg structs.
+ *
+ * @param frame Pointer to can_frame struct.
+ * @param msg Pointer to can_msg struct.
+ */
+static inline void can_copy_frame_to_msg(struct can_frame *frame,
+					 struct can_msg *msg)
+{
+	msg->id_type = (frame->can_id & BIT(31)) >> 31;
+	msg->rtr = (frame->can_id & BIT(30)) >> 30;
+	msg->ext_id = frame->can_id & BIT_MASK(29);
+	msg->dlc = frame->can_dlc;
+	memcpy(msg->data, frame->data, sizeof(msg->data));
+}
+
+/**
+ * @brief Converter that translates betwen can_msg and can_frame structs.
+ *
+ * @param msg Pointer to can_msg struct.
+ * @param frame Pointer to can_frame struct.
+ */
+static inline void can_copy_msg_to_frame(struct can_msg *msg,
+					 struct can_frame *frame)
+{
+	frame->can_id = (msg->id_type << 31) | (msg->rtr << 30) | msg->ext_id;
+	frame->can_dlc = msg->dlc;
+	memcpy(frame->data, msg->data, sizeof(frame->data));
+}
+
+/**
+ * @brief Converter that translates betwen can_filter and can_msg_filter
+ * structs.
+ *
+ * @param filter Pointer to can_filter struct.
+ * @param msg_filter Pointer to can_msg_filter struct.
+ */
+static inline
+void can_copy_filter_to_msg_filter(struct can_filter *filter,
+				   struct can_msg_filter *msg_filter)
+{
+	msg_filter->id_type = (filter->can_id & BIT(31)) >> 31;
+	msg_filter->rtr = (filter->can_id & BIT(30)) >> 30;
+	msg_filter->ext_id = filter->can_id & BIT_MASK(29);
+	msg_filter->rtr_mask = (filter->can_mask & BIT(30)) >> 30;
+	msg_filter->ext_id_mask = filter->can_mask & BIT_MASK(29);
+}
+
+/**
+ * @brief Converter that translates betwen can_msg_filter and can_filter
+ * structs.
+ *
+ * @param msg_filter Pointer to can_msg_filter struct.
+ * @param filter Pointer to can_filter struct.
+ */
+static inline
+void can_copy_msg_filter_to_filter(struct can_msg_filter *msg_filter,
+				   struct can_filter *filter)
+{
+	filter->can_id = (msg_filter->id_type << 31) |
+		(msg_filter->rtr << 30) | msg_filter->ext_id;
+	filter->can_mask = (msg_filter->rtr_mask << 30) |
+		(msg_filter->id_type << 31) | msg_filter->ext_id_mask;
+}
+
 #ifdef __cplusplus
 }
 #endif

samples/drivers/CAN/src/main.c

@@ -109,7 +109,7 @@ void tx_thread(void *can_dev_param, void *unused2, void *unused3)
 void rx_str_thread(void *msgq, void *can_dev_param, void *unused)
 {
 	struct can_msg msg;
-	const struct can_filter filter = {
+	const struct can_msg_filter filter = {
 		.id_type = CAN_EXTENDED_IDENTIFIER,
 		.rtr = CAN_DATAFRAME,
 		.ext_id = STR_MSG_ID,
@@ -129,7 +129,7 @@ void rx_str_thread(void *msgq, void *can_dev_param, void *unused)
 
 void led_thread(void *msgq, void *can_dev_param, void *gpio_dev_param)
 {
-	const struct can_filter filter = {
+	const struct can_msg_filter filter = {
 		.id_type = CAN_STANDARD_IDENTIFIER,
 		.rtr = CAN_DATAFRAME,
 		.std_id = LED_MSG_ID,
@@ -181,7 +181,7 @@ void rx_button_isr(struct can_msg *msg)
 
 void main(void)
 {
-	const struct can_filter filter = {
+	const struct can_msg_filter filter = {
 		.id_type = CAN_STANDARD_IDENTIFIER,
 		.rtr = CAN_DATAFRAME,
 		.std_id = BUTTON_MSG_ID,

samples/net/sockets/can/src/main.c

@@ -90,7 +90,7 @@ static void rx(int fd)
 
 static int setup_socket(void)
 {
-	const struct can_filter filter = {
+	const struct can_msg_filter filter = {
 		.id_type = CAN_STANDARD_IDENTIFIER,
 		.rtr = CAN_DATAFRAME,
 		.std_id = 0x1,